From 43146f6746e010ba1289dac4d71d2022876bf4bc Mon Sep 17 00:00:00 2001 From: Andrew Gallant Date: Sun, 31 Jan 2016 10:48:17 -0500 Subject: [PATCH] Add a lazy DFA. A lazy DFA is much faster than executing an NFA because it doesn't repeat the work of following epsilon transitions over and and over. Instead, it computes states during search and caches them for reuse. We avoid exponential state blow up by bounding the cache in size. When the DFA isn't powerful enough to fulfill the caller's request (e.g., return sub-capture locations), it still runs to find the boundaries of the match and then falls back to NFA execution on the matched region. The lazy DFA can otherwise execute on every regular expression *except* for regular expressions that contain word boundary assertions (`\b` or `\B`). (They are tricky to implement in the lazy DFA because they are Unicode aware and therefore require multi-byte look-behind/ahead.) The implementation in this PR is based on the implementation in Google's RE2 library. Adding a lazy DFA was a substantial change and required several modifications: 1. The compiler can now produce both Unicode based programs (still used by the NFA engines) and byte based programs (required by the lazy DFA, but possible to use in the NFA engines too). In byte based programs, UTF-8 decoding is built into the automaton. 2. A new `Exec` type was introduced to implement the logic for compiling and choosing the right engine to use on each search. 3. Prefix literal detection was rewritten to work on bytes. 4. Benchmarks were overhauled and new ones were added to more carefully track the impact of various optimizations. 5. A new `HACKING.md` guide has been added that gives a high-level design overview of this crate. Other changes in this commit include: 1. Protection against stack overflows. All places that once required recursion have now either acquired a bound or have been converted to using a stack on the heap. 2. Update the Aho-Corasick dependency, which includes `memchr2` and `memchr3` optimizations. 3. Add PCRE benchmarks using the Rust `pcre` bindings. Closes #66, #146. --- .travis.yml | 11 +- Cargo.toml | 92 +- HACKING.md | 307 + README.md | 42 +- benches/bench.rs | 169 + .../benches => benches}/bench_dynamic.rs | 12 +- benches/bench_dynamic_compile.rs | 61 + benches/bench_dynamic_nfa.rs | 32 + benches/bench_dynamic_parse.rs | 36 + .../benches => benches}/bench_native.rs | 3 + benches/bench_pcre.rs | 308 + benches/bench_sherlock.rs | 138 + benches/log/01-lazy-dfa/dynamic | 73 + benches/log/01-lazy-dfa/dynamic-no-lazy-dfa | 85 + benches/log/01-lazy-dfa/native | 65 + benches/log/01-lazy-dfa/nfa | 74 + benches/log/01-lazy-dfa/pcre | 60 + benches/log/old/01-before | 28 + benches/log/old/02-new-syntax-crate | 28 + benches/log/old/03-new-syntax-crate | 28 + benches/log/old/04-fixed-benchmark | 28 + benches/log/old/05-thread-caching | 29 + benches/log/old/06-major-dynamic | 33 + benches/log/old/06-major-macro | 33 + benches/log/old/07-prefix-improvements | 33 + benches/log/old/08-case-fixes | 33 + benches/log/old/09-before-compiler-rewrite | 33 + benches/log/old/10-compiler-rewrite | 33 + benches/log/old/11-compiler-rewrite | 33 + benches/log/old/12-executor | 35 + benches/log/old/12-executor-bytes | 35 + benches/log/old/13-cache-byte-range-suffixes | 35 + benches/the-adventures-of-sherlock-holmes.txt | 13052 ++++++++++++++++ examples/large-dfa.rs | 42 + examples/shootout-regex-dna-cheat.rs | 22 +- examples/shootout-regex-dna-replace.rs | 19 + examples/shootout-regex-dna-single-cheat.rs | 73 + examples/shootout-regex-dna.rs | 19 +- regex-syntax/src/lib.rs | 166 +- regex-syntax/src/properties.rs | 5 +- regex_macros/Cargo.toml | 26 +- regex_macros/benches/bench.rs | 196 - regex_macros/benches/random.txt | 513 - regex_macros/src/lib.rs | 34 +- src/backtrack.rs | 152 +- src/char_utf8.rs | 36 + src/compile.rs | 758 +- src/dfa.rs | 1164 ++ src/exec.rs | 407 + src/input.rs | 131 +- src/inst.rs | 280 +- src/lib.rs | 80 +- src/literals.rs | 714 + src/nfa.rs | 342 +- src/prefix.rs | 243 - src/program.rs | 506 +- src/re.rs | 127 +- src/sparse.rs | 82 + {regex_macros/tests => tests}/matches.rs | 0 .../tests => tests}/native_static.rs | 0 {regex_macros/tests => tests}/test_dynamic.rs | 7 +- .../tests => tests}/test_dynamic_backtrack.rs | 5 +- tests/test_dynamic_backtrack_bytes.rs | 28 + .../tests => tests}/test_dynamic_nfa.rs | 4 +- tests/test_dynamic_nfa_bytes.rs | 27 + {regex_macros/tests => tests}/test_native.rs | 0 {regex_macros/tests => tests}/tests.rs | 95 +- 67 files changed, 19445 insertions(+), 1955 deletions(-) create mode 100644 HACKING.md create mode 100644 benches/bench.rs rename {regex_macros/benches => benches}/bench_dynamic.rs (79%) create mode 100644 benches/bench_dynamic_compile.rs create mode 100644 benches/bench_dynamic_nfa.rs create mode 100644 benches/bench_dynamic_parse.rs rename {regex_macros/benches => benches}/bench_native.rs (87%) create mode 100644 benches/bench_pcre.rs create mode 100644 benches/bench_sherlock.rs create mode 100644 benches/log/01-lazy-dfa/dynamic create mode 100644 benches/log/01-lazy-dfa/dynamic-no-lazy-dfa create mode 100644 benches/log/01-lazy-dfa/native create mode 100644 benches/log/01-lazy-dfa/nfa create mode 100644 benches/log/01-lazy-dfa/pcre create mode 100644 benches/log/old/01-before create mode 100644 benches/log/old/02-new-syntax-crate create mode 100644 benches/log/old/03-new-syntax-crate create mode 100644 benches/log/old/04-fixed-benchmark create mode 100644 benches/log/old/05-thread-caching create mode 100644 benches/log/old/06-major-dynamic create mode 100644 benches/log/old/06-major-macro create mode 100644 benches/log/old/07-prefix-improvements create mode 100644 benches/log/old/08-case-fixes create mode 100644 benches/log/old/09-before-compiler-rewrite create mode 100644 benches/log/old/10-compiler-rewrite create mode 100644 benches/log/old/11-compiler-rewrite create mode 100644 benches/log/old/12-executor create mode 100644 benches/log/old/12-executor-bytes create mode 100644 benches/log/old/13-cache-byte-range-suffixes create mode 100644 benches/the-adventures-of-sherlock-holmes.txt create mode 100644 examples/large-dfa.rs create mode 100644 examples/shootout-regex-dna-replace.rs create mode 100644 examples/shootout-regex-dna-single-cheat.rs delete mode 100644 regex_macros/benches/bench.rs delete mode 100644 regex_macros/benches/random.txt create mode 100644 src/char_utf8.rs create mode 100644 src/dfa.rs create mode 100644 src/exec.rs create mode 100644 src/literals.rs delete mode 100644 src/prefix.rs create mode 100644 src/sparse.rs rename {regex_macros/tests => tests}/matches.rs (100%) rename {regex_macros/tests => tests}/native_static.rs (100%) rename {regex_macros/tests => tests}/test_dynamic.rs (91%) rename {regex_macros/tests => tests}/test_dynamic_backtrack.rs (84%) create mode 100644 tests/test_dynamic_backtrack_bytes.rs rename {regex_macros/tests => tests}/test_dynamic_nfa.rs (85%) create mode 100644 tests/test_dynamic_nfa_bytes.rs rename {regex_macros/tests => tests}/test_native.rs (100%) rename {regex_macros/tests => tests}/tests.rs (79%) diff --git a/.travis.yml b/.travis.yml index fb1aac1e70..416c589ff4 100644 --- a/.travis.yml +++ b/.travis.yml @@ -14,17 +14,10 @@ script: - cargo doc --verbose --manifest-path=regex-syntax/Cargo.toml - if [ "$TRAVIS_RUST_VERSION" = "nightly" ]; then cargo test --verbose --features pattern; - cargo bench --verbose; + cargo bench --verbose --bench dynamic; travis_wait cargo test --verbose --manifest-path=regex_macros/Cargo.toml; - travis_wait cargo bench --verbose --manifest-path=regex_macros/Cargo.toml; + travis_wait cargo bench --manifest-path=regex_macros/Cargo.toml --verbose --bench native bench::; fi - # - | - # [ $TRAVIS_RUST_VERSION != nightly ] || ( - # cargo test --verbose --features pattern && - # cargo bench --verbose && - # travis_wait cargo test --verbose --manifest-path=regex_macros/Cargo.toml && - # travis_wait cargo bench --verbose --manifest-path=regex_macros/Cargo.toml - # ) after_success: | [ $TRAVIS_BRANCH = master ] && [ $TRAVIS_PULL_REQUEST = false ] && diff --git a/Cargo.toml b/Cargo.toml index 653b27b983..7a05316d0c 100644 --- a/Cargo.toml +++ b/Cargo.toml @@ -8,41 +8,97 @@ repository = "https://github.com/rust-lang/regex" documentation = "https://doc.rust-lang.org/regex" homepage = "https://github.com/rust-lang/regex" description = """ -An implementation of regular expressions for Rust. +An implementation of regular expressions for Rust. This implementation uses +finite automata and guarantees linear time matching on all inputs. """ +[dependencies] +# For very fast prefix literal matching. +aho-corasick = "0.5" +# For skipping along search text quickly when a leading byte is known. +memchr = "0.1" +# For parsing regular expressions. +regex-syntax = { path = "regex-syntax", version = "0.2" } +# For compiling UTF-8 decoding into automata. +utf8-ranges = "0.1" + +[dev-dependencies] +# Because the pcre crate needs it for studying the regex. +enum-set = "0.0.6" +# To prevent the benchmarking harness from running setup code more than once. +# Why? Because it takes too long. +lazy_static = "0.1" +# For running benchmarks. +pcre = "0.2" +# For generating random text to test/benchmark with. +rand = "0.3" + +[features] +# Enable to use the unstable pattern traits defined in std. +pattern = [] + +# Runs unit tests defined inside the regex package. +# Generally these tests specific pieces of the regex implementation. [[test]] path = "src/lib.rs" name = "regex" +# Run the test suite on the default behavior of Regex::new. +# This includes a mish mash of NFAs and DFAs, which are chosen automatically +# based on the regex. We test both of the NFA implementations by forcing their +# usage with the test definitions below. (We can't test the DFA implementations +# in the same way since they can't be used for every regex tested.) [[test]] -path = "regex_macros/tests/test_dynamic.rs" +path = "tests/test_dynamic.rs" name = "dynamic" +# Run the test suite on the NFA algorithm over Unicode codepoints. +[[test]] +path = "tests/test_dynamic_nfa.rs" +name = "dynamic-nfa" + +# Run the test suite on the NFA algorithm over bytes. [[test]] -path = "regex_macros/tests/test_dynamic_nfa.rs" -name = "dynamic_nfa" +path = "tests/test_dynamic_nfa_bytes.rs" +name = "dynamic-nfa-bytes" +# Run the test suite on the backtracking engine over Unicode codepoints. [[test]] -path = "regex_macros/tests/test_dynamic_backtrack.rs" -name = "dynamic_backtrack" +path = "tests/test_dynamic_backtrack.rs" +name = "dynamic-backtrack" +# Run the test suite on the backtracking engine over bytes. +[[test]] +path = "tests/test_dynamic_backtrack_bytes.rs" +name = "dynamic-backtrack-bytes" + +# Run the benchmarks on the default behavior of Regex::new. +# +# N.B. These benchmarks were originally taken from Russ Cox. [[bench]] -name = "all" -path = "regex_macros/benches/bench_dynamic.rs" +name = "dynamic" +path = "benches/bench_dynamic.rs" test = false bench = true -[dependencies] -aho-corasick = "0.4" -memchr = "0.1" -regex-syntax = { path = "regex-syntax", version = "0.2" } - -[dev-dependencies] -rand = "0.3" +# Run the benchmarks on the NFA algorithm. We avoid chasing other permutations. +# +# N.B. These can take a *loong* time to run. +[[bench]] +name = "dynamic-nfa" +path = "benches/bench_dynamic_nfa.rs" +test = false +bench = true -[features] -pattern = [] +# Run the benchmarks on PCRE. +[[bench]] +name = "pcre" +path = "benches/bench_pcre.rs" +test = false +bench = true [profile.bench] -lto = true +debug = true + +[profile.test] +debug = true diff --git a/HACKING.md b/HACKING.md new file mode 100644 index 0000000000..ed57266c91 --- /dev/null +++ b/HACKING.md @@ -0,0 +1,307 @@ +Your friendly guide to hacking and navigating the regex library. + +This guide assumes familiarity with Rust and Cargo, and at least a perusal of +the user facing documentation for this crate. + +If you're looking for background on the implementation in this library, then +you can do no better than Russ Cox's article series on implementing regular +expressions using finite automata: https://swtch.com/~rsc/regexp/ + + +## Architecture overview + +As you probably already know, this library executes regular expressions using +finite automata. In particular, a design goal is to make searching linear with +respect to both the regular expression and the text being searched. Meeting +that design goal on its own is not so hard and can be done with an +implementation of the NFA algorithm, as described in: +https://swtch.com/~rsc/regexp/regexp2.html --- This library contains such an +implementation in src/nfa.rs. (N.B. PCRE's documentation also claims to +implement the NFA algorithm by citing Jeffrey Friedl's book, "Mastering Regular +Expressions." The book unfortunately conflates terminology.) + +Making it fast is harder. One of the key problems with the NFA algorithm is +that it can be in more than one state at any point in time, and must shuffle +sub-capture positions between them. The NFA algorithm also spends a lot of +time following the same epsilon transitions over and over again. We can employ +one trick to speed up the NFA algorithm: extract one or more literal prefixes +from the regular expression and execute specialized code to quickly find +matches of those prefixes in the search text. The NFA algorithm can then be +avoided for most the search, and instead only executed when a prefix is found. +The code to find prefixes and search for prefixes is in src/literals.rs. When +more than one literal prefix is found, we fall back to an Aho-Corasick DFA +using the aho-corasick crate. For one literal, we use a variant of the +Boyer-Moore algorithm. Both Aho-Corasick and Boyer-Moore use `memchr` when +appropriate. + +Of course, detecting prefix literals can only take us so far. Not all regular +expressions have literal prefixes. To remedy this, we try another approach to +executing the NFA: backtracking, whose implementation can be found in +src/backtrack.rs. One reason why backtracking can be faster is that it avoids +excessive shuffling of capture groups. Of course, backtracking is susceptible +to exponential runtimes, so we keep track of every state we've visited to make +sure we never visit it again. This guarantees linear time execution, but we +pay for it with the memory required to track visited states. Because of the +memory requirement, we only use this engine on small search strings *and* small +regular expressions. + +Lastly, the real workhorse of this library is the "lazy" DFA in src/dfa.rs. +It is distinct from the NFA algorithm in that the DFA is explicitly represented +in memory and is only ever in one state at a time. It is said to be "lazy" +because the DFA is computed as text is searched, where each byte in the search +text results in at most one new DFA state. It is made fast by caching states. +DFAs are susceptible to exponential state blow up (where the worst case is +computing a new state for every input byte, regardless of what's in the state +cache). To avoid using a lot of memory, the lazy DFA uses a bounded cache. Once +the cache is full, it is wiped and state computation starts over again. + +All of the above matching engines expose precisely the matching semantics. This +is indeed tested. (See the section below about testing.) + +The following sub-sections describe the rest of the library and how each of the +matching engines are actually used. + +### Parsing + +Regular expressions are parsed using the regex-syntax crate, which is +maintained in this repository. The regex-syntax crate defines an abstract +syntax and provides very detailed error messages when a parse error is +encountered. Parsing is done in a separate crate so that others may benefit +from its existence, and because it is relatively divorced from the rest of the +regex library. + +### Compilation + +The compiler is in src/compile.rs. The input to the compiler is some abstract +syntax for a regular expression and the output is a sequence of opcodes that +matching engines use to execute a search. (One can think of matching engines at +mini virtual machines.) The sequence of opcodes is a particular encoding of a +non-deterministic finite automaton. In particular, the opcodes explicitly rely +on epsilon transitions. + +Consider a simple regular expression like `a|b`. Its compiled form looks like +this: + + 000 Save(0) + 001 Split(2, 3) + 002 'a' (goto: 4) + 003 'b' + 004 Save(1) + 005 Match + +The first column is the instruction pointer and the second column is the +instruction. Save instructions indicate that the current position in the input +should be stored in a captured location. Split instructions represent a binary +branch in the program (i.e., epsilon transitions). The instructions `'a'` and +`'b'` indicate that the literal bytes `'a'` or `'b'` should match. + +In older versions of this library, the compilation would looked like this: + + 000 Save(0) + 001 Split(2, 3) + 002 'a' + 003 Jump(5) + 004 'b' + 005 Save(1) + 006 Match + +In particular, empty instructions that merely served to move execution from one +point in the program to another were removed. Instead, every instruction has a +`goto` pointer embedded into it. This resulted in a small performance boost for +the NFA algorithm, because it was one fewer epsilon transition that it had to +follow. + +There exist more instructions and they are defined and documented in +src/inst.rs. + +Compilation has several knobs and a few unfortunately complicated invariants. +Namely, the output of compilation can be one of two types of programs: a +program that executes on Unicode scalar values or a program that executes on +raw bytes. In the former case, the matching engine is responsible for +performing UTF-8 decoding and executing instructions using Unicode codepoints. +In the latter case, the program handles UTF-8 decoding implicitly, so that the +matching engine can execute on raw bytes. All matching engines can execute +either Unicode or byte based programs except for the lazy DFA, which requires +byte based programs. In general, both representations were kept because (1) the +lazy DFA requires byte based programs so that states can be encoded in a memory +efficient manner and (2) the NFA algorithm benefits greatly from inlining +Unicode character classes into fewer instructions as it results in fewer +epsilon transitions. This means that every compiled program contains a proper +subset of all available instructions. + +N.B. UTF-8 decoding is built into the compiled program by making use of the +utf8-ranges crate. The compiler in this library factors out common suffixes to +reduce the size of huge character classes (e.g., `\pL`). + +A regrettable consequence of this split in instruction sets is we generally +need to compile two programs; one for NFA execution and one for the lazy DFA. + +In fact, it is worse than that: the lazy DFA is not capable of finding the +starting location of a match in a single scan, and must instead execute a +backwards search after finding the end location. To execute a backwards search, +we must have compiled the regular expression *in reverse*. + +This means that every compilation of a regular expression generally results in +three distinct programs. It would be possible to lazily compile the Unicode +program, since it is never needed if (1) the regular expression uses no word +boundary assertions and (2) the caller never asks for sub-capture locations. + +### Execution + +At the time of writing, there are four matching engines in this library: + +1. The NFA algorithm (supports captures). +2. Bounded backtracking (supports captures). +3. Literal substring or multi-substring search. +4. Lazy DFA (no support for word boundary assertions). + +Only the first two matching engines are capable of executing every regular +expression program. They also happen to be the slowest, which means we need +some logic that (1) knows various facts about the regular expression and (2) +knows what the caller wants. Using this information, we can determine which +engine (or engines) to use. + +The logic for choosing which engine to execute is in src/exec.rs and is +documented on the Exec type. Exec values collection regular expression +Programs (defined in src/program.rs), which contain all the necessary tidbits +for actually executing a regular expression on search text. + +For the most part, the execution logic is straight-forward and follows the +limitations of each engine described above pretty faithfully. The hairiest part +of src/exec.rs by far is the execution of the lazy DFA, since it requires a +forwards and backwards search, and then falls back to either the NFA algorithm +or backtracking if the caller requested capture locations. + +### Programs + +A regular expression program is essentially a sequence of opcodes produced by +the compiler plus various caches for the matching engines plus various facts +about the regular expression (such as whether it is anchored, it capture names, +etc.). + +The regular expression program contains mutable caches for use by the matching +engines. For example, the NFA algorithm stores its "execution threads" there, +the backtracking engine stores its visited map and the lazy DFA stores its +state cache. In sum, they are beneficial to performance because it allows reuse +of previously done work (especially for the lazy DFA). Mutation of these caches +should not be observable by callers, so it is done using interior mutability. +To make it possible to share regular expressions across threads, the cache is +guarded by a mutex but is not held during matching. + +### The regex! macro (or why `regex::internal` exists) + +The `regex!` macro is defined in the `regex_macros` crate as a compiled plugin, +which is maintained in this repository. The `regex!` macro compiles a regular +expression at compile time into specialized Rust code. + +The `regex!` macro was written when this library was first conceived and +unfortunately hasn't changed much since then. In particular, it encodes the +entire NFA algorithm into stack allocated space (no heap allocation is done). +When `regex!` was first written, this provided a substantial speed boost over +so-called "dynamic" regexes compiled at runtime, and in particular had much +lower overhead per match. This was because the only matching engine at the time +was the NFA algorithm. The addition of other matching engines has inverted the +relationship; the `regex!` macro is almost never faster than the dynamic +variant. (In fact, it is typically substantially slower.) + +In order to build the `regex!` macro this way, it must have access to some +internals of the regex library, which is in a distinct crate. (Compiler plugins +must be part of a distinct crate.) Namely, it must be able to compile a regular +expression and access its opcodes. The necessary internals are exported as part +of the top-level `internal` module in the regex library, but is hidden from +public documentation. In order to present a uniform API between programs build +by the `regex!` macro and their dynamic analoges, the `Regex` type is an enum +whose variants are hidden from public documentation. + +In the future, the `regex!` macro should probably work more like Ragel, but +it's not clear how hard this is. In particular, the `regex!` macro should be +able to support all the features of dynamic regexes, which may be hard to do +with a Ragel-style implementation approach. (Which somewhat suggests that the +`regex!` macro may also need to grow conditional execution logic like the +dynamic variants, which seems rather grotesque.) + + +## Testing + +A key aspect of any mature regex library is its test suite. A subset of the +tests in this library come from Glenn Fowler's AT&T test suite (its online +presence seems gone at the time of writing). The source of the test suite is +located in src/testdata. The scripts/regex-match-tests.py takes the test suite +in src/testdata and generates tests/matches.rs. + +There are also many other manually crafted tests and regression tests in +tests/tests.rs. + +The biggest source of complexity in the tests is related to answering this +question: how can we reuse the tests to check all of our matching engines? +One approach would have been to encode every test into some kind of format +(like the AT&T test suite) and code generate tests for each matching engine. +The approach we use in this library is to create a Cargo.toml entry point for +each matching engine we want to test. The entry points are: + +* `tests/test_native.rs` - tests the `regex!` macro +* `tests/test_dynamic.rs` - tests `Regex::new` +* `tests/test_dynamic_nfa.rs` - tests `Regex::new`, forced to use the NFA + algorithm on every regex. +* `tests/test_dynamic_nfa_bytes.rs` - tests `Regex::new`, forced to use the NFA + algorithm on every regex and use byte based programs. +* `tests/test_dynamic_backtrack.rs` - tests `Regex::new`, forced to use + backtracking on every regex. +* `tests/test_dynamic_backtrack_bytes.rs` - tests `Regex::new`, forced to use + backtracking on every regex and use byte based programs. + +The lazy DFA and pure literal engines are absent from this list because they +cannot be used on every regular expression. Instead, we rely on +`tests/test_dynamic.rs` to test the lazy DFA and literal engines when possible. + +Since the tests are repeated several times, and because `cargo test` runs all +entry points, it can take a while to compile everything. To reduce compile +times slightly, try using `cargo test --test dynamic`, which will only use +the `tests/test_dynamic.rs` entry point. + +N.B. To run tests for the `regex!` macro, use: + + cargo test --manifest-path regex_macros/Cargo.toml --test native + + +## Benchmarking + +The benchmarking in this crate is made up of many micro-benchmarks. Currently, +there are two primary sets of benchmarks: the benchmarks that were adopted at +this library's inception (in `benches/bench.rs`) and a newer set of benchmarks +meant to test various optimizations. Specifically, the latter set contain some +analysis and are in `benches/bench_sherlock.rs`. Also, the latter set are all +executed on the same lengthy input whereas the former benchmarks are executed +on strings of varying length. + +There is also a smattering of benchmarks for parsing and compilation. + +Benchmarking follows a similarly wonky setup as tests. There are multiple +entry points: + +* `bench_native.rs` - benchmarks the `regex!` macro +* `bench_dynamic.rs` - benchmarks `Regex::new` +* `bench_dynamic_nfa.rs` benchmarks `Regex::new`, forced to use the NFA + algorithm on every regex. (N.B. This can take a few minutes to run.) +* `bench_pcre.rs` - benchmarks PCRE + +The PCRE benchmarks exist as a comparison point to a mature regular expression +library. In general, this regex library compares favorably (there are even a +few benchmarks that PCRE simply runs too slowly on or outright can't execute at +all). I would love to add other regular expression library benchmarks +(especially RE2), but PCRE is the only one with reasonable bindings. + +If you're hacking on one of the matching engines and just want to see +benchmarks, then all you need to run is: + + $ cargo bench --bench dynamic + +If you want to compare your results with older benchmarks, then try: + + $ cargo bench --bench dynamic | tee old + $ ... make it faster + $ cargo bench --bench dynamic | tee new + $ cargo-benchcmp old new --improvements + +The `cargo-benchcmp` utility is available here: +https://github.com/BurntSushi/cargo-benchcmp diff --git a/README.md b/README.md index 0a123ae46b..30056bb63c 100644 --- a/README.md +++ b/README.md @@ -4,8 +4,9 @@ regex A Rust library for parsing, compiling, and executing regular expressions. This particular implementation of regular expressions guarantees execution in linear time with respect to the size of the regular expression and -search text. Much of the syntax and implementation is inspired by -[RE2](https://github.com/google/re2). +search text by using finite automata. In particular, it makes use of both +NFAs and DFAs when matching. Much of the syntax and implementation is inspired +by [RE2](https://github.com/google/re2). [![Build Status](https://travis-ci.org/rust-lang-nursery/regex.svg?branch=master)](https://travis-ci.org/rust-lang-nursery/regex) [![Build status](https://ci.appveyor.com/api/projects/status/22g48bo866qr4u77?svg=true)](https://ci.appveyor.com/project/alexcrichton/regex) @@ -95,6 +96,38 @@ year: 2010, month: 03, day: 14 year: 2014, month: 10, day: 14 ``` +### Usage: Avoid compiling the same regex in a loop + +It is an anti-pattern to compile the same regular expression in a loop since +compilation is typically expensive. (It takes anywhere from a few microseconds +to a few **milliseconds** depending on the size of the regex.) Not only is +compilation itself expensive, but this also prevents optimizations that reuse +allocations internally to the matching engines. + +In Rust, it can sometimes be a pain to pass regular expressions around if +they're used from inside a helper function. Instead, we recommend using the +[`lazy_static`](https://crates.io/crates/lazy_static) crate to ensure that +regular expressions are compiled exactly once. + +For example: + +```rust +#[macro_use] extern crate lazy_static; +extern crate regex; + +use regex::Regex; + +fn some_helper_function(text: &str) -> bool { + lazy_static! { + static ref RE: Regex = Regex::new("...").unwrap(); + } + RE.is_match(text) +} +``` + +Specifically, in this example, the regex will be compiled when it is used for +the first time. On subsequent uses, it will reuse the previous compilation. + ### Usage: `regex!` compiler plugin The `regex!` compiler plugin will compile your regexes at compile time. **This @@ -124,6 +157,11 @@ fn main() { Notice that we never `unwrap` the result of `regex!`. This is because your *program* won't compile if the regex doesn't compile. (Try `regex!("(")`.) +Due to recent optimizations in the `regex` crate, the normal "dynamic" regex +created via `Regex::new(...)` is faster in almost all cases than `regex!(...)`. +In theory, this should be temporary, but the path to fixing it isn't quite +clear yet. + ### Usage: a regular expression parser This repository contains a crate that provides a well tested regular expression diff --git a/benches/bench.rs b/benches/bench.rs new file mode 100644 index 0000000000..7261477518 --- /dev/null +++ b/benches/bench.rs @@ -0,0 +1,169 @@ +// Copyright 2014 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +#![allow(non_snake_case)] + +use std::iter::repeat; + +use rand::{Rng, thread_rng}; +use regex::{Regex, NoExpand}; +use test::Bencher; + +macro_rules! bench_match { + ($name:ident, $re:expr, $text:expr) => { + #[bench] + fn $name(b: &mut Bencher) { + lazy_static! { + static ref RE: Regex = $re; + static ref TEXT: String = $text; + }; + b.bytes = TEXT.len() as u64; + b.iter(|| { + if !RE.is_match(&TEXT) { + panic!("expected match, got not match"); + } + }); + } + } +} + +macro_rules! bench_nomatch { + ($name:ident, $re:expr, $text:expr) => { + #[bench] + fn $name(b: &mut Bencher) { + lazy_static! { + static ref RE: Regex = $re; + static ref TEXT: String = $text; + }; + b.bytes = TEXT.len() as u64; + b.iter(|| { + if RE.is_match(&TEXT) { + panic!("match not expected"); + } + }); + } + } +} + +bench_match!(no_exponential, { + let re = format!( + "{}{}", + repeat("a?").take(100).collect::(), + repeat("a").take(100).collect::()); + // We don't use the macro here since we're dynamically building the regex. + Regex::new(&re).unwrap() +}, repeat("a").take(100).collect()); + +bench_match!(literal, regex!("y"), { + format!("{}y", repeat("x").take(50).collect::()) +}); + +bench_match!(not_literal, regex!(".y"), { + format!("{}y", repeat("x").take(50).collect::()) +}); + +bench_match!(match_class, regex!("[abcdw]"), { + format!("{}w", repeat("xxxx").take(20).collect::()) +}); + +bench_match!(match_class_in_range, regex!("[ac]"), { + format!("{}c", repeat("bbbb").take(20).collect::()) +}); + +bench_match!(match_class_unicode, regex!(r"\pL"), { + format!("{}a", repeat("☃5☃5").take(20).collect::()) +}); + +bench_nomatch!(anchored_literal_short_non_match, regex!("^zbc(d|e)"), { + "abcdefghijklmnopqrstuvwxyz".to_owned() +}); + +bench_nomatch!(anchored_literal_long_non_match, regex!("^zbc(d|e)"), { + repeat("abcdefghijklmnopqrstuvwxyz").take(15).collect::() +}); + +bench_match!(anchored_literal_short_match, regex!("^.bc(d|e)"), { + "abcdefghijklmnopqrstuvwxyz".to_owned() +}); + +bench_match!(anchored_literal_long_match, regex!("^.bc(d|e)"), { + repeat("abcdefghijklmnopqrstuvwxyz").take(15).collect::() +}); + +bench_match!(one_pass_short, regex!("^.bc(d|e)*$"), { + "abcddddddeeeededd".to_owned() +}); + +bench_match!(one_pass_short_not, regex!(".bc(d|e)*$"), { + "abcddddddeeeededd".to_owned() +}); + +bench_match!(one_pass_long_prefix, regex!("^abcdefghijklmnopqrstuvwxyz.*$"), { + "abcdefghijklmnopqrstuvwxyz".to_owned() +}); + +bench_match!(one_pass_long_prefix_not, regex!("^.bcdefghijklmnopqrstuvwxyz.*$"), { + "abcdefghijklmnopqrstuvwxyz".to_owned() +}); + +fn gen_text(n: usize) -> String { + let mut rng = thread_rng(); + let mut bytes = rng.gen_ascii_chars().map(|n| n as u8).take(n) + .collect::>(); + for (i, b) in bytes.iter_mut().enumerate() { + if i % 20 == 0 { + *b = b'\n' + } + } + String::from_utf8(bytes).unwrap() +} + +fn easy0() -> Regex { + regex!("ABCDEFGHIJKLMNOPQRSTUVWXYZ$") +} + +bench_nomatch!(easy0_32, easy0(), gen_text(32)); +bench_nomatch!(easy0_1K, easy0(), gen_text(1<<10)); +bench_nomatch!(easy0_32K, easy0(), gen_text(32<<10)); +bench_nomatch!(easy0_1MB, easy0(), gen_text(1<<20)); + +fn easy1() -> Regex { + regex!("A[AB]B[BC]C[CD]D[DE]E[EF]F[FG]G[GH]H[HI]I[IJ]J$") +} + +bench_nomatch!(easy1_32, easy1(), gen_text(32)); +bench_nomatch!(easy1_1K, easy1(), gen_text(1<<10)); +bench_nomatch!(easy1_32K, easy1(), gen_text(32<<10)); +bench_nomatch!(easy1_1MB, easy1(), gen_text(1<<20)); + +fn medium() -> Regex { + regex!("[XYZ]ABCDEFGHIJKLMNOPQRSTUVWXYZ$") +} + +bench_nomatch!(medium_32, medium(), gen_text(32)); +bench_nomatch!(medium_1K, medium(), gen_text(1<<10)); +bench_nomatch!(medium_32K, medium(), gen_text(32<<10)); +bench_nomatch!(medium_1MB, medium(), gen_text(1<<20)); + +fn hard() -> Regex { + regex!("[ -~]*ABCDEFGHIJKLMNOPQRSTUVWXYZ$") +} + +bench_nomatch!(hard_32, hard(), gen_text(32)); +bench_nomatch!(hard_1K, hard(), gen_text(1<<10)); +bench_nomatch!(hard_32K, hard(), gen_text(32<<10)); +bench_nomatch!(hard_1MB, hard(), gen_text(1<<20)); + +#[bench] +fn replace_all(b: &mut Bencher) { + let re = regex!("[cjrw]"); + let text = "abcdefghijklmnopqrstuvwxyz"; + b.iter(|| re.replace_all(text, NoExpand(""))); +} diff --git a/regex_macros/benches/bench_dynamic.rs b/benches/bench_dynamic.rs similarity index 79% rename from regex_macros/benches/bench_dynamic.rs rename to benches/bench_dynamic.rs index 1f915dd9fe..70abf5dce7 100644 --- a/regex_macros/benches/bench_dynamic.rs +++ b/benches/bench_dynamic.rs @@ -10,20 +10,20 @@ #![feature(test)] +#[macro_use] extern crate lazy_static; extern crate rand; extern crate regex; +extern crate regex_syntax; extern crate test; // Due to macro scoping rules, this definition only applies for the modules // defined below. Effectively, it allows us to use the same tests for both // native and dynamic regexes. macro_rules! regex( - ($re:expr) => ( - match ::regex::Regex::new($re) { - Ok(re) => re, - Err(err) => panic!("{}", err), - } - ); + ($re:expr) => {{ ::regex::Regex::new($re).unwrap() }} ); mod bench; +mod bench_dynamic_compile; +mod bench_dynamic_parse; +mod bench_sherlock; diff --git a/benches/bench_dynamic_compile.rs b/benches/bench_dynamic_compile.rs new file mode 100644 index 0000000000..17ab319b30 --- /dev/null +++ b/benches/bench_dynamic_compile.rs @@ -0,0 +1,61 @@ +// Copyright 2014 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +use test::Bencher; + +use regex::internal::ProgramBuilder; + +#[bench] +fn compile_simple(b: &mut Bencher) { + b.iter(|| { + let re = r"^bc(d|e)*$"; + ProgramBuilder::new(&re).compile().unwrap() + }); +} + +#[bench] +fn compile_simple_bytes(b: &mut Bencher) { + b.iter(|| { + let re = r"^bc(d|e)*$"; + ProgramBuilder::new(&re).bytes(true).compile().unwrap() + }); +} + +#[bench] +fn compile_small(b: &mut Bencher) { + b.iter(|| { + let re = r"\p{L}|\p{N}|\s|.|\d"; + ProgramBuilder::new(&re).compile().unwrap() + }); +} + +#[bench] +fn compile_small_bytes(b: &mut Bencher) { + b.iter(|| { + let re = r"\p{L}|\p{N}|\s|.|\d"; + ProgramBuilder::new(&re).bytes(true).compile().unwrap() + }); +} + +#[bench] +fn compile_huge(b: &mut Bencher) { + b.iter(|| { + let re = r"\p{L}{100}"; + ProgramBuilder::new(&re).compile().unwrap() + }); +} + +#[bench] +fn compile_huge_bytes(b: &mut Bencher) { + b.iter(|| { + let re = r"\p{L}{100}"; + ProgramBuilder::new(&re).bytes(true).compile().unwrap() + }); +} diff --git a/benches/bench_dynamic_nfa.rs b/benches/bench_dynamic_nfa.rs new file mode 100644 index 0000000000..8c026ec778 --- /dev/null +++ b/benches/bench_dynamic_nfa.rs @@ -0,0 +1,32 @@ +// Copyright 2014 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +#![feature(test)] + +#[macro_use] extern crate lazy_static; +extern crate rand; +extern crate regex; +extern crate regex_syntax; +extern crate test; + +// Due to macro scoping rules, this definition only applies for the modules +// defined below. Effectively, it allows us to use the same tests for both +// native and dynamic regexes. +macro_rules! regex( + ($re:expr) => {{ + use regex::internal::ExecBuilder; + ExecBuilder::new($re).nfa().build().unwrap().into_regex() + }} +); + +mod bench; +mod bench_dynamic_compile; +mod bench_dynamic_parse; +mod bench_sherlock; diff --git a/benches/bench_dynamic_parse.rs b/benches/bench_dynamic_parse.rs new file mode 100644 index 0000000000..e86e18c516 --- /dev/null +++ b/benches/bench_dynamic_parse.rs @@ -0,0 +1,36 @@ +// Copyright 2014 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +use regex_syntax::Expr; +use test::Bencher; + +#[bench] +fn parse_simple(b: &mut Bencher) { + b.iter(|| { + let re = r"^bc(d|e)*$"; + Expr::parse(re).unwrap() + }); +} + +#[bench] +fn parse_small(b: &mut Bencher) { + b.iter(|| { + let re = r"\p{L}|\p{N}|\s|.|\d"; + Expr::parse(re).unwrap() + }); +} + +#[bench] +fn parse_huge(b: &mut Bencher) { + b.iter(|| { + let re = r"\p{L}{100}"; + Expr::parse(re).unwrap() + }); +} diff --git a/regex_macros/benches/bench_native.rs b/benches/bench_native.rs similarity index 87% rename from regex_macros/benches/bench_native.rs rename to benches/bench_native.rs index a7b07cabe3..c1766991e7 100644 --- a/regex_macros/benches/bench_native.rs +++ b/benches/bench_native.rs @@ -11,8 +11,11 @@ #![feature(plugin, test)] #![plugin(regex_macros)] +#[macro_use] extern crate lazy_static; extern crate rand; extern crate regex; +extern crate regex_syntax; extern crate test; mod bench; +mod bench_sherlock; diff --git a/benches/bench_pcre.rs b/benches/bench_pcre.rs new file mode 100644 index 0000000000..069782b484 --- /dev/null +++ b/benches/bench_pcre.rs @@ -0,0 +1,308 @@ +// Copyright 2014 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +// These benchmarks use PCRE to reproduce some of the benchmarks used to track +// performance of regexes in this crate. I'm not an experienced user of PCRE, +// so it's possible that usage here is not optimal. If it isn't, then +// improvements are welcome. (I'm aware that PCRE has a DFA, but it doesn't +// seem to actually preserve leftmost-first semantics, like the DFA in this +// crate does.) +// +// Note that for these benchmarks, all we need is to detect whether there is +// a match or not. + +#![feature(test)] +#![allow(non_snake_case)] + +extern crate enum_set; +#[macro_use] extern crate lazy_static; +extern crate pcre; +extern crate rand; +extern crate regex; +extern crate regex_syntax; +extern crate test; + +use std::iter::repeat; + +use rand::{Rng, thread_rng}; +use test::Bencher; + +/// A nominal wrapper around pcre::Pcre to expose an interface similar to +/// regex::Regex. +struct RegexPcre(pcre::Pcre); + +/// lazy_static wants this. No reason not to provide it. +unsafe impl Send for RegexPcre {} +unsafe impl Sync for RegexPcre {} + +impl RegexPcre { + fn is_match(&mut self, text: &str) -> bool { + self.0.exec(text).is_some() + } + + fn count_matches(&mut self, text: &str) -> usize { + self.0.matches(text).count() + } +} + +macro_rules! regex( + ($re:expr) => {{ + use enum_set::EnumSet; + use pcre::{Pcre, CompileOption, StudyOption}; + + let mut comp_opts = EnumSet::new(); + // Rust's regex library exclusively uses Unicode-aware character + // classes. + comp_opts.insert(CompileOption::Ucp); + let mut re = Pcre::compile_with_options($re, &comp_opts).unwrap(); + + let mut study_opts = EnumSet::new(); + study_opts.insert(StudyOption::StudyJitCompile); + re.study_with_options(&study_opts); + + ::RegexPcre(re) + }} +); + +macro_rules! bench_match { + ($name:ident, $re:expr, $text:expr) => { + #[bench] + fn $name(b: &mut Bencher) { + use std::sync::Mutex; + + lazy_static! { + static ref RE: Mutex = Mutex::new($re); + static ref TEXT: String = $text; + }; + let mut re = RE.lock().unwrap(); + b.bytes = TEXT.len() as u64; + b.iter(|| { + if !re.is_match(&TEXT) { + panic!("expected match, got not match"); + } + }); + } + } +} + +macro_rules! bench_nomatch { + ($name:ident, $re:expr, $text:expr) => { + #[bench] + fn $name(b: &mut Bencher) { + use std::sync::Mutex; + + lazy_static! { + static ref RE: Mutex = Mutex::new($re); + static ref TEXT: String = $text; + }; + let mut re = RE.lock().unwrap(); + b.bytes = TEXT.len() as u64; + b.iter(|| { + if re.is_match(&TEXT) { + panic!("match not expected"); + } + }); + } + } +} + +bench_match!(literal, regex!("y"), { + format!("{}y", repeat("x").take(50).collect::()) +}); + +bench_match!(not_literal, regex!(".y"), { + format!("{}y", repeat("x").take(50).collect::()) +}); + +bench_match!(match_class, regex!("[abcdw]"), { + format!("{}w", repeat("xxxx").take(20).collect::()) +}); + +bench_match!(match_class_in_range, regex!("[ac]"), { + format!("{}c", repeat("bbbb").take(20).collect::()) +}); + +bench_match!(match_class_unicode, regex!(r"\pL"), { + format!("{}a", repeat("☃5☃5").take(20).collect::()) +}); + +bench_nomatch!(anchored_literal_short_non_match, regex!("^zbc(d|e)"), { + "abcdefghijklmnopqrstuvwxyz".to_owned() +}); + +bench_nomatch!(anchored_literal_long_non_match, regex!("^zbc(d|e)"), { + repeat("abcdefghijklmnopqrstuvwxyz").take(15).collect::() +}); + +bench_match!(anchored_literal_short_match, regex!("^.bc(d|e)"), { + "abcdefghijklmnopqrstuvwxyz".to_owned() +}); + +bench_match!(anchored_literal_long_match, regex!("^.bc(d|e)"), { + repeat("abcdefghijklmnopqrstuvwxyz").take(15).collect::() +}); + +bench_match!(one_pass_short, regex!("^.bc(d|e)*$"), { + "abcddddddeeeededd".to_owned() +}); + +bench_match!(one_pass_short_not, regex!(".bc(d|e)*$"), { + "abcddddddeeeededd".to_owned() +}); + +bench_match!(one_pass_long_prefix, regex!("^abcdefghijklmnopqrstuvwxyz.*$"), { + "abcdefghijklmnopqrstuvwxyz".to_owned() +}); + +bench_match!(one_pass_long_prefix_not, regex!("^.bcdefghijklmnopqrstuvwxyz.*$"), { + "abcdefghijklmnopqrstuvwxyz".to_owned() +}); + +fn gen_text(n: usize) -> String { + let mut rng = thread_rng(); + let mut bytes = rng.gen_ascii_chars().map(|n| n as u8).take(n) + .collect::>(); + for (i, b) in bytes.iter_mut().enumerate() { + if i % 20 == 0 { + *b = b'\n' + } + } + String::from_utf8(bytes).unwrap() +} + +fn easy0() -> RegexPcre { + regex!("ABCDEFGHIJKLMNOPQRSTUVWXYZ$") +} + +bench_nomatch!(easy0_32, easy0(), gen_text(32)); +bench_nomatch!(easy0_1K, easy0(), gen_text(1<<10)); +bench_nomatch!(easy0_32K, easy0(), gen_text(32<<10)); +bench_nomatch!(easy0_1MB, easy0(), gen_text(1<<20)); + +fn easy1() -> RegexPcre { + regex!("A[AB]B[BC]C[CD]D[DE]E[EF]F[FG]G[GH]H[HI]I[IJ]J$") +} + +bench_nomatch!(easy1_32, easy1(), gen_text(32)); +bench_nomatch!(easy1_1K, easy1(), gen_text(1<<10)); +bench_nomatch!(easy1_32K, easy1(), gen_text(32<<10)); +bench_nomatch!(easy1_1MB, easy1(), gen_text(1<<20)); + +fn medium() -> RegexPcre { + regex!("[XYZ]ABCDEFGHIJKLMNOPQRSTUVWXYZ$") +} + +bench_nomatch!(medium_32, medium(), gen_text(32)); +bench_nomatch!(medium_1K, medium(), gen_text(1<<10)); +bench_nomatch!(medium_32K, medium(), gen_text(32<<10)); +bench_nomatch!(medium_1MB, medium(), gen_text(1<<20)); + +fn hard() -> RegexPcre { + regex!("[ -~]*ABCDEFGHIJKLMNOPQRSTUVWXYZ$") +} + +bench_nomatch!(hard_32, hard(), gen_text(32)); +bench_nomatch!(hard_1K, hard(), gen_text(1<<10)); +bench_nomatch!(hard_32K, hard(), gen_text(32<<10)); +bench_nomatch!(hard_1MB, hard(), gen_text(1<<20)); + + +// These are the Sherlock Holmes benchmarks. Not all of them are present +// since the syntax isn't exactly the same for things like case insensitive +// matching. We could add them back by twiddling the flags using PCRE though. +// +// Other benchmarks are removed purely because PCRE is too darn slow on them. + +mod sherlock { + use super::RegexPcre; + use test::Bencher; + + lazy_static! { + static ref SHERLOCK: String = { + include_str!("the-adventures-of-sherlock-holmes.txt").to_owned() + }; + } + + macro_rules! bench_find { + ($name:ident, $re:expr, $count:expr) => { + #[bench] + fn $name(b: &mut Bencher) { + use std::sync::Mutex; + + lazy_static! { + static ref RE: Mutex = Mutex::new($re); + }; + let mut re = RE.lock().unwrap(); + b.bytes = SHERLOCK.len() as u64; + b.iter(|| { + let count = re.count_matches(&SHERLOCK); + assert_eq!($count, count) + }); + } + } + } + + bench_find!(name_sherlock, regex!("Sherlock"), 97); + bench_find!(name_holmes, regex!("Holmes"), 461); + bench_find!(name_sherlock_holmes, regex!("Sherlock Holmes"), 91); + + bench_find!(name_sherlock_nocase, regex!("(?i)Sherlock"), 102); + bench_find!(name_holmes_nocase, regex!("(?i)Holmes"), 467); + bench_find!( + name_sherlock_holmes_nocase, regex!("(?i)Sherlock Holmes"), 96); + + bench_find!(name_whitespace, regex!(r"Sherlock\s+Holmes"), 97); + + bench_find!(name_alt1, regex!("Sherlock|Street"), 158); + bench_find!(name_alt2, regex!("Sherlock|Holmes"), 558); + bench_find!( + name_alt3, + regex!("Sherlock|Holmes|Watson|Irene|Adler|John|Baker"), 740); + bench_find!( + name_alt3_nocase, + regex!("(?i)Sherlock|Holmes|Watson|Irene|Adler|John|Baker"), 753); + bench_find!(name_alt4, regex!("Sher[a-z]+|Hol[a-z]+"), 582); + bench_find!(name_alt4_nocase, regex!("(?i)Sher[a-z]+|Hol[a-z]+"), 697); + + bench_find!(no_match_uncommon, regex!("zyx"), 0); + bench_find!(no_match_common, regex!("ayx"), 0); + + bench_find!(the_lower, regex!("the"), 7218); + bench_find!(the_upper, regex!("The"), 741); + bench_find!(the_nocase, regex!("(?i)the"), 7987); + + // bench_find!(everything_greedy, regex!(".*"), 13053); + // bench_find!(everything_greedy_nl, regex!("(?s).*"), 1); + + bench_find!(letters, regex!(r"\pL"), 447160); + bench_find!(letters_upper, regex!(r"\p{Lu}"), 14180); + bench_find!(letters_lower, regex!(r"\p{Ll}"), 432980); + + bench_find!(words, regex!(r"\w+"), 109214); + + bench_find!(the_whitespace, regex!(r"the\s+\w+"), 5410); + + bench_find!(before_holmes, regex!(r"\w+\s+Holmes"), 319); + + bench_find!(holmes_cochar_watson, + regex!(r"Holmes.{0,25}Watson|Watson.{0,25}Holmes"), 7); + + // bench_find!( + // holmes_coword_watson, + // regex!(r"Holmes(?:\s*.+\s*){0,10}Watson|Watson(?:\s*.+\s*){0,10}Holmes"), + // 64); + + bench_find!(quotes, regex!(r#"["'][^"']{0,30}[?!.]["']"#), 767); + + bench_find!(line_boundary_sherlock_holmes, + regex!(r"(?m)^Sherlock Holmes|Sherlock Holmes$"), 34); + + bench_find!(word_ending_n, regex!(r"\b\w+n\b"), 8366); +} diff --git a/benches/bench_sherlock.rs b/benches/bench_sherlock.rs new file mode 100644 index 0000000000..308b4c82d0 --- /dev/null +++ b/benches/bench_sherlock.rs @@ -0,0 +1,138 @@ +// Copyright 2014 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +use regex::Regex; +use test::Bencher; + +lazy_static! { + static ref SHERLOCK: String = { + include_str!("the-adventures-of-sherlock-holmes.txt").to_owned() + }; +} + +macro_rules! bench_find { + ($name:ident, $re:expr, $count:expr) => { + #[bench] + fn $name(b: &mut Bencher) { + lazy_static! { + static ref RE: Regex = $re; + }; + b.bytes = SHERLOCK.len() as u64; + b.iter(|| { + let count = RE.find_iter(&SHERLOCK).count(); + assert_eq!($count, count) + }); + } + } +} + +// These patterns are all single string literals that compile down to a variant +// of Boyer-Moore w/ memchr. This also demonstrates the impact that the +// frequency of a match has on performance. +bench_find!(name_sherlock, regex!("Sherlock"), 97); +bench_find!(name_holmes, regex!("Holmes"), 461); +bench_find!(name_sherlock_holmes, regex!("Sherlock Holmes"), 91); + +// Like the above, except case insensitively. +// The prefix finder is broken at the moment, so these are probably a touch +// slower than they should be. +bench_find!(name_sherlock_nocase, regex!("(?i)Sherlock"), 102); +bench_find!(name_holmes_nocase, regex!("(?i)Holmes"), 467); +bench_find!(name_sherlock_holmes_nocase, regex!("(?i)Sherlock Holmes"), 96); + +// Will quickly find instances of 'Sherlock', but then needs to fall back to +// the lazy DFA to process the Unicode aware `\s`. +bench_find!(name_whitespace, regex!(r"Sherlock\s+Holmes"), 97); + +// Now try more variations on name matching. +// This one has two alternates that both start with 'S'. This should compile +// to an Aho-Corasick automaton that uses memchr. Never enters lazy DFA. +bench_find!(name_alt1, regex!("Sherlock|Street"), 158); +// This one doesn't have a common byte, but should still use Aho-Corasick. +// Never enters lazy DFA. +bench_find!(name_alt2, regex!("Sherlock|Holmes"), 558); +// OK, still using Aho-Corasick, but more patterns. Never enters lazy DFA. +bench_find!( + name_alt3, + regex!("Sherlock|Holmes|Watson|Irene|Adler|John|Baker"), 740); +// Still using Aho-Corasick, but needs the lazy DFA. +bench_find!( + name_alt3_nocase, + regex!("(?i)Sherlock|Holmes|Watson|Irene|Adler|John|Baker"), 753); +// Should still use Aho-Corasick for the prefixes in each alternate, but +// we need to use the lazy DFA to complete it. +bench_find!(name_alt4, regex!("Sher[a-z]+|Hol[a-z]+"), 582); +bench_find!(name_alt4_nocase, regex!("(?i)Sher[a-z]+|Hol[a-z]+"), 697); + +// How long does it take to discover that there's no match? +// If it starts with an uncommon character, then not long at all. +// A common character? It might be 25x slower! +bench_find!(no_match_uncommon, regex!("zyx"), 0); +bench_find!(no_match_common, regex!("ayx"), 0); + +// Various twiddling on very common words. +bench_find!(the_lower, regex!("the"), 7218); +bench_find!(the_upper, regex!("The"), 741); +bench_find!(the_nocase, regex!("(?i)the"), 7987); + +// How fast can we match everything? This essentially defeats any clever prefix +// tricks and just executes the DFA across the entire input. +bench_find!(everything_greedy, regex!(".*"), 13053); +bench_find!(everything_greedy_nl, regex!("(?s).*"), 1); + +// How fast can we match every letter? This also defeats any clever prefix +// tricks. +bench_find!(letters, regex!(r"\pL"), 447160); +bench_find!(letters_upper, regex!(r"\p{Lu}"), 14180); +bench_find!(letters_lower, regex!(r"\p{Ll}"), 432980); + +// Similarly, for words. +bench_find!(words, regex!(r"\w+"), 109214); + +// Process whitespace after a very common word. +// Uses Boyer-Moore to find `the` and the lazy DFA for the rest. +bench_find!(the_whitespace, regex!(r"the\s+\w+"), 5410); + +// Find complete words before Holmes. The `\w` defeats any prefix +// optimizations, so it's the lazy DFA the entire way. +bench_find!(before_holmes, regex!(r"\w+\s+Holmes"), 319); + +// Find Holmes co-occuring with Watson in a particular window of characters. +// This uses Aho-Corasick for the Holmes|Watson prefix, but the lazy DFA for +// the rest. +bench_find!( + holmes_cochar_watson, + regex!(r"Holmes.{0,25}Watson|Watson.{0,25}Holmes"), 7); + +// Find Holmes co-occuring with Watson in a particular window of words. +// This uses Aho-Corasick for the Holmes|Watson prefix, but the lazy DFA for +// the rest. +bench_find!( + holmes_coword_watson, + regex!(r"Holmes(?:\s*.+\s*){0,10}Watson|Watson(?:\s*.+\s*){0,10}Holmes"), + 51); + +// Find some subset of quotes in the text. +// This does detect the `"` or `'` prefix literal and does a quick scan for +// either byte before starting the lazy DFA. +bench_find!(quotes, regex!(r#"["'][^"']{0,30}[?!.]["']"#), 767); + +// Finds all occurrences of Sherlock Holmes at the beginning or end of a line. +// The empty assertions defeat any detection of prefix literals, so it's the +// lazy DFA the entire way. +bench_find!( + line_boundary_sherlock_holmes, + regex!(r"(?m)^Sherlock Holmes|Sherlock Holmes$"), 34); + +// All words ending in `n`. +// This uses word boundaries, which the lazy DFA cannot handle. Since the word +// boundary also defeats finding any literal prefixes, we have to use the +// NFA algorithm the whole way. +bench_find!(word_ending_n, regex!(r"\b\w+n\b"), 8366); diff --git a/benches/log/01-lazy-dfa/dynamic b/benches/log/01-lazy-dfa/dynamic new file mode 100644 index 0000000000..9ef21737d0 --- /dev/null +++ b/benches/log/01-lazy-dfa/dynamic @@ -0,0 +1,73 @@ + Running target/release/dynamic-e87a67d7ea67f0eb + +running 67 tests +test bench::anchored_literal_long_match ... bench: 75 ns/iter (+/- 3) = 5200 MB/s +test bench::anchored_literal_long_non_match ... bench: 61 ns/iter (+/- 2) = 6393 MB/s +test bench::anchored_literal_short_match ... bench: 75 ns/iter (+/- 3) = 346 MB/s +test bench::anchored_literal_short_non_match ... bench: 61 ns/iter (+/- 1) = 426 MB/s +test bench::easy0_1K ... bench: 196 ns/iter (+/- 8) = 5224 MB/s +test bench::easy0_1MB ... bench: 255,138 ns/iter (+/- 4,820) = 4109 MB/s +test bench::easy0_32 ... bench: 71 ns/iter (+/- 2) = 450 MB/s +test bench::easy0_32K ... bench: 5,392 ns/iter (+/- 108) = 6077 MB/s +test bench::easy1_1K ... bench: 241 ns/iter (+/- 37) = 4248 MB/s +test bench::easy1_1MB ... bench: 334,872 ns/iter (+/- 3,433) = 3131 MB/s +test bench::easy1_32 ... bench: 65 ns/iter (+/- 2) = 492 MB/s +test bench::easy1_32K ... bench: 6,139 ns/iter (+/- 703) = 5337 MB/s +test bench::hard_1K ... bench: 4,654 ns/iter (+/- 63) = 220 MB/s +test bench::hard_1MB ... bench: 4,719,487 ns/iter (+/- 71,818) = 222 MB/s +test bench::hard_32 ... bench: 199 ns/iter (+/- 8) = 160 MB/s +test bench::hard_32K ... bench: 147,389 ns/iter (+/- 4,391) = 222 MB/s +test bench::literal ... bench: 20 ns/iter (+/- 4) = 2550 MB/s +test bench::match_class ... bench: 85 ns/iter (+/- 4) = 952 MB/s +test bench::match_class_in_range ... bench: 32 ns/iter (+/- 3) = 2531 MB/s +test bench::match_class_unicode ... bench: 783 ns/iter (+/- 13) = 205 MB/s +test bench::medium_1K ... bench: 1,334 ns/iter (+/- 154) = 767 MB/s +test bench::medium_1MB ... bench: 2,044,757 ns/iter (+/- 72,936) = 512 MB/s +test bench::medium_32 ... bench: 99 ns/iter (+/- 18) = 323 MB/s +test bench::medium_32K ... bench: 59,603 ns/iter (+/- 13,750) = 549 MB/s +test bench::no_exponential ... bench: 553 ns/iter (+/- 150) = 180 MB/s +test bench::not_literal ... bench: 293 ns/iter (+/- 59) = 174 MB/s +test bench::one_pass_long_prefix ... bench: 177 ns/iter (+/- 35) = 146 MB/s +test bench::one_pass_long_prefix_not ... bench: 175 ns/iter (+/- 47) = 148 MB/s +test bench::one_pass_short ... bench: 134 ns/iter (+/- 34) = 126 MB/s +test bench::one_pass_short_not ... bench: 136 ns/iter (+/- 39) = 125 MB/s +test bench::replace_all ... bench: 153 ns/iter (+/- 17) +test bench_dynamic_compile::compile_huge ... bench: 165,209 ns/iter (+/- 4,396) +test bench_dynamic_compile::compile_huge_bytes ... bench: 18,795,770 ns/iter (+/- 2,674,909) +test bench_dynamic_compile::compile_simple ... bench: 6,883 ns/iter (+/- 391) +test bench_dynamic_compile::compile_simple_bytes ... bench: 7,281 ns/iter (+/- 751) +test bench_dynamic_compile::compile_small ... bench: 9,091 ns/iter (+/- 1,125) +test bench_dynamic_compile::compile_small_bytes ... bench: 182,815 ns/iter (+/- 3,814) +test bench_dynamic_parse::parse_huge ... bench: 1,233 ns/iter (+/- 123) +test bench_dynamic_parse::parse_simple ... bench: 2,015 ns/iter (+/- 108) +test bench_dynamic_parse::parse_small ... bench: 2,500 ns/iter (+/- 76) +test bench_sherlock::before_holmes ... bench: 2,741,811 ns/iter (+/- 58,389) = 216 MB/s +test bench_sherlock::everything_greedy ... bench: 7,807,696 ns/iter (+/- 328,585) = 76 MB/s +test bench_sherlock::everything_greedy_nl ... bench: 5,424,922 ns/iter (+/- 78,937) = 109 MB/s +test bench_sherlock::holmes_cochar_watson ... bench: 266,557 ns/iter (+/- 3,832) = 2231 MB/s +test bench_sherlock::holmes_coword_watson ... bench: 1,327,967 ns/iter (+/- 12,773) = 448 MB/s +test bench_sherlock::line_boundary_sherlock_holmes ... bench: 2,690,485 ns/iter (+/- 17,393) = 221 MB/s +test bench_sherlock::name_alt1 ... bench: 77,206 ns/iter (+/- 951) = 7705 MB/s +test bench_sherlock::name_alt2 ... bench: 303,775 ns/iter (+/- 5,030) = 1958 MB/s +test bench_sherlock::name_alt3 ... bench: 1,385,153 ns/iter (+/- 15,871) = 429 MB/s +test bench_sherlock::name_alt3_nocase ... bench: 1,473,833 ns/iter (+/- 9,825) = 403 MB/s +test bench_sherlock::name_alt4 ... bench: 300,912 ns/iter (+/- 3,896) = 1977 MB/s +test bench_sherlock::name_alt4_nocase ... bench: 1,421,519 ns/iter (+/- 16,246) = 418 MB/s +test bench_sherlock::name_holmes ... bench: 52,027 ns/iter (+/- 785) = 11435 MB/s +test bench_sherlock::name_holmes_nocase ... bench: 1,241,204 ns/iter (+/- 16,862) = 479 MB/s +test bench_sherlock::name_sherlock ... bench: 34,378 ns/iter (+/- 677) = 17305 MB/s +test bench_sherlock::name_sherlock_holmes ... bench: 34,463 ns/iter (+/- 580) = 17262 MB/s +test bench_sherlock::name_sherlock_holmes_nocase ... bench: 1,281,540 ns/iter (+/- 11,054) = 464 MB/s +test bench_sherlock::name_sherlock_nocase ... bench: 1,281,293 ns/iter (+/- 13,129) = 464 MB/s +test bench_sherlock::name_whitespace ... bench: 60,463 ns/iter (+/- 815) = 9839 MB/s +test bench_sherlock::no_match_common ... bench: 568,357 ns/iter (+/- 11,237) = 1046 MB/s +test bench_sherlock::no_match_uncommon ... bench: 23,656 ns/iter (+/- 340) = 25149 MB/s +test bench_sherlock::quotes ... bench: 977,907 ns/iter (+/- 13,926) = 608 MB/s +test bench_sherlock::the_lower ... bench: 794,285 ns/iter (+/- 8,513) = 749 MB/s +test bench_sherlock::the_nocase ... bench: 1,837,240 ns/iter (+/- 22,738) = 323 MB/s +test bench_sherlock::the_upper ... bench: 54,083 ns/iter (+/- 1,153) = 11000 MB/s +test bench_sherlock::the_whitespace ... bench: 1,986,579 ns/iter (+/- 9,292) = 299 MB/s +test bench_sherlock::word_ending_n ... bench: 55,205,101 ns/iter (+/- 93,542) = 10 MB/s + +test result: ok. 0 passed; 0 failed; 0 ignored; 67 measured + diff --git a/benches/log/01-lazy-dfa/dynamic-no-lazy-dfa b/benches/log/01-lazy-dfa/dynamic-no-lazy-dfa new file mode 100644 index 0000000000..50d3a136c3 --- /dev/null +++ b/benches/log/01-lazy-dfa/dynamic-no-lazy-dfa @@ -0,0 +1,85 @@ + Compiling regex v0.1.48 (file:///home/andrew/data/projects/rust/regex) +src/dfa.rs:73:1: 94:2 warning: function is never used: `can_exec`, #[warn(dead_code)] on by default +src/dfa.rs:73 pub fn can_exec(insts: &Insts) -> bool { +src/dfa.rs:74 use inst::EmptyLook::*; +src/dfa.rs:75 // If for some reason we manage to allocate a regex program with more +src/dfa.rs:76 // than 2^32-1 instructions, then we can't execute the DFA because we +src/dfa.rs:77 // use 32 bit pointers. +src/dfa.rs:78 if insts.len() > ::std::u32::MAX as usize { + ... +src/exec.rs:12:11: 12:15 warning: unused import, #[warn(unused_imports)] on by default +src/exec.rs:12 use dfa::{self, Dfa, DfaResult}; + ^~~~ + Running target/release/dynamic-e87a67d7ea67f0eb + +running 67 tests +test bench::anchored_literal_long_match ... bench: 169 ns/iter (+/- 1) = 2307 MB/s +test bench::anchored_literal_long_non_match ... bench: 85 ns/iter (+/- 0) = 4588 MB/s +test bench::anchored_literal_short_match ... bench: 158 ns/iter (+/- 3) = 164 MB/s +test bench::anchored_literal_short_non_match ... bench: 84 ns/iter (+/- 2) = 309 MB/s +test bench::easy0_1K ... bench: 318 ns/iter (+/- 2) = 3220 MB/s +test bench::easy0_1MB ... bench: 257,205 ns/iter (+/- 2,448) = 4076 MB/s +test bench::easy0_32 ... bench: 82 ns/iter (+/- 1) = 390 MB/s +test bench::easy0_32K ... bench: 8,666 ns/iter (+/- 104) = 3781 MB/s +test bench::easy1_1K ... bench: 293 ns/iter (+/- 2) = 3494 MB/s +test bench::easy1_1MB ... bench: 329,774 ns/iter (+/- 6,296) = 3179 MB/s +test bench::easy1_32 ... bench: 77 ns/iter (+/- 0) = 415 MB/s +test bench::easy1_32K ... bench: 8,856 ns/iter (+/- 93) = 3700 MB/s +test bench::hard_1K ... bench: 31,888 ns/iter (+/- 83) = 32 MB/s +test bench::hard_1MB ... bench: 58,435,108 ns/iter (+/- 64,537) = 17 MB/s +test bench::hard_32 ... bench: 1,048 ns/iter (+/- 12) = 30 MB/s +test bench::hard_32K ... bench: 1,033,930 ns/iter (+/- 4,224) = 31 MB/s +test bench::literal ... bench: 20 ns/iter (+/- 0) = 2550 MB/s +test bench::match_class ... bench: 84 ns/iter (+/- 0) = 964 MB/s +test bench::match_class_in_range ... bench: 33 ns/iter (+/- 0) = 2454 MB/s +test bench::match_class_unicode ... bench: 2,218 ns/iter (+/- 8) = 72 MB/s +test bench::medium_1K ... bench: 1,368 ns/iter (+/- 9) = 748 MB/s +test bench::medium_1MB ... bench: 2,034,481 ns/iter (+/- 3,608) = 515 MB/s +test bench::medium_32 ... bench: 141 ns/iter (+/- 0) = 226 MB/s +test bench::medium_32K ... bench: 59,949 ns/iter (+/- 421) = 546 MB/s +test bench::no_exponential ... bench: 336,653 ns/iter (+/- 1,757) +test bench::not_literal ... bench: 1,247 ns/iter (+/- 5) = 40 MB/s +test bench::one_pass_long_prefix ... bench: 264 ns/iter (+/- 2) = 98 MB/s +test bench::one_pass_long_prefix_not ... bench: 267 ns/iter (+/- 1) = 97 MB/s +test bench::one_pass_short ... bench: 768 ns/iter (+/- 5) = 22 MB/s +test bench::one_pass_short_not ... bench: 797 ns/iter (+/- 20) = 21 MB/s +test bench::replace_all ... bench: 149 ns/iter (+/- 0) +test bench_dynamic_compile::compile_huge ... bench: 161,349 ns/iter (+/- 1,462) +test bench_dynamic_compile::compile_huge_bytes ... bench: 18,050,519 ns/iter (+/- 105,846) +test bench_dynamic_compile::compile_simple ... bench: 6,664 ns/iter (+/- 390) +test bench_dynamic_compile::compile_simple_bytes ... bench: 7,035 ns/iter (+/- 370) +test bench_dynamic_compile::compile_small ... bench: 8,914 ns/iter (+/- 347) +test bench_dynamic_compile::compile_small_bytes ... bench: 186,970 ns/iter (+/- 2,134) +test bench_dynamic_parse::parse_huge ... bench: 1,238 ns/iter (+/- 11) +test bench_dynamic_parse::parse_simple ... bench: 2,005 ns/iter (+/- 19) +test bench_dynamic_parse::parse_small ... bench: 2,494 ns/iter (+/- 11) +test bench_sherlock::before_holmes ... bench: 42,005,594 ns/iter (+/- 57,752) = 14 MB/s +test bench_sherlock::everything_greedy ... bench: 38,431,063 ns/iter (+/- 28,840) = 15 MB/s +test bench_sherlock::everything_greedy_nl ... bench: 32,003,966 ns/iter (+/- 50,270) = 18 MB/s +test bench_sherlock::holmes_cochar_watson ... bench: 1,457,068 ns/iter (+/- 3,202) = 408 MB/s +test bench_sherlock::holmes_coword_watson ... bench: 136,035,549 ns/iter (+/- 75,381) = 4 MB/s +test bench_sherlock::line_boundary_sherlock_holmes ... bench: 33,024,291 ns/iter (+/- 67,902) = 18 MB/s +test bench_sherlock::name_alt1 ... bench: 157,989 ns/iter (+/- 917) = 3765 MB/s +test bench_sherlock::name_alt2 ... bench: 545,254 ns/iter (+/- 1,908) = 1091 MB/s +test bench_sherlock::name_alt3 ... bench: 2,245,964 ns/iter (+/- 2,478) = 264 MB/s +test bench_sherlock::name_alt3_nocase ... bench: 4,792,290 ns/iter (+/- 31,760) = 124 MB/s +test bench_sherlock::name_alt4 ... bench: 584,204 ns/iter (+/- 2,084) = 1018 MB/s +test bench_sherlock::name_alt4_nocase ... bench: 2,318,020 ns/iter (+/- 8,493) = 256 MB/s +test bench_sherlock::name_holmes ... bench: 51,880 ns/iter (+/- 299) = 11467 MB/s +test bench_sherlock::name_holmes_nocase ... bench: 1,414,500 ns/iter (+/- 2,497) = 420 MB/s +test bench_sherlock::name_sherlock ... bench: 34,294 ns/iter (+/- 349) = 17348 MB/s +test bench_sherlock::name_sherlock_holmes ... bench: 34,531 ns/iter (+/- 199) = 17228 MB/s +test bench_sherlock::name_sherlock_holmes_nocase ... bench: 1,692,651 ns/iter (+/- 8,846) = 351 MB/s +test bench_sherlock::name_sherlock_nocase ... bench: 1,657,413 ns/iter (+/- 5,534) = 358 MB/s +test bench_sherlock::name_whitespace ... bench: 131,372 ns/iter (+/- 605) = 4528 MB/s +test bench_sherlock::no_match_common ... bench: 567,065 ns/iter (+/- 2,763) = 1049 MB/s +test bench_sherlock::no_match_uncommon ... bench: 23,782 ns/iter (+/- 85) = 25016 MB/s +test bench_sherlock::quotes ... bench: 11,251,366 ns/iter (+/- 24,960) = 52 MB/s +test bench_sherlock::the_lower ... bench: 789,781 ns/iter (+/- 2,072) = 753 MB/s +test bench_sherlock::the_nocase ... bench: 1,807,509 ns/iter (+/- 4,685) = 329 MB/s +test bench_sherlock::the_upper ... bench: 53,542 ns/iter (+/- 198) = 11111 MB/s +test bench_sherlock::the_whitespace ... bench: 5,410,444 ns/iter (+/- 14,766) = 109 MB/s +test bench_sherlock::word_ending_n ... bench: 56,017,874 ns/iter (+/- 60,047) = 10 MB/s + +test result: ok. 0 passed; 0 failed; 0 ignored; 67 measured + diff --git a/benches/log/01-lazy-dfa/native b/benches/log/01-lazy-dfa/native new file mode 100644 index 0000000000..61fc08da41 --- /dev/null +++ b/benches/log/01-lazy-dfa/native @@ -0,0 +1,65 @@ + Compiling regex_macros v0.1.28 (file:///home/andrew/data/projects/rust/regex/regex_macros) + Running regex_macros/target/release/native-f2ffefeeda527264 + +running 58 tests +test bench::anchored_literal_long_match ... bench: 189 ns/iter (+/- 16) = 2063 MB/s +test bench::anchored_literal_long_non_match ... bench: 47 ns/iter (+/- 1) = 8297 MB/s +test bench::anchored_literal_short_match ... bench: 177 ns/iter (+/- 5) = 146 MB/s +test bench::anchored_literal_short_non_match ... bench: 46 ns/iter (+/- 1) = 565 MB/s +test bench::easy0_1K ... bench: 26,578 ns/iter (+/- 1,140) = 38 MB/s +test bench::easy0_1MB ... bench: 27,229,730 ns/iter (+/- 261,126) = 38 MB/s +test bench::easy0_32 ... bench: 867 ns/iter (+/- 45) = 36 MB/s +test bench::easy0_32K ... bench: 847,113 ns/iter (+/- 276,910) = 38 MB/s +test bench::easy1_1K ... bench: 23,525 ns/iter (+/- 278) = 43 MB/s +test bench::easy1_1MB ... bench: 24,075,047 ns/iter (+/- 40,396) = 43 MB/s +test bench::easy1_32 ... bench: 767 ns/iter (+/- 14) = 41 MB/s +test bench::easy1_32K ... bench: 752,730 ns/iter (+/- 9,284) = 43 MB/s +test bench::hard_1K ... bench: 44,053 ns/iter (+/- 513) = 23 MB/s +test bench::hard_1MB ... bench: 44,982,170 ns/iter (+/- 76,683) = 23 MB/s +test bench::hard_32 ... bench: 1,418 ns/iter (+/- 26) = 22 MB/s +test bench::hard_32K ... bench: 1,407,013 ns/iter (+/- 13,426) = 23 MB/s +test bench::literal ... bench: 1,202 ns/iter (+/- 16) = 42 MB/s +test bench::match_class ... bench: 2,057 ns/iter (+/- 29) = 39 MB/s +test bench::match_class_in_range ... bench: 2,060 ns/iter (+/- 34) = 39 MB/s +test bench::match_class_unicode ... bench: 12,945 ns/iter (+/- 156) = 12 MB/s +test bench::medium_1K ... bench: 27,874 ns/iter (+/- 315) = 36 MB/s +test bench::medium_1MB ... bench: 28,614,500 ns/iter (+/- 544,256) = 36 MB/s +test bench::medium_32 ... bench: 896 ns/iter (+/- 85) = 35 MB/s +test bench::medium_32K ... bench: 892,349 ns/iter (+/- 35,511) = 36 MB/s +test bench::no_exponential ... bench: 319,270 ns/iter (+/- 19,837) +test bench::not_literal ... bench: 1,477 ns/iter (+/- 104) = 34 MB/s +test bench::one_pass_long_prefix ... bench: 653 ns/iter (+/- 10) = 39 MB/s +test bench::one_pass_long_prefix_not ... bench: 651 ns/iter (+/- 6) = 39 MB/s +test bench::one_pass_short ... bench: 1,016 ns/iter (+/- 24) = 16 MB/s +test bench::one_pass_short_not ... bench: 1,588 ns/iter (+/- 28) = 10 MB/s +test bench::replace_all ... bench: 1,078 ns/iter (+/- 55) +test bench_sherlock::before_holmes ... bench: 54,264,124 ns/iter (+/- 564,692) = 10 MB/s +test bench_sherlock::everything_greedy ... bench: 22,724,158 ns/iter (+/- 44,361) = 26 MB/s +test bench_sherlock::everything_greedy_nl ... bench: 22,168,804 ns/iter (+/- 66,296) = 26 MB/s +test bench_sherlock::holmes_cochar_watson ... bench: 24,791,824 ns/iter (+/- 37,522) = 23 MB/s +test bench_sherlock::holmes_coword_watson ... bench: 885,999,793 ns/iter (+/- 39,704,278) +test bench_sherlock::line_boundary_sherlock_holmes ... bench: 25,113,805 ns/iter (+/- 672,050) = 23 MB/s +test bench_sherlock::name_alt1 ... bench: 23,382,716 ns/iter (+/- 3,696,517) = 25 MB/s +test bench_sherlock::name_alt2 ... bench: 23,585,220 ns/iter (+/- 3,724,922) = 25 MB/s +test bench_sherlock::name_alt3 ... bench: 80,283,635 ns/iter (+/- 3,165,029) = 7 MB/s +test bench_sherlock::name_alt3_nocase ... bench: 77,357,394 ns/iter (+/- 268,133) = 7 MB/s +test bench_sherlock::name_alt4 ... bench: 22,736,520 ns/iter (+/- 43,231) = 26 MB/s +test bench_sherlock::name_alt4_nocase ... bench: 26,921,524 ns/iter (+/- 140,162) = 22 MB/s +test bench_sherlock::name_holmes ... bench: 15,145,735 ns/iter (+/- 65,980) = 39 MB/s +test bench_sherlock::name_holmes_nocase ... bench: 16,285,042 ns/iter (+/- 71,956) = 36 MB/s +test bench_sherlock::name_sherlock ... bench: 16,189,653 ns/iter (+/- 99,929) = 36 MB/s +test bench_sherlock::name_sherlock_holmes ... bench: 14,975,742 ns/iter (+/- 118,052) = 39 MB/s +test bench_sherlock::name_sherlock_holmes_nocase ... bench: 16,904,928 ns/iter (+/- 201,104) = 35 MB/s +test bench_sherlock::name_sherlock_nocase ... bench: 16,335,907 ns/iter (+/- 118,725) = 36 MB/s +test bench_sherlock::name_whitespace ... bench: 14,837,905 ns/iter (+/- 52,201) = 40 MB/s +test bench_sherlock::no_match_common ... bench: 16,036,625 ns/iter (+/- 108,268) = 37 MB/s +test bench_sherlock::no_match_uncommon ... bench: 15,278,356 ns/iter (+/- 81,123) = 38 MB/s +test bench_sherlock::quotes ... bench: 21,580,801 ns/iter (+/- 198,772) = 27 MB/s +test bench_sherlock::the_lower ... bench: 16,059,120 ns/iter (+/- 160,640) = 37 MB/s +test bench_sherlock::the_nocase ... bench: 17,376,836 ns/iter (+/- 103,371) = 34 MB/s +test bench_sherlock::the_upper ... bench: 15,259,087 ns/iter (+/- 93,807) = 38 MB/s +test bench_sherlock::the_whitespace ... bench: 18,835,951 ns/iter (+/- 160,674) = 31 MB/s +test bench_sherlock::word_ending_n ... bench: 59,832,390 ns/iter (+/- 4,478,911) = 9 MB/s + +test result: ok. 0 passed; 0 failed; 0 ignored; 58 measured + diff --git a/benches/log/01-lazy-dfa/nfa b/benches/log/01-lazy-dfa/nfa new file mode 100644 index 0000000000..994137b55c --- /dev/null +++ b/benches/log/01-lazy-dfa/nfa @@ -0,0 +1,74 @@ + Compiling regex v0.1.48 (file:///home/andrew/data/projects/rust/regex) + Running target/release/dynamic_nfa-1e40ce11bcb7c666 + +running 67 tests +test bench::anchored_literal_long_match ... bench: 306 ns/iter (+/- 6) = 1274 MB/s +test bench::anchored_literal_long_non_match ... bench: 95 ns/iter (+/- 1) = 4105 MB/s +test bench::anchored_literal_short_match ... bench: 315 ns/iter (+/- 2) = 82 MB/s +test bench::anchored_literal_short_non_match ... bench: 96 ns/iter (+/- 2) = 270 MB/s +test bench::easy0_1K ... bench: 206 ns/iter (+/- 1) = 4970 MB/s +test bench::easy0_1MB ... bench: 255,834 ns/iter (+/- 1,273) = 4098 MB/s +test bench::easy0_32 ... bench: 72 ns/iter (+/- 2) = 444 MB/s +test bench::easy0_32K ... bench: 5,315 ns/iter (+/- 25) = 6165 MB/s +test bench::easy1_1K ... bench: 274 ns/iter (+/- 0) = 3737 MB/s +test bench::easy1_1MB ... bench: 337,047 ns/iter (+/- 1,972) = 3111 MB/s +test bench::easy1_32 ... bench: 76 ns/iter (+/- 2) = 421 MB/s +test bench::easy1_32K ... bench: 6,111 ns/iter (+/- 39) = 5362 MB/s +test bench::hard_1K ... bench: 59,596 ns/iter (+/- 264) = 17 MB/s +test bench::hard_1MB ... bench: 58,947,188 ns/iter (+/- 205,874) = 17 MB/s +test bench::hard_32 ... bench: 1,978 ns/iter (+/- 22) = 16 MB/s +test bench::hard_32K ... bench: 1,846,347 ns/iter (+/- 14,253) = 17 MB/s +test bench::literal ... bench: 172 ns/iter (+/- 1) = 296 MB/s +test bench::match_class ... bench: 240 ns/iter (+/- 1) = 337 MB/s +test bench::match_class_in_range ... bench: 190 ns/iter (+/- 2) = 426 MB/s +test bench::match_class_unicode ... bench: 4,145 ns/iter (+/- 24) = 38 MB/s +test bench::medium_1K ... bench: 1,195 ns/iter (+/- 8) = 856 MB/s +test bench::medium_1MB ... bench: 2,028,649 ns/iter (+/- 11,235) = 516 MB/s +test bench::medium_32 ... bench: 84 ns/iter (+/- 0) = 380 MB/s +test bench::medium_32K ... bench: 56,134 ns/iter (+/- 369) = 583 MB/s +test bench::no_exponential ... bench: 536 ns/iter (+/- 4) = 186 MB/s +test bench::not_literal ... bench: 2,428 ns/iter (+/- 31) = 21 MB/s +test bench::one_pass_long_prefix ... bench: 756 ns/iter (+/- 2) = 34 MB/s +test bench::one_pass_long_prefix_not ... bench: 756 ns/iter (+/- 12) = 34 MB/s +test bench::one_pass_short ... bench: 1,813 ns/iter (+/- 5) = 9 MB/s +test bench::one_pass_short_not ... bench: 2,588 ns/iter (+/- 8) = 6 MB/s +test bench::replace_all ... bench: 905 ns/iter (+/- 7) +test bench_dynamic_compile::compile_huge ... bench: 161,517 ns/iter (+/- 1,287) +test bench_dynamic_compile::compile_huge_bytes ... bench: 18,395,715 ns/iter (+/- 98,986) +test bench_dynamic_compile::compile_simple ... bench: 6,623 ns/iter (+/- 296) +test bench_dynamic_compile::compile_simple_bytes ... bench: 7,047 ns/iter (+/- 232) +test bench_dynamic_compile::compile_small ... bench: 8,948 ns/iter (+/- 526) +test bench_dynamic_compile::compile_small_bytes ... bench: 186,796 ns/iter (+/- 817) +test bench_dynamic_parse::parse_huge ... bench: 1,238 ns/iter (+/- 6) +test bench_dynamic_parse::parse_simple ... bench: 1,977 ns/iter (+/- 12) +test bench_dynamic_parse::parse_small ... bench: 2,502 ns/iter (+/- 18) +test bench_sherlock::before_holmes ... bench: 45,045,123 ns/iter (+/- 261,188) = 13 MB/s +test bench_sherlock::everything_greedy ... bench: 38,685,654 ns/iter (+/- 107,136) = 15 MB/s +test bench_sherlock::everything_greedy_nl ... bench: 36,407,787 ns/iter (+/- 160,253) = 16 MB/s +test bench_sherlock::holmes_cochar_watson ... bench: 1,417,371 ns/iter (+/- 6,533) = 419 MB/s +test bench_sherlock::holmes_coword_watson ... bench: 139,298,695 ns/iter (+/- 154,012) = 4 MB/s +test bench_sherlock::line_boundary_sherlock_holmes ... bench: 32,734,005 ns/iter (+/- 98,729) = 18 MB/s +test bench_sherlock::name_alt1 ... bench: 153,016 ns/iter (+/- 739) = 3888 MB/s +test bench_sherlock::name_alt2 ... bench: 534,038 ns/iter (+/- 1,909) = 1114 MB/s +test bench_sherlock::name_alt3 ... bench: 2,220,778 ns/iter (+/- 6,374) = 267 MB/s +test bench_sherlock::name_alt3_nocase ... bench: 4,744,134 ns/iter (+/- 11,703) = 125 MB/s +test bench_sherlock::name_alt4 ... bench: 569,971 ns/iter (+/- 2,256) = 1043 MB/s +test bench_sherlock::name_alt4_nocase ... bench: 2,324,966 ns/iter (+/- 3,082) = 255 MB/s +test bench_sherlock::name_holmes ... bench: 268,146 ns/iter (+/- 1,238) = 2218 MB/s +test bench_sherlock::name_holmes_nocase ... bench: 1,409,583 ns/iter (+/- 2,808) = 422 MB/s +test bench_sherlock::name_sherlock ... bench: 95,280 ns/iter (+/- 316) = 6244 MB/s +test bench_sherlock::name_sherlock_holmes ... bench: 116,097 ns/iter (+/- 461) = 5124 MB/s +test bench_sherlock::name_sherlock_holmes_nocase ... bench: 1,691,210 ns/iter (+/- 3,712) = 351 MB/s +test bench_sherlock::name_sherlock_nocase ... bench: 1,651,722 ns/iter (+/- 7,070) = 360 MB/s +test bench_sherlock::name_whitespace ... bench: 130,960 ns/iter (+/- 923) = 4542 MB/s +test bench_sherlock::no_match_common ... bench: 568,008 ns/iter (+/- 1,723) = 1047 MB/s +test bench_sherlock::no_match_uncommon ... bench: 23,669 ns/iter (+/- 84) = 25135 MB/s +test bench_sherlock::quotes ... bench: 11,055,260 ns/iter (+/- 24,883) = 53 MB/s +test bench_sherlock::the_lower ... bench: 2,934,498 ns/iter (+/- 4,553) = 202 MB/s +test bench_sherlock::the_nocase ... bench: 4,268,193 ns/iter (+/- 8,164) = 139 MB/s +test bench_sherlock::the_upper ... bench: 272,832 ns/iter (+/- 1,436) = 2180 MB/s +test bench_sherlock::the_whitespace ... bench: 5,409,934 ns/iter (+/- 7,678) = 109 MB/s +test bench_sherlock::word_ending_n ... bench: 55,252,656 ns/iter (+/- 68,442) = 10 MB/s + +test result: ok. 0 passed; 0 failed; 0 ignored; 67 measured + diff --git a/benches/log/01-lazy-dfa/pcre b/benches/log/01-lazy-dfa/pcre new file mode 100644 index 0000000000..22a66e6a8b --- /dev/null +++ b/benches/log/01-lazy-dfa/pcre @@ -0,0 +1,60 @@ + Compiling regex v0.1.48 (file:///home/andrew/data/projects/rust/regex) + Running target/release/pcre-781840b9a3e9c199 + +running 53 tests +test anchored_literal_long_match ... bench: 90 ns/iter (+/- 7) = 4333 MB/s +test anchored_literal_long_non_match ... bench: 60 ns/iter (+/- 2) = 6500 MB/s +test anchored_literal_short_match ... bench: 87 ns/iter (+/- 6) = 298 MB/s +test anchored_literal_short_non_match ... bench: 58 ns/iter (+/- 4) = 448 MB/s +test easy0_1K ... bench: 258 ns/iter (+/- 14) = 3968 MB/s +test easy0_1MB ... bench: 226,139 ns/iter (+/- 1,637) = 4636 MB/s +test easy0_32 ... bench: 60 ns/iter (+/- 7) = 533 MB/s +test easy0_32K ... bench: 7,028 ns/iter (+/- 120) = 4662 MB/s +test easy1_1K ... bench: 794 ns/iter (+/- 20) = 1289 MB/s +test easy1_1MB ... bench: 751,438 ns/iter (+/- 11,372) = 1395 MB/s +test easy1_32 ... bench: 71 ns/iter (+/- 3) = 450 MB/s +test easy1_32K ... bench: 23,042 ns/iter (+/- 1,453) = 1422 MB/s +test hard_1K ... bench: 30,841 ns/iter (+/- 1,287) = 33 MB/s +test hard_1MB ... bench: 35,239,100 ns/iter (+/- 632,179) = 29 MB/s +test hard_32 ... bench: 86 ns/iter (+/- 11) = 372 MB/s +test hard_32K ... bench: 993,011 ns/iter (+/- 63,648) = 32 MB/s +test literal ... bench: 130 ns/iter (+/- 11) = 392 MB/s +test match_class ... bench: 183 ns/iter (+/- 33) = 442 MB/s +test match_class_in_range ... bench: 175 ns/iter (+/- 18) = 462 MB/s +test match_class_unicode ... bench: 513 ns/iter (+/- 8) = 313 MB/s +test medium_1K ... bench: 278 ns/iter (+/- 6) = 3683 MB/s +test medium_1MB ... bench: 240,699 ns/iter (+/- 17,344) = 4356 MB/s +test medium_32 ... bench: 61 ns/iter (+/- 13) = 524 MB/s +test medium_32K ... bench: 7,369 ns/iter (+/- 105) = 4446 MB/s +test not_literal ... bench: 274 ns/iter (+/- 17) = 186 MB/s +test one_pass_long_prefix ... bench: 87 ns/iter (+/- 19) = 298 MB/s +test one_pass_long_prefix_not ... bench: 86 ns/iter (+/- 13) = 302 MB/s +test one_pass_short ... bench: 117 ns/iter (+/- 44) = 145 MB/s +test one_pass_short_not ... bench: 122 ns/iter (+/- 6) = 139 MB/s +test sherlock::before_holmes ... bench: 14,450,308 ns/iter (+/- 617,786) = 41 MB/s +test sherlock::holmes_cochar_watson ... bench: 546,919 ns/iter (+/- 4,880) = 1087 MB/s +test sherlock::line_boundary_sherlock_holmes ... bench: 194,524 ns/iter (+/- 6,230) = 3058 MB/s +test sherlock::name_alt1 ... bench: 457,899 ns/iter (+/- 7,781) = 1299 MB/s +test sherlock::name_alt2 ... bench: 496,659 ns/iter (+/- 6,529) = 1197 MB/s +test sherlock::name_alt3 ... bench: 983,620 ns/iter (+/- 45,359) = 604 MB/s +test sherlock::name_alt3_nocase ... bench: 3,500,367 ns/iter (+/- 79,807) = 169 MB/s +test sherlock::name_alt4 ... bench: 972,128 ns/iter (+/- 22,195) = 611 MB/s +test sherlock::name_alt4_nocase ... bench: 1,877,017 ns/iter (+/- 39,079) = 316 MB/s +test sherlock::name_holmes ... bench: 398,258 ns/iter (+/- 4,338) = 1493 MB/s +test sherlock::name_holmes_nocase ... bench: 492,292 ns/iter (+/- 4,667) = 1208 MB/s +test sherlock::name_sherlock ... bench: 268,891 ns/iter (+/- 18,063) = 2212 MB/s +test sherlock::name_sherlock_holmes ... bench: 197,067 ns/iter (+/- 8,027) = 3018 MB/s +test sherlock::name_sherlock_holmes_nocase ... bench: 1,112,501 ns/iter (+/- 44,457) = 534 MB/s +test sherlock::name_sherlock_nocase ... bench: 1,332,423 ns/iter (+/- 39,227) = 446 MB/s +test sherlock::name_whitespace ... bench: 267,257 ns/iter (+/- 964) = 2226 MB/s +test sherlock::no_match_common ... bench: 595,211 ns/iter (+/- 3,739) = 999 MB/s +test sherlock::no_match_uncommon ... bench: 584,057 ns/iter (+/- 6,825) = 1018 MB/s +test sherlock::quotes ... bench: 1,208,235 ns/iter (+/- 37,629) = 492 MB/s +test sherlock::the_lower ... bench: 1,210,851 ns/iter (+/- 35,900) = 491 MB/s +test sherlock::the_nocase ... bench: 1,286,611 ns/iter (+/- 35,689) = 462 MB/s +test sherlock::the_upper ... bench: 776,113 ns/iter (+/- 6,236) = 766 MB/s +test sherlock::the_whitespace ... bench: 1,368,468 ns/iter (+/- 135,282) = 434 MB/s +test sherlock::word_ending_n ... bench: 12,018,618 ns/iter (+/- 266,497) = 49 MB/s + +test result: ok. 0 passed; 0 failed; 0 ignored; 53 measured + diff --git a/benches/log/old/01-before b/benches/log/old/01-before new file mode 100644 index 0000000000..74890a34fe --- /dev/null +++ b/benches/log/old/01-before @@ -0,0 +1,28 @@ +test bench::anchored_literal_long_match ... bench: 520 ns/iter (+/- 1) +test bench::anchored_literal_long_non_match ... bench: 236 ns/iter (+/- 2) +test bench::anchored_literal_short_match ... bench: 519 ns/iter (+/- 2) +test bench::anchored_literal_short_non_match ... bench: 238 ns/iter (+/- 2) +test bench::easy0_1K ... bench: 7742 ns/iter (+/- 97) = 132 MB/s +test bench::easy0_32 ... bench: 4989 ns/iter (+/- 20) = 6 MB/s +test bench::easy0_32K ... bench: 96347 ns/iter (+/- 997) = 340 MB/s +test bench::easy1_1K ... bench: 9805 ns/iter (+/- 1846) = 104 MB/s +test bench::easy1_32 ... bench: 4930 ns/iter (+/- 202) = 6 MB/s +test bench::easy1_32K ... bench: 163332 ns/iter (+/- 9207) = 200 MB/s +test bench::hard_1K ... bench: 97455 ns/iter (+/- 1089) = 10 MB/s +test bench::hard_32 ... bench: 8256 ns/iter (+/- 148) = 3 MB/s +test bench::hard_32K ... bench: 2948095 ns/iter (+/- 11988) = 11 MB/s +test bench::literal ... bench: 371 ns/iter (+/- 5) +test bench::match_class ... bench: 2168 ns/iter (+/- 12) +test bench::match_class_in_range ... bench: 2379 ns/iter (+/- 13) +test bench::medium_1K ... bench: 37073 ns/iter (+/- 1100) = 27 MB/s +test bench::medium_32 ... bench: 6183 ns/iter (+/- 218) = 5 MB/s +test bench::medium_32K ... bench: 1032000 ns/iter (+/- 8278) = 31 MB/s +test bench::no_exponential ... bench: 727975 ns/iter (+/- 2970) +test bench::not_literal ... bench: 4670 ns/iter (+/- 29) +test bench::one_pass_long_prefix ... bench: 1562 ns/iter (+/- 24) +test bench::one_pass_long_prefix_not ... bench: 1539 ns/iter (+/- 40) +test bench::one_pass_short_a ... bench: 2688 ns/iter (+/- 21) +test bench::one_pass_short_a_not ... bench: 4197 ns/iter (+/- 36) +test bench::one_pass_short_b ... bench: 2198 ns/iter (+/- 22) +test bench::one_pass_short_b_not ... bench: 3761 ns/iter (+/- 41) +test bench::replace_all ... bench: 2874 ns/iter (+/- 25) diff --git a/benches/log/old/02-new-syntax-crate b/benches/log/old/02-new-syntax-crate new file mode 100644 index 0000000000..267808ffb7 --- /dev/null +++ b/benches/log/old/02-new-syntax-crate @@ -0,0 +1,28 @@ +test bench::anchored_literal_long_match ... bench: 545 ns/iter (+/- 12) +test bench::anchored_literal_long_non_match ... bench: 251 ns/iter (+/- 11) +test bench::anchored_literal_short_match ... bench: 521 ns/iter (+/- 31) +test bench::anchored_literal_short_non_match ... bench: 231 ns/iter (+/- 0) +test bench::easy0_1K ... bench: 7465 ns/iter (+/- 102) = 137 MB/s +test bench::easy0_32 ... bench: 4995 ns/iter (+/- 27) = 6 MB/s +test bench::easy0_32K ... bench: 86985 ns/iter (+/- 755) = 376 MB/s +test bench::easy1_1K ... bench: 9493 ns/iter (+/- 1727) = 107 MB/s +test bench::easy1_32 ... bench: 4955 ns/iter (+/- 324) = 6 MB/s +test bench::easy1_32K ... bench: 155288 ns/iter (+/- 13016) = 210 MB/s +test bench::hard_1K ... bench: 95925 ns/iter (+/- 1674) = 10 MB/s +test bench::hard_32 ... bench: 8264 ns/iter (+/- 151) = 3 MB/s +test bench::hard_32K ... bench: 2886440 ns/iter (+/- 25807) = 11 MB/s +test bench::literal ... bench: 365 ns/iter (+/- 12) +test bench::match_class ... bench: 2313 ns/iter (+/- 8) +test bench::match_class_in_range ... bench: 2596 ns/iter (+/- 8) +test bench::medium_1K ... bench: 38136 ns/iter (+/- 941) = 26 MB/s +test bench::medium_32 ... bench: 6178 ns/iter (+/- 147) = 5 MB/s +test bench::medium_32K ... bench: 1065698 ns/iter (+/- 6815) = 30 MB/s +test bench::no_exponential ... bench: 682461 ns/iter (+/- 2860) +test bench::not_literal ... bench: 4525 ns/iter (+/- 67) +test bench::one_pass_long_prefix ... bench: 1459 ns/iter (+/- 13) +test bench::one_pass_long_prefix_not ... bench: 1463 ns/iter (+/- 8) +test bench::one_pass_short_a ... bench: 2615 ns/iter (+/- 10) +test bench::one_pass_short_a_not ... bench: 4066 ns/iter (+/- 48) +test bench::one_pass_short_b ... bench: 2064 ns/iter (+/- 10) +test bench::one_pass_short_b_not ... bench: 3502 ns/iter (+/- 24) +test bench::replace_all ... bench: 2949 ns/iter (+/- 15) diff --git a/benches/log/old/03-new-syntax-crate b/benches/log/old/03-new-syntax-crate new file mode 100644 index 0000000000..a50005d85e --- /dev/null +++ b/benches/log/old/03-new-syntax-crate @@ -0,0 +1,28 @@ +test bench::anchored_literal_long_match ... bench: 373 ns/iter (+/- 5) +test bench::anchored_literal_long_non_match ... bench: 204 ns/iter (+/- 3) +test bench::anchored_literal_short_match ... bench: 376 ns/iter (+/- 5) +test bench::anchored_literal_short_non_match ... bench: 206 ns/iter (+/- 3) +test bench::easy0_1K ... bench: 9136 ns/iter (+/- 177) = 112 MB/s +test bench::easy0_32 ... bench: 6641 ns/iter (+/- 86) = 4 MB/s +test bench::easy0_32K ... bench: 88826 ns/iter (+/- 1366) = 368 MB/s +test bench::easy1_1K ... bench: 10937 ns/iter (+/- 737) = 93 MB/s +test bench::easy1_32 ... bench: 7366 ns/iter (+/- 219) = 4 MB/s +test bench::easy1_32K ... bench: 122324 ns/iter (+/- 4628) = 267 MB/s +test bench::hard_1K ... bench: 59998 ns/iter (+/- 965) = 17 MB/s +test bench::hard_32 ... bench: 9058 ns/iter (+/- 123) = 3 MB/s +test bench::hard_32K ... bench: 1694326 ns/iter (+/- 27226) = 19 MB/s +test bench::literal ... bench: 336 ns/iter (+/- 6) +test bench::match_class ... bench: 2109 ns/iter (+/- 27) +test bench::match_class_in_range ... bench: 2274 ns/iter (+/- 32) +test bench::medium_1K ... bench: 38317 ns/iter (+/- 1075) = 26 MB/s +test bench::medium_32 ... bench: 7969 ns/iter (+/- 115) = 4 MB/s +test bench::medium_32K ... bench: 1028260 ns/iter (+/- 12905) = 31 MB/s +test bench::no_exponential ... bench: 257719 ns/iter (+/- 4939) +test bench::not_literal ... bench: 1699 ns/iter (+/- 31) +test bench::one_pass_long_prefix ... bench: 750 ns/iter (+/- 9) +test bench::one_pass_long_prefix_not ... bench: 747 ns/iter (+/- 12) +test bench::one_pass_short_a ... bench: 1844 ns/iter (+/- 22) +test bench::one_pass_short_a_not ... bench: 2395 ns/iter (+/- 21) +test bench::one_pass_short_b ... bench: 1270 ns/iter (+/- 26) +test bench::one_pass_short_b_not ... bench: 1869 ns/iter (+/- 25) +test bench::replace_all ... bench: 3124 ns/iter (+/- 53) diff --git a/benches/log/old/04-fixed-benchmark b/benches/log/old/04-fixed-benchmark new file mode 100644 index 0000000000..1956e98466 --- /dev/null +++ b/benches/log/old/04-fixed-benchmark @@ -0,0 +1,28 @@ +test bench::anchored_literal_long_match ... bench: 373 ns/iter (+/- 5) +test bench::anchored_literal_long_non_match ... bench: 202 ns/iter (+/- 12) +test bench::anchored_literal_short_match ... bench: 380 ns/iter (+/- 135) +test bench::anchored_literal_short_non_match ... bench: 211 ns/iter (+/- 1) +test bench::easy0_1K ... bench: 2,723 ns/iter (+/- 101) = 376 MB/s +test bench::easy0_32 ... bench: 255 ns/iter (+/- 2) = 125 MB/s +test bench::easy0_32K ... bench: 81,845 ns/iter (+/- 598) = 400 MB/s +test bench::easy1_1K ... bench: 3,872 ns/iter (+/- 783) = 264 MB/s +test bench::easy1_32 ... bench: 287 ns/iter (+/- 143) = 111 MB/s +test bench::easy1_32K ... bench: 115,340 ns/iter (+/- 4,717) = 284 MB/s +test bench::hard_1K ... bench: 52,484 ns/iter (+/- 472) = 19 MB/s +test bench::hard_32 ... bench: 1,923 ns/iter (+/- 49) = 16 MB/s +test bench::hard_32K ... bench: 1,710,214 ns/iter (+/- 9,733) = 19 MB/s +test bench::literal ... bench: 337 ns/iter (+/- 13) +test bench::match_class ... bench: 2,141 ns/iter (+/- 7) +test bench::match_class_in_range ... bench: 2,301 ns/iter (+/- 7) +test bench::medium_1K ... bench: 31,696 ns/iter (+/- 961) = 32 MB/s +test bench::medium_32 ... bench: 1,155 ns/iter (+/- 71) = 27 MB/s +test bench::medium_32K ... bench: 1,016,101 ns/iter (+/- 12,090) = 32 MB/s +test bench::no_exponential ... bench: 262,801 ns/iter (+/- 1,332) +test bench::not_literal ... bench: 1,729 ns/iter (+/- 3) +test bench::one_pass_long_prefix ... bench: 779 ns/iter (+/- 4) +test bench::one_pass_long_prefix_not ... bench: 779 ns/iter (+/- 6) +test bench::one_pass_short_a ... bench: 1,943 ns/iter (+/- 10) +test bench::one_pass_short_a_not ... bench: 2,545 ns/iter (+/- 9) +test bench::one_pass_short_b ... bench: 1,364 ns/iter (+/- 4) +test bench::one_pass_short_b_not ... bench: 2,029 ns/iter (+/- 22) +test bench::replace_all ... bench: 3,185 ns/iter (+/- 12) diff --git a/benches/log/old/05-thread-caching b/benches/log/old/05-thread-caching new file mode 100644 index 0000000000..238f978b39 --- /dev/null +++ b/benches/log/old/05-thread-caching @@ -0,0 +1,29 @@ +test bench::anchored_literal_long_match ... bench: 287 ns/iter (+/- 11) +test bench::anchored_literal_long_non_match ... bench: 111 ns/iter (+/- 0) +test bench::anchored_literal_short_match ... bench: 286 ns/iter (+/- 4) +test bench::anchored_literal_short_non_match ... bench: 114 ns/iter (+/- 0) +test bench::easy0_1K ... bench: 2562 ns/iter (+/- 94) = 399 MB/s +test bench::easy0_32 ... bench: 95 ns/iter (+/- 1) = 336 MB/s +test bench::easy0_32K ... bench: 81755 ns/iter (+/- 576) = 400 MB/s +test bench::easy1_1K ... bench: 3586 ns/iter (+/- 917) = 285 MB/s +test bench::easy1_32 ... bench: 155 ns/iter (+/- 132) = 206 MB/s +test bench::easy1_32K ... bench: 113980 ns/iter (+/- 9331) = 287 MB/s +test bench::hard_1K ... bench: 54573 ns/iter (+/- 565) = 18 MB/s +test bench::hard_32 ... bench: 1806 ns/iter (+/- 44) = 17 MB/s +test bench::hard_32K ... bench: 1754465 ns/iter (+/- 7867) = 18 MB/s +test bench::literal ... bench: 299 ns/iter (+/- 1) +test bench::match_class ... bench: 2399 ns/iter (+/- 23) +test bench::match_class_in_range ... bench: 2142 ns/iter (+/- 8) +test bench::match_class_unicode ... bench: 2804 ns/iter (+/- 9) +test bench::medium_1K ... bench: 29536 ns/iter (+/- 537) = 34 MB/s +test bench::medium_32 ... bench: 962 ns/iter (+/- 59) = 33 MB/s +test bench::medium_32K ... bench: 946483 ns/iter (+/- 7106) = 34 MB/s +test bench::no_exponential ... bench: 274301 ns/iter (+/- 552) +test bench::not_literal ... bench: 2039 ns/iter (+/- 13) +test bench::one_pass_long_prefix ... bench: 573 ns/iter (+/- 3) +test bench::one_pass_long_prefix_not ... bench: 577 ns/iter (+/- 4) +test bench::one_pass_short_a ... bench: 1951 ns/iter (+/- 29) +test bench::one_pass_short_a_not ... bench: 2464 ns/iter (+/- 10) +test bench::one_pass_short_b ... bench: 1301 ns/iter (+/- 6) +test bench::one_pass_short_b_not ... bench: 1785 ns/iter (+/- 6) +test bench::replace_all ... bench: 2168 ns/iter (+/- 152) diff --git a/benches/log/old/06-major-dynamic b/benches/log/old/06-major-dynamic new file mode 100644 index 0000000000..123efdde31 --- /dev/null +++ b/benches/log/old/06-major-dynamic @@ -0,0 +1,33 @@ +test bench::anchored_literal_long_match ... bench: 206 ns/iter (+/- 7) +test bench::anchored_literal_long_non_match ... bench: 97 ns/iter (+/- 1) +test bench::anchored_literal_short_match ... bench: 193 ns/iter (+/- 1) +test bench::anchored_literal_short_non_match ... bench: 86 ns/iter (+/- 0) +test bench::easy0_1K ... bench: 356 ns/iter (+/- 136) = 2876 MB/s +test bench::easy0_1MB ... bench: 352,434 ns/iter (+/- 7,874) = 2974 MB/s +test bench::easy0_32 ... bench: 72 ns/iter (+/- 21) = 444 MB/s +test bench::easy0_32K ... bench: 11,053 ns/iter (+/- 1,388) = 2964 MB/s +test bench::easy1_1K ... bench: 331 ns/iter (+/- 162) = 3093 MB/s +test bench::easy1_1MB ... bench: 353,723 ns/iter (+/- 6,836) = 2964 MB/s +test bench::easy1_32 ... bench: 73 ns/iter (+/- 20) = 438 MB/s +test bench::easy1_32K ... bench: 10,297 ns/iter (+/- 1,137) = 3182 MB/s +test bench::hard_1K ... bench: 34,951 ns/iter (+/- 171) = 29 MB/s +test bench::hard_1MB ... bench: 63,323,613 ns/iter (+/- 279,582) = 15 MB/s +test bench::hard_32 ... bench: 1,131 ns/iter (+/- 13) = 28 MB/s +test bench::hard_32K ... bench: 1,099,921 ns/iter (+/- 1,338) = 29 MB/s +test bench::literal ... bench: 16 ns/iter (+/- 0) +test bench::match_class ... bench: 188 ns/iter (+/- 0) +test bench::match_class_in_range ... bench: 188 ns/iter (+/- 0) +test bench::match_class_unicode ... bench: 1,940 ns/iter (+/- 10) +test bench::medium_1K ... bench: 5,262 ns/iter (+/- 256) = 194 MB/s +test bench::medium_1MB ... bench: 5,295,539 ns/iter (+/- 9,808) = 197 MB/s +test bench::medium_32 ... bench: 217 ns/iter (+/- 19) = 147 MB/s +test bench::medium_32K ... bench: 169,169 ns/iter (+/- 1,606) = 193 MB/s +test bench::no_exponential ... bench: 293,739 ns/iter (+/- 1,632) +test bench::not_literal ... bench: 1,371 ns/iter (+/- 136) +test bench::one_pass_long_prefix ... bench: 337 ns/iter (+/- 6) +test bench::one_pass_long_prefix_not ... bench: 341 ns/iter (+/- 6) +test bench::one_pass_short_a ... bench: 1,399 ns/iter (+/- 16) +test bench::one_pass_short_a_not ... bench: 1,229 ns/iter (+/- 13) +test bench::one_pass_short_b ... bench: 844 ns/iter (+/- 24) +test bench::one_pass_short_b_not ... bench: 849 ns/iter (+/- 45) +test bench::replace_all ... bench: 579 ns/iter (+/- 3) diff --git a/benches/log/old/06-major-macro b/benches/log/old/06-major-macro new file mode 100644 index 0000000000..199561dfef --- /dev/null +++ b/benches/log/old/06-major-macro @@ -0,0 +1,33 @@ +test bench::anchored_literal_long_match ... bench: 225 ns/iter (+/- 22) +test bench::anchored_literal_long_non_match ... bench: 62 ns/iter (+/- 1) +test bench::anchored_literal_short_match ... bench: 225 ns/iter (+/- 1) +test bench::anchored_literal_short_non_match ... bench: 60 ns/iter (+/- 1) +test bench::easy0_1K ... bench: 29,984 ns/iter (+/- 190) = 34 MB/s +test bench::easy0_1MB ... bench: 30,641,690 ns/iter (+/- 110,535) = 33 MB/s +test bench::easy0_32 ... bench: 981 ns/iter (+/- 12) = 32 MB/s +test bench::easy0_32K ... bench: 957,358 ns/iter (+/- 2,633) = 34 MB/s +test bench::easy1_1K ... bench: 29,636 ns/iter (+/- 150) = 34 MB/s +test bench::easy1_1MB ... bench: 30,295,321 ns/iter (+/- 98,181) = 34 MB/s +test bench::easy1_32 ... bench: 971 ns/iter (+/- 30) = 32 MB/s +test bench::easy1_32K ... bench: 947,307 ns/iter (+/- 4,258) = 34 MB/s +test bench::hard_1K ... bench: 54,856 ns/iter (+/- 209) = 18 MB/s +test bench::hard_1MB ... bench: 56,126,571 ns/iter (+/- 224,163) = 17 MB/s +test bench::hard_32 ... bench: 1,776 ns/iter (+/- 23) = 18 MB/s +test bench::hard_32K ... bench: 1,753,833 ns/iter (+/- 54,427) = 18 MB/s +test bench::literal ... bench: 1,516 ns/iter (+/- 6) +test bench::match_class ... bench: 2,429 ns/iter (+/- 11) +test bench::match_class_in_range ... bench: 2,398 ns/iter (+/- 4) +test bench::match_class_unicode ... bench: 12,915 ns/iter (+/- 29) +test bench::medium_1K ... bench: 31,914 ns/iter (+/- 276) = 32 MB/s +test bench::medium_1MB ... bench: 32,617,173 ns/iter (+/- 68,114) = 31 MB/s +test bench::medium_32 ... bench: 1,046 ns/iter (+/- 42) = 30 MB/s +test bench::medium_32K ... bench: 1,019,516 ns/iter (+/- 3,788) = 32 MB/s +test bench::no_exponential ... bench: 303,239 ns/iter (+/- 518) +test bench::not_literal ... bench: 1,756 ns/iter (+/- 115) +test bench::one_pass_long_prefix ... bench: 834 ns/iter (+/- 7) +test bench::one_pass_long_prefix_not ... bench: 858 ns/iter (+/- 15) +test bench::one_pass_short_a ... bench: 1,597 ns/iter (+/- 9) +test bench::one_pass_short_a_not ... bench: 1,950 ns/iter (+/- 21) +test bench::one_pass_short_b ... bench: 1,077 ns/iter (+/- 5) +test bench::one_pass_short_b_not ... bench: 1,596 ns/iter (+/- 9) +test bench::replace_all ... bench: 1,288 ns/iter (+/- 13) diff --git a/benches/log/old/07-prefix-improvements b/benches/log/old/07-prefix-improvements new file mode 100644 index 0000000000..55477fdcef --- /dev/null +++ b/benches/log/old/07-prefix-improvements @@ -0,0 +1,33 @@ +test bench::anchored_literal_long_match ... bench: 197 ns/iter (+/- 9) +test bench::anchored_literal_long_non_match ... bench: 95 ns/iter (+/- 1) +test bench::anchored_literal_short_match ... bench: 193 ns/iter (+/- 2) +test bench::anchored_literal_short_non_match ... bench: 85 ns/iter (+/- 2) +test bench::easy0_1K ... bench: 304 ns/iter (+/- 119) = 3368 MB/s +test bench::easy0_1MB ... bench: 281,912 ns/iter (+/- 5,274) = 3719 MB/s +test bench::easy0_32 ... bench: 74 ns/iter (+/- 16) = 432 MB/s +test bench::easy0_32K ... bench: 8,909 ns/iter (+/- 667) = 3678 MB/s +test bench::easy1_1K ... bench: 300 ns/iter (+/- 111) = 3413 MB/s +test bench::easy1_1MB ... bench: 282,250 ns/iter (+/- 5,556) = 3714 MB/s +test bench::easy1_32 ... bench: 98 ns/iter (+/- 17) = 326 MB/s +test bench::easy1_32K ... bench: 8,105 ns/iter (+/- 593) = 4042 MB/s +test bench::hard_1K ... bench: 34,562 ns/iter (+/- 211) = 29 MB/s +test bench::hard_1MB ... bench: 64,510,947 ns/iter (+/- 308,627) = 15 MB/s +test bench::hard_32 ... bench: 1,139 ns/iter (+/- 26) = 28 MB/s +test bench::hard_32K ... bench: 1,102,562 ns/iter (+/- 1,850) = 29 MB/s +test bench::literal ... bench: 15 ns/iter (+/- 0) +test bench::match_class ... bench: 105 ns/iter (+/- 1) +test bench::match_class_in_range ... bench: 105 ns/iter (+/- 1) +test bench::match_class_unicode ... bench: 2,270 ns/iter (+/- 185) +test bench::medium_1K ... bench: 2,262 ns/iter (+/- 73) = 452 MB/s +test bench::medium_1MB ... bench: 2,185,098 ns/iter (+/- 3,007) = 479 MB/s +test bench::medium_32 ... bench: 139 ns/iter (+/- 1) = 230 MB/s +test bench::medium_32K ... bench: 72,320 ns/iter (+/- 193) = 453 MB/s +test bench::no_exponential ... bench: 300,699 ns/iter (+/- 494) +test bench::not_literal ... bench: 1,462 ns/iter (+/- 89) +test bench::one_pass_long_prefix ... bench: 283 ns/iter (+/- 1) +test bench::one_pass_long_prefix_not ... bench: 287 ns/iter (+/- 0) +test bench::one_pass_short_a ... bench: 1,131 ns/iter (+/- 11) +test bench::one_pass_short_a_not ... bench: 1,259 ns/iter (+/- 12) +test bench::one_pass_short_b ... bench: 883 ns/iter (+/- 15) +test bench::one_pass_short_b_not ... bench: 799 ns/iter (+/- 28) +test bench::replace_all ... bench: 170 ns/iter (+/- 1) diff --git a/benches/log/old/08-case-fixes b/benches/log/old/08-case-fixes new file mode 100644 index 0000000000..7609f6c940 --- /dev/null +++ b/benches/log/old/08-case-fixes @@ -0,0 +1,33 @@ +test bench::anchored_literal_long_match ... bench: 192 ns/iter (+/- 11) +test bench::anchored_literal_long_non_match ... bench: 92 ns/iter (+/- 4) +test bench::anchored_literal_short_match ... bench: 182 ns/iter (+/- 6) +test bench::anchored_literal_short_non_match ... bench: 82 ns/iter (+/- 1) +test bench::easy0_1K ... bench: 277 ns/iter (+/- 79) = 3696 MB/s +test bench::easy0_1MB ... bench: 230,829 ns/iter (+/- 5,712) = 4542 MB/s +test bench::easy0_32 ... bench: 70 ns/iter (+/- 4) = 457 MB/s +test bench::easy0_32K ... bench: 8,444 ns/iter (+/- 492) = 3880 MB/s +test bench::easy1_1K ... bench: 272 ns/iter (+/- 98) = 3764 MB/s +test bench::easy1_1MB ... bench: 273,867 ns/iter (+/- 6,351) = 3828 MB/s +test bench::easy1_32 ... bench: 72 ns/iter (+/- 15) = 444 MB/s +test bench::easy1_32K ... bench: 8,109 ns/iter (+/- 540) = 4040 MB/s +test bench::hard_1K ... bench: 31,043 ns/iter (+/- 1,237) = 32 MB/s +test bench::hard_1MB ... bench: 60,077,413 ns/iter (+/- 129,611) = 16 MB/s +test bench::hard_32 ... bench: 1,036 ns/iter (+/- 20) = 30 MB/s +test bench::hard_32K ... bench: 996,238 ns/iter (+/- 3,181) = 32 MB/s +test bench::literal ... bench: 15 ns/iter (+/- 0) +test bench::match_class ... bench: 75 ns/iter (+/- 7) +test bench::match_class_in_range ... bench: 77 ns/iter (+/- 7) +test bench::match_class_unicode ... bench: 2,057 ns/iter (+/- 102) +test bench::medium_1K ... bench: 2,252 ns/iter (+/- 63) = 454 MB/s +test bench::medium_1MB ... bench: 2,186,091 ns/iter (+/- 7,496) = 479 MB/s +test bench::medium_32 ... bench: 132 ns/iter (+/- 2) = 242 MB/s +test bench::medium_32K ... bench: 72,394 ns/iter (+/- 342) = 452 MB/s +test bench::no_exponential ... bench: 286,662 ns/iter (+/- 1,150) +test bench::not_literal ... bench: 1,130 ns/iter (+/- 10) +test bench::one_pass_long_prefix ... bench: 271 ns/iter (+/- 0) +test bench::one_pass_long_prefix_not ... bench: 276 ns/iter (+/- 3) +test bench::one_pass_short_a ... bench: 1,147 ns/iter (+/- 10) +test bench::one_pass_short_a_not ... bench: 901 ns/iter (+/- 8) +test bench::one_pass_short_b ... bench: 887 ns/iter (+/- 7) +test bench::one_pass_short_b_not ... bench: 777 ns/iter (+/- 6) +test bench::replace_all ... bench: 154 ns/iter (+/- 0) diff --git a/benches/log/old/09-before-compiler-rewrite b/benches/log/old/09-before-compiler-rewrite new file mode 100644 index 0000000000..fe67d096f9 --- /dev/null +++ b/benches/log/old/09-before-compiler-rewrite @@ -0,0 +1,33 @@ +test bench::anchored_literal_long_match ... bench: 156 ns/iter (+/- 5) +test bench::anchored_literal_long_non_match ... bench: 85 ns/iter (+/- 7) +test bench::anchored_literal_short_match ... bench: 145 ns/iter (+/- 3) +test bench::anchored_literal_short_non_match ... bench: 76 ns/iter (+/- 2) +test bench::easy0_1K ... bench: 269 ns/iter (+/- 63) = 3806 MB/s +test bench::easy0_1MB ... bench: 232,461 ns/iter (+/- 13,022) = 4509 MB/s +test bench::easy0_32 ... bench: 63 ns/iter (+/- 6) = 507 MB/s +test bench::easy0_32K ... bench: 8,358 ns/iter (+/- 430) = 3920 MB/s +test bench::easy1_1K ... bench: 274 ns/iter (+/- 101) = 3737 MB/s +test bench::easy1_1MB ... bench: 278,949 ns/iter (+/- 11,324) = 3758 MB/s +test bench::easy1_32 ... bench: 63 ns/iter (+/- 15) = 507 MB/s +test bench::easy1_32K ... bench: 7,731 ns/iter (+/- 488) = 4238 MB/s +test bench::hard_1K ... bench: 44,685 ns/iter (+/- 661) = 22 MB/s +test bench::hard_1MB ... bench: 60,108,237 ns/iter (+/- 814,810) = 16 MB/s +test bench::hard_32 ... bench: 1,412 ns/iter (+/- 38) = 22 MB/s +test bench::hard_32K ... bench: 1,363,335 ns/iter (+/- 21,316) = 24 MB/s +test bench::literal ... bench: 14 ns/iter (+/- 0) +test bench::match_class ... bench: 81 ns/iter (+/- 0) +test bench::match_class_in_range ... bench: 81 ns/iter (+/- 2) +test bench::match_class_unicode ... bench: 2,978 ns/iter (+/- 64) +test bench::medium_1K ... bench: 2,239 ns/iter (+/- 68) = 457 MB/s +test bench::medium_1MB ... bench: 2,215,729 ns/iter (+/- 20,897) = 472 MB/s +test bench::medium_32 ... bench: 124 ns/iter (+/- 2) = 258 MB/s +test bench::medium_32K ... bench: 72,486 ns/iter (+/- 1,027) = 452 MB/s +test bench::no_exponential ... bench: 282,992 ns/iter (+/- 8,102) +test bench::not_literal ... bench: 1,526 ns/iter (+/- 32) +test bench::one_pass_long_prefix ... bench: 307 ns/iter (+/- 7) +test bench::one_pass_long_prefix_not ... bench: 311 ns/iter (+/- 8) +test bench::one_pass_short_a ... bench: 623 ns/iter (+/- 12) +test bench::one_pass_short_a_not ... bench: 920 ns/iter (+/- 19) +test bench::one_pass_short_b ... bench: 554 ns/iter (+/- 13) +test bench::one_pass_short_b_not ... bench: 740 ns/iter (+/- 12) +test bench::replace_all ... bench: 155 ns/iter (+/- 5) diff --git a/benches/log/old/10-compiler-rewrite b/benches/log/old/10-compiler-rewrite new file mode 100644 index 0000000000..e25a602d2c --- /dev/null +++ b/benches/log/old/10-compiler-rewrite @@ -0,0 +1,33 @@ +test bench::anchored_literal_long_match ... bench: 145 ns/iter (+/- 1) +test bench::anchored_literal_long_non_match ... bench: 92 ns/iter (+/- 2) +test bench::anchored_literal_short_match ... bench: 129 ns/iter (+/- 3) +test bench::anchored_literal_short_non_match ... bench: 72 ns/iter (+/- 1) +test bench::easy0_1K ... bench: 268 ns/iter (+/- 88) = 3820 MB/s +test bench::easy0_1MB ... bench: 234,067 ns/iter (+/- 4,663) = 4479 MB/s +test bench::easy0_32 ... bench: 64 ns/iter (+/- 4) = 500 MB/s +test bench::easy0_32K ... bench: 8,298 ns/iter (+/- 521) = 3948 MB/s +test bench::easy1_1K ... bench: 275 ns/iter (+/- 95) = 3723 MB/s +test bench::easy1_1MB ... bench: 280,466 ns/iter (+/- 5,938) = 3738 MB/s +test bench::easy1_32 ... bench: 64 ns/iter (+/- 16) = 500 MB/s +test bench::easy1_32K ... bench: 7,693 ns/iter (+/- 595) = 4259 MB/s +test bench::hard_1K ... bench: 27,844 ns/iter (+/- 1,012) = 36 MB/s +test bench::hard_1MB ... bench: 52,323,489 ns/iter (+/- 1,251,665) = 19 MB/s +test bench::hard_32 ... bench: 970 ns/iter (+/- 92) = 32 MB/s +test bench::hard_32K ... bench: 896,945 ns/iter (+/- 29,977) = 36 MB/s +test bench::literal ... bench: 13 ns/iter (+/- 1) +test bench::match_class ... bench: 80 ns/iter (+/- 0) +test bench::match_class_in_range ... bench: 80 ns/iter (+/- 0) +test bench::match_class_unicode ... bench: 2,150 ns/iter (+/- 18) +test bench::medium_1K ... bench: 2,241 ns/iter (+/- 55) = 456 MB/s +test bench::medium_1MB ... bench: 2,186,354 ns/iter (+/- 9,134) = 479 MB/s +test bench::medium_32 ... bench: 125 ns/iter (+/- 1) = 256 MB/s +test bench::medium_32K ... bench: 72,156 ns/iter (+/- 145) = 454 MB/s +test bench::no_exponential ... bench: 305,034 ns/iter (+/- 1,134) +test bench::not_literal ... bench: 1,169 ns/iter (+/- 105) +test bench::one_pass_long_prefix ... bench: 257 ns/iter (+/- 4) +test bench::one_pass_long_prefix_not ... bench: 276 ns/iter (+/- 4) +test bench::one_pass_short_a ... bench: 680 ns/iter (+/- 3) +test bench::one_pass_short_a_not ... bench: 804 ns/iter (+/- 48) +test bench::one_pass_short_b ... bench: 337 ns/iter (+/- 3) +test bench::one_pass_short_b_not ... bench: 339 ns/iter (+/- 5) +test bench::replace_all ... bench: 150 ns/iter (+/- 1) diff --git a/benches/log/old/11-compiler-rewrite b/benches/log/old/11-compiler-rewrite new file mode 100644 index 0000000000..3296d4376b --- /dev/null +++ b/benches/log/old/11-compiler-rewrite @@ -0,0 +1,33 @@ +test bench::anchored_literal_long_match ... bench: 171 ns/iter (+/- 20) +test bench::anchored_literal_long_non_match ... bench: 90 ns/iter (+/- 8) +test bench::anchored_literal_short_match ... bench: 180 ns/iter (+/- 33) +test bench::anchored_literal_short_non_match ... bench: 78 ns/iter (+/- 9) +test bench::easy0_1K ... bench: 272 ns/iter (+/- 82) = 3764 MB/s +test bench::easy0_1MB ... bench: 233,014 ns/iter (+/- 22,144) = 4500 MB/s +test bench::easy0_32 ... bench: 62 ns/iter (+/- 6) = 516 MB/s +test bench::easy0_32K ... bench: 8,490 ns/iter (+/- 905) = 3859 MB/s +test bench::easy1_1K ... bench: 273 ns/iter (+/- 100) = 3750 MB/s +test bench::easy1_1MB ... bench: 279,901 ns/iter (+/- 5,598) = 3746 MB/s +test bench::easy1_32 ... bench: 62 ns/iter (+/- 6) = 516 MB/s +test bench::easy1_32K ... bench: 7,713 ns/iter (+/- 566) = 4248 MB/s +test bench::hard_1K ... bench: 38,641 ns/iter (+/- 605) = 26 MB/s +test bench::hard_1MB ... bench: 56,579,116 ns/iter (+/- 1,193,231) = 18 MB/s +test bench::hard_32 ... bench: 1,252 ns/iter (+/- 24) = 25 MB/s +test bench::hard_32K ... bench: 1,247,639 ns/iter (+/- 12,774) = 26 MB/s +test bench::literal ... bench: 13 ns/iter (+/- 1) +test bench::match_class ... bench: 80 ns/iter (+/- 1) +test bench::match_class_in_range ... bench: 80 ns/iter (+/- 0) +test bench::match_class_unicode ... bench: 2,459 ns/iter (+/- 77) +test bench::medium_1K ... bench: 2,244 ns/iter (+/- 63) = 456 MB/s +test bench::medium_1MB ... bench: 2,192,052 ns/iter (+/- 21,460) = 478 MB/s +test bench::medium_32 ... bench: 122 ns/iter (+/- 3) = 262 MB/s +test bench::medium_32K ... bench: 73,167 ns/iter (+/- 15,655) = 447 MB/s +test bench::no_exponential ... bench: 289,292 ns/iter (+/- 1,488) +test bench::not_literal ... bench: 1,480 ns/iter (+/- 18) +test bench::one_pass_long_prefix ... bench: 324 ns/iter (+/- 15) +test bench::one_pass_long_prefix_not ... bench: 337 ns/iter (+/- 5) +test bench::one_pass_short_a ... bench: 1,161 ns/iter (+/- 10) +test bench::one_pass_short_a_not ... bench: 798 ns/iter (+/- 6) +test bench::one_pass_short_b ... bench: 456 ns/iter (+/- 6) +test bench::one_pass_short_b_not ... bench: 452 ns/iter (+/- 33) +test bench::replace_all ... bench: 148 ns/iter (+/- 0) diff --git a/benches/log/old/12-executor b/benches/log/old/12-executor new file mode 100644 index 0000000000..8ec8561b56 --- /dev/null +++ b/benches/log/old/12-executor @@ -0,0 +1,35 @@ +test bench::anchored_literal_long_match ... bench: 179 ns/iter (+/- 5) +test bench::anchored_literal_long_non_match ... bench: 90 ns/iter (+/- 1) +test bench::anchored_literal_short_match ... bench: 164 ns/iter (+/- 16) +test bench::anchored_literal_short_non_match ... bench: 79 ns/iter (+/- 1) +test bench::compile_simple ... bench: 3,708 ns/iter (+/- 225) +test bench::compile_unicode ... bench: 5,871 ns/iter (+/- 264) +test bench::easy0_1K ... bench: 263 ns/iter (+/- 92) = 3893 MB/s +test bench::easy0_1MB ... bench: 217,835 ns/iter (+/- 4,074) = 4813 MB/s +test bench::easy0_32 ... bench: 67 ns/iter (+/- 1) = 477 MB/s +test bench::easy0_32K ... bench: 8,204 ns/iter (+/- 426) = 3994 MB/s +test bench::easy1_1K ... bench: 276 ns/iter (+/- 100) = 3710 MB/s +test bench::easy1_1MB ... bench: 284,086 ns/iter (+/- 6,516) = 3691 MB/s +test bench::easy1_32 ... bench: 70 ns/iter (+/- 15) = 457 MB/s +test bench::easy1_32K ... bench: 7,844 ns/iter (+/- 556) = 4177 MB/s +test bench::hard_1K ... bench: 30,062 ns/iter (+/- 1,684) = 34 MB/s +test bench::hard_1MB ... bench: 50,839,701 ns/iter (+/- 104,343) = 20 MB/s +test bench::hard_32 ... bench: 1,009 ns/iter (+/- 48) = 31 MB/s +test bench::hard_32K ... bench: 965,341 ns/iter (+/- 45,075) = 33 MB/s +test bench::literal ... bench: 12 ns/iter (+/- 0) +test bench::match_class ... bench: 80 ns/iter (+/- 0) +test bench::match_class_in_range ... bench: 80 ns/iter (+/- 1) +test bench::match_class_unicode ... bench: 2,150 ns/iter (+/- 22) +test bench::medium_1K ... bench: 2,262 ns/iter (+/- 66) = 452 MB/s +test bench::medium_1MB ... bench: 2,193,428 ns/iter (+/- 6,147) = 478 MB/s +test bench::medium_32 ... bench: 129 ns/iter (+/- 1) = 248 MB/s +test bench::medium_32K ... bench: 72,629 ns/iter (+/- 348) = 451 MB/s +test bench::no_exponential ... bench: 289,043 ns/iter (+/- 2,478) +test bench::not_literal ... bench: 1,195 ns/iter (+/- 10) +test bench::one_pass_long_prefix ... bench: 265 ns/iter (+/- 3) +test bench::one_pass_long_prefix_not ... bench: 270 ns/iter (+/- 4) +test bench::one_pass_short_a ... bench: 730 ns/iter (+/- 4) +test bench::one_pass_short_a_not ... bench: 712 ns/iter (+/- 4) +test bench::one_pass_short_b ... bench: 445 ns/iter (+/- 49) +test bench::one_pass_short_b_not ... bench: 406 ns/iter (+/- 72) +test bench::replace_all ... bench: 136 ns/iter (+/- 2) diff --git a/benches/log/old/12-executor-bytes b/benches/log/old/12-executor-bytes new file mode 100644 index 0000000000..c036920c2b --- /dev/null +++ b/benches/log/old/12-executor-bytes @@ -0,0 +1,35 @@ +test bench::anchored_literal_long_match ... bench: 190 ns/iter (+/- 12) +test bench::anchored_literal_long_non_match ... bench: 85 ns/iter (+/- 2) +test bench::anchored_literal_short_match ... bench: 147 ns/iter (+/- 9) +test bench::anchored_literal_short_non_match ... bench: 74 ns/iter (+/- 5) +test bench::compile_simple ... bench: 4,218 ns/iter (+/- 201) +test bench::compile_unicode ... bench: 402,353 ns/iter (+/- 2,642) +test bench::easy0_1K ... bench: 253 ns/iter (+/- 79) = 4047 MB/s +test bench::easy0_1MB ... bench: 215,308 ns/iter (+/- 3,474) = 4870 MB/s +test bench::easy0_32 ... bench: 64 ns/iter (+/- 4) = 500 MB/s +test bench::easy0_32K ... bench: 8,134 ns/iter (+/- 435) = 4028 MB/s +test bench::easy1_1K ... bench: 277 ns/iter (+/- 105) = 3696 MB/s +test bench::easy1_1MB ... bench: 283,435 ns/iter (+/- 5,975) = 3699 MB/s +test bench::easy1_32 ... bench: 64 ns/iter (+/- 14) = 500 MB/s +test bench::easy1_32K ... bench: 7,832 ns/iter (+/- 575) = 4183 MB/s +test bench::hard_1K ... bench: 35,380 ns/iter (+/- 772) = 28 MB/s +test bench::hard_1MB ... bench: 46,639,535 ns/iter (+/- 456,010) = 22 MB/s +test bench::hard_32 ... bench: 1,110 ns/iter (+/- 53) = 28 MB/s +test bench::hard_32K ... bench: 1,146,751 ns/iter (+/- 17,290) = 28 MB/s +test bench::literal ... bench: 12 ns/iter (+/- 0) +test bench::match_class ... bench: 80 ns/iter (+/- 1) +test bench::match_class_in_range ... bench: 80 ns/iter (+/- 0) +test bench::match_class_unicode ... bench: 2,487,088 ns/iter (+/- 103,259) +test bench::medium_1K ... bench: 2,253 ns/iter (+/- 52) = 454 MB/s +test bench::medium_1MB ... bench: 2,193,344 ns/iter (+/- 7,582) = 478 MB/s +test bench::medium_32 ... bench: 119 ns/iter (+/- 5) = 268 MB/s +test bench::medium_32K ... bench: 72,569 ns/iter (+/- 283) = 451 MB/s +test bench::no_exponential ... bench: 292,840 ns/iter (+/- 2,823) +test bench::not_literal ... bench: 6,417 ns/iter (+/- 26) +test bench::one_pass_long_prefix ... bench: 304 ns/iter (+/- 0) +test bench::one_pass_long_prefix_not ... bench: 943 ns/iter (+/- 44) +test bench::one_pass_short_a ... bench: 688 ns/iter (+/- 11) +test bench::one_pass_short_a_not ... bench: 687 ns/iter (+/- 7) +test bench::one_pass_short_b ... bench: 589 ns/iter (+/- 6) +test bench::one_pass_short_b_not ... bench: 357 ns/iter (+/- 11) +test bench::replace_all ... bench: 131 ns/iter (+/- 1) diff --git a/benches/log/old/13-cache-byte-range-suffixes b/benches/log/old/13-cache-byte-range-suffixes new file mode 100644 index 0000000000..5a2ec09d50 --- /dev/null +++ b/benches/log/old/13-cache-byte-range-suffixes @@ -0,0 +1,35 @@ +test bench::anchored_literal_long_match ... bench: 174 ns/iter (+/- 65) +test bench::anchored_literal_long_non_match ... bench: 94 ns/iter (+/- 1) +test bench::anchored_literal_short_match ... bench: 142 ns/iter (+/- 1) +test bench::anchored_literal_short_non_match ... bench: 82 ns/iter (+/- 0) +test bench::compile_simple ... bench: 4,878 ns/iter (+/- 207) +test bench::compile_unicode ... bench: 679,701 ns/iter (+/- 10,264) +test bench::easy0_1K ... bench: 257 ns/iter (+/- 83) = 3984 MB/s +test bench::easy0_1MB ... bench: 217,698 ns/iter (+/- 3,307) = 4816 MB/s +test bench::easy0_32 ... bench: 61 ns/iter (+/- 3) = 524 MB/s +test bench::easy0_32K ... bench: 8,144 ns/iter (+/- 449) = 4023 MB/s +test bench::easy1_1K ... bench: 276 ns/iter (+/- 106) = 3710 MB/s +test bench::easy1_1MB ... bench: 285,518 ns/iter (+/- 4,933) = 3672 MB/s +test bench::easy1_32 ... bench: 61 ns/iter (+/- 12) = 524 MB/s +test bench::easy1_32K ... bench: 7,896 ns/iter (+/- 508) = 4149 MB/s +test bench::hard_1K ... bench: 35,361 ns/iter (+/- 684) = 28 MB/s +test bench::hard_1MB ... bench: 48,691,236 ns/iter (+/- 2,316,446) = 21 MB/s +test bench::hard_32 ... bench: 1,087 ns/iter (+/- 33) = 29 MB/s +test bench::hard_32K ... bench: 1,147,627 ns/iter (+/- 4,982) = 28 MB/s +test bench::literal ... bench: 12 ns/iter (+/- 0) +test bench::match_class ... bench: 80 ns/iter (+/- 0) +test bench::match_class_in_range ... bench: 80 ns/iter (+/- 0) +test bench::match_class_unicode ... bench: 2,431,592 ns/iter (+/- 89,268) +test bench::medium_1K ... bench: 2,245 ns/iter (+/- 93) = 456 MB/s +test bench::medium_1MB ... bench: 2,192,828 ns/iter (+/- 4,343) = 478 MB/s +test bench::medium_32 ... bench: 120 ns/iter (+/- 2) = 266 MB/s +test bench::medium_32K ... bench: 72,996 ns/iter (+/- 627) = 448 MB/s +test bench::no_exponential ... bench: 290,775 ns/iter (+/- 1,176) +test bench::not_literal ... bench: 5,282 ns/iter (+/- 199) +test bench::one_pass_long_prefix ... bench: 294 ns/iter (+/- 3) +test bench::one_pass_long_prefix_not ... bench: 315 ns/iter (+/- 7) +test bench::one_pass_short_a ... bench: 708 ns/iter (+/- 21) +test bench::one_pass_short_a_not ... bench: 861 ns/iter (+/- 9) +test bench::one_pass_short_b ... bench: 607 ns/iter (+/- 2) +test bench::one_pass_short_b_not ... bench: 344 ns/iter (+/- 11) +test bench::replace_all ... bench: 135 ns/iter (+/- 1) diff --git a/benches/the-adventures-of-sherlock-holmes.txt b/benches/the-adventures-of-sherlock-holmes.txt new file mode 100644 index 0000000000..c4c3130503 --- /dev/null +++ b/benches/the-adventures-of-sherlock-holmes.txt @@ -0,0 +1,13052 @@ +Project Gutenberg's The Adventures of Sherlock Holmes, by Arthur Conan Doyle + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.net + + +Title: The Adventures of Sherlock Holmes + +Author: Arthur Conan Doyle + +Posting Date: April 18, 2011 [EBook #1661] +First Posted: November 29, 2002 + +Language: English + + +*** START OF THIS PROJECT GUTENBERG EBOOK THE ADVENTURES OF SHERLOCK HOLMES *** + + + + +Produced by an anonymous Project Gutenberg volunteer and Jose Menendez + + + + + + + + + +THE ADVENTURES OF SHERLOCK HOLMES + +by + +SIR ARTHUR CONAN DOYLE + + + + I. A Scandal in Bohemia + II. The Red-headed League + III. A Case of Identity + IV. The Boscombe Valley Mystery + V. The Five Orange Pips + VI. The Man with the Twisted Lip + VII. The Adventure of the Blue Carbuncle +VIII. The Adventure of the Speckled Band + IX. The Adventure of the Engineer's Thumb + X. The Adventure of the Noble Bachelor + XI. The Adventure of the Beryl Coronet + XII. The Adventure of the Copper Beeches + + + + +ADVENTURE I. A SCANDAL IN BOHEMIA + +I. + +To Sherlock Holmes she is always THE woman. I have seldom heard +him mention her under any other name. In his eyes she eclipses +and predominates the whole of her sex. It was not that he felt +any emotion akin to love for Irene Adler. All emotions, and that +one particularly, were abhorrent to his cold, precise but +admirably balanced mind. He was, I take it, the most perfect +reasoning and observing machine that the world has seen, but as a +lover he would have placed himself in a false position. He never +spoke of the softer passions, save with a gibe and a sneer. They +were admirable things for the observer--excellent for drawing the +veil from men's motives and actions. But for the trained reasoner +to admit such intrusions into his own delicate and finely +adjusted temperament was to introduce a distracting factor which +might throw a doubt upon all his mental results. Grit in a +sensitive instrument, or a crack in one of his own high-power +lenses, would not be more disturbing than a strong emotion in a +nature such as his. And yet there was but one woman to him, and +that woman was the late Irene Adler, of dubious and questionable +memory. + +I had seen little of Holmes lately. My marriage had drifted us +away from each other. My own complete happiness, and the +home-centred interests which rise up around the man who first +finds himself master of his own establishment, were sufficient to +absorb all my attention, while Holmes, who loathed every form of +society with his whole Bohemian soul, remained in our lodgings in +Baker Street, buried among his old books, and alternating from +week to week between cocaine and ambition, the drowsiness of the +drug, and the fierce energy of his own keen nature. He was still, +as ever, deeply attracted by the study of crime, and occupied his +immense faculties and extraordinary powers of observation in +following out those clues, and clearing up those mysteries which +had been abandoned as hopeless by the official police. From time +to time I heard some vague account of his doings: of his summons +to Odessa in the case of the Trepoff murder, of his clearing up +of the singular tragedy of the Atkinson brothers at Trincomalee, +and finally of the mission which he had accomplished so +delicately and successfully for the reigning family of Holland. +Beyond these signs of his activity, however, which I merely +shared with all the readers of the daily press, I knew little of +my former friend and companion. + +One night--it was on the twentieth of March, 1888--I was +returning from a journey to a patient (for I had now returned to +civil practice), when my way led me through Baker Street. As I +passed the well-remembered door, which must always be associated +in my mind with my wooing, and with the dark incidents of the +Study in Scarlet, I was seized with a keen desire to see Holmes +again, and to know how he was employing his extraordinary powers. +His rooms were brilliantly lit, and, even as I looked up, I saw +his tall, spare figure pass twice in a dark silhouette against +the blind. He was pacing the room swiftly, eagerly, with his head +sunk upon his chest and his hands clasped behind him. To me, who +knew his every mood and habit, his attitude and manner told their +own story. He was at work again. He had risen out of his +drug-created dreams and was hot upon the scent of some new +problem. I rang the bell and was shown up to the chamber which +had formerly been in part my own. + +His manner was not effusive. It seldom was; but he was glad, I +think, to see me. With hardly a word spoken, but with a kindly +eye, he waved me to an armchair, threw across his case of cigars, +and indicated a spirit case and a gasogene in the corner. Then he +stood before the fire and looked me over in his singular +introspective fashion. + +"Wedlock suits you," he remarked. "I think, Watson, that you have +put on seven and a half pounds since I saw you." + +"Seven!" I answered. + +"Indeed, I should have thought a little more. Just a trifle more, +I fancy, Watson. And in practice again, I observe. You did not +tell me that you intended to go into harness." + +"Then, how do you know?" + +"I see it, I deduce it. How do I know that you have been getting +yourself very wet lately, and that you have a most clumsy and +careless servant girl?" + +"My dear Holmes," said I, "this is too much. You would certainly +have been burned, had you lived a few centuries ago. It is true +that I had a country walk on Thursday and came home in a dreadful +mess, but as I have changed my clothes I can't imagine how you +deduce it. As to Mary Jane, she is incorrigible, and my wife has +given her notice, but there, again, I fail to see how you work it +out." + +He chuckled to himself and rubbed his long, nervous hands +together. + +"It is simplicity itself," said he; "my eyes tell me that on the +inside of your left shoe, just where the firelight strikes it, +the leather is scored by six almost parallel cuts. Obviously they +have been caused by someone who has very carelessly scraped round +the edges of the sole in order to remove crusted mud from it. +Hence, you see, my double deduction that you had been out in vile +weather, and that you had a particularly malignant boot-slitting +specimen of the London slavey. As to your practice, if a +gentleman walks into my rooms smelling of iodoform, with a black +mark of nitrate of silver upon his right forefinger, and a bulge +on the right side of his top-hat to show where he has secreted +his stethoscope, I must be dull, indeed, if I do not pronounce +him to be an active member of the medical profession." + +I could not help laughing at the ease with which he explained his +process of deduction. "When I hear you give your reasons," I +remarked, "the thing always appears to me to be so ridiculously +simple that I could easily do it myself, though at each +successive instance of your reasoning I am baffled until you +explain your process. And yet I believe that my eyes are as good +as yours." + +"Quite so," he answered, lighting a cigarette, and throwing +himself down into an armchair. "You see, but you do not observe. +The distinction is clear. For example, you have frequently seen +the steps which lead up from the hall to this room." + +"Frequently." + +"How often?" + +"Well, some hundreds of times." + +"Then how many are there?" + +"How many? I don't know." + +"Quite so! You have not observed. And yet you have seen. That is +just my point. Now, I know that there are seventeen steps, +because I have both seen and observed. By-the-way, since you are +interested in these little problems, and since you are good +enough to chronicle one or two of my trifling experiences, you +may be interested in this." He threw over a sheet of thick, +pink-tinted note-paper which had been lying open upon the table. +"It came by the last post," said he. "Read it aloud." + +The note was undated, and without either signature or address. + +"There will call upon you to-night, at a quarter to eight +o'clock," it said, "a gentleman who desires to consult you upon a +matter of the very deepest moment. Your recent services to one of +the royal houses of Europe have shown that you are one who may +safely be trusted with matters which are of an importance which +can hardly be exaggerated. This account of you we have from all +quarters received. Be in your chamber then at that hour, and do +not take it amiss if your visitor wear a mask." + +"This is indeed a mystery," I remarked. "What do you imagine that +it means?" + +"I have no data yet. It is a capital mistake to theorize before +one has data. Insensibly one begins to twist facts to suit +theories, instead of theories to suit facts. But the note itself. +What do you deduce from it?" + +I carefully examined the writing, and the paper upon which it was +written. + +"The man who wrote it was presumably well to do," I remarked, +endeavouring to imitate my companion's processes. "Such paper +could not be bought under half a crown a packet. It is peculiarly +strong and stiff." + +"Peculiar--that is the very word," said Holmes. "It is not an +English paper at all. Hold it up to the light." + +I did so, and saw a large "E" with a small "g," a "P," and a +large "G" with a small "t" woven into the texture of the paper. + +"What do you make of that?" asked Holmes. + +"The name of the maker, no doubt; or his monogram, rather." + +"Not at all. The 'G' with the small 't' stands for +'Gesellschaft,' which is the German for 'Company.' It is a +customary contraction like our 'Co.' 'P,' of course, stands for +'Papier.' Now for the 'Eg.' Let us glance at our Continental +Gazetteer." He took down a heavy brown volume from his shelves. +"Eglow, Eglonitz--here we are, Egria. It is in a German-speaking +country--in Bohemia, not far from Carlsbad. 'Remarkable as being +the scene of the death of Wallenstein, and for its numerous +glass-factories and paper-mills.' Ha, ha, my boy, what do you +make of that?" His eyes sparkled, and he sent up a great blue +triumphant cloud from his cigarette. + +"The paper was made in Bohemia," I said. + +"Precisely. And the man who wrote the note is a German. Do you +note the peculiar construction of the sentence--'This account of +you we have from all quarters received.' A Frenchman or Russian +could not have written that. It is the German who is so +uncourteous to his verbs. It only remains, therefore, to discover +what is wanted by this German who writes upon Bohemian paper and +prefers wearing a mask to showing his face. And here he comes, if +I am not mistaken, to resolve all our doubts." + +As he spoke there was the sharp sound of horses' hoofs and +grating wheels against the curb, followed by a sharp pull at the +bell. Holmes whistled. + +"A pair, by the sound," said he. "Yes," he continued, glancing +out of the window. "A nice little brougham and a pair of +beauties. A hundred and fifty guineas apiece. There's money in +this case, Watson, if there is nothing else." + +"I think that I had better go, Holmes." + +"Not a bit, Doctor. Stay where you are. I am lost without my +Boswell. And this promises to be interesting. It would be a pity +to miss it." + +"But your client--" + +"Never mind him. I may want your help, and so may he. Here he +comes. Sit down in that armchair, Doctor, and give us your best +attention." + +A slow and heavy step, which had been heard upon the stairs and +in the passage, paused immediately outside the door. Then there +was a loud and authoritative tap. + +"Come in!" said Holmes. + +A man entered who could hardly have been less than six feet six +inches in height, with the chest and limbs of a Hercules. His +dress was rich with a richness which would, in England, be looked +upon as akin to bad taste. Heavy bands of astrakhan were slashed +across the sleeves and fronts of his double-breasted coat, while +the deep blue cloak which was thrown over his shoulders was lined +with flame-coloured silk and secured at the neck with a brooch +which consisted of a single flaming beryl. Boots which extended +halfway up his calves, and which were trimmed at the tops with +rich brown fur, completed the impression of barbaric opulence +which was suggested by his whole appearance. He carried a +broad-brimmed hat in his hand, while he wore across the upper +part of his face, extending down past the cheekbones, a black +vizard mask, which he had apparently adjusted that very moment, +for his hand was still raised to it as he entered. From the lower +part of the face he appeared to be a man of strong character, +with a thick, hanging lip, and a long, straight chin suggestive +of resolution pushed to the length of obstinacy. + +"You had my note?" he asked with a deep harsh voice and a +strongly marked German accent. "I told you that I would call." He +looked from one to the other of us, as if uncertain which to +address. + +"Pray take a seat," said Holmes. "This is my friend and +colleague, Dr. Watson, who is occasionally good enough to help me +in my cases. Whom have I the honour to address?" + +"You may address me as the Count Von Kramm, a Bohemian nobleman. +I understand that this gentleman, your friend, is a man of honour +and discretion, whom I may trust with a matter of the most +extreme importance. If not, I should much prefer to communicate +with you alone." + +I rose to go, but Holmes caught me by the wrist and pushed me +back into my chair. "It is both, or none," said he. "You may say +before this gentleman anything which you may say to me." + +The Count shrugged his broad shoulders. "Then I must begin," said +he, "by binding you both to absolute secrecy for two years; at +the end of that time the matter will be of no importance. At +present it is not too much to say that it is of such weight it +may have an influence upon European history." + +"I promise," said Holmes. + +"And I." + +"You will excuse this mask," continued our strange visitor. "The +august person who employs me wishes his agent to be unknown to +you, and I may confess at once that the title by which I have +just called myself is not exactly my own." + +"I was aware of it," said Holmes dryly. + +"The circumstances are of great delicacy, and every precaution +has to be taken to quench what might grow to be an immense +scandal and seriously compromise one of the reigning families of +Europe. To speak plainly, the matter implicates the great House +of Ormstein, hereditary kings of Bohemia." + +"I was also aware of that," murmured Holmes, settling himself +down in his armchair and closing his eyes. + +Our visitor glanced with some apparent surprise at the languid, +lounging figure of the man who had been no doubt depicted to him +as the most incisive reasoner and most energetic agent in Europe. +Holmes slowly reopened his eyes and looked impatiently at his +gigantic client. + +"If your Majesty would condescend to state your case," he +remarked, "I should be better able to advise you." + +The man sprang from his chair and paced up and down the room in +uncontrollable agitation. Then, with a gesture of desperation, he +tore the mask from his face and hurled it upon the ground. "You +are right," he cried; "I am the King. Why should I attempt to +conceal it?" + +"Why, indeed?" murmured Holmes. "Your Majesty had not spoken +before I was aware that I was addressing Wilhelm Gottsreich +Sigismond von Ormstein, Grand Duke of Cassel-Felstein, and +hereditary King of Bohemia." + +"But you can understand," said our strange visitor, sitting down +once more and passing his hand over his high white forehead, "you +can understand that I am not accustomed to doing such business in +my own person. Yet the matter was so delicate that I could not +confide it to an agent without putting myself in his power. I +have come incognito from Prague for the purpose of consulting +you." + +"Then, pray consult," said Holmes, shutting his eyes once more. + +"The facts are briefly these: Some five years ago, during a +lengthy visit to Warsaw, I made the acquaintance of the well-known +adventuress, Irene Adler. The name is no doubt familiar to you." + +"Kindly look her up in my index, Doctor," murmured Holmes without +opening his eyes. For many years he had adopted a system of +docketing all paragraphs concerning men and things, so that it +was difficult to name a subject or a person on which he could not +at once furnish information. In this case I found her biography +sandwiched in between that of a Hebrew rabbi and that of a +staff-commander who had written a monograph upon the deep-sea +fishes. + +"Let me see!" said Holmes. "Hum! Born in New Jersey in the year +1858. Contralto--hum! La Scala, hum! Prima donna Imperial Opera +of Warsaw--yes! Retired from operatic stage--ha! Living in +London--quite so! Your Majesty, as I understand, became entangled +with this young person, wrote her some compromising letters, and +is now desirous of getting those letters back." + +"Precisely so. But how--" + +"Was there a secret marriage?" + +"None." + +"No legal papers or certificates?" + +"None." + +"Then I fail to follow your Majesty. If this young person should +produce her letters for blackmailing or other purposes, how is +she to prove their authenticity?" + +"There is the writing." + +"Pooh, pooh! Forgery." + +"My private note-paper." + +"Stolen." + +"My own seal." + +"Imitated." + +"My photograph." + +"Bought." + +"We were both in the photograph." + +"Oh, dear! That is very bad! Your Majesty has indeed committed an +indiscretion." + +"I was mad--insane." + +"You have compromised yourself seriously." + +"I was only Crown Prince then. I was young. I am but thirty now." + +"It must be recovered." + +"We have tried and failed." + +"Your Majesty must pay. It must be bought." + +"She will not sell." + +"Stolen, then." + +"Five attempts have been made. Twice burglars in my pay ransacked +her house. Once we diverted her luggage when she travelled. Twice +she has been waylaid. There has been no result." + +"No sign of it?" + +"Absolutely none." + +Holmes laughed. "It is quite a pretty little problem," said he. + +"But a very serious one to me," returned the King reproachfully. + +"Very, indeed. And what does she propose to do with the +photograph?" + +"To ruin me." + +"But how?" + +"I am about to be married." + +"So I have heard." + +"To Clotilde Lothman von Saxe-Meningen, second daughter of the +King of Scandinavia. You may know the strict principles of her +family. She is herself the very soul of delicacy. A shadow of a +doubt as to my conduct would bring the matter to an end." + +"And Irene Adler?" + +"Threatens to send them the photograph. And she will do it. I +know that she will do it. You do not know her, but she has a soul +of steel. She has the face of the most beautiful of women, and +the mind of the most resolute of men. Rather than I should marry +another woman, there are no lengths to which she would not +go--none." + +"You are sure that she has not sent it yet?" + +"I am sure." + +"And why?" + +"Because she has said that she would send it on the day when the +betrothal was publicly proclaimed. That will be next Monday." + +"Oh, then we have three days yet," said Holmes with a yawn. "That +is very fortunate, as I have one or two matters of importance to +look into just at present. Your Majesty will, of course, stay in +London for the present?" + +"Certainly. You will find me at the Langham under the name of the +Count Von Kramm." + +"Then I shall drop you a line to let you know how we progress." + +"Pray do so. I shall be all anxiety." + +"Then, as to money?" + +"You have carte blanche." + +"Absolutely?" + +"I tell you that I would give one of the provinces of my kingdom +to have that photograph." + +"And for present expenses?" + +The King took a heavy chamois leather bag from under his cloak +and laid it on the table. + +"There are three hundred pounds in gold and seven hundred in +notes," he said. + +Holmes scribbled a receipt upon a sheet of his note-book and +handed it to him. + +"And Mademoiselle's address?" he asked. + +"Is Briony Lodge, Serpentine Avenue, St. John's Wood." + +Holmes took a note of it. "One other question," said he. "Was the +photograph a cabinet?" + +"It was." + +"Then, good-night, your Majesty, and I trust that we shall soon +have some good news for you. And good-night, Watson," he added, +as the wheels of the royal brougham rolled down the street. "If +you will be good enough to call to-morrow afternoon at three +o'clock I should like to chat this little matter over with you." + + +II. + +At three o'clock precisely I was at Baker Street, but Holmes had +not yet returned. The landlady informed me that he had left the +house shortly after eight o'clock in the morning. I sat down +beside the fire, however, with the intention of awaiting him, +however long he might be. I was already deeply interested in his +inquiry, for, though it was surrounded by none of the grim and +strange features which were associated with the two crimes which +I have already recorded, still, the nature of the case and the +exalted station of his client gave it a character of its own. +Indeed, apart from the nature of the investigation which my +friend had on hand, there was something in his masterly grasp of +a situation, and his keen, incisive reasoning, which made it a +pleasure to me to study his system of work, and to follow the +quick, subtle methods by which he disentangled the most +inextricable mysteries. So accustomed was I to his invariable +success that the very possibility of his failing had ceased to +enter into my head. + +It was close upon four before the door opened, and a +drunken-looking groom, ill-kempt and side-whiskered, with an +inflamed face and disreputable clothes, walked into the room. +Accustomed as I was to my friend's amazing powers in the use of +disguises, I had to look three times before I was certain that it +was indeed he. With a nod he vanished into the bedroom, whence he +emerged in five minutes tweed-suited and respectable, as of old. +Putting his hands into his pockets, he stretched out his legs in +front of the fire and laughed heartily for some minutes. + +"Well, really!" he cried, and then he choked and laughed again +until he was obliged to lie back, limp and helpless, in the +chair. + +"What is it?" + +"It's quite too funny. I am sure you could never guess how I +employed my morning, or what I ended by doing." + +"I can't imagine. I suppose that you have been watching the +habits, and perhaps the house, of Miss Irene Adler." + +"Quite so; but the sequel was rather unusual. I will tell you, +however. I left the house a little after eight o'clock this +morning in the character of a groom out of work. There is a +wonderful sympathy and freemasonry among horsey men. Be one of +them, and you will know all that there is to know. I soon found +Briony Lodge. It is a bijou villa, with a garden at the back, but +built out in front right up to the road, two stories. Chubb lock +to the door. Large sitting-room on the right side, well +furnished, with long windows almost to the floor, and those +preposterous English window fasteners which a child could open. +Behind there was nothing remarkable, save that the passage window +could be reached from the top of the coach-house. I walked round +it and examined it closely from every point of view, but without +noting anything else of interest. + +"I then lounged down the street and found, as I expected, that +there was a mews in a lane which runs down by one wall of the +garden. I lent the ostlers a hand in rubbing down their horses, +and received in exchange twopence, a glass of half and half, two +fills of shag tobacco, and as much information as I could desire +about Miss Adler, to say nothing of half a dozen other people in +the neighbourhood in whom I was not in the least interested, but +whose biographies I was compelled to listen to." + +"And what of Irene Adler?" I asked. + +"Oh, she has turned all the men's heads down in that part. She is +the daintiest thing under a bonnet on this planet. So say the +Serpentine-mews, to a man. She lives quietly, sings at concerts, +drives out at five every day, and returns at seven sharp for +dinner. Seldom goes out at other times, except when she sings. +Has only one male visitor, but a good deal of him. He is dark, +handsome, and dashing, never calls less than once a day, and +often twice. He is a Mr. Godfrey Norton, of the Inner Temple. See +the advantages of a cabman as a confidant. They had driven him +home a dozen times from Serpentine-mews, and knew all about him. +When I had listened to all they had to tell, I began to walk up +and down near Briony Lodge once more, and to think over my plan +of campaign. + +"This Godfrey Norton was evidently an important factor in the +matter. He was a lawyer. That sounded ominous. What was the +relation between them, and what the object of his repeated +visits? Was she his client, his friend, or his mistress? If the +former, she had probably transferred the photograph to his +keeping. If the latter, it was less likely. On the issue of this +question depended whether I should continue my work at Briony +Lodge, or turn my attention to the gentleman's chambers in the +Temple. It was a delicate point, and it widened the field of my +inquiry. I fear that I bore you with these details, but I have to +let you see my little difficulties, if you are to understand the +situation." + +"I am following you closely," I answered. + +"I was still balancing the matter in my mind when a hansom cab +drove up to Briony Lodge, and a gentleman sprang out. He was a +remarkably handsome man, dark, aquiline, and moustached--evidently +the man of whom I had heard. He appeared to be in a +great hurry, shouted to the cabman to wait, and brushed past the +maid who opened the door with the air of a man who was thoroughly +at home. + +"He was in the house about half an hour, and I could catch +glimpses of him in the windows of the sitting-room, pacing up and +down, talking excitedly, and waving his arms. Of her I could see +nothing. Presently he emerged, looking even more flurried than +before. As he stepped up to the cab, he pulled a gold watch from +his pocket and looked at it earnestly, 'Drive like the devil,' he +shouted, 'first to Gross & Hankey's in Regent Street, and then to +the Church of St. Monica in the Edgeware Road. Half a guinea if +you do it in twenty minutes!' + +"Away they went, and I was just wondering whether I should not do +well to follow them when up the lane came a neat little landau, +the coachman with his coat only half-buttoned, and his tie under +his ear, while all the tags of his harness were sticking out of +the buckles. It hadn't pulled up before she shot out of the hall +door and into it. I only caught a glimpse of her at the moment, +but she was a lovely woman, with a face that a man might die for. + +"'The Church of St. Monica, John,' she cried, 'and half a +sovereign if you reach it in twenty minutes.' + +"This was quite too good to lose, Watson. I was just balancing +whether I should run for it, or whether I should perch behind her +landau when a cab came through the street. The driver looked +twice at such a shabby fare, but I jumped in before he could +object. 'The Church of St. Monica,' said I, 'and half a sovereign +if you reach it in twenty minutes.' It was twenty-five minutes to +twelve, and of course it was clear enough what was in the wind. + +"My cabby drove fast. I don't think I ever drove faster, but the +others were there before us. The cab and the landau with their +steaming horses were in front of the door when I arrived. I paid +the man and hurried into the church. There was not a soul there +save the two whom I had followed and a surpliced clergyman, who +seemed to be expostulating with them. They were all three +standing in a knot in front of the altar. I lounged up the side +aisle like any other idler who has dropped into a church. +Suddenly, to my surprise, the three at the altar faced round to +me, and Godfrey Norton came running as hard as he could towards +me. + +"'Thank God,' he cried. 'You'll do. Come! Come!' + +"'What then?' I asked. + +"'Come, man, come, only three minutes, or it won't be legal.' + +"I was half-dragged up to the altar, and before I knew where I was +I found myself mumbling responses which were whispered in my ear, +and vouching for things of which I knew nothing, and generally +assisting in the secure tying up of Irene Adler, spinster, to +Godfrey Norton, bachelor. It was all done in an instant, and +there was the gentleman thanking me on the one side and the lady +on the other, while the clergyman beamed on me in front. It was +the most preposterous position in which I ever found myself in my +life, and it was the thought of it that started me laughing just +now. It seems that there had been some informality about their +license, that the clergyman absolutely refused to marry them +without a witness of some sort, and that my lucky appearance +saved the bridegroom from having to sally out into the streets in +search of a best man. The bride gave me a sovereign, and I mean +to wear it on my watch-chain in memory of the occasion." + +"This is a very unexpected turn of affairs," said I; "and what +then?" + +"Well, I found my plans very seriously menaced. It looked as if +the pair might take an immediate departure, and so necessitate +very prompt and energetic measures on my part. At the church +door, however, they separated, he driving back to the Temple, and +she to her own house. 'I shall drive out in the park at five as +usual,' she said as she left him. I heard no more. They drove +away in different directions, and I went off to make my own +arrangements." + +"Which are?" + +"Some cold beef and a glass of beer," he answered, ringing the +bell. "I have been too busy to think of food, and I am likely to +be busier still this evening. By the way, Doctor, I shall want +your co-operation." + +"I shall be delighted." + +"You don't mind breaking the law?" + +"Not in the least." + +"Nor running a chance of arrest?" + +"Not in a good cause." + +"Oh, the cause is excellent!" + +"Then I am your man." + +"I was sure that I might rely on you." + +"But what is it you wish?" + +"When Mrs. Turner has brought in the tray I will make it clear to +you. Now," he said as he turned hungrily on the simple fare that +our landlady had provided, "I must discuss it while I eat, for I +have not much time. It is nearly five now. In two hours we must +be on the scene of action. Miss Irene, or Madame, rather, returns +from her drive at seven. We must be at Briony Lodge to meet her." + +"And what then?" + +"You must leave that to me. I have already arranged what is to +occur. There is only one point on which I must insist. You must +not interfere, come what may. You understand?" + +"I am to be neutral?" + +"To do nothing whatever. There will probably be some small +unpleasantness. Do not join in it. It will end in my being +conveyed into the house. Four or five minutes afterwards the +sitting-room window will open. You are to station yourself close +to that open window." + +"Yes." + +"You are to watch me, for I will be visible to you." + +"Yes." + +"And when I raise my hand--so--you will throw into the room what +I give you to throw, and will, at the same time, raise the cry of +fire. You quite follow me?" + +"Entirely." + +"It is nothing very formidable," he said, taking a long cigar-shaped +roll from his pocket. "It is an ordinary plumber's smoke-rocket, +fitted with a cap at either end to make it self-lighting. +Your task is confined to that. When you raise your cry of fire, +it will be taken up by quite a number of people. You may then +walk to the end of the street, and I will rejoin you in ten +minutes. I hope that I have made myself clear?" + +"I am to remain neutral, to get near the window, to watch you, +and at the signal to throw in this object, then to raise the cry +of fire, and to wait you at the corner of the street." + +"Precisely." + +"Then you may entirely rely on me." + +"That is excellent. I think, perhaps, it is almost time that I +prepare for the new role I have to play." + +He disappeared into his bedroom and returned in a few minutes in +the character of an amiable and simple-minded Nonconformist +clergyman. His broad black hat, his baggy trousers, his white +tie, his sympathetic smile, and general look of peering and +benevolent curiosity were such as Mr. John Hare alone could have +equalled. It was not merely that Holmes changed his costume. His +expression, his manner, his very soul seemed to vary with every +fresh part that he assumed. The stage lost a fine actor, even as +science lost an acute reasoner, when he became a specialist in +crime. + +It was a quarter past six when we left Baker Street, and it still +wanted ten minutes to the hour when we found ourselves in +Serpentine Avenue. It was already dusk, and the lamps were just +being lighted as we paced up and down in front of Briony Lodge, +waiting for the coming of its occupant. The house was just such +as I had pictured it from Sherlock Holmes' succinct description, +but the locality appeared to be less private than I expected. On +the contrary, for a small street in a quiet neighbourhood, it was +remarkably animated. There was a group of shabbily dressed men +smoking and laughing in a corner, a scissors-grinder with his +wheel, two guardsmen who were flirting with a nurse-girl, and +several well-dressed young men who were lounging up and down with +cigars in their mouths. + +"You see," remarked Holmes, as we paced to and fro in front of +the house, "this marriage rather simplifies matters. The +photograph becomes a double-edged weapon now. The chances are +that she would be as averse to its being seen by Mr. Godfrey +Norton, as our client is to its coming to the eyes of his +princess. Now the question is, Where are we to find the +photograph?" + +"Where, indeed?" + +"It is most unlikely that she carries it about with her. It is +cabinet size. Too large for easy concealment about a woman's +dress. She knows that the King is capable of having her waylaid +and searched. Two attempts of the sort have already been made. We +may take it, then, that she does not carry it about with her." + +"Where, then?" + +"Her banker or her lawyer. There is that double possibility. But +I am inclined to think neither. Women are naturally secretive, +and they like to do their own secreting. Why should she hand it +over to anyone else? She could trust her own guardianship, but +she could not tell what indirect or political influence might be +brought to bear upon a business man. Besides, remember that she +had resolved to use it within a few days. It must be where she +can lay her hands upon it. It must be in her own house." + +"But it has twice been burgled." + +"Pshaw! They did not know how to look." + +"But how will you look?" + +"I will not look." + +"What then?" + +"I will get her to show me." + +"But she will refuse." + +"She will not be able to. But I hear the rumble of wheels. It is +her carriage. Now carry out my orders to the letter." + +As he spoke the gleam of the side-lights of a carriage came round +the curve of the avenue. It was a smart little landau which +rattled up to the door of Briony Lodge. As it pulled up, one of +the loafing men at the corner dashed forward to open the door in +the hope of earning a copper, but was elbowed away by another +loafer, who had rushed up with the same intention. A fierce +quarrel broke out, which was increased by the two guardsmen, who +took sides with one of the loungers, and by the scissors-grinder, +who was equally hot upon the other side. A blow was struck, and +in an instant the lady, who had stepped from her carriage, was +the centre of a little knot of flushed and struggling men, who +struck savagely at each other with their fists and sticks. Holmes +dashed into the crowd to protect the lady; but just as he reached +her he gave a cry and dropped to the ground, with the blood +running freely down his face. At his fall the guardsmen took to +their heels in one direction and the loungers in the other, while +a number of better-dressed people, who had watched the scuffle +without taking part in it, crowded in to help the lady and to +attend to the injured man. Irene Adler, as I will still call her, +had hurried up the steps; but she stood at the top with her +superb figure outlined against the lights of the hall, looking +back into the street. + +"Is the poor gentleman much hurt?" she asked. + +"He is dead," cried several voices. + +"No, no, there's life in him!" shouted another. "But he'll be +gone before you can get him to hospital." + +"He's a brave fellow," said a woman. "They would have had the +lady's purse and watch if it hadn't been for him. They were a +gang, and a rough one, too. Ah, he's breathing now." + +"He can't lie in the street. May we bring him in, marm?" + +"Surely. Bring him into the sitting-room. There is a comfortable +sofa. This way, please!" + +Slowly and solemnly he was borne into Briony Lodge and laid out +in the principal room, while I still observed the proceedings +from my post by the window. The lamps had been lit, but the +blinds had not been drawn, so that I could see Holmes as he lay +upon the couch. I do not know whether he was seized with +compunction at that moment for the part he was playing, but I +know that I never felt more heartily ashamed of myself in my life +than when I saw the beautiful creature against whom I was +conspiring, or the grace and kindliness with which she waited +upon the injured man. And yet it would be the blackest treachery +to Holmes to draw back now from the part which he had intrusted +to me. I hardened my heart, and took the smoke-rocket from under +my ulster. After all, I thought, we are not injuring her. We are +but preventing her from injuring another. + +Holmes had sat up upon the couch, and I saw him motion like a man +who is in need of air. A maid rushed across and threw open the +window. At the same instant I saw him raise his hand and at the +signal I tossed my rocket into the room with a cry of "Fire!" The +word was no sooner out of my mouth than the whole crowd of +spectators, well dressed and ill--gentlemen, ostlers, and +servant-maids--joined in a general shriek of "Fire!" Thick clouds +of smoke curled through the room and out at the open window. I +caught a glimpse of rushing figures, and a moment later the voice +of Holmes from within assuring them that it was a false alarm. +Slipping through the shouting crowd I made my way to the corner +of the street, and in ten minutes was rejoiced to find my +friend's arm in mine, and to get away from the scene of uproar. +He walked swiftly and in silence for some few minutes until we +had turned down one of the quiet streets which lead towards the +Edgeware Road. + +"You did it very nicely, Doctor," he remarked. "Nothing could +have been better. It is all right." + +"You have the photograph?" + +"I know where it is." + +"And how did you find out?" + +"She showed me, as I told you she would." + +"I am still in the dark." + +"I do not wish to make a mystery," said he, laughing. "The matter +was perfectly simple. You, of course, saw that everyone in the +street was an accomplice. They were all engaged for the evening." + +"I guessed as much." + +"Then, when the row broke out, I had a little moist red paint in +the palm of my hand. I rushed forward, fell down, clapped my hand +to my face, and became a piteous spectacle. It is an old trick." + +"That also I could fathom." + +"Then they carried me in. She was bound to have me in. What else +could she do? And into her sitting-room, which was the very room +which I suspected. It lay between that and her bedroom, and I was +determined to see which. They laid me on a couch, I motioned for +air, they were compelled to open the window, and you had your +chance." + +"How did that help you?" + +"It was all-important. When a woman thinks that her house is on +fire, her instinct is at once to rush to the thing which she +values most. It is a perfectly overpowering impulse, and I have +more than once taken advantage of it. In the case of the +Darlington substitution scandal it was of use to me, and also in +the Arnsworth Castle business. A married woman grabs at her baby; +an unmarried one reaches for her jewel-box. Now it was clear to +me that our lady of to-day had nothing in the house more precious +to her than what we are in quest of. She would rush to secure it. +The alarm of fire was admirably done. The smoke and shouting were +enough to shake nerves of steel. She responded beautifully. The +photograph is in a recess behind a sliding panel just above the +right bell-pull. She was there in an instant, and I caught a +glimpse of it as she half-drew it out. When I cried out that it +was a false alarm, she replaced it, glanced at the rocket, rushed +from the room, and I have not seen her since. I rose, and, making +my excuses, escaped from the house. I hesitated whether to +attempt to secure the photograph at once; but the coachman had +come in, and as he was watching me narrowly it seemed safer to +wait. A little over-precipitance may ruin all." + +"And now?" I asked. + +"Our quest is practically finished. I shall call with the King +to-morrow, and with you, if you care to come with us. We will be +shown into the sitting-room to wait for the lady, but it is +probable that when she comes she may find neither us nor the +photograph. It might be a satisfaction to his Majesty to regain +it with his own hands." + +"And when will you call?" + +"At eight in the morning. She will not be up, so that we shall +have a clear field. Besides, we must be prompt, for this marriage +may mean a complete change in her life and habits. I must wire to +the King without delay." + +We had reached Baker Street and had stopped at the door. He was +searching his pockets for the key when someone passing said: + +"Good-night, Mister Sherlock Holmes." + +There were several people on the pavement at the time, but the +greeting appeared to come from a slim youth in an ulster who had +hurried by. + +"I've heard that voice before," said Holmes, staring down the +dimly lit street. "Now, I wonder who the deuce that could have +been." + + +III. + +I slept at Baker Street that night, and we were engaged upon our +toast and coffee in the morning when the King of Bohemia rushed +into the room. + +"You have really got it!" he cried, grasping Sherlock Holmes by +either shoulder and looking eagerly into his face. + +"Not yet." + +"But you have hopes?" + +"I have hopes." + +"Then, come. I am all impatience to be gone." + +"We must have a cab." + +"No, my brougham is waiting." + +"Then that will simplify matters." We descended and started off +once more for Briony Lodge. + +"Irene Adler is married," remarked Holmes. + +"Married! When?" + +"Yesterday." + +"But to whom?" + +"To an English lawyer named Norton." + +"But she could not love him." + +"I am in hopes that she does." + +"And why in hopes?" + +"Because it would spare your Majesty all fear of future +annoyance. If the lady loves her husband, she does not love your +Majesty. If she does not love your Majesty, there is no reason +why she should interfere with your Majesty's plan." + +"It is true. And yet--Well! I wish she had been of my own +station! What a queen she would have made!" He relapsed into a +moody silence, which was not broken until we drew up in +Serpentine Avenue. + +The door of Briony Lodge was open, and an elderly woman stood +upon the steps. She watched us with a sardonic eye as we stepped +from the brougham. + +"Mr. Sherlock Holmes, I believe?" said she. + +"I am Mr. Holmes," answered my companion, looking at her with a +questioning and rather startled gaze. + +"Indeed! My mistress told me that you were likely to call. She +left this morning with her husband by the 5:15 train from Charing +Cross for the Continent." + +"What!" Sherlock Holmes staggered back, white with chagrin and +surprise. "Do you mean that she has left England?" + +"Never to return." + +"And the papers?" asked the King hoarsely. "All is lost." + +"We shall see." He pushed past the servant and rushed into the +drawing-room, followed by the King and myself. The furniture was +scattered about in every direction, with dismantled shelves and +open drawers, as if the lady had hurriedly ransacked them before +her flight. Holmes rushed at the bell-pull, tore back a small +sliding shutter, and, plunging in his hand, pulled out a +photograph and a letter. The photograph was of Irene Adler +herself in evening dress, the letter was superscribed to +"Sherlock Holmes, Esq. To be left till called for." My friend +tore it open and we all three read it together. It was dated at +midnight of the preceding night and ran in this way: + +"MY DEAR MR. SHERLOCK HOLMES,--You really did it very well. You +took me in completely. Until after the alarm of fire, I had not a +suspicion. But then, when I found how I had betrayed myself, I +began to think. I had been warned against you months ago. I had +been told that if the King employed an agent it would certainly +be you. And your address had been given me. Yet, with all this, +you made me reveal what you wanted to know. Even after I became +suspicious, I found it hard to think evil of such a dear, kind +old clergyman. But, you know, I have been trained as an actress +myself. Male costume is nothing new to me. I often take advantage +of the freedom which it gives. I sent John, the coachman, to +watch you, ran up stairs, got into my walking-clothes, as I call +them, and came down just as you departed. + +"Well, I followed you to your door, and so made sure that I was +really an object of interest to the celebrated Mr. Sherlock +Holmes. Then I, rather imprudently, wished you good-night, and +started for the Temple to see my husband. + +"We both thought the best resource was flight, when pursued by +so formidable an antagonist; so you will find the nest empty when +you call to-morrow. As to the photograph, your client may rest in +peace. I love and am loved by a better man than he. The King may +do what he will without hindrance from one whom he has cruelly +wronged. I keep it only to safeguard myself, and to preserve a +weapon which will always secure me from any steps which he might +take in the future. I leave a photograph which he might care to +possess; and I remain, dear Mr. Sherlock Holmes, + + "Very truly yours, + "IRENE NORTON, née ADLER." + +"What a woman--oh, what a woman!" cried the King of Bohemia, when +we had all three read this epistle. "Did I not tell you how quick +and resolute she was? Would she not have made an admirable queen? +Is it not a pity that she was not on my level?" + +"From what I have seen of the lady she seems indeed to be on a +very different level to your Majesty," said Holmes coldly. "I am +sorry that I have not been able to bring your Majesty's business +to a more successful conclusion." + +"On the contrary, my dear sir," cried the King; "nothing could be +more successful. I know that her word is inviolate. The +photograph is now as safe as if it were in the fire." + +"I am glad to hear your Majesty say so." + +"I am immensely indebted to you. Pray tell me in what way I can +reward you. This ring--" He slipped an emerald snake ring from +his finger and held it out upon the palm of his hand. + +"Your Majesty has something which I should value even more +highly," said Holmes. + +"You have but to name it." + +"This photograph!" + +The King stared at him in amazement. + +"Irene's photograph!" he cried. "Certainly, if you wish it." + +"I thank your Majesty. Then there is no more to be done in the +matter. I have the honour to wish you a very good-morning." He +bowed, and, turning away without observing the hand which the +King had stretched out to him, he set off in my company for his +chambers. + +And that was how a great scandal threatened to affect the kingdom +of Bohemia, and how the best plans of Mr. Sherlock Holmes were +beaten by a woman's wit. He used to make merry over the +cleverness of women, but I have not heard him do it of late. And +when he speaks of Irene Adler, or when he refers to her +photograph, it is always under the honourable title of the woman. + + + +ADVENTURE II. THE RED-HEADED LEAGUE + +I had called upon my friend, Mr. Sherlock Holmes, one day in the +autumn of last year and found him in deep conversation with a +very stout, florid-faced, elderly gentleman with fiery red hair. +With an apology for my intrusion, I was about to withdraw when +Holmes pulled me abruptly into the room and closed the door +behind me. + +"You could not possibly have come at a better time, my dear +Watson," he said cordially. + +"I was afraid that you were engaged." + +"So I am. Very much so." + +"Then I can wait in the next room." + +"Not at all. This gentleman, Mr. Wilson, has been my partner and +helper in many of my most successful cases, and I have no +doubt that he will be of the utmost use to me in yours also." + +The stout gentleman half rose from his chair and gave a bob of +greeting, with a quick little questioning glance from his small +fat-encircled eyes. + +"Try the settee," said Holmes, relapsing into his armchair and +putting his fingertips together, as was his custom when in +judicial moods. "I know, my dear Watson, that you share my love +of all that is bizarre and outside the conventions and humdrum +routine of everyday life. You have shown your relish for it by +the enthusiasm which has prompted you to chronicle, and, if you +will excuse my saying so, somewhat to embellish so many of my own +little adventures." + +"Your cases have indeed been of the greatest interest to me," I +observed. + +"You will remember that I remarked the other day, just before we +went into the very simple problem presented by Miss Mary +Sutherland, that for strange effects and extraordinary +combinations we must go to life itself, which is always far more +daring than any effort of the imagination." + +"A proposition which I took the liberty of doubting." + +"You did, Doctor, but none the less you must come round to my +view, for otherwise I shall keep on piling fact upon fact on you +until your reason breaks down under them and acknowledges me to +be right. Now, Mr. Jabez Wilson here has been good enough to call +upon me this morning, and to begin a narrative which promises to +be one of the most singular which I have listened to for some +time. You have heard me remark that the strangest and most unique +things are very often connected not with the larger but with the +smaller crimes, and occasionally, indeed, where there is room for +doubt whether any positive crime has been committed. As far as I +have heard it is impossible for me to say whether the present +case is an instance of crime or not, but the course of events is +certainly among the most singular that I have ever listened to. +Perhaps, Mr. Wilson, you would have the great kindness to +recommence your narrative. I ask you not merely because my friend +Dr. Watson has not heard the opening part but also because the +peculiar nature of the story makes me anxious to have every +possible detail from your lips. As a rule, when I have heard some +slight indication of the course of events, I am able to guide +myself by the thousands of other similar cases which occur to my +memory. In the present instance I am forced to admit that the +facts are, to the best of my belief, unique." + +The portly client puffed out his chest with an appearance of some +little pride and pulled a dirty and wrinkled newspaper from the +inside pocket of his greatcoat. As he glanced down the +advertisement column, with his head thrust forward and the paper +flattened out upon his knee, I took a good look at the man and +endeavoured, after the fashion of my companion, to read the +indications which might be presented by his dress or appearance. + +I did not gain very much, however, by my inspection. Our visitor +bore every mark of being an average commonplace British +tradesman, obese, pompous, and slow. He wore rather baggy grey +shepherd's check trousers, a not over-clean black frock-coat, +unbuttoned in the front, and a drab waistcoat with a heavy brassy +Albert chain, and a square pierced bit of metal dangling down as +an ornament. A frayed top-hat and a faded brown overcoat with a +wrinkled velvet collar lay upon a chair beside him. Altogether, +look as I would, there was nothing remarkable about the man save +his blazing red head, and the expression of extreme chagrin and +discontent upon his features. + +Sherlock Holmes' quick eye took in my occupation, and he shook +his head with a smile as he noticed my questioning glances. +"Beyond the obvious facts that he has at some time done manual +labour, that he takes snuff, that he is a Freemason, that he has +been in China, and that he has done a considerable amount of +writing lately, I can deduce nothing else." + +Mr. Jabez Wilson started up in his chair, with his forefinger +upon the paper, but his eyes upon my companion. + +"How, in the name of good-fortune, did you know all that, Mr. +Holmes?" he asked. "How did you know, for example, that I did +manual labour. It's as true as gospel, for I began as a ship's +carpenter." + +"Your hands, my dear sir. Your right hand is quite a size larger +than your left. You have worked with it, and the muscles are more +developed." + +"Well, the snuff, then, and the Freemasonry?" + +"I won't insult your intelligence by telling you how I read that, +especially as, rather against the strict rules of your order, you +use an arc-and-compass breastpin." + +"Ah, of course, I forgot that. But the writing?" + +"What else can be indicated by that right cuff so very shiny for +five inches, and the left one with the smooth patch near the +elbow where you rest it upon the desk?" + +"Well, but China?" + +"The fish that you have tattooed immediately above your right +wrist could only have been done in China. I have made a small +study of tattoo marks and have even contributed to the literature +of the subject. That trick of staining the fishes' scales of a +delicate pink is quite peculiar to China. When, in addition, I +see a Chinese coin hanging from your watch-chain, the matter +becomes even more simple." + +Mr. Jabez Wilson laughed heavily. "Well, I never!" said he. "I +thought at first that you had done something clever, but I see +that there was nothing in it, after all." + +"I begin to think, Watson," said Holmes, "that I make a mistake +in explaining. 'Omne ignotum pro magnifico,' you know, and my +poor little reputation, such as it is, will suffer shipwreck if I +am so candid. Can you not find the advertisement, Mr. Wilson?" + +"Yes, I have got it now," he answered with his thick red finger +planted halfway down the column. "Here it is. This is what began +it all. You just read it for yourself, sir." + +I took the paper from him and read as follows: + +"TO THE RED-HEADED LEAGUE: On account of the bequest of the late +Ezekiah Hopkins, of Lebanon, Pennsylvania, U. S. A., there is now +another vacancy open which entitles a member of the League to a +salary of 4 pounds a week for purely nominal services. All +red-headed men who are sound in body and mind and above the age +of twenty-one years, are eligible. Apply in person on Monday, at +eleven o'clock, to Duncan Ross, at the offices of the League, 7 +Pope's Court, Fleet Street." + +"What on earth does this mean?" I ejaculated after I had twice +read over the extraordinary announcement. + +Holmes chuckled and wriggled in his chair, as was his habit when +in high spirits. "It is a little off the beaten track, isn't it?" +said he. "And now, Mr. Wilson, off you go at scratch and tell us +all about yourself, your household, and the effect which this +advertisement had upon your fortunes. You will first make a note, +Doctor, of the paper and the date." + +"It is The Morning Chronicle of April 27, 1890. Just two months +ago." + +"Very good. Now, Mr. Wilson?" + +"Well, it is just as I have been telling you, Mr. Sherlock +Holmes," said Jabez Wilson, mopping his forehead; "I have a small +pawnbroker's business at Coburg Square, near the City. It's not a +very large affair, and of late years it has not done more than +just give me a living. I used to be able to keep two assistants, +but now I only keep one; and I would have a job to pay him but +that he is willing to come for half wages so as to learn the +business." + +"What is the name of this obliging youth?" asked Sherlock Holmes. + +"His name is Vincent Spaulding, and he's not such a youth, +either. It's hard to say his age. I should not wish a smarter +assistant, Mr. Holmes; and I know very well that he could better +himself and earn twice what I am able to give him. But, after +all, if he is satisfied, why should I put ideas in his head?" + +"Why, indeed? You seem most fortunate in having an employé who +comes under the full market price. It is not a common experience +among employers in this age. I don't know that your assistant is +not as remarkable as your advertisement." + +"Oh, he has his faults, too," said Mr. Wilson. "Never was such a +fellow for photography. Snapping away with a camera when he ought +to be improving his mind, and then diving down into the cellar +like a rabbit into its hole to develop his pictures. That is his +main fault, but on the whole he's a good worker. There's no vice +in him." + +"He is still with you, I presume?" + +"Yes, sir. He and a girl of fourteen, who does a bit of simple +cooking and keeps the place clean--that's all I have in the +house, for I am a widower and never had any family. We live very +quietly, sir, the three of us; and we keep a roof over our heads +and pay our debts, if we do nothing more. + +"The first thing that put us out was that advertisement. +Spaulding, he came down into the office just this day eight +weeks, with this very paper in his hand, and he says: + +"'I wish to the Lord, Mr. Wilson, that I was a red-headed man.' + +"'Why that?' I asks. + +"'Why,' says he, 'here's another vacancy on the League of the +Red-headed Men. It's worth quite a little fortune to any man who +gets it, and I understand that there are more vacancies than +there are men, so that the trustees are at their wits' end what +to do with the money. If my hair would only change colour, here's +a nice little crib all ready for me to step into.' + +"'Why, what is it, then?' I asked. You see, Mr. Holmes, I am a +very stay-at-home man, and as my business came to me instead of +my having to go to it, I was often weeks on end without putting +my foot over the door-mat. In that way I didn't know much of what +was going on outside, and I was always glad of a bit of news. + +"'Have you never heard of the League of the Red-headed Men?' he +asked with his eyes open. + +"'Never.' + +"'Why, I wonder at that, for you are eligible yourself for one +of the vacancies.' + +"'And what are they worth?' I asked. + +"'Oh, merely a couple of hundred a year, but the work is slight, +and it need not interfere very much with one's other +occupations.' + +"Well, you can easily think that that made me prick up my ears, +for the business has not been over-good for some years, and an +extra couple of hundred would have been very handy. + +"'Tell me all about it,' said I. + +"'Well,' said he, showing me the advertisement, 'you can see for +yourself that the League has a vacancy, and there is the address +where you should apply for particulars. As far as I can make out, +the League was founded by an American millionaire, Ezekiah +Hopkins, who was very peculiar in his ways. He was himself +red-headed, and he had a great sympathy for all red-headed men; +so when he died it was found that he had left his enormous +fortune in the hands of trustees, with instructions to apply the +interest to the providing of easy berths to men whose hair is of +that colour. From all I hear it is splendid pay and very little to +do.' + +"'But,' said I, 'there would be millions of red-headed men who +would apply.' + +"'Not so many as you might think,' he answered. 'You see it is +really confined to Londoners, and to grown men. This American had +started from London when he was young, and he wanted to do the +old town a good turn. Then, again, I have heard it is no use your +applying if your hair is light red, or dark red, or anything but +real bright, blazing, fiery red. Now, if you cared to apply, Mr. +Wilson, you would just walk in; but perhaps it would hardly be +worth your while to put yourself out of the way for the sake of a +few hundred pounds.' + +"Now, it is a fact, gentlemen, as you may see for yourselves, +that my hair is of a very full and rich tint, so that it seemed +to me that if there was to be any competition in the matter I +stood as good a chance as any man that I had ever met. Vincent +Spaulding seemed to know so much about it that I thought he might +prove useful, so I just ordered him to put up the shutters for +the day and to come right away with me. He was very willing to +have a holiday, so we shut the business up and started off for +the address that was given us in the advertisement. + +"I never hope to see such a sight as that again, Mr. Holmes. From +north, south, east, and west every man who had a shade of red in +his hair had tramped into the city to answer the advertisement. +Fleet Street was choked with red-headed folk, and Pope's Court +looked like a coster's orange barrow. I should not have thought +there were so many in the whole country as were brought together +by that single advertisement. Every shade of colour they +were--straw, lemon, orange, brick, Irish-setter, liver, clay; +but, as Spaulding said, there were not many who had the real +vivid flame-coloured tint. When I saw how many were waiting, I +would have given it up in despair; but Spaulding would not hear +of it. How he did it I could not imagine, but he pushed and +pulled and butted until he got me through the crowd, and right up +to the steps which led to the office. There was a double stream +upon the stair, some going up in hope, and some coming back +dejected; but we wedged in as well as we could and soon found +ourselves in the office." + +"Your experience has been a most entertaining one," remarked +Holmes as his client paused and refreshed his memory with a huge +pinch of snuff. "Pray continue your very interesting statement." + +"There was nothing in the office but a couple of wooden chairs +and a deal table, behind which sat a small man with a head that +was even redder than mine. He said a few words to each candidate +as he came up, and then he always managed to find some fault in +them which would disqualify them. Getting a vacancy did not seem +to be such a very easy matter, after all. However, when our turn +came the little man was much more favourable to me than to any of +the others, and he closed the door as we entered, so that he +might have a private word with us. + +"'This is Mr. Jabez Wilson,' said my assistant, 'and he is +willing to fill a vacancy in the League.' + +"'And he is admirably suited for it,' the other answered. 'He has +every requirement. I cannot recall when I have seen anything so +fine.' He took a step backward, cocked his head on one side, and +gazed at my hair until I felt quite bashful. Then suddenly he +plunged forward, wrung my hand, and congratulated me warmly on my +success. + +"'It would be injustice to hesitate,' said he. 'You will, +however, I am sure, excuse me for taking an obvious precaution.' +With that he seized my hair in both his hands, and tugged until I +yelled with the pain. 'There is water in your eyes,' said he as +he released me. 'I perceive that all is as it should be. But we +have to be careful, for we have twice been deceived by wigs and +once by paint. I could tell you tales of cobbler's wax which +would disgust you with human nature.' He stepped over to the +window and shouted through it at the top of his voice that the +vacancy was filled. A groan of disappointment came up from below, +and the folk all trooped away in different directions until there +was not a red-head to be seen except my own and that of the +manager. + +"'My name,' said he, 'is Mr. Duncan Ross, and I am myself one of +the pensioners upon the fund left by our noble benefactor. Are +you a married man, Mr. Wilson? Have you a family?' + +"I answered that I had not. + +"His face fell immediately. + +"'Dear me!' he said gravely, 'that is very serious indeed! I am +sorry to hear you say that. The fund was, of course, for the +propagation and spread of the red-heads as well as for their +maintenance. It is exceedingly unfortunate that you should be a +bachelor.' + +"My face lengthened at this, Mr. Holmes, for I thought that I was +not to have the vacancy after all; but after thinking it over for +a few minutes he said that it would be all right. + +"'In the case of another,' said he, 'the objection might be +fatal, but we must stretch a point in favour of a man with such a +head of hair as yours. When shall you be able to enter upon your +new duties?' + +"'Well, it is a little awkward, for I have a business already,' +said I. + +"'Oh, never mind about that, Mr. Wilson!' said Vincent Spaulding. +'I should be able to look after that for you.' + +"'What would be the hours?' I asked. + +"'Ten to two.' + +"Now a pawnbroker's business is mostly done of an evening, Mr. +Holmes, especially Thursday and Friday evening, which is just +before pay-day; so it would suit me very well to earn a little in +the mornings. Besides, I knew that my assistant was a good man, +and that he would see to anything that turned up. + +"'That would suit me very well,' said I. 'And the pay?' + +"'Is 4 pounds a week.' + +"'And the work?' + +"'Is purely nominal.' + +"'What do you call purely nominal?' + +"'Well, you have to be in the office, or at least in the +building, the whole time. If you leave, you forfeit your whole +position forever. The will is very clear upon that point. You +don't comply with the conditions if you budge from the office +during that time.' + +"'It's only four hours a day, and I should not think of leaving,' +said I. + +"'No excuse will avail,' said Mr. Duncan Ross; 'neither sickness +nor business nor anything else. There you must stay, or you lose +your billet.' + +"'And the work?' + +"'Is to copy out the "Encyclopaedia Britannica." There is the first +volume of it in that press. You must find your own ink, pens, and +blotting-paper, but we provide this table and chair. Will you be +ready to-morrow?' + +"'Certainly,' I answered. + +"'Then, good-bye, Mr. Jabez Wilson, and let me congratulate you +once more on the important position which you have been fortunate +enough to gain.' He bowed me out of the room and I went home with +my assistant, hardly knowing what to say or do, I was so pleased +at my own good fortune. + +"Well, I thought over the matter all day, and by evening I was in +low spirits again; for I had quite persuaded myself that the +whole affair must be some great hoax or fraud, though what its +object might be I could not imagine. It seemed altogether past +belief that anyone could make such a will, or that they would pay +such a sum for doing anything so simple as copying out the +'Encyclopaedia Britannica.' Vincent Spaulding did what he could to +cheer me up, but by bedtime I had reasoned myself out of the +whole thing. However, in the morning I determined to have a look +at it anyhow, so I bought a penny bottle of ink, and with a +quill-pen, and seven sheets of foolscap paper, I started off for +Pope's Court. + +"Well, to my surprise and delight, everything was as right as +possible. The table was set out ready for me, and Mr. Duncan Ross +was there to see that I got fairly to work. He started me off +upon the letter A, and then he left me; but he would drop in from +time to time to see that all was right with me. At two o'clock he +bade me good-day, complimented me upon the amount that I had +written, and locked the door of the office after me. + +"This went on day after day, Mr. Holmes, and on Saturday the +manager came in and planked down four golden sovereigns for my +week's work. It was the same next week, and the same the week +after. Every morning I was there at ten, and every afternoon I +left at two. By degrees Mr. Duncan Ross took to coming in only +once of a morning, and then, after a time, he did not come in at +all. Still, of course, I never dared to leave the room for an +instant, for I was not sure when he might come, and the billet +was such a good one, and suited me so well, that I would not risk +the loss of it. + +"Eight weeks passed away like this, and I had written about +Abbots and Archery and Armour and Architecture and Attica, and +hoped with diligence that I might get on to the B's before very +long. It cost me something in foolscap, and I had pretty nearly +filled a shelf with my writings. And then suddenly the whole +business came to an end." + +"To an end?" + +"Yes, sir. And no later than this morning. I went to my work as +usual at ten o'clock, but the door was shut and locked, with a +little square of cardboard hammered on to the middle of the +panel with a tack. Here it is, and you can read for yourself." + +He held up a piece of white cardboard about the size of a sheet +of note-paper. It read in this fashion: + + THE RED-HEADED LEAGUE + + IS + + DISSOLVED. + + October 9, 1890. + +Sherlock Holmes and I surveyed this curt announcement and the +rueful face behind it, until the comical side of the affair so +completely overtopped every other consideration that we both +burst out into a roar of laughter. + +"I cannot see that there is anything very funny," cried our +client, flushing up to the roots of his flaming head. "If you can +do nothing better than laugh at me, I can go elsewhere." + +"No, no," cried Holmes, shoving him back into the chair from +which he had half risen. "I really wouldn't miss your case for +the world. It is most refreshingly unusual. But there is, if you +will excuse my saying so, something just a little funny about it. +Pray what steps did you take when you found the card upon the +door?" + +"I was staggered, sir. I did not know what to do. Then I called +at the offices round, but none of them seemed to know anything +about it. Finally, I went to the landlord, who is an accountant +living on the ground-floor, and I asked him if he could tell me +what had become of the Red-headed League. He said that he had +never heard of any such body. Then I asked him who Mr. Duncan +Ross was. He answered that the name was new to him. + +"'Well,' said I, 'the gentleman at No. 4.' + +"'What, the red-headed man?' + +"'Yes.' + +"'Oh,' said he, 'his name was William Morris. He was a solicitor +and was using my room as a temporary convenience until his new +premises were ready. He moved out yesterday.' + +"'Where could I find him?' + +"'Oh, at his new offices. He did tell me the address. Yes, 17 +King Edward Street, near St. Paul's.' + +"I started off, Mr. Holmes, but when I got to that address it was +a manufactory of artificial knee-caps, and no one in it had ever +heard of either Mr. William Morris or Mr. Duncan Ross." + +"And what did you do then?" asked Holmes. + +"I went home to Saxe-Coburg Square, and I took the advice of my +assistant. But he could not help me in any way. He could only say +that if I waited I should hear by post. But that was not quite +good enough, Mr. Holmes. I did not wish to lose such a place +without a struggle, so, as I had heard that you were good enough +to give advice to poor folk who were in need of it, I came right +away to you." + +"And you did very wisely," said Holmes. "Your case is an +exceedingly remarkable one, and I shall be happy to look into it. +From what you have told me I think that it is possible that +graver issues hang from it than might at first sight appear." + +"Grave enough!" said Mr. Jabez Wilson. "Why, I have lost four +pound a week." + +"As far as you are personally concerned," remarked Holmes, "I do +not see that you have any grievance against this extraordinary +league. On the contrary, you are, as I understand, richer by some +30 pounds, to say nothing of the minute knowledge which you have +gained on every subject which comes under the letter A. You have +lost nothing by them." + +"No, sir. But I want to find out about them, and who they are, +and what their object was in playing this prank--if it was a +prank--upon me. It was a pretty expensive joke for them, for it +cost them two and thirty pounds." + +"We shall endeavour to clear up these points for you. And, first, +one or two questions, Mr. Wilson. This assistant of yours who +first called your attention to the advertisement--how long had he +been with you?" + +"About a month then." + +"How did he come?" + +"In answer to an advertisement." + +"Was he the only applicant?" + +"No, I had a dozen." + +"Why did you pick him?" + +"Because he was handy and would come cheap." + +"At half-wages, in fact." + +"Yes." + +"What is he like, this Vincent Spaulding?" + +"Small, stout-built, very quick in his ways, no hair on his face, +though he's not short of thirty. Has a white splash of acid upon +his forehead." + +Holmes sat up in his chair in considerable excitement. "I thought +as much," said he. "Have you ever observed that his ears are +pierced for earrings?" + +"Yes, sir. He told me that a gipsy had done it for him when he +was a lad." + +"Hum!" said Holmes, sinking back in deep thought. "He is still +with you?" + +"Oh, yes, sir; I have only just left him." + +"And has your business been attended to in your absence?" + +"Nothing to complain of, sir. There's never very much to do of a +morning." + +"That will do, Mr. Wilson. I shall be happy to give you an +opinion upon the subject in the course of a day or two. To-day is +Saturday, and I hope that by Monday we may come to a conclusion." + +"Well, Watson," said Holmes when our visitor had left us, "what +do you make of it all?" + +"I make nothing of it," I answered frankly. "It is a most +mysterious business." + +"As a rule," said Holmes, "the more bizarre a thing is the less +mysterious it proves to be. It is your commonplace, featureless +crimes which are really puzzling, just as a commonplace face is +the most difficult to identify. But I must be prompt over this +matter." + +"What are you going to do, then?" I asked. + +"To smoke," he answered. "It is quite a three pipe problem, and I +beg that you won't speak to me for fifty minutes." He curled +himself up in his chair, with his thin knees drawn up to his +hawk-like nose, and there he sat with his eyes closed and his +black clay pipe thrusting out like the bill of some strange bird. +I had come to the conclusion that he had dropped asleep, and +indeed was nodding myself, when he suddenly sprang out of his +chair with the gesture of a man who has made up his mind and put +his pipe down upon the mantelpiece. + +"Sarasate plays at the St. James's Hall this afternoon," he +remarked. "What do you think, Watson? Could your patients spare +you for a few hours?" + +"I have nothing to do to-day. My practice is never very +absorbing." + +"Then put on your hat and come. I am going through the City +first, and we can have some lunch on the way. I observe that +there is a good deal of German music on the programme, which is +rather more to my taste than Italian or French. It is +introspective, and I want to introspect. Come along!" + +We travelled by the Underground as far as Aldersgate; and a short +walk took us to Saxe-Coburg Square, the scene of the singular +story which we had listened to in the morning. It was a poky, +little, shabby-genteel place, where four lines of dingy +two-storied brick houses looked out into a small railed-in +enclosure, where a lawn of weedy grass and a few clumps of faded +laurel-bushes made a hard fight against a smoke-laden and +uncongenial atmosphere. Three gilt balls and a brown board with +"JABEZ WILSON" in white letters, upon a corner house, announced +the place where our red-headed client carried on his business. +Sherlock Holmes stopped in front of it with his head on one side +and looked it all over, with his eyes shining brightly between +puckered lids. Then he walked slowly up the street, and then down +again to the corner, still looking keenly at the houses. Finally +he returned to the pawnbroker's, and, having thumped vigorously +upon the pavement with his stick two or three times, he went up +to the door and knocked. It was instantly opened by a +bright-looking, clean-shaven young fellow, who asked him to step +in. + +"Thank you," said Holmes, "I only wished to ask you how you would +go from here to the Strand." + +"Third right, fourth left," answered the assistant promptly, +closing the door. + +"Smart fellow, that," observed Holmes as we walked away. "He is, +in my judgment, the fourth smartest man in London, and for daring +I am not sure that he has not a claim to be third. I have known +something of him before." + +"Evidently," said I, "Mr. Wilson's assistant counts for a good +deal in this mystery of the Red-headed League. I am sure that you +inquired your way merely in order that you might see him." + +"Not him." + +"What then?" + +"The knees of his trousers." + +"And what did you see?" + +"What I expected to see." + +"Why did you beat the pavement?" + +"My dear doctor, this is a time for observation, not for talk. We +are spies in an enemy's country. We know something of Saxe-Coburg +Square. Let us now explore the parts which lie behind it." + +The road in which we found ourselves as we turned round the +corner from the retired Saxe-Coburg Square presented as great a +contrast to it as the front of a picture does to the back. It was +one of the main arteries which conveyed the traffic of the City +to the north and west. The roadway was blocked with the immense +stream of commerce flowing in a double tide inward and outward, +while the footpaths were black with the hurrying swarm of +pedestrians. It was difficult to realise as we looked at the line +of fine shops and stately business premises that they really +abutted on the other side upon the faded and stagnant square +which we had just quitted. + +"Let me see," said Holmes, standing at the corner and glancing +along the line, "I should like just to remember the order of the +houses here. It is a hobby of mine to have an exact knowledge of +London. There is Mortimer's, the tobacconist, the little +newspaper shop, the Coburg branch of the City and Suburban Bank, +the Vegetarian Restaurant, and McFarlane's carriage-building +depot. That carries us right on to the other block. And now, +Doctor, we've done our work, so it's time we had some play. A +sandwich and a cup of coffee, and then off to violin-land, where +all is sweetness and delicacy and harmony, and there are no +red-headed clients to vex us with their conundrums." + +My friend was an enthusiastic musician, being himself not only a +very capable performer but a composer of no ordinary merit. All +the afternoon he sat in the stalls wrapped in the most perfect +happiness, gently waving his long, thin fingers in time to the +music, while his gently smiling face and his languid, dreamy eyes +were as unlike those of Holmes the sleuth-hound, Holmes the +relentless, keen-witted, ready-handed criminal agent, as it was +possible to conceive. In his singular character the dual nature +alternately asserted itself, and his extreme exactness and +astuteness represented, as I have often thought, the reaction +against the poetic and contemplative mood which occasionally +predominated in him. The swing of his nature took him from +extreme languor to devouring energy; and, as I knew well, he was +never so truly formidable as when, for days on end, he had been +lounging in his armchair amid his improvisations and his +black-letter editions. Then it was that the lust of the chase +would suddenly come upon him, and that his brilliant reasoning +power would rise to the level of intuition, until those who were +unacquainted with his methods would look askance at him as on a +man whose knowledge was not that of other mortals. When I saw him +that afternoon so enwrapped in the music at St. James's Hall I +felt that an evil time might be coming upon those whom he had set +himself to hunt down. + +"You want to go home, no doubt, Doctor," he remarked as we +emerged. + +"Yes, it would be as well." + +"And I have some business to do which will take some hours. This +business at Coburg Square is serious." + +"Why serious?" + +"A considerable crime is in contemplation. I have every reason to +believe that we shall be in time to stop it. But to-day being +Saturday rather complicates matters. I shall want your help +to-night." + +"At what time?" + +"Ten will be early enough." + +"I shall be at Baker Street at ten." + +"Very well. And, I say, Doctor, there may be some little danger, +so kindly put your army revolver in your pocket." He waved his +hand, turned on his heel, and disappeared in an instant among the +crowd. + +I trust that I am not more dense than my neighbours, but I was +always oppressed with a sense of my own stupidity in my dealings +with Sherlock Holmes. Here I had heard what he had heard, I had +seen what he had seen, and yet from his words it was evident that +he saw clearly not only what had happened but what was about to +happen, while to me the whole business was still confused and +grotesque. As I drove home to my house in Kensington I thought +over it all, from the extraordinary story of the red-headed +copier of the "Encyclopaedia" down to the visit to Saxe-Coburg +Square, and the ominous words with which he had parted from me. +What was this nocturnal expedition, and why should I go armed? +Where were we going, and what were we to do? I had the hint from +Holmes that this smooth-faced pawnbroker's assistant was a +formidable man--a man who might play a deep game. I tried to +puzzle it out, but gave it up in despair and set the matter aside +until night should bring an explanation. + +It was a quarter-past nine when I started from home and made my +way across the Park, and so through Oxford Street to Baker +Street. Two hansoms were standing at the door, and as I entered +the passage I heard the sound of voices from above. On entering +his room I found Holmes in animated conversation with two men, +one of whom I recognised as Peter Jones, the official police +agent, while the other was a long, thin, sad-faced man, with a +very shiny hat and oppressively respectable frock-coat. + +"Ha! Our party is complete," said Holmes, buttoning up his +pea-jacket and taking his heavy hunting crop from the rack. +"Watson, I think you know Mr. Jones, of Scotland Yard? Let me +introduce you to Mr. Merryweather, who is to be our companion in +to-night's adventure." + +"We're hunting in couples again, Doctor, you see," said Jones in +his consequential way. "Our friend here is a wonderful man for +starting a chase. All he wants is an old dog to help him to do +the running down." + +"I hope a wild goose may not prove to be the end of our chase," +observed Mr. Merryweather gloomily. + +"You may place considerable confidence in Mr. Holmes, sir," said +the police agent loftily. "He has his own little methods, which +are, if he won't mind my saying so, just a little too theoretical +and fantastic, but he has the makings of a detective in him. It +is not too much to say that once or twice, as in that business of +the Sholto murder and the Agra treasure, he has been more nearly +correct than the official force." + +"Oh, if you say so, Mr. Jones, it is all right," said the +stranger with deference. "Still, I confess that I miss my rubber. +It is the first Saturday night for seven-and-twenty years that I +have not had my rubber." + +"I think you will find," said Sherlock Holmes, "that you will +play for a higher stake to-night than you have ever done yet, and +that the play will be more exciting. For you, Mr. Merryweather, +the stake will be some 30,000 pounds; and for you, Jones, it will +be the man upon whom you wish to lay your hands." + +"John Clay, the murderer, thief, smasher, and forger. He's a +young man, Mr. Merryweather, but he is at the head of his +profession, and I would rather have my bracelets on him than on +any criminal in London. He's a remarkable man, is young John +Clay. His grandfather was a royal duke, and he himself has been +to Eton and Oxford. His brain is as cunning as his fingers, and +though we meet signs of him at every turn, we never know where to +find the man himself. He'll crack a crib in Scotland one week, +and be raising money to build an orphanage in Cornwall the next. +I've been on his track for years and have never set eyes on him +yet." + +"I hope that I may have the pleasure of introducing you to-night. +I've had one or two little turns also with Mr. John Clay, and I +agree with you that he is at the head of his profession. It is +past ten, however, and quite time that we started. If you two +will take the first hansom, Watson and I will follow in the +second." + +Sherlock Holmes was not very communicative during the long drive +and lay back in the cab humming the tunes which he had heard in +the afternoon. We rattled through an endless labyrinth of gas-lit +streets until we emerged into Farrington Street. + +"We are close there now," my friend remarked. "This fellow +Merryweather is a bank director, and personally interested in the +matter. I thought it as well to have Jones with us also. He is +not a bad fellow, though an absolute imbecile in his profession. +He has one positive virtue. He is as brave as a bulldog and as +tenacious as a lobster if he gets his claws upon anyone. Here we +are, and they are waiting for us." + +We had reached the same crowded thoroughfare in which we had +found ourselves in the morning. Our cabs were dismissed, and, +following the guidance of Mr. Merryweather, we passed down a +narrow passage and through a side door, which he opened for us. +Within there was a small corridor, which ended in a very massive +iron gate. This also was opened, and led down a flight of winding +stone steps, which terminated at another formidable gate. Mr. +Merryweather stopped to light a lantern, and then conducted us +down a dark, earth-smelling passage, and so, after opening a +third door, into a huge vault or cellar, which was piled all +round with crates and massive boxes. + +"You are not very vulnerable from above," Holmes remarked as he +held up the lantern and gazed about him. + +"Nor from below," said Mr. Merryweather, striking his stick upon +the flags which lined the floor. "Why, dear me, it sounds quite +hollow!" he remarked, looking up in surprise. + +"I must really ask you to be a little more quiet!" said Holmes +severely. "You have already imperilled the whole success of our +expedition. Might I beg that you would have the goodness to sit +down upon one of those boxes, and not to interfere?" + +The solemn Mr. Merryweather perched himself upon a crate, with a +very injured expression upon his face, while Holmes fell upon his +knees upon the floor and, with the lantern and a magnifying lens, +began to examine minutely the cracks between the stones. A few +seconds sufficed to satisfy him, for he sprang to his feet again +and put his glass in his pocket. + +"We have at least an hour before us," he remarked, "for they can +hardly take any steps until the good pawnbroker is safely in bed. +Then they will not lose a minute, for the sooner they do their +work the longer time they will have for their escape. We are at +present, Doctor--as no doubt you have divined--in the cellar of +the City branch of one of the principal London banks. Mr. +Merryweather is the chairman of directors, and he will explain to +you that there are reasons why the more daring criminals of +London should take a considerable interest in this cellar at +present." + +"It is our French gold," whispered the director. "We have had +several warnings that an attempt might be made upon it." + +"Your French gold?" + +"Yes. We had occasion some months ago to strengthen our resources +and borrowed for that purpose 30,000 napoleons from the Bank of +France. It has become known that we have never had occasion to +unpack the money, and that it is still lying in our cellar. The +crate upon which I sit contains 2,000 napoleons packed between +layers of lead foil. Our reserve of bullion is much larger at +present than is usually kept in a single branch office, and the +directors have had misgivings upon the subject." + +"Which were very well justified," observed Holmes. "And now it is +time that we arranged our little plans. I expect that within an +hour matters will come to a head. In the meantime Mr. +Merryweather, we must put the screen over that dark lantern." + +"And sit in the dark?" + +"I am afraid so. I had brought a pack of cards in my pocket, and +I thought that, as we were a partie carrée, you might have your +rubber after all. But I see that the enemy's preparations have +gone so far that we cannot risk the presence of a light. And, +first of all, we must choose our positions. These are daring men, +and though we shall take them at a disadvantage, they may do us +some harm unless we are careful. I shall stand behind this crate, +and do you conceal yourselves behind those. Then, when I flash a +light upon them, close in swiftly. If they fire, Watson, have no +compunction about shooting them down." + +I placed my revolver, cocked, upon the top of the wooden case +behind which I crouched. Holmes shot the slide across the front +of his lantern and left us in pitch darkness--such an absolute +darkness as I have never before experienced. The smell of hot +metal remained to assure us that the light was still there, ready +to flash out at a moment's notice. To me, with my nerves worked +up to a pitch of expectancy, there was something depressing and +subduing in the sudden gloom, and in the cold dank air of the +vault. + +"They have but one retreat," whispered Holmes. "That is back +through the house into Saxe-Coburg Square. I hope that you have +done what I asked you, Jones?" + +"I have an inspector and two officers waiting at the front door." + +"Then we have stopped all the holes. And now we must be silent +and wait." + +What a time it seemed! From comparing notes afterwards it was but +an hour and a quarter, yet it appeared to me that the night must +have almost gone and the dawn be breaking above us. My limbs +were weary and stiff, for I feared to change my position; yet my +nerves were worked up to the highest pitch of tension, and my +hearing was so acute that I could not only hear the gentle +breathing of my companions, but I could distinguish the deeper, +heavier in-breath of the bulky Jones from the thin, sighing note +of the bank director. From my position I could look over the case +in the direction of the floor. Suddenly my eyes caught the glint +of a light. + +At first it was but a lurid spark upon the stone pavement. Then +it lengthened out until it became a yellow line, and then, +without any warning or sound, a gash seemed to open and a hand +appeared, a white, almost womanly hand, which felt about in the +centre of the little area of light. For a minute or more the +hand, with its writhing fingers, protruded out of the floor. Then +it was withdrawn as suddenly as it appeared, and all was dark +again save the single lurid spark which marked a chink between +the stones. + +Its disappearance, however, was but momentary. With a rending, +tearing sound, one of the broad, white stones turned over upon +its side and left a square, gaping hole, through which streamed +the light of a lantern. Over the edge there peeped a clean-cut, +boyish face, which looked keenly about it, and then, with a hand +on either side of the aperture, drew itself shoulder-high and +waist-high, until one knee rested upon the edge. In another +instant he stood at the side of the hole and was hauling after +him a companion, lithe and small like himself, with a pale face +and a shock of very red hair. + +"It's all clear," he whispered. "Have you the chisel and the +bags? Great Scott! Jump, Archie, jump, and I'll swing for it!" + +Sherlock Holmes had sprung out and seized the intruder by the +collar. The other dived down the hole, and I heard the sound of +rending cloth as Jones clutched at his skirts. The light flashed +upon the barrel of a revolver, but Holmes' hunting crop came +down on the man's wrist, and the pistol clinked upon the stone +floor. + +"It's no use, John Clay," said Holmes blandly. "You have no +chance at all." + +"So I see," the other answered with the utmost coolness. "I fancy +that my pal is all right, though I see you have got his +coat-tails." + +"There are three men waiting for him at the door," said Holmes. + +"Oh, indeed! You seem to have done the thing very completely. I +must compliment you." + +"And I you," Holmes answered. "Your red-headed idea was very new +and effective." + +"You'll see your pal again presently," said Jones. "He's quicker +at climbing down holes than I am. Just hold out while I fix the +derbies." + +"I beg that you will not touch me with your filthy hands," +remarked our prisoner as the handcuffs clattered upon his wrists. +"You may not be aware that I have royal blood in my veins. Have +the goodness, also, when you address me always to say 'sir' and +'please.'" + +"All right," said Jones with a stare and a snigger. "Well, would +you please, sir, march upstairs, where we can get a cab to carry +your Highness to the police-station?" + +"That is better," said John Clay serenely. He made a sweeping bow +to the three of us and walked quietly off in the custody of the +detective. + +"Really, Mr. Holmes," said Mr. Merryweather as we followed them +from the cellar, "I do not know how the bank can thank you or +repay you. There is no doubt that you have detected and defeated +in the most complete manner one of the most determined attempts +at bank robbery that have ever come within my experience." + +"I have had one or two little scores of my own to settle with Mr. +John Clay," said Holmes. "I have been at some small expense over +this matter, which I shall expect the bank to refund, but beyond +that I am amply repaid by having had an experience which is in +many ways unique, and by hearing the very remarkable narrative of +the Red-headed League." + + +"You see, Watson," he explained in the early hours of the morning +as we sat over a glass of whisky and soda in Baker Street, "it +was perfectly obvious from the first that the only possible +object of this rather fantastic business of the advertisement of +the League, and the copying of the 'Encyclopaedia,' must be to get +this not over-bright pawnbroker out of the way for a number of +hours every day. It was a curious way of managing it, but, +really, it would be difficult to suggest a better. The method was +no doubt suggested to Clay's ingenious mind by the colour of his +accomplice's hair. The 4 pounds a week was a lure which must draw +him, and what was it to them, who were playing for thousands? +They put in the advertisement, one rogue has the temporary +office, the other rogue incites the man to apply for it, and +together they manage to secure his absence every morning in the +week. From the time that I heard of the assistant having come for +half wages, it was obvious to me that he had some strong motive +for securing the situation." + +"But how could you guess what the motive was?" + +"Had there been women in the house, I should have suspected a +mere vulgar intrigue. That, however, was out of the question. The +man's business was a small one, and there was nothing in his +house which could account for such elaborate preparations, and +such an expenditure as they were at. It must, then, be something +out of the house. What could it be? I thought of the assistant's +fondness for photography, and his trick of vanishing into the +cellar. The cellar! There was the end of this tangled clue. Then +I made inquiries as to this mysterious assistant and found that I +had to deal with one of the coolest and most daring criminals in +London. He was doing something in the cellar--something which +took many hours a day for months on end. What could it be, once +more? I could think of nothing save that he was running a tunnel +to some other building. + +"So far I had got when we went to visit the scene of action. I +surprised you by beating upon the pavement with my stick. I was +ascertaining whether the cellar stretched out in front or behind. +It was not in front. Then I rang the bell, and, as I hoped, the +assistant answered it. We have had some skirmishes, but we had +never set eyes upon each other before. I hardly looked at his +face. His knees were what I wished to see. You must yourself have +remarked how worn, wrinkled, and stained they were. They spoke of +those hours of burrowing. The only remaining point was what they +were burrowing for. I walked round the corner, saw the City and +Suburban Bank abutted on our friend's premises, and felt that I +had solved my problem. When you drove home after the concert I +called upon Scotland Yard and upon the chairman of the bank +directors, with the result that you have seen." + +"And how could you tell that they would make their attempt +to-night?" I asked. + +"Well, when they closed their League offices that was a sign that +they cared no longer about Mr. Jabez Wilson's presence--in other +words, that they had completed their tunnel. But it was essential +that they should use it soon, as it might be discovered, or the +bullion might be removed. Saturday would suit them better than +any other day, as it would give them two days for their escape. +For all these reasons I expected them to come to-night." + +"You reasoned it out beautifully," I exclaimed in unfeigned +admiration. "It is so long a chain, and yet every link rings +true." + +"It saved me from ennui," he answered, yawning. "Alas! I already +feel it closing in upon me. My life is spent in one long effort +to escape from the commonplaces of existence. These little +problems help me to do so." + +"And you are a benefactor of the race," said I. + +He shrugged his shoulders. "Well, perhaps, after all, it is of +some little use," he remarked. "'L'homme c'est rien--l'oeuvre +c'est tout,' as Gustave Flaubert wrote to George Sand." + + + +ADVENTURE III. A CASE OF IDENTITY + +"My dear fellow," said Sherlock Holmes as we sat on either side +of the fire in his lodgings at Baker Street, "life is infinitely +stranger than anything which the mind of man could invent. We +would not dare to conceive the things which are really mere +commonplaces of existence. If we could fly out of that window +hand in hand, hover over this great city, gently remove the +roofs, and peep in at the queer things which are going on, the +strange coincidences, the plannings, the cross-purposes, the +wonderful chains of events, working through generations, and +leading to the most outré results, it would make all fiction with +its conventionalities and foreseen conclusions most stale and +unprofitable." + +"And yet I am not convinced of it," I answered. "The cases which +come to light in the papers are, as a rule, bald enough, and +vulgar enough. We have in our police reports realism pushed to +its extreme limits, and yet the result is, it must be confessed, +neither fascinating nor artistic." + +"A certain selection and discretion must be used in producing a +realistic effect," remarked Holmes. "This is wanting in the +police report, where more stress is laid, perhaps, upon the +platitudes of the magistrate than upon the details, which to an +observer contain the vital essence of the whole matter. Depend +upon it, there is nothing so unnatural as the commonplace." + +I smiled and shook my head. "I can quite understand your thinking +so," I said. "Of course, in your position of unofficial adviser +and helper to everybody who is absolutely puzzled, throughout +three continents, you are brought in contact with all that is +strange and bizarre. But here"--I picked up the morning paper +from the ground--"let us put it to a practical test. Here is the +first heading upon which I come. 'A husband's cruelty to his +wife.' There is half a column of print, but I know without +reading it that it is all perfectly familiar to me. There is, of +course, the other woman, the drink, the push, the blow, the +bruise, the sympathetic sister or landlady. The crudest of +writers could invent nothing more crude." + +"Indeed, your example is an unfortunate one for your argument," +said Holmes, taking the paper and glancing his eye down it. "This +is the Dundas separation case, and, as it happens, I was engaged +in clearing up some small points in connection with it. The +husband was a teetotaler, there was no other woman, and the +conduct complained of was that he had drifted into the habit of +winding up every meal by taking out his false teeth and hurling +them at his wife, which, you will allow, is not an action likely +to occur to the imagination of the average story-teller. Take a +pinch of snuff, Doctor, and acknowledge that I have scored over +you in your example." + +He held out his snuffbox of old gold, with a great amethyst in +the centre of the lid. Its splendour was in such contrast to his +homely ways and simple life that I could not help commenting upon +it. + +"Ah," said he, "I forgot that I had not seen you for some weeks. +It is a little souvenir from the King of Bohemia in return for my +assistance in the case of the Irene Adler papers." + +"And the ring?" I asked, glancing at a remarkable brilliant which +sparkled upon his finger. + +"It was from the reigning family of Holland, though the matter in +which I served them was of such delicacy that I cannot confide it +even to you, who have been good enough to chronicle one or two of +my little problems." + +"And have you any on hand just now?" I asked with interest. + +"Some ten or twelve, but none which present any feature of +interest. They are important, you understand, without being +interesting. Indeed, I have found that it is usually in +unimportant matters that there is a field for the observation, +and for the quick analysis of cause and effect which gives the +charm to an investigation. The larger crimes are apt to be the +simpler, for the bigger the crime the more obvious, as a rule, is +the motive. In these cases, save for one rather intricate matter +which has been referred to me from Marseilles, there is nothing +which presents any features of interest. It is possible, however, +that I may have something better before very many minutes are +over, for this is one of my clients, or I am much mistaken." + +He had risen from his chair and was standing between the parted +blinds gazing down into the dull neutral-tinted London street. +Looking over his shoulder, I saw that on the pavement opposite +there stood a large woman with a heavy fur boa round her neck, +and a large curling red feather in a broad-brimmed hat which was +tilted in a coquettish Duchess of Devonshire fashion over her +ear. From under this great panoply she peeped up in a nervous, +hesitating fashion at our windows, while her body oscillated +backward and forward, and her fingers fidgeted with her glove +buttons. Suddenly, with a plunge, as of the swimmer who leaves +the bank, she hurried across the road, and we heard the sharp +clang of the bell. + +"I have seen those symptoms before," said Holmes, throwing his +cigarette into the fire. "Oscillation upon the pavement always +means an affaire de coeur. She would like advice, but is not sure +that the matter is not too delicate for communication. And yet +even here we may discriminate. When a woman has been seriously +wronged by a man she no longer oscillates, and the usual symptom +is a broken bell wire. Here we may take it that there is a love +matter, but that the maiden is not so much angry as perplexed, or +grieved. But here she comes in person to resolve our doubts." + +As he spoke there was a tap at the door, and the boy in buttons +entered to announce Miss Mary Sutherland, while the lady herself +loomed behind his small black figure like a full-sailed +merchant-man behind a tiny pilot boat. Sherlock Holmes welcomed +her with the easy courtesy for which he was remarkable, and, +having closed the door and bowed her into an armchair, he looked +her over in the minute and yet abstracted fashion which was +peculiar to him. + +"Do you not find," he said, "that with your short sight it is a +little trying to do so much typewriting?" + +"I did at first," she answered, "but now I know where the letters +are without looking." Then, suddenly realising the full purport +of his words, she gave a violent start and looked up, with fear +and astonishment upon her broad, good-humoured face. "You've +heard about me, Mr. Holmes," she cried, "else how could you know +all that?" + +"Never mind," said Holmes, laughing; "it is my business to know +things. Perhaps I have trained myself to see what others +overlook. If not, why should you come to consult me?" + +"I came to you, sir, because I heard of you from Mrs. Etherege, +whose husband you found so easy when the police and everyone had +given him up for dead. Oh, Mr. Holmes, I wish you would do as +much for me. I'm not rich, but still I have a hundred a year in +my own right, besides the little that I make by the machine, and +I would give it all to know what has become of Mr. Hosmer Angel." + +"Why did you come away to consult me in such a hurry?" asked +Sherlock Holmes, with his finger-tips together and his eyes to +the ceiling. + +Again a startled look came over the somewhat vacuous face of Miss +Mary Sutherland. "Yes, I did bang out of the house," she said, +"for it made me angry to see the easy way in which Mr. +Windibank--that is, my father--took it all. He would not go to +the police, and he would not go to you, and so at last, as he +would do nothing and kept on saying that there was no harm done, +it made me mad, and I just on with my things and came right away +to you." + +"Your father," said Holmes, "your stepfather, surely, since the +name is different." + +"Yes, my stepfather. I call him father, though it sounds funny, +too, for he is only five years and two months older than myself." + +"And your mother is alive?" + +"Oh, yes, mother is alive and well. I wasn't best pleased, Mr. +Holmes, when she married again so soon after father's death, and +a man who was nearly fifteen years younger than herself. Father +was a plumber in the Tottenham Court Road, and he left a tidy +business behind him, which mother carried on with Mr. Hardy, the +foreman; but when Mr. Windibank came he made her sell the +business, for he was very superior, being a traveller in wines. +They got 4700 pounds for the goodwill and interest, which wasn't +near as much as father could have got if he had been alive." + +I had expected to see Sherlock Holmes impatient under this +rambling and inconsequential narrative, but, on the contrary, he +had listened with the greatest concentration of attention. + +"Your own little income," he asked, "does it come out of the +business?" + +"Oh, no, sir. It is quite separate and was left me by my uncle +Ned in Auckland. It is in New Zealand stock, paying 4 1/2 per +cent. Two thousand five hundred pounds was the amount, but I can +only touch the interest." + +"You interest me extremely," said Holmes. "And since you draw so +large a sum as a hundred a year, with what you earn into the +bargain, you no doubt travel a little and indulge yourself in +every way. I believe that a single lady can get on very nicely +upon an income of about 60 pounds." + +"I could do with much less than that, Mr. Holmes, but you +understand that as long as I live at home I don't wish to be a +burden to them, and so they have the use of the money just while +I am staying with them. Of course, that is only just for the +time. Mr. Windibank draws my interest every quarter and pays it +over to mother, and I find that I can do pretty well with what I +earn at typewriting. It brings me twopence a sheet, and I can +often do from fifteen to twenty sheets in a day." + +"You have made your position very clear to me," said Holmes. +"This is my friend, Dr. Watson, before whom you can speak as +freely as before myself. Kindly tell us now all about your +connection with Mr. Hosmer Angel." + +A flush stole over Miss Sutherland's face, and she picked +nervously at the fringe of her jacket. "I met him first at the +gasfitters' ball," she said. "They used to send father tickets +when he was alive, and then afterwards they remembered us, and +sent them to mother. Mr. Windibank did not wish us to go. He +never did wish us to go anywhere. He would get quite mad if I +wanted so much as to join a Sunday-school treat. But this time I +was set on going, and I would go; for what right had he to +prevent? He said the folk were not fit for us to know, when all +father's friends were to be there. And he said that I had nothing +fit to wear, when I had my purple plush that I had never so much +as taken out of the drawer. At last, when nothing else would do, +he went off to France upon the business of the firm, but we went, +mother and I, with Mr. Hardy, who used to be our foreman, and it +was there I met Mr. Hosmer Angel." + +"I suppose," said Holmes, "that when Mr. Windibank came back from +France he was very annoyed at your having gone to the ball." + +"Oh, well, he was very good about it. He laughed, I remember, and +shrugged his shoulders, and said there was no use denying +anything to a woman, for she would have her way." + +"I see. Then at the gasfitters' ball you met, as I understand, a +gentleman called Mr. Hosmer Angel." + +"Yes, sir. I met him that night, and he called next day to ask if +we had got home all safe, and after that we met him--that is to +say, Mr. Holmes, I met him twice for walks, but after that father +came back again, and Mr. Hosmer Angel could not come to the house +any more." + +"No?" + +"Well, you know father didn't like anything of the sort. He +wouldn't have any visitors if he could help it, and he used to +say that a woman should be happy in her own family circle. But +then, as I used to say to mother, a woman wants her own circle to +begin with, and I had not got mine yet." + +"But how about Mr. Hosmer Angel? Did he make no attempt to see +you?" + +"Well, father was going off to France again in a week, and Hosmer +wrote and said that it would be safer and better not to see each +other until he had gone. We could write in the meantime, and he +used to write every day. I took the letters in in the morning, so +there was no need for father to know." + +"Were you engaged to the gentleman at this time?" + +"Oh, yes, Mr. Holmes. We were engaged after the first walk that +we took. Hosmer--Mr. Angel--was a cashier in an office in +Leadenhall Street--and--" + +"What office?" + +"That's the worst of it, Mr. Holmes, I don't know." + +"Where did he live, then?" + +"He slept on the premises." + +"And you don't know his address?" + +"No--except that it was Leadenhall Street." + +"Where did you address your letters, then?" + +"To the Leadenhall Street Post Office, to be left till called +for. He said that if they were sent to the office he would be +chaffed by all the other clerks about having letters from a lady, +so I offered to typewrite them, like he did his, but he wouldn't +have that, for he said that when I wrote them they seemed to come +from me, but when they were typewritten he always felt that the +machine had come between us. That will just show you how fond he +was of me, Mr. Holmes, and the little things that he would think +of." + +"It was most suggestive," said Holmes. "It has long been an axiom +of mine that the little things are infinitely the most important. +Can you remember any other little things about Mr. Hosmer Angel?" + +"He was a very shy man, Mr. Holmes. He would rather walk with me +in the evening than in the daylight, for he said that he hated to +be conspicuous. Very retiring and gentlemanly he was. Even his +voice was gentle. He'd had the quinsy and swollen glands when he +was young, he told me, and it had left him with a weak throat, +and a hesitating, whispering fashion of speech. He was always +well dressed, very neat and plain, but his eyes were weak, just +as mine are, and he wore tinted glasses against the glare." + +"Well, and what happened when Mr. Windibank, your stepfather, +returned to France?" + +"Mr. Hosmer Angel came to the house again and proposed that we +should marry before father came back. He was in dreadful earnest +and made me swear, with my hands on the Testament, that whatever +happened I would always be true to him. Mother said he was quite +right to make me swear, and that it was a sign of his passion. +Mother was all in his favour from the first and was even fonder +of him than I was. Then, when they talked of marrying within the +week, I began to ask about father; but they both said never to +mind about father, but just to tell him afterwards, and mother +said she would make it all right with him. I didn't quite like +that, Mr. Holmes. It seemed funny that I should ask his leave, as +he was only a few years older than me; but I didn't want to do +anything on the sly, so I wrote to father at Bordeaux, where the +company has its French offices, but the letter came back to me on +the very morning of the wedding." + +"It missed him, then?" + +"Yes, sir; for he had started to England just before it arrived." + +"Ha! that was unfortunate. Your wedding was arranged, then, for +the Friday. Was it to be in church?" + +"Yes, sir, but very quietly. It was to be at St. Saviour's, near +King's Cross, and we were to have breakfast afterwards at the St. +Pancras Hotel. Hosmer came for us in a hansom, but as there were +two of us he put us both into it and stepped himself into a +four-wheeler, which happened to be the only other cab in the +street. We got to the church first, and when the four-wheeler +drove up we waited for him to step out, but he never did, and +when the cabman got down from the box and looked there was no one +there! The cabman said that he could not imagine what had become +of him, for he had seen him get in with his own eyes. That was +last Friday, Mr. Holmes, and I have never seen or heard anything +since then to throw any light upon what became of him." + +"It seems to me that you have been very shamefully treated," said +Holmes. + +"Oh, no, sir! He was too good and kind to leave me so. Why, all +the morning he was saying to me that, whatever happened, I was to +be true; and that even if something quite unforeseen occurred to +separate us, I was always to remember that I was pledged to him, +and that he would claim his pledge sooner or later. It seemed +strange talk for a wedding-morning, but what has happened since +gives a meaning to it." + +"Most certainly it does. Your own opinion is, then, that some +unforeseen catastrophe has occurred to him?" + +"Yes, sir. I believe that he foresaw some danger, or else he +would not have talked so. And then I think that what he foresaw +happened." + +"But you have no notion as to what it could have been?" + +"None." + +"One more question. How did your mother take the matter?" + +"She was angry, and said that I was never to speak of the matter +again." + +"And your father? Did you tell him?" + +"Yes; and he seemed to think, with me, that something had +happened, and that I should hear of Hosmer again. As he said, +what interest could anyone have in bringing me to the doors of +the church, and then leaving me? Now, if he had borrowed my +money, or if he had married me and got my money settled on him, +there might be some reason, but Hosmer was very independent about +money and never would look at a shilling of mine. And yet, what +could have happened? And why could he not write? Oh, it drives me +half-mad to think of it, and I can't sleep a wink at night." She +pulled a little handkerchief out of her muff and began to sob +heavily into it. + +"I shall glance into the case for you," said Holmes, rising, "and +I have no doubt that we shall reach some definite result. Let the +weight of the matter rest upon me now, and do not let your mind +dwell upon it further. Above all, try to let Mr. Hosmer Angel +vanish from your memory, as he has done from your life." + +"Then you don't think I'll see him again?" + +"I fear not." + +"Then what has happened to him?" + +"You will leave that question in my hands. I should like an +accurate description of him and any letters of his which you can +spare." + +"I advertised for him in last Saturday's Chronicle," said she. +"Here is the slip and here are four letters from him." + +"Thank you. And your address?" + +"No. 31 Lyon Place, Camberwell." + +"Mr. Angel's address you never had, I understand. Where is your +father's place of business?" + +"He travels for Westhouse & Marbank, the great claret importers +of Fenchurch Street." + +"Thank you. You have made your statement very clearly. You will +leave the papers here, and remember the advice which I have given +you. Let the whole incident be a sealed book, and do not allow it +to affect your life." + +"You are very kind, Mr. Holmes, but I cannot do that. I shall be +true to Hosmer. He shall find me ready when he comes back." + +For all the preposterous hat and the vacuous face, there was +something noble in the simple faith of our visitor which +compelled our respect. She laid her little bundle of papers upon +the table and went her way, with a promise to come again whenever +she might be summoned. + +Sherlock Holmes sat silent for a few minutes with his fingertips +still pressed together, his legs stretched out in front of him, +and his gaze directed upward to the ceiling. Then he took down +from the rack the old and oily clay pipe, which was to him as a +counsellor, and, having lit it, he leaned back in his chair, with +the thick blue cloud-wreaths spinning up from him, and a look of +infinite languor in his face. + +"Quite an interesting study, that maiden," he observed. "I found +her more interesting than her little problem, which, by the way, +is rather a trite one. You will find parallel cases, if you +consult my index, in Andover in '77, and there was something of +the sort at The Hague last year. Old as is the idea, however, +there were one or two details which were new to me. But the +maiden herself was most instructive." + +"You appeared to read a good deal upon her which was quite +invisible to me," I remarked. + +"Not invisible but unnoticed, Watson. You did not know where to +look, and so you missed all that was important. I can never bring +you to realise the importance of sleeves, the suggestiveness of +thumb-nails, or the great issues that may hang from a boot-lace. +Now, what did you gather from that woman's appearance? Describe +it." + +"Well, she had a slate-coloured, broad-brimmed straw hat, with a +feather of a brickish red. Her jacket was black, with black beads +sewn upon it, and a fringe of little black jet ornaments. Her +dress was brown, rather darker than coffee colour, with a little +purple plush at the neck and sleeves. Her gloves were greyish and +were worn through at the right forefinger. Her boots I didn't +observe. She had small round, hanging gold earrings, and a +general air of being fairly well-to-do in a vulgar, comfortable, +easy-going way." + +Sherlock Holmes clapped his hands softly together and chuckled. + +"'Pon my word, Watson, you are coming along wonderfully. You have +really done very well indeed. It is true that you have missed +everything of importance, but you have hit upon the method, and +you have a quick eye for colour. Never trust to general +impressions, my boy, but concentrate yourself upon details. My +first glance is always at a woman's sleeve. In a man it is +perhaps better first to take the knee of the trouser. As you +observe, this woman had plush upon her sleeves, which is a most +useful material for showing traces. The double line a little +above the wrist, where the typewritist presses against the table, +was beautifully defined. The sewing-machine, of the hand type, +leaves a similar mark, but only on the left arm, and on the side +of it farthest from the thumb, instead of being right across the +broadest part, as this was. I then glanced at her face, and, +observing the dint of a pince-nez at either side of her nose, I +ventured a remark upon short sight and typewriting, which seemed +to surprise her." + +"It surprised me." + +"But, surely, it was obvious. I was then much surprised and +interested on glancing down to observe that, though the boots +which she was wearing were not unlike each other, they were +really odd ones; the one having a slightly decorated toe-cap, and +the other a plain one. One was buttoned only in the two lower +buttons out of five, and the other at the first, third, and +fifth. Now, when you see that a young lady, otherwise neatly +dressed, has come away from home with odd boots, half-buttoned, +it is no great deduction to say that she came away in a hurry." + +"And what else?" I asked, keenly interested, as I always was, by +my friend's incisive reasoning. + +"I noted, in passing, that she had written a note before leaving +home but after being fully dressed. You observed that her right +glove was torn at the forefinger, but you did not apparently see +that both glove and finger were stained with violet ink. She had +written in a hurry and dipped her pen too deep. It must have been +this morning, or the mark would not remain clear upon the finger. +All this is amusing, though rather elementary, but I must go back +to business, Watson. Would you mind reading me the advertised +description of Mr. Hosmer Angel?" + +I held the little printed slip to the light. + +"Missing," it said, "on the morning of the fourteenth, a gentleman +named Hosmer Angel. About five ft. seven in. in height; +strongly built, sallow complexion, black hair, a little bald in +the centre, bushy, black side-whiskers and moustache; tinted +glasses, slight infirmity of speech. Was dressed, when last seen, +in black frock-coat faced with silk, black waistcoat, gold Albert +chain, and grey Harris tweed trousers, with brown gaiters over +elastic-sided boots. Known to have been employed in an office in +Leadenhall Street. Anybody bringing--" + +"That will do," said Holmes. "As to the letters," he continued, +glancing over them, "they are very commonplace. Absolutely no +clue in them to Mr. Angel, save that he quotes Balzac once. There +is one remarkable point, however, which will no doubt strike +you." + +"They are typewritten," I remarked. + +"Not only that, but the signature is typewritten. Look at the +neat little 'Hosmer Angel' at the bottom. There is a date, you +see, but no superscription except Leadenhall Street, which is +rather vague. The point about the signature is very suggestive--in +fact, we may call it conclusive." + +"Of what?" + +"My dear fellow, is it possible you do not see how strongly it +bears upon the case?" + +"I cannot say that I do unless it were that he wished to be able +to deny his signature if an action for breach of promise were +instituted." + +"No, that was not the point. However, I shall write two letters, +which should settle the matter. One is to a firm in the City, the +other is to the young lady's stepfather, Mr. Windibank, asking +him whether he could meet us here at six o'clock tomorrow +evening. It is just as well that we should do business with the +male relatives. And now, Doctor, we can do nothing until the +answers to those letters come, so we may put our little problem +upon the shelf for the interim." + +I had had so many reasons to believe in my friend's subtle powers +of reasoning and extraordinary energy in action that I felt that +he must have some solid grounds for the assured and easy +demeanour with which he treated the singular mystery which he had +been called upon to fathom. Once only had I known him to fail, in +the case of the King of Bohemia and of the Irene Adler +photograph; but when I looked back to the weird business of the +Sign of Four, and the extraordinary circumstances connected with +the Study in Scarlet, I felt that it would be a strange tangle +indeed which he could not unravel. + +I left him then, still puffing at his black clay pipe, with the +conviction that when I came again on the next evening I would +find that he held in his hands all the clues which would lead up +to the identity of the disappearing bridegroom of Miss Mary +Sutherland. + +A professional case of great gravity was engaging my own +attention at the time, and the whole of next day I was busy at +the bedside of the sufferer. It was not until close upon six +o'clock that I found myself free and was able to spring into a +hansom and drive to Baker Street, half afraid that I might be too +late to assist at the dénouement of the little mystery. I found +Sherlock Holmes alone, however, half asleep, with his long, thin +form curled up in the recesses of his armchair. A formidable +array of bottles and test-tubes, with the pungent cleanly smell +of hydrochloric acid, told me that he had spent his day in the +chemical work which was so dear to him. + +"Well, have you solved it?" I asked as I entered. + +"Yes. It was the bisulphate of baryta." + +"No, no, the mystery!" I cried. + +"Oh, that! I thought of the salt that I have been working upon. +There was never any mystery in the matter, though, as I said +yesterday, some of the details are of interest. The only drawback +is that there is no law, I fear, that can touch the scoundrel." + +"Who was he, then, and what was his object in deserting Miss +Sutherland?" + +The question was hardly out of my mouth, and Holmes had not yet +opened his lips to reply, when we heard a heavy footfall in the +passage and a tap at the door. + +"This is the girl's stepfather, Mr. James Windibank," said +Holmes. "He has written to me to say that he would be here at +six. Come in!" + +The man who entered was a sturdy, middle-sized fellow, some +thirty years of age, clean-shaven, and sallow-skinned, with a +bland, insinuating manner, and a pair of wonderfully sharp and +penetrating grey eyes. He shot a questioning glance at each of +us, placed his shiny top-hat upon the sideboard, and with a +slight bow sidled down into the nearest chair. + +"Good-evening, Mr. James Windibank," said Holmes. "I think that +this typewritten letter is from you, in which you made an +appointment with me for six o'clock?" + +"Yes, sir. I am afraid that I am a little late, but I am not +quite my own master, you know. I am sorry that Miss Sutherland +has troubled you about this little matter, for I think it is far +better not to wash linen of the sort in public. It was quite +against my wishes that she came, but she is a very excitable, +impulsive girl, as you may have noticed, and she is not easily +controlled when she has made up her mind on a point. Of course, I +did not mind you so much, as you are not connected with the +official police, but it is not pleasant to have a family +misfortune like this noised abroad. Besides, it is a useless +expense, for how could you possibly find this Hosmer Angel?" + +"On the contrary," said Holmes quietly; "I have every reason to +believe that I will succeed in discovering Mr. Hosmer Angel." + +Mr. Windibank gave a violent start and dropped his gloves. "I am +delighted to hear it," he said. + +"It is a curious thing," remarked Holmes, "that a typewriter has +really quite as much individuality as a man's handwriting. Unless +they are quite new, no two of them write exactly alike. Some +letters get more worn than others, and some wear only on one +side. Now, you remark in this note of yours, Mr. Windibank, that +in every case there is some little slurring over of the 'e,' and +a slight defect in the tail of the 'r.' There are fourteen other +characteristics, but those are the more obvious." + +"We do all our correspondence with this machine at the office, +and no doubt it is a little worn," our visitor answered, glancing +keenly at Holmes with his bright little eyes. + +"And now I will show you what is really a very interesting study, +Mr. Windibank," Holmes continued. "I think of writing another +little monograph some of these days on the typewriter and its +relation to crime. It is a subject to which I have devoted some +little attention. I have here four letters which purport to come +from the missing man. They are all typewritten. In each case, not +only are the 'e's' slurred and the 'r's' tailless, but you will +observe, if you care to use my magnifying lens, that the fourteen +other characteristics to which I have alluded are there as well." + +Mr. Windibank sprang out of his chair and picked up his hat. "I +cannot waste time over this sort of fantastic talk, Mr. Holmes," +he said. "If you can catch the man, catch him, and let me know +when you have done it." + +"Certainly," said Holmes, stepping over and turning the key in +the door. "I let you know, then, that I have caught him!" + +"What! where?" shouted Mr. Windibank, turning white to his lips +and glancing about him like a rat in a trap. + +"Oh, it won't do--really it won't," said Holmes suavely. "There +is no possible getting out of it, Mr. Windibank. It is quite too +transparent, and it was a very bad compliment when you said that +it was impossible for me to solve so simple a question. That's +right! Sit down and let us talk it over." + +Our visitor collapsed into a chair, with a ghastly face and a +glitter of moisture on his brow. "It--it's not actionable," he +stammered. + +"I am very much afraid that it is not. But between ourselves, +Windibank, it was as cruel and selfish and heartless a trick in a +petty way as ever came before me. Now, let me just run over the +course of events, and you will contradict me if I go wrong." + +The man sat huddled up in his chair, with his head sunk upon his +breast, like one who is utterly crushed. Holmes stuck his feet up +on the corner of the mantelpiece and, leaning back with his hands +in his pockets, began talking, rather to himself, as it seemed, +than to us. + +"The man married a woman very much older than himself for her +money," said he, "and he enjoyed the use of the money of the +daughter as long as she lived with them. It was a considerable +sum, for people in their position, and the loss of it would have +made a serious difference. It was worth an effort to preserve it. +The daughter was of a good, amiable disposition, but affectionate +and warm-hearted in her ways, so that it was evident that with +her fair personal advantages, and her little income, she would +not be allowed to remain single long. Now her marriage would +mean, of course, the loss of a hundred a year, so what does her +stepfather do to prevent it? He takes the obvious course of +keeping her at home and forbidding her to seek the company of +people of her own age. But soon he found that that would not +answer forever. She became restive, insisted upon her rights, and +finally announced her positive intention of going to a certain +ball. What does her clever stepfather do then? He conceives an +idea more creditable to his head than to his heart. With the +connivance and assistance of his wife he disguised himself, +covered those keen eyes with tinted glasses, masked the face with +a moustache and a pair of bushy whiskers, sunk that clear voice +into an insinuating whisper, and doubly secure on account of the +girl's short sight, he appears as Mr. Hosmer Angel, and keeps off +other lovers by making love himself." + +"It was only a joke at first," groaned our visitor. "We never +thought that she would have been so carried away." + +"Very likely not. However that may be, the young lady was very +decidedly carried away, and, having quite made up her mind that +her stepfather was in France, the suspicion of treachery never +for an instant entered her mind. She was flattered by the +gentleman's attentions, and the effect was increased by the +loudly expressed admiration of her mother. Then Mr. Angel began +to call, for it was obvious that the matter should be pushed as +far as it would go if a real effect were to be produced. There +were meetings, and an engagement, which would finally secure the +girl's affections from turning towards anyone else. But the +deception could not be kept up forever. These pretended journeys +to France were rather cumbrous. The thing to do was clearly to +bring the business to an end in such a dramatic manner that it +would leave a permanent impression upon the young lady's mind and +prevent her from looking upon any other suitor for some time to +come. Hence those vows of fidelity exacted upon a Testament, and +hence also the allusions to a possibility of something happening +on the very morning of the wedding. James Windibank wished Miss +Sutherland to be so bound to Hosmer Angel, and so uncertain as to +his fate, that for ten years to come, at any rate, she would not +listen to another man. As far as the church door he brought her, +and then, as he could go no farther, he conveniently vanished +away by the old trick of stepping in at one door of a +four-wheeler and out at the other. I think that was the chain of +events, Mr. Windibank!" + +Our visitor had recovered something of his assurance while Holmes +had been talking, and he rose from his chair now with a cold +sneer upon his pale face. + +"It may be so, or it may not, Mr. Holmes," said he, "but if you +are so very sharp you ought to be sharp enough to know that it is +you who are breaking the law now, and not me. I have done nothing +actionable from the first, but as long as you keep that door +locked you lay yourself open to an action for assault and illegal +constraint." + +"The law cannot, as you say, touch you," said Holmes, unlocking +and throwing open the door, "yet there never was a man who +deserved punishment more. If the young lady has a brother or a +friend, he ought to lay a whip across your shoulders. By Jove!" +he continued, flushing up at the sight of the bitter sneer upon +the man's face, "it is not part of my duties to my client, but +here's a hunting crop handy, and I think I shall just treat +myself to--" He took two swift steps to the whip, but before he +could grasp it there was a wild clatter of steps upon the stairs, +the heavy hall door banged, and from the window we could see Mr. +James Windibank running at the top of his speed down the road. + +"There's a cold-blooded scoundrel!" said Holmes, laughing, as he +threw himself down into his chair once more. "That fellow will +rise from crime to crime until he does something very bad, and +ends on a gallows. The case has, in some respects, been not +entirely devoid of interest." + +"I cannot now entirely see all the steps of your reasoning," I +remarked. + +"Well, of course it was obvious from the first that this Mr. +Hosmer Angel must have some strong object for his curious +conduct, and it was equally clear that the only man who really +profited by the incident, as far as we could see, was the +stepfather. Then the fact that the two men were never together, +but that the one always appeared when the other was away, was +suggestive. So were the tinted spectacles and the curious voice, +which both hinted at a disguise, as did the bushy whiskers. My +suspicions were all confirmed by his peculiar action in +typewriting his signature, which, of course, inferred that his +handwriting was so familiar to her that she would recognise even +the smallest sample of it. You see all these isolated facts, +together with many minor ones, all pointed in the same +direction." + +"And how did you verify them?" + +"Having once spotted my man, it was easy to get corroboration. I +knew the firm for which this man worked. Having taken the printed +description. I eliminated everything from it which could be the +result of a disguise--the whiskers, the glasses, the voice, and I +sent it to the firm, with a request that they would inform me +whether it answered to the description of any of their +travellers. I had already noticed the peculiarities of the +typewriter, and I wrote to the man himself at his business +address asking him if he would come here. As I expected, his +reply was typewritten and revealed the same trivial but +characteristic defects. The same post brought me a letter from +Westhouse & Marbank, of Fenchurch Street, to say that the +description tallied in every respect with that of their employé, +James Windibank. Voilà tout!" + +"And Miss Sutherland?" + +"If I tell her she will not believe me. You may remember the old +Persian saying, 'There is danger for him who taketh the tiger +cub, and danger also for whoso snatches a delusion from a woman.' +There is as much sense in Hafiz as in Horace, and as much +knowledge of the world." + + + +ADVENTURE IV. THE BOSCOMBE VALLEY MYSTERY + +We were seated at breakfast one morning, my wife and I, when the +maid brought in a telegram. It was from Sherlock Holmes and ran +in this way: + +"Have you a couple of days to spare? Have just been wired for from +the west of England in connection with Boscombe Valley tragedy. +Shall be glad if you will come with me. Air and scenery perfect. +Leave Paddington by the 11:15." + +"What do you say, dear?" said my wife, looking across at me. +"Will you go?" + +"I really don't know what to say. I have a fairly long list at +present." + +"Oh, Anstruther would do your work for you. You have been looking +a little pale lately. I think that the change would do you good, +and you are always so interested in Mr. Sherlock Holmes' cases." + +"I should be ungrateful if I were not, seeing what I gained +through one of them," I answered. "But if I am to go, I must pack +at once, for I have only half an hour." + +My experience of camp life in Afghanistan had at least had the +effect of making me a prompt and ready traveller. My wants were +few and simple, so that in less than the time stated I was in a +cab with my valise, rattling away to Paddington Station. Sherlock +Holmes was pacing up and down the platform, his tall, gaunt +figure made even gaunter and taller by his long grey +travelling-cloak and close-fitting cloth cap. + +"It is really very good of you to come, Watson," said he. "It +makes a considerable difference to me, having someone with me on +whom I can thoroughly rely. Local aid is always either worthless +or else biassed. If you will keep the two corner seats I shall +get the tickets." + +We had the carriage to ourselves save for an immense litter of +papers which Holmes had brought with him. Among these he rummaged +and read, with intervals of note-taking and of meditation, until +we were past Reading. Then he suddenly rolled them all into a +gigantic ball and tossed them up onto the rack. + +"Have you heard anything of the case?" he asked. + +"Not a word. I have not seen a paper for some days." + +"The London press has not had very full accounts. I have just +been looking through all the recent papers in order to master the +particulars. It seems, from what I gather, to be one of those +simple cases which are so extremely difficult." + +"That sounds a little paradoxical." + +"But it is profoundly true. Singularity is almost invariably a +clue. The more featureless and commonplace a crime is, the more +difficult it is to bring it home. In this case, however, they +have established a very serious case against the son of the +murdered man." + +"It is a murder, then?" + +"Well, it is conjectured to be so. I shall take nothing for +granted until I have the opportunity of looking personally into +it. I will explain the state of things to you, as far as I have +been able to understand it, in a very few words. + +"Boscombe Valley is a country district not very far from Ross, in +Herefordshire. The largest landed proprietor in that part is a +Mr. John Turner, who made his money in Australia and returned +some years ago to the old country. One of the farms which he +held, that of Hatherley, was let to Mr. Charles McCarthy, who was +also an ex-Australian. The men had known each other in the +colonies, so that it was not unnatural that when they came to +settle down they should do so as near each other as possible. +Turner was apparently the richer man, so McCarthy became his +tenant but still remained, it seems, upon terms of perfect +equality, as they were frequently together. McCarthy had one son, +a lad of eighteen, and Turner had an only daughter of the same +age, but neither of them had wives living. They appear to have +avoided the society of the neighbouring English families and to +have led retired lives, though both the McCarthys were fond of +sport and were frequently seen at the race-meetings of the +neighbourhood. McCarthy kept two servants--a man and a girl. +Turner had a considerable household, some half-dozen at the +least. That is as much as I have been able to gather about the +families. Now for the facts. + +"On June 3rd, that is, on Monday last, McCarthy left his house at +Hatherley about three in the afternoon and walked down to the +Boscombe Pool, which is a small lake formed by the spreading out +of the stream which runs down the Boscombe Valley. He had been +out with his serving-man in the morning at Ross, and he had told +the man that he must hurry, as he had an appointment of +importance to keep at three. From that appointment he never came +back alive. + +"From Hatherley Farm-house to the Boscombe Pool is a quarter of a +mile, and two people saw him as he passed over this ground. One +was an old woman, whose name is not mentioned, and the other was +William Crowder, a game-keeper in the employ of Mr. Turner. Both +these witnesses depose that Mr. McCarthy was walking alone. The +game-keeper adds that within a few minutes of his seeing Mr. +McCarthy pass he had seen his son, Mr. James McCarthy, going the +same way with a gun under his arm. To the best of his belief, the +father was actually in sight at the time, and the son was +following him. He thought no more of the matter until he heard in +the evening of the tragedy that had occurred. + +"The two McCarthys were seen after the time when William Crowder, +the game-keeper, lost sight of them. The Boscombe Pool is thickly +wooded round, with just a fringe of grass and of reeds round the +edge. A girl of fourteen, Patience Moran, who is the daughter of +the lodge-keeper of the Boscombe Valley estate, was in one of the +woods picking flowers. She states that while she was there she +saw, at the border of the wood and close by the lake, Mr. +McCarthy and his son, and that they appeared to be having a +violent quarrel. She heard Mr. McCarthy the elder using very +strong language to his son, and she saw the latter raise up his +hand as if to strike his father. She was so frightened by their +violence that she ran away and told her mother when she reached +home that she had left the two McCarthys quarrelling near +Boscombe Pool, and that she was afraid that they were going to +fight. She had hardly said the words when young Mr. McCarthy came +running up to the lodge to say that he had found his father dead +in the wood, and to ask for the help of the lodge-keeper. He was +much excited, without either his gun or his hat, and his right +hand and sleeve were observed to be stained with fresh blood. On +following him they found the dead body stretched out upon the +grass beside the pool. The head had been beaten in by repeated +blows of some heavy and blunt weapon. The injuries were such as +might very well have been inflicted by the butt-end of his son's +gun, which was found lying on the grass within a few paces of the +body. Under these circumstances the young man was instantly +arrested, and a verdict of 'wilful murder' having been returned +at the inquest on Tuesday, he was on Wednesday brought before the +magistrates at Ross, who have referred the case to the next +Assizes. Those are the main facts of the case as they came out +before the coroner and the police-court." + +"I could hardly imagine a more damning case," I remarked. "If +ever circumstantial evidence pointed to a criminal it does so +here." + +"Circumstantial evidence is a very tricky thing," answered Holmes +thoughtfully. "It may seem to point very straight to one thing, +but if you shift your own point of view a little, you may find it +pointing in an equally uncompromising manner to something +entirely different. It must be confessed, however, that the case +looks exceedingly grave against the young man, and it is very +possible that he is indeed the culprit. There are several people +in the neighbourhood, however, and among them Miss Turner, the +daughter of the neighbouring landowner, who believe in his +innocence, and who have retained Lestrade, whom you may recollect +in connection with the Study in Scarlet, to work out the case in +his interest. Lestrade, being rather puzzled, has referred the +case to me, and hence it is that two middle-aged gentlemen are +flying westward at fifty miles an hour instead of quietly +digesting their breakfasts at home." + +"I am afraid," said I, "that the facts are so obvious that you +will find little credit to be gained out of this case." + +"There is nothing more deceptive than an obvious fact," he +answered, laughing. "Besides, we may chance to hit upon some +other obvious facts which may have been by no means obvious to +Mr. Lestrade. You know me too well to think that I am boasting +when I say that I shall either confirm or destroy his theory by +means which he is quite incapable of employing, or even of +understanding. To take the first example to hand, I very clearly +perceive that in your bedroom the window is upon the right-hand +side, and yet I question whether Mr. Lestrade would have noted +even so self-evident a thing as that." + +"How on earth--" + +"My dear fellow, I know you well. I know the military neatness +which characterises you. You shave every morning, and in this +season you shave by the sunlight; but since your shaving is less +and less complete as we get farther back on the left side, until +it becomes positively slovenly as we get round the angle of the +jaw, it is surely very clear that that side is less illuminated +than the other. I could not imagine a man of your habits looking +at himself in an equal light and being satisfied with such a +result. I only quote this as a trivial example of observation and +inference. Therein lies my métier, and it is just possible that +it may be of some service in the investigation which lies before +us. There are one or two minor points which were brought out in +the inquest, and which are worth considering." + +"What are they?" + +"It appears that his arrest did not take place at once, but after +the return to Hatherley Farm. On the inspector of constabulary +informing him that he was a prisoner, he remarked that he was not +surprised to hear it, and that it was no more than his deserts. +This observation of his had the natural effect of removing any +traces of doubt which might have remained in the minds of the +coroner's jury." + +"It was a confession," I ejaculated. + +"No, for it was followed by a protestation of innocence." + +"Coming on the top of such a damning series of events, it was at +least a most suspicious remark." + +"On the contrary," said Holmes, "it is the brightest rift which I +can at present see in the clouds. However innocent he might be, +he could not be such an absolute imbecile as not to see that the +circumstances were very black against him. Had he appeared +surprised at his own arrest, or feigned indignation at it, I +should have looked upon it as highly suspicious, because such +surprise or anger would not be natural under the circumstances, +and yet might appear to be the best policy to a scheming man. His +frank acceptance of the situation marks him as either an innocent +man, or else as a man of considerable self-restraint and +firmness. As to his remark about his deserts, it was also not +unnatural if you consider that he stood beside the dead body of +his father, and that there is no doubt that he had that very day +so far forgotten his filial duty as to bandy words with him, and +even, according to the little girl whose evidence is so +important, to raise his hand as if to strike him. The +self-reproach and contrition which are displayed in his remark +appear to me to be the signs of a healthy mind rather than of a +guilty one." + +I shook my head. "Many men have been hanged on far slighter +evidence," I remarked. + +"So they have. And many men have been wrongfully hanged." + +"What is the young man's own account of the matter?" + +"It is, I am afraid, not very encouraging to his supporters, +though there are one or two points in it which are suggestive. +You will find it here, and may read it for yourself." + +He picked out from his bundle a copy of the local Herefordshire +paper, and having turned down the sheet he pointed out the +paragraph in which the unfortunate young man had given his own +statement of what had occurred. I settled myself down in the +corner of the carriage and read it very carefully. It ran in this +way: + +"Mr. James McCarthy, the only son of the deceased, was then called +and gave evidence as follows: 'I had been away from home for +three days at Bristol, and had only just returned upon the +morning of last Monday, the 3rd. My father was absent from home at +the time of my arrival, and I was informed by the maid that he +had driven over to Ross with John Cobb, the groom. Shortly after +my return I heard the wheels of his trap in the yard, and, +looking out of my window, I saw him get out and walk rapidly out +of the yard, though I was not aware in which direction he was +going. I then took my gun and strolled out in the direction of +the Boscombe Pool, with the intention of visiting the rabbit +warren which is upon the other side. On my way I saw William +Crowder, the game-keeper, as he had stated in his evidence; but +he is mistaken in thinking that I was following my father. I had +no idea that he was in front of me. When about a hundred yards +from the pool I heard a cry of "Cooee!" which was a usual signal +between my father and myself. I then hurried forward, and found +him standing by the pool. He appeared to be much surprised at +seeing me and asked me rather roughly what I was doing there. A +conversation ensued which led to high words and almost to blows, +for my father was a man of a very violent temper. Seeing that his +passion was becoming ungovernable, I left him and returned +towards Hatherley Farm. I had not gone more than 150 yards, +however, when I heard a hideous outcry behind me, which caused me +to run back again. I found my father expiring upon the ground, +with his head terribly injured. I dropped my gun and held him in +my arms, but he almost instantly expired. I knelt beside him for +some minutes, and then made my way to Mr. Turner's lodge-keeper, +his house being the nearest, to ask for assistance. I saw no one +near my father when I returned, and I have no idea how he came by +his injuries. He was not a popular man, being somewhat cold and +forbidding in his manners, but he had, as far as I know, no +active enemies. I know nothing further of the matter.' + +"The Coroner: Did your father make any statement to you before +he died? + +"Witness: He mumbled a few words, but I could only catch some +allusion to a rat. + +"The Coroner: What did you understand by that? + +"Witness: It conveyed no meaning to me. I thought that he was +delirious. + +"The Coroner: What was the point upon which you and your father +had this final quarrel? + +"Witness: I should prefer not to answer. + +"The Coroner: I am afraid that I must press it. + +"Witness: It is really impossible for me to tell you. I can +assure you that it has nothing to do with the sad tragedy which +followed. + +"The Coroner: That is for the court to decide. I need not point +out to you that your refusal to answer will prejudice your case +considerably in any future proceedings which may arise. + +"Witness: I must still refuse. + +"The Coroner: I understand that the cry of 'Cooee' was a common +signal between you and your father? + +"Witness: It was. + +"The Coroner: How was it, then, that he uttered it before he saw +you, and before he even knew that you had returned from Bristol? + +"Witness (with considerable confusion): I do not know. + +"A Juryman: Did you see nothing which aroused your suspicions +when you returned on hearing the cry and found your father +fatally injured? + +"Witness: Nothing definite. + +"The Coroner: What do you mean? + +"Witness: I was so disturbed and excited as I rushed out into +the open, that I could think of nothing except of my father. Yet +I have a vague impression that as I ran forward something lay +upon the ground to the left of me. It seemed to me to be +something grey in colour, a coat of some sort, or a plaid perhaps. +When I rose from my father I looked round for it, but it was +gone. + +"'Do you mean that it disappeared before you went for help?' + +"'Yes, it was gone.' + +"'You cannot say what it was?' + +"'No, I had a feeling something was there.' + +"'How far from the body?' + +"'A dozen yards or so.' + +"'And how far from the edge of the wood?' + +"'About the same.' + +"'Then if it was removed it was while you were within a dozen +yards of it?' + +"'Yes, but with my back towards it.' + +"This concluded the examination of the witness." + +"I see," said I as I glanced down the column, "that the coroner +in his concluding remarks was rather severe upon young McCarthy. +He calls attention, and with reason, to the discrepancy about his +father having signalled to him before seeing him, also to his +refusal to give details of his conversation with his father, and +his singular account of his father's dying words. They are all, +as he remarks, very much against the son." + +Holmes laughed softly to himself and stretched himself out upon +the cushioned seat. "Both you and the coroner have been at some +pains," said he, "to single out the very strongest points in the +young man's favour. Don't you see that you alternately give him +credit for having too much imagination and too little? Too +little, if he could not invent a cause of quarrel which would +give him the sympathy of the jury; too much, if he evolved from +his own inner consciousness anything so outré as a dying +reference to a rat, and the incident of the vanishing cloth. No, +sir, I shall approach this case from the point of view that what +this young man says is true, and we shall see whither that +hypothesis will lead us. And now here is my pocket Petrarch, and +not another word shall I say of this case until we are on the +scene of action. We lunch at Swindon, and I see that we shall be +there in twenty minutes." + +It was nearly four o'clock when we at last, after passing through +the beautiful Stroud Valley, and over the broad gleaming Severn, +found ourselves at the pretty little country-town of Ross. A +lean, ferret-like man, furtive and sly-looking, was waiting for +us upon the platform. In spite of the light brown dustcoat and +leather-leggings which he wore in deference to his rustic +surroundings, I had no difficulty in recognising Lestrade, of +Scotland Yard. With him we drove to the Hereford Arms where a +room had already been engaged for us. + +"I have ordered a carriage," said Lestrade as we sat over a cup +of tea. "I knew your energetic nature, and that you would not be +happy until you had been on the scene of the crime." + +"It was very nice and complimentary of you," Holmes answered. "It +is entirely a question of barometric pressure." + +Lestrade looked startled. "I do not quite follow," he said. + +"How is the glass? Twenty-nine, I see. No wind, and not a cloud +in the sky. I have a caseful of cigarettes here which need +smoking, and the sofa is very much superior to the usual country +hotel abomination. I do not think that it is probable that I +shall use the carriage to-night." + +Lestrade laughed indulgently. "You have, no doubt, already formed +your conclusions from the newspapers," he said. "The case is as +plain as a pikestaff, and the more one goes into it the plainer +it becomes. Still, of course, one can't refuse a lady, and such a +very positive one, too. She has heard of you, and would have your +opinion, though I repeatedly told her that there was nothing +which you could do which I had not already done. Why, bless my +soul! here is her carriage at the door." + +He had hardly spoken before there rushed into the room one of the +most lovely young women that I have ever seen in my life. Her +violet eyes shining, her lips parted, a pink flush upon her +cheeks, all thought of her natural reserve lost in her +overpowering excitement and concern. + +"Oh, Mr. Sherlock Holmes!" she cried, glancing from one to the +other of us, and finally, with a woman's quick intuition, +fastening upon my companion, "I am so glad that you have come. I +have driven down to tell you so. I know that James didn't do it. +I know it, and I want you to start upon your work knowing it, +too. Never let yourself doubt upon that point. We have known each +other since we were little children, and I know his faults as no +one else does; but he is too tender-hearted to hurt a fly. Such a +charge is absurd to anyone who really knows him." + +"I hope we may clear him, Miss Turner," said Sherlock Holmes. +"You may rely upon my doing all that I can." + +"But you have read the evidence. You have formed some conclusion? +Do you not see some loophole, some flaw? Do you not yourself +think that he is innocent?" + +"I think that it is very probable." + +"There, now!" she cried, throwing back her head and looking +defiantly at Lestrade. "You hear! He gives me hopes." + +Lestrade shrugged his shoulders. "I am afraid that my colleague +has been a little quick in forming his conclusions," he said. + +"But he is right. Oh! I know that he is right. James never did +it. And about his quarrel with his father, I am sure that the +reason why he would not speak about it to the coroner was because +I was concerned in it." + +"In what way?" asked Holmes. + +"It is no time for me to hide anything. James and his father had +many disagreements about me. Mr. McCarthy was very anxious that +there should be a marriage between us. James and I have always +loved each other as brother and sister; but of course he is young +and has seen very little of life yet, and--and--well, he +naturally did not wish to do anything like that yet. So there +were quarrels, and this, I am sure, was one of them." + +"And your father?" asked Holmes. "Was he in favour of such a +union?" + +"No, he was averse to it also. No one but Mr. McCarthy was in +favour of it." A quick blush passed over her fresh young face as +Holmes shot one of his keen, questioning glances at her. + +"Thank you for this information," said he. "May I see your father +if I call to-morrow?" + +"I am afraid the doctor won't allow it." + +"The doctor?" + +"Yes, have you not heard? Poor father has never been strong for +years back, but this has broken him down completely. He has taken +to his bed, and Dr. Willows says that he is a wreck and that his +nervous system is shattered. Mr. McCarthy was the only man alive +who had known dad in the old days in Victoria." + +"Ha! In Victoria! That is important." + +"Yes, at the mines." + +"Quite so; at the gold-mines, where, as I understand, Mr. Turner +made his money." + +"Yes, certainly." + +"Thank you, Miss Turner. You have been of material assistance to +me." + +"You will tell me if you have any news to-morrow. No doubt you +will go to the prison to see James. Oh, if you do, Mr. Holmes, do +tell him that I know him to be innocent." + +"I will, Miss Turner." + +"I must go home now, for dad is very ill, and he misses me so if +I leave him. Good-bye, and God help you in your undertaking." She +hurried from the room as impulsively as she had entered, and we +heard the wheels of her carriage rattle off down the street. + +"I am ashamed of you, Holmes," said Lestrade with dignity after a +few minutes' silence. "Why should you raise up hopes which you +are bound to disappoint? I am not over-tender of heart, but I +call it cruel." + +"I think that I see my way to clearing James McCarthy," said +Holmes. "Have you an order to see him in prison?" + +"Yes, but only for you and me." + +"Then I shall reconsider my resolution about going out. We have +still time to take a train to Hereford and see him to-night?" + +"Ample." + +"Then let us do so. Watson, I fear that you will find it very +slow, but I shall only be away a couple of hours." + +I walked down to the station with them, and then wandered through +the streets of the little town, finally returning to the hotel, +where I lay upon the sofa and tried to interest myself in a +yellow-backed novel. The puny plot of the story was so thin, +however, when compared to the deep mystery through which we were +groping, and I found my attention wander so continually from the +action to the fact, that I at last flung it across the room and +gave myself up entirely to a consideration of the events of the +day. Supposing that this unhappy young man's story were +absolutely true, then what hellish thing, what absolutely +unforeseen and extraordinary calamity could have occurred between +the time when he parted from his father, and the moment when, +drawn back by his screams, he rushed into the glade? It was +something terrible and deadly. What could it be? Might not the +nature of the injuries reveal something to my medical instincts? +I rang the bell and called for the weekly county paper, which +contained a verbatim account of the inquest. In the surgeon's +deposition it was stated that the posterior third of the left +parietal bone and the left half of the occipital bone had been +shattered by a heavy blow from a blunt weapon. I marked the spot +upon my own head. Clearly such a blow must have been struck from +behind. That was to some extent in favour of the accused, as when +seen quarrelling he was face to face with his father. Still, it +did not go for very much, for the older man might have turned his +back before the blow fell. Still, it might be worth while to call +Holmes' attention to it. Then there was the peculiar dying +reference to a rat. What could that mean? It could not be +delirium. A man dying from a sudden blow does not commonly become +delirious. No, it was more likely to be an attempt to explain how +he met his fate. But what could it indicate? I cudgelled my +brains to find some possible explanation. And then the incident +of the grey cloth seen by young McCarthy. If that were true the +murderer must have dropped some part of his dress, presumably his +overcoat, in his flight, and must have had the hardihood to +return and to carry it away at the instant when the son was +kneeling with his back turned not a dozen paces off. What a +tissue of mysteries and improbabilities the whole thing was! I +did not wonder at Lestrade's opinion, and yet I had so much faith +in Sherlock Holmes' insight that I could not lose hope as long +as every fresh fact seemed to strengthen his conviction of young +McCarthy's innocence. + +It was late before Sherlock Holmes returned. He came back alone, +for Lestrade was staying in lodgings in the town. + +"The glass still keeps very high," he remarked as he sat down. +"It is of importance that it should not rain before we are able +to go over the ground. On the other hand, a man should be at his +very best and keenest for such nice work as that, and I did not +wish to do it when fagged by a long journey. I have seen young +McCarthy." + +"And what did you learn from him?" + +"Nothing." + +"Could he throw no light?" + +"None at all. I was inclined to think at one time that he knew +who had done it and was screening him or her, but I am convinced +now that he is as puzzled as everyone else. He is not a very +quick-witted youth, though comely to look at and, I should think, +sound at heart." + +"I cannot admire his taste," I remarked, "if it is indeed a fact +that he was averse to a marriage with so charming a young lady as +this Miss Turner." + +"Ah, thereby hangs a rather painful tale. This fellow is madly, +insanely, in love with her, but some two years ago, when he was +only a lad, and before he really knew her, for she had been away +five years at a boarding-school, what does the idiot do but get +into the clutches of a barmaid in Bristol and marry her at a +registry office? No one knows a word of the matter, but you can +imagine how maddening it must be to him to be upbraided for not +doing what he would give his very eyes to do, but what he knows +to be absolutely impossible. It was sheer frenzy of this sort +which made him throw his hands up into the air when his father, +at their last interview, was goading him on to propose to Miss +Turner. On the other hand, he had no means of supporting himself, +and his father, who was by all accounts a very hard man, would +have thrown him over utterly had he known the truth. It was with +his barmaid wife that he had spent the last three days in +Bristol, and his father did not know where he was. Mark that +point. It is of importance. Good has come out of evil, however, +for the barmaid, finding from the papers that he is in serious +trouble and likely to be hanged, has thrown him over utterly and +has written to him to say that she has a husband already in the +Bermuda Dockyard, so that there is really no tie between them. I +think that that bit of news has consoled young McCarthy for all +that he has suffered." + +"But if he is innocent, who has done it?" + +"Ah! who? I would call your attention very particularly to two +points. One is that the murdered man had an appointment with +someone at the pool, and that the someone could not have been his +son, for his son was away, and he did not know when he would +return. The second is that the murdered man was heard to cry +'Cooee!' before he knew that his son had returned. Those are the +crucial points upon which the case depends. And now let us talk +about George Meredith, if you please, and we shall leave all +minor matters until to-morrow." + +There was no rain, as Holmes had foretold, and the morning broke +bright and cloudless. At nine o'clock Lestrade called for us with +the carriage, and we set off for Hatherley Farm and the Boscombe +Pool. + +"There is serious news this morning," Lestrade observed. "It is +said that Mr. Turner, of the Hall, is so ill that his life is +despaired of." + +"An elderly man, I presume?" said Holmes. + +"About sixty; but his constitution has been shattered by his life +abroad, and he has been in failing health for some time. This +business has had a very bad effect upon him. He was an old friend +of McCarthy's, and, I may add, a great benefactor to him, for I +have learned that he gave him Hatherley Farm rent free." + +"Indeed! That is interesting," said Holmes. + +"Oh, yes! In a hundred other ways he has helped him. Everybody +about here speaks of his kindness to him." + +"Really! Does it not strike you as a little singular that this +McCarthy, who appears to have had little of his own, and to have +been under such obligations to Turner, should still talk of +marrying his son to Turner's daughter, who is, presumably, +heiress to the estate, and that in such a very cocksure manner, +as if it were merely a case of a proposal and all else would +follow? It is the more strange, since we know that Turner himself +was averse to the idea. The daughter told us as much. Do you not +deduce something from that?" + +"We have got to the deductions and the inferences," said +Lestrade, winking at me. "I find it hard enough to tackle facts, +Holmes, without flying away after theories and fancies." + +"You are right," said Holmes demurely; "you do find it very hard +to tackle the facts." + +"Anyhow, I have grasped one fact which you seem to find it +difficult to get hold of," replied Lestrade with some warmth. + +"And that is--" + +"That McCarthy senior met his death from McCarthy junior and that +all theories to the contrary are the merest moonshine." + +"Well, moonshine is a brighter thing than fog," said Holmes, +laughing. "But I am very much mistaken if this is not Hatherley +Farm upon the left." + +"Yes, that is it." It was a widespread, comfortable-looking +building, two-storied, slate-roofed, with great yellow blotches +of lichen upon the grey walls. The drawn blinds and the smokeless +chimneys, however, gave it a stricken look, as though the weight +of this horror still lay heavy upon it. We called at the door, +when the maid, at Holmes' request, showed us the boots which her +master wore at the time of his death, and also a pair of the +son's, though not the pair which he had then had. Having measured +these very carefully from seven or eight different points, Holmes +desired to be led to the court-yard, from which we all followed +the winding track which led to Boscombe Pool. + +Sherlock Holmes was transformed when he was hot upon such a scent +as this. Men who had only known the quiet thinker and logician of +Baker Street would have failed to recognise him. His face flushed +and darkened. His brows were drawn into two hard black lines, +while his eyes shone out from beneath them with a steely glitter. +His face was bent downward, his shoulders bowed, his lips +compressed, and the veins stood out like whipcord in his long, +sinewy neck. His nostrils seemed to dilate with a purely animal +lust for the chase, and his mind was so absolutely concentrated +upon the matter before him that a question or remark fell +unheeded upon his ears, or, at the most, only provoked a quick, +impatient snarl in reply. Swiftly and silently he made his way +along the track which ran through the meadows, and so by way of +the woods to the Boscombe Pool. It was damp, marshy ground, as is +all that district, and there were marks of many feet, both upon +the path and amid the short grass which bounded it on either +side. Sometimes Holmes would hurry on, sometimes stop dead, and +once he made quite a little detour into the meadow. Lestrade and +I walked behind him, the detective indifferent and contemptuous, +while I watched my friend with the interest which sprang from the +conviction that every one of his actions was directed towards a +definite end. + +The Boscombe Pool, which is a little reed-girt sheet of water +some fifty yards across, is situated at the boundary between the +Hatherley Farm and the private park of the wealthy Mr. Turner. +Above the woods which lined it upon the farther side we could see +the red, jutting pinnacles which marked the site of the rich +landowner's dwelling. On the Hatherley side of the pool the woods +grew very thick, and there was a narrow belt of sodden grass +twenty paces across between the edge of the trees and the reeds +which lined the lake. Lestrade showed us the exact spot at which +the body had been found, and, indeed, so moist was the ground, +that I could plainly see the traces which had been left by the +fall of the stricken man. To Holmes, as I could see by his eager +face and peering eyes, very many other things were to be read +upon the trampled grass. He ran round, like a dog who is picking +up a scent, and then turned upon my companion. + +"What did you go into the pool for?" he asked. + +"I fished about with a rake. I thought there might be some weapon +or other trace. But how on earth--" + +"Oh, tut, tut! I have no time! That left foot of yours with its +inward twist is all over the place. A mole could trace it, and +there it vanishes among the reeds. Oh, how simple it would all +have been had I been here before they came like a herd of buffalo +and wallowed all over it. Here is where the party with the +lodge-keeper came, and they have covered all tracks for six or +eight feet round the body. But here are three separate tracks of +the same feet." He drew out a lens and lay down upon his +waterproof to have a better view, talking all the time rather to +himself than to us. "These are young McCarthy's feet. Twice he +was walking, and once he ran swiftly, so that the soles are +deeply marked and the heels hardly visible. That bears out his +story. He ran when he saw his father on the ground. Then here are +the father's feet as he paced up and down. What is this, then? It +is the butt-end of the gun as the son stood listening. And this? +Ha, ha! What have we here? Tiptoes! tiptoes! Square, too, quite +unusual boots! They come, they go, they come again--of course +that was for the cloak. Now where did they come from?" He ran up +and down, sometimes losing, sometimes finding the track until we +were well within the edge of the wood and under the shadow of a +great beech, the largest tree in the neighbourhood. Holmes traced +his way to the farther side of this and lay down once more upon +his face with a little cry of satisfaction. For a long time he +remained there, turning over the leaves and dried sticks, +gathering up what seemed to me to be dust into an envelope and +examining with his lens not only the ground but even the bark of +the tree as far as he could reach. A jagged stone was lying among +the moss, and this also he carefully examined and retained. Then +he followed a pathway through the wood until he came to the +highroad, where all traces were lost. + +"It has been a case of considerable interest," he remarked, +returning to his natural manner. "I fancy that this grey house on +the right must be the lodge. I think that I will go in and have a +word with Moran, and perhaps write a little note. Having done +that, we may drive back to our luncheon. You may walk to the cab, +and I shall be with you presently." + +It was about ten minutes before we regained our cab and drove +back into Ross, Holmes still carrying with him the stone which he +had picked up in the wood. + +"This may interest you, Lestrade," he remarked, holding it out. +"The murder was done with it." + +"I see no marks." + +"There are none." + +"How do you know, then?" + +"The grass was growing under it. It had only lain there a few +days. There was no sign of a place whence it had been taken. It +corresponds with the injuries. There is no sign of any other +weapon." + +"And the murderer?" + +"Is a tall man, left-handed, limps with the right leg, wears +thick-soled shooting-boots and a grey cloak, smokes Indian +cigars, uses a cigar-holder, and carries a blunt pen-knife in his +pocket. There are several other indications, but these may be +enough to aid us in our search." + +Lestrade laughed. "I am afraid that I am still a sceptic," he +said. "Theories are all very well, but we have to deal with a +hard-headed British jury." + +"Nous verrons," answered Holmes calmly. "You work your own +method, and I shall work mine. I shall be busy this afternoon, +and shall probably return to London by the evening train." + +"And leave your case unfinished?" + +"No, finished." + +"But the mystery?" + +"It is solved." + +"Who was the criminal, then?" + +"The gentleman I describe." + +"But who is he?" + +"Surely it would not be difficult to find out. This is not such a +populous neighbourhood." + +Lestrade shrugged his shoulders. "I am a practical man," he said, +"and I really cannot undertake to go about the country looking +for a left-handed gentleman with a game leg. I should become the +laughing-stock of Scotland Yard." + +"All right," said Holmes quietly. "I have given you the chance. +Here are your lodgings. Good-bye. I shall drop you a line before +I leave." + +Having left Lestrade at his rooms, we drove to our hotel, where +we found lunch upon the table. Holmes was silent and buried in +thought with a pained expression upon his face, as one who finds +himself in a perplexing position. + +"Look here, Watson," he said when the cloth was cleared "just sit +down in this chair and let me preach to you for a little. I don't +know quite what to do, and I should value your advice. Light a +cigar and let me expound." + + "Pray do so." + +"Well, now, in considering this case there are two points about +young McCarthy's narrative which struck us both instantly, +although they impressed me in his favour and you against him. One +was the fact that his father should, according to his account, +cry 'Cooee!' before seeing him. The other was his singular dying +reference to a rat. He mumbled several words, you understand, but +that was all that caught the son's ear. Now from this double +point our research must commence, and we will begin it by +presuming that what the lad says is absolutely true." + +"What of this 'Cooee!' then?" + +"Well, obviously it could not have been meant for the son. The +son, as far as he knew, was in Bristol. It was mere chance that +he was within earshot. The 'Cooee!' was meant to attract the +attention of whoever it was that he had the appointment with. But +'Cooee' is a distinctly Australian cry, and one which is used +between Australians. There is a strong presumption that the +person whom McCarthy expected to meet him at Boscombe Pool was +someone who had been in Australia." + +"What of the rat, then?" + +Sherlock Holmes took a folded paper from his pocket and flattened +it out on the table. "This is a map of the Colony of Victoria," +he said. "I wired to Bristol for it last night." He put his hand +over part of the map. "What do you read?" + +"ARAT," I read. + +"And now?" He raised his hand. + +"BALLARAT." + +"Quite so. That was the word the man uttered, and of which his +son only caught the last two syllables. He was trying to utter +the name of his murderer. So and so, of Ballarat." + +"It is wonderful!" I exclaimed. + +"It is obvious. And now, you see, I had narrowed the field down +considerably. The possession of a grey garment was a third point +which, granting the son's statement to be correct, was a +certainty. We have come now out of mere vagueness to the definite +conception of an Australian from Ballarat with a grey cloak." + +"Certainly." + +"And one who was at home in the district, for the pool can only +be approached by the farm or by the estate, where strangers could +hardly wander." + +"Quite so." + +"Then comes our expedition of to-day. By an examination of the +ground I gained the trifling details which I gave to that +imbecile Lestrade, as to the personality of the criminal." + +"But how did you gain them?" + +"You know my method. It is founded upon the observation of +trifles." + +"His height I know that you might roughly judge from the length +of his stride. His boots, too, might be told from their traces." + +"Yes, they were peculiar boots." + +"But his lameness?" + +"The impression of his right foot was always less distinct than +his left. He put less weight upon it. Why? Because he limped--he +was lame." + +"But his left-handedness." + +"You were yourself struck by the nature of the injury as recorded +by the surgeon at the inquest. The blow was struck from +immediately behind, and yet was upon the left side. Now, how can +that be unless it were by a left-handed man? He had stood behind +that tree during the interview between the father and son. He had +even smoked there. I found the ash of a cigar, which my special +knowledge of tobacco ashes enables me to pronounce as an Indian +cigar. I have, as you know, devoted some attention to this, and +written a little monograph on the ashes of 140 different +varieties of pipe, cigar, and cigarette tobacco. Having found the +ash, I then looked round and discovered the stump among the moss +where he had tossed it. It was an Indian cigar, of the variety +which are rolled in Rotterdam." + +"And the cigar-holder?" + +"I could see that the end had not been in his mouth. Therefore he +used a holder. The tip had been cut off, not bitten off, but the +cut was not a clean one, so I deduced a blunt pen-knife." + +"Holmes," I said, "you have drawn a net round this man from which +he cannot escape, and you have saved an innocent human life as +truly as if you had cut the cord which was hanging him. I see the +direction in which all this points. The culprit is--" + +"Mr. John Turner," cried the hotel waiter, opening the door of +our sitting-room, and ushering in a visitor. + +The man who entered was a strange and impressive figure. His +slow, limping step and bowed shoulders gave the appearance of +decrepitude, and yet his hard, deep-lined, craggy features, and +his enormous limbs showed that he was possessed of unusual +strength of body and of character. His tangled beard, grizzled +hair, and outstanding, drooping eyebrows combined to give an air +of dignity and power to his appearance, but his face was of an +ashen white, while his lips and the corners of his nostrils were +tinged with a shade of blue. It was clear to me at a glance that +he was in the grip of some deadly and chronic disease. + +"Pray sit down on the sofa," said Holmes gently. "You had my +note?" + +"Yes, the lodge-keeper brought it up. You said that you wished to +see me here to avoid scandal." + +"I thought people would talk if I went to the Hall." + +"And why did you wish to see me?" He looked across at my +companion with despair in his weary eyes, as though his question +was already answered. + +"Yes," said Holmes, answering the look rather than the words. "It +is so. I know all about McCarthy." + +The old man sank his face in his hands. "God help me!" he cried. +"But I would not have let the young man come to harm. I give you +my word that I would have spoken out if it went against him at +the Assizes." + +"I am glad to hear you say so," said Holmes gravely. + +"I would have spoken now had it not been for my dear girl. It +would break her heart--it will break her heart when she hears +that I am arrested." + +"It may not come to that," said Holmes. + +"What?" + +"I am no official agent. I understand that it was your daughter +who required my presence here, and I am acting in her interests. +Young McCarthy must be got off, however." + +"I am a dying man," said old Turner. "I have had diabetes for +years. My doctor says it is a question whether I shall live a +month. Yet I would rather die under my own roof than in a gaol." + +Holmes rose and sat down at the table with his pen in his hand +and a bundle of paper before him. "Just tell us the truth," he +said. "I shall jot down the facts. You will sign it, and Watson +here can witness it. Then I could produce your confession at the +last extremity to save young McCarthy. I promise you that I shall +not use it unless it is absolutely needed." + +"It's as well," said the old man; "it's a question whether I +shall live to the Assizes, so it matters little to me, but I +should wish to spare Alice the shock. And now I will make the +thing clear to you; it has been a long time in the acting, but +will not take me long to tell. + +"You didn't know this dead man, McCarthy. He was a devil +incarnate. I tell you that. God keep you out of the clutches of +such a man as he. His grip has been upon me these twenty years, +and he has blasted my life. I'll tell you first how I came to be +in his power. + +"It was in the early '60's at the diggings. I was a young chap +then, hot-blooded and reckless, ready to turn my hand at +anything; I got among bad companions, took to drink, had no luck +with my claim, took to the bush, and in a word became what you +would call over here a highway robber. There were six of us, and +we had a wild, free life of it, sticking up a station from time +to time, or stopping the wagons on the road to the diggings. +Black Jack of Ballarat was the name I went under, and our party +is still remembered in the colony as the Ballarat Gang. + +"One day a gold convoy came down from Ballarat to Melbourne, and +we lay in wait for it and attacked it. There were six troopers +and six of us, so it was a close thing, but we emptied four of +their saddles at the first volley. Three of our boys were killed, +however, before we got the swag. I put my pistol to the head of +the wagon-driver, who was this very man McCarthy. I wish to the +Lord that I had shot him then, but I spared him, though I saw his +wicked little eyes fixed on my face, as though to remember every +feature. We got away with the gold, became wealthy men, and made +our way over to England without being suspected. There I parted +from my old pals and determined to settle down to a quiet and +respectable life. I bought this estate, which chanced to be in +the market, and I set myself to do a little good with my money, +to make up for the way in which I had earned it. I married, too, +and though my wife died young she left me my dear little Alice. +Even when she was just a baby her wee hand seemed to lead me down +the right path as nothing else had ever done. In a word, I turned +over a new leaf and did my best to make up for the past. All was +going well when McCarthy laid his grip upon me. + +"I had gone up to town about an investment, and I met him in +Regent Street with hardly a coat to his back or a boot to his +foot. + +"'Here we are, Jack,' says he, touching me on the arm; 'we'll be +as good as a family to you. There's two of us, me and my son, and +you can have the keeping of us. If you don't--it's a fine, +law-abiding country is England, and there's always a policeman +within hail.' + +"Well, down they came to the west country, there was no shaking +them off, and there they have lived rent free on my best land +ever since. There was no rest for me, no peace, no forgetfulness; +turn where I would, there was his cunning, grinning face at my +elbow. It grew worse as Alice grew up, for he soon saw I was more +afraid of her knowing my past than of the police. Whatever he +wanted he must have, and whatever it was I gave him without +question, land, money, houses, until at last he asked a thing +which I could not give. He asked for Alice. + +"His son, you see, had grown up, and so had my girl, and as I was +known to be in weak health, it seemed a fine stroke to him that +his lad should step into the whole property. But there I was +firm. I would not have his cursed stock mixed with mine; not that +I had any dislike to the lad, but his blood was in him, and that +was enough. I stood firm. McCarthy threatened. I braved him to do +his worst. We were to meet at the pool midway between our houses +to talk it over. + +"When I went down there I found him talking with his son, so I +smoked a cigar and waited behind a tree until he should be alone. +But as I listened to his talk all that was black and bitter in +me seemed to come uppermost. He was urging his son to marry my +daughter with as little regard for what she might think as if she +were a slut from off the streets. It drove me mad to think that I +and all that I held most dear should be in the power of such a +man as this. Could I not snap the bond? I was already a dying and +a desperate man. Though clear of mind and fairly strong of limb, +I knew that my own fate was sealed. But my memory and my girl! +Both could be saved if I could but silence that foul tongue. I +did it, Mr. Holmes. I would do it again. Deeply as I have sinned, +I have led a life of martyrdom to atone for it. But that my girl +should be entangled in the same meshes which held me was more +than I could suffer. I struck him down with no more compunction +than if he had been some foul and venomous beast. His cry brought +back his son; but I had gained the cover of the wood, though I +was forced to go back to fetch the cloak which I had dropped in +my flight. That is the true story, gentlemen, of all that +occurred." + +"Well, it is not for me to judge you," said Holmes as the old man +signed the statement which had been drawn out. "I pray that we +may never be exposed to such a temptation." + +"I pray not, sir. And what do you intend to do?" + +"In view of your health, nothing. You are yourself aware that you +will soon have to answer for your deed at a higher court than the +Assizes. I will keep your confession, and if McCarthy is +condemned I shall be forced to use it. If not, it shall never be +seen by mortal eye; and your secret, whether you be alive or +dead, shall be safe with us." + +"Farewell, then," said the old man solemnly. "Your own deathbeds, +when they come, will be the easier for the thought of the peace +which you have given to mine." Tottering and shaking in all his +giant frame, he stumbled slowly from the room. + +"God help us!" said Holmes after a long silence. "Why does fate +play such tricks with poor, helpless worms? I never hear of such +a case as this that I do not think of Baxter's words, and say, +'There, but for the grace of God, goes Sherlock Holmes.'" + +James McCarthy was acquitted at the Assizes on the strength of a +number of objections which had been drawn out by Holmes and +submitted to the defending counsel. Old Turner lived for seven +months after our interview, but he is now dead; and there is +every prospect that the son and daughter may come to live happily +together in ignorance of the black cloud which rests upon their +past. + + + +ADVENTURE V. THE FIVE ORANGE PIPS + +When I glance over my notes and records of the Sherlock Holmes +cases between the years '82 and '90, I am faced by so many which +present strange and interesting features that it is no easy +matter to know which to choose and which to leave. Some, however, +have already gained publicity through the papers, and others have +not offered a field for those peculiar qualities which my friend +possessed in so high a degree, and which it is the object of +these papers to illustrate. Some, too, have baffled his +analytical skill, and would be, as narratives, beginnings without +an ending, while others have been but partially cleared up, and +have their explanations founded rather upon conjecture and +surmise than on that absolute logical proof which was so dear to +him. There is, however, one of these last which was so remarkable +in its details and so startling in its results that I am tempted +to give some account of it in spite of the fact that there are +points in connection with it which never have been, and probably +never will be, entirely cleared up. + +The year '87 furnished us with a long series of cases of greater +or less interest, of which I retain the records. Among my +headings under this one twelve months I find an account of the +adventure of the Paradol Chamber, of the Amateur Mendicant +Society, who held a luxurious club in the lower vault of a +furniture warehouse, of the facts connected with the loss of the +British barque "Sophy Anderson", of the singular adventures of the +Grice Patersons in the island of Uffa, and finally of the +Camberwell poisoning case. In the latter, as may be remembered, +Sherlock Holmes was able, by winding up the dead man's watch, to +prove that it had been wound up two hours before, and that +therefore the deceased had gone to bed within that time--a +deduction which was of the greatest importance in clearing up the +case. All these I may sketch out at some future date, but none of +them present such singular features as the strange train of +circumstances which I have now taken up my pen to describe. + +It was in the latter days of September, and the equinoctial gales +had set in with exceptional violence. All day the wind had +screamed and the rain had beaten against the windows, so that +even here in the heart of great, hand-made London we were forced +to raise our minds for the instant from the routine of life and +to recognise the presence of those great elemental forces which +shriek at mankind through the bars of his civilisation, like +untamed beasts in a cage. As evening drew in, the storm grew +higher and louder, and the wind cried and sobbed like a child in +the chimney. Sherlock Holmes sat moodily at one side of the +fireplace cross-indexing his records of crime, while I at the +other was deep in one of Clark Russell's fine sea-stories until +the howl of the gale from without seemed to blend with the text, +and the splash of the rain to lengthen out into the long swash of +the sea waves. My wife was on a visit to her mother's, and for a +few days I was a dweller once more in my old quarters at Baker +Street. + +"Why," said I, glancing up at my companion, "that was surely the +bell. Who could come to-night? Some friend of yours, perhaps?" + +"Except yourself I have none," he answered. "I do not encourage +visitors." + +"A client, then?" + +"If so, it is a serious case. Nothing less would bring a man out +on such a day and at such an hour. But I take it that it is more +likely to be some crony of the landlady's." + +Sherlock Holmes was wrong in his conjecture, however, for there +came a step in the passage and a tapping at the door. He +stretched out his long arm to turn the lamp away from himself and +towards the vacant chair upon which a newcomer must sit. + +"Come in!" said he. + +The man who entered was young, some two-and-twenty at the +outside, well-groomed and trimly clad, with something of +refinement and delicacy in his bearing. The streaming umbrella +which he held in his hand, and his long shining waterproof told +of the fierce weather through which he had come. He looked about +him anxiously in the glare of the lamp, and I could see that his +face was pale and his eyes heavy, like those of a man who is +weighed down with some great anxiety. + +"I owe you an apology," he said, raising his golden pince-nez to +his eyes. "I trust that I am not intruding. I fear that I have +brought some traces of the storm and rain into your snug +chamber." + +"Give me your coat and umbrella," said Holmes. "They may rest +here on the hook and will be dry presently. You have come up from +the south-west, I see." + +"Yes, from Horsham." + +"That clay and chalk mixture which I see upon your toe caps is +quite distinctive." + +"I have come for advice." + +"That is easily got." + +"And help." + +"That is not always so easy." + +"I have heard of you, Mr. Holmes. I heard from Major Prendergast +how you saved him in the Tankerville Club scandal." + +"Ah, of course. He was wrongfully accused of cheating at cards." + +"He said that you could solve anything." + +"He said too much." + +"That you are never beaten." + +"I have been beaten four times--three times by men, and once by a +woman." + +"But what is that compared with the number of your successes?" + +"It is true that I have been generally successful." + +"Then you may be so with me." + +"I beg that you will draw your chair up to the fire and favour me +with some details as to your case." + +"It is no ordinary one." + +"None of those which come to me are. I am the last court of +appeal." + +"And yet I question, sir, whether, in all your experience, you +have ever listened to a more mysterious and inexplicable chain of +events than those which have happened in my own family." + +"You fill me with interest," said Holmes. "Pray give us the +essential facts from the commencement, and I can afterwards +question you as to those details which seem to me to be most +important." + +The young man pulled his chair up and pushed his wet feet out +towards the blaze. + +"My name," said he, "is John Openshaw, but my own affairs have, +as far as I can understand, little to do with this awful +business. It is a hereditary matter; so in order to give you an +idea of the facts, I must go back to the commencement of the +affair. + +"You must know that my grandfather had two sons--my uncle Elias +and my father Joseph. My father had a small factory at Coventry, +which he enlarged at the time of the invention of bicycling. He +was a patentee of the Openshaw unbreakable tire, and his business +met with such success that he was able to sell it and to retire +upon a handsome competence. + +"My uncle Elias emigrated to America when he was a young man and +became a planter in Florida, where he was reported to have done +very well. At the time of the war he fought in Jackson's army, +and afterwards under Hood, where he rose to be a colonel. When +Lee laid down his arms my uncle returned to his plantation, where +he remained for three or four years. About 1869 or 1870 he came +back to Europe and took a small estate in Sussex, near Horsham. +He had made a very considerable fortune in the States, and his +reason for leaving them was his aversion to the negroes, and his +dislike of the Republican policy in extending the franchise to +them. He was a singular man, fierce and quick-tempered, very +foul-mouthed when he was angry, and of a most retiring +disposition. During all the years that he lived at Horsham, I +doubt if ever he set foot in the town. He had a garden and two or +three fields round his house, and there he would take his +exercise, though very often for weeks on end he would never leave +his room. He drank a great deal of brandy and smoked very +heavily, but he would see no society and did not want any +friends, not even his own brother. + +"He didn't mind me; in fact, he took a fancy to me, for at the +time when he saw me first I was a youngster of twelve or so. This +would be in the year 1878, after he had been eight or nine years +in England. He begged my father to let me live with him and he +was very kind to me in his way. When he was sober he used to be +fond of playing backgammon and draughts with me, and he would +make me his representative both with the servants and with the +tradespeople, so that by the time that I was sixteen I was quite +master of the house. I kept all the keys and could go where I +liked and do what I liked, so long as I did not disturb him in +his privacy. There was one singular exception, however, for he +had a single room, a lumber-room up among the attics, which was +invariably locked, and which he would never permit either me or +anyone else to enter. With a boy's curiosity I have peeped +through the keyhole, but I was never able to see more than such a +collection of old trunks and bundles as would be expected in such +a room. + +"One day--it was in March, 1883--a letter with a foreign stamp +lay upon the table in front of the colonel's plate. It was not a +common thing for him to receive letters, for his bills were all +paid in ready money, and he had no friends of any sort. 'From +India!' said he as he took it up, 'Pondicherry postmark! What can +this be?' Opening it hurriedly, out there jumped five little +dried orange pips, which pattered down upon his plate. I began to +laugh at this, but the laugh was struck from my lips at the sight +of his face. His lip had fallen, his eyes were protruding, his +skin the colour of putty, and he glared at the envelope which he +still held in his trembling hand, 'K. K. K.!' he shrieked, and +then, 'My God, my God, my sins have overtaken me!' + +"'What is it, uncle?' I cried. + +"'Death,' said he, and rising from the table he retired to his +room, leaving me palpitating with horror. I took up the envelope +and saw scrawled in red ink upon the inner flap, just above the +gum, the letter K three times repeated. There was nothing else +save the five dried pips. What could be the reason of his +overpowering terror? I left the breakfast-table, and as I +ascended the stair I met him coming down with an old rusty key, +which must have belonged to the attic, in one hand, and a small +brass box, like a cashbox, in the other. + +"'They may do what they like, but I'll checkmate them still,' +said he with an oath. 'Tell Mary that I shall want a fire in my +room to-day, and send down to Fordham, the Horsham lawyer.' + +"I did as he ordered, and when the lawyer arrived I was asked to +step up to the room. The fire was burning brightly, and in the +grate there was a mass of black, fluffy ashes, as of burned +paper, while the brass box stood open and empty beside it. As I +glanced at the box I noticed, with a start, that upon the lid was +printed the treble K which I had read in the morning upon the +envelope. + +"'I wish you, John,' said my uncle, 'to witness my will. I leave +my estate, with all its advantages and all its disadvantages, to +my brother, your father, whence it will, no doubt, descend to +you. If you can enjoy it in peace, well and good! If you find you +cannot, take my advice, my boy, and leave it to your deadliest +enemy. I am sorry to give you such a two-edged thing, but I can't +say what turn things are going to take. Kindly sign the paper +where Mr. Fordham shows you.' + +"I signed the paper as directed, and the lawyer took it away with +him. The singular incident made, as you may think, the deepest +impression upon me, and I pondered over it and turned it every +way in my mind without being able to make anything of it. Yet I +could not shake off the vague feeling of dread which it left +behind, though the sensation grew less keen as the weeks passed +and nothing happened to disturb the usual routine of our lives. I +could see a change in my uncle, however. He drank more than ever, +and he was less inclined for any sort of society. Most of his +time he would spend in his room, with the door locked upon the +inside, but sometimes he would emerge in a sort of drunken frenzy +and would burst out of the house and tear about the garden with a +revolver in his hand, screaming out that he was afraid of no man, +and that he was not to be cooped up, like a sheep in a pen, by +man or devil. When these hot fits were over, however, he would +rush tumultuously in at the door and lock and bar it behind him, +like a man who can brazen it out no longer against the terror +which lies at the roots of his soul. At such times I have seen +his face, even on a cold day, glisten with moisture, as though it +were new raised from a basin. + +"Well, to come to an end of the matter, Mr. Holmes, and not to +abuse your patience, there came a night when he made one of those +drunken sallies from which he never came back. We found him, when +we went to search for him, face downward in a little +green-scummed pool, which lay at the foot of the garden. There +was no sign of any violence, and the water was but two feet deep, +so that the jury, having regard to his known eccentricity, +brought in a verdict of 'suicide.' But I, who knew how he winced +from the very thought of death, had much ado to persuade myself +that he had gone out of his way to meet it. The matter passed, +however, and my father entered into possession of the estate, and +of some 14,000 pounds, which lay to his credit at the bank." + +"One moment," Holmes interposed, "your statement is, I foresee, +one of the most remarkable to which I have ever listened. Let me +have the date of the reception by your uncle of the letter, and +the date of his supposed suicide." + +"The letter arrived on March 10, 1883. His death was seven weeks +later, upon the night of May 2nd." + +"Thank you. Pray proceed." + +"When my father took over the Horsham property, he, at my +request, made a careful examination of the attic, which had been +always locked up. We found the brass box there, although its +contents had been destroyed. On the inside of the cover was a +paper label, with the initials of K. K. K. repeated upon it, and +'Letters, memoranda, receipts, and a register' written beneath. +These, we presume, indicated the nature of the papers which had +been destroyed by Colonel Openshaw. For the rest, there was +nothing of much importance in the attic save a great many +scattered papers and note-books bearing upon my uncle's life in +America. Some of them were of the war time and showed that he had +done his duty well and had borne the repute of a brave soldier. +Others were of a date during the reconstruction of the Southern +states, and were mostly concerned with politics, for he had +evidently taken a strong part in opposing the carpet-bag +politicians who had been sent down from the North. + +"Well, it was the beginning of '84 when my father came to live at +Horsham, and all went as well as possible with us until the +January of '85. On the fourth day after the new year I heard my +father give a sharp cry of surprise as we sat together at the +breakfast-table. There he was, sitting with a newly opened +envelope in one hand and five dried orange pips in the +outstretched palm of the other one. He had always laughed at what +he called my cock-and-bull story about the colonel, but he looked +very scared and puzzled now that the same thing had come upon +himself. + +"'Why, what on earth does this mean, John?' he stammered. + +"My heart had turned to lead. 'It is K. K. K.,' said I. + +"He looked inside the envelope. 'So it is,' he cried. 'Here are +the very letters. But what is this written above them?' + +"'Put the papers on the sundial,' I read, peeping over his +shoulder. + +"'What papers? What sundial?' he asked. + +"'The sundial in the garden. There is no other,' said I; 'but the +papers must be those that are destroyed.' + +"'Pooh!' said he, gripping hard at his courage. 'We are in a +civilised land here, and we can't have tomfoolery of this kind. +Where does the thing come from?' + +"'From Dundee,' I answered, glancing at the postmark. + +"'Some preposterous practical joke,' said he. 'What have I to do +with sundials and papers? I shall take no notice of such +nonsense.' + +"'I should certainly speak to the police,' I said. + +"'And be laughed at for my pains. Nothing of the sort.' + +"'Then let me do so?' + +"'No, I forbid you. I won't have a fuss made about such +nonsense.' + +"It was in vain to argue with him, for he was a very obstinate +man. I went about, however, with a heart which was full of +forebodings. + +"On the third day after the coming of the letter my father went +from home to visit an old friend of his, Major Freebody, who is +in command of one of the forts upon Portsdown Hill. I was glad +that he should go, for it seemed to me that he was farther from +danger when he was away from home. In that, however, I was in +error. Upon the second day of his absence I received a telegram +from the major, imploring me to come at once. My father had +fallen over one of the deep chalk-pits which abound in the +neighbourhood, and was lying senseless, with a shattered skull. I +hurried to him, but he passed away without having ever recovered +his consciousness. He had, as it appears, been returning from +Fareham in the twilight, and as the country was unknown to him, +and the chalk-pit unfenced, the jury had no hesitation in +bringing in a verdict of 'death from accidental causes.' +Carefully as I examined every fact connected with his death, I +was unable to find anything which could suggest the idea of +murder. There were no signs of violence, no footmarks, no +robbery, no record of strangers having been seen upon the roads. +And yet I need not tell you that my mind was far from at ease, +and that I was well-nigh certain that some foul plot had been +woven round him. + +"In this sinister way I came into my inheritance. You will ask me +why I did not dispose of it? I answer, because I was well +convinced that our troubles were in some way dependent upon an +incident in my uncle's life, and that the danger would be as +pressing in one house as in another. + +"It was in January, '85, that my poor father met his end, and two +years and eight months have elapsed since then. During that time +I have lived happily at Horsham, and I had begun to hope that +this curse had passed away from the family, and that it had ended +with the last generation. I had begun to take comfort too soon, +however; yesterday morning the blow fell in the very shape in +which it had come upon my father." + +The young man took from his waistcoat a crumpled envelope, and +turning to the table he shook out upon it five little dried +orange pips. + +"This is the envelope," he continued. "The postmark is +London--eastern division. Within are the very words which were +upon my father's last message: 'K. K. K.'; and then 'Put the +papers on the sundial.'" + +"What have you done?" asked Holmes. + +"Nothing." + +"Nothing?" + +"To tell the truth"--he sank his face into his thin, white +hands--"I have felt helpless. I have felt like one of those poor +rabbits when the snake is writhing towards it. I seem to be in +the grasp of some resistless, inexorable evil, which no foresight +and no precautions can guard against." + +"Tut! tut!" cried Sherlock Holmes. "You must act, man, or you are +lost. Nothing but energy can save you. This is no time for +despair." + +"I have seen the police." + +"Ah!" + +"But they listened to my story with a smile. I am convinced that +the inspector has formed the opinion that the letters are all +practical jokes, and that the deaths of my relations were really +accidents, as the jury stated, and were not to be connected with +the warnings." + +Holmes shook his clenched hands in the air. "Incredible +imbecility!" he cried. + +"They have, however, allowed me a policeman, who may remain in +the house with me." + +"Has he come with you to-night?" + +"No. His orders were to stay in the house." + +Again Holmes raved in the air. + +"Why did you come to me," he cried, "and, above all, why did you +not come at once?" + +"I did not know. It was only to-day that I spoke to Major +Prendergast about my troubles and was advised by him to come to +you." + +"It is really two days since you had the letter. We should have +acted before this. You have no further evidence, I suppose, than +that which you have placed before us--no suggestive detail which +might help us?" + +"There is one thing," said John Openshaw. He rummaged in his coat +pocket, and, drawing out a piece of discoloured, blue-tinted +paper, he laid it out upon the table. "I have some remembrance," +said he, "that on the day when my uncle burned the papers I +observed that the small, unburned margins which lay amid the +ashes were of this particular colour. I found this single sheet +upon the floor of his room, and I am inclined to think that it +may be one of the papers which has, perhaps, fluttered out from +among the others, and in that way has escaped destruction. Beyond +the mention of pips, I do not see that it helps us much. I think +myself that it is a page from some private diary. The writing is +undoubtedly my uncle's." + +Holmes moved the lamp, and we both bent over the sheet of paper, +which showed by its ragged edge that it had indeed been torn from +a book. It was headed, "March, 1869," and beneath were the +following enigmatical notices: + +"4th. Hudson came. Same old platform. + +"7th. Set the pips on McCauley, Paramore, and + John Swain, of St. Augustine. + +"9th. McCauley cleared. + +"10th. John Swain cleared. + +"12th. Visited Paramore. All well." + +"Thank you!" said Holmes, folding up the paper and returning it +to our visitor. "And now you must on no account lose another +instant. We cannot spare time even to discuss what you have told +me. You must get home instantly and act." + +"What shall I do?" + +"There is but one thing to do. It must be done at once. You must +put this piece of paper which you have shown us into the brass +box which you have described. You must also put in a note to say +that all the other papers were burned by your uncle, and that +this is the only one which remains. You must assert that in such +words as will carry conviction with them. Having done this, you +must at once put the box out upon the sundial, as directed. Do +you understand?" + +"Entirely." + +"Do not think of revenge, or anything of the sort, at present. I +think that we may gain that by means of the law; but we have our +web to weave, while theirs is already woven. The first +consideration is to remove the pressing danger which threatens +you. The second is to clear up the mystery and to punish the +guilty parties." + +"I thank you," said the young man, rising and pulling on his +overcoat. "You have given me fresh life and hope. I shall +certainly do as you advise." + +"Do not lose an instant. And, above all, take care of yourself in +the meanwhile, for I do not think that there can be a doubt that +you are threatened by a very real and imminent danger. How do you +go back?" + +"By train from Waterloo." + +"It is not yet nine. The streets will be crowded, so I trust that +you may be in safety. And yet you cannot guard yourself too +closely." + +"I am armed." + +"That is well. To-morrow I shall set to work upon your case." + +"I shall see you at Horsham, then?" + +"No, your secret lies in London. It is there that I shall seek +it." + +"Then I shall call upon you in a day, or in two days, with news +as to the box and the papers. I shall take your advice in every +particular." He shook hands with us and took his leave. Outside +the wind still screamed and the rain splashed and pattered +against the windows. This strange, wild story seemed to have come +to us from amid the mad elements--blown in upon us like a sheet +of sea-weed in a gale--and now to have been reabsorbed by them +once more. + +Sherlock Holmes sat for some time in silence, with his head sunk +forward and his eyes bent upon the red glow of the fire. Then he +lit his pipe, and leaning back in his chair he watched the blue +smoke-rings as they chased each other up to the ceiling. + +"I think, Watson," he remarked at last, "that of all our cases we +have had none more fantastic than this." + +"Save, perhaps, the Sign of Four." + +"Well, yes. Save, perhaps, that. And yet this John Openshaw seems +to me to be walking amid even greater perils than did the +Sholtos." + +"But have you," I asked, "formed any definite conception as to +what these perils are?" + +"There can be no question as to their nature," he answered. + +"Then what are they? Who is this K. K. K., and why does he pursue +this unhappy family?" + +Sherlock Holmes closed his eyes and placed his elbows upon the +arms of his chair, with his finger-tips together. "The ideal +reasoner," he remarked, "would, when he had once been shown a +single fact in all its bearings, deduce from it not only all the +chain of events which led up to it but also all the results which +would follow from it. As Cuvier could correctly describe a whole +animal by the contemplation of a single bone, so the observer who +has thoroughly understood one link in a series of incidents +should be able to accurately state all the other ones, both +before and after. We have not yet grasped the results which the +reason alone can attain to. Problems may be solved in the study +which have baffled all those who have sought a solution by the +aid of their senses. To carry the art, however, to its highest +pitch, it is necessary that the reasoner should be able to +utilise all the facts which have come to his knowledge; and this +in itself implies, as you will readily see, a possession of all +knowledge, which, even in these days of free education and +encyclopaedias, is a somewhat rare accomplishment. It is not so +impossible, however, that a man should possess all knowledge +which is likely to be useful to him in his work, and this I have +endeavoured in my case to do. If I remember rightly, you on one +occasion, in the early days of our friendship, defined my limits +in a very precise fashion." + +"Yes," I answered, laughing. "It was a singular document. +Philosophy, astronomy, and politics were marked at zero, I +remember. Botany variable, geology profound as regards the +mud-stains from any region within fifty miles of town, chemistry +eccentric, anatomy unsystematic, sensational literature and crime +records unique, violin-player, boxer, swordsman, lawyer, and +self-poisoner by cocaine and tobacco. Those, I think, were the +main points of my analysis." + +Holmes grinned at the last item. "Well," he said, "I say now, as +I said then, that a man should keep his little brain-attic +stocked with all the furniture that he is likely to use, and the +rest he can put away in the lumber-room of his library, where he +can get it if he wants it. Now, for such a case as the one which +has been submitted to us to-night, we need certainly to muster +all our resources. Kindly hand me down the letter K of the +'American Encyclopaedia' which stands upon the shelf beside you. +Thank you. Now let us consider the situation and see what may be +deduced from it. In the first place, we may start with a strong +presumption that Colonel Openshaw had some very strong reason for +leaving America. Men at his time of life do not change all their +habits and exchange willingly the charming climate of Florida for +the lonely life of an English provincial town. His extreme love +of solitude in England suggests the idea that he was in fear of +someone or something, so we may assume as a working hypothesis +that it was fear of someone or something which drove him from +America. As to what it was he feared, we can only deduce that by +considering the formidable letters which were received by himself +and his successors. Did you remark the postmarks of those +letters?" + +"The first was from Pondicherry, the second from Dundee, and the +third from London." + +"From East London. What do you deduce from that?" + +"They are all seaports. That the writer was on board of a ship." + +"Excellent. We have already a clue. There can be no doubt that +the probability--the strong probability--is that the writer was +on board of a ship. And now let us consider another point. In the +case of Pondicherry, seven weeks elapsed between the threat and +its fulfilment, in Dundee it was only some three or four days. +Does that suggest anything?" + +"A greater distance to travel." + +"But the letter had also a greater distance to come." + +"Then I do not see the point." + +"There is at least a presumption that the vessel in which the man +or men are is a sailing-ship. It looks as if they always send +their singular warning or token before them when starting upon +their mission. You see how quickly the deed followed the sign +when it came from Dundee. If they had come from Pondicherry in a +steamer they would have arrived almost as soon as their letter. +But, as a matter of fact, seven weeks elapsed. I think that those +seven weeks represented the difference between the mail-boat which +brought the letter and the sailing vessel which brought the +writer." + +"It is possible." + +"More than that. It is probable. And now you see the deadly +urgency of this new case, and why I urged young Openshaw to +caution. The blow has always fallen at the end of the time which +it would take the senders to travel the distance. But this one +comes from London, and therefore we cannot count upon delay." + +"Good God!" I cried. "What can it mean, this relentless +persecution?" + +"The papers which Openshaw carried are obviously of vital +importance to the person or persons in the sailing-ship. I think +that it is quite clear that there must be more than one of them. +A single man could not have carried out two deaths in such a way +as to deceive a coroner's jury. There must have been several in +it, and they must have been men of resource and determination. +Their papers they mean to have, be the holder of them who it may. +In this way you see K. K. K. ceases to be the initials of an +individual and becomes the badge of a society." + +"But of what society?" + +"Have you never--" said Sherlock Holmes, bending forward and +sinking his voice--"have you never heard of the Ku Klux Klan?" + +"I never have." + +Holmes turned over the leaves of the book upon his knee. "Here it +is," said he presently: + +"'Ku Klux Klan. A name derived from the fanciful resemblance to +the sound produced by cocking a rifle. This terrible secret +society was formed by some ex-Confederate soldiers in the +Southern states after the Civil War, and it rapidly formed local +branches in different parts of the country, notably in Tennessee, +Louisiana, the Carolinas, Georgia, and Florida. Its power was +used for political purposes, principally for the terrorising of +the negro voters and the murdering and driving from the country +of those who were opposed to its views. Its outrages were usually +preceded by a warning sent to the marked man in some fantastic +but generally recognised shape--a sprig of oak-leaves in some +parts, melon seeds or orange pips in others. On receiving this +the victim might either openly abjure his former ways, or might +fly from the country. If he braved the matter out, death would +unfailingly come upon him, and usually in some strange and +unforeseen manner. So perfect was the organisation of the +society, and so systematic its methods, that there is hardly a +case upon record where any man succeeded in braving it with +impunity, or in which any of its outrages were traced home to the +perpetrators. For some years the organisation flourished in spite +of the efforts of the United States government and of the better +classes of the community in the South. Eventually, in the year +1869, the movement rather suddenly collapsed, although there have +been sporadic outbreaks of the same sort since that date.' + +"You will observe," said Holmes, laying down the volume, "that +the sudden breaking up of the society was coincident with the +disappearance of Openshaw from America with their papers. It may +well have been cause and effect. It is no wonder that he and his +family have some of the more implacable spirits upon their track. +You can understand that this register and diary may implicate +some of the first men in the South, and that there may be many +who will not sleep easy at night until it is recovered." + +"Then the page we have seen--" + +"Is such as we might expect. It ran, if I remember right, 'sent +the pips to A, B, and C'--that is, sent the society's warning to +them. Then there are successive entries that A and B cleared, or +left the country, and finally that C was visited, with, I fear, a +sinister result for C. Well, I think, Doctor, that we may let +some light into this dark place, and I believe that the only +chance young Openshaw has in the meantime is to do what I have +told him. There is nothing more to be said or to be done +to-night, so hand me over my violin and let us try to forget for +half an hour the miserable weather and the still more miserable +ways of our fellow-men." + + +It had cleared in the morning, and the sun was shining with a +subdued brightness through the dim veil which hangs over the +great city. Sherlock Holmes was already at breakfast when I came +down. + +"You will excuse me for not waiting for you," said he; "I have, I +foresee, a very busy day before me in looking into this case of +young Openshaw's." + +"What steps will you take?" I asked. + +"It will very much depend upon the results of my first inquiries. +I may have to go down to Horsham, after all." + +"You will not go there first?" + +"No, I shall commence with the City. Just ring the bell and the +maid will bring up your coffee." + +As I waited, I lifted the unopened newspaper from the table and +glanced my eye over it. It rested upon a heading which sent a +chill to my heart. + +"Holmes," I cried, "you are too late." + +"Ah!" said he, laying down his cup, "I feared as much. How was it +done?" He spoke calmly, but I could see that he was deeply moved. + +"My eye caught the name of Openshaw, and the heading 'Tragedy +Near Waterloo Bridge.' Here is the account: + +"Between nine and ten last night Police-Constable Cook, of the H +Division, on duty near Waterloo Bridge, heard a cry for help and +a splash in the water. The night, however, was extremely dark and +stormy, so that, in spite of the help of several passers-by, it +was quite impossible to effect a rescue. The alarm, however, was +given, and, by the aid of the water-police, the body was +eventually recovered. It proved to be that of a young gentleman +whose name, as it appears from an envelope which was found in his +pocket, was John Openshaw, and whose residence is near Horsham. +It is conjectured that he may have been hurrying down to catch +the last train from Waterloo Station, and that in his haste and +the extreme darkness he missed his path and walked over the edge +of one of the small landing-places for river steamboats. The body +exhibited no traces of violence, and there can be no doubt that +the deceased had been the victim of an unfortunate accident, +which should have the effect of calling the attention of the +authorities to the condition of the riverside landing-stages." + +We sat in silence for some minutes, Holmes more depressed and +shaken than I had ever seen him. + +"That hurts my pride, Watson," he said at last. "It is a petty +feeling, no doubt, but it hurts my pride. It becomes a personal +matter with me now, and, if God sends me health, I shall set my +hand upon this gang. That he should come to me for help, and that +I should send him away to his death--!" He sprang from his chair +and paced about the room in uncontrollable agitation, with a +flush upon his sallow cheeks and a nervous clasping and +unclasping of his long thin hands. + +"They must be cunning devils," he exclaimed at last. "How could +they have decoyed him down there? The Embankment is not on the +direct line to the station. The bridge, no doubt, was too +crowded, even on such a night, for their purpose. Well, Watson, +we shall see who will win in the long run. I am going out now!" + +"To the police?" + +"No; I shall be my own police. When I have spun the web they may +take the flies, but not before." + +All day I was engaged in my professional work, and it was late in +the evening before I returned to Baker Street. Sherlock Holmes +had not come back yet. It was nearly ten o'clock before he +entered, looking pale and worn. He walked up to the sideboard, +and tearing a piece from the loaf he devoured it voraciously, +washing it down with a long draught of water. + +"You are hungry," I remarked. + +"Starving. It had escaped my memory. I have had nothing since +breakfast." + +"Nothing?" + +"Not a bite. I had no time to think of it." + +"And how have you succeeded?" + +"Well." + +"You have a clue?" + +"I have them in the hollow of my hand. Young Openshaw shall not +long remain unavenged. Why, Watson, let us put their own devilish +trade-mark upon them. It is well thought of!" + +"What do you mean?" + +He took an orange from the cupboard, and tearing it to pieces he +squeezed out the pips upon the table. Of these he took five and +thrust them into an envelope. On the inside of the flap he wrote +"S. H. for J. O." Then he sealed it and addressed it to "Captain +James Calhoun, Barque 'Lone Star,' Savannah, Georgia." + +"That will await him when he enters port," said he, chuckling. +"It may give him a sleepless night. He will find it as sure a +precursor of his fate as Openshaw did before him." + +"And who is this Captain Calhoun?" + +"The leader of the gang. I shall have the others, but he first." + +"How did you trace it, then?" + +He took a large sheet of paper from his pocket, all covered with +dates and names. + +"I have spent the whole day," said he, "over Lloyd's registers +and files of the old papers, following the future career of every +vessel which touched at Pondicherry in January and February in +'83. There were thirty-six ships of fair tonnage which were +reported there during those months. Of these, one, the 'Lone Star,' +instantly attracted my attention, since, although it was reported +as having cleared from London, the name is that which is given to +one of the states of the Union." + +"Texas, I think." + +"I was not and am not sure which; but I knew that the ship must +have an American origin." + +"What then?" + +"I searched the Dundee records, and when I found that the barque +'Lone Star' was there in January, '85, my suspicion became a +certainty. I then inquired as to the vessels which lay at present +in the port of London." + +"Yes?" + +"The 'Lone Star' had arrived here last week. I went down to the +Albert Dock and found that she had been taken down the river by +the early tide this morning, homeward bound to Savannah. I wired +to Gravesend and learned that she had passed some time ago, and +as the wind is easterly I have no doubt that she is now past the +Goodwins and not very far from the Isle of Wight." + +"What will you do, then?" + +"Oh, I have my hand upon him. He and the two mates, are as I +learn, the only native-born Americans in the ship. The others are +Finns and Germans. I know, also, that they were all three away +from the ship last night. I had it from the stevedore who has +been loading their cargo. By the time that their sailing-ship +reaches Savannah the mail-boat will have carried this letter, and +the cable will have informed the police of Savannah that these +three gentlemen are badly wanted here upon a charge of murder." + +There is ever a flaw, however, in the best laid of human plans, +and the murderers of John Openshaw were never to receive the +orange pips which would show them that another, as cunning and as +resolute as themselves, was upon their track. Very long and very +severe were the equinoctial gales that year. We waited long for +news of the "Lone Star" of Savannah, but none ever reached us. We +did at last hear that somewhere far out in the Atlantic a +shattered stern-post of a boat was seen swinging in the trough +of a wave, with the letters "L. S." carved upon it, and that is +all which we shall ever know of the fate of the "Lone Star." + + + +ADVENTURE VI. THE MAN WITH THE TWISTED LIP + +Isa Whitney, brother of the late Elias Whitney, D.D., Principal +of the Theological College of St. George's, was much addicted to +opium. The habit grew upon him, as I understand, from some +foolish freak when he was at college; for having read De +Quincey's description of his dreams and sensations, he had +drenched his tobacco with laudanum in an attempt to produce the +same effects. He found, as so many more have done, that the +practice is easier to attain than to get rid of, and for many +years he continued to be a slave to the drug, an object of +mingled horror and pity to his friends and relatives. I can see +him now, with yellow, pasty face, drooping lids, and pin-point +pupils, all huddled in a chair, the wreck and ruin of a noble +man. + +One night--it was in June, '89--there came a ring to my bell, +about the hour when a man gives his first yawn and glances at the +clock. I sat up in my chair, and my wife laid her needle-work +down in her lap and made a little face of disappointment. + +"A patient!" said she. "You'll have to go out." + +I groaned, for I was newly come back from a weary day. + +We heard the door open, a few hurried words, and then quick steps +upon the linoleum. Our own door flew open, and a lady, clad in +some dark-coloured stuff, with a black veil, entered the room. + +"You will excuse my calling so late," she began, and then, +suddenly losing her self-control, she ran forward, threw her arms +about my wife's neck, and sobbed upon her shoulder. "Oh, I'm in +such trouble!" she cried; "I do so want a little help." + +"Why," said my wife, pulling up her veil, "it is Kate Whitney. +How you startled me, Kate! I had not an idea who you were when +you came in." + +"I didn't know what to do, so I came straight to you." That was +always the way. Folk who were in grief came to my wife like birds +to a light-house. + +"It was very sweet of you to come. Now, you must have some wine +and water, and sit here comfortably and tell us all about it. Or +should you rather that I sent James off to bed?" + +"Oh, no, no! I want the doctor's advice and help, too. It's about +Isa. He has not been home for two days. I am so frightened about +him!" + +It was not the first time that she had spoken to us of her +husband's trouble, to me as a doctor, to my wife as an old friend +and school companion. We soothed and comforted her by such words +as we could find. Did she know where her husband was? Was it +possible that we could bring him back to her? + +It seems that it was. She had the surest information that of late +he had, when the fit was on him, made use of an opium den in the +farthest east of the City. Hitherto his orgies had always been +confined to one day, and he had come back, twitching and +shattered, in the evening. But now the spell had been upon him +eight-and-forty hours, and he lay there, doubtless among the +dregs of the docks, breathing in the poison or sleeping off the +effects. There he was to be found, she was sure of it, at the Bar +of Gold, in Upper Swandam Lane. But what was she to do? How could +she, a young and timid woman, make her way into such a place and +pluck her husband out from among the ruffians who surrounded him? + +There was the case, and of course there was but one way out of +it. Might I not escort her to this place? And then, as a second +thought, why should she come at all? I was Isa Whitney's medical +adviser, and as such I had influence over him. I could manage it +better if I were alone. I promised her on my word that I would +send him home in a cab within two hours if he were indeed at the +address which she had given me. And so in ten minutes I had left +my armchair and cheery sitting-room behind me, and was speeding +eastward in a hansom on a strange errand, as it seemed to me at +the time, though the future only could show how strange it was to +be. + +But there was no great difficulty in the first stage of my +adventure. Upper Swandam Lane is a vile alley lurking behind the +high wharves which line the north side of the river to the east +of London Bridge. Between a slop-shop and a gin-shop, approached +by a steep flight of steps leading down to a black gap like the +mouth of a cave, I found the den of which I was in search. +Ordering my cab to wait, I passed down the steps, worn hollow in +the centre by the ceaseless tread of drunken feet; and by the +light of a flickering oil-lamp above the door I found the latch +and made my way into a long, low room, thick and heavy with the +brown opium smoke, and terraced with wooden berths, like the +forecastle of an emigrant ship. + +Through the gloom one could dimly catch a glimpse of bodies lying +in strange fantastic poses, bowed shoulders, bent knees, heads +thrown back, and chins pointing upward, with here and there a +dark, lack-lustre eye turned upon the newcomer. Out of the black +shadows there glimmered little red circles of light, now bright, +now faint, as the burning poison waxed or waned in the bowls of +the metal pipes. The most lay silent, but some muttered to +themselves, and others talked together in a strange, low, +monotonous voice, their conversation coming in gushes, and then +suddenly tailing off into silence, each mumbling out his own +thoughts and paying little heed to the words of his neighbour. At +the farther end was a small brazier of burning charcoal, beside +which on a three-legged wooden stool there sat a tall, thin old +man, with his jaw resting upon his two fists, and his elbows upon +his knees, staring into the fire. + +As I entered, a sallow Malay attendant had hurried up with a pipe +for me and a supply of the drug, beckoning me to an empty berth. + +"Thank you. I have not come to stay," said I. "There is a friend +of mine here, Mr. Isa Whitney, and I wish to speak with him." + +There was a movement and an exclamation from my right, and +peering through the gloom, I saw Whitney, pale, haggard, and +unkempt, staring out at me. + +"My God! It's Watson," said he. He was in a pitiable state of +reaction, with every nerve in a twitter. "I say, Watson, what +o'clock is it?" + +"Nearly eleven." + +"Of what day?" + +"Of Friday, June 19th." + +"Good heavens! I thought it was Wednesday. It is Wednesday. What +d'you want to frighten a chap for?" He sank his face onto his +arms and began to sob in a high treble key. + +"I tell you that it is Friday, man. Your wife has been waiting +this two days for you. You should be ashamed of yourself!" + +"So I am. But you've got mixed, Watson, for I have only been here +a few hours, three pipes, four pipes--I forget how many. But I'll +go home with you. I wouldn't frighten Kate--poor little Kate. +Give me your hand! Have you a cab?" + +"Yes, I have one waiting." + +"Then I shall go in it. But I must owe something. Find what I +owe, Watson. I am all off colour. I can do nothing for myself." + +I walked down the narrow passage between the double row of +sleepers, holding my breath to keep out the vile, stupefying +fumes of the drug, and looking about for the manager. As I passed +the tall man who sat by the brazier I felt a sudden pluck at my +skirt, and a low voice whispered, "Walk past me, and then look +back at me." The words fell quite distinctly upon my ear. I +glanced down. They could only have come from the old man at my +side, and yet he sat now as absorbed as ever, very thin, very +wrinkled, bent with age, an opium pipe dangling down from between +his knees, as though it had dropped in sheer lassitude from his +fingers. I took two steps forward and looked back. It took all my +self-control to prevent me from breaking out into a cry of +astonishment. He had turned his back so that none could see him +but I. His form had filled out, his wrinkles were gone, the dull +eyes had regained their fire, and there, sitting by the fire and +grinning at my surprise, was none other than Sherlock Holmes. He +made a slight motion to me to approach him, and instantly, as he +turned his face half round to the company once more, subsided +into a doddering, loose-lipped senility. + +"Holmes!" I whispered, "what on earth are you doing in this den?" + +"As low as you can," he answered; "I have excellent ears. If you +would have the great kindness to get rid of that sottish friend +of yours I should be exceedingly glad to have a little talk with +you." + +"I have a cab outside." + +"Then pray send him home in it. You may safely trust him, for he +appears to be too limp to get into any mischief. I should +recommend you also to send a note by the cabman to your wife to +say that you have thrown in your lot with me. If you will wait +outside, I shall be with you in five minutes." + +It was difficult to refuse any of Sherlock Holmes' requests, for +they were always so exceedingly definite, and put forward with +such a quiet air of mastery. I felt, however, that when Whitney +was once confined in the cab my mission was practically +accomplished; and for the rest, I could not wish anything better +than to be associated with my friend in one of those singular +adventures which were the normal condition of his existence. In a +few minutes I had written my note, paid Whitney's bill, led him +out to the cab, and seen him driven through the darkness. In a +very short time a decrepit figure had emerged from the opium den, +and I was walking down the street with Sherlock Holmes. For two +streets he shuffled along with a bent back and an uncertain foot. +Then, glancing quickly round, he straightened himself out and +burst into a hearty fit of laughter. + +"I suppose, Watson," said he, "that you imagine that I have added +opium-smoking to cocaine injections, and all the other little +weaknesses on which you have favoured me with your medical +views." + +"I was certainly surprised to find you there." + +"But not more so than I to find you." + +"I came to find a friend." + +"And I to find an enemy." + +"An enemy?" + +"Yes; one of my natural enemies, or, shall I say, my natural +prey. Briefly, Watson, I am in the midst of a very remarkable +inquiry, and I have hoped to find a clue in the incoherent +ramblings of these sots, as I have done before now. Had I been +recognised in that den my life would not have been worth an +hour's purchase; for I have used it before now for my own +purposes, and the rascally Lascar who runs it has sworn to have +vengeance upon me. There is a trap-door at the back of that +building, near the corner of Paul's Wharf, which could tell some +strange tales of what has passed through it upon the moonless +nights." + +"What! You do not mean bodies?" + +"Ay, bodies, Watson. We should be rich men if we had 1000 pounds +for every poor devil who has been done to death in that den. It +is the vilest murder-trap on the whole riverside, and I fear that +Neville St. Clair has entered it never to leave it more. But our +trap should be here." He put his two forefingers between his +teeth and whistled shrilly--a signal which was answered by a +similar whistle from the distance, followed shortly by the rattle +of wheels and the clink of horses' hoofs. + +"Now, Watson," said Holmes, as a tall dog-cart dashed up through +the gloom, throwing out two golden tunnels of yellow light from +its side lanterns. "You'll come with me, won't you?" + +"If I can be of use." + +"Oh, a trusty comrade is always of use; and a chronicler still +more so. My room at The Cedars is a double-bedded one." + +"The Cedars?" + +"Yes; that is Mr. St. Clair's house. I am staying there while I +conduct the inquiry." + +"Where is it, then?" + +"Near Lee, in Kent. We have a seven-mile drive before us." + +"But I am all in the dark." + +"Of course you are. You'll know all about it presently. Jump up +here. All right, John; we shall not need you. Here's half a +crown. Look out for me to-morrow, about eleven. Give her her +head. So long, then!" + +He flicked the horse with his whip, and we dashed away through +the endless succession of sombre and deserted streets, which +widened gradually, until we were flying across a broad +balustraded bridge, with the murky river flowing sluggishly +beneath us. Beyond lay another dull wilderness of bricks and +mortar, its silence broken only by the heavy, regular footfall of +the policeman, or the songs and shouts of some belated party of +revellers. A dull wrack was drifting slowly across the sky, and a +star or two twinkled dimly here and there through the rifts of +the clouds. Holmes drove in silence, with his head sunk upon his +breast, and the air of a man who is lost in thought, while I sat +beside him, curious to learn what this new quest might be which +seemed to tax his powers so sorely, and yet afraid to break in +upon the current of his thoughts. We had driven several miles, +and were beginning to get to the fringe of the belt of suburban +villas, when he shook himself, shrugged his shoulders, and lit up +his pipe with the air of a man who has satisfied himself that he +is acting for the best. + +"You have a grand gift of silence, Watson," said he. "It makes +you quite invaluable as a companion. 'Pon my word, it is a great +thing for me to have someone to talk to, for my own thoughts are +not over-pleasant. I was wondering what I should say to this dear +little woman to-night when she meets me at the door." + +"You forget that I know nothing about it." + +"I shall just have time to tell you the facts of the case before +we get to Lee. It seems absurdly simple, and yet, somehow I can +get nothing to go upon. There's plenty of thread, no doubt, but I +can't get the end of it into my hand. Now, I'll state the case +clearly and concisely to you, Watson, and maybe you can see a +spark where all is dark to me." + +"Proceed, then." + +"Some years ago--to be definite, in May, 1884--there came to Lee +a gentleman, Neville St. Clair by name, who appeared to have +plenty of money. He took a large villa, laid out the grounds very +nicely, and lived generally in good style. By degrees he made +friends in the neighbourhood, and in 1887 he married the daughter +of a local brewer, by whom he now has two children. He had no +occupation, but was interested in several companies and went into +town as a rule in the morning, returning by the 5:14 from Cannon +Street every night. Mr. St. Clair is now thirty-seven years of +age, is a man of temperate habits, a good husband, a very +affectionate father, and a man who is popular with all who know +him. I may add that his whole debts at the present moment, as far +as we have been able to ascertain, amount to 88 pounds 10s., while +he has 220 pounds standing to his credit in the Capital and +Counties Bank. There is no reason, therefore, to think that money +troubles have been weighing upon his mind. + +"Last Monday Mr. Neville St. Clair went into town rather earlier +than usual, remarking before he started that he had two important +commissions to perform, and that he would bring his little boy +home a box of bricks. Now, by the merest chance, his wife +received a telegram upon this same Monday, very shortly after his +departure, to the effect that a small parcel of considerable +value which she had been expecting was waiting for her at the +offices of the Aberdeen Shipping Company. Now, if you are well up +in your London, you will know that the office of the company is +in Fresno Street, which branches out of Upper Swandam Lane, where +you found me to-night. Mrs. St. Clair had her lunch, started for +the City, did some shopping, proceeded to the company's office, +got her packet, and found herself at exactly 4:35 walking through +Swandam Lane on her way back to the station. Have you followed me +so far?" + +"It is very clear." + +"If you remember, Monday was an exceedingly hot day, and Mrs. St. +Clair walked slowly, glancing about in the hope of seeing a cab, +as she did not like the neighbourhood in which she found herself. +While she was walking in this way down Swandam Lane, she suddenly +heard an ejaculation or cry, and was struck cold to see her +husband looking down at her and, as it seemed to her, beckoning +to her from a second-floor window. The window was open, and she +distinctly saw his face, which she describes as being terribly +agitated. He waved his hands frantically to her, and then +vanished from the window so suddenly that it seemed to her that +he had been plucked back by some irresistible force from behind. +One singular point which struck her quick feminine eye was that +although he wore some dark coat, such as he had started to town +in, he had on neither collar nor necktie. + +"Convinced that something was amiss with him, she rushed down the +steps--for the house was none other than the opium den in which +you found me to-night--and running through the front room she +attempted to ascend the stairs which led to the first floor. At +the foot of the stairs, however, she met this Lascar scoundrel of +whom I have spoken, who thrust her back and, aided by a Dane, who +acts as assistant there, pushed her out into the street. Filled +with the most maddening doubts and fears, she rushed down the +lane and, by rare good-fortune, met in Fresno Street a number of +constables with an inspector, all on their way to their beat. The +inspector and two men accompanied her back, and in spite of the +continued resistance of the proprietor, they made their way to +the room in which Mr. St. Clair had last been seen. There was no +sign of him there. In fact, in the whole of that floor there was +no one to be found save a crippled wretch of hideous aspect, who, +it seems, made his home there. Both he and the Lascar stoutly +swore that no one else had been in the front room during the +afternoon. So determined was their denial that the inspector was +staggered, and had almost come to believe that Mrs. St. Clair had +been deluded when, with a cry, she sprang at a small deal box +which lay upon the table and tore the lid from it. Out there fell +a cascade of children's bricks. It was the toy which he had +promised to bring home. + +"This discovery, and the evident confusion which the cripple +showed, made the inspector realise that the matter was serious. +The rooms were carefully examined, and results all pointed to an +abominable crime. The front room was plainly furnished as a +sitting-room and led into a small bedroom, which looked out upon +the back of one of the wharves. Between the wharf and the bedroom +window is a narrow strip, which is dry at low tide but is covered +at high tide with at least four and a half feet of water. The +bedroom window was a broad one and opened from below. On +examination traces of blood were to be seen upon the windowsill, +and several scattered drops were visible upon the wooden floor of +the bedroom. Thrust away behind a curtain in the front room were +all the clothes of Mr. Neville St. Clair, with the exception of +his coat. His boots, his socks, his hat, and his watch--all were +there. There were no signs of violence upon any of these +garments, and there were no other traces of Mr. Neville St. +Clair. Out of the window he must apparently have gone for no +other exit could be discovered, and the ominous bloodstains upon +the sill gave little promise that he could save himself by +swimming, for the tide was at its very highest at the moment of +the tragedy. + +"And now as to the villains who seemed to be immediately +implicated in the matter. The Lascar was known to be a man of the +vilest antecedents, but as, by Mrs. St. Clair's story, he was +known to have been at the foot of the stair within a very few +seconds of her husband's appearance at the window, he could +hardly have been more than an accessory to the crime. His defence +was one of absolute ignorance, and he protested that he had no +knowledge as to the doings of Hugh Boone, his lodger, and that he +could not account in any way for the presence of the missing +gentleman's clothes. + +"So much for the Lascar manager. Now for the sinister cripple who +lives upon the second floor of the opium den, and who was +certainly the last human being whose eyes rested upon Neville St. +Clair. His name is Hugh Boone, and his hideous face is one which +is familiar to every man who goes much to the City. He is a +professional beggar, though in order to avoid the police +regulations he pretends to a small trade in wax vestas. Some +little distance down Threadneedle Street, upon the left-hand +side, there is, as you may have remarked, a small angle in the +wall. Here it is that this creature takes his daily seat, +cross-legged with his tiny stock of matches on his lap, and as he +is a piteous spectacle a small rain of charity descends into the +greasy leather cap which lies upon the pavement beside him. I +have watched the fellow more than once before ever I thought of +making his professional acquaintance, and I have been surprised +at the harvest which he has reaped in a short time. His +appearance, you see, is so remarkable that no one can pass him +without observing him. A shock of orange hair, a pale face +disfigured by a horrible scar, which, by its contraction, has +turned up the outer edge of his upper lip, a bulldog chin, and a +pair of very penetrating dark eyes, which present a singular +contrast to the colour of his hair, all mark him out from amid +the common crowd of mendicants and so, too, does his wit, for he +is ever ready with a reply to any piece of chaff which may be +thrown at him by the passers-by. This is the man whom we now +learn to have been the lodger at the opium den, and to have been +the last man to see the gentleman of whom we are in quest." + +"But a cripple!" said I. "What could he have done single-handed +against a man in the prime of life?" + +"He is a cripple in the sense that he walks with a limp; but in +other respects he appears to be a powerful and well-nurtured man. +Surely your medical experience would tell you, Watson, that +weakness in one limb is often compensated for by exceptional +strength in the others." + +"Pray continue your narrative." + +"Mrs. St. Clair had fainted at the sight of the blood upon the +window, and she was escorted home in a cab by the police, as her +presence could be of no help to them in their investigations. +Inspector Barton, who had charge of the case, made a very careful +examination of the premises, but without finding anything which +threw any light upon the matter. One mistake had been made in not +arresting Boone instantly, as he was allowed some few minutes +during which he might have communicated with his friend the +Lascar, but this fault was soon remedied, and he was seized and +searched, without anything being found which could incriminate +him. There were, it is true, some blood-stains upon his right +shirt-sleeve, but he pointed to his ring-finger, which had been +cut near the nail, and explained that the bleeding came from +there, adding that he had been to the window not long before, and +that the stains which had been observed there came doubtless from +the same source. He denied strenuously having ever seen Mr. +Neville St. Clair and swore that the presence of the clothes in +his room was as much a mystery to him as to the police. As to +Mrs. St. Clair's assertion that she had actually seen her husband +at the window, he declared that she must have been either mad or +dreaming. He was removed, loudly protesting, to the +police-station, while the inspector remained upon the premises in +the hope that the ebbing tide might afford some fresh clue. + +"And it did, though they hardly found upon the mud-bank what they +had feared to find. It was Neville St. Clair's coat, and not +Neville St. Clair, which lay uncovered as the tide receded. And +what do you think they found in the pockets?" + +"I cannot imagine." + +"No, I don't think you would guess. Every pocket stuffed with +pennies and half-pennies--421 pennies and 270 half-pennies. It +was no wonder that it had not been swept away by the tide. But a +human body is a different matter. There is a fierce eddy between +the wharf and the house. It seemed likely enough that the +weighted coat had remained when the stripped body had been sucked +away into the river." + +"But I understand that all the other clothes were found in the +room. Would the body be dressed in a coat alone?" + +"No, sir, but the facts might be met speciously enough. Suppose +that this man Boone had thrust Neville St. Clair through the +window, there is no human eye which could have seen the deed. +What would he do then? It would of course instantly strike him +that he must get rid of the tell-tale garments. He would seize +the coat, then, and be in the act of throwing it out, when it +would occur to him that it would swim and not sink. He has little +time, for he has heard the scuffle downstairs when the wife tried +to force her way up, and perhaps he has already heard from his +Lascar confederate that the police are hurrying up the street. +There is not an instant to be lost. He rushes to some secret +hoard, where he has accumulated the fruits of his beggary, and he +stuffs all the coins upon which he can lay his hands into the +pockets to make sure of the coat's sinking. He throws it out, and +would have done the same with the other garments had not he heard +the rush of steps below, and only just had time to close the +window when the police appeared." + +"It certainly sounds feasible." + +"Well, we will take it as a working hypothesis for want of a +better. Boone, as I have told you, was arrested and taken to the +station, but it could not be shown that there had ever before +been anything against him. He had for years been known as a +professional beggar, but his life appeared to have been a very +quiet and innocent one. There the matter stands at present, and +the questions which have to be solved--what Neville St. Clair was +doing in the opium den, what happened to him when there, where is +he now, and what Hugh Boone had to do with his disappearance--are +all as far from a solution as ever. I confess that I cannot +recall any case within my experience which looked at the first +glance so simple and yet which presented such difficulties." + +While Sherlock Holmes had been detailing this singular series of +events, we had been whirling through the outskirts of the great +town until the last straggling houses had been left behind, and +we rattled along with a country hedge upon either side of us. +Just as he finished, however, we drove through two scattered +villages, where a few lights still glimmered in the windows. + +"We are on the outskirts of Lee," said my companion. "We have +touched on three English counties in our short drive, starting in +Middlesex, passing over an angle of Surrey, and ending in Kent. +See that light among the trees? That is The Cedars, and beside +that lamp sits a woman whose anxious ears have already, I have +little doubt, caught the clink of our horse's feet." + +"But why are you not conducting the case from Baker Street?" I +asked. + +"Because there are many inquiries which must be made out here. +Mrs. St. Clair has most kindly put two rooms at my disposal, and +you may rest assured that she will have nothing but a welcome for +my friend and colleague. I hate to meet her, Watson, when I have +no news of her husband. Here we are. Whoa, there, whoa!" + +We had pulled up in front of a large villa which stood within its +own grounds. A stable-boy had run out to the horse's head, and +springing down, I followed Holmes up the small, winding +gravel-drive which led to the house. As we approached, the door +flew open, and a little blonde woman stood in the opening, clad +in some sort of light mousseline de soie, with a touch of fluffy +pink chiffon at her neck and wrists. She stood with her figure +outlined against the flood of light, one hand upon the door, one +half-raised in her eagerness, her body slightly bent, her head +and face protruded, with eager eyes and parted lips, a standing +question. + +"Well?" she cried, "well?" And then, seeing that there were two +of us, she gave a cry of hope which sank into a groan as she saw +that my companion shook his head and shrugged his shoulders. + +"No good news?" + +"None." + +"No bad?" + +"No." + +"Thank God for that. But come in. You must be weary, for you have +had a long day." + +"This is my friend, Dr. Watson. He has been of most vital use to +me in several of my cases, and a lucky chance has made it +possible for me to bring him out and associate him with this +investigation." + +"I am delighted to see you," said she, pressing my hand warmly. +"You will, I am sure, forgive anything that may be wanting in our +arrangements, when you consider the blow which has come so +suddenly upon us." + +"My dear madam," said I, "I am an old campaigner, and if I were +not I can very well see that no apology is needed. If I can be of +any assistance, either to you or to my friend here, I shall be +indeed happy." + +"Now, Mr. Sherlock Holmes," said the lady as we entered a +well-lit dining-room, upon the table of which a cold supper had +been laid out, "I should very much like to ask you one or two +plain questions, to which I beg that you will give a plain +answer." + +"Certainly, madam." + +"Do not trouble about my feelings. I am not hysterical, nor given +to fainting. I simply wish to hear your real, real opinion." + +"Upon what point?" + +"In your heart of hearts, do you think that Neville is alive?" + +Sherlock Holmes seemed to be embarrassed by the question. +"Frankly, now!" she repeated, standing upon the rug and looking +keenly down at him as he leaned back in a basket-chair. + +"Frankly, then, madam, I do not." + +"You think that he is dead?" + +"I do." + +"Murdered?" + +"I don't say that. Perhaps." + +"And on what day did he meet his death?" + +"On Monday." + +"Then perhaps, Mr. Holmes, you will be good enough to explain how +it is that I have received a letter from him to-day." + +Sherlock Holmes sprang out of his chair as if he had been +galvanised. + +"What!" he roared. + +"Yes, to-day." She stood smiling, holding up a little slip of +paper in the air. + +"May I see it?" + +"Certainly." + +He snatched it from her in his eagerness, and smoothing it out +upon the table he drew over the lamp and examined it intently. I +had left my chair and was gazing at it over his shoulder. The +envelope was a very coarse one and was stamped with the Gravesend +postmark and with the date of that very day, or rather of the day +before, for it was considerably after midnight. + +"Coarse writing," murmured Holmes. "Surely this is not your +husband's writing, madam." + +"No, but the enclosure is." + +"I perceive also that whoever addressed the envelope had to go +and inquire as to the address." + +"How can you tell that?" + +"The name, you see, is in perfectly black ink, which has dried +itself. The rest is of the greyish colour, which shows that +blotting-paper has been used. If it had been written straight +off, and then blotted, none would be of a deep black shade. This +man has written the name, and there has then been a pause before +he wrote the address, which can only mean that he was not +familiar with it. It is, of course, a trifle, but there is +nothing so important as trifles. Let us now see the letter. Ha! +there has been an enclosure here!" + +"Yes, there was a ring. His signet-ring." + +"And you are sure that this is your husband's hand?" + +"One of his hands." + +"One?" + +"His hand when he wrote hurriedly. It is very unlike his usual +writing, and yet I know it well." + +"'Dearest do not be frightened. All will come well. There is a +huge error which it may take some little time to rectify. +Wait in patience.--NEVILLE.' Written in pencil upon the fly-leaf +of a book, octavo size, no water-mark. Hum! Posted to-day in +Gravesend by a man with a dirty thumb. Ha! And the flap has been +gummed, if I am not very much in error, by a person who had been +chewing tobacco. And you have no doubt that it is your husband's +hand, madam?" + +"None. Neville wrote those words." + +"And they were posted to-day at Gravesend. Well, Mrs. St. Clair, +the clouds lighten, though I should not venture to say that the +danger is over." + +"But he must be alive, Mr. Holmes." + +"Unless this is a clever forgery to put us on the wrong scent. +The ring, after all, proves nothing. It may have been taken from +him." + +"No, no; it is, it is his very own writing!" + +"Very well. It may, however, have been written on Monday and only +posted to-day." + +"That is possible." + +"If so, much may have happened between." + +"Oh, you must not discourage me, Mr. Holmes. I know that all is +well with him. There is so keen a sympathy between us that I +should know if evil came upon him. On the very day that I saw him +last he cut himself in the bedroom, and yet I in the dining-room +rushed upstairs instantly with the utmost certainty that +something had happened. Do you think that I would respond to such +a trifle and yet be ignorant of his death?" + +"I have seen too much not to know that the impression of a woman +may be more valuable than the conclusion of an analytical +reasoner. And in this letter you certainly have a very strong +piece of evidence to corroborate your view. But if your husband +is alive and able to write letters, why should he remain away +from you?" + +"I cannot imagine. It is unthinkable." + +"And on Monday he made no remarks before leaving you?" + +"No." + +"And you were surprised to see him in Swandam Lane?" + +"Very much so." + +"Was the window open?" + +"Yes." + +"Then he might have called to you?" + +"He might." + +"He only, as I understand, gave an inarticulate cry?" + +"Yes." + +"A call for help, you thought?" + +"Yes. He waved his hands." + +"But it might have been a cry of surprise. Astonishment at the +unexpected sight of you might cause him to throw up his hands?" + +"It is possible." + +"And you thought he was pulled back?" + +"He disappeared so suddenly." + +"He might have leaped back. You did not see anyone else in the +room?" + +"No, but this horrible man confessed to having been there, and +the Lascar was at the foot of the stairs." + +"Quite so. Your husband, as far as you could see, had his +ordinary clothes on?" + +"But without his collar or tie. I distinctly saw his bare +throat." + +"Had he ever spoken of Swandam Lane?" + +"Never." + +"Had he ever showed any signs of having taken opium?" + +"Never." + +"Thank you, Mrs. St. Clair. Those are the principal points about +which I wished to be absolutely clear. We shall now have a little +supper and then retire, for we may have a very busy day +to-morrow." + +A large and comfortable double-bedded room had been placed at our +disposal, and I was quickly between the sheets, for I was weary +after my night of adventure. Sherlock Holmes was a man, however, +who, when he had an unsolved problem upon his mind, would go for +days, and even for a week, without rest, turning it over, +rearranging his facts, looking at it from every point of view +until he had either fathomed it or convinced himself that his +data were insufficient. It was soon evident to me that he was now +preparing for an all-night sitting. He took off his coat and +waistcoat, put on a large blue dressing-gown, and then wandered +about the room collecting pillows from his bed and cushions from +the sofa and armchairs. With these he constructed a sort of +Eastern divan, upon which he perched himself cross-legged, with +an ounce of shag tobacco and a box of matches laid out in front +of him. In the dim light of the lamp I saw him sitting there, an +old briar pipe between his lips, his eyes fixed vacantly upon the +corner of the ceiling, the blue smoke curling up from him, +silent, motionless, with the light shining upon his strong-set +aquiline features. So he sat as I dropped off to sleep, and so he +sat when a sudden ejaculation caused me to wake up, and I found +the summer sun shining into the apartment. The pipe was still +between his lips, the smoke still curled upward, and the room was +full of a dense tobacco haze, but nothing remained of the heap of +shag which I had seen upon the previous night. + +"Awake, Watson?" he asked. + +"Yes." + +"Game for a morning drive?" + +"Certainly." + +"Then dress. No one is stirring yet, but I know where the +stable-boy sleeps, and we shall soon have the trap out." He +chuckled to himself as he spoke, his eyes twinkled, and he seemed +a different man to the sombre thinker of the previous night. + +As I dressed I glanced at my watch. It was no wonder that no one +was stirring. It was twenty-five minutes past four. I had hardly +finished when Holmes returned with the news that the boy was +putting in the horse. + +"I want to test a little theory of mine," said he, pulling on his +boots. "I think, Watson, that you are now standing in the +presence of one of the most absolute fools in Europe. I deserve +to be kicked from here to Charing Cross. But I think I have the +key of the affair now." + +"And where is it?" I asked, smiling. + +"In the bathroom," he answered. "Oh, yes, I am not joking," he +continued, seeing my look of incredulity. "I have just been +there, and I have taken it out, and I have got it in this +Gladstone bag. Come on, my boy, and we shall see whether it will +not fit the lock." + +We made our way downstairs as quietly as possible, and out into +the bright morning sunshine. In the road stood our horse and +trap, with the half-clad stable-boy waiting at the head. We both +sprang in, and away we dashed down the London Road. A few country +carts were stirring, bearing in vegetables to the metropolis, but +the lines of villas on either side were as silent and lifeless as +some city in a dream. + +"It has been in some points a singular case," said Holmes, +flicking the horse on into a gallop. "I confess that I have been +as blind as a mole, but it is better to learn wisdom late than +never to learn it at all." + +In town the earliest risers were just beginning to look sleepily +from their windows as we drove through the streets of the Surrey +side. Passing down the Waterloo Bridge Road we crossed over the +river, and dashing up Wellington Street wheeled sharply to the +right and found ourselves in Bow Street. Sherlock Holmes was well +known to the force, and the two constables at the door saluted +him. One of them held the horse's head while the other led us in. + +"Who is on duty?" asked Holmes. + +"Inspector Bradstreet, sir." + +"Ah, Bradstreet, how are you?" A tall, stout official had come +down the stone-flagged passage, in a peaked cap and frogged +jacket. "I wish to have a quiet word with you, Bradstreet." +"Certainly, Mr. Holmes. Step into my room here." It was a small, +office-like room, with a huge ledger upon the table, and a +telephone projecting from the wall. The inspector sat down at his +desk. + +"What can I do for you, Mr. Holmes?" + +"I called about that beggarman, Boone--the one who was charged +with being concerned in the disappearance of Mr. Neville St. +Clair, of Lee." + +"Yes. He was brought up and remanded for further inquiries." + +"So I heard. You have him here?" + +"In the cells." + +"Is he quiet?" + +"Oh, he gives no trouble. But he is a dirty scoundrel." + +"Dirty?" + +"Yes, it is all we can do to make him wash his hands, and his +face is as black as a tinker's. Well, when once his case has been +settled, he will have a regular prison bath; and I think, if you +saw him, you would agree with me that he needed it." + +"I should like to see him very much." + +"Would you? That is easily done. Come this way. You can leave +your bag." + +"No, I think that I'll take it." + +"Very good. Come this way, if you please." He led us down a +passage, opened a barred door, passed down a winding stair, and +brought us to a whitewashed corridor with a line of doors on each +side. + +"The third on the right is his," said the inspector. "Here it +is!" He quietly shot back a panel in the upper part of the door +and glanced through. + +"He is asleep," said he. "You can see him very well." + +We both put our eyes to the grating. The prisoner lay with his +face towards us, in a very deep sleep, breathing slowly and +heavily. He was a middle-sized man, coarsely clad as became his +calling, with a coloured shirt protruding through the rent in his +tattered coat. He was, as the inspector had said, extremely +dirty, but the grime which covered his face could not conceal its +repulsive ugliness. A broad wheal from an old scar ran right +across it from eye to chin, and by its contraction had turned up +one side of the upper lip, so that three teeth were exposed in a +perpetual snarl. A shock of very bright red hair grew low over +his eyes and forehead. + +"He's a beauty, isn't he?" said the inspector. + +"He certainly needs a wash," remarked Holmes. "I had an idea that +he might, and I took the liberty of bringing the tools with me." +He opened the Gladstone bag as he spoke, and took out, to my +astonishment, a very large bath-sponge. + +"He! he! You are a funny one," chuckled the inspector. + +"Now, if you will have the great goodness to open that door very +quietly, we will soon make him cut a much more respectable +figure." + +"Well, I don't know why not," said the inspector. "He doesn't +look a credit to the Bow Street cells, does he?" He slipped his +key into the lock, and we all very quietly entered the cell. The +sleeper half turned, and then settled down once more into a deep +slumber. Holmes stooped to the water-jug, moistened his sponge, +and then rubbed it twice vigorously across and down the +prisoner's face. + +"Let me introduce you," he shouted, "to Mr. Neville St. Clair, of +Lee, in the county of Kent." + +Never in my life have I seen such a sight. The man's face peeled +off under the sponge like the bark from a tree. Gone was the +coarse brown tint! Gone, too, was the horrid scar which had +seamed it across, and the twisted lip which had given the +repulsive sneer to the face! A twitch brought away the tangled +red hair, and there, sitting up in his bed, was a pale, +sad-faced, refined-looking man, black-haired and smooth-skinned, +rubbing his eyes and staring about him with sleepy bewilderment. +Then suddenly realising the exposure, he broke into a scream and +threw himself down with his face to the pillow. + +"Great heavens!" cried the inspector, "it is, indeed, the missing +man. I know him from the photograph." + +The prisoner turned with the reckless air of a man who abandons +himself to his destiny. "Be it so," said he. "And pray what am I +charged with?" + +"With making away with Mr. Neville St.-- Oh, come, you can't be +charged with that unless they make a case of attempted suicide of +it," said the inspector with a grin. "Well, I have been +twenty-seven years in the force, but this really takes the cake." + +"If I am Mr. Neville St. Clair, then it is obvious that no crime +has been committed, and that, therefore, I am illegally +detained." + +"No crime, but a very great error has been committed," said +Holmes. "You would have done better to have trusted your wife." + +"It was not the wife; it was the children," groaned the prisoner. +"God help me, I would not have them ashamed of their father. My +God! What an exposure! What can I do?" + +Sherlock Holmes sat down beside him on the couch and patted him +kindly on the shoulder. + +"If you leave it to a court of law to clear the matter up," said +he, "of course you can hardly avoid publicity. On the other hand, +if you convince the police authorities that there is no possible +case against you, I do not know that there is any reason that the +details should find their way into the papers. Inspector +Bradstreet would, I am sure, make notes upon anything which you +might tell us and submit it to the proper authorities. The case +would then never go into court at all." + +"God bless you!" cried the prisoner passionately. "I would have +endured imprisonment, ay, even execution, rather than have left +my miserable secret as a family blot to my children. + +"You are the first who have ever heard my story. My father was a +schoolmaster in Chesterfield, where I received an excellent +education. I travelled in my youth, took to the stage, and +finally became a reporter on an evening paper in London. One day +my editor wished to have a series of articles upon begging in the +metropolis, and I volunteered to supply them. There was the point +from which all my adventures started. It was only by trying +begging as an amateur that I could get the facts upon which to +base my articles. When an actor I had, of course, learned all the +secrets of making up, and had been famous in the green-room for +my skill. I took advantage now of my attainments. I painted my +face, and to make myself as pitiable as possible I made a good +scar and fixed one side of my lip in a twist by the aid of a +small slip of flesh-coloured plaster. Then with a red head of +hair, and an appropriate dress, I took my station in the business +part of the city, ostensibly as a match-seller but really as a +beggar. For seven hours I plied my trade, and when I returned +home in the evening I found to my surprise that I had received no +less than 26s. 4d. + +"I wrote my articles and thought little more of the matter until, +some time later, I backed a bill for a friend and had a writ +served upon me for 25 pounds. I was at my wit's end where to get +the money, but a sudden idea came to me. I begged a fortnight's +grace from the creditor, asked for a holiday from my employers, +and spent the time in begging in the City under my disguise. In +ten days I had the money and had paid the debt. + +"Well, you can imagine how hard it was to settle down to arduous +work at 2 pounds a week when I knew that I could earn as much in +a day by smearing my face with a little paint, laying my cap on +the ground, and sitting still. It was a long fight between my +pride and the money, but the dollars won at last, and I threw up +reporting and sat day after day in the corner which I had first +chosen, inspiring pity by my ghastly face and filling my pockets +with coppers. Only one man knew my secret. He was the keeper of a +low den in which I used to lodge in Swandam Lane, where I could +every morning emerge as a squalid beggar and in the evenings +transform myself into a well-dressed man about town. This fellow, +a Lascar, was well paid by me for his rooms, so that I knew that +my secret was safe in his possession. + +"Well, very soon I found that I was saving considerable sums of +money. I do not mean that any beggar in the streets of London +could earn 700 pounds a year--which is less than my average +takings--but I had exceptional advantages in my power of making +up, and also in a facility of repartee, which improved by +practice and made me quite a recognised character in the City. +All day a stream of pennies, varied by silver, poured in upon me, +and it was a very bad day in which I failed to take 2 pounds. + +"As I grew richer I grew more ambitious, took a house in the +country, and eventually married, without anyone having a +suspicion as to my real occupation. My dear wife knew that I had +business in the City. She little knew what. + +"Last Monday I had finished for the day and was dressing in my +room above the opium den when I looked out of my window and saw, +to my horror and astonishment, that my wife was standing in the +street, with her eyes fixed full upon me. I gave a cry of +surprise, threw up my arms to cover my face, and, rushing to my +confidant, the Lascar, entreated him to prevent anyone from +coming up to me. I heard her voice downstairs, but I knew that +she could not ascend. Swiftly I threw off my clothes, pulled on +those of a beggar, and put on my pigments and wig. Even a wife's +eyes could not pierce so complete a disguise. But then it +occurred to me that there might be a search in the room, and that +the clothes might betray me. I threw open the window, reopening +by my violence a small cut which I had inflicted upon myself in +the bedroom that morning. Then I seized my coat, which was +weighted by the coppers which I had just transferred to it from +the leather bag in which I carried my takings. I hurled it out of +the window, and it disappeared into the Thames. The other clothes +would have followed, but at that moment there was a rush of +constables up the stair, and a few minutes after I found, rather, +I confess, to my relief, that instead of being identified as Mr. +Neville St. Clair, I was arrested as his murderer. + +"I do not know that there is anything else for me to explain. I +was determined to preserve my disguise as long as possible, and +hence my preference for a dirty face. Knowing that my wife would +be terribly anxious, I slipped off my ring and confided it to the +Lascar at a moment when no constable was watching me, together +with a hurried scrawl, telling her that she had no cause to +fear." + +"That note only reached her yesterday," said Holmes. + +"Good God! What a week she must have spent!" + +"The police have watched this Lascar," said Inspector Bradstreet, +"and I can quite understand that he might find it difficult to +post a letter unobserved. Probably he handed it to some sailor +customer of his, who forgot all about it for some days." + +"That was it," said Holmes, nodding approvingly; "I have no doubt +of it. But have you never been prosecuted for begging?" + +"Many times; but what was a fine to me?" + +"It must stop here, however," said Bradstreet. "If the police are +to hush this thing up, there must be no more of Hugh Boone." + +"I have sworn it by the most solemn oaths which a man can take." + +"In that case I think that it is probable that no further steps +may be taken. But if you are found again, then all must come out. +I am sure, Mr. Holmes, that we are very much indebted to you for +having cleared the matter up. I wish I knew how you reach your +results." + +"I reached this one," said my friend, "by sitting upon five +pillows and consuming an ounce of shag. I think, Watson, that if +we drive to Baker Street we shall just be in time for breakfast." + + + +VII. THE ADVENTURE OF THE BLUE CARBUNCLE + +I had called upon my friend Sherlock Holmes upon the second +morning after Christmas, with the intention of wishing him the +compliments of the season. He was lounging upon the sofa in a +purple dressing-gown, a pipe-rack within his reach upon the +right, and a pile of crumpled morning papers, evidently newly +studied, near at hand. Beside the couch was a wooden chair, and +on the angle of the back hung a very seedy and disreputable +hard-felt hat, much the worse for wear, and cracked in several +places. A lens and a forceps lying upon the seat of the chair +suggested that the hat had been suspended in this manner for the +purpose of examination. + +"You are engaged," said I; "perhaps I interrupt you." + +"Not at all. I am glad to have a friend with whom I can discuss +my results. The matter is a perfectly trivial one"--he jerked his +thumb in the direction of the old hat--"but there are points in +connection with it which are not entirely devoid of interest and +even of instruction." + +I seated myself in his armchair and warmed my hands before his +crackling fire, for a sharp frost had set in, and the windows +were thick with the ice crystals. "I suppose," I remarked, "that, +homely as it looks, this thing has some deadly story linked on to +it--that it is the clue which will guide you in the solution of +some mystery and the punishment of some crime." + +"No, no. No crime," said Sherlock Holmes, laughing. "Only one of +those whimsical little incidents which will happen when you have +four million human beings all jostling each other within the +space of a few square miles. Amid the action and reaction of so +dense a swarm of humanity, every possible combination of events +may be expected to take place, and many a little problem will be +presented which may be striking and bizarre without being +criminal. We have already had experience of such." + +"So much so," I remarked, "that of the last six cases which I +have added to my notes, three have been entirely free of any +legal crime." + +"Precisely. You allude to my attempt to recover the Irene Adler +papers, to the singular case of Miss Mary Sutherland, and to the +adventure of the man with the twisted lip. Well, I have no doubt +that this small matter will fall into the same innocent category. +You know Peterson, the commissionaire?" + +"Yes." + +"It is to him that this trophy belongs." + +"It is his hat." + +"No, no, he found it. Its owner is unknown. I beg that you will +look upon it not as a battered billycock but as an intellectual +problem. And, first, as to how it came here. It arrived upon +Christmas morning, in company with a good fat goose, which is, I +have no doubt, roasting at this moment in front of Peterson's +fire. The facts are these: about four o'clock on Christmas +morning, Peterson, who, as you know, is a very honest fellow, was +returning from some small jollification and was making his way +homeward down Tottenham Court Road. In front of him he saw, in +the gaslight, a tallish man, walking with a slight stagger, and +carrying a white goose slung over his shoulder. As he reached the +corner of Goodge Street, a row broke out between this stranger +and a little knot of roughs. One of the latter knocked off the +man's hat, on which he raised his stick to defend himself and, +swinging it over his head, smashed the shop window behind him. +Peterson had rushed forward to protect the stranger from his +assailants; but the man, shocked at having broken the window, and +seeing an official-looking person in uniform rushing towards him, +dropped his goose, took to his heels, and vanished amid the +labyrinth of small streets which lie at the back of Tottenham +Court Road. The roughs had also fled at the appearance of +Peterson, so that he was left in possession of the field of +battle, and also of the spoils of victory in the shape of this +battered hat and a most unimpeachable Christmas goose." + +"Which surely he restored to their owner?" + +"My dear fellow, there lies the problem. It is true that 'For +Mrs. Henry Baker' was printed upon a small card which was tied to +the bird's left leg, and it is also true that the initials 'H. +B.' are legible upon the lining of this hat, but as there are +some thousands of Bakers, and some hundreds of Henry Bakers in +this city of ours, it is not easy to restore lost property to any +one of them." + +"What, then, did Peterson do?" + +"He brought round both hat and goose to me on Christmas morning, +knowing that even the smallest problems are of interest to me. +The goose we retained until this morning, when there were signs +that, in spite of the slight frost, it would be well that it +should be eaten without unnecessary delay. Its finder has carried +it off, therefore, to fulfil the ultimate destiny of a goose, +while I continue to retain the hat of the unknown gentleman who +lost his Christmas dinner." + +"Did he not advertise?" + +"No." + +"Then, what clue could you have as to his identity?" + +"Only as much as we can deduce." + +"From his hat?" + +"Precisely." + +"But you are joking. What can you gather from this old battered +felt?" + +"Here is my lens. You know my methods. What can you gather +yourself as to the individuality of the man who has worn this +article?" + +I took the tattered object in my hands and turned it over rather +ruefully. It was a very ordinary black hat of the usual round +shape, hard and much the worse for wear. The lining had been of +red silk, but was a good deal discoloured. There was no maker's +name; but, as Holmes had remarked, the initials "H. B." were +scrawled upon one side. It was pierced in the brim for a +hat-securer, but the elastic was missing. For the rest, it was +cracked, exceedingly dusty, and spotted in several places, +although there seemed to have been some attempt to hide the +discoloured patches by smearing them with ink. + +"I can see nothing," said I, handing it back to my friend. + +"On the contrary, Watson, you can see everything. You fail, +however, to reason from what you see. You are too timid in +drawing your inferences." + +"Then, pray tell me what it is that you can infer from this hat?" + +He picked it up and gazed at it in the peculiar introspective +fashion which was characteristic of him. "It is perhaps less +suggestive than it might have been," he remarked, "and yet there +are a few inferences which are very distinct, and a few others +which represent at least a strong balance of probability. That +the man was highly intellectual is of course obvious upon the +face of it, and also that he was fairly well-to-do within the +last three years, although he has now fallen upon evil days. He +had foresight, but has less now than formerly, pointing to a +moral retrogression, which, when taken with the decline of his +fortunes, seems to indicate some evil influence, probably drink, +at work upon him. This may account also for the obvious fact that +his wife has ceased to love him." + +"My dear Holmes!" + +"He has, however, retained some degree of self-respect," he +continued, disregarding my remonstrance. "He is a man who leads a +sedentary life, goes out little, is out of training entirely, is +middle-aged, has grizzled hair which he has had cut within the +last few days, and which he anoints with lime-cream. These are +the more patent facts which are to be deduced from his hat. Also, +by the way, that it is extremely improbable that he has gas laid +on in his house." + +"You are certainly joking, Holmes." + +"Not in the least. Is it possible that even now, when I give you +these results, you are unable to see how they are attained?" + +"I have no doubt that I am very stupid, but I must confess that I +am unable to follow you. For example, how did you deduce that +this man was intellectual?" + +For answer Holmes clapped the hat upon his head. It came right +over the forehead and settled upon the bridge of his nose. "It is +a question of cubic capacity," said he; "a man with so large a +brain must have something in it." + +"The decline of his fortunes, then?" + +"This hat is three years old. These flat brims curled at the edge +came in then. It is a hat of the very best quality. Look at the +band of ribbed silk and the excellent lining. If this man could +afford to buy so expensive a hat three years ago, and has had no +hat since, then he has assuredly gone down in the world." + +"Well, that is clear enough, certainly. But how about the +foresight and the moral retrogression?" + +Sherlock Holmes laughed. "Here is the foresight," said he putting +his finger upon the little disc and loop of the hat-securer. +"They are never sold upon hats. If this man ordered one, it is a +sign of a certain amount of foresight, since he went out of his +way to take this precaution against the wind. But since we see +that he has broken the elastic and has not troubled to replace +it, it is obvious that he has less foresight now than formerly, +which is a distinct proof of a weakening nature. On the other +hand, he has endeavoured to conceal some of these stains upon the +felt by daubing them with ink, which is a sign that he has not +entirely lost his self-respect." + +"Your reasoning is certainly plausible." + +"The further points, that he is middle-aged, that his hair is +grizzled, that it has been recently cut, and that he uses +lime-cream, are all to be gathered from a close examination of the +lower part of the lining. The lens discloses a large number of +hair-ends, clean cut by the scissors of the barber. They all +appear to be adhesive, and there is a distinct odour of +lime-cream. This dust, you will observe, is not the gritty, grey +dust of the street but the fluffy brown dust of the house, +showing that it has been hung up indoors most of the time, while +the marks of moisture upon the inside are proof positive that the +wearer perspired very freely, and could therefore, hardly be in +the best of training." + +"But his wife--you said that she had ceased to love him." + +"This hat has not been brushed for weeks. When I see you, my dear +Watson, with a week's accumulation of dust upon your hat, and +when your wife allows you to go out in such a state, I shall fear +that you also have been unfortunate enough to lose your wife's +affection." + +"But he might be a bachelor." + +"Nay, he was bringing home the goose as a peace-offering to his +wife. Remember the card upon the bird's leg." + +"You have an answer to everything. But how on earth do you deduce +that the gas is not laid on in his house?" + +"One tallow stain, or even two, might come by chance; but when I +see no less than five, I think that there can be little doubt +that the individual must be brought into frequent contact with +burning tallow--walks upstairs at night probably with his hat in +one hand and a guttering candle in the other. Anyhow, he never +got tallow-stains from a gas-jet. Are you satisfied?" + +"Well, it is very ingenious," said I, laughing; "but since, as +you said just now, there has been no crime committed, and no harm +done save the loss of a goose, all this seems to be rather a +waste of energy." + +Sherlock Holmes had opened his mouth to reply, when the door flew +open, and Peterson, the commissionaire, rushed into the apartment +with flushed cheeks and the face of a man who is dazed with +astonishment. + +"The goose, Mr. Holmes! The goose, sir!" he gasped. + +"Eh? What of it, then? Has it returned to life and flapped off +through the kitchen window?" Holmes twisted himself round upon +the sofa to get a fairer view of the man's excited face. + +"See here, sir! See what my wife found in its crop!" He held out +his hand and displayed upon the centre of the palm a brilliantly +scintillating blue stone, rather smaller than a bean in size, but +of such purity and radiance that it twinkled like an electric +point in the dark hollow of his hand. + +Sherlock Holmes sat up with a whistle. "By Jove, Peterson!" said +he, "this is treasure trove indeed. I suppose you know what you +have got?" + +"A diamond, sir? A precious stone. It cuts into glass as though +it were putty." + +"It's more than a precious stone. It is the precious stone." + +"Not the Countess of Morcar's blue carbuncle!" I ejaculated. + +"Precisely so. I ought to know its size and shape, seeing that I +have read the advertisement about it in The Times every day +lately. It is absolutely unique, and its value can only be +conjectured, but the reward offered of 1000 pounds is certainly +not within a twentieth part of the market price." + +"A thousand pounds! Great Lord of mercy!" The commissionaire +plumped down into a chair and stared from one to the other of us. + +"That is the reward, and I have reason to know that there are +sentimental considerations in the background which would induce +the Countess to part with half her fortune if she could but +recover the gem." + +"It was lost, if I remember aright, at the Hotel Cosmopolitan," I +remarked. + +"Precisely so, on December 22nd, just five days ago. John Horner, +a plumber, was accused of having abstracted it from the lady's +jewel-case. The evidence against him was so strong that the case +has been referred to the Assizes. I have some account of the +matter here, I believe." He rummaged amid his newspapers, +glancing over the dates, until at last he smoothed one out, +doubled it over, and read the following paragraph: + +"Hotel Cosmopolitan Jewel Robbery. John Horner, 26, plumber, was +brought up upon the charge of having upon the 22nd inst., +abstracted from the jewel-case of the Countess of Morcar the +valuable gem known as the blue carbuncle. James Ryder, +upper-attendant at the hotel, gave his evidence to the effect +that he had shown Horner up to the dressing-room of the Countess +of Morcar upon the day of the robbery in order that he might +solder the second bar of the grate, which was loose. He had +remained with Horner some little time, but had finally been +called away. On returning, he found that Horner had disappeared, +that the bureau had been forced open, and that the small morocco +casket in which, as it afterwards transpired, the Countess was +accustomed to keep her jewel, was lying empty upon the +dressing-table. Ryder instantly gave the alarm, and Horner was +arrested the same evening; but the stone could not be found +either upon his person or in his rooms. Catherine Cusack, maid to +the Countess, deposed to having heard Ryder's cry of dismay on +discovering the robbery, and to having rushed into the room, +where she found matters as described by the last witness. +Inspector Bradstreet, B division, gave evidence as to the arrest +of Horner, who struggled frantically, and protested his innocence +in the strongest terms. Evidence of a previous conviction for +robbery having been given against the prisoner, the magistrate +refused to deal summarily with the offence, but referred it to +the Assizes. Horner, who had shown signs of intense emotion +during the proceedings, fainted away at the conclusion and was +carried out of court." + +"Hum! So much for the police-court," said Holmes thoughtfully, +tossing aside the paper. "The question for us now to solve is the +sequence of events leading from a rifled jewel-case at one end to +the crop of a goose in Tottenham Court Road at the other. You +see, Watson, our little deductions have suddenly assumed a much +more important and less innocent aspect. Here is the stone; the +stone came from the goose, and the goose came from Mr. Henry +Baker, the gentleman with the bad hat and all the other +characteristics with which I have bored you. So now we must set +ourselves very seriously to finding this gentleman and +ascertaining what part he has played in this little mystery. To +do this, we must try the simplest means first, and these lie +undoubtedly in an advertisement in all the evening papers. If +this fail, I shall have recourse to other methods." + +"What will you say?" + +"Give me a pencil and that slip of paper. Now, then: 'Found at +the corner of Goodge Street, a goose and a black felt hat. Mr. +Henry Baker can have the same by applying at 6:30 this evening at +221B, Baker Street.' That is clear and concise." + +"Very. But will he see it?" + +"Well, he is sure to keep an eye on the papers, since, to a poor +man, the loss was a heavy one. He was clearly so scared by his +mischance in breaking the window and by the approach of Peterson +that he thought of nothing but flight, but since then he must +have bitterly regretted the impulse which caused him to drop his +bird. Then, again, the introduction of his name will cause him to +see it, for everyone who knows him will direct his attention to +it. Here you are, Peterson, run down to the advertising agency +and have this put in the evening papers." + +"In which, sir?" + +"Oh, in the Globe, Star, Pall Mall, St. James's, Evening News, +Standard, Echo, and any others that occur to you." + +"Very well, sir. And this stone?" + +"Ah, yes, I shall keep the stone. Thank you. And, I say, +Peterson, just buy a goose on your way back and leave it here +with me, for we must have one to give to this gentleman in place +of the one which your family is now devouring." + +When the commissionaire had gone, Holmes took up the stone and +held it against the light. "It's a bonny thing," said he. "Just +see how it glints and sparkles. Of course it is a nucleus and +focus of crime. Every good stone is. They are the devil's pet +baits. In the larger and older jewels every facet may stand for a +bloody deed. This stone is not yet twenty years old. It was found +in the banks of the Amoy River in southern China and is remarkable +in having every characteristic of the carbuncle, save that it is +blue in shade instead of ruby red. In spite of its youth, it has +already a sinister history. There have been two murders, a +vitriol-throwing, a suicide, and several robberies brought about +for the sake of this forty-grain weight of crystallised charcoal. +Who would think that so pretty a toy would be a purveyor to the +gallows and the prison? I'll lock it up in my strong box now and +drop a line to the Countess to say that we have it." + +"Do you think that this man Horner is innocent?" + +"I cannot tell." + +"Well, then, do you imagine that this other one, Henry Baker, had +anything to do with the matter?" + +"It is, I think, much more likely that Henry Baker is an +absolutely innocent man, who had no idea that the bird which he +was carrying was of considerably more value than if it were made +of solid gold. That, however, I shall determine by a very simple +test if we have an answer to our advertisement." + +"And you can do nothing until then?" + +"Nothing." + +"In that case I shall continue my professional round. But I shall +come back in the evening at the hour you have mentioned, for I +should like to see the solution of so tangled a business." + +"Very glad to see you. I dine at seven. There is a woodcock, I +believe. By the way, in view of recent occurrences, perhaps I +ought to ask Mrs. Hudson to examine its crop." + +I had been delayed at a case, and it was a little after half-past +six when I found myself in Baker Street once more. As I +approached the house I saw a tall man in a Scotch bonnet with a +coat which was buttoned up to his chin waiting outside in the +bright semicircle which was thrown from the fanlight. Just as I +arrived the door was opened, and we were shown up together to +Holmes' room. + +"Mr. Henry Baker, I believe," said he, rising from his armchair +and greeting his visitor with the easy air of geniality which he +could so readily assume. "Pray take this chair by the fire, Mr. +Baker. It is a cold night, and I observe that your circulation is +more adapted for summer than for winter. Ah, Watson, you have +just come at the right time. Is that your hat, Mr. Baker?" + +"Yes, sir, that is undoubtedly my hat." + +He was a large man with rounded shoulders, a massive head, and a +broad, intelligent face, sloping down to a pointed beard of +grizzled brown. A touch of red in nose and cheeks, with a slight +tremor of his extended hand, recalled Holmes' surmise as to his +habits. His rusty black frock-coat was buttoned right up in +front, with the collar turned up, and his lank wrists protruded +from his sleeves without a sign of cuff or shirt. He spoke in a +slow staccato fashion, choosing his words with care, and gave the +impression generally of a man of learning and letters who had had +ill-usage at the hands of fortune. + +"We have retained these things for some days," said Holmes, +"because we expected to see an advertisement from you giving your +address. I am at a loss to know now why you did not advertise." + +Our visitor gave a rather shamefaced laugh. "Shillings have not +been so plentiful with me as they once were," he remarked. "I had +no doubt that the gang of roughs who assaulted me had carried off +both my hat and the bird. I did not care to spend more money in a +hopeless attempt at recovering them." + +"Very naturally. By the way, about the bird, we were compelled to +eat it." + +"To eat it!" Our visitor half rose from his chair in his +excitement. + +"Yes, it would have been of no use to anyone had we not done so. +But I presume that this other goose upon the sideboard, which is +about the same weight and perfectly fresh, will answer your +purpose equally well?" + +"Oh, certainly, certainly," answered Mr. Baker with a sigh of +relief. + +"Of course, we still have the feathers, legs, crop, and so on of +your own bird, so if you wish--" + +The man burst into a hearty laugh. "They might be useful to me as +relics of my adventure," said he, "but beyond that I can hardly +see what use the disjecta membra of my late acquaintance are +going to be to me. No, sir, I think that, with your permission, I +will confine my attentions to the excellent bird which I perceive +upon the sideboard." + +Sherlock Holmes glanced sharply across at me with a slight shrug +of his shoulders. + +"There is your hat, then, and there your bird," said he. "By the +way, would it bore you to tell me where you got the other one +from? I am somewhat of a fowl fancier, and I have seldom seen a +better grown goose." + +"Certainly, sir," said Baker, who had risen and tucked his newly +gained property under his arm. "There are a few of us who +frequent the Alpha Inn, near the Museum--we are to be found in +the Museum itself during the day, you understand. This year our +good host, Windigate by name, instituted a goose club, by which, +on consideration of some few pence every week, we were each to +receive a bird at Christmas. My pence were duly paid, and the +rest is familiar to you. I am much indebted to you, sir, for a +Scotch bonnet is fitted neither to my years nor my gravity." With +a comical pomposity of manner he bowed solemnly to both of us and +strode off upon his way. + +"So much for Mr. Henry Baker," said Holmes when he had closed the +door behind him. "It is quite certain that he knows nothing +whatever about the matter. Are you hungry, Watson?" + +"Not particularly." + +"Then I suggest that we turn our dinner into a supper and follow +up this clue while it is still hot." + +"By all means." + +It was a bitter night, so we drew on our ulsters and wrapped +cravats about our throats. Outside, the stars were shining coldly +in a cloudless sky, and the breath of the passers-by blew out +into smoke like so many pistol shots. Our footfalls rang out +crisply and loudly as we swung through the doctors' quarter, +Wimpole Street, Harley Street, and so through Wigmore Street into +Oxford Street. In a quarter of an hour we were in Bloomsbury at +the Alpha Inn, which is a small public-house at the corner of one +of the streets which runs down into Holborn. Holmes pushed open +the door of the private bar and ordered two glasses of beer from +the ruddy-faced, white-aproned landlord. + +"Your beer should be excellent if it is as good as your geese," +said he. + +"My geese!" The man seemed surprised. + +"Yes. I was speaking only half an hour ago to Mr. Henry Baker, +who was a member of your goose club." + +"Ah! yes, I see. But you see, sir, them's not our geese." + +"Indeed! Whose, then?" + +"Well, I got the two dozen from a salesman in Covent Garden." + +"Indeed? I know some of them. Which was it?" + +"Breckinridge is his name." + +"Ah! I don't know him. Well, here's your good health landlord, +and prosperity to your house. Good-night." + +"Now for Mr. Breckinridge," he continued, buttoning up his coat +as we came out into the frosty air. "Remember, Watson that though +we have so homely a thing as a goose at one end of this chain, we +have at the other a man who will certainly get seven years' penal +servitude unless we can establish his innocence. It is possible +that our inquiry may but confirm his guilt; but, in any case, we +have a line of investigation which has been missed by the police, +and which a singular chance has placed in our hands. Let us +follow it out to the bitter end. Faces to the south, then, and +quick march!" + +We passed across Holborn, down Endell Street, and so through a +zigzag of slums to Covent Garden Market. One of the largest +stalls bore the name of Breckinridge upon it, and the proprietor +a horsey-looking man, with a sharp face and trim side-whiskers was +helping a boy to put up the shutters. + +"Good-evening. It's a cold night," said Holmes. + +The salesman nodded and shot a questioning glance at my +companion. + +"Sold out of geese, I see," continued Holmes, pointing at the +bare slabs of marble. + +"Let you have five hundred to-morrow morning." + +"That's no good." + +"Well, there are some on the stall with the gas-flare." + +"Ah, but I was recommended to you." + +"Who by?" + +"The landlord of the Alpha." + +"Oh, yes; I sent him a couple of dozen." + +"Fine birds they were, too. Now where did you get them from?" + +To my surprise the question provoked a burst of anger from the +salesman. + +"Now, then, mister," said he, with his head cocked and his arms +akimbo, "what are you driving at? Let's have it straight, now." + +"It is straight enough. I should like to know who sold you the +geese which you supplied to the Alpha." + +"Well then, I shan't tell you. So now!" + +"Oh, it is a matter of no importance; but I don't know why you +should be so warm over such a trifle." + +"Warm! You'd be as warm, maybe, if you were as pestered as I am. +When I pay good money for a good article there should be an end +of the business; but it's 'Where are the geese?' and 'Who did you +sell the geese to?' and 'What will you take for the geese?' One +would think they were the only geese in the world, to hear the +fuss that is made over them." + +"Well, I have no connection with any other people who have been +making inquiries," said Holmes carelessly. "If you won't tell us +the bet is off, that is all. But I'm always ready to back my +opinion on a matter of fowls, and I have a fiver on it that the +bird I ate is country bred." + +"Well, then, you've lost your fiver, for it's town bred," snapped +the salesman. + +"It's nothing of the kind." + +"I say it is." + +"I don't believe it." + +"D'you think you know more about fowls than I, who have handled +them ever since I was a nipper? I tell you, all those birds that +went to the Alpha were town bred." + +"You'll never persuade me to believe that." + +"Will you bet, then?" + +"It's merely taking your money, for I know that I am right. But +I'll have a sovereign on with you, just to teach you not to be +obstinate." + +The salesman chuckled grimly. "Bring me the books, Bill," said +he. + +The small boy brought round a small thin volume and a great +greasy-backed one, laying them out together beneath the hanging +lamp. + +"Now then, Mr. Cocksure," said the salesman, "I thought that I +was out of geese, but before I finish you'll find that there is +still one left in my shop. You see this little book?" + +"Well?" + +"That's the list of the folk from whom I buy. D'you see? Well, +then, here on this page are the country folk, and the numbers +after their names are where their accounts are in the big ledger. +Now, then! You see this other page in red ink? Well, that is a +list of my town suppliers. Now, look at that third name. Just +read it out to me." + +"Mrs. Oakshott, 117, Brixton Road--249," read Holmes. + +"Quite so. Now turn that up in the ledger." + +Holmes turned to the page indicated. "Here you are, 'Mrs. +Oakshott, 117, Brixton Road, egg and poultry supplier.'" + +"Now, then, what's the last entry?" + +"'December 22nd. Twenty-four geese at 7s. 6d.'" + +"Quite so. There you are. And underneath?" + +"'Sold to Mr. Windigate of the Alpha, at 12s.'" + +"What have you to say now?" + +Sherlock Holmes looked deeply chagrined. He drew a sovereign from +his pocket and threw it down upon the slab, turning away with the +air of a man whose disgust is too deep for words. A few yards off +he stopped under a lamp-post and laughed in the hearty, noiseless +fashion which was peculiar to him. + +"When you see a man with whiskers of that cut and the 'Pink 'un' +protruding out of his pocket, you can always draw him by a bet," +said he. "I daresay that if I had put 100 pounds down in front of +him, that man would not have given me such complete information +as was drawn from him by the idea that he was doing me on a +wager. Well, Watson, we are, I fancy, nearing the end of our +quest, and the only point which remains to be determined is +whether we should go on to this Mrs. Oakshott to-night, or +whether we should reserve it for to-morrow. It is clear from what +that surly fellow said that there are others besides ourselves +who are anxious about the matter, and I should--" + +His remarks were suddenly cut short by a loud hubbub which broke +out from the stall which we had just left. Turning round we saw a +little rat-faced fellow standing in the centre of the circle of +yellow light which was thrown by the swinging lamp, while +Breckinridge, the salesman, framed in the door of his stall, was +shaking his fists fiercely at the cringing figure. + +"I've had enough of you and your geese," he shouted. "I wish you +were all at the devil together. If you come pestering me any more +with your silly talk I'll set the dog at you. You bring Mrs. +Oakshott here and I'll answer her, but what have you to do with +it? Did I buy the geese off you?" + +"No; but one of them was mine all the same," whined the little +man. + +"Well, then, ask Mrs. Oakshott for it." + +"She told me to ask you." + +"Well, you can ask the King of Proosia, for all I care. I've had +enough of it. Get out of this!" He rushed fiercely forward, and +the inquirer flitted away into the darkness. + +"Ha! this may save us a visit to Brixton Road," whispered Holmes. +"Come with me, and we will see what is to be made of this +fellow." Striding through the scattered knots of people who +lounged round the flaring stalls, my companion speedily overtook +the little man and touched him upon the shoulder. He sprang +round, and I could see in the gas-light that every vestige of +colour had been driven from his face. + +"Who are you, then? What do you want?" he asked in a quavering +voice. + +"You will excuse me," said Holmes blandly, "but I could not help +overhearing the questions which you put to the salesman just now. +I think that I could be of assistance to you." + +"You? Who are you? How could you know anything of the matter?" + +"My name is Sherlock Holmes. It is my business to know what other +people don't know." + +"But you can know nothing of this?" + +"Excuse me, I know everything of it. You are endeavouring to +trace some geese which were sold by Mrs. Oakshott, of Brixton +Road, to a salesman named Breckinridge, by him in turn to Mr. +Windigate, of the Alpha, and by him to his club, of which Mr. +Henry Baker is a member." + +"Oh, sir, you are the very man whom I have longed to meet," cried +the little fellow with outstretched hands and quivering fingers. +"I can hardly explain to you how interested I am in this matter." + +Sherlock Holmes hailed a four-wheeler which was passing. "In that +case we had better discuss it in a cosy room rather than in this +wind-swept market-place," said he. "But pray tell me, before we +go farther, who it is that I have the pleasure of assisting." + +The man hesitated for an instant. "My name is John Robinson," he +answered with a sidelong glance. + +"No, no; the real name," said Holmes sweetly. "It is always +awkward doing business with an alias." + +A flush sprang to the white cheeks of the stranger. "Well then," +said he, "my real name is James Ryder." + +"Precisely so. Head attendant at the Hotel Cosmopolitan. Pray +step into the cab, and I shall soon be able to tell you +everything which you would wish to know." + +The little man stood glancing from one to the other of us with +half-frightened, half-hopeful eyes, as one who is not sure +whether he is on the verge of a windfall or of a catastrophe. +Then he stepped into the cab, and in half an hour we were back in +the sitting-room at Baker Street. Nothing had been said during +our drive, but the high, thin breathing of our new companion, and +the claspings and unclaspings of his hands, spoke of the nervous +tension within him. + +"Here we are!" said Holmes cheerily as we filed into the room. +"The fire looks very seasonable in this weather. You look cold, +Mr. Ryder. Pray take the basket-chair. I will just put on my +slippers before we settle this little matter of yours. Now, then! +You want to know what became of those geese?" + +"Yes, sir." + +"Or rather, I fancy, of that goose. It was one bird, I imagine in +which you were interested--white, with a black bar across the +tail." + +Ryder quivered with emotion. "Oh, sir," he cried, "can you tell +me where it went to?" + +"It came here." + +"Here?" + +"Yes, and a most remarkable bird it proved. I don't wonder that +you should take an interest in it. It laid an egg after it was +dead--the bonniest, brightest little blue egg that ever was seen. +I have it here in my museum." + +Our visitor staggered to his feet and clutched the mantelpiece +with his right hand. Holmes unlocked his strong-box and held up +the blue carbuncle, which shone out like a star, with a cold, +brilliant, many-pointed radiance. Ryder stood glaring with a +drawn face, uncertain whether to claim or to disown it. + +"The game's up, Ryder," said Holmes quietly. "Hold up, man, or +you'll be into the fire! Give him an arm back into his chair, +Watson. He's not got blood enough to go in for felony with +impunity. Give him a dash of brandy. So! Now he looks a little +more human. What a shrimp it is, to be sure!" + +For a moment he had staggered and nearly fallen, but the brandy +brought a tinge of colour into his cheeks, and he sat staring +with frightened eyes at his accuser. + +"I have almost every link in my hands, and all the proofs which I +could possibly need, so there is little which you need tell me. +Still, that little may as well be cleared up to make the case +complete. You had heard, Ryder, of this blue stone of the +Countess of Morcar's?" + +"It was Catherine Cusack who told me of it," said he in a +crackling voice. + +"I see--her ladyship's waiting-maid. Well, the temptation of +sudden wealth so easily acquired was too much for you, as it has +been for better men before you; but you were not very scrupulous +in the means you used. It seems to me, Ryder, that there is the +making of a very pretty villain in you. You knew that this man +Horner, the plumber, had been concerned in some such matter +before, and that suspicion would rest the more readily upon him. +What did you do, then? You made some small job in my lady's +room--you and your confederate Cusack--and you managed that he +should be the man sent for. Then, when he had left, you rifled +the jewel-case, raised the alarm, and had this unfortunate man +arrested. You then--" + +Ryder threw himself down suddenly upon the rug and clutched at my +companion's knees. "For God's sake, have mercy!" he shrieked. +"Think of my father! Of my mother! It would break their hearts. I +never went wrong before! I never will again. I swear it. I'll +swear it on a Bible. Oh, don't bring it into court! For Christ's +sake, don't!" + +"Get back into your chair!" said Holmes sternly. "It is very well +to cringe and crawl now, but you thought little enough of this +poor Horner in the dock for a crime of which he knew nothing." + +"I will fly, Mr. Holmes. I will leave the country, sir. Then the +charge against him will break down." + +"Hum! We will talk about that. And now let us hear a true account +of the next act. How came the stone into the goose, and how came +the goose into the open market? Tell us the truth, for there lies +your only hope of safety." + +Ryder passed his tongue over his parched lips. "I will tell you +it just as it happened, sir," said he. "When Horner had been +arrested, it seemed to me that it would be best for me to get +away with the stone at once, for I did not know at what moment +the police might not take it into their heads to search me and my +room. There was no place about the hotel where it would be safe. +I went out, as if on some commission, and I made for my sister's +house. She had married a man named Oakshott, and lived in Brixton +Road, where she fattened fowls for the market. All the way there +every man I met seemed to me to be a policeman or a detective; +and, for all that it was a cold night, the sweat was pouring down +my face before I came to the Brixton Road. My sister asked me +what was the matter, and why I was so pale; but I told her that I +had been upset by the jewel robbery at the hotel. Then I went +into the back yard and smoked a pipe and wondered what it would +be best to do. + +"I had a friend once called Maudsley, who went to the bad, and +has just been serving his time in Pentonville. One day he had met +me, and fell into talk about the ways of thieves, and how they +could get rid of what they stole. I knew that he would be true to +me, for I knew one or two things about him; so I made up my mind +to go right on to Kilburn, where he lived, and take him into my +confidence. He would show me how to turn the stone into money. +But how to get to him in safety? I thought of the agonies I had +gone through in coming from the hotel. I might at any moment be +seized and searched, and there would be the stone in my waistcoat +pocket. I was leaning against the wall at the time and looking at +the geese which were waddling about round my feet, and suddenly +an idea came into my head which showed me how I could beat the +best detective that ever lived. + +"My sister had told me some weeks before that I might have the +pick of her geese for a Christmas present, and I knew that she +was always as good as her word. I would take my goose now, and in +it I would carry my stone to Kilburn. There was a little shed in +the yard, and behind this I drove one of the birds--a fine big +one, white, with a barred tail. I caught it, and prying its bill +open, I thrust the stone down its throat as far as my finger +could reach. The bird gave a gulp, and I felt the stone pass +along its gullet and down into its crop. But the creature flapped +and struggled, and out came my sister to know what was the +matter. As I turned to speak to her the brute broke loose and +fluttered off among the others. + +"'Whatever were you doing with that bird, Jem?' says she. + +"'Well,' said I, 'you said you'd give me one for Christmas, and I +was feeling which was the fattest.' + +"'Oh,' says she, 'we've set yours aside for you--Jem's bird, we +call it. It's the big white one over yonder. There's twenty-six +of them, which makes one for you, and one for us, and two dozen +for the market.' + +"'Thank you, Maggie,' says I; 'but if it is all the same to you, +I'd rather have that one I was handling just now.' + +"'The other is a good three pound heavier,' said she, 'and we +fattened it expressly for you.' + +"'Never mind. I'll have the other, and I'll take it now,' said I. + +"'Oh, just as you like,' said she, a little huffed. 'Which is it +you want, then?' + +"'That white one with the barred tail, right in the middle of the +flock.' + +"'Oh, very well. Kill it and take it with you.' + +"Well, I did what she said, Mr. Holmes, and I carried the bird +all the way to Kilburn. I told my pal what I had done, for he was +a man that it was easy to tell a thing like that to. He laughed +until he choked, and we got a knife and opened the goose. My +heart turned to water, for there was no sign of the stone, and I +knew that some terrible mistake had occurred. I left the bird, +rushed back to my sister's, and hurried into the back yard. There +was not a bird to be seen there. + +"'Where are they all, Maggie?' I cried. + +"'Gone to the dealer's, Jem.' + +"'Which dealer's?' + +"'Breckinridge, of Covent Garden.' + +"'But was there another with a barred tail?' I asked, 'the same +as the one I chose?' + +"'Yes, Jem; there were two barred-tailed ones, and I could never +tell them apart.' + +"Well, then, of course I saw it all, and I ran off as hard as my +feet would carry me to this man Breckinridge; but he had sold the +lot at once, and not one word would he tell me as to where they +had gone. You heard him yourselves to-night. Well, he has always +answered me like that. My sister thinks that I am going mad. +Sometimes I think that I am myself. And now--and now I am myself +a branded thief, without ever having touched the wealth for which +I sold my character. God help me! God help me!" He burst into +convulsive sobbing, with his face buried in his hands. + +There was a long silence, broken only by his heavy breathing and +by the measured tapping of Sherlock Holmes' finger-tips upon the +edge of the table. Then my friend rose and threw open the door. + +"Get out!" said he. + +"What, sir! Oh, Heaven bless you!" + +"No more words. Get out!" + +And no more words were needed. There was a rush, a clatter upon +the stairs, the bang of a door, and the crisp rattle of running +footfalls from the street. + +"After all, Watson," said Holmes, reaching up his hand for his +clay pipe, "I am not retained by the police to supply their +deficiencies. If Horner were in danger it would be another thing; +but this fellow will not appear against him, and the case must +collapse. I suppose that I am commuting a felony, but it is just +possible that I am saving a soul. This fellow will not go wrong +again; he is too terribly frightened. Send him to gaol now, and +you make him a gaol-bird for life. Besides, it is the season of +forgiveness. Chance has put in our way a most singular and +whimsical problem, and its solution is its own reward. If you +will have the goodness to touch the bell, Doctor, we will begin +another investigation, in which, also a bird will be the chief +feature." + + + +VIII. THE ADVENTURE OF THE SPECKLED BAND + +On glancing over my notes of the seventy odd cases in which I +have during the last eight years studied the methods of my friend +Sherlock Holmes, I find many tragic, some comic, a large number +merely strange, but none commonplace; for, working as he did +rather for the love of his art than for the acquirement of +wealth, he refused to associate himself with any investigation +which did not tend towards the unusual, and even the fantastic. +Of all these varied cases, however, I cannot recall any which +presented more singular features than that which was associated +with the well-known Surrey family of the Roylotts of Stoke Moran. +The events in question occurred in the early days of my +association with Holmes, when we were sharing rooms as bachelors +in Baker Street. It is possible that I might have placed them +upon record before, but a promise of secrecy was made at the +time, from which I have only been freed during the last month by +the untimely death of the lady to whom the pledge was given. It +is perhaps as well that the facts should now come to light, for I +have reasons to know that there are widespread rumours as to the +death of Dr. Grimesby Roylott which tend to make the matter even +more terrible than the truth. + +It was early in April in the year '83 that I woke one morning to +find Sherlock Holmes standing, fully dressed, by the side of my +bed. He was a late riser, as a rule, and as the clock on the +mantelpiece showed me that it was only a quarter-past seven, I +blinked up at him in some surprise, and perhaps just a little +resentment, for I was myself regular in my habits. + +"Very sorry to knock you up, Watson," said he, "but it's the +common lot this morning. Mrs. Hudson has been knocked up, she +retorted upon me, and I on you." + +"What is it, then--a fire?" + +"No; a client. It seems that a young lady has arrived in a +considerable state of excitement, who insists upon seeing me. She +is waiting now in the sitting-room. Now, when young ladies wander +about the metropolis at this hour of the morning, and knock +sleepy people up out of their beds, I presume that it is +something very pressing which they have to communicate. Should it +prove to be an interesting case, you would, I am sure, wish to +follow it from the outset. I thought, at any rate, that I should +call you and give you the chance." + +"My dear fellow, I would not miss it for anything." + +I had no keener pleasure than in following Holmes in his +professional investigations, and in admiring the rapid +deductions, as swift as intuitions, and yet always founded on a +logical basis with which he unravelled the problems which were +submitted to him. I rapidly threw on my clothes and was ready in +a few minutes to accompany my friend down to the sitting-room. A +lady dressed in black and heavily veiled, who had been sitting in +the window, rose as we entered. + +"Good-morning, madam," said Holmes cheerily. "My name is Sherlock +Holmes. This is my intimate friend and associate, Dr. Watson, +before whom you can speak as freely as before myself. Ha! I am +glad to see that Mrs. Hudson has had the good sense to light the +fire. Pray draw up to it, and I shall order you a cup of hot +coffee, for I observe that you are shivering." + +"It is not cold which makes me shiver," said the woman in a low +voice, changing her seat as requested. + +"What, then?" + +"It is fear, Mr. Holmes. It is terror." She raised her veil as +she spoke, and we could see that she was indeed in a pitiable +state of agitation, her face all drawn and grey, with restless +frightened eyes, like those of some hunted animal. Her features +and figure were those of a woman of thirty, but her hair was shot +with premature grey, and her expression was weary and haggard. +Sherlock Holmes ran her over with one of his quick, +all-comprehensive glances. + +"You must not fear," said he soothingly, bending forward and +patting her forearm. "We shall soon set matters right, I have no +doubt. You have come in by train this morning, I see." + +"You know me, then?" + +"No, but I observe the second half of a return ticket in the palm +of your left glove. You must have started early, and yet you had +a good drive in a dog-cart, along heavy roads, before you reached +the station." + +The lady gave a violent start and stared in bewilderment at my +companion. + +"There is no mystery, my dear madam," said he, smiling. "The left +arm of your jacket is spattered with mud in no less than seven +places. The marks are perfectly fresh. There is no vehicle save a +dog-cart which throws up mud in that way, and then only when you +sit on the left-hand side of the driver." + +"Whatever your reasons may be, you are perfectly correct," said +she. "I started from home before six, reached Leatherhead at +twenty past, and came in by the first train to Waterloo. Sir, I +can stand this strain no longer; I shall go mad if it continues. +I have no one to turn to--none, save only one, who cares for me, +and he, poor fellow, can be of little aid. I have heard of you, +Mr. Holmes; I have heard of you from Mrs. Farintosh, whom you +helped in the hour of her sore need. It was from her that I had +your address. Oh, sir, do you not think that you could help me, +too, and at least throw a little light through the dense darkness +which surrounds me? At present it is out of my power to reward +you for your services, but in a month or six weeks I shall be +married, with the control of my own income, and then at least you +shall not find me ungrateful." + +Holmes turned to his desk and, unlocking it, drew out a small +case-book, which he consulted. + +"Farintosh," said he. "Ah yes, I recall the case; it was +concerned with an opal tiara. I think it was before your time, +Watson. I can only say, madam, that I shall be happy to devote +the same care to your case as I did to that of your friend. As to +reward, my profession is its own reward; but you are at liberty +to defray whatever expenses I may be put to, at the time which +suits you best. And now I beg that you will lay before us +everything that may help us in forming an opinion upon the +matter." + +"Alas!" replied our visitor, "the very horror of my situation +lies in the fact that my fears are so vague, and my suspicions +depend so entirely upon small points, which might seem trivial to +another, that even he to whom of all others I have a right to +look for help and advice looks upon all that I tell him about it +as the fancies of a nervous woman. He does not say so, but I can +read it from his soothing answers and averted eyes. But I have +heard, Mr. Holmes, that you can see deeply into the manifold +wickedness of the human heart. You may advise me how to walk amid +the dangers which encompass me." + +"I am all attention, madam." + +"My name is Helen Stoner, and I am living with my stepfather, who +is the last survivor of one of the oldest Saxon families in +England, the Roylotts of Stoke Moran, on the western border of +Surrey." + +Holmes nodded his head. "The name is familiar to me," said he. + +"The family was at one time among the richest in England, and the +estates extended over the borders into Berkshire in the north, +and Hampshire in the west. In the last century, however, four +successive heirs were of a dissolute and wasteful disposition, +and the family ruin was eventually completed by a gambler in the +days of the Regency. Nothing was left save a few acres of ground, +and the two-hundred-year-old house, which is itself crushed under +a heavy mortgage. The last squire dragged out his existence +there, living the horrible life of an aristocratic pauper; but +his only son, my stepfather, seeing that he must adapt himself to +the new conditions, obtained an advance from a relative, which +enabled him to take a medical degree and went out to Calcutta, +where, by his professional skill and his force of character, he +established a large practice. In a fit of anger, however, caused +by some robberies which had been perpetrated in the house, he +beat his native butler to death and narrowly escaped a capital +sentence. As it was, he suffered a long term of imprisonment and +afterwards returned to England a morose and disappointed man. + +"When Dr. Roylott was in India he married my mother, Mrs. Stoner, +the young widow of Major-General Stoner, of the Bengal Artillery. +My sister Julia and I were twins, and we were only two years old +at the time of my mother's re-marriage. She had a considerable +sum of money--not less than 1000 pounds a year--and this she +bequeathed to Dr. Roylott entirely while we resided with him, +with a provision that a certain annual sum should be allowed to +each of us in the event of our marriage. Shortly after our return +to England my mother died--she was killed eight years ago in a +railway accident near Crewe. Dr. Roylott then abandoned his +attempts to establish himself in practice in London and took us +to live with him in the old ancestral house at Stoke Moran. The +money which my mother had left was enough for all our wants, and +there seemed to be no obstacle to our happiness. + +"But a terrible change came over our stepfather about this time. +Instead of making friends and exchanging visits with our +neighbours, who had at first been overjoyed to see a Roylott of +Stoke Moran back in the old family seat, he shut himself up in +his house and seldom came out save to indulge in ferocious +quarrels with whoever might cross his path. Violence of temper +approaching to mania has been hereditary in the men of the +family, and in my stepfather's case it had, I believe, been +intensified by his long residence in the tropics. A series of +disgraceful brawls took place, two of which ended in the +police-court, until at last he became the terror of the village, +and the folks would fly at his approach, for he is a man of +immense strength, and absolutely uncontrollable in his anger. + +"Last week he hurled the local blacksmith over a parapet into a +stream, and it was only by paying over all the money which I +could gather together that I was able to avert another public +exposure. He had no friends at all save the wandering gipsies, +and he would give these vagabonds leave to encamp upon the few +acres of bramble-covered land which represent the family estate, +and would accept in return the hospitality of their tents, +wandering away with them sometimes for weeks on end. He has a +passion also for Indian animals, which are sent over to him by a +correspondent, and he has at this moment a cheetah and a baboon, +which wander freely over his grounds and are feared by the +villagers almost as much as their master. + +"You can imagine from what I say that my poor sister Julia and I +had no great pleasure in our lives. No servant would stay with +us, and for a long time we did all the work of the house. She was +but thirty at the time of her death, and yet her hair had already +begun to whiten, even as mine has." + +"Your sister is dead, then?" + +"She died just two years ago, and it is of her death that I wish +to speak to you. You can understand that, living the life which I +have described, we were little likely to see anyone of our own +age and position. We had, however, an aunt, my mother's maiden +sister, Miss Honoria Westphail, who lives near Harrow, and we +were occasionally allowed to pay short visits at this lady's +house. Julia went there at Christmas two years ago, and met there +a half-pay major of marines, to whom she became engaged. My +stepfather learned of the engagement when my sister returned and +offered no objection to the marriage; but within a fortnight of +the day which had been fixed for the wedding, the terrible event +occurred which has deprived me of my only companion." + +Sherlock Holmes had been leaning back in his chair with his eyes +closed and his head sunk in a cushion, but he half opened his +lids now and glanced across at his visitor. + +"Pray be precise as to details," said he. + +"It is easy for me to be so, for every event of that dreadful +time is seared into my memory. The manor-house is, as I have +already said, very old, and only one wing is now inhabited. The +bedrooms in this wing are on the ground floor, the sitting-rooms +being in the central block of the buildings. Of these bedrooms +the first is Dr. Roylott's, the second my sister's, and the third +my own. There is no communication between them, but they all open +out into the same corridor. Do I make myself plain?" + +"Perfectly so." + +"The windows of the three rooms open out upon the lawn. That +fatal night Dr. Roylott had gone to his room early, though we +knew that he had not retired to rest, for my sister was troubled +by the smell of the strong Indian cigars which it was his custom +to smoke. She left her room, therefore, and came into mine, where +she sat for some time, chatting about her approaching wedding. At +eleven o'clock she rose to leave me, but she paused at the door +and looked back. + +"'Tell me, Helen,' said she, 'have you ever heard anyone whistle +in the dead of the night?' + +"'Never,' said I. + +"'I suppose that you could not possibly whistle, yourself, in +your sleep?' + +"'Certainly not. But why?' + +"'Because during the last few nights I have always, about three +in the morning, heard a low, clear whistle. I am a light sleeper, +and it has awakened me. I cannot tell where it came from--perhaps +from the next room, perhaps from the lawn. I thought that I would +just ask you whether you had heard it.' + +"'No, I have not. It must be those wretched gipsies in the +plantation.' + +"'Very likely. And yet if it were on the lawn, I wonder that you +did not hear it also.' + +"'Ah, but I sleep more heavily than you.' + +"'Well, it is of no great consequence, at any rate.' She smiled +back at me, closed my door, and a few moments later I heard her +key turn in the lock." + +"Indeed," said Holmes. "Was it your custom always to lock +yourselves in at night?" + +"Always." + +"And why?" + +"I think that I mentioned to you that the doctor kept a cheetah +and a baboon. We had no feeling of security unless our doors were +locked." + +"Quite so. Pray proceed with your statement." + +"I could not sleep that night. A vague feeling of impending +misfortune impressed me. My sister and I, you will recollect, +were twins, and you know how subtle are the links which bind two +souls which are so closely allied. It was a wild night. The wind +was howling outside, and the rain was beating and splashing +against the windows. Suddenly, amid all the hubbub of the gale, +there burst forth the wild scream of a terrified woman. I knew +that it was my sister's voice. I sprang from my bed, wrapped a +shawl round me, and rushed into the corridor. As I opened my door +I seemed to hear a low whistle, such as my sister described, and +a few moments later a clanging sound, as if a mass of metal had +fallen. As I ran down the passage, my sister's door was unlocked, +and revolved slowly upon its hinges. I stared at it +horror-stricken, not knowing what was about to issue from it. By +the light of the corridor-lamp I saw my sister appear at the +opening, her face blanched with terror, her hands groping for +help, her whole figure swaying to and fro like that of a +drunkard. I ran to her and threw my arms round her, but at that +moment her knees seemed to give way and she fell to the ground. +She writhed as one who is in terrible pain, and her limbs were +dreadfully convulsed. At first I thought that she had not +recognised me, but as I bent over her she suddenly shrieked out +in a voice which I shall never forget, 'Oh, my God! Helen! It was +the band! The speckled band!' There was something else which she +would fain have said, and she stabbed with her finger into the +air in the direction of the doctor's room, but a fresh convulsion +seized her and choked her words. I rushed out, calling loudly for +my stepfather, and I met him hastening from his room in his +dressing-gown. When he reached my sister's side she was +unconscious, and though he poured brandy down her throat and sent +for medical aid from the village, all efforts were in vain, for +she slowly sank and died without having recovered her +consciousness. Such was the dreadful end of my beloved sister." + +"One moment," said Holmes, "are you sure about this whistle and +metallic sound? Could you swear to it?" + +"That was what the county coroner asked me at the inquiry. It is +my strong impression that I heard it, and yet, among the crash of +the gale and the creaking of an old house, I may possibly have +been deceived." + +"Was your sister dressed?" + +"No, she was in her night-dress. In her right hand was found the +charred stump of a match, and in her left a match-box." + +"Showing that she had struck a light and looked about her when +the alarm took place. That is important. And what conclusions did +the coroner come to?" + +"He investigated the case with great care, for Dr. Roylott's +conduct had long been notorious in the county, but he was unable +to find any satisfactory cause of death. My evidence showed that +the door had been fastened upon the inner side, and the windows +were blocked by old-fashioned shutters with broad iron bars, +which were secured every night. The walls were carefully sounded, +and were shown to be quite solid all round, and the flooring was +also thoroughly examined, with the same result. The chimney is +wide, but is barred up by four large staples. It is certain, +therefore, that my sister was quite alone when she met her end. +Besides, there were no marks of any violence upon her." + +"How about poison?" + +"The doctors examined her for it, but without success." + +"What do you think that this unfortunate lady died of, then?" + +"It is my belief that she died of pure fear and nervous shock, +though what it was that frightened her I cannot imagine." + +"Were there gipsies in the plantation at the time?" + +"Yes, there are nearly always some there." + +"Ah, and what did you gather from this allusion to a band--a +speckled band?" + +"Sometimes I have thought that it was merely the wild talk of +delirium, sometimes that it may have referred to some band of +people, perhaps to these very gipsies in the plantation. I do not +know whether the spotted handkerchiefs which so many of them wear +over their heads might have suggested the strange adjective which +she used." + +Holmes shook his head like a man who is far from being satisfied. + +"These are very deep waters," said he; "pray go on with your +narrative." + +"Two years have passed since then, and my life has been until +lately lonelier than ever. A month ago, however, a dear friend, +whom I have known for many years, has done me the honour to ask +my hand in marriage. His name is Armitage--Percy Armitage--the +second son of Mr. Armitage, of Crane Water, near Reading. My +stepfather has offered no opposition to the match, and we are to +be married in the course of the spring. Two days ago some repairs +were started in the west wing of the building, and my bedroom +wall has been pierced, so that I have had to move into the +chamber in which my sister died, and to sleep in the very bed in +which she slept. Imagine, then, my thrill of terror when last +night, as I lay awake, thinking over her terrible fate, I +suddenly heard in the silence of the night the low whistle which +had been the herald of her own death. I sprang up and lit the +lamp, but nothing was to be seen in the room. I was too shaken to +go to bed again, however, so I dressed, and as soon as it was +daylight I slipped down, got a dog-cart at the Crown Inn, which +is opposite, and drove to Leatherhead, from whence I have come on +this morning with the one object of seeing you and asking your +advice." + +"You have done wisely," said my friend. "But have you told me +all?" + +"Yes, all." + +"Miss Roylott, you have not. You are screening your stepfather." + +"Why, what do you mean?" + +For answer Holmes pushed back the frill of black lace which +fringed the hand that lay upon our visitor's knee. Five little +livid spots, the marks of four fingers and a thumb, were printed +upon the white wrist. + +"You have been cruelly used," said Holmes. + +The lady coloured deeply and covered over her injured wrist. "He +is a hard man," she said, "and perhaps he hardly knows his own +strength." + +There was a long silence, during which Holmes leaned his chin +upon his hands and stared into the crackling fire. + +"This is a very deep business," he said at last. "There are a +thousand details which I should desire to know before I decide +upon our course of action. Yet we have not a moment to lose. If +we were to come to Stoke Moran to-day, would it be possible for +us to see over these rooms without the knowledge of your +stepfather?" + +"As it happens, he spoke of coming into town to-day upon some +most important business. It is probable that he will be away all +day, and that there would be nothing to disturb you. We have a +housekeeper now, but she is old and foolish, and I could easily +get her out of the way." + +"Excellent. You are not averse to this trip, Watson?" + +"By no means." + +"Then we shall both come. What are you going to do yourself?" + +"I have one or two things which I would wish to do now that I am +in town. But I shall return by the twelve o'clock train, so as to +be there in time for your coming." + +"And you may expect us early in the afternoon. I have myself some +small business matters to attend to. Will you not wait and +breakfast?" + +"No, I must go. My heart is lightened already since I have +confided my trouble to you. I shall look forward to seeing you +again this afternoon." She dropped her thick black veil over her +face and glided from the room. + +"And what do you think of it all, Watson?" asked Sherlock Holmes, +leaning back in his chair. + +"It seems to me to be a most dark and sinister business." + +"Dark enough and sinister enough." + +"Yet if the lady is correct in saying that the flooring and walls +are sound, and that the door, window, and chimney are impassable, +then her sister must have been undoubtedly alone when she met her +mysterious end." + +"What becomes, then, of these nocturnal whistles, and what of the +very peculiar words of the dying woman?" + +"I cannot think." + +"When you combine the ideas of whistles at night, the presence of +a band of gipsies who are on intimate terms with this old doctor, +the fact that we have every reason to believe that the doctor has +an interest in preventing his stepdaughter's marriage, the dying +allusion to a band, and, finally, the fact that Miss Helen Stoner +heard a metallic clang, which might have been caused by one of +those metal bars that secured the shutters falling back into its +place, I think that there is good ground to think that the +mystery may be cleared along those lines." + +"But what, then, did the gipsies do?" + +"I cannot imagine." + +"I see many objections to any such theory." + +"And so do I. It is precisely for that reason that we are going +to Stoke Moran this day. I want to see whether the objections are +fatal, or if they may be explained away. But what in the name of +the devil!" + +The ejaculation had been drawn from my companion by the fact that +our door had been suddenly dashed open, and that a huge man had +framed himself in the aperture. His costume was a peculiar +mixture of the professional and of the agricultural, having a +black top-hat, a long frock-coat, and a pair of high gaiters, +with a hunting-crop swinging in his hand. So tall was he that his +hat actually brushed the cross bar of the doorway, and his +breadth seemed to span it across from side to side. A large face, +seared with a thousand wrinkles, burned yellow with the sun, and +marked with every evil passion, was turned from one to the other +of us, while his deep-set, bile-shot eyes, and his high, thin, +fleshless nose, gave him somewhat the resemblance to a fierce old +bird of prey. + +"Which of you is Holmes?" asked this apparition. + +"My name, sir; but you have the advantage of me," said my +companion quietly. + +"I am Dr. Grimesby Roylott, of Stoke Moran." + +"Indeed, Doctor," said Holmes blandly. "Pray take a seat." + +"I will do nothing of the kind. My stepdaughter has been here. I +have traced her. What has she been saying to you?" + +"It is a little cold for the time of the year," said Holmes. + +"What has she been saying to you?" screamed the old man +furiously. + +"But I have heard that the crocuses promise well," continued my +companion imperturbably. + +"Ha! You put me off, do you?" said our new visitor, taking a step +forward and shaking his hunting-crop. "I know you, you scoundrel! +I have heard of you before. You are Holmes, the meddler." + +My friend smiled. + +"Holmes, the busybody!" + +His smile broadened. + +"Holmes, the Scotland Yard Jack-in-office!" + +Holmes chuckled heartily. "Your conversation is most +entertaining," said he. "When you go out close the door, for +there is a decided draught." + +"I will go when I have said my say. Don't you dare to meddle with +my affairs. I know that Miss Stoner has been here. I traced her! +I am a dangerous man to fall foul of! See here." He stepped +swiftly forward, seized the poker, and bent it into a curve with +his huge brown hands. + +"See that you keep yourself out of my grip," he snarled, and +hurling the twisted poker into the fireplace he strode out of the +room. + +"He seems a very amiable person," said Holmes, laughing. "I am +not quite so bulky, but if he had remained I might have shown him +that my grip was not much more feeble than his own." As he spoke +he picked up the steel poker and, with a sudden effort, +straightened it out again. + +"Fancy his having the insolence to confound me with the official +detective force! This incident gives zest to our investigation, +however, and I only trust that our little friend will not suffer +from her imprudence in allowing this brute to trace her. And now, +Watson, we shall order breakfast, and afterwards I shall walk +down to Doctors' Commons, where I hope to get some data which may +help us in this matter." + + +It was nearly one o'clock when Sherlock Holmes returned from his +excursion. He held in his hand a sheet of blue paper, scrawled +over with notes and figures. + +"I have seen the will of the deceased wife," said he. "To +determine its exact meaning I have been obliged to work out the +present prices of the investments with which it is concerned. The +total income, which at the time of the wife's death was little +short of 1100 pounds, is now, through the fall in agricultural +prices, not more than 750 pounds. Each daughter can claim an +income of 250 pounds, in case of marriage. It is evident, +therefore, that if both girls had married, this beauty would have +had a mere pittance, while even one of them would cripple him to +a very serious extent. My morning's work has not been wasted, +since it has proved that he has the very strongest motives for +standing in the way of anything of the sort. And now, Watson, +this is too serious for dawdling, especially as the old man is +aware that we are interesting ourselves in his affairs; so if you +are ready, we shall call a cab and drive to Waterloo. I should be +very much obliged if you would slip your revolver into your +pocket. An Eley's No. 2 is an excellent argument with gentlemen +who can twist steel pokers into knots. That and a tooth-brush +are, I think, all that we need." + +At Waterloo we were fortunate in catching a train for +Leatherhead, where we hired a trap at the station inn and drove +for four or five miles through the lovely Surrey lanes. It was a +perfect day, with a bright sun and a few fleecy clouds in the +heavens. The trees and wayside hedges were just throwing out +their first green shoots, and the air was full of the pleasant +smell of the moist earth. To me at least there was a strange +contrast between the sweet promise of the spring and this +sinister quest upon which we were engaged. My companion sat in +the front of the trap, his arms folded, his hat pulled down over +his eyes, and his chin sunk upon his breast, buried in the +deepest thought. Suddenly, however, he started, tapped me on the +shoulder, and pointed over the meadows. + +"Look there!" said he. + +A heavily timbered park stretched up in a gentle slope, +thickening into a grove at the highest point. From amid the +branches there jutted out the grey gables and high roof-tree of a +very old mansion. + +"Stoke Moran?" said he. + +"Yes, sir, that be the house of Dr. Grimesby Roylott," remarked +the driver. + +"There is some building going on there," said Holmes; "that is +where we are going." + +"There's the village," said the driver, pointing to a cluster of +roofs some distance to the left; "but if you want to get to the +house, you'll find it shorter to get over this stile, and so by +the foot-path over the fields. There it is, where the lady is +walking." + +"And the lady, I fancy, is Miss Stoner," observed Holmes, shading +his eyes. "Yes, I think we had better do as you suggest." + +We got off, paid our fare, and the trap rattled back on its way +to Leatherhead. + +"I thought it as well," said Holmes as we climbed the stile, +"that this fellow should think we had come here as architects, or +on some definite business. It may stop his gossip. +Good-afternoon, Miss Stoner. You see that we have been as good as +our word." + +Our client of the morning had hurried forward to meet us with a +face which spoke her joy. "I have been waiting so eagerly for +you," she cried, shaking hands with us warmly. "All has turned +out splendidly. Dr. Roylott has gone to town, and it is unlikely +that he will be back before evening." + +"We have had the pleasure of making the doctor's acquaintance," +said Holmes, and in a few words he sketched out what had +occurred. Miss Stoner turned white to the lips as she listened. + +"Good heavens!" she cried, "he has followed me, then." + +"So it appears." + +"He is so cunning that I never know when I am safe from him. What +will he say when he returns?" + +"He must guard himself, for he may find that there is someone +more cunning than himself upon his track. You must lock yourself +up from him to-night. If he is violent, we shall take you away to +your aunt's at Harrow. Now, we must make the best use of our +time, so kindly take us at once to the rooms which we are to +examine." + +The building was of grey, lichen-blotched stone, with a high +central portion and two curving wings, like the claws of a crab, +thrown out on each side. In one of these wings the windows were +broken and blocked with wooden boards, while the roof was partly +caved in, a picture of ruin. The central portion was in little +better repair, but the right-hand block was comparatively modern, +and the blinds in the windows, with the blue smoke curling up +from the chimneys, showed that this was where the family resided. +Some scaffolding had been erected against the end wall, and the +stone-work had been broken into, but there were no signs of any +workmen at the moment of our visit. Holmes walked slowly up and +down the ill-trimmed lawn and examined with deep attention the +outsides of the windows. + +"This, I take it, belongs to the room in which you used to sleep, +the centre one to your sister's, and the one next to the main +building to Dr. Roylott's chamber?" + +"Exactly so. But I am now sleeping in the middle one." + +"Pending the alterations, as I understand. By the way, there does +not seem to be any very pressing need for repairs at that end +wall." + +"There were none. I believe that it was an excuse to move me from +my room." + +"Ah! that is suggestive. Now, on the other side of this narrow +wing runs the corridor from which these three rooms open. There +are windows in it, of course?" + +"Yes, but very small ones. Too narrow for anyone to pass +through." + +"As you both locked your doors at night, your rooms were +unapproachable from that side. Now, would you have the kindness +to go into your room and bar your shutters?" + +Miss Stoner did so, and Holmes, after a careful examination +through the open window, endeavoured in every way to force the +shutter open, but without success. There was no slit through +which a knife could be passed to raise the bar. Then with his +lens he tested the hinges, but they were of solid iron, built +firmly into the massive masonry. "Hum!" said he, scratching his +chin in some perplexity, "my theory certainly presents some +difficulties. No one could pass these shutters if they were +bolted. Well, we shall see if the inside throws any light upon +the matter." + +A small side door led into the whitewashed corridor from which +the three bedrooms opened. Holmes refused to examine the third +chamber, so we passed at once to the second, that in which Miss +Stoner was now sleeping, and in which her sister had met with her +fate. It was a homely little room, with a low ceiling and a +gaping fireplace, after the fashion of old country-houses. A +brown chest of drawers stood in one corner, a narrow +white-counterpaned bed in another, and a dressing-table on the +left-hand side of the window. These articles, with two small +wicker-work chairs, made up all the furniture in the room save +for a square of Wilton carpet in the centre. The boards round and +the panelling of the walls were of brown, worm-eaten oak, so old +and discoloured that it may have dated from the original building +of the house. Holmes drew one of the chairs into a corner and sat +silent, while his eyes travelled round and round and up and down, +taking in every detail of the apartment. + +"Where does that bell communicate with?" he asked at last +pointing to a thick bell-rope which hung down beside the bed, the +tassel actually lying upon the pillow. + +"It goes to the housekeeper's room." + +"It looks newer than the other things?" + +"Yes, it was only put there a couple of years ago." + +"Your sister asked for it, I suppose?" + +"No, I never heard of her using it. We used always to get what we +wanted for ourselves." + +"Indeed, it seemed unnecessary to put so nice a bell-pull there. +You will excuse me for a few minutes while I satisfy myself as to +this floor." He threw himself down upon his face with his lens in +his hand and crawled swiftly backward and forward, examining +minutely the cracks between the boards. Then he did the same with +the wood-work with which the chamber was panelled. Finally he +walked over to the bed and spent some time in staring at it and +in running his eye up and down the wall. Finally he took the +bell-rope in his hand and gave it a brisk tug. + +"Why, it's a dummy," said he. + +"Won't it ring?" + +"No, it is not even attached to a wire. This is very interesting. +You can see now that it is fastened to a hook just above where +the little opening for the ventilator is." + +"How very absurd! I never noticed that before." + +"Very strange!" muttered Holmes, pulling at the rope. "There are +one or two very singular points about this room. For example, +what a fool a builder must be to open a ventilator into another +room, when, with the same trouble, he might have communicated +with the outside air!" + +"That is also quite modern," said the lady. + +"Done about the same time as the bell-rope?" remarked Holmes. + +"Yes, there were several little changes carried out about that +time." + +"They seem to have been of a most interesting character--dummy +bell-ropes, and ventilators which do not ventilate. With your +permission, Miss Stoner, we shall now carry our researches into +the inner apartment." + +Dr. Grimesby Roylott's chamber was larger than that of his +step-daughter, but was as plainly furnished. A camp-bed, a small +wooden shelf full of books, mostly of a technical character, an +armchair beside the bed, a plain wooden chair against the wall, a +round table, and a large iron safe were the principal things +which met the eye. Holmes walked slowly round and examined each +and all of them with the keenest interest. + +"What's in here?" he asked, tapping the safe. + +"My stepfather's business papers." + +"Oh! you have seen inside, then?" + +"Only once, some years ago. I remember that it was full of +papers." + +"There isn't a cat in it, for example?" + +"No. What a strange idea!" + +"Well, look at this!" He took up a small saucer of milk which +stood on the top of it. + +"No; we don't keep a cat. But there is a cheetah and a baboon." + +"Ah, yes, of course! Well, a cheetah is just a big cat, and yet a +saucer of milk does not go very far in satisfying its wants, I +daresay. There is one point which I should wish to determine." He +squatted down in front of the wooden chair and examined the seat +of it with the greatest attention. + +"Thank you. That is quite settled," said he, rising and putting +his lens in his pocket. "Hullo! Here is something interesting!" + +The object which had caught his eye was a small dog lash hung on +one corner of the bed. The lash, however, was curled upon itself +and tied so as to make a loop of whipcord. + +"What do you make of that, Watson?" + +"It's a common enough lash. But I don't know why it should be +tied." + +"That is not quite so common, is it? Ah, me! it's a wicked world, +and when a clever man turns his brains to crime it is the worst +of all. I think that I have seen enough now, Miss Stoner, and +with your permission we shall walk out upon the lawn." + +I had never seen my friend's face so grim or his brow so dark as +it was when we turned from the scene of this investigation. We +had walked several times up and down the lawn, neither Miss +Stoner nor myself liking to break in upon his thoughts before he +roused himself from his reverie. + +"It is very essential, Miss Stoner," said he, "that you should +absolutely follow my advice in every respect." + +"I shall most certainly do so." + +"The matter is too serious for any hesitation. Your life may +depend upon your compliance." + +"I assure you that I am in your hands." + +"In the first place, both my friend and I must spend the night in +your room." + +Both Miss Stoner and I gazed at him in astonishment. + +"Yes, it must be so. Let me explain. I believe that that is the +village inn over there?" + +"Yes, that is the Crown." + +"Very good. Your windows would be visible from there?" + +"Certainly." + +"You must confine yourself to your room, on pretence of a +headache, when your stepfather comes back. Then when you hear him +retire for the night, you must open the shutters of your window, +undo the hasp, put your lamp there as a signal to us, and then +withdraw quietly with everything which you are likely to want +into the room which you used to occupy. I have no doubt that, in +spite of the repairs, you could manage there for one night." + +"Oh, yes, easily." + +"The rest you will leave in our hands." + +"But what will you do?" + +"We shall spend the night in your room, and we shall investigate +the cause of this noise which has disturbed you." + +"I believe, Mr. Holmes, that you have already made up your mind," +said Miss Stoner, laying her hand upon my companion's sleeve. + +"Perhaps I have." + +"Then, for pity's sake, tell me what was the cause of my sister's +death." + +"I should prefer to have clearer proofs before I speak." + +"You can at least tell me whether my own thought is correct, and +if she died from some sudden fright." + +"No, I do not think so. I think that there was probably some more +tangible cause. And now, Miss Stoner, we must leave you for if +Dr. Roylott returned and saw us our journey would be in vain. +Good-bye, and be brave, for if you will do what I have told you, +you may rest assured that we shall soon drive away the dangers +that threaten you." + +Sherlock Holmes and I had no difficulty in engaging a bedroom and +sitting-room at the Crown Inn. They were on the upper floor, and +from our window we could command a view of the avenue gate, and +of the inhabited wing of Stoke Moran Manor House. At dusk we saw +Dr. Grimesby Roylott drive past, his huge form looming up beside +the little figure of the lad who drove him. The boy had some +slight difficulty in undoing the heavy iron gates, and we heard +the hoarse roar of the doctor's voice and saw the fury with which +he shook his clinched fists at him. The trap drove on, and a few +minutes later we saw a sudden light spring up among the trees as +the lamp was lit in one of the sitting-rooms. + +"Do you know, Watson," said Holmes as we sat together in the +gathering darkness, "I have really some scruples as to taking you +to-night. There is a distinct element of danger." + +"Can I be of assistance?" + +"Your presence might be invaluable." + +"Then I shall certainly come." + +"It is very kind of you." + +"You speak of danger. You have evidently seen more in these rooms +than was visible to me." + +"No, but I fancy that I may have deduced a little more. I imagine +that you saw all that I did." + +"I saw nothing remarkable save the bell-rope, and what purpose +that could answer I confess is more than I can imagine." + +"You saw the ventilator, too?" + +"Yes, but I do not think that it is such a very unusual thing to +have a small opening between two rooms. It was so small that a +rat could hardly pass through." + +"I knew that we should find a ventilator before ever we came to +Stoke Moran." + +"My dear Holmes!" + +"Oh, yes, I did. You remember in her statement she said that her +sister could smell Dr. Roylott's cigar. Now, of course that +suggested at once that there must be a communication between the +two rooms. It could only be a small one, or it would have been +remarked upon at the coroner's inquiry. I deduced a ventilator." + +"But what harm can there be in that?" + +"Well, there is at least a curious coincidence of dates. A +ventilator is made, a cord is hung, and a lady who sleeps in the +bed dies. Does not that strike you?" + +"I cannot as yet see any connection." + +"Did you observe anything very peculiar about that bed?" + +"No." + +"It was clamped to the floor. Did you ever see a bed fastened +like that before?" + +"I cannot say that I have." + +"The lady could not move her bed. It must always be in the same +relative position to the ventilator and to the rope--or so we may +call it, since it was clearly never meant for a bell-pull." + +"Holmes," I cried, "I seem to see dimly what you are hinting at. +We are only just in time to prevent some subtle and horrible +crime." + +"Subtle enough and horrible enough. When a doctor does go wrong +he is the first of criminals. He has nerve and he has knowledge. +Palmer and Pritchard were among the heads of their profession. +This man strikes even deeper, but I think, Watson, that we shall +be able to strike deeper still. But we shall have horrors enough +before the night is over; for goodness' sake let us have a quiet +pipe and turn our minds for a few hours to something more +cheerful." + + +About nine o'clock the light among the trees was extinguished, +and all was dark in the direction of the Manor House. Two hours +passed slowly away, and then, suddenly, just at the stroke of +eleven, a single bright light shone out right in front of us. + +"That is our signal," said Holmes, springing to his feet; "it +comes from the middle window." + +As we passed out he exchanged a few words with the landlord, +explaining that we were going on a late visit to an acquaintance, +and that it was possible that we might spend the night there. A +moment later we were out on the dark road, a chill wind blowing +in our faces, and one yellow light twinkling in front of us +through the gloom to guide us on our sombre errand. + +There was little difficulty in entering the grounds, for +unrepaired breaches gaped in the old park wall. Making our way +among the trees, we reached the lawn, crossed it, and were about +to enter through the window when out from a clump of laurel +bushes there darted what seemed to be a hideous and distorted +child, who threw itself upon the grass with writhing limbs and +then ran swiftly across the lawn into the darkness. + +"My God!" I whispered; "did you see it?" + +Holmes was for the moment as startled as I. His hand closed like +a vice upon my wrist in his agitation. Then he broke into a low +laugh and put his lips to my ear. + +"It is a nice household," he murmured. "That is the baboon." + +I had forgotten the strange pets which the doctor affected. There +was a cheetah, too; perhaps we might find it upon our shoulders +at any moment. I confess that I felt easier in my mind when, +after following Holmes' example and slipping off my shoes, I +found myself inside the bedroom. My companion noiselessly closed +the shutters, moved the lamp onto the table, and cast his eyes +round the room. All was as we had seen it in the daytime. Then +creeping up to me and making a trumpet of his hand, he whispered +into my ear again so gently that it was all that I could do to +distinguish the words: + +"The least sound would be fatal to our plans." + +I nodded to show that I had heard. + +"We must sit without light. He would see it through the +ventilator." + +I nodded again. + +"Do not go asleep; your very life may depend upon it. Have your +pistol ready in case we should need it. I will sit on the side of +the bed, and you in that chair." + +I took out my revolver and laid it on the corner of the table. + +Holmes had brought up a long thin cane, and this he placed upon +the bed beside him. By it he laid the box of matches and the +stump of a candle. Then he turned down the lamp, and we were left +in darkness. + +How shall I ever forget that dreadful vigil? I could not hear a +sound, not even the drawing of a breath, and yet I knew that my +companion sat open-eyed, within a few feet of me, in the same +state of nervous tension in which I was myself. The shutters cut +off the least ray of light, and we waited in absolute darkness. + +From outside came the occasional cry of a night-bird, and once at +our very window a long drawn catlike whine, which told us that +the cheetah was indeed at liberty. Far away we could hear the +deep tones of the parish clock, which boomed out every quarter of +an hour. How long they seemed, those quarters! Twelve struck, and +one and two and three, and still we sat waiting silently for +whatever might befall. + +Suddenly there was the momentary gleam of a light up in the +direction of the ventilator, which vanished immediately, but was +succeeded by a strong smell of burning oil and heated metal. +Someone in the next room had lit a dark-lantern. I heard a gentle +sound of movement, and then all was silent once more, though the +smell grew stronger. For half an hour I sat with straining ears. +Then suddenly another sound became audible--a very gentle, +soothing sound, like that of a small jet of steam escaping +continually from a kettle. The instant that we heard it, Holmes +sprang from the bed, struck a match, and lashed furiously with +his cane at the bell-pull. + +"You see it, Watson?" he yelled. "You see it?" + +But I saw nothing. At the moment when Holmes struck the light I +heard a low, clear whistle, but the sudden glare flashing into my +weary eyes made it impossible for me to tell what it was at which +my friend lashed so savagely. I could, however, see that his face +was deadly pale and filled with horror and loathing. He had +ceased to strike and was gazing up at the ventilator when +suddenly there broke from the silence of the night the most +horrible cry to which I have ever listened. It swelled up louder +and louder, a hoarse yell of pain and fear and anger all mingled +in the one dreadful shriek. They say that away down in the +village, and even in the distant parsonage, that cry raised the +sleepers from their beds. It struck cold to our hearts, and I +stood gazing at Holmes, and he at me, until the last echoes of it +had died away into the silence from which it rose. + +"What can it mean?" I gasped. + +"It means that it is all over," Holmes answered. "And perhaps, +after all, it is for the best. Take your pistol, and we will +enter Dr. Roylott's room." + +With a grave face he lit the lamp and led the way down the +corridor. Twice he struck at the chamber door without any reply +from within. Then he turned the handle and entered, I at his +heels, with the cocked pistol in my hand. + +It was a singular sight which met our eyes. On the table stood a +dark-lantern with the shutter half open, throwing a brilliant +beam of light upon the iron safe, the door of which was ajar. +Beside this table, on the wooden chair, sat Dr. Grimesby Roylott +clad in a long grey dressing-gown, his bare ankles protruding +beneath, and his feet thrust into red heelless Turkish slippers. +Across his lap lay the short stock with the long lash which we +had noticed during the day. His chin was cocked upward and his +eyes were fixed in a dreadful, rigid stare at the corner of the +ceiling. Round his brow he had a peculiar yellow band, with +brownish speckles, which seemed to be bound tightly round his +head. As we entered he made neither sound nor motion. + +"The band! the speckled band!" whispered Holmes. + +I took a step forward. In an instant his strange headgear began +to move, and there reared itself from among his hair the squat +diamond-shaped head and puffed neck of a loathsome serpent. + +"It is a swamp adder!" cried Holmes; "the deadliest snake in +India. He has died within ten seconds of being bitten. Violence +does, in truth, recoil upon the violent, and the schemer falls +into the pit which he digs for another. Let us thrust this +creature back into its den, and we can then remove Miss Stoner to +some place of shelter and let the county police know what has +happened." + +As he spoke he drew the dog-whip swiftly from the dead man's lap, +and throwing the noose round the reptile's neck he drew it from +its horrid perch and, carrying it at arm's length, threw it into +the iron safe, which he closed upon it. + +Such are the true facts of the death of Dr. Grimesby Roylott, of +Stoke Moran. It is not necessary that I should prolong a +narrative which has already run to too great a length by telling +how we broke the sad news to the terrified girl, how we conveyed +her by the morning train to the care of her good aunt at Harrow, +of how the slow process of official inquiry came to the +conclusion that the doctor met his fate while indiscreetly +playing with a dangerous pet. The little which I had yet to learn +of the case was told me by Sherlock Holmes as we travelled back +next day. + +"I had," said he, "come to an entirely erroneous conclusion which +shows, my dear Watson, how dangerous it always is to reason from +insufficient data. The presence of the gipsies, and the use of +the word 'band,' which was used by the poor girl, no doubt, to +explain the appearance which she had caught a hurried glimpse of +by the light of her match, were sufficient to put me upon an +entirely wrong scent. I can only claim the merit that I instantly +reconsidered my position when, however, it became clear to me +that whatever danger threatened an occupant of the room could not +come either from the window or the door. My attention was +speedily drawn, as I have already remarked to you, to this +ventilator, and to the bell-rope which hung down to the bed. The +discovery that this was a dummy, and that the bed was clamped to +the floor, instantly gave rise to the suspicion that the rope was +there as a bridge for something passing through the hole and +coming to the bed. The idea of a snake instantly occurred to me, +and when I coupled it with my knowledge that the doctor was +furnished with a supply of creatures from India, I felt that I +was probably on the right track. The idea of using a form of +poison which could not possibly be discovered by any chemical +test was just such a one as would occur to a clever and ruthless +man who had had an Eastern training. The rapidity with which such +a poison would take effect would also, from his point of view, be +an advantage. It would be a sharp-eyed coroner, indeed, who could +distinguish the two little dark punctures which would show where +the poison fangs had done their work. Then I thought of the +whistle. Of course he must recall the snake before the morning +light revealed it to the victim. He had trained it, probably by +the use of the milk which we saw, to return to him when summoned. +He would put it through this ventilator at the hour that he +thought best, with the certainty that it would crawl down the +rope and land on the bed. It might or might not bite the +occupant, perhaps she might escape every night for a week, but +sooner or later she must fall a victim. + +"I had come to these conclusions before ever I had entered his +room. An inspection of his chair showed me that he had been in +the habit of standing on it, which of course would be necessary +in order that he should reach the ventilator. The sight of the +safe, the saucer of milk, and the loop of whipcord were enough to +finally dispel any doubts which may have remained. The metallic +clang heard by Miss Stoner was obviously caused by her stepfather +hastily closing the door of his safe upon its terrible occupant. +Having once made up my mind, you know the steps which I took in +order to put the matter to the proof. I heard the creature hiss +as I have no doubt that you did also, and I instantly lit the +light and attacked it." + +"With the result of driving it through the ventilator." + +"And also with the result of causing it to turn upon its master +at the other side. Some of the blows of my cane came home and +roused its snakish temper, so that it flew upon the first person +it saw. In this way I am no doubt indirectly responsible for Dr. +Grimesby Roylott's death, and I cannot say that it is likely to +weigh very heavily upon my conscience." + + + +IX. THE ADVENTURE OF THE ENGINEER'S THUMB + +Of all the problems which have been submitted to my friend, Mr. +Sherlock Holmes, for solution during the years of our intimacy, +there were only two which I was the means of introducing to his +notice--that of Mr. Hatherley's thumb, and that of Colonel +Warburton's madness. Of these the latter may have afforded a +finer field for an acute and original observer, but the other was +so strange in its inception and so dramatic in its details that +it may be the more worthy of being placed upon record, even if it +gave my friend fewer openings for those deductive methods of +reasoning by which he achieved such remarkable results. The story +has, I believe, been told more than once in the newspapers, but, +like all such narratives, its effect is much less striking when +set forth en bloc in a single half-column of print than when the +facts slowly evolve before your own eyes, and the mystery clears +gradually away as each new discovery furnishes a step which leads +on to the complete truth. At the time the circumstances made a +deep impression upon me, and the lapse of two years has hardly +served to weaken the effect. + +It was in the summer of '89, not long after my marriage, that the +events occurred which I am now about to summarise. I had returned +to civil practice and had finally abandoned Holmes in his Baker +Street rooms, although I continually visited him and occasionally +even persuaded him to forgo his Bohemian habits so far as to come +and visit us. My practice had steadily increased, and as I +happened to live at no very great distance from Paddington +Station, I got a few patients from among the officials. One of +these, whom I had cured of a painful and lingering disease, was +never weary of advertising my virtues and of endeavouring to send +me on every sufferer over whom he might have any influence. + +One morning, at a little before seven o'clock, I was awakened by +the maid tapping at the door to announce that two men had come +from Paddington and were waiting in the consulting-room. I +dressed hurriedly, for I knew by experience that railway cases +were seldom trivial, and hastened downstairs. As I descended, my +old ally, the guard, came out of the room and closed the door +tightly behind him. + +"I've got him here," he whispered, jerking his thumb over his +shoulder; "he's all right." + +"What is it, then?" I asked, for his manner suggested that it was +some strange creature which he had caged up in my room. + +"It's a new patient," he whispered. "I thought I'd bring him +round myself; then he couldn't slip away. There he is, all safe +and sound. I must go now, Doctor; I have my dooties, just the +same as you." And off he went, this trusty tout, without even +giving me time to thank him. + +I entered my consulting-room and found a gentleman seated by the +table. He was quietly dressed in a suit of heather tweed with a +soft cloth cap which he had laid down upon my books. Round one of +his hands he had a handkerchief wrapped, which was mottled all +over with bloodstains. He was young, not more than +five-and-twenty, I should say, with a strong, masculine face; but +he was exceedingly pale and gave me the impression of a man who +was suffering from some strong agitation, which it took all his +strength of mind to control. + +"I am sorry to knock you up so early, Doctor," said he, "but I +have had a very serious accident during the night. I came in by +train this morning, and on inquiring at Paddington as to where I +might find a doctor, a worthy fellow very kindly escorted me +here. I gave the maid a card, but I see that she has left it upon +the side-table." + +I took it up and glanced at it. "Mr. Victor Hatherley, hydraulic +engineer, 16A, Victoria Street (3rd floor)." That was the name, +style, and abode of my morning visitor. "I regret that I have +kept you waiting," said I, sitting down in my library-chair. "You +are fresh from a night journey, I understand, which is in itself +a monotonous occupation." + +"Oh, my night could not be called monotonous," said he, and +laughed. He laughed very heartily, with a high, ringing note, +leaning back in his chair and shaking his sides. All my medical +instincts rose up against that laugh. + +"Stop it!" I cried; "pull yourself together!" and I poured out +some water from a caraffe. + +It was useless, however. He was off in one of those hysterical +outbursts which come upon a strong nature when some great crisis +is over and gone. Presently he came to himself once more, very +weary and pale-looking. + +"I have been making a fool of myself," he gasped. + +"Not at all. Drink this." I dashed some brandy into the water, +and the colour began to come back to his bloodless cheeks. + +"That's better!" said he. "And now, Doctor, perhaps you would +kindly attend to my thumb, or rather to the place where my thumb +used to be." + +He unwound the handkerchief and held out his hand. It gave even +my hardened nerves a shudder to look at it. There were four +protruding fingers and a horrid red, spongy surface where the +thumb should have been. It had been hacked or torn right out from +the roots. + +"Good heavens!" I cried, "this is a terrible injury. It must have +bled considerably." + +"Yes, it did. I fainted when it was done, and I think that I must +have been senseless for a long time. When I came to I found that +it was still bleeding, so I tied one end of my handkerchief very +tightly round the wrist and braced it up with a twig." + +"Excellent! You should have been a surgeon." + +"It is a question of hydraulics, you see, and came within my own +province." + +"This has been done," said I, examining the wound, "by a very +heavy and sharp instrument." + +"A thing like a cleaver," said he. + +"An accident, I presume?" + +"By no means." + +"What! a murderous attack?" + +"Very murderous indeed." + +"You horrify me." + +I sponged the wound, cleaned it, dressed it, and finally covered +it over with cotton wadding and carbolised bandages. He lay back +without wincing, though he bit his lip from time to time. + +"How is that?" I asked when I had finished. + +"Capital! Between your brandy and your bandage, I feel a new man. +I was very weak, but I have had a good deal to go through." + +"Perhaps you had better not speak of the matter. It is evidently +trying to your nerves." + +"Oh, no, not now. I shall have to tell my tale to the police; +but, between ourselves, if it were not for the convincing +evidence of this wound of mine, I should be surprised if they +believed my statement, for it is a very extraordinary one, and I +have not much in the way of proof with which to back it up; and, +even if they believe me, the clues which I can give them are so +vague that it is a question whether justice will be done." + +"Ha!" cried I, "if it is anything in the nature of a problem +which you desire to see solved, I should strongly recommend you +to come to my friend, Mr. Sherlock Holmes, before you go to the +official police." + +"Oh, I have heard of that fellow," answered my visitor, "and I +should be very glad if he would take the matter up, though of +course I must use the official police as well. Would you give me +an introduction to him?" + +"I'll do better. I'll take you round to him myself." + +"I should be immensely obliged to you." + +"We'll call a cab and go together. We shall just be in time to +have a little breakfast with him. Do you feel equal to it?" + +"Yes; I shall not feel easy until I have told my story." + +"Then my servant will call a cab, and I shall be with you in an +instant." I rushed upstairs, explained the matter shortly to my +wife, and in five minutes was inside a hansom, driving with my +new acquaintance to Baker Street. + +Sherlock Holmes was, as I expected, lounging about his +sitting-room in his dressing-gown, reading the agony column of The +Times and smoking his before-breakfast pipe, which was composed +of all the plugs and dottles left from his smokes of the day +before, all carefully dried and collected on the corner of the +mantelpiece. He received us in his quietly genial fashion, +ordered fresh rashers and eggs, and joined us in a hearty meal. +When it was concluded he settled our new acquaintance upon the +sofa, placed a pillow beneath his head, and laid a glass of +brandy and water within his reach. + +"It is easy to see that your experience has been no common one, +Mr. Hatherley," said he. "Pray, lie down there and make yourself +absolutely at home. Tell us what you can, but stop when you are +tired and keep up your strength with a little stimulant." + +"Thank you," said my patient, "but I have felt another man since +the doctor bandaged me, and I think that your breakfast has +completed the cure. I shall take up as little of your valuable +time as possible, so I shall start at once upon my peculiar +experiences." + +Holmes sat in his big armchair with the weary, heavy-lidded +expression which veiled his keen and eager nature, while I sat +opposite to him, and we listened in silence to the strange story +which our visitor detailed to us. + +"You must know," said he, "that I am an orphan and a bachelor, +residing alone in lodgings in London. By profession I am a +hydraulic engineer, and I have had considerable experience of my +work during the seven years that I was apprenticed to Venner & +Matheson, the well-known firm, of Greenwich. Two years ago, +having served my time, and having also come into a fair sum of +money through my poor father's death, I determined to start in +business for myself and took professional chambers in Victoria +Street. + +"I suppose that everyone finds his first independent start in +business a dreary experience. To me it has been exceptionally so. +During two years I have had three consultations and one small +job, and that is absolutely all that my profession has brought +me. My gross takings amount to 27 pounds 10s. Every day, from +nine in the morning until four in the afternoon, I waited in my +little den, until at last my heart began to sink, and I came to +believe that I should never have any practice at all. + +"Yesterday, however, just as I was thinking of leaving the +office, my clerk entered to say there was a gentleman waiting who +wished to see me upon business. He brought up a card, too, with +the name of 'Colonel Lysander Stark' engraved upon it. Close at +his heels came the colonel himself, a man rather over the middle +size, but of an exceeding thinness. I do not think that I have +ever seen so thin a man. His whole face sharpened away into nose +and chin, and the skin of his cheeks was drawn quite tense over +his outstanding bones. Yet this emaciation seemed to be his +natural habit, and due to no disease, for his eye was bright, his +step brisk, and his bearing assured. He was plainly but neatly +dressed, and his age, I should judge, would be nearer forty than +thirty. + +"'Mr. Hatherley?' said he, with something of a German accent. +'You have been recommended to me, Mr. Hatherley, as being a man +who is not only proficient in his profession but is also discreet +and capable of preserving a secret.' + +"I bowed, feeling as flattered as any young man would at such an +address. 'May I ask who it was who gave me so good a character?' + +"'Well, perhaps it is better that I should not tell you that just +at this moment. I have it from the same source that you are both +an orphan and a bachelor and are residing alone in London.' + +"'That is quite correct,' I answered; 'but you will excuse me if +I say that I cannot see how all this bears upon my professional +qualifications. I understand that it was on a professional matter +that you wished to speak to me?' + +"'Undoubtedly so. But you will find that all I say is really to +the point. I have a professional commission for you, but absolute +secrecy is quite essential--absolute secrecy, you understand, and +of course we may expect that more from a man who is alone than +from one who lives in the bosom of his family.' + +"'If I promise to keep a secret,' said I, 'you may absolutely +depend upon my doing so.' + +"He looked very hard at me as I spoke, and it seemed to me that I +had never seen so suspicious and questioning an eye. + +"'Do you promise, then?' said he at last. + +"'Yes, I promise.' + +"'Absolute and complete silence before, during, and after? No +reference to the matter at all, either in word or writing?' + +"'I have already given you my word.' + +"'Very good.' He suddenly sprang up, and darting like lightning +across the room he flung open the door. The passage outside was +empty. + +"'That's all right,' said he, coming back. 'I know that clerks are +sometimes curious as to their master's affairs. Now we can talk +in safety.' He drew up his chair very close to mine and began to +stare at me again with the same questioning and thoughtful look. + +"A feeling of repulsion, and of something akin to fear had begun +to rise within me at the strange antics of this fleshless man. +Even my dread of losing a client could not restrain me from +showing my impatience. + +"'I beg that you will state your business, sir,' said I; 'my time +is of value.' Heaven forgive me for that last sentence, but the +words came to my lips. + +"'How would fifty guineas for a night's work suit you?' he asked. + +"'Most admirably.' + +"'I say a night's work, but an hour's would be nearer the mark. I +simply want your opinion about a hydraulic stamping machine which +has got out of gear. If you show us what is wrong we shall soon +set it right ourselves. What do you think of such a commission as +that?' + +"'The work appears to be light and the pay munificent.' + +"'Precisely so. We shall want you to come to-night by the last +train.' + +"'Where to?' + +"'To Eyford, in Berkshire. It is a little place near the borders +of Oxfordshire, and within seven miles of Reading. There is a +train from Paddington which would bring you there at about +11:15.' + +"'Very good.' + +"'I shall come down in a carriage to meet you.' + +"'There is a drive, then?' + +"'Yes, our little place is quite out in the country. It is a good +seven miles from Eyford Station.' + +"'Then we can hardly get there before midnight. I suppose there +would be no chance of a train back. I should be compelled to stop +the night.' + +"'Yes, we could easily give you a shake-down.' + +"'That is very awkward. Could I not come at some more convenient +hour?' + +"'We have judged it best that you should come late. It is to +recompense you for any inconvenience that we are paying to you, a +young and unknown man, a fee which would buy an opinion from the +very heads of your profession. Still, of course, if you would +like to draw out of the business, there is plenty of time to do +so.' + +"I thought of the fifty guineas, and of how very useful they +would be to me. 'Not at all,' said I, 'I shall be very happy to +accommodate myself to your wishes. I should like, however, to +understand a little more clearly what it is that you wish me to +do.' + +"'Quite so. It is very natural that the pledge of secrecy which +we have exacted from you should have aroused your curiosity. I +have no wish to commit you to anything without your having it all +laid before you. I suppose that we are absolutely safe from +eavesdroppers?' + +"'Entirely.' + +"'Then the matter stands thus. You are probably aware that +fuller's-earth is a valuable product, and that it is only found +in one or two places in England?' + +"'I have heard so.' + +"'Some little time ago I bought a small place--a very small +place--within ten miles of Reading. I was fortunate enough to +discover that there was a deposit of fuller's-earth in one of my +fields. On examining it, however, I found that this deposit was a +comparatively small one, and that it formed a link between two +very much larger ones upon the right and left--both of them, +however, in the grounds of my neighbours. These good people were +absolutely ignorant that their land contained that which was +quite as valuable as a gold-mine. Naturally, it was to my +interest to buy their land before they discovered its true value, +but unfortunately I had no capital by which I could do this. I +took a few of my friends into the secret, however, and they +suggested that we should quietly and secretly work our own little +deposit and that in this way we should earn the money which would +enable us to buy the neighbouring fields. This we have now been +doing for some time, and in order to help us in our operations we +erected a hydraulic press. This press, as I have already +explained, has got out of order, and we wish your advice upon the +subject. We guard our secret very jealously, however, and if it +once became known that we had hydraulic engineers coming to our +little house, it would soon rouse inquiry, and then, if the facts +came out, it would be good-bye to any chance of getting these +fields and carrying out our plans. That is why I have made you +promise me that you will not tell a human being that you are +going to Eyford to-night. I hope that I make it all plain?' + +"'I quite follow you,' said I. 'The only point which I could not +quite understand was what use you could make of a hydraulic press +in excavating fuller's-earth, which, as I understand, is dug out +like gravel from a pit.' + +"'Ah!' said he carelessly, 'we have our own process. We compress +the earth into bricks, so as to remove them without revealing +what they are. But that is a mere detail. I have taken you fully +into my confidence now, Mr. Hatherley, and I have shown you how I +trust you.' He rose as he spoke. 'I shall expect you, then, at +Eyford at 11:15.' + +"'I shall certainly be there.' + +"'And not a word to a soul.' He looked at me with a last long, +questioning gaze, and then, pressing my hand in a cold, dank +grasp, he hurried from the room. + +"Well, when I came to think it all over in cool blood I was very +much astonished, as you may both think, at this sudden commission +which had been intrusted to me. On the one hand, of course, I was +glad, for the fee was at least tenfold what I should have asked +had I set a price upon my own services, and it was possible that +this order might lead to other ones. On the other hand, the face +and manner of my patron had made an unpleasant impression upon +me, and I could not think that his explanation of the +fuller's-earth was sufficient to explain the necessity for my +coming at midnight, and his extreme anxiety lest I should tell +anyone of my errand. However, I threw all fears to the winds, ate +a hearty supper, drove to Paddington, and started off, having +obeyed to the letter the injunction as to holding my tongue. + +"At Reading I had to change not only my carriage but my station. +However, I was in time for the last train to Eyford, and I +reached the little dim-lit station after eleven o'clock. I was the +only passenger who got out there, and there was no one upon the +platform save a single sleepy porter with a lantern. As I passed +out through the wicket gate, however, I found my acquaintance of +the morning waiting in the shadow upon the other side. Without a +word he grasped my arm and hurried me into a carriage, the door +of which was standing open. He drew up the windows on either +side, tapped on the wood-work, and away we went as fast as the +horse could go." + +"One horse?" interjected Holmes. + +"Yes, only one." + +"Did you observe the colour?" + +"Yes, I saw it by the side-lights when I was stepping into the +carriage. It was a chestnut." + +"Tired-looking or fresh?" + +"Oh, fresh and glossy." + +"Thank you. I am sorry to have interrupted you. Pray continue +your most interesting statement." + +"Away we went then, and we drove for at least an hour. Colonel +Lysander Stark had said that it was only seven miles, but I +should think, from the rate that we seemed to go, and from the +time that we took, that it must have been nearer twelve. He sat +at my side in silence all the time, and I was aware, more than +once when I glanced in his direction, that he was looking at me +with great intensity. The country roads seem to be not very good +in that part of the world, for we lurched and jolted terribly. I +tried to look out of the windows to see something of where we +were, but they were made of frosted glass, and I could make out +nothing save the occasional bright blur of a passing light. Now +and then I hazarded some remark to break the monotony of the +journey, but the colonel answered only in monosyllables, and the +conversation soon flagged. At last, however, the bumping of the +road was exchanged for the crisp smoothness of a gravel-drive, +and the carriage came to a stand. Colonel Lysander Stark sprang +out, and, as I followed after him, pulled me swiftly into a porch +which gaped in front of us. We stepped, as it were, right out of +the carriage and into the hall, so that I failed to catch the +most fleeting glance of the front of the house. The instant that +I had crossed the threshold the door slammed heavily behind us, +and I heard faintly the rattle of the wheels as the carriage +drove away. + +"It was pitch dark inside the house, and the colonel fumbled +about looking for matches and muttering under his breath. +Suddenly a door opened at the other end of the passage, and a +long, golden bar of light shot out in our direction. It grew +broader, and a woman appeared with a lamp in her hand, which she +held above her head, pushing her face forward and peering at us. +I could see that she was pretty, and from the gloss with which +the light shone upon her dark dress I knew that it was a rich +material. She spoke a few words in a foreign tongue in a tone as +though asking a question, and when my companion answered in a +gruff monosyllable she gave such a start that the lamp nearly +fell from her hand. Colonel Stark went up to her, whispered +something in her ear, and then, pushing her back into the room +from whence she had come, he walked towards me again with the +lamp in his hand. + +"'Perhaps you will have the kindness to wait in this room for a +few minutes,' said he, throwing open another door. It was a +quiet, little, plainly furnished room, with a round table in the +centre, on which several German books were scattered. Colonel +Stark laid down the lamp on the top of a harmonium beside the +door. 'I shall not keep you waiting an instant,' said he, and +vanished into the darkness. + +"I glanced at the books upon the table, and in spite of my +ignorance of German I could see that two of them were treatises +on science, the others being volumes of poetry. Then I walked +across to the window, hoping that I might catch some glimpse of +the country-side, but an oak shutter, heavily barred, was folded +across it. It was a wonderfully silent house. There was an old +clock ticking loudly somewhere in the passage, but otherwise +everything was deadly still. A vague feeling of uneasiness began +to steal over me. Who were these German people, and what were +they doing living in this strange, out-of-the-way place? And +where was the place? I was ten miles or so from Eyford, that was +all I knew, but whether north, south, east, or west I had no +idea. For that matter, Reading, and possibly other large towns, +were within that radius, so the place might not be so secluded, +after all. Yet it was quite certain, from the absolute stillness, +that we were in the country. I paced up and down the room, +humming a tune under my breath to keep up my spirits and feeling +that I was thoroughly earning my fifty-guinea fee. + +"Suddenly, without any preliminary sound in the midst of the +utter stillness, the door of my room swung slowly open. The woman +was standing in the aperture, the darkness of the hall behind +her, the yellow light from my lamp beating upon her eager and +beautiful face. I could see at a glance that she was sick with +fear, and the sight sent a chill to my own heart. She held up one +shaking finger to warn me to be silent, and she shot a few +whispered words of broken English at me, her eyes glancing back, +like those of a frightened horse, into the gloom behind her. + +"'I would go,' said she, trying hard, as it seemed to me, to +speak calmly; 'I would go. I should not stay here. There is no +good for you to do.' + +"'But, madam,' said I, 'I have not yet done what I came for. I +cannot possibly leave until I have seen the machine.' + +"'It is not worth your while to wait,' she went on. 'You can pass +through the door; no one hinders.' And then, seeing that I smiled +and shook my head, she suddenly threw aside her constraint and +made a step forward, with her hands wrung together. 'For the love +of Heaven!' she whispered, 'get away from here before it is too +late!' + +"But I am somewhat headstrong by nature, and the more ready to +engage in an affair when there is some obstacle in the way. I +thought of my fifty-guinea fee, of my wearisome journey, and of +the unpleasant night which seemed to be before me. Was it all to +go for nothing? Why should I slink away without having carried +out my commission, and without the payment which was my due? This +woman might, for all I knew, be a monomaniac. With a stout +bearing, therefore, though her manner had shaken me more than I +cared to confess, I still shook my head and declared my intention +of remaining where I was. She was about to renew her entreaties +when a door slammed overhead, and the sound of several footsteps +was heard upon the stairs. She listened for an instant, threw up +her hands with a despairing gesture, and vanished as suddenly and +as noiselessly as she had come. + +"The newcomers were Colonel Lysander Stark and a short thick man +with a chinchilla beard growing out of the creases of his double +chin, who was introduced to me as Mr. Ferguson. + +"'This is my secretary and manager,' said the colonel. 'By the +way, I was under the impression that I left this door shut just +now. I fear that you have felt the draught.' + +"'On the contrary,' said I, 'I opened the door myself because I +felt the room to be a little close.' + +"He shot one of his suspicious looks at me. 'Perhaps we had +better proceed to business, then,' said he. 'Mr. Ferguson and I +will take you up to see the machine.' + +"'I had better put my hat on, I suppose.' + +"'Oh, no, it is in the house.' + +"'What, you dig fuller's-earth in the house?' + +"'No, no. This is only where we compress it. But never mind that. +All we wish you to do is to examine the machine and to let us +know what is wrong with it.' + +"We went upstairs together, the colonel first with the lamp, the +fat manager and I behind him. It was a labyrinth of an old house, +with corridors, passages, narrow winding staircases, and little +low doors, the thresholds of which were hollowed out by the +generations who had crossed them. There were no carpets and no +signs of any furniture above the ground floor, while the plaster +was peeling off the walls, and the damp was breaking through in +green, unhealthy blotches. I tried to put on as unconcerned an +air as possible, but I had not forgotten the warnings of the +lady, even though I disregarded them, and I kept a keen eye upon +my two companions. Ferguson appeared to be a morose and silent +man, but I could see from the little that he said that he was at +least a fellow-countryman. + +"Colonel Lysander Stark stopped at last before a low door, which +he unlocked. Within was a small, square room, in which the three +of us could hardly get at one time. Ferguson remained outside, +and the colonel ushered me in. + +"'We are now,' said he, 'actually within the hydraulic press, and +it would be a particularly unpleasant thing for us if anyone were +to turn it on. The ceiling of this small chamber is really the +end of the descending piston, and it comes down with the force of +many tons upon this metal floor. There are small lateral columns +of water outside which receive the force, and which transmit and +multiply it in the manner which is familiar to you. The machine +goes readily enough, but there is some stiffness in the working +of it, and it has lost a little of its force. Perhaps you will +have the goodness to look it over and to show us how we can set +it right.' + +"I took the lamp from him, and I examined the machine very +thoroughly. It was indeed a gigantic one, and capable of +exercising enormous pressure. When I passed outside, however, and +pressed down the levers which controlled it, I knew at once by +the whishing sound that there was a slight leakage, which allowed +a regurgitation of water through one of the side cylinders. An +examination showed that one of the india-rubber bands which was +round the head of a driving-rod had shrunk so as not quite to +fill the socket along which it worked. This was clearly the cause +of the loss of power, and I pointed it out to my companions, who +followed my remarks very carefully and asked several practical +questions as to how they should proceed to set it right. When I +had made it clear to them, I returned to the main chamber of the +machine and took a good look at it to satisfy my own curiosity. +It was obvious at a glance that the story of the fuller's-earth +was the merest fabrication, for it would be absurd to suppose +that so powerful an engine could be designed for so inadequate a +purpose. The walls were of wood, but the floor consisted of a +large iron trough, and when I came to examine it I could see a +crust of metallic deposit all over it. I had stooped and was +scraping at this to see exactly what it was when I heard a +muttered exclamation in German and saw the cadaverous face of the +colonel looking down at me. + +"'What are you doing there?' he asked. + +"I felt angry at having been tricked by so elaborate a story as +that which he had told me. 'I was admiring your fuller's-earth,' +said I; 'I think that I should be better able to advise you as to +your machine if I knew what the exact purpose was for which it +was used.' + +"The instant that I uttered the words I regretted the rashness of +my speech. His face set hard, and a baleful light sprang up in +his grey eyes. + +"'Very well,' said he, 'you shall know all about the machine.' He +took a step backward, slammed the little door, and turned the key +in the lock. I rushed towards it and pulled at the handle, but it +was quite secure, and did not give in the least to my kicks and +shoves. 'Hullo!' I yelled. 'Hullo! Colonel! Let me out!' + +"And then suddenly in the silence I heard a sound which sent my +heart into my mouth. It was the clank of the levers and the swish +of the leaking cylinder. He had set the engine at work. The lamp +still stood upon the floor where I had placed it when examining +the trough. By its light I saw that the black ceiling was coming +down upon me, slowly, jerkily, but, as none knew better than +myself, with a force which must within a minute grind me to a +shapeless pulp. I threw myself, screaming, against the door, and +dragged with my nails at the lock. I implored the colonel to let +me out, but the remorseless clanking of the levers drowned my +cries. The ceiling was only a foot or two above my head, and with +my hand upraised I could feel its hard, rough surface. Then it +flashed through my mind that the pain of my death would depend +very much upon the position in which I met it. If I lay on my +face the weight would come upon my spine, and I shuddered to +think of that dreadful snap. Easier the other way, perhaps; and +yet, had I the nerve to lie and look up at that deadly black +shadow wavering down upon me? Already I was unable to stand +erect, when my eye caught something which brought a gush of hope +back to my heart. + +"I have said that though the floor and ceiling were of iron, the +walls were of wood. As I gave a last hurried glance around, I saw +a thin line of yellow light between two of the boards, which +broadened and broadened as a small panel was pushed backward. For +an instant I could hardly believe that here was indeed a door +which led away from death. The next instant I threw myself +through, and lay half-fainting upon the other side. The panel had +closed again behind me, but the crash of the lamp, and a few +moments afterwards the clang of the two slabs of metal, told me +how narrow had been my escape. + +"I was recalled to myself by a frantic plucking at my wrist, and +I found myself lying upon the stone floor of a narrow corridor, +while a woman bent over me and tugged at me with her left hand, +while she held a candle in her right. It was the same good friend +whose warning I had so foolishly rejected. + +"'Come! come!' she cried breathlessly. 'They will be here in a +moment. They will see that you are not there. Oh, do not waste +the so-precious time, but come!' + +"This time, at least, I did not scorn her advice. I staggered to +my feet and ran with her along the corridor and down a winding +stair. The latter led to another broad passage, and just as we +reached it we heard the sound of running feet and the shouting of +two voices, one answering the other from the floor on which we +were and from the one beneath. My guide stopped and looked about +her like one who is at her wit's end. Then she threw open a door +which led into a bedroom, through the window of which the moon +was shining brightly. + +"'It is your only chance,' said she. 'It is high, but it may be +that you can jump it.' + +"As she spoke a light sprang into view at the further end of the +passage, and I saw the lean figure of Colonel Lysander Stark +rushing forward with a lantern in one hand and a weapon like a +butcher's cleaver in the other. I rushed across the bedroom, +flung open the window, and looked out. How quiet and sweet and +wholesome the garden looked in the moonlight, and it could not be +more than thirty feet down. I clambered out upon the sill, but I +hesitated to jump until I should have heard what passed between +my saviour and the ruffian who pursued me. If she were ill-used, +then at any risks I was determined to go back to her assistance. +The thought had hardly flashed through my mind before he was at +the door, pushing his way past her; but she threw her arms round +him and tried to hold him back. + +"'Fritz! Fritz!' she cried in English, 'remember your promise +after the last time. You said it should not be again. He will be +silent! Oh, he will be silent!' + +"'You are mad, Elise!' he shouted, struggling to break away from +her. 'You will be the ruin of us. He has seen too much. Let me +pass, I say!' He dashed her to one side, and, rushing to the +window, cut at me with his heavy weapon. I had let myself go, and +was hanging by the hands to the sill, when his blow fell. I was +conscious of a dull pain, my grip loosened, and I fell into the +garden below. + +"I was shaken but not hurt by the fall; so I picked myself up and +rushed off among the bushes as hard as I could run, for I +understood that I was far from being out of danger yet. Suddenly, +however, as I ran, a deadly dizziness and sickness came over me. +I glanced down at my hand, which was throbbing painfully, and +then, for the first time, saw that my thumb had been cut off and +that the blood was pouring from my wound. I endeavoured to tie my +handkerchief round it, but there came a sudden buzzing in my +ears, and next moment I fell in a dead faint among the +rose-bushes. + +"How long I remained unconscious I cannot tell. It must have been +a very long time, for the moon had sunk, and a bright morning was +breaking when I came to myself. My clothes were all sodden with +dew, and my coat-sleeve was drenched with blood from my wounded +thumb. The smarting of it recalled in an instant all the +particulars of my night's adventure, and I sprang to my feet with +the feeling that I might hardly yet be safe from my pursuers. But +to my astonishment, when I came to look round me, neither house +nor garden were to be seen. I had been lying in an angle of the +hedge close by the highroad, and just a little lower down was a +long building, which proved, upon my approaching it, to be the +very station at which I had arrived upon the previous night. Were +it not for the ugly wound upon my hand, all that had passed +during those dreadful hours might have been an evil dream. + +"Half dazed, I went into the station and asked about the morning +train. There would be one to Reading in less than an hour. The +same porter was on duty, I found, as had been there when I +arrived. I inquired of him whether he had ever heard of Colonel +Lysander Stark. The name was strange to him. Had he observed a +carriage the night before waiting for me? No, he had not. Was +there a police-station anywhere near? There was one about three +miles off. + +"It was too far for me to go, weak and ill as I was. I determined +to wait until I got back to town before telling my story to the +police. It was a little past six when I arrived, so I went first +to have my wound dressed, and then the doctor was kind enough to +bring me along here. I put the case into your hands and shall do +exactly what you advise." + +We both sat in silence for some little time after listening to +this extraordinary narrative. Then Sherlock Holmes pulled down +from the shelf one of the ponderous commonplace books in which he +placed his cuttings. + +"Here is an advertisement which will interest you," said he. "It +appeared in all the papers about a year ago. Listen to this: +'Lost, on the 9th inst., Mr. Jeremiah Hayling, aged +twenty-six, a hydraulic engineer. Left his lodgings at ten +o'clock at night, and has not been heard of since. Was +dressed in,' etc., etc. Ha! That represents the last time that +the colonel needed to have his machine overhauled, I fancy." + +"Good heavens!" cried my patient. "Then that explains what the +girl said." + +"Undoubtedly. It is quite clear that the colonel was a cool and +desperate man, who was absolutely determined that nothing should +stand in the way of his little game, like those out-and-out +pirates who will leave no survivor from a captured ship. Well, +every moment now is precious, so if you feel equal to it we shall +go down to Scotland Yard at once as a preliminary to starting for +Eyford." + +Some three hours or so afterwards we were all in the train +together, bound from Reading to the little Berkshire village. +There were Sherlock Holmes, the hydraulic engineer, Inspector +Bradstreet, of Scotland Yard, a plain-clothes man, and myself. +Bradstreet had spread an ordnance map of the county out upon the +seat and was busy with his compasses drawing a circle with Eyford +for its centre. + +"There you are," said he. "That circle is drawn at a radius of +ten miles from the village. The place we want must be somewhere +near that line. You said ten miles, I think, sir." + +"It was an hour's good drive." + +"And you think that they brought you back all that way when you +were unconscious?" + +"They must have done so. I have a confused memory, too, of having +been lifted and conveyed somewhere." + +"What I cannot understand," said I, "is why they should have +spared you when they found you lying fainting in the garden. +Perhaps the villain was softened by the woman's entreaties." + +"I hardly think that likely. I never saw a more inexorable face +in my life." + +"Oh, we shall soon clear up all that," said Bradstreet. "Well, I +have drawn my circle, and I only wish I knew at what point upon +it the folk that we are in search of are to be found." + +"I think I could lay my finger on it," said Holmes quietly. + +"Really, now!" cried the inspector, "you have formed your +opinion! Come, now, we shall see who agrees with you. I say it is +south, for the country is more deserted there." + +"And I say east," said my patient. + +"I am for west," remarked the plain-clothes man. "There are +several quiet little villages up there." + +"And I am for north," said I, "because there are no hills there, +and our friend says that he did not notice the carriage go up +any." + +"Come," cried the inspector, laughing; "it's a very pretty +diversity of opinion. We have boxed the compass among us. Who do +you give your casting vote to?" + +"You are all wrong." + +"But we can't all be." + +"Oh, yes, you can. This is my point." He placed his finger in the +centre of the circle. "This is where we shall find them." + +"But the twelve-mile drive?" gasped Hatherley. + +"Six out and six back. Nothing simpler. You say yourself that the +horse was fresh and glossy when you got in. How could it be that +if it had gone twelve miles over heavy roads?" + +"Indeed, it is a likely ruse enough," observed Bradstreet +thoughtfully. "Of course there can be no doubt as to the nature +of this gang." + +"None at all," said Holmes. "They are coiners on a large scale, +and have used the machine to form the amalgam which has taken the +place of silver." + +"We have known for some time that a clever gang was at work," +said the inspector. "They have been turning out half-crowns by +the thousand. We even traced them as far as Reading, but could +get no farther, for they had covered their traces in a way that +showed that they were very old hands. But now, thanks to this +lucky chance, I think that we have got them right enough." + +But the inspector was mistaken, for those criminals were not +destined to fall into the hands of justice. As we rolled into +Eyford Station we saw a gigantic column of smoke which streamed +up from behind a small clump of trees in the neighbourhood and +hung like an immense ostrich feather over the landscape. + +"A house on fire?" asked Bradstreet as the train steamed off +again on its way. + +"Yes, sir!" said the station-master. + +"When did it break out?" + +"I hear that it was during the night, sir, but it has got worse, +and the whole place is in a blaze." + +"Whose house is it?" + +"Dr. Becher's." + +"Tell me," broke in the engineer, "is Dr. Becher a German, very +thin, with a long, sharp nose?" + +The station-master laughed heartily. "No, sir, Dr. Becher is an +Englishman, and there isn't a man in the parish who has a +better-lined waistcoat. But he has a gentleman staying with him, +a patient, as I understand, who is a foreigner, and he looks as +if a little good Berkshire beef would do him no harm." + +The station-master had not finished his speech before we were all +hastening in the direction of the fire. The road topped a low +hill, and there was a great widespread whitewashed building in +front of us, spouting fire at every chink and window, while in +the garden in front three fire-engines were vainly striving to +keep the flames under. + +"That's it!" cried Hatherley, in intense excitement. "There is +the gravel-drive, and there are the rose-bushes where I lay. That +second window is the one that I jumped from." + +"Well, at least," said Holmes, "you have had your revenge upon +them. There can be no question that it was your oil-lamp which, +when it was crushed in the press, set fire to the wooden walls, +though no doubt they were too excited in the chase after you to +observe it at the time. Now keep your eyes open in this crowd for +your friends of last night, though I very much fear that they are +a good hundred miles off by now." + +And Holmes' fears came to be realised, for from that day to this +no word has ever been heard either of the beautiful woman, the +sinister German, or the morose Englishman. Early that morning a +peasant had met a cart containing several people and some very +bulky boxes driving rapidly in the direction of Reading, but +there all traces of the fugitives disappeared, and even Holmes' +ingenuity failed ever to discover the least clue as to their +whereabouts. + +The firemen had been much perturbed at the strange arrangements +which they had found within, and still more so by discovering a +newly severed human thumb upon a window-sill of the second floor. +About sunset, however, their efforts were at last successful, and +they subdued the flames, but not before the roof had fallen in, +and the whole place been reduced to such absolute ruin that, save +some twisted cylinders and iron piping, not a trace remained of +the machinery which had cost our unfortunate acquaintance so +dearly. Large masses of nickel and of tin were discovered stored +in an out-house, but no coins were to be found, which may have +explained the presence of those bulky boxes which have been +already referred to. + +How our hydraulic engineer had been conveyed from the garden to +the spot where he recovered his senses might have remained +forever a mystery were it not for the soft mould, which told us a +very plain tale. He had evidently been carried down by two +persons, one of whom had remarkably small feet and the other +unusually large ones. On the whole, it was most probable that the +silent Englishman, being less bold or less murderous than his +companion, had assisted the woman to bear the unconscious man out +of the way of danger. + +"Well," said our engineer ruefully as we took our seats to return +once more to London, "it has been a pretty business for me! I +have lost my thumb and I have lost a fifty-guinea fee, and what +have I gained?" + +"Experience," said Holmes, laughing. "Indirectly it may be of +value, you know; you have only to put it into words to gain the +reputation of being excellent company for the remainder of your +existence." + + + +X. THE ADVENTURE OF THE NOBLE BACHELOR + +The Lord St. Simon marriage, and its curious termination, have +long ceased to be a subject of interest in those exalted circles +in which the unfortunate bridegroom moves. Fresh scandals have +eclipsed it, and their more piquant details have drawn the +gossips away from this four-year-old drama. As I have reason to +believe, however, that the full facts have never been revealed to +the general public, and as my friend Sherlock Holmes had a +considerable share in clearing the matter up, I feel that no +memoir of him would be complete without some little sketch of +this remarkable episode. + +It was a few weeks before my own marriage, during the days when I +was still sharing rooms with Holmes in Baker Street, that he came +home from an afternoon stroll to find a letter on the table +waiting for him. I had remained indoors all day, for the weather +had taken a sudden turn to rain, with high autumnal winds, and +the Jezail bullet which I had brought back in one of my limbs as +a relic of my Afghan campaign throbbed with dull persistence. +With my body in one easy-chair and my legs upon another, I had +surrounded myself with a cloud of newspapers until at last, +saturated with the news of the day, I tossed them all aside and +lay listless, watching the huge crest and monogram upon the +envelope upon the table and wondering lazily who my friend's +noble correspondent could be. + +"Here is a very fashionable epistle," I remarked as he entered. +"Your morning letters, if I remember right, were from a +fish-monger and a tide-waiter." + +"Yes, my correspondence has certainly the charm of variety," he +answered, smiling, "and the humbler are usually the more +interesting. This looks like one of those unwelcome social +summonses which call upon a man either to be bored or to lie." + +He broke the seal and glanced over the contents. + +"Oh, come, it may prove to be something of interest, after all." + +"Not social, then?" + +"No, distinctly professional." + +"And from a noble client?" + +"One of the highest in England." + +"My dear fellow, I congratulate you." + +"I assure you, Watson, without affectation, that the status of my +client is a matter of less moment to me than the interest of his +case. It is just possible, however, that that also may not be +wanting in this new investigation. You have been reading the +papers diligently of late, have you not?" + +"It looks like it," said I ruefully, pointing to a huge bundle in +the corner. "I have had nothing else to do." + +"It is fortunate, for you will perhaps be able to post me up. I +read nothing except the criminal news and the agony column. The +latter is always instructive. But if you have followed recent +events so closely you must have read about Lord St. Simon and his +wedding?" + +"Oh, yes, with the deepest interest." + +"That is well. The letter which I hold in my hand is from Lord +St. Simon. I will read it to you, and in return you must turn +over these papers and let me have whatever bears upon the matter. +This is what he says: + +"'MY DEAR MR. SHERLOCK HOLMES:--Lord Backwater tells me that I +may place implicit reliance upon your judgment and discretion. I +have determined, therefore, to call upon you and to consult you +in reference to the very painful event which has occurred in +connection with my wedding. Mr. Lestrade, of Scotland Yard, is +acting already in the matter, but he assures me that he sees no +objection to your co-operation, and that he even thinks that +it might be of some assistance. I will call at four o'clock in +the afternoon, and, should you have any other engagement at that +time, I hope that you will postpone it, as this matter is of +paramount importance. Yours faithfully, ST. SIMON.' + +"It is dated from Grosvenor Mansions, written with a quill pen, +and the noble lord has had the misfortune to get a smear of ink +upon the outer side of his right little finger," remarked Holmes +as he folded up the epistle. + +"He says four o'clock. It is three now. He will be here in an +hour." + +"Then I have just time, with your assistance, to get clear upon +the subject. Turn over those papers and arrange the extracts in +their order of time, while I take a glance as to who our client +is." He picked a red-covered volume from a line of books of +reference beside the mantelpiece. "Here he is," said he, sitting +down and flattening it out upon his knee. "'Lord Robert Walsingham +de Vere St. Simon, second son of the Duke of Balmoral.' Hum! 'Arms: +Azure, three caltrops in chief over a fess sable. Born in 1846.' +He's forty-one years of age, which is mature for marriage. Was +Under-Secretary for the colonies in a late administration. The +Duke, his father, was at one time Secretary for Foreign Affairs. +They inherit Plantagenet blood by direct descent, and Tudor on +the distaff side. Ha! Well, there is nothing very instructive in +all this. I think that I must turn to you Watson, for something +more solid." + +"I have very little difficulty in finding what I want," said I, +"for the facts are quite recent, and the matter struck me as +remarkable. I feared to refer them to you, however, as I knew +that you had an inquiry on hand and that you disliked the +intrusion of other matters." + +"Oh, you mean the little problem of the Grosvenor Square +furniture van. That is quite cleared up now--though, indeed, it +was obvious from the first. Pray give me the results of your +newspaper selections." + +"Here is the first notice which I can find. It is in the personal +column of the Morning Post, and dates, as you see, some weeks +back: 'A marriage has been arranged,' it says, 'and will, if +rumour is correct, very shortly take place, between Lord Robert +St. Simon, second son of the Duke of Balmoral, and Miss Hatty +Doran, the only daughter of Aloysius Doran. Esq., of San +Francisco, Cal., U.S.A.' That is all." + +"Terse and to the point," remarked Holmes, stretching his long, +thin legs towards the fire. + +"There was a paragraph amplifying this in one of the society +papers of the same week. Ah, here it is: 'There will soon be a +call for protection in the marriage market, for the present +free-trade principle appears to tell heavily against our home +product. One by one the management of the noble houses of Great +Britain is passing into the hands of our fair cousins from across +the Atlantic. An important addition has been made during the last +week to the list of the prizes which have been borne away by +these charming invaders. Lord St. Simon, who has shown himself +for over twenty years proof against the little god's arrows, has +now definitely announced his approaching marriage with Miss Hatty +Doran, the fascinating daughter of a California millionaire. Miss +Doran, whose graceful figure and striking face attracted much +attention at the Westbury House festivities, is an only child, +and it is currently reported that her dowry will run to +considerably over the six figures, with expectancies for the +future. As it is an open secret that the Duke of Balmoral has +been compelled to sell his pictures within the last few years, +and as Lord St. Simon has no property of his own save the small +estate of Birchmoor, it is obvious that the Californian heiress +is not the only gainer by an alliance which will enable her to +make the easy and common transition from a Republican lady to a +British peeress.'" + +"Anything else?" asked Holmes, yawning. + +"Oh, yes; plenty. Then there is another note in the Morning Post +to say that the marriage would be an absolutely quiet one, that it +would be at St. George's, Hanover Square, that only half a dozen +intimate friends would be invited, and that the party would +return to the furnished house at Lancaster Gate which has been +taken by Mr. Aloysius Doran. Two days later--that is, on +Wednesday last--there is a curt announcement that the wedding had +taken place, and that the honeymoon would be passed at Lord +Backwater's place, near Petersfield. Those are all the notices +which appeared before the disappearance of the bride." + +"Before the what?" asked Holmes with a start. + +"The vanishing of the lady." + +"When did she vanish, then?" + +"At the wedding breakfast." + +"Indeed. This is more interesting than it promised to be; quite +dramatic, in fact." + +"Yes; it struck me as being a little out of the common." + +"They often vanish before the ceremony, and occasionally during +the honeymoon; but I cannot call to mind anything quite so prompt +as this. Pray let me have the details." + +"I warn you that they are very incomplete." + +"Perhaps we may make them less so." + +"Such as they are, they are set forth in a single article of a +morning paper of yesterday, which I will read to you. It is +headed, 'Singular Occurrence at a Fashionable Wedding': + +"'The family of Lord Robert St. Simon has been thrown into the +greatest consternation by the strange and painful episodes which +have taken place in connection with his wedding. The ceremony, as +shortly announced in the papers of yesterday, occurred on the +previous morning; but it is only now that it has been possible to +confirm the strange rumours which have been so persistently +floating about. In spite of the attempts of the friends to hush +the matter up, so much public attention has now been drawn to it +that no good purpose can be served by affecting to disregard what +is a common subject for conversation. + +"'The ceremony, which was performed at St. George's, Hanover +Square, was a very quiet one, no one being present save the +father of the bride, Mr. Aloysius Doran, the Duchess of Balmoral, +Lord Backwater, Lord Eustace and Lady Clara St. Simon (the +younger brother and sister of the bridegroom), and Lady Alicia +Whittington. The whole party proceeded afterwards to the house of +Mr. Aloysius Doran, at Lancaster Gate, where breakfast had been +prepared. It appears that some little trouble was caused by a +woman, whose name has not been ascertained, who endeavoured to +force her way into the house after the bridal party, alleging +that she had some claim upon Lord St. Simon. It was only after a +painful and prolonged scene that she was ejected by the butler +and the footman. The bride, who had fortunately entered the house +before this unpleasant interruption, had sat down to breakfast +with the rest, when she complained of a sudden indisposition and +retired to her room. Her prolonged absence having caused some +comment, her father followed her, but learned from her maid that +she had only come up to her chamber for an instant, caught up an +ulster and bonnet, and hurried down to the passage. One of the +footmen declared that he had seen a lady leave the house thus +apparelled, but had refused to credit that it was his mistress, +believing her to be with the company. On ascertaining that his +daughter had disappeared, Mr. Aloysius Doran, in conjunction with +the bridegroom, instantly put themselves in communication with +the police, and very energetic inquiries are being made, which +will probably result in a speedy clearing up of this very +singular business. Up to a late hour last night, however, nothing +had transpired as to the whereabouts of the missing lady. There +are rumours of foul play in the matter, and it is said that the +police have caused the arrest of the woman who had caused the +original disturbance, in the belief that, from jealousy or some +other motive, she may have been concerned in the strange +disappearance of the bride.'" + +"And is that all?" + +"Only one little item in another of the morning papers, but it is +a suggestive one." + +"And it is--" + +"That Miss Flora Millar, the lady who had caused the disturbance, +has actually been arrested. It appears that she was formerly a +danseuse at the Allegro, and that she has known the bridegroom +for some years. There are no further particulars, and the whole +case is in your hands now--so far as it has been set forth in the +public press." + +"And an exceedingly interesting case it appears to be. I would +not have missed it for worlds. But there is a ring at the bell, +Watson, and as the clock makes it a few minutes after four, I +have no doubt that this will prove to be our noble client. Do not +dream of going, Watson, for I very much prefer having a witness, +if only as a check to my own memory." + +"Lord Robert St. Simon," announced our page-boy, throwing open +the door. A gentleman entered, with a pleasant, cultured face, +high-nosed and pale, with something perhaps of petulance about +the mouth, and with the steady, well-opened eye of a man whose +pleasant lot it had ever been to command and to be obeyed. His +manner was brisk, and yet his general appearance gave an undue +impression of age, for he had a slight forward stoop and a little +bend of the knees as he walked. His hair, too, as he swept off +his very curly-brimmed hat, was grizzled round the edges and thin +upon the top. As to his dress, it was careful to the verge of +foppishness, with high collar, black frock-coat, white waistcoat, +yellow gloves, patent-leather shoes, and light-coloured gaiters. +He advanced slowly into the room, turning his head from left to +right, and swinging in his right hand the cord which held his +golden eyeglasses. + +"Good-day, Lord St. Simon," said Holmes, rising and bowing. "Pray +take the basket-chair. This is my friend and colleague, Dr. +Watson. Draw up a little to the fire, and we will talk this +matter over." + +"A most painful matter to me, as you can most readily imagine, +Mr. Holmes. I have been cut to the quick. I understand that you +have already managed several delicate cases of this sort, sir, +though I presume that they were hardly from the same class of +society." + +"No, I am descending." + +"I beg pardon." + +"My last client of the sort was a king." + +"Oh, really! I had no idea. And which king?" + +"The King of Scandinavia." + +"What! Had he lost his wife?" + +"You can understand," said Holmes suavely, "that I extend to the +affairs of my other clients the same secrecy which I promise to +you in yours." + +"Of course! Very right! very right! I'm sure I beg pardon. As to +my own case, I am ready to give you any information which may +assist you in forming an opinion." + +"Thank you. I have already learned all that is in the public +prints, nothing more. I presume that I may take it as correct--this +article, for example, as to the disappearance of the bride." + +Lord St. Simon glanced over it. "Yes, it is correct, as far as it +goes." + +"But it needs a great deal of supplementing before anyone could +offer an opinion. I think that I may arrive at my facts most +directly by questioning you." + +"Pray do so." + +"When did you first meet Miss Hatty Doran?" + +"In San Francisco, a year ago." + +"You were travelling in the States?" + +"Yes." + +"Did you become engaged then?" + +"No." + +"But you were on a friendly footing?" + +"I was amused by her society, and she could see that I was +amused." + +"Her father is very rich?" + +"He is said to be the richest man on the Pacific slope." + +"And how did he make his money?" + +"In mining. He had nothing a few years ago. Then he struck gold, +invested it, and came up by leaps and bounds." + +"Now, what is your own impression as to the young lady's--your +wife's character?" + +The nobleman swung his glasses a little faster and stared down +into the fire. "You see, Mr. Holmes," said he, "my wife was +twenty before her father became a rich man. During that time she +ran free in a mining camp and wandered through woods or +mountains, so that her education has come from Nature rather than +from the schoolmaster. She is what we call in England a tomboy, +with a strong nature, wild and free, unfettered by any sort of +traditions. She is impetuous--volcanic, I was about to say. She +is swift in making up her mind and fearless in carrying out her +resolutions. On the other hand, I would not have given her the +name which I have the honour to bear"--he gave a little stately +cough--"had not I thought her to be at bottom a noble woman. I +believe that she is capable of heroic self-sacrifice and that +anything dishonourable would be repugnant to her." + +"Have you her photograph?" + +"I brought this with me." He opened a locket and showed us the +full face of a very lovely woman. It was not a photograph but an +ivory miniature, and the artist had brought out the full effect +of the lustrous black hair, the large dark eyes, and the +exquisite mouth. Holmes gazed long and earnestly at it. Then he +closed the locket and handed it back to Lord St. Simon. + +"The young lady came to London, then, and you renewed your +acquaintance?" + +"Yes, her father brought her over for this last London season. I +met her several times, became engaged to her, and have now +married her." + +"She brought, I understand, a considerable dowry?" + +"A fair dowry. Not more than is usual in my family." + +"And this, of course, remains to you, since the marriage is a +fait accompli?" + +"I really have made no inquiries on the subject." + +"Very naturally not. Did you see Miss Doran on the day before the +wedding?" + +"Yes." + +"Was she in good spirits?" + +"Never better. She kept talking of what we should do in our +future lives." + +"Indeed! That is very interesting. And on the morning of the +wedding?" + +"She was as bright as possible--at least until after the +ceremony." + +"And did you observe any change in her then?" + +"Well, to tell the truth, I saw then the first signs that I had +ever seen that her temper was just a little sharp. The incident +however, was too trivial to relate and can have no possible +bearing upon the case." + +"Pray let us have it, for all that." + +"Oh, it is childish. She dropped her bouquet as we went towards +the vestry. She was passing the front pew at the time, and it +fell over into the pew. There was a moment's delay, but the +gentleman in the pew handed it up to her again, and it did not +appear to be the worse for the fall. Yet when I spoke to her of +the matter, she answered me abruptly; and in the carriage, on our +way home, she seemed absurdly agitated over this trifling cause." + +"Indeed! You say that there was a gentleman in the pew. Some of +the general public were present, then?" + +"Oh, yes. It is impossible to exclude them when the church is +open." + +"This gentleman was not one of your wife's friends?" + +"No, no; I call him a gentleman by courtesy, but he was quite a +common-looking person. I hardly noticed his appearance. But +really I think that we are wandering rather far from the point." + +"Lady St. Simon, then, returned from the wedding in a less +cheerful frame of mind than she had gone to it. What did she do +on re-entering her father's house?" + +"I saw her in conversation with her maid." + +"And who is her maid?" + +"Alice is her name. She is an American and came from California +with her." + +"A confidential servant?" + +"A little too much so. It seemed to me that her mistress allowed +her to take great liberties. Still, of course, in America they +look upon these things in a different way." + +"How long did she speak to this Alice?" + +"Oh, a few minutes. I had something else to think of." + +"You did not overhear what they said?" + +"Lady St. Simon said something about 'jumping a claim.' She was +accustomed to use slang of the kind. I have no idea what she +meant." + +"American slang is very expressive sometimes. And what did your +wife do when she finished speaking to her maid?" + +"She walked into the breakfast-room." + +"On your arm?" + +"No, alone. She was very independent in little matters like that. +Then, after we had sat down for ten minutes or so, she rose +hurriedly, muttered some words of apology, and left the room. She +never came back." + +"But this maid, Alice, as I understand, deposes that she went to +her room, covered her bride's dress with a long ulster, put on a +bonnet, and went out." + +"Quite so. And she was afterwards seen walking into Hyde Park in +company with Flora Millar, a woman who is now in custody, and who +had already made a disturbance at Mr. Doran's house that +morning." + +"Ah, yes. I should like a few particulars as to this young lady, +and your relations to her." + +Lord St. Simon shrugged his shoulders and raised his eyebrows. +"We have been on a friendly footing for some years--I may say on +a very friendly footing. She used to be at the Allegro. I have +not treated her ungenerously, and she had no just cause of +complaint against me, but you know what women are, Mr. Holmes. +Flora was a dear little thing, but exceedingly hot-headed and +devotedly attached to me. She wrote me dreadful letters when she +heard that I was about to be married, and, to tell the truth, the +reason why I had the marriage celebrated so quietly was that I +feared lest there might be a scandal in the church. She came to +Mr. Doran's door just after we returned, and she endeavoured to +push her way in, uttering very abusive expressions towards my +wife, and even threatening her, but I had foreseen the +possibility of something of the sort, and I had two police +fellows there in private clothes, who soon pushed her out again. +She was quiet when she saw that there was no good in making a +row." + +"Did your wife hear all this?" + +"No, thank goodness, she did not." + +"And she was seen walking with this very woman afterwards?" + +"Yes. That is what Mr. Lestrade, of Scotland Yard, looks upon as +so serious. It is thought that Flora decoyed my wife out and laid +some terrible trap for her." + +"Well, it is a possible supposition." + +"You think so, too?" + +"I did not say a probable one. But you do not yourself look upon +this as likely?" + +"I do not think Flora would hurt a fly." + +"Still, jealousy is a strange transformer of characters. Pray +what is your own theory as to what took place?" + +"Well, really, I came to seek a theory, not to propound one. I +have given you all the facts. Since you ask me, however, I may +say that it has occurred to me as possible that the excitement of +this affair, the consciousness that she had made so immense a +social stride, had the effect of causing some little nervous +disturbance in my wife." + +"In short, that she had become suddenly deranged?" + +"Well, really, when I consider that she has turned her back--I +will not say upon me, but upon so much that many have aspired to +without success--I can hardly explain it in any other fashion." + +"Well, certainly that is also a conceivable hypothesis," said +Holmes, smiling. "And now, Lord St. Simon, I think that I have +nearly all my data. May I ask whether you were seated at the +breakfast-table so that you could see out of the window?" + +"We could see the other side of the road and the Park." + +"Quite so. Then I do not think that I need to detain you longer. +I shall communicate with you." + +"Should you be fortunate enough to solve this problem," said our +client, rising. + +"I have solved it." + +"Eh? What was that?" + +"I say that I have solved it." + +"Where, then, is my wife?" + +"That is a detail which I shall speedily supply." + +Lord St. Simon shook his head. "I am afraid that it will take +wiser heads than yours or mine," he remarked, and bowing in a +stately, old-fashioned manner he departed. + +"It is very good of Lord St. Simon to honour my head by putting +it on a level with his own," said Sherlock Holmes, laughing. "I +think that I shall have a whisky and soda and a cigar after all +this cross-questioning. I had formed my conclusions as to the +case before our client came into the room." + +"My dear Holmes!" + +"I have notes of several similar cases, though none, as I +remarked before, which were quite as prompt. My whole examination +served to turn my conjecture into a certainty. Circumstantial +evidence is occasionally very convincing, as when you find a +trout in the milk, to quote Thoreau's example." + +"But I have heard all that you have heard." + +"Without, however, the knowledge of pre-existing cases which +serves me so well. There was a parallel instance in Aberdeen some +years back, and something on very much the same lines at Munich +the year after the Franco-Prussian War. It is one of these +cases--but, hullo, here is Lestrade! Good-afternoon, Lestrade! +You will find an extra tumbler upon the sideboard, and there are +cigars in the box." + +The official detective was attired in a pea-jacket and cravat, +which gave him a decidedly nautical appearance, and he carried a +black canvas bag in his hand. With a short greeting he seated +himself and lit the cigar which had been offered to him. + +"What's up, then?" asked Holmes with a twinkle in his eye. "You +look dissatisfied." + +"And I feel dissatisfied. It is this infernal St. Simon marriage +case. I can make neither head nor tail of the business." + +"Really! You surprise me." + +"Who ever heard of such a mixed affair? Every clue seems to slip +through my fingers. I have been at work upon it all day." + +"And very wet it seems to have made you," said Holmes laying his +hand upon the arm of the pea-jacket. + +"Yes, I have been dragging the Serpentine." + +"In heaven's name, what for?" + +"In search of the body of Lady St. Simon." + +Sherlock Holmes leaned back in his chair and laughed heartily. + +"Have you dragged the basin of Trafalgar Square fountain?" he +asked. + +"Why? What do you mean?" + +"Because you have just as good a chance of finding this lady in +the one as in the other." + +Lestrade shot an angry glance at my companion. "I suppose you +know all about it," he snarled. + +"Well, I have only just heard the facts, but my mind is made up." + +"Oh, indeed! Then you think that the Serpentine plays no part in +the matter?" + +"I think it very unlikely." + +"Then perhaps you will kindly explain how it is that we found +this in it?" He opened his bag as he spoke, and tumbled onto the +floor a wedding-dress of watered silk, a pair of white satin +shoes and a bride's wreath and veil, all discoloured and soaked +in water. "There," said he, putting a new wedding-ring upon the +top of the pile. "There is a little nut for you to crack, Master +Holmes." + +"Oh, indeed!" said my friend, blowing blue rings into the air. +"You dragged them from the Serpentine?" + +"No. They were found floating near the margin by a park-keeper. +They have been identified as her clothes, and it seemed to me +that if the clothes were there the body would not be far off." + +"By the same brilliant reasoning, every man's body is to be found +in the neighbourhood of his wardrobe. And pray what did you hope +to arrive at through this?" + +"At some evidence implicating Flora Millar in the disappearance." + +"I am afraid that you will find it difficult." + +"Are you, indeed, now?" cried Lestrade with some bitterness. "I +am afraid, Holmes, that you are not very practical with your +deductions and your inferences. You have made two blunders in as +many minutes. This dress does implicate Miss Flora Millar." + +"And how?" + +"In the dress is a pocket. In the pocket is a card-case. In the +card-case is a note. And here is the very note." He slapped it +down upon the table in front of him. "Listen to this: 'You will +see me when all is ready. Come at once. F.H.M.' Now my theory all +along has been that Lady St. Simon was decoyed away by Flora +Millar, and that she, with confederates, no doubt, was +responsible for her disappearance. Here, signed with her +initials, is the very note which was no doubt quietly slipped +into her hand at the door and which lured her within their +reach." + +"Very good, Lestrade," said Holmes, laughing. "You really are +very fine indeed. Let me see it." He took up the paper in a +listless way, but his attention instantly became riveted, and he +gave a little cry of satisfaction. "This is indeed important," +said he. + +"Ha! you find it so?" + +"Extremely so. I congratulate you warmly." + +Lestrade rose in his triumph and bent his head to look. "Why," he +shrieked, "you're looking at the wrong side!" + +"On the contrary, this is the right side." + +"The right side? You're mad! Here is the note written in pencil +over here." + +"And over here is what appears to be the fragment of a hotel +bill, which interests me deeply." + +"There's nothing in it. I looked at it before," said Lestrade. +"'Oct. 4th, rooms 8s., breakfast 2s. 6d., cocktail 1s., lunch 2s. +6d., glass sherry, 8d.' I see nothing in that." + +"Very likely not. It is most important, all the same. As to the +note, it is important also, or at least the initials are, so I +congratulate you again." + +"I've wasted time enough," said Lestrade, rising. "I believe in +hard work and not in sitting by the fire spinning fine theories. +Good-day, Mr. Holmes, and we shall see which gets to the bottom +of the matter first." He gathered up the garments, thrust them +into the bag, and made for the door. + +"Just one hint to you, Lestrade," drawled Holmes before his rival +vanished; "I will tell you the true solution of the matter. Lady +St. Simon is a myth. There is not, and there never has been, any +such person." + +Lestrade looked sadly at my companion. Then he turned to me, +tapped his forehead three times, shook his head solemnly, and +hurried away. + +He had hardly shut the door behind him when Holmes rose to put on +his overcoat. "There is something in what the fellow says about +outdoor work," he remarked, "so I think, Watson, that I must +leave you to your papers for a little." + +It was after five o'clock when Sherlock Holmes left me, but I had +no time to be lonely, for within an hour there arrived a +confectioner's man with a very large flat box. This he unpacked +with the help of a youth whom he had brought with him, and +presently, to my very great astonishment, a quite epicurean +little cold supper began to be laid out upon our humble +lodging-house mahogany. There were a couple of brace of cold +woodcock, a pheasant, a pâté de foie gras pie with a group of +ancient and cobwebby bottles. Having laid out all these luxuries, +my two visitors vanished away, like the genii of the Arabian +Nights, with no explanation save that the things had been paid +for and were ordered to this address. + +Just before nine o'clock Sherlock Holmes stepped briskly into the +room. His features were gravely set, but there was a light in his +eye which made me think that he had not been disappointed in his +conclusions. + +"They have laid the supper, then," he said, rubbing his hands. + +"You seem to expect company. They have laid for five." + +"Yes, I fancy we may have some company dropping in," said he. "I +am surprised that Lord St. Simon has not already arrived. Ha! I +fancy that I hear his step now upon the stairs." + +It was indeed our visitor of the afternoon who came bustling in, +dangling his glasses more vigorously than ever, and with a very +perturbed expression upon his aristocratic features. + +"My messenger reached you, then?" asked Holmes. + +"Yes, and I confess that the contents startled me beyond measure. +Have you good authority for what you say?" + +"The best possible." + +Lord St. Simon sank into a chair and passed his hand over his +forehead. + +"What will the Duke say," he murmured, "when he hears that one of +the family has been subjected to such humiliation?" + +"It is the purest accident. I cannot allow that there is any +humiliation." + +"Ah, you look on these things from another standpoint." + +"I fail to see that anyone is to blame. I can hardly see how the +lady could have acted otherwise, though her abrupt method of +doing it was undoubtedly to be regretted. Having no mother, she +had no one to advise her at such a crisis." + +"It was a slight, sir, a public slight," said Lord St. Simon, +tapping his fingers upon the table. + +"You must make allowance for this poor girl, placed in so +unprecedented a position." + +"I will make no allowance. I am very angry indeed, and I have +been shamefully used." + +"I think that I heard a ring," said Holmes. "Yes, there are steps +on the landing. If I cannot persuade you to take a lenient view +of the matter, Lord St. Simon, I have brought an advocate here +who may be more successful." He opened the door and ushered in a +lady and gentleman. "Lord St. Simon," said he "allow me to +introduce you to Mr. and Mrs. Francis Hay Moulton. The lady, I +think, you have already met." + +At the sight of these newcomers our client had sprung from his +seat and stood very erect, with his eyes cast down and his hand +thrust into the breast of his frock-coat, a picture of offended +dignity. The lady had taken a quick step forward and had held out +her hand to him, but he still refused to raise his eyes. It was +as well for his resolution, perhaps, for her pleading face was +one which it was hard to resist. + +"You're angry, Robert," said she. "Well, I guess you have every +cause to be." + +"Pray make no apology to me," said Lord St. Simon bitterly. + +"Oh, yes, I know that I have treated you real bad and that I +should have spoken to you before I went; but I was kind of +rattled, and from the time when I saw Frank here again I just +didn't know what I was doing or saying. I only wonder I didn't +fall down and do a faint right there before the altar." + +"Perhaps, Mrs. Moulton, you would like my friend and me to leave +the room while you explain this matter?" + +"If I may give an opinion," remarked the strange gentleman, +"we've had just a little too much secrecy over this business +already. For my part, I should like all Europe and America to +hear the rights of it." He was a small, wiry, sunburnt man, +clean-shaven, with a sharp face and alert manner. + +"Then I'll tell our story right away," said the lady. "Frank here +and I met in '84, in McQuire's camp, near the Rockies, where pa +was working a claim. We were engaged to each other, Frank and I; +but then one day father struck a rich pocket and made a pile, +while poor Frank here had a claim that petered out and came to +nothing. The richer pa grew the poorer was Frank; so at last pa +wouldn't hear of our engagement lasting any longer, and he took +me away to 'Frisco. Frank wouldn't throw up his hand, though; so +he followed me there, and he saw me without pa knowing anything +about it. It would only have made him mad to know, so we just +fixed it all up for ourselves. Frank said that he would go and +make his pile, too, and never come back to claim me until he had +as much as pa. So then I promised to wait for him to the end of +time and pledged myself not to marry anyone else while he lived. +'Why shouldn't we be married right away, then,' said he, 'and +then I will feel sure of you; and I won't claim to be your +husband until I come back?' Well, we talked it over, and he had +fixed it all up so nicely, with a clergyman all ready in waiting, +that we just did it right there; and then Frank went off to seek +his fortune, and I went back to pa. + +"The next I heard of Frank was that he was in Montana, and then +he went prospecting in Arizona, and then I heard of him from New +Mexico. After that came a long newspaper story about how a +miners' camp had been attacked by Apache Indians, and there was +my Frank's name among the killed. I fainted dead away, and I was +very sick for months after. Pa thought I had a decline and took +me to half the doctors in 'Frisco. Not a word of news came for a +year and more, so that I never doubted that Frank was really +dead. Then Lord St. Simon came to 'Frisco, and we came to London, +and a marriage was arranged, and pa was very pleased, but I felt +all the time that no man on this earth would ever take the place +in my heart that had been given to my poor Frank. + +"Still, if I had married Lord St. Simon, of course I'd have done +my duty by him. We can't command our love, but we can our +actions. I went to the altar with him with the intention to make +him just as good a wife as it was in me to be. But you may +imagine what I felt when, just as I came to the altar rails, I +glanced back and saw Frank standing and looking at me out of the +first pew. I thought it was his ghost at first; but when I looked +again there he was still, with a kind of question in his eyes, as +if to ask me whether I were glad or sorry to see him. I wonder I +didn't drop. I know that everything was turning round, and the +words of the clergyman were just like the buzz of a bee in my +ear. I didn't know what to do. Should I stop the service and make +a scene in the church? I glanced at him again, and he seemed to +know what I was thinking, for he raised his finger to his lips to +tell me to be still. Then I saw him scribble on a piece of paper, +and I knew that he was writing me a note. As I passed his pew on +the way out I dropped my bouquet over to him, and he slipped the +note into my hand when he returned me the flowers. It was only a +line asking me to join him when he made the sign to me to do so. +Of course I never doubted for a moment that my first duty was now +to him, and I determined to do just whatever he might direct. + +"When I got back I told my maid, who had known him in California, +and had always been his friend. I ordered her to say nothing, but +to get a few things packed and my ulster ready. I know I ought to +have spoken to Lord St. Simon, but it was dreadful hard before +his mother and all those great people. I just made up my mind to +run away and explain afterwards. I hadn't been at the table ten +minutes before I saw Frank out of the window at the other side of +the road. He beckoned to me and then began walking into the Park. +I slipped out, put on my things, and followed him. Some woman +came talking something or other about Lord St. Simon to +me--seemed to me from the little I heard as if he had a little +secret of his own before marriage also--but I managed to get away +from her and soon overtook Frank. We got into a cab together, and +away we drove to some lodgings he had taken in Gordon Square, and +that was my true wedding after all those years of waiting. Frank +had been a prisoner among the Apaches, had escaped, came on to +'Frisco, found that I had given him up for dead and had gone to +England, followed me there, and had come upon me at last on the +very morning of my second wedding." + +"I saw it in a paper," explained the American. "It gave the name +and the church but not where the lady lived." + +"Then we had a talk as to what we should do, and Frank was all +for openness, but I was so ashamed of it all that I felt as if I +should like to vanish away and never see any of them again--just +sending a line to pa, perhaps, to show him that I was alive. It +was awful to me to think of all those lords and ladies sitting +round that breakfast-table and waiting for me to come back. So +Frank took my wedding-clothes and things and made a bundle of +them, so that I should not be traced, and dropped them away +somewhere where no one could find them. It is likely that we +should have gone on to Paris to-morrow, only that this good +gentleman, Mr. Holmes, came round to us this evening, though how +he found us is more than I can think, and he showed us very +clearly and kindly that I was wrong and that Frank was right, and +that we should be putting ourselves in the wrong if we were so +secret. Then he offered to give us a chance of talking to Lord +St. Simon alone, and so we came right away round to his rooms at +once. Now, Robert, you have heard it all, and I am very sorry if +I have given you pain, and I hope that you do not think very +meanly of me." + +Lord St. Simon had by no means relaxed his rigid attitude, but +had listened with a frowning brow and a compressed lip to this +long narrative. + +"Excuse me," he said, "but it is not my custom to discuss my most +intimate personal affairs in this public manner." + +"Then you won't forgive me? You won't shake hands before I go?" + +"Oh, certainly, if it would give you any pleasure." He put out +his hand and coldly grasped that which she extended to him. + +"I had hoped," suggested Holmes, "that you would have joined us +in a friendly supper." + +"I think that there you ask a little too much," responded his +Lordship. "I may be forced to acquiesce in these recent +developments, but I can hardly be expected to make merry over +them. I think that with your permission I will now wish you all a +very good-night." He included us all in a sweeping bow and +stalked out of the room. + +"Then I trust that you at least will honour me with your +company," said Sherlock Holmes. "It is always a joy to meet an +American, Mr. Moulton, for I am one of those who believe that the +folly of a monarch and the blundering of a minister in far-gone +years will not prevent our children from being some day citizens +of the same world-wide country under a flag which shall be a +quartering of the Union Jack with the Stars and Stripes." + +"The case has been an interesting one," remarked Holmes when our +visitors had left us, "because it serves to show very clearly how +simple the explanation may be of an affair which at first sight +seems to be almost inexplicable. Nothing could be more natural +than the sequence of events as narrated by this lady, and nothing +stranger than the result when viewed, for instance, by Mr. +Lestrade of Scotland Yard." + +"You were not yourself at fault at all, then?" + +"From the first, two facts were very obvious to me, the one that +the lady had been quite willing to undergo the wedding ceremony, +the other that she had repented of it within a few minutes of +returning home. Obviously something had occurred during the +morning, then, to cause her to change her mind. What could that +something be? She could not have spoken to anyone when she was +out, for she had been in the company of the bridegroom. Had she +seen someone, then? If she had, it must be someone from America +because she had spent so short a time in this country that she +could hardly have allowed anyone to acquire so deep an influence +over her that the mere sight of him would induce her to change +her plans so completely. You see we have already arrived, by a +process of exclusion, at the idea that she might have seen an +American. Then who could this American be, and why should he +possess so much influence over her? It might be a lover; it might +be a husband. Her young womanhood had, I knew, been spent in +rough scenes and under strange conditions. So far I had got +before I ever heard Lord St. Simon's narrative. When he told us +of a man in a pew, of the change in the bride's manner, of so +transparent a device for obtaining a note as the dropping of a +bouquet, of her resort to her confidential maid, and of her very +significant allusion to claim-jumping--which in miners' parlance +means taking possession of that which another person has a prior +claim to--the whole situation became absolutely clear. She had +gone off with a man, and the man was either a lover or was a +previous husband--the chances being in favour of the latter." + +"And how in the world did you find them?" + +"It might have been difficult, but friend Lestrade held +information in his hands the value of which he did not himself +know. The initials were, of course, of the highest importance, +but more valuable still was it to know that within a week he had +settled his bill at one of the most select London hotels." + +"How did you deduce the select?" + +"By the select prices. Eight shillings for a bed and eightpence +for a glass of sherry pointed to one of the most expensive +hotels. There are not many in London which charge at that rate. +In the second one which I visited in Northumberland Avenue, I +learned by an inspection of the book that Francis H. Moulton, an +American gentleman, had left only the day before, and on looking +over the entries against him, I came upon the very items which I +had seen in the duplicate bill. His letters were to be forwarded +to 226 Gordon Square; so thither I travelled, and being fortunate +enough to find the loving couple at home, I ventured to give them +some paternal advice and to point out to them that it would be +better in every way that they should make their position a little +clearer both to the general public and to Lord St. Simon in +particular. I invited them to meet him here, and, as you see, I +made him keep the appointment." + +"But with no very good result," I remarked. "His conduct was +certainly not very gracious." + +"Ah, Watson," said Holmes, smiling, "perhaps you would not be +very gracious either, if, after all the trouble of wooing and +wedding, you found yourself deprived in an instant of wife and of +fortune. I think that we may judge Lord St. Simon very mercifully +and thank our stars that we are never likely to find ourselves in +the same position. Draw your chair up and hand me my violin, for +the only problem we have still to solve is how to while away +these bleak autumnal evenings." + + + +XI. THE ADVENTURE OF THE BERYL CORONET + +"Holmes," said I as I stood one morning in our bow-window looking +down the street, "here is a madman coming along. It seems rather +sad that his relatives should allow him to come out alone." + +My friend rose lazily from his armchair and stood with his hands +in the pockets of his dressing-gown, looking over my shoulder. It +was a bright, crisp February morning, and the snow of the day +before still lay deep upon the ground, shimmering brightly in the +wintry sun. Down the centre of Baker Street it had been ploughed +into a brown crumbly band by the traffic, but at either side and +on the heaped-up edges of the foot-paths it still lay as white as +when it fell. The grey pavement had been cleaned and scraped, but +was still dangerously slippery, so that there were fewer +passengers than usual. Indeed, from the direction of the +Metropolitan Station no one was coming save the single gentleman +whose eccentric conduct had drawn my attention. + +He was a man of about fifty, tall, portly, and imposing, with a +massive, strongly marked face and a commanding figure. He was +dressed in a sombre yet rich style, in black frock-coat, shining +hat, neat brown gaiters, and well-cut pearl-grey trousers. Yet +his actions were in absurd contrast to the dignity of his dress +and features, for he was running hard, with occasional little +springs, such as a weary man gives who is little accustomed to +set any tax upon his legs. As he ran he jerked his hands up and +down, waggled his head, and writhed his face into the most +extraordinary contortions. + +"What on earth can be the matter with him?" I asked. "He is +looking up at the numbers of the houses." + +"I believe that he is coming here," said Holmes, rubbing his +hands. + +"Here?" + +"Yes; I rather think he is coming to consult me professionally. I +think that I recognise the symptoms. Ha! did I not tell you?" As +he spoke, the man, puffing and blowing, rushed at our door and +pulled at our bell until the whole house resounded with the +clanging. + +A few moments later he was in our room, still puffing, still +gesticulating, but with so fixed a look of grief and despair in +his eyes that our smiles were turned in an instant to horror and +pity. For a while he could not get his words out, but swayed his +body and plucked at his hair like one who has been driven to the +extreme limits of his reason. Then, suddenly springing to his +feet, he beat his head against the wall with such force that we +both rushed upon him and tore him away to the centre of the room. +Sherlock Holmes pushed him down into the easy-chair and, sitting +beside him, patted his hand and chatted with him in the easy, +soothing tones which he knew so well how to employ. + +"You have come to me to tell your story, have you not?" said he. +"You are fatigued with your haste. Pray wait until you have +recovered yourself, and then I shall be most happy to look into +any little problem which you may submit to me." + +The man sat for a minute or more with a heaving chest, fighting +against his emotion. Then he passed his handkerchief over his +brow, set his lips tight, and turned his face towards us. + +"No doubt you think me mad?" said he. + +"I see that you have had some great trouble," responded Holmes. + +"God knows I have!--a trouble which is enough to unseat my +reason, so sudden and so terrible is it. Public disgrace I might +have faced, although I am a man whose character has never yet +borne a stain. Private affliction also is the lot of every man; +but the two coming together, and in so frightful a form, have +been enough to shake my very soul. Besides, it is not I alone. +The very noblest in the land may suffer unless some way be found +out of this horrible affair." + +"Pray compose yourself, sir," said Holmes, "and let me have a +clear account of who you are and what it is that has befallen +you." + +"My name," answered our visitor, "is probably familiar to your +ears. I am Alexander Holder, of the banking firm of Holder & +Stevenson, of Threadneedle Street." + +The name was indeed well known to us as belonging to the senior +partner in the second largest private banking concern in the City +of London. What could have happened, then, to bring one of the +foremost citizens of London to this most pitiable pass? We +waited, all curiosity, until with another effort he braced +himself to tell his story. + +"I feel that time is of value," said he; "that is why I hastened +here when the police inspector suggested that I should secure +your co-operation. I came to Baker Street by the Underground and +hurried from there on foot, for the cabs go slowly through this +snow. That is why I was so out of breath, for I am a man who +takes very little exercise. I feel better now, and I will put the +facts before you as shortly and yet as clearly as I can. + +"It is, of course, well known to you that in a successful banking +business as much depends upon our being able to find remunerative +investments for our funds as upon our increasing our connection +and the number of our depositors. One of our most lucrative means +of laying out money is in the shape of loans, where the security +is unimpeachable. We have done a good deal in this direction +during the last few years, and there are many noble families to +whom we have advanced large sums upon the security of their +pictures, libraries, or plate. + +"Yesterday morning I was seated in my office at the bank when a +card was brought in to me by one of the clerks. I started when I +saw the name, for it was that of none other than--well, perhaps +even to you I had better say no more than that it was a name +which is a household word all over the earth--one of the highest, +noblest, most exalted names in England. I was overwhelmed by the +honour and attempted, when he entered, to say so, but he plunged +at once into business with the air of a man who wishes to hurry +quickly through a disagreeable task. + +"'Mr. Holder,' said he, 'I have been informed that you are in the +habit of advancing money.' + +"'The firm does so when the security is good.' I answered. + +"'It is absolutely essential to me,' said he, 'that I should have +50,000 pounds at once. I could, of course, borrow so trifling a +sum ten times over from my friends, but I much prefer to make it +a matter of business and to carry out that business myself. In my +position you can readily understand that it is unwise to place +one's self under obligations.' + +"'For how long, may I ask, do you want this sum?' I asked. + +"'Next Monday I have a large sum due to me, and I shall then most +certainly repay what you advance, with whatever interest you +think it right to charge. But it is very essential to me that the +money should be paid at once.' + +"'I should be happy to advance it without further parley from my +own private purse,' said I, 'were it not that the strain would be +rather more than it could bear. If, on the other hand, I am to do +it in the name of the firm, then in justice to my partner I must +insist that, even in your case, every businesslike precaution +should be taken.' + +"'I should much prefer to have it so,' said he, raising up a +square, black morocco case which he had laid beside his chair. +'You have doubtless heard of the Beryl Coronet?' + +"'One of the most precious public possessions of the empire,' +said I. + +"'Precisely.' He opened the case, and there, imbedded in soft, +flesh-coloured velvet, lay the magnificent piece of jewellery +which he had named. 'There are thirty-nine enormous beryls,' said +he, 'and the price of the gold chasing is incalculable. The +lowest estimate would put the worth of the coronet at double the +sum which I have asked. I am prepared to leave it with you as my +security.' + +"I took the precious case into my hands and looked in some +perplexity from it to my illustrious client. + +"'You doubt its value?' he asked. + +"'Not at all. I only doubt--' + +"'The propriety of my leaving it. You may set your mind at rest +about that. I should not dream of doing so were it not absolutely +certain that I should be able in four days to reclaim it. It is a +pure matter of form. Is the security sufficient?' + +"'Ample.' + +"'You understand, Mr. Holder, that I am giving you a strong proof +of the confidence which I have in you, founded upon all that I +have heard of you. I rely upon you not only to be discreet and to +refrain from all gossip upon the matter but, above all, to +preserve this coronet with every possible precaution because I +need not say that a great public scandal would be caused if any +harm were to befall it. Any injury to it would be almost as +serious as its complete loss, for there are no beryls in the +world to match these, and it would be impossible to replace them. +I leave it with you, however, with every confidence, and I shall +call for it in person on Monday morning.' + +"Seeing that my client was anxious to leave, I said no more but, +calling for my cashier, I ordered him to pay over fifty 1000 +pound notes. When I was alone once more, however, with the +precious case lying upon the table in front of me, I could not +but think with some misgivings of the immense responsibility +which it entailed upon me. There could be no doubt that, as it +was a national possession, a horrible scandal would ensue if any +misfortune should occur to it. I already regretted having ever +consented to take charge of it. However, it was too late to alter +the matter now, so I locked it up in my private safe and turned +once more to my work. + +"When evening came I felt that it would be an imprudence to leave +so precious a thing in the office behind me. Bankers' safes had +been forced before now, and why should not mine be? If so, how +terrible would be the position in which I should find myself! I +determined, therefore, that for the next few days I would always +carry the case backward and forward with me, so that it might +never be really out of my reach. With this intention, I called a +cab and drove out to my house at Streatham, carrying the jewel +with me. I did not breathe freely until I had taken it upstairs +and locked it in the bureau of my dressing-room. + +"And now a word as to my household, Mr. Holmes, for I wish you to +thoroughly understand the situation. My groom and my page sleep +out of the house, and may be set aside altogether. I have three +maid-servants who have been with me a number of years and whose +absolute reliability is quite above suspicion. Another, Lucy +Parr, the second waiting-maid, has only been in my service a few +months. She came with an excellent character, however, and has +always given me satisfaction. She is a very pretty girl and has +attracted admirers who have occasionally hung about the place. +That is the only drawback which we have found to her, but we +believe her to be a thoroughly good girl in every way. + +"So much for the servants. My family itself is so small that it +will not take me long to describe it. I am a widower and have an +only son, Arthur. He has been a disappointment to me, Mr. +Holmes--a grievous disappointment. I have no doubt that I am +myself to blame. People tell me that I have spoiled him. Very +likely I have. When my dear wife died I felt that he was all I +had to love. I could not bear to see the smile fade even for a +moment from his face. I have never denied him a wish. Perhaps it +would have been better for both of us had I been sterner, but I +meant it for the best. + +"It was naturally my intention that he should succeed me in my +business, but he was not of a business turn. He was wild, +wayward, and, to speak the truth, I could not trust him in the +handling of large sums of money. When he was young he became a +member of an aristocratic club, and there, having charming +manners, he was soon the intimate of a number of men with long +purses and expensive habits. He learned to play heavily at cards +and to squander money on the turf, until he had again and again +to come to me and implore me to give him an advance upon his +allowance, that he might settle his debts of honour. He tried +more than once to break away from the dangerous company which he +was keeping, but each time the influence of his friend, Sir +George Burnwell, was enough to draw him back again. + +"And, indeed, I could not wonder that such a man as Sir George +Burnwell should gain an influence over him, for he has frequently +brought him to my house, and I have found myself that I could +hardly resist the fascination of his manner. He is older than +Arthur, a man of the world to his finger-tips, one who had been +everywhere, seen everything, a brilliant talker, and a man of +great personal beauty. Yet when I think of him in cold blood, far +away from the glamour of his presence, I am convinced from his +cynical speech and the look which I have caught in his eyes that +he is one who should be deeply distrusted. So I think, and so, +too, thinks my little Mary, who has a woman's quick insight into +character. + +"And now there is only she to be described. She is my niece; but +when my brother died five years ago and left her alone in the +world I adopted her, and have looked upon her ever since as my +daughter. She is a sunbeam in my house--sweet, loving, beautiful, +a wonderful manager and housekeeper, yet as tender and quiet and +gentle as a woman could be. She is my right hand. I do not know +what I could do without her. In only one matter has she ever gone +against my wishes. Twice my boy has asked her to marry him, for +he loves her devotedly, but each time she has refused him. I +think that if anyone could have drawn him into the right path it +would have been she, and that his marriage might have changed his +whole life; but now, alas! it is too late--forever too late! + +"Now, Mr. Holmes, you know the people who live under my roof, and +I shall continue with my miserable story. + +"When we were taking coffee in the drawing-room that night after +dinner, I told Arthur and Mary my experience, and of the precious +treasure which we had under our roof, suppressing only the name +of my client. Lucy Parr, who had brought in the coffee, had, I am +sure, left the room; but I cannot swear that the door was closed. +Mary and Arthur were much interested and wished to see the famous +coronet, but I thought it better not to disturb it. + +"'Where have you put it?' asked Arthur. + +"'In my own bureau.' + +"'Well, I hope to goodness the house won't be burgled during the +night.' said he. + +"'It is locked up,' I answered. + +"'Oh, any old key will fit that bureau. When I was a youngster I +have opened it myself with the key of the box-room cupboard.' + +"He often had a wild way of talking, so that I thought little of +what he said. He followed me to my room, however, that night with +a very grave face. + +"'Look here, dad,' said he with his eyes cast down, 'can you let +me have 200 pounds?' + +"'No, I cannot!' I answered sharply. 'I have been far too +generous with you in money matters.' + +"'You have been very kind,' said he, 'but I must have this money, +or else I can never show my face inside the club again.' + +"'And a very good thing, too!' I cried. + +"'Yes, but you would not have me leave it a dishonoured man,' +said he. 'I could not bear the disgrace. I must raise the money +in some way, and if you will not let me have it, then I must try +other means.' + +"I was very angry, for this was the third demand during the +month. 'You shall not have a farthing from me,' I cried, on which +he bowed and left the room without another word. + +"When he was gone I unlocked my bureau, made sure that my +treasure was safe, and locked it again. Then I started to go +round the house to see that all was secure--a duty which I +usually leave to Mary but which I thought it well to perform +myself that night. As I came down the stairs I saw Mary herself +at the side window of the hall, which she closed and fastened as +I approached. + +"'Tell me, dad,' said she, looking, I thought, a little +disturbed, 'did you give Lucy, the maid, leave to go out +to-night?' + +"'Certainly not.' + +"'She came in just now by the back door. I have no doubt that she +has only been to the side gate to see someone, but I think that +it is hardly safe and should be stopped.' + +"'You must speak to her in the morning, or I will if you prefer +it. Are you sure that everything is fastened?' + +"'Quite sure, dad.' + +"'Then, good-night.' I kissed her and went up to my bedroom +again, where I was soon asleep. + +"I am endeavouring to tell you everything, Mr. Holmes, which may +have any bearing upon the case, but I beg that you will question +me upon any point which I do not make clear." + +"On the contrary, your statement is singularly lucid." + +"I come to a part of my story now in which I should wish to be +particularly so. I am not a very heavy sleeper, and the anxiety +in my mind tended, no doubt, to make me even less so than usual. +About two in the morning, then, I was awakened by some sound in +the house. It had ceased ere I was wide awake, but it had left an +impression behind it as though a window had gently closed +somewhere. I lay listening with all my ears. Suddenly, to my +horror, there was a distinct sound of footsteps moving softly in +the next room. I slipped out of bed, all palpitating with fear, +and peeped round the corner of my dressing-room door. + +"'Arthur!' I screamed, 'you villain! you thief! How dare you +touch that coronet?' + +"The gas was half up, as I had left it, and my unhappy boy, +dressed only in his shirt and trousers, was standing beside the +light, holding the coronet in his hands. He appeared to be +wrenching at it, or bending it with all his strength. At my cry +he dropped it from his grasp and turned as pale as death. I +snatched it up and examined it. One of the gold corners, with +three of the beryls in it, was missing. + +"'You blackguard!' I shouted, beside myself with rage. 'You have +destroyed it! You have dishonoured me forever! Where are the +jewels which you have stolen?' + +"'Stolen!' he cried. + +"'Yes, thief!' I roared, shaking him by the shoulder. + +"'There are none missing. There cannot be any missing,' said he. + +"'There are three missing. And you know where they are. Must I +call you a liar as well as a thief? Did I not see you trying to +tear off another piece?' + +"'You have called me names enough,' said he, 'I will not stand it +any longer. I shall not say another word about this business, +since you have chosen to insult me. I will leave your house in +the morning and make my own way in the world.' + +"'You shall leave it in the hands of the police!' I cried +half-mad with grief and rage. 'I shall have this matter probed to +the bottom.' + +"'You shall learn nothing from me,' said he with a passion such +as I should not have thought was in his nature. 'If you choose to +call the police, let the police find what they can.' + +"By this time the whole house was astir, for I had raised my +voice in my anger. Mary was the first to rush into my room, and, +at the sight of the coronet and of Arthur's face, she read the +whole story and, with a scream, fell down senseless on the +ground. I sent the house-maid for the police and put the +investigation into their hands at once. When the inspector and a +constable entered the house, Arthur, who had stood sullenly with +his arms folded, asked me whether it was my intention to charge +him with theft. I answered that it had ceased to be a private +matter, but had become a public one, since the ruined coronet was +national property. I was determined that the law should have its +way in everything. + +"'At least,' said he, 'you will not have me arrested at once. It +would be to your advantage as well as mine if I might leave the +house for five minutes.' + +"'That you may get away, or perhaps that you may conceal what you +have stolen,' said I. And then, realising the dreadful position +in which I was placed, I implored him to remember that not only +my honour but that of one who was far greater than I was at +stake; and that he threatened to raise a scandal which would +convulse the nation. He might avert it all if he would but tell +me what he had done with the three missing stones. + +"'You may as well face the matter,' said I; 'you have been caught +in the act, and no confession could make your guilt more heinous. +If you but make such reparation as is in your power, by telling +us where the beryls are, all shall be forgiven and forgotten.' + +"'Keep your forgiveness for those who ask for it,' he answered, +turning away from me with a sneer. I saw that he was too hardened +for any words of mine to influence him. There was but one way for +it. I called in the inspector and gave him into custody. A search +was made at once not only of his person but of his room and of +every portion of the house where he could possibly have concealed +the gems; but no trace of them could be found, nor would the +wretched boy open his mouth for all our persuasions and our +threats. This morning he was removed to a cell, and I, after +going through all the police formalities, have hurried round to +you to implore you to use your skill in unravelling the matter. +The police have openly confessed that they can at present make +nothing of it. You may go to any expense which you think +necessary. I have already offered a reward of 1000 pounds. My +God, what shall I do! I have lost my honour, my gems, and my son +in one night. Oh, what shall I do!" + +He put a hand on either side of his head and rocked himself to +and fro, droning to himself like a child whose grief has got +beyond words. + +Sherlock Holmes sat silent for some few minutes, with his brows +knitted and his eyes fixed upon the fire. + +"Do you receive much company?" he asked. + +"None save my partner with his family and an occasional friend of +Arthur's. Sir George Burnwell has been several times lately. No +one else, I think." + +"Do you go out much in society?" + +"Arthur does. Mary and I stay at home. We neither of us care for +it." + +"That is unusual in a young girl." + +"She is of a quiet nature. Besides, she is not so very young. She +is four-and-twenty." + +"This matter, from what you say, seems to have been a shock to +her also." + +"Terrible! She is even more affected than I." + +"You have neither of you any doubt as to your son's guilt?" + +"How can we have when I saw him with my own eyes with the coronet +in his hands." + +"I hardly consider that a conclusive proof. Was the remainder of +the coronet at all injured?" + +"Yes, it was twisted." + +"Do you not think, then, that he might have been trying to +straighten it?" + +"God bless you! You are doing what you can for him and for me. +But it is too heavy a task. What was he doing there at all? If +his purpose were innocent, why did he not say so?" + +"Precisely. And if it were guilty, why did he not invent a lie? +His silence appears to me to cut both ways. There are several +singular points about the case. What did the police think of the +noise which awoke you from your sleep?" + +"They considered that it might be caused by Arthur's closing his +bedroom door." + +"A likely story! As if a man bent on felony would slam his door +so as to wake a household. What did they say, then, of the +disappearance of these gems?" + +"They are still sounding the planking and probing the furniture +in the hope of finding them." + +"Have they thought of looking outside the house?" + +"Yes, they have shown extraordinary energy. The whole garden has +already been minutely examined." + +"Now, my dear sir," said Holmes, "is it not obvious to you now +that this matter really strikes very much deeper than either you +or the police were at first inclined to think? It appeared to you +to be a simple case; to me it seems exceedingly complex. Consider +what is involved by your theory. You suppose that your son came +down from his bed, went, at great risk, to your dressing-room, +opened your bureau, took out your coronet, broke off by main +force a small portion of it, went off to some other place, +concealed three gems out of the thirty-nine, with such skill that +nobody can find them, and then returned with the other thirty-six +into the room in which he exposed himself to the greatest danger +of being discovered. I ask you now, is such a theory tenable?" + +"But what other is there?" cried the banker with a gesture of +despair. "If his motives were innocent, why does he not explain +them?" + +"It is our task to find that out," replied Holmes; "so now, if +you please, Mr. Holder, we will set off for Streatham together, +and devote an hour to glancing a little more closely into +details." + +My friend insisted upon my accompanying them in their expedition, +which I was eager enough to do, for my curiosity and sympathy +were deeply stirred by the story to which we had listened. I +confess that the guilt of the banker's son appeared to me to be +as obvious as it did to his unhappy father, but still I had such +faith in Holmes' judgment that I felt that there must be some +grounds for hope as long as he was dissatisfied with the accepted +explanation. He hardly spoke a word the whole way out to the +southern suburb, but sat with his chin upon his breast and his +hat drawn over his eyes, sunk in the deepest thought. Our client +appeared to have taken fresh heart at the little glimpse of hope +which had been presented to him, and he even broke into a +desultory chat with me over his business affairs. A short railway +journey and a shorter walk brought us to Fairbank, the modest +residence of the great financier. + +Fairbank was a good-sized square house of white stone, standing +back a little from the road. A double carriage-sweep, with a +snow-clad lawn, stretched down in front to two large iron gates +which closed the entrance. On the right side was a small wooden +thicket, which led into a narrow path between two neat hedges +stretching from the road to the kitchen door, and forming the +tradesmen's entrance. On the left ran a lane which led to the +stables, and was not itself within the grounds at all, being a +public, though little used, thoroughfare. Holmes left us standing +at the door and walked slowly all round the house, across the +front, down the tradesmen's path, and so round by the garden +behind into the stable lane. So long was he that Mr. Holder and I +went into the dining-room and waited by the fire until he should +return. We were sitting there in silence when the door opened and +a young lady came in. She was rather above the middle height, +slim, with dark hair and eyes, which seemed the darker against +the absolute pallor of her skin. I do not think that I have ever +seen such deadly paleness in a woman's face. Her lips, too, were +bloodless, but her eyes were flushed with crying. As she swept +silently into the room she impressed me with a greater sense of +grief than the banker had done in the morning, and it was the +more striking in her as she was evidently a woman of strong +character, with immense capacity for self-restraint. Disregarding +my presence, she went straight to her uncle and passed her hand +over his head with a sweet womanly caress. + +"You have given orders that Arthur should be liberated, have you +not, dad?" she asked. + +"No, no, my girl, the matter must be probed to the bottom." + +"But I am so sure that he is innocent. You know what woman's +instincts are. I know that he has done no harm and that you will +be sorry for having acted so harshly." + +"Why is he silent, then, if he is innocent?" + +"Who knows? Perhaps because he was so angry that you should +suspect him." + +"How could I help suspecting him, when I actually saw him with +the coronet in his hand?" + +"Oh, but he had only picked it up to look at it. Oh, do, do take +my word for it that he is innocent. Let the matter drop and say +no more. It is so dreadful to think of our dear Arthur in +prison!" + +"I shall never let it drop until the gems are found--never, Mary! +Your affection for Arthur blinds you as to the awful consequences +to me. Far from hushing the thing up, I have brought a gentleman +down from London to inquire more deeply into it." + +"This gentleman?" she asked, facing round to me. + +"No, his friend. He wished us to leave him alone. He is round in +the stable lane now." + +"The stable lane?" She raised her dark eyebrows. "What can he +hope to find there? Ah! this, I suppose, is he. I trust, sir, +that you will succeed in proving, what I feel sure is the truth, +that my cousin Arthur is innocent of this crime." + +"I fully share your opinion, and I trust, with you, that we may +prove it," returned Holmes, going back to the mat to knock the +snow from his shoes. "I believe I have the honour of addressing +Miss Mary Holder. Might I ask you a question or two?" + +"Pray do, sir, if it may help to clear this horrible affair up." + +"You heard nothing yourself last night?" + +"Nothing, until my uncle here began to speak loudly. I heard +that, and I came down." + +"You shut up the windows and doors the night before. Did you +fasten all the windows?" + +"Yes." + +"Were they all fastened this morning?" + +"Yes." + +"You have a maid who has a sweetheart? I think that you remarked +to your uncle last night that she had been out to see him?" + +"Yes, and she was the girl who waited in the drawing-room, and +who may have heard uncle's remarks about the coronet." + +"I see. You infer that she may have gone out to tell her +sweetheart, and that the two may have planned the robbery." + +"But what is the good of all these vague theories," cried the +banker impatiently, "when I have told you that I saw Arthur with +the coronet in his hands?" + +"Wait a little, Mr. Holder. We must come back to that. About this +girl, Miss Holder. You saw her return by the kitchen door, I +presume?" + +"Yes; when I went to see if the door was fastened for the night I +met her slipping in. I saw the man, too, in the gloom." + +"Do you know him?" + +"Oh, yes! he is the green-grocer who brings our vegetables round. +His name is Francis Prosper." + +"He stood," said Holmes, "to the left of the door--that is to +say, farther up the path than is necessary to reach the door?" + +"Yes, he did." + +"And he is a man with a wooden leg?" + +Something like fear sprang up in the young lady's expressive +black eyes. "Why, you are like a magician," said she. "How do you +know that?" She smiled, but there was no answering smile in +Holmes' thin, eager face. + +"I should be very glad now to go upstairs," said he. "I shall +probably wish to go over the outside of the house again. Perhaps +I had better take a look at the lower windows before I go up." + +He walked swiftly round from one to the other, pausing only at +the large one which looked from the hall onto the stable lane. +This he opened and made a very careful examination of the sill +with his powerful magnifying lens. "Now we shall go upstairs," +said he at last. + +The banker's dressing-room was a plainly furnished little +chamber, with a grey carpet, a large bureau, and a long mirror. +Holmes went to the bureau first and looked hard at the lock. + +"Which key was used to open it?" he asked. + +"That which my son himself indicated--that of the cupboard of the +lumber-room." + +"Have you it here?" + +"That is it on the dressing-table." + +Sherlock Holmes took it up and opened the bureau. + +"It is a noiseless lock," said he. "It is no wonder that it did +not wake you. This case, I presume, contains the coronet. We must +have a look at it." He opened the case, and taking out the diadem +he laid it upon the table. It was a magnificent specimen of the +jeweller's art, and the thirty-six stones were the finest that I +have ever seen. At one side of the coronet was a cracked edge, +where a corner holding three gems had been torn away. + +"Now, Mr. Holder," said Holmes, "here is the corner which +corresponds to that which has been so unfortunately lost. Might I +beg that you will break it off." + +The banker recoiled in horror. "I should not dream of trying," +said he. + +"Then I will." Holmes suddenly bent his strength upon it, but +without result. "I feel it give a little," said he; "but, though +I am exceptionally strong in the fingers, it would take me all my +time to break it. An ordinary man could not do it. Now, what do +you think would happen if I did break it, Mr. Holder? There would +be a noise like a pistol shot. Do you tell me that all this +happened within a few yards of your bed and that you heard +nothing of it?" + +"I do not know what to think. It is all dark to me." + +"But perhaps it may grow lighter as we go. What do you think, +Miss Holder?" + +"I confess that I still share my uncle's perplexity." + +"Your son had no shoes or slippers on when you saw him?" + +"He had nothing on save only his trousers and shirt." + +"Thank you. We have certainly been favoured with extraordinary +luck during this inquiry, and it will be entirely our own fault +if we do not succeed in clearing the matter up. With your +permission, Mr. Holder, I shall now continue my investigations +outside." + +He went alone, at his own request, for he explained that any +unnecessary footmarks might make his task more difficult. For an +hour or more he was at work, returning at last with his feet +heavy with snow and his features as inscrutable as ever. + +"I think that I have seen now all that there is to see, Mr. +Holder," said he; "I can serve you best by returning to my +rooms." + +"But the gems, Mr. Holmes. Where are they?" + +"I cannot tell." + +The banker wrung his hands. "I shall never see them again!" he +cried. "And my son? You give me hopes?" + +"My opinion is in no way altered." + +"Then, for God's sake, what was this dark business which was +acted in my house last night?" + +"If you can call upon me at my Baker Street rooms to-morrow +morning between nine and ten I shall be happy to do what I can to +make it clearer. I understand that you give me carte blanche to +act for you, provided only that I get back the gems, and that you +place no limit on the sum I may draw." + +"I would give my fortune to have them back." + +"Very good. I shall look into the matter between this and then. +Good-bye; it is just possible that I may have to come over here +again before evening." + +It was obvious to me that my companion's mind was now made up +about the case, although what his conclusions were was more than +I could even dimly imagine. Several times during our homeward +journey I endeavoured to sound him upon the point, but he always +glided away to some other topic, until at last I gave it over in +despair. It was not yet three when we found ourselves in our +rooms once more. He hurried to his chamber and was down again in +a few minutes dressed as a common loafer. With his collar turned +up, his shiny, seedy coat, his red cravat, and his worn boots, he +was a perfect sample of the class. + +"I think that this should do," said he, glancing into the glass +above the fireplace. "I only wish that you could come with me, +Watson, but I fear that it won't do. I may be on the trail in +this matter, or I may be following a will-o'-the-wisp, but I +shall soon know which it is. I hope that I may be back in a few +hours." He cut a slice of beef from the joint upon the sideboard, +sandwiched it between two rounds of bread, and thrusting this +rude meal into his pocket he started off upon his expedition. + +I had just finished my tea when he returned, evidently in +excellent spirits, swinging an old elastic-sided boot in his +hand. He chucked it down into a corner and helped himself to a +cup of tea. + +"I only looked in as I passed," said he. "I am going right on." + +"Where to?" + +"Oh, to the other side of the West End. It may be some time +before I get back. Don't wait up for me in case I should be +late." + +"How are you getting on?" + +"Oh, so so. Nothing to complain of. I have been out to Streatham +since I saw you last, but I did not call at the house. It is a +very sweet little problem, and I would not have missed it for a +good deal. However, I must not sit gossiping here, but must get +these disreputable clothes off and return to my highly +respectable self." + +I could see by his manner that he had stronger reasons for +satisfaction than his words alone would imply. His eyes twinkled, +and there was even a touch of colour upon his sallow cheeks. He +hastened upstairs, and a few minutes later I heard the slam of +the hall door, which told me that he was off once more upon his +congenial hunt. + +I waited until midnight, but there was no sign of his return, so +I retired to my room. It was no uncommon thing for him to be away +for days and nights on end when he was hot upon a scent, so that +his lateness caused me no surprise. I do not know at what hour he +came in, but when I came down to breakfast in the morning there +he was with a cup of coffee in one hand and the paper in the +other, as fresh and trim as possible. + +"You will excuse my beginning without you, Watson," said he, "but +you remember that our client has rather an early appointment this +morning." + +"Why, it is after nine now," I answered. "I should not be +surprised if that were he. I thought I heard a ring." + +It was, indeed, our friend the financier. I was shocked by the +change which had come over him, for his face which was naturally +of a broad and massive mould, was now pinched and fallen in, +while his hair seemed to me at least a shade whiter. He entered +with a weariness and lethargy which was even more painful than +his violence of the morning before, and he dropped heavily into +the armchair which I pushed forward for him. + +"I do not know what I have done to be so severely tried," said +he. "Only two days ago I was a happy and prosperous man, without +a care in the world. Now I am left to a lonely and dishonoured +age. One sorrow comes close upon the heels of another. My niece, +Mary, has deserted me." + +"Deserted you?" + +"Yes. Her bed this morning had not been slept in, her room was +empty, and a note for me lay upon the hall table. I had said to +her last night, in sorrow and not in anger, that if she had +married my boy all might have been well with him. Perhaps it was +thoughtless of me to say so. It is to that remark that she refers +in this note: + +"'MY DEAREST UNCLE:--I feel that I have brought trouble upon you, +and that if I had acted differently this terrible misfortune +might never have occurred. I cannot, with this thought in my +mind, ever again be happy under your roof, and I feel that I must +leave you forever. Do not worry about my future, for that is +provided for; and, above all, do not search for me, for it will +be fruitless labour and an ill-service to me. In life or in +death, I am ever your loving,--MARY.' + +"What could she mean by that note, Mr. Holmes? Do you think it +points to suicide?" + +"No, no, nothing of the kind. It is perhaps the best possible +solution. I trust, Mr. Holder, that you are nearing the end of +your troubles." + +"Ha! You say so! You have heard something, Mr. Holmes; you have +learned something! Where are the gems?" + +"You would not think 1000 pounds apiece an excessive sum for +them?" + +"I would pay ten." + +"That would be unnecessary. Three thousand will cover the matter. +And there is a little reward, I fancy. Have you your check-book? +Here is a pen. Better make it out for 4000 pounds." + +With a dazed face the banker made out the required check. Holmes +walked over to his desk, took out a little triangular piece of +gold with three gems in it, and threw it down upon the table. + +With a shriek of joy our client clutched it up. + +"You have it!" he gasped. "I am saved! I am saved!" + +The reaction of joy was as passionate as his grief had been, and +he hugged his recovered gems to his bosom. + +"There is one other thing you owe, Mr. Holder," said Sherlock +Holmes rather sternly. + +"Owe!" He caught up a pen. "Name the sum, and I will pay it." + +"No, the debt is not to me. You owe a very humble apology to that +noble lad, your son, who has carried himself in this matter as I +should be proud to see my own son do, should I ever chance to +have one." + +"Then it was not Arthur who took them?" + +"I told you yesterday, and I repeat to-day, that it was not." + +"You are sure of it! Then let us hurry to him at once to let him +know that the truth is known." + +"He knows it already. When I had cleared it all up I had an +interview with him, and finding that he would not tell me the +story, I told it to him, on which he had to confess that I was +right and to add the very few details which were not yet quite +clear to me. Your news of this morning, however, may open his +lips." + +"For heaven's sake, tell me, then, what is this extraordinary +mystery!" + +"I will do so, and I will show you the steps by which I reached +it. And let me say to you, first, that which it is hardest for me +to say and for you to hear: there has been an understanding +between Sir George Burnwell and your niece Mary. They have now +fled together." + +"My Mary? Impossible!" + +"It is unfortunately more than possible; it is certain. Neither +you nor your son knew the true character of this man when you +admitted him into your family circle. He is one of the most +dangerous men in England--a ruined gambler, an absolutely +desperate villain, a man without heart or conscience. Your niece +knew nothing of such men. When he breathed his vows to her, as he +had done to a hundred before her, she flattered herself that she +alone had touched his heart. The devil knows best what he said, +but at least she became his tool and was in the habit of seeing +him nearly every evening." + +"I cannot, and I will not, believe it!" cried the banker with an +ashen face. + +"I will tell you, then, what occurred in your house last night. +Your niece, when you had, as she thought, gone to your room, +slipped down and talked to her lover through the window which +leads into the stable lane. His footmarks had pressed right +through the snow, so long had he stood there. She told him of the +coronet. His wicked lust for gold kindled at the news, and he +bent her to his will. I have no doubt that she loved you, but +there are women in whom the love of a lover extinguishes all +other loves, and I think that she must have been one. She had +hardly listened to his instructions when she saw you coming +downstairs, on which she closed the window rapidly and told you +about one of the servants' escapade with her wooden-legged lover, +which was all perfectly true. + +"Your boy, Arthur, went to bed after his interview with you but +he slept badly on account of his uneasiness about his club debts. +In the middle of the night he heard a soft tread pass his door, +so he rose and, looking out, was surprised to see his cousin +walking very stealthily along the passage until she disappeared +into your dressing-room. Petrified with astonishment, the lad +slipped on some clothes and waited there in the dark to see what +would come of this strange affair. Presently she emerged from the +room again, and in the light of the passage-lamp your son saw +that she carried the precious coronet in her hands. She passed +down the stairs, and he, thrilling with horror, ran along and +slipped behind the curtain near your door, whence he could see +what passed in the hall beneath. He saw her stealthily open the +window, hand out the coronet to someone in the gloom, and then +closing it once more hurry back to her room, passing quite close +to where he stood hid behind the curtain. + +"As long as she was on the scene he could not take any action +without a horrible exposure of the woman whom he loved. But the +instant that she was gone he realised how crushing a misfortune +this would be for you, and how all-important it was to set it +right. He rushed down, just as he was, in his bare feet, opened +the window, sprang out into the snow, and ran down the lane, +where he could see a dark figure in the moonlight. Sir George +Burnwell tried to get away, but Arthur caught him, and there was +a struggle between them, your lad tugging at one side of the +coronet, and his opponent at the other. In the scuffle, your son +struck Sir George and cut him over the eye. Then something +suddenly snapped, and your son, finding that he had the coronet +in his hands, rushed back, closed the window, ascended to your +room, and had just observed that the coronet had been twisted in +the struggle and was endeavouring to straighten it when you +appeared upon the scene." + +"Is it possible?" gasped the banker. + +"You then roused his anger by calling him names at a moment when +he felt that he had deserved your warmest thanks. He could not +explain the true state of affairs without betraying one who +certainly deserved little enough consideration at his hands. He +took the more chivalrous view, however, and preserved her +secret." + +"And that was why she shrieked and fainted when she saw the +coronet," cried Mr. Holder. "Oh, my God! what a blind fool I have +been! And his asking to be allowed to go out for five minutes! +The dear fellow wanted to see if the missing piece were at the +scene of the struggle. How cruelly I have misjudged him!" + +"When I arrived at the house," continued Holmes, "I at once went +very carefully round it to observe if there were any traces in +the snow which might help me. I knew that none had fallen since +the evening before, and also that there had been a strong frost +to preserve impressions. I passed along the tradesmen's path, but +found it all trampled down and indistinguishable. Just beyond it, +however, at the far side of the kitchen door, a woman had stood +and talked with a man, whose round impressions on one side showed +that he had a wooden leg. I could even tell that they had been +disturbed, for the woman had run back swiftly to the door, as was +shown by the deep toe and light heel marks, while Wooden-leg had +waited a little, and then had gone away. I thought at the time +that this might be the maid and her sweetheart, of whom you had +already spoken to me, and inquiry showed it was so. I passed +round the garden without seeing anything more than random tracks, +which I took to be the police; but when I got into the stable +lane a very long and complex story was written in the snow in +front of me. + +"There was a double line of tracks of a booted man, and a second +double line which I saw with delight belonged to a man with naked +feet. I was at once convinced from what you had told me that the +latter was your son. The first had walked both ways, but the +other had run swiftly, and as his tread was marked in places over +the depression of the boot, it was obvious that he had passed +after the other. I followed them up and found they led to the +hall window, where Boots had worn all the snow away while +waiting. Then I walked to the other end, which was a hundred +yards or more down the lane. I saw where Boots had faced round, +where the snow was cut up as though there had been a struggle, +and, finally, where a few drops of blood had fallen, to show me +that I was not mistaken. Boots had then run down the lane, and +another little smudge of blood showed that it was he who had been +hurt. When he came to the highroad at the other end, I found that +the pavement had been cleared, so there was an end to that clue. + +"On entering the house, however, I examined, as you remember, the +sill and framework of the hall window with my lens, and I could +at once see that someone had passed out. I could distinguish the +outline of an instep where the wet foot had been placed in coming +in. I was then beginning to be able to form an opinion as to what +had occurred. A man had waited outside the window; someone had +brought the gems; the deed had been overseen by your son; he had +pursued the thief; had struggled with him; they had each tugged +at the coronet, their united strength causing injuries which +neither alone could have effected. He had returned with the +prize, but had left a fragment in the grasp of his opponent. So +far I was clear. The question now was, who was the man and who +was it brought him the coronet? + +"It is an old maxim of mine that when you have excluded the +impossible, whatever remains, however improbable, must be the +truth. Now, I knew that it was not you who had brought it down, +so there only remained your niece and the maids. But if it were +the maids, why should your son allow himself to be accused in +their place? There could be no possible reason. As he loved his +cousin, however, there was an excellent explanation why he should +retain her secret--the more so as the secret was a disgraceful +one. When I remembered that you had seen her at that window, and +how she had fainted on seeing the coronet again, my conjecture +became a certainty. + +"And who could it be who was her confederate? A lover evidently, +for who else could outweigh the love and gratitude which she must +feel to you? I knew that you went out little, and that your +circle of friends was a very limited one. But among them was Sir +George Burnwell. I had heard of him before as being a man of evil +reputation among women. It must have been he who wore those boots +and retained the missing gems. Even though he knew that Arthur +had discovered him, he might still flatter himself that he was +safe, for the lad could not say a word without compromising his +own family. + +"Well, your own good sense will suggest what measures I took +next. I went in the shape of a loafer to Sir George's house, +managed to pick up an acquaintance with his valet, learned that +his master had cut his head the night before, and, finally, at +the expense of six shillings, made all sure by buying a pair of +his cast-off shoes. With these I journeyed down to Streatham and +saw that they exactly fitted the tracks." + +"I saw an ill-dressed vagabond in the lane yesterday evening," +said Mr. Holder. + +"Precisely. It was I. I found that I had my man, so I came home +and changed my clothes. It was a delicate part which I had to +play then, for I saw that a prosecution must be avoided to avert +scandal, and I knew that so astute a villain would see that our +hands were tied in the matter. I went and saw him. At first, of +course, he denied everything. But when I gave him every +particular that had occurred, he tried to bluster and took down a +life-preserver from the wall. I knew my man, however, and I +clapped a pistol to his head before he could strike. Then he +became a little more reasonable. I told him that we would give +him a price for the stones he held--1000 pounds apiece. That +brought out the first signs of grief that he had shown. 'Why, +dash it all!' said he, 'I've let them go at six hundred for the +three!' I soon managed to get the address of the receiver who had +them, on promising him that there would be no prosecution. Off I +set to him, and after much chaffering I got our stones at 1000 +pounds apiece. Then I looked in upon your son, told him that all +was right, and eventually got to my bed about two o'clock, after +what I may call a really hard day's work." + +"A day which has saved England from a great public scandal," said +the banker, rising. "Sir, I cannot find words to thank you, but +you shall not find me ungrateful for what you have done. Your +skill has indeed exceeded all that I have heard of it. And now I +must fly to my dear boy to apologise to him for the wrong which I +have done him. As to what you tell me of poor Mary, it goes to my +very heart. Not even your skill can inform me where she is now." + +"I think that we may safely say," returned Holmes, "that she is +wherever Sir George Burnwell is. It is equally certain, too, that +whatever her sins are, they will soon receive a more than +sufficient punishment." + + + +XII. THE ADVENTURE OF THE COPPER BEECHES + +"To the man who loves art for its own sake," remarked Sherlock +Holmes, tossing aside the advertisement sheet of the Daily +Telegraph, "it is frequently in its least important and lowliest +manifestations that the keenest pleasure is to be derived. It is +pleasant to me to observe, Watson, that you have so far grasped +this truth that in these little records of our cases which you +have been good enough to draw up, and, I am bound to say, +occasionally to embellish, you have given prominence not so much +to the many causes célèbres and sensational trials in which I +have figured but rather to those incidents which may have been +trivial in themselves, but which have given room for those +faculties of deduction and of logical synthesis which I have made +my special province." + +"And yet," said I, smiling, "I cannot quite hold myself absolved +from the charge of sensationalism which has been urged against my +records." + +"You have erred, perhaps," he observed, taking up a glowing +cinder with the tongs and lighting with it the long cherry-wood +pipe which was wont to replace his clay when he was in a +disputatious rather than a meditative mood--"you have erred +perhaps in attempting to put colour and life into each of your +statements instead of confining yourself to the task of placing +upon record that severe reasoning from cause to effect which is +really the only notable feature about the thing." + +"It seems to me that I have done you full justice in the matter," +I remarked with some coldness, for I was repelled by the egotism +which I had more than once observed to be a strong factor in my +friend's singular character. + +"No, it is not selfishness or conceit," said he, answering, as +was his wont, my thoughts rather than my words. "If I claim full +justice for my art, it is because it is an impersonal thing--a +thing beyond myself. Crime is common. Logic is rare. Therefore it +is upon the logic rather than upon the crime that you should +dwell. You have degraded what should have been a course of +lectures into a series of tales." + +It was a cold morning of the early spring, and we sat after +breakfast on either side of a cheery fire in the old room at +Baker Street. A thick fog rolled down between the lines of +dun-coloured houses, and the opposing windows loomed like dark, +shapeless blurs through the heavy yellow wreaths. Our gas was lit +and shone on the white cloth and glimmer of china and metal, for +the table had not been cleared yet. Sherlock Holmes had been +silent all the morning, dipping continuously into the +advertisement columns of a succession of papers until at last, +having apparently given up his search, he had emerged in no very +sweet temper to lecture me upon my literary shortcomings. + +"At the same time," he remarked after a pause, during which he +had sat puffing at his long pipe and gazing down into the fire, +"you can hardly be open to a charge of sensationalism, for out of +these cases which you have been so kind as to interest yourself +in, a fair proportion do not treat of crime, in its legal sense, +at all. The small matter in which I endeavoured to help the King +of Bohemia, the singular experience of Miss Mary Sutherland, the +problem connected with the man with the twisted lip, and the +incident of the noble bachelor, were all matters which are +outside the pale of the law. But in avoiding the sensational, I +fear that you may have bordered on the trivial." + +"The end may have been so," I answered, "but the methods I hold +to have been novel and of interest." + +"Pshaw, my dear fellow, what do the public, the great unobservant +public, who could hardly tell a weaver by his tooth or a +compositor by his left thumb, care about the finer shades of +analysis and deduction! But, indeed, if you are trivial, I cannot +blame you, for the days of the great cases are past. Man, or at +least criminal man, has lost all enterprise and originality. As +to my own little practice, it seems to be degenerating into an +agency for recovering lost lead pencils and giving advice to +young ladies from boarding-schools. I think that I have touched +bottom at last, however. This note I had this morning marks my +zero-point, I fancy. Read it!" He tossed a crumpled letter across +to me. + +It was dated from Montague Place upon the preceding evening, and +ran thus: + +"DEAR MR. HOLMES:--I am very anxious to consult you as to whether +I should or should not accept a situation which has been offered +to me as governess. I shall call at half-past ten to-morrow if I +do not inconvenience you. Yours faithfully, + "VIOLET HUNTER." + +"Do you know the young lady?" I asked. + +"Not I." + +"It is half-past ten now." + +"Yes, and I have no doubt that is her ring." + +"It may turn out to be of more interest than you think. You +remember that the affair of the blue carbuncle, which appeared to +be a mere whim at first, developed into a serious investigation. +It may be so in this case, also." + +"Well, let us hope so. But our doubts will very soon be solved, +for here, unless I am much mistaken, is the person in question." + +As he spoke the door opened and a young lady entered the room. +She was plainly but neatly dressed, with a bright, quick face, +freckled like a plover's egg, and with the brisk manner of a +woman who has had her own way to make in the world. + +"You will excuse my troubling you, I am sure," said she, as my +companion rose to greet her, "but I have had a very strange +experience, and as I have no parents or relations of any sort +from whom I could ask advice, I thought that perhaps you would be +kind enough to tell me what I should do." + +"Pray take a seat, Miss Hunter. I shall be happy to do anything +that I can to serve you." + +I could see that Holmes was favourably impressed by the manner +and speech of his new client. He looked her over in his searching +fashion, and then composed himself, with his lids drooping and +his finger-tips together, to listen to her story. + +"I have been a governess for five years," said she, "in the +family of Colonel Spence Munro, but two months ago the colonel +received an appointment at Halifax, in Nova Scotia, and took his +children over to America with him, so that I found myself without +a situation. I advertised, and I answered advertisements, but +without success. At last the little money which I had saved began +to run short, and I was at my wit's end as to what I should do. + +"There is a well-known agency for governesses in the West End +called Westaway's, and there I used to call about once a week in +order to see whether anything had turned up which might suit me. +Westaway was the name of the founder of the business, but it is +really managed by Miss Stoper. She sits in her own little office, +and the ladies who are seeking employment wait in an anteroom, +and are then shown in one by one, when she consults her ledgers +and sees whether she has anything which would suit them. + +"Well, when I called last week I was shown into the little office +as usual, but I found that Miss Stoper was not alone. A +prodigiously stout man with a very smiling face and a great heavy +chin which rolled down in fold upon fold over his throat sat at +her elbow with a pair of glasses on his nose, looking very +earnestly at the ladies who entered. As I came in he gave quite a +jump in his chair and turned quickly to Miss Stoper. + +"'That will do,' said he; 'I could not ask for anything better. +Capital! capital!' He seemed quite enthusiastic and rubbed his +hands together in the most genial fashion. He was such a +comfortable-looking man that it was quite a pleasure to look at +him. + +"'You are looking for a situation, miss?' he asked. + +"'Yes, sir.' + +"'As governess?' + +"'Yes, sir.' + +"'And what salary do you ask?' + +"'I had 4 pounds a month in my last place with Colonel Spence +Munro.' + +"'Oh, tut, tut! sweating--rank sweating!' he cried, throwing his +fat hands out into the air like a man who is in a boiling +passion. 'How could anyone offer so pitiful a sum to a lady with +such attractions and accomplishments?' + +"'My accomplishments, sir, may be less than you imagine,' said I. +'A little French, a little German, music, and drawing--' + +"'Tut, tut!' he cried. 'This is all quite beside the question. +The point is, have you or have you not the bearing and deportment +of a lady? There it is in a nutshell. If you have not, you are +not fitted for the rearing of a child who may some day play a +considerable part in the history of the country. But if you have +why, then, how could any gentleman ask you to condescend to +accept anything under the three figures? Your salary with me, +madam, would commence at 100 pounds a year.' + +"You may imagine, Mr. Holmes, that to me, destitute as I was, +such an offer seemed almost too good to be true. The gentleman, +however, seeing perhaps the look of incredulity upon my face, +opened a pocket-book and took out a note. + +"'It is also my custom,' said he, smiling in the most pleasant +fashion until his eyes were just two little shining slits amid +the white creases of his face, 'to advance to my young ladies +half their salary beforehand, so that they may meet any little +expenses of their journey and their wardrobe.' + +"It seemed to me that I had never met so fascinating and so +thoughtful a man. As I was already in debt to my tradesmen, the +advance was a great convenience, and yet there was something +unnatural about the whole transaction which made me wish to know +a little more before I quite committed myself. + +"'May I ask where you live, sir?' said I. + +"'Hampshire. Charming rural place. The Copper Beeches, five miles +on the far side of Winchester. It is the most lovely country, my +dear young lady, and the dearest old country-house.' + +"'And my duties, sir? I should be glad to know what they would +be.' + +"'One child--one dear little romper just six years old. Oh, if +you could see him killing cockroaches with a slipper! Smack! +smack! smack! Three gone before you could wink!' He leaned back +in his chair and laughed his eyes into his head again. + +"I was a little startled at the nature of the child's amusement, +but the father's laughter made me think that perhaps he was +joking. + +"'My sole duties, then,' I asked, 'are to take charge of a single +child?' + +"'No, no, not the sole, not the sole, my dear young lady,' he +cried. 'Your duty would be, as I am sure your good sense would +suggest, to obey any little commands my wife might give, provided +always that they were such commands as a lady might with +propriety obey. You see no difficulty, heh?' + +"'I should be happy to make myself useful.' + +"'Quite so. In dress now, for example. We are faddy people, you +know--faddy but kind-hearted. If you were asked to wear any dress +which we might give you, you would not object to our little whim. +Heh?' + +"'No,' said I, considerably astonished at his words. + +"'Or to sit here, or sit there, that would not be offensive to +you?' + +"'Oh, no.' + +"'Or to cut your hair quite short before you come to us?' + +"I could hardly believe my ears. As you may observe, Mr. Holmes, +my hair is somewhat luxuriant, and of a rather peculiar tint of +chestnut. It has been considered artistic. I could not dream of +sacrificing it in this offhand fashion. + +"'I am afraid that that is quite impossible,' said I. He had been +watching me eagerly out of his small eyes, and I could see a +shadow pass over his face as I spoke. + +"'I am afraid that it is quite essential,' said he. 'It is a +little fancy of my wife's, and ladies' fancies, you know, madam, +ladies' fancies must be consulted. And so you won't cut your +hair?' + +"'No, sir, I really could not,' I answered firmly. + +"'Ah, very well; then that quite settles the matter. It is a +pity, because in other respects you would really have done very +nicely. In that case, Miss Stoper, I had best inspect a few more +of your young ladies.' + +"The manageress had sat all this while busy with her papers +without a word to either of us, but she glanced at me now with so +much annoyance upon her face that I could not help suspecting +that she had lost a handsome commission through my refusal. + +"'Do you desire your name to be kept upon the books?' she asked. + +"'If you please, Miss Stoper.' + +"'Well, really, it seems rather useless, since you refuse the +most excellent offers in this fashion,' said she sharply. 'You +can hardly expect us to exert ourselves to find another such +opening for you. Good-day to you, Miss Hunter.' She struck a gong +upon the table, and I was shown out by the page. + +"Well, Mr. Holmes, when I got back to my lodgings and found +little enough in the cupboard, and two or three bills upon the +table, I began to ask myself whether I had not done a very +foolish thing. After all, if these people had strange fads and +expected obedience on the most extraordinary matters, they were +at least ready to pay for their eccentricity. Very few +governesses in England are getting 100 pounds a year. Besides, +what use was my hair to me? Many people are improved by wearing +it short and perhaps I should be among the number. Next day I was +inclined to think that I had made a mistake, and by the day after +I was sure of it. I had almost overcome my pride so far as to go +back to the agency and inquire whether the place was still open +when I received this letter from the gentleman himself. I have it +here and I will read it to you: + + "'The Copper Beeches, near Winchester. +"'DEAR MISS HUNTER:--Miss Stoper has very kindly given me your +address, and I write from here to ask you whether you have +reconsidered your decision. My wife is very anxious that you +should come, for she has been much attracted by my description of +you. We are willing to give 30 pounds a quarter, or 120 pounds a +year, so as to recompense you for any little inconvenience which +our fads may cause you. They are not very exacting, after all. My +wife is fond of a particular shade of electric blue and would +like you to wear such a dress indoors in the morning. You need +not, however, go to the expense of purchasing one, as we have one +belonging to my dear daughter Alice (now in Philadelphia), which +would, I should think, fit you very well. Then, as to sitting +here or there, or amusing yourself in any manner indicated, that +need cause you no inconvenience. As regards your hair, it is no +doubt a pity, especially as I could not help remarking its beauty +during our short interview, but I am afraid that I must remain +firm upon this point, and I only hope that the increased salary +may recompense you for the loss. Your duties, as far as the child +is concerned, are very light. Now do try to come, and I shall +meet you with the dog-cart at Winchester. Let me know your train. +Yours faithfully, JEPHRO RUCASTLE.' + +"That is the letter which I have just received, Mr. Holmes, and +my mind is made up that I will accept it. I thought, however, +that before taking the final step I should like to submit the +whole matter to your consideration." + +"Well, Miss Hunter, if your mind is made up, that settles the +question," said Holmes, smiling. + +"But you would not advise me to refuse?" + +"I confess that it is not the situation which I should like to +see a sister of mine apply for." + +"What is the meaning of it all, Mr. Holmes?" + +"Ah, I have no data. I cannot tell. Perhaps you have yourself +formed some opinion?" + +"Well, there seems to me to be only one possible solution. Mr. +Rucastle seemed to be a very kind, good-natured man. Is it not +possible that his wife is a lunatic, that he desires to keep the +matter quiet for fear she should be taken to an asylum, and that +he humours her fancies in every way in order to prevent an +outbreak?" + +"That is a possible solution--in fact, as matters stand, it is +the most probable one. But in any case it does not seem to be a +nice household for a young lady." + +"But the money, Mr. Holmes, the money!" + +"Well, yes, of course the pay is good--too good. That is what +makes me uneasy. Why should they give you 120 pounds a year, when +they could have their pick for 40 pounds? There must be some +strong reason behind." + +"I thought that if I told you the circumstances you would +understand afterwards if I wanted your help. I should feel so +much stronger if I felt that you were at the back of me." + +"Oh, you may carry that feeling away with you. I assure you that +your little problem promises to be the most interesting which has +come my way for some months. There is something distinctly novel +about some of the features. If you should find yourself in doubt +or in danger--" + +"Danger! What danger do you foresee?" + +Holmes shook his head gravely. "It would cease to be a danger if +we could define it," said he. "But at any time, day or night, a +telegram would bring me down to your help." + +"That is enough." She rose briskly from her chair with the +anxiety all swept from her face. "I shall go down to Hampshire +quite easy in my mind now. I shall write to Mr. Rucastle at once, +sacrifice my poor hair to-night, and start for Winchester +to-morrow." With a few grateful words to Holmes she bade us both +good-night and bustled off upon her way. + +"At least," said I as we heard her quick, firm steps descending +the stairs, "she seems to be a young lady who is very well able +to take care of herself." + +"And she would need to be," said Holmes gravely. "I am much +mistaken if we do not hear from her before many days are past." + +It was not very long before my friend's prediction was fulfilled. +A fortnight went by, during which I frequently found my thoughts +turning in her direction and wondering what strange side-alley of +human experience this lonely woman had strayed into. The unusual +salary, the curious conditions, the light duties, all pointed to +something abnormal, though whether a fad or a plot, or whether +the man were a philanthropist or a villain, it was quite beyond +my powers to determine. As to Holmes, I observed that he sat +frequently for half an hour on end, with knitted brows and an +abstracted air, but he swept the matter away with a wave of his +hand when I mentioned it. "Data! data! data!" he cried +impatiently. "I can't make bricks without clay." And yet he would +always wind up by muttering that no sister of his should ever +have accepted such a situation. + +The telegram which we eventually received came late one night +just as I was thinking of turning in and Holmes was settling down +to one of those all-night chemical researches which he frequently +indulged in, when I would leave him stooping over a retort and a +test-tube at night and find him in the same position when I came +down to breakfast in the morning. He opened the yellow envelope, +and then, glancing at the message, threw it across to me. + +"Just look up the trains in Bradshaw," said he, and turned back +to his chemical studies. + +The summons was a brief and urgent one. + +"Please be at the Black Swan Hotel at Winchester at midday +to-morrow," it said. "Do come! I am at my wit's end. HUNTER." + +"Will you come with me?" asked Holmes, glancing up. + +"I should wish to." + +"Just look it up, then." + +"There is a train at half-past nine," said I, glancing over my +Bradshaw. "It is due at Winchester at 11:30." + +"That will do very nicely. Then perhaps I had better postpone my +analysis of the acetones, as we may need to be at our best in the +morning." + +By eleven o'clock the next day we were well upon our way to the +old English capital. Holmes had been buried in the morning papers +all the way down, but after we had passed the Hampshire border he +threw them down and began to admire the scenery. It was an ideal +spring day, a light blue sky, flecked with little fleecy white +clouds drifting across from west to east. The sun was shining +very brightly, and yet there was an exhilarating nip in the air, +which set an edge to a man's energy. All over the countryside, +away to the rolling hills around Aldershot, the little red and +grey roofs of the farm-steadings peeped out from amid the light +green of the new foliage. + +"Are they not fresh and beautiful?" I cried with all the +enthusiasm of a man fresh from the fogs of Baker Street. + +But Holmes shook his head gravely. + +"Do you know, Watson," said he, "that it is one of the curses of +a mind with a turn like mine that I must look at everything with +reference to my own special subject. You look at these scattered +houses, and you are impressed by their beauty. I look at them, +and the only thought which comes to me is a feeling of their +isolation and of the impunity with which crime may be committed +there." + +"Good heavens!" I cried. "Who would associate crime with these +dear old homesteads?" + +"They always fill me with a certain horror. It is my belief, +Watson, founded upon my experience, that the lowest and vilest +alleys in London do not present a more dreadful record of sin +than does the smiling and beautiful countryside." + +"You horrify me!" + +"But the reason is very obvious. The pressure of public opinion +can do in the town what the law cannot accomplish. There is no +lane so vile that the scream of a tortured child, or the thud of +a drunkard's blow, does not beget sympathy and indignation among +the neighbours, and then the whole machinery of justice is ever +so close that a word of complaint can set it going, and there is +but a step between the crime and the dock. But look at these +lonely houses, each in its own fields, filled for the most part +with poor ignorant folk who know little of the law. Think of the +deeds of hellish cruelty, the hidden wickedness which may go on, +year in, year out, in such places, and none the wiser. Had this +lady who appeals to us for help gone to live in Winchester, I +should never have had a fear for her. It is the five miles of +country which makes the danger. Still, it is clear that she is +not personally threatened." + +"No. If she can come to Winchester to meet us she can get away." + +"Quite so. She has her freedom." + +"What CAN be the matter, then? Can you suggest no explanation?" + +"I have devised seven separate explanations, each of which would +cover the facts as far as we know them. But which of these is +correct can only be determined by the fresh information which we +shall no doubt find waiting for us. Well, there is the tower of +the cathedral, and we shall soon learn all that Miss Hunter has +to tell." + +The Black Swan is an inn of repute in the High Street, at no +distance from the station, and there we found the young lady +waiting for us. She had engaged a sitting-room, and our lunch +awaited us upon the table. + +"I am so delighted that you have come," she said earnestly. "It +is so very kind of you both; but indeed I do not know what I +should do. Your advice will be altogether invaluable to me." + +"Pray tell us what has happened to you." + +"I will do so, and I must be quick, for I have promised Mr. +Rucastle to be back before three. I got his leave to come into +town this morning, though he little knew for what purpose." + +"Let us have everything in its due order." Holmes thrust his long +thin legs out towards the fire and composed himself to listen. + +"In the first place, I may say that I have met, on the whole, +with no actual ill-treatment from Mr. and Mrs. Rucastle. It is +only fair to them to say that. But I cannot understand them, and +I am not easy in my mind about them." + +"What can you not understand?" + +"Their reasons for their conduct. But you shall have it all just +as it occurred. When I came down, Mr. Rucastle met me here and +drove me in his dog-cart to the Copper Beeches. It is, as he +said, beautifully situated, but it is not beautiful in itself, +for it is a large square block of a house, whitewashed, but all +stained and streaked with damp and bad weather. There are grounds +round it, woods on three sides, and on the fourth a field which +slopes down to the Southampton highroad, which curves past about +a hundred yards from the front door. This ground in front belongs +to the house, but the woods all round are part of Lord +Southerton's preserves. A clump of copper beeches immediately in +front of the hall door has given its name to the place. + +"I was driven over by my employer, who was as amiable as ever, +and was introduced by him that evening to his wife and the child. +There was no truth, Mr. Holmes, in the conjecture which seemed to +us to be probable in your rooms at Baker Street. Mrs. Rucastle is +not mad. I found her to be a silent, pale-faced woman, much +younger than her husband, not more than thirty, I should think, +while he can hardly be less than forty-five. From their +conversation I have gathered that they have been married about +seven years, that he was a widower, and that his only child by +the first wife was the daughter who has gone to Philadelphia. Mr. +Rucastle told me in private that the reason why she had left them +was that she had an unreasoning aversion to her stepmother. As +the daughter could not have been less than twenty, I can quite +imagine that her position must have been uncomfortable with her +father's young wife. + +"Mrs. Rucastle seemed to me to be colourless in mind as well as +in feature. She impressed me neither favourably nor the reverse. +She was a nonentity. It was easy to see that she was passionately +devoted both to her husband and to her little son. Her light grey +eyes wandered continually from one to the other, noting every +little want and forestalling it if possible. He was kind to her +also in his bluff, boisterous fashion, and on the whole they +seemed to be a happy couple. And yet she had some secret sorrow, +this woman. She would often be lost in deep thought, with the +saddest look upon her face. More than once I have surprised her +in tears. I have thought sometimes that it was the disposition of +her child which weighed upon her mind, for I have never met so +utterly spoiled and so ill-natured a little creature. He is small +for his age, with a head which is quite disproportionately large. +His whole life appears to be spent in an alternation between +savage fits of passion and gloomy intervals of sulking. Giving +pain to any creature weaker than himself seems to be his one idea +of amusement, and he shows quite remarkable talent in planning +the capture of mice, little birds, and insects. But I would +rather not talk about the creature, Mr. Holmes, and, indeed, he +has little to do with my story." + +"I am glad of all details," remarked my friend, "whether they +seem to you to be relevant or not." + +"I shall try not to miss anything of importance. The one +unpleasant thing about the house, which struck me at once, was +the appearance and conduct of the servants. There are only two, a +man and his wife. Toller, for that is his name, is a rough, +uncouth man, with grizzled hair and whiskers, and a perpetual +smell of drink. Twice since I have been with them he has been +quite drunk, and yet Mr. Rucastle seemed to take no notice of it. +His wife is a very tall and strong woman with a sour face, as +silent as Mrs. Rucastle and much less amiable. They are a most +unpleasant couple, but fortunately I spend most of my time in the +nursery and my own room, which are next to each other in one +corner of the building. + +"For two days after my arrival at the Copper Beeches my life was +very quiet; on the third, Mrs. Rucastle came down just after +breakfast and whispered something to her husband. + +"'Oh, yes,' said he, turning to me, 'we are very much obliged to +you, Miss Hunter, for falling in with our whims so far as to cut +your hair. I assure you that it has not detracted in the tiniest +iota from your appearance. We shall now see how the electric-blue +dress will become you. You will find it laid out upon the bed in +your room, and if you would be so good as to put it on we should +both be extremely obliged.' + +"The dress which I found waiting for me was of a peculiar shade +of blue. It was of excellent material, a sort of beige, but it +bore unmistakable signs of having been worn before. It could not +have been a better fit if I had been measured for it. Both Mr. +and Mrs. Rucastle expressed a delight at the look of it, which +seemed quite exaggerated in its vehemence. They were waiting for +me in the drawing-room, which is a very large room, stretching +along the entire front of the house, with three long windows +reaching down to the floor. A chair had been placed close to the +central window, with its back turned towards it. In this I was +asked to sit, and then Mr. Rucastle, walking up and down on the +other side of the room, began to tell me a series of the funniest +stories that I have ever listened to. You cannot imagine how +comical he was, and I laughed until I was quite weary. Mrs. +Rucastle, however, who has evidently no sense of humour, never so +much as smiled, but sat with her hands in her lap, and a sad, +anxious look upon her face. After an hour or so, Mr. Rucastle +suddenly remarked that it was time to commence the duties of the +day, and that I might change my dress and go to little Edward in +the nursery. + +"Two days later this same performance was gone through under +exactly similar circumstances. Again I changed my dress, again I +sat in the window, and again I laughed very heartily at the funny +stories of which my employer had an immense répertoire, and which +he told inimitably. Then he handed me a yellow-backed novel, and +moving my chair a little sideways, that my own shadow might not +fall upon the page, he begged me to read aloud to him. I read for +about ten minutes, beginning in the heart of a chapter, and then +suddenly, in the middle of a sentence, he ordered me to cease and +to change my dress. + +"You can easily imagine, Mr. Holmes, how curious I became as to +what the meaning of this extraordinary performance could possibly +be. They were always very careful, I observed, to turn my face +away from the window, so that I became consumed with the desire +to see what was going on behind my back. At first it seemed to be +impossible, but I soon devised a means. My hand-mirror had been +broken, so a happy thought seized me, and I concealed a piece of +the glass in my handkerchief. On the next occasion, in the midst +of my laughter, I put my handkerchief up to my eyes, and was able +with a little management to see all that there was behind me. I +confess that I was disappointed. There was nothing. At least that +was my first impression. At the second glance, however, I +perceived that there was a man standing in the Southampton Road, +a small bearded man in a grey suit, who seemed to be looking in +my direction. The road is an important highway, and there are +usually people there. This man, however, was leaning against the +railings which bordered our field and was looking earnestly up. I +lowered my handkerchief and glanced at Mrs. Rucastle to find her +eyes fixed upon me with a most searching gaze. She said nothing, +but I am convinced that she had divined that I had a mirror in my +hand and had seen what was behind me. She rose at once. + +"'Jephro,' said she, 'there is an impertinent fellow upon the +road there who stares up at Miss Hunter.' + +"'No friend of yours, Miss Hunter?' he asked. + +"'No, I know no one in these parts.' + +"'Dear me! How very impertinent! Kindly turn round and motion to +him to go away.' + +"'Surely it would be better to take no notice.' + +"'No, no, we should have him loitering here always. Kindly turn +round and wave him away like that.' + +"I did as I was told, and at the same instant Mrs. Rucastle drew +down the blind. That was a week ago, and from that time I have +not sat again in the window, nor have I worn the blue dress, nor +seen the man in the road." + +"Pray continue," said Holmes. "Your narrative promises to be a +most interesting one." + +"You will find it rather disconnected, I fear, and there may +prove to be little relation between the different incidents of +which I speak. On the very first day that I was at the Copper +Beeches, Mr. Rucastle took me to a small outhouse which stands +near the kitchen door. As we approached it I heard the sharp +rattling of a chain, and the sound as of a large animal moving +about. + +"'Look in here!' said Mr. Rucastle, showing me a slit between two +planks. 'Is he not a beauty?' + +"I looked through and was conscious of two glowing eyes, and of a +vague figure huddled up in the darkness. + +"'Don't be frightened,' said my employer, laughing at the start +which I had given. 'It's only Carlo, my mastiff. I call him mine, +but really old Toller, my groom, is the only man who can do +anything with him. We feed him once a day, and not too much then, +so that he is always as keen as mustard. Toller lets him loose +every night, and God help the trespasser whom he lays his fangs +upon. For goodness' sake don't you ever on any pretext set your +foot over the threshold at night, for it's as much as your life +is worth.' + +"The warning was no idle one, for two nights later I happened to +look out of my bedroom window about two o'clock in the morning. +It was a beautiful moonlight night, and the lawn in front of the +house was silvered over and almost as bright as day. I was +standing, rapt in the peaceful beauty of the scene, when I was +aware that something was moving under the shadow of the copper +beeches. As it emerged into the moonshine I saw what it was. It +was a giant dog, as large as a calf, tawny tinted, with hanging +jowl, black muzzle, and huge projecting bones. It walked slowly +across the lawn and vanished into the shadow upon the other side. +That dreadful sentinel sent a chill to my heart which I do not +think that any burglar could have done. + +"And now I have a very strange experience to tell you. I had, as +you know, cut off my hair in London, and I had placed it in a +great coil at the bottom of my trunk. One evening, after the +child was in bed, I began to amuse myself by examining the +furniture of my room and by rearranging my own little things. +There was an old chest of drawers in the room, the two upper ones +empty and open, the lower one locked. I had filled the first two +with my linen, and as I had still much to pack away I was +naturally annoyed at not having the use of the third drawer. It +struck me that it might have been fastened by a mere oversight, +so I took out my bunch of keys and tried to open it. The very +first key fitted to perfection, and I drew the drawer open. There +was only one thing in it, but I am sure that you would never +guess what it was. It was my coil of hair. + +"I took it up and examined it. It was of the same peculiar tint, +and the same thickness. But then the impossibility of the thing +obtruded itself upon me. How could my hair have been locked in +the drawer? With trembling hands I undid my trunk, turned out the +contents, and drew from the bottom my own hair. I laid the two +tresses together, and I assure you that they were identical. Was +it not extraordinary? Puzzle as I would, I could make nothing at +all of what it meant. I returned the strange hair to the drawer, +and I said nothing of the matter to the Rucastles as I felt that +I had put myself in the wrong by opening a drawer which they had +locked. + +"I am naturally observant, as you may have remarked, Mr. Holmes, +and I soon had a pretty good plan of the whole house in my head. +There was one wing, however, which appeared not to be inhabited +at all. A door which faced that which led into the quarters of +the Tollers opened into this suite, but it was invariably locked. +One day, however, as I ascended the stair, I met Mr. Rucastle +coming out through this door, his keys in his hand, and a look on +his face which made him a very different person to the round, +jovial man to whom I was accustomed. His cheeks were red, his +brow was all crinkled with anger, and the veins stood out at his +temples with passion. He locked the door and hurried past me +without a word or a look. + +"This aroused my curiosity, so when I went out for a walk in the +grounds with my charge, I strolled round to the side from which I +could see the windows of this part of the house. There were four +of them in a row, three of which were simply dirty, while the +fourth was shuttered up. They were evidently all deserted. As I +strolled up and down, glancing at them occasionally, Mr. Rucastle +came out to me, looking as merry and jovial as ever. + +"'Ah!' said he, 'you must not think me rude if I passed you +without a word, my dear young lady. I was preoccupied with +business matters.' + +"I assured him that I was not offended. 'By the way,' said I, +'you seem to have quite a suite of spare rooms up there, and one +of them has the shutters up.' + +"He looked surprised and, as it seemed to me, a little startled +at my remark. + +"'Photography is one of my hobbies,' said he. 'I have made my +dark room up there. But, dear me! what an observant young lady we +have come upon. Who would have believed it? Who would have ever +believed it?' He spoke in a jesting tone, but there was no jest +in his eyes as he looked at me. I read suspicion there and +annoyance, but no jest. + +"Well, Mr. Holmes, from the moment that I understood that there +was something about that suite of rooms which I was not to know, +I was all on fire to go over them. It was not mere curiosity, +though I have my share of that. It was more a feeling of duty--a +feeling that some good might come from my penetrating to this +place. They talk of woman's instinct; perhaps it was woman's +instinct which gave me that feeling. At any rate, it was there, +and I was keenly on the lookout for any chance to pass the +forbidden door. + +"It was only yesterday that the chance came. I may tell you that, +besides Mr. Rucastle, both Toller and his wife find something to +do in these deserted rooms, and I once saw him carrying a large +black linen bag with him through the door. Recently he has been +drinking hard, and yesterday evening he was very drunk; and when +I came upstairs there was the key in the door. I have no doubt at +all that he had left it there. Mr. and Mrs. Rucastle were both +downstairs, and the child was with them, so that I had an +admirable opportunity. I turned the key gently in the lock, +opened the door, and slipped through. + +"There was a little passage in front of me, unpapered and +uncarpeted, which turned at a right angle at the farther end. +Round this corner were three doors in a line, the first and third +of which were open. They each led into an empty room, dusty and +cheerless, with two windows in the one and one in the other, so +thick with dirt that the evening light glimmered dimly through +them. The centre door was closed, and across the outside of it +had been fastened one of the broad bars of an iron bed, padlocked +at one end to a ring in the wall, and fastened at the other with +stout cord. The door itself was locked as well, and the key was +not there. This barricaded door corresponded clearly with the +shuttered window outside, and yet I could see by the glimmer from +beneath it that the room was not in darkness. Evidently there was +a skylight which let in light from above. As I stood in the +passage gazing at the sinister door and wondering what secret it +might veil, I suddenly heard the sound of steps within the room +and saw a shadow pass backward and forward against the little +slit of dim light which shone out from under the door. A mad, +unreasoning terror rose up in me at the sight, Mr. Holmes. My +overstrung nerves failed me suddenly, and I turned and ran--ran +as though some dreadful hand were behind me clutching at the +skirt of my dress. I rushed down the passage, through the door, +and straight into the arms of Mr. Rucastle, who was waiting +outside. + +"'So,' said he, smiling, 'it was you, then. I thought that it +must be when I saw the door open.' + +"'Oh, I am so frightened!' I panted. + +"'My dear young lady! my dear young lady!'--you cannot think how +caressing and soothing his manner was--'and what has frightened +you, my dear young lady?' + +"But his voice was just a little too coaxing. He overdid it. I +was keenly on my guard against him. + +"'I was foolish enough to go into the empty wing,' I answered. +'But it is so lonely and eerie in this dim light that I was +frightened and ran out again. Oh, it is so dreadfully still in +there!' + +"'Only that?' said he, looking at me keenly. + +"'Why, what did you think?' I asked. + +"'Why do you think that I lock this door?' + +"'I am sure that I do not know.' + +"'It is to keep people out who have no business there. Do you +see?' He was still smiling in the most amiable manner. + +"'I am sure if I had known--' + +"'Well, then, you know now. And if you ever put your foot over +that threshold again'--here in an instant the smile hardened into +a grin of rage, and he glared down at me with the face of a +demon--'I'll throw you to the mastiff.' + +"I was so terrified that I do not know what I did. I suppose that +I must have rushed past him into my room. I remember nothing +until I found myself lying on my bed trembling all over. Then I +thought of you, Mr. Holmes. I could not live there longer without +some advice. I was frightened of the house, of the man, of the +woman, of the servants, even of the child. They were all horrible +to me. If I could only bring you down all would be well. Of +course I might have fled from the house, but my curiosity was +almost as strong as my fears. My mind was soon made up. I would +send you a wire. I put on my hat and cloak, went down to the +office, which is about half a mile from the house, and then +returned, feeling very much easier. A horrible doubt came into my +mind as I approached the door lest the dog might be loose, but I +remembered that Toller had drunk himself into a state of +insensibility that evening, and I knew that he was the only one +in the household who had any influence with the savage creature, +or who would venture to set him free. I slipped in in safety and +lay awake half the night in my joy at the thought of seeing you. +I had no difficulty in getting leave to come into Winchester this +morning, but I must be back before three o'clock, for Mr. and +Mrs. Rucastle are going on a visit, and will be away all the +evening, so that I must look after the child. Now I have told you +all my adventures, Mr. Holmes, and I should be very glad if you +could tell me what it all means, and, above all, what I should +do." + +Holmes and I had listened spellbound to this extraordinary story. +My friend rose now and paced up and down the room, his hands in +his pockets, and an expression of the most profound gravity upon +his face. + +"Is Toller still drunk?" he asked. + +"Yes. I heard his wife tell Mrs. Rucastle that she could do +nothing with him." + +"That is well. And the Rucastles go out to-night?" + +"Yes." + +"Is there a cellar with a good strong lock?" + +"Yes, the wine-cellar." + +"You seem to me to have acted all through this matter like a very +brave and sensible girl, Miss Hunter. Do you think that you could +perform one more feat? I should not ask it of you if I did not +think you a quite exceptional woman." + +"I will try. What is it?" + +"We shall be at the Copper Beeches by seven o'clock, my friend +and I. The Rucastles will be gone by that time, and Toller will, +we hope, be incapable. There only remains Mrs. Toller, who might +give the alarm. If you could send her into the cellar on some +errand, and then turn the key upon her, you would facilitate +matters immensely." + +"I will do it." + +"Excellent! We shall then look thoroughly into the affair. Of +course there is only one feasible explanation. You have been +brought there to personate someone, and the real person is +imprisoned in this chamber. That is obvious. As to who this +prisoner is, I have no doubt that it is the daughter, Miss Alice +Rucastle, if I remember right, who was said to have gone to +America. You were chosen, doubtless, as resembling her in height, +figure, and the colour of your hair. Hers had been cut off, very +possibly in some illness through which she has passed, and so, of +course, yours had to be sacrificed also. By a curious chance you +came upon her tresses. The man in the road was undoubtedly some +friend of hers--possibly her fiancé--and no doubt, as you wore +the girl's dress and were so like her, he was convinced from your +laughter, whenever he saw you, and afterwards from your gesture, +that Miss Rucastle was perfectly happy, and that she no longer +desired his attentions. The dog is let loose at night to prevent +him from endeavouring to communicate with her. So much is fairly +clear. The most serious point in the case is the disposition of +the child." + +"What on earth has that to do with it?" I ejaculated. + +"My dear Watson, you as a medical man are continually gaining +light as to the tendencies of a child by the study of the +parents. Don't you see that the converse is equally valid. I have +frequently gained my first real insight into the character of +parents by studying their children. This child's disposition is +abnormally cruel, merely for cruelty's sake, and whether he +derives this from his smiling father, as I should suspect, or +from his mother, it bodes evil for the poor girl who is in their +power." + +"I am sure that you are right, Mr. Holmes," cried our client. "A +thousand things come back to me which make me certain that you +have hit it. Oh, let us lose not an instant in bringing help to +this poor creature." + +"We must be circumspect, for we are dealing with a very cunning +man. We can do nothing until seven o'clock. At that hour we shall +be with you, and it will not be long before we solve the +mystery." + +We were as good as our word, for it was just seven when we +reached the Copper Beeches, having put up our trap at a wayside +public-house. The group of trees, with their dark leaves shining +like burnished metal in the light of the setting sun, were +sufficient to mark the house even had Miss Hunter not been +standing smiling on the door-step. + +"Have you managed it?" asked Holmes. + +A loud thudding noise came from somewhere downstairs. "That is +Mrs. Toller in the cellar," said she. "Her husband lies snoring +on the kitchen rug. Here are his keys, which are the duplicates +of Mr. Rucastle's." + +"You have done well indeed!" cried Holmes with enthusiasm. "Now +lead the way, and we shall soon see the end of this black +business." + +We passed up the stair, unlocked the door, followed on down a +passage, and found ourselves in front of the barricade which Miss +Hunter had described. Holmes cut the cord and removed the +transverse bar. Then he tried the various keys in the lock, but +without success. No sound came from within, and at the silence +Holmes' face clouded over. + +"I trust that we are not too late," said he. "I think, Miss +Hunter, that we had better go in without you. Now, Watson, put +your shoulder to it, and we shall see whether we cannot make our +way in." + +It was an old rickety door and gave at once before our united +strength. Together we rushed into the room. It was empty. There +was no furniture save a little pallet bed, a small table, and a +basketful of linen. The skylight above was open, and the prisoner +gone. + +"There has been some villainy here," said Holmes; "this beauty +has guessed Miss Hunter's intentions and has carried his victim +off." + +"But how?" + +"Through the skylight. We shall soon see how he managed it." He +swung himself up onto the roof. "Ah, yes," he cried, "here's the +end of a long light ladder against the eaves. That is how he did +it." + +"But it is impossible," said Miss Hunter; "the ladder was not +there when the Rucastles went away." + +"He has come back and done it. I tell you that he is a clever and +dangerous man. I should not be very much surprised if this were +he whose step I hear now upon the stair. I think, Watson, that it +would be as well for you to have your pistol ready." + +The words were hardly out of his mouth before a man appeared at +the door of the room, a very fat and burly man, with a heavy +stick in his hand. Miss Hunter screamed and shrunk against the +wall at the sight of him, but Sherlock Holmes sprang forward and +confronted him. + +"You villain!" said he, "where's your daughter?" + +The fat man cast his eyes round, and then up at the open +skylight. + +"It is for me to ask you that," he shrieked, "you thieves! Spies +and thieves! I have caught you, have I? You are in my power. I'll +serve you!" He turned and clattered down the stairs as hard as he +could go. + +"He's gone for the dog!" cried Miss Hunter. + +"I have my revolver," said I. + +"Better close the front door," cried Holmes, and we all rushed +down the stairs together. We had hardly reached the hall when we +heard the baying of a hound, and then a scream of agony, with a +horrible worrying sound which it was dreadful to listen to. An +elderly man with a red face and shaking limbs came staggering out +at a side door. + +"My God!" he cried. "Someone has loosed the dog. It's not been +fed for two days. Quick, quick, or it'll be too late!" + +Holmes and I rushed out and round the angle of the house, with +Toller hurrying behind us. There was the huge famished brute, its +black muzzle buried in Rucastle's throat, while he writhed and +screamed upon the ground. Running up, I blew its brains out, and +it fell over with its keen white teeth still meeting in the great +creases of his neck. With much labour we separated them and +carried him, living but horribly mangled, into the house. We laid +him upon the drawing-room sofa, and having dispatched the sobered +Toller to bear the news to his wife, I did what I could to +relieve his pain. We were all assembled round him when the door +opened, and a tall, gaunt woman entered the room. + +"Mrs. Toller!" cried Miss Hunter. + +"Yes, miss. Mr. Rucastle let me out when he came back before he +went up to you. Ah, miss, it is a pity you didn't let me know +what you were planning, for I would have told you that your pains +were wasted." + +"Ha!" said Holmes, looking keenly at her. "It is clear that Mrs. +Toller knows more about this matter than anyone else." + +"Yes, sir, I do, and I am ready enough to tell what I know." + +"Then, pray, sit down, and let us hear it for there are several +points on which I must confess that I am still in the dark." + +"I will soon make it clear to you," said she; "and I'd have done +so before now if I could ha' got out from the cellar. If there's +police-court business over this, you'll remember that I was the +one that stood your friend, and that I was Miss Alice's friend +too. + +"She was never happy at home, Miss Alice wasn't, from the time +that her father married again. She was slighted like and had no +say in anything, but it never really became bad for her until +after she met Mr. Fowler at a friend's house. As well as I could +learn, Miss Alice had rights of her own by will, but she was so +quiet and patient, she was, that she never said a word about them +but just left everything in Mr. Rucastle's hands. He knew he was +safe with her; but when there was a chance of a husband coming +forward, who would ask for all that the law would give him, then +her father thought it time to put a stop on it. He wanted her to +sign a paper, so that whether she married or not, he could use +her money. When she wouldn't do it, he kept on worrying her until +she got brain-fever, and for six weeks was at death's door. Then +she got better at last, all worn to a shadow, and with her +beautiful hair cut off; but that didn't make no change in her +young man, and he stuck to her as true as man could be." + +"Ah," said Holmes, "I think that what you have been good enough +to tell us makes the matter fairly clear, and that I can deduce +all that remains. Mr. Rucastle then, I presume, took to this +system of imprisonment?" + +"Yes, sir." + +"And brought Miss Hunter down from London in order to get rid of +the disagreeable persistence of Mr. Fowler." + +"That was it, sir." + +"But Mr. Fowler being a persevering man, as a good seaman should +be, blockaded the house, and having met you succeeded by certain +arguments, metallic or otherwise, in convincing you that your +interests were the same as his." + +"Mr. Fowler was a very kind-spoken, free-handed gentleman," said +Mrs. Toller serenely. + +"And in this way he managed that your good man should have no +want of drink, and that a ladder should be ready at the moment +when your master had gone out." + +"You have it, sir, just as it happened." + +"I am sure we owe you an apology, Mrs. Toller," said Holmes, "for +you have certainly cleared up everything which puzzled us. And +here comes the country surgeon and Mrs. Rucastle, so I think, +Watson, that we had best escort Miss Hunter back to Winchester, +as it seems to me that our locus standi now is rather a +questionable one." + +And thus was solved the mystery of the sinister house with the +copper beeches in front of the door. Mr. Rucastle survived, but +was always a broken man, kept alive solely through the care of +his devoted wife. They still live with their old servants, who +probably know so much of Rucastle's past life that he finds it +difficult to part from them. Mr. Fowler and Miss Rucastle were +married, by special license, in Southampton the day after their +flight, and he is now the holder of a government appointment in +the island of Mauritius. As to Miss Violet Hunter, my friend +Holmes, rather to my disappointment, manifested no further +interest in her when once she had ceased to be the centre of one +of his problems, and she is now the head of a private school at +Walsall, where I believe that she has met with considerable success. + + + + + + + + + +End of the Project Gutenberg EBook of The Adventures of Sherlock Holmes, by +Arthur Conan Doyle + +*** END OF THIS PROJECT GUTENBERG EBOOK THE ADVENTURES OF SHERLOCK HOLMES *** + +***** This file should be named 1661-8.txt or 1661-8.zip ***** +This and all associated files of various formats will be found in: + http://www.gutenberg.org/1/6/6/1661/ + +Produced by an anonymous Project Gutenberg volunteer and Jose Menendez + +Updated editions will replace the previous one--the old editions +will be renamed. + +Creating the works from public domain print editions means that no +one owns a United States copyright in these works, so the Foundation +(and you!) can copy and distribute it in the United States without +permission and without paying copyright royalties. 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regex!("(a|b)*a(a|b){20}"); + println!("searching..."); + for m in re.find_iter(&input) { + println!("{:?}", m); + } + + // let input = " Wed Nov 4 16:26:23 EST 2015"; + // let re = regex!(DATETIME); + // for m in re.find_iter(&input) { + // println!("{:?}", m); + // } +} + +fn make_input(size: usize) -> String { + let mut rng = thread_rng(); + let mut s = String::with_capacity(size); + for _ in 0..size { + s.push(if rng.gen() { 'a' } else { 'b'}); + } + s +} + +static DATETIME: &'static str = "\ +(?i)(?:(?:(?:(?:(?:monday|tuesday|wednesday|thursday|friday|saturday|sunday)|(?:mon|tue[s]?|wed|thu[r]?|fri|sat|sun))(?:(?:[,])(?:(?:[ ]{1,4})?)|(?:[ ]{1,4})))?(?:(?:january|february|march|april|may|june|july|august|september|october|november|december)|(?:jan|feb|mar|apr|may|jun|jul|aug|sep[t]?|oct|nov|dec))(?:[ ]{1,4})(?:(?:[0-2]?[0-9]|3[0-1])|(?:[2-3]?1st|2?2nd|2?3rd|(?:[4-9]|1[0-9]|2[04-9]|30)th))(?:[ ]{1,4})(?:(?:(?:(?:0?[0-9]|1[0-2]):[0-5][0-9](?::[0-5][0-9])?(?:(?:[ ]{1,4})?)[AP][M])(?:(?:[ ]{1,4})(?:acdt|acst|aedt|aest|akdt|akst|amst|awdt|awst|biot|brst|cedt|cest|chot|chut|cist|clst|cost|cwst|davt|ddut|east|eedt|eest|egst|fkst|galt|gamt|gilt|hadt|haec|hast|hovt|ibst|irdt|irkt|irst|kost|krat|lhst|lint|magt|mart|mawt|mest|mist|nzdt|nzst|omst|orat|pett|phot|pmdt|pmst|pont|pyst|rott|sakt|samt|sast|slst|sret|syot|taht|ulat|uyst|vlat|volt|vost|wakt|wast|wedt|west|yakt|yekt|act|adt|aft|amt|art|ast|azt|bdt|bit|bot|brt|bst|btt|cat|cct|cdt|cet|cit|ckt|clt|cot|cst|cvt|cxt|dft|eat|ect|edt|eet|egt|eit|est|fet|fjt|fkt|fnt|get|gft|git|gmt|gst|gyt|hkt|hmt|hst|ict|idt|iot|ist|jst|kgt|kst|mdt|met|mht|mit|mmt|msk|mst|mut|mvt|myt|nct|ndt|nft|npt|nst|nut|pdt|pet|pgt|pkt|pst|pyt|ret|sbt|sct|sgt|srt|sst|tft|tha|tjt|tkt|tlt|tmt|tot|tvt|uct|utc|uyt|uzt|vet|vut|wat|wet|wit|wst))?)|(?:(?:(?:[0-1]?[0-9]|2[0-3]):[0-5][0-9](?::[0-5][0-9](?:[.][0-9][0-9])?)?)(?:(?:(?:(?:[ ]{1,4})?)(?:(?:acdt|acst|aedt|aest|akdt|akst|amst|awdt|awst|biot|brst|cedt|cest|chot|chut|cist|clst|cost|cwst|davt|ddut|east|eedt|eest|egst|fkst|galt|gamt|gilt|hadt|haec|hast|hovt|ibst|irdt|irkt|irst|kost|krat|lhst|lint|magt|mart|mawt|mest|mist|nzdt|nzst|omst|orat|pett|phot|pmdt|pmst|pont|pyst|rott|sakt|samt|sast|slst|sret|syot|taht|ulat|uyst|vlat|volt|vost|wakt|wast|wedt|west|yakt|yekt|act|adt|aft|amt|art|ast|azt|bdt|bit|bot|brt|bst|btt|cat|cct|cdt|cet|cit|ckt|clt|cot|cst|cvt|cxt|dft|eat|ect|edt|eet|egt|eit|est|fet|fjt|fkt|fnt|get|gft|git|gmt|gst|gyt|hkt|hmt|hst|ict|idt|iot|ist|jst|kgt|kst|mdt|met|mht|mit|mmt|msk|mst|mut|mvt|myt|nct|ndt|nft|npt|nst|nut|pdt|pet|pgt|pkt|pst|pyt|ret|sbt|sct|sgt|srt|sst|tft|tha|tjt|tkt|tlt|tmt|tot|tvt|uct|utc|uyt|uzt|vet|vut|wat|wet|wit|wst)|(?:[-+](?:0[0-9]|1[0-2])(?:(?:[:])?)(?:00|15|30|45))))|z)?))(?:[ ]{1,4})(?:[1-2][0-9][0-9][0-9]))|(?:(?:(?:(?:(?:monday|tuesday|wednesday|thursday|friday|saturday|sunday)|(?:mon|tue[s]?|wed|thu[r]?|fri|sat|sun))(?:(?:[,])(?:(?:[ ]{1,4})?)|(?:[ ]{1,4})))?(?:(?:(?:(?:0?[1-9])|(?:1[0-2]))[-/](?:[0-2]?[0-9]|3[0-1])[-/](?:(?:[1-2][0-9][0-9][0-9])|(?:[0-9][0-9])))|(?:(?:[0-2]?[0-9]|3[0-1])[-/](?:(?:0?[1-9])|(?:1[0-2]))[-/](?:(?:[1-2][0-9][0-9][0-9])|(?:[0-9][0-9])))|(?:(?:(?:[1-2][0-9][0-9][0-9])|(?:[0-9][0-9]))[-/](?:(?:0?[1-9])|(?:1[0-2]))[-/](?:(?:[0-2]?[0-9]|3[0-1])|(?:[2-3]?1st|2?2nd|2?3rd|(?:[4-9]|1[0-9]|2[04-9]|30)th)))|(?:(?:(?:january|february|march|april|may|june|july|august|september|october|november|december)|(?:jan|feb|mar|apr|may|jun|jul|aug|sep[t]?|oct|nov|dec))(?:[ ]{1,4})(?:(?:[0-2]?[0-9]|3[0-1])|(?:[2-3]?1st|2?2nd|2?3rd|(?:[4-9]|1[0-9]|2[04-9]|30)th))(?:(?:[,])(?:(?:[ ]{1,4})?)|(?:[ ]{1,4}))(?:(?:[1-2][0-9][0-9][0-9])|(?:[0-9][0-9])))|(?:(?:(?:[0-2]?[0-9]|3[0-1])|(?:[2-3]?1st|2?2nd|2?3rd|(?:[4-9]|1[0-9]|2[04-9]|30)th))(?:[ ]{1,4})(?:(?:january|february|march|april|may|june|july|august|september|october|november|december)|(?:jan|feb|mar|apr|may|jun|jul|aug|sep[t]?|oct|nov|dec))(?:(?:[,])?)(?:(?:[ ]{1,4})?)(?:(?:[1-2][0-9][0-9][0-9])|(?:[0-9][0-9]))))(?:(?:[ ]{1,4})|(?:(?:[ ]{1,4})?)[,@T](?:(?:[ ]{1,4})?))(?:(?:(?:(?:0?[0-9]|1[0-2]):[0-5][0-9](?::[0-5][0-9])?(?:(?:[ ]{1,4})?)[AP][M])(?:(?:[ ]{1,4})(?:acdt|acst|aedt|aest|akdt|akst|amst|awdt|awst|biot|brst|cedt|cest|chot|chut|cist|clst|cost|cwst|davt|ddut|east|eedt|eest|egst|fkst|galt|gamt|gilt|hadt|haec|hast|hovt|ibst|irdt|irkt|irst|kost|krat|lhst|lint|magt|mart|mawt|mest|mist|nzdt|nzst|omst|orat|pett|phot|pmdt|pmst|pont|pyst|rott|sakt|samt|sast|slst|sret|syot|taht|ulat|uyst|vlat|volt|vost|wakt|wast|wedt|west|yakt|yekt|act|adt|aft|amt|art|ast|azt|bdt|bit|bot|brt|bst|btt|cat|cct|cdt|cet|cit|ckt|clt|cot|cst|cvt|cxt|dft|eat|ect|edt|eet|egt|eit|est|fet|fjt|fkt|fnt|get|gft|git|gmt|gst|gyt|hkt|hmt|hst|ict|idt|iot|ist|jst|kgt|kst|mdt|met|mht|mit|mmt|msk|mst|mut|mvt|myt|nct|ndt|nft|npt|nst|nut|pdt|pet|pgt|pkt|pst|pyt|ret|sbt|sct|sgt|srt|sst|tft|tha|tjt|tkt|tlt|tmt|tot|tvt|uct|utc|uyt|uzt|vet|vut|wat|wet|wit|wst))?)|(?:(?:(?:[0-1]?[0-9]|2[0-3]):[0-5][0-9](?::[0-5][0-9](?:[.][0-9][0-9])?)?)(?:(?:(?:(?:[ 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]{1,4})(?:(?:(?:(?:0?[1-9])|(?:1[0-2]))[-/](?:[0-2]?[0-9]|3[0-1])[-/](?:(?:[1-2][0-9][0-9][0-9])|(?:[0-9][0-9])))|(?:(?:[0-2]?[0-9]|3[0-1])[-/](?:(?:0?[1-9])|(?:1[0-2]))[-/](?:(?:[1-2][0-9][0-9][0-9])|(?:[0-9][0-9])))|(?:(?:(?:[1-2][0-9][0-9][0-9])|(?:[0-9][0-9]))[-/](?:(?:0?[1-9])|(?:1[0-2]))[-/](?:(?:[0-2]?[0-9]|3[0-1])|(?:[2-3]?1st|2?2nd|2?3rd|(?:[4-9]|1[0-9]|2[04-9]|30)th)))|(?:(?:(?:january|february|march|april|may|june|july|august|september|october|november|december)|(?:jan|feb|mar|apr|may|jun|jul|aug|sep[t]?|oct|nov|dec))(?:[ ]{1,4})(?:(?:[0-2]?[0-9]|3[0-1])|(?:[2-3]?1st|2?2nd|2?3rd|(?:[4-9]|1[0-9]|2[04-9]|30)th))(?:(?:[,])(?:(?:[ ]{1,4})?)|(?:[ ]{1,4}))(?:(?:[1-2][0-9][0-9][0-9])|(?:[0-9][0-9])))|(?:(?:(?:[0-2]?[0-9]|3[0-1])|(?:[2-3]?1st|2?2nd|2?3rd|(?:[4-9]|1[0-9]|2[04-9]|30)th))(?:[ ]{1,4})(?:(?:january|february|march|april|may|june|july|august|september|october|november|december)|(?:jan|feb|mar|apr|may|jun|jul|aug|sep[t]?|oct|nov|dec))(?:(?:[,])?)(?:(?:[ ]{1,4})?)(?:(?:[1-2][0-9][0-9][0-9])|(?:[0-9][0-9]))))))|(?:(?:(?:monday|tuesday|wednesday|thursday|friday|saturday|sunday)|(?:mon|tue[s]?|wed|thu[r]?|fri|sat|sun))(?:(?:[,])(?:(?:[ ]{1,4})?)|(?:[ ]{1,4})))?(?:(?:(?:(?:0?[1-9])|(?:1[0-2]))[-/](?:[0-2]?[0-9]|3[0-1])[-/](?:(?:[1-2][0-9][0-9][0-9])|(?:[0-9][0-9])))|(?:(?:[0-2]?[0-9]|3[0-1])[-/](?:(?:0?[1-9])|(?:1[0-2]))[-/](?:(?:[1-2][0-9][0-9][0-9])|(?:[0-9][0-9])))|(?:(?:(?:[1-2][0-9][0-9][0-9])|(?:[0-9][0-9]))[-/](?:(?:0?[1-9])|(?:1[0-2]))[-/](?:(?:[0-2]?[0-9]|3[0-1])|(?:[2-3]?1st|2?2nd|2?3rd|(?:[4-9]|1[0-9]|2[04-9]|30)th)))|(?:(?:(?:january|february|march|april|may|june|july|august|september|october|november|december)|(?:jan|feb|mar|apr|may|jun|jul|aug|sep[t]?|oct|nov|dec))(?:[ ]{1,4})(?:(?:[0-2]?[0-9]|3[0-1])|(?:[2-3]?1st|2?2nd|2?3rd|(?:[4-9]|1[0-9]|2[04-9]|30)th))(?:(?:[,])(?:(?:[ ]{1,4})?)|(?:[ ]{1,4}))(?:(?:[1-2][0-9][0-9][0-9])|(?:[0-9][0-9])))|(?:(?:(?:[0-2]?[0-9]|3[0-1])|(?:[2-3]?1st|2?2nd|2?3rd|(?:[4-9]|1[0-9]|2[04-9]|30)th))(?:[ ]{1,4})(?:(?:january|february|march|april|may|june|july|august|september|october|november|december)|(?:jan|feb|mar|apr|may|jun|jul|aug|sep[t]?|oct|nov|dec))(?:(?:[,])?)(?:(?:[ ]{1,4})?)(?:(?:[1-2][0-9][0-9][0-9])|(?:[0-9][0-9]))))|(?:(?:(?:(?:january|february|march|april|may|june|july|august|september|october|november|december)|(?:jan|feb|mar|apr|may|jun|jul|aug|sep[t]?|oct|nov|dec))(?:(?:[,])(?:(?:[ ]{1,4})?)|(?:[ ]{1,4}))(?:[1-2][0-9][0-9][0-9]))|(?:(?:[1-2][0-9][0-9][0-9])[-/](?:(?:0?[1-9])|(?:1[0-2])))))"; diff --git a/examples/shootout-regex-dna-cheat.rs b/examples/shootout-regex-dna-cheat.rs index 0222fd7457..57583218ba 100644 --- a/examples/shootout-regex-dna-cheat.rs +++ b/examples/shootout-regex-dna-cheat.rs @@ -38,15 +38,12 @@ fn main() { regex!("agggta[cgt]a|t[acg]taccct"), regex!("agggtaa[cgt]|[acg]ttaccct"), ]; - let mut count_promises = vec![]; - for i in 0..3 { + let mut counts = vec![]; + for variant in variants { let seq = seq_arc.clone(); - let res = variants[i * 3..i * 3 + 3].to_vec(); - count_promises.push(thread::spawn(move || { - res.into_iter() - .map(|re| (re.to_string(), re.find_iter(&seq).count())) - .collect::>() - })); + let restr = variant.to_string(); + let future = thread::spawn(move || variant.find_iter(&seq).count()); + counts.push((restr, future)); } let substs = vec![ @@ -64,15 +61,12 @@ fn main() { ]; // combined into one regex in `replace_all` let seq = replace_all(&seq, substs); - for promise in count_promises { - for (re, count) in promise.join().unwrap() { - println!("{} {}", re, count); - } + for (variant, count) in counts { + println!("{} {}", variant, count.join().unwrap()); } println!("\n{}\n{}\n{}", ilen, clen, seq.len()); } -#[allow(deprecated)] // for connect -> join in Rust 1.3 fn replace_all(text: &str, substs: Vec<(u8, &str)>) -> String { let mut replacements = vec![""; 256]; let mut alternates = vec![]; @@ -81,7 +75,7 @@ fn replace_all(text: &str, substs: Vec<(u8, &str)>) -> String { alternates.push((re as char).to_string()); } - let re = regex!(&alternates.connect("|")); + let re = regex!(&alternates.join("|")); let mut new = String::with_capacity(text.len()); let mut last_match = 0; for (s, e) in re.find_iter(text) { diff --git a/examples/shootout-regex-dna-replace.rs b/examples/shootout-regex-dna-replace.rs new file mode 100644 index 0000000000..a3319ad29d --- /dev/null +++ b/examples/shootout-regex-dna-replace.rs @@ -0,0 +1,19 @@ +extern crate regex; + +use std::io::{self, Read}; + +macro_rules! regex { + ($re:expr) => {{ + use regex::internal::ExecBuilder; + ExecBuilder::new($re).build().unwrap().into_regex() + }} +} + +fn main() { + let mut seq = String::with_capacity(50 * (1 << 20)); + io::stdin().read_to_string(&mut seq).unwrap(); + let ilen = seq.len(); + + seq = regex!(">[^\n]*\n|\n").replace_all(&seq, ""); + println!("original: {}, replaced: {}", ilen, seq.len()); +} diff --git a/examples/shootout-regex-dna-single-cheat.rs b/examples/shootout-regex-dna-single-cheat.rs new file mode 100644 index 0000000000..fbf464202f --- /dev/null +++ b/examples/shootout-regex-dna-single-cheat.rs @@ -0,0 +1,73 @@ +// The Computer Language Benchmarks Game +// http://benchmarksgame.alioth.debian.org/ +// +// contributed by the Rust Project Developers +// contributed by TeXitoi +// contributed by BurntSushi + +extern crate regex; + +use std::io::{self, Read}; + +macro_rules! regex { ($re:expr) => { ::regex::Regex::new($re).unwrap() } } + +fn main() { + let mut seq = String::with_capacity(50 * (1 << 20)); + io::stdin().read_to_string(&mut seq).unwrap(); + let ilen = seq.len(); + + seq = regex!(">[^\n]*\n|\n").replace_all(&seq, ""); + let clen = seq.len(); + + let variants = vec![ + regex!("agggtaaa|tttaccct"), + regex!("[cgt]gggtaaa|tttaccc[acg]"), + regex!("a[act]ggtaaa|tttacc[agt]t"), + regex!("ag[act]gtaaa|tttac[agt]ct"), + regex!("agg[act]taaa|ttta[agt]cct"), + regex!("aggg[acg]aaa|ttt[cgt]ccct"), + regex!("agggt[cgt]aa|tt[acg]accct"), + regex!("agggta[cgt]a|t[acg]taccct"), + regex!("agggtaa[cgt]|[acg]ttaccct"), + ]; + for re in variants { + println!("{} {}", re.to_string(), re.find_iter(&seq).count()); + } + + let substs = vec![ + (b'B', "(c|g|t)"), + (b'D', "(a|g|t)"), + (b'H', "(a|c|t)"), + (b'K', "(g|t)"), + (b'M', "(a|c)"), + (b'N', "(a|c|g|t)"), + (b'R', "(a|g)"), + (b'S', "(c|g)"), + (b'V', "(a|c|g)"), + (b'W', "(a|t)"), + (b'Y', "(c|t)"), + ]; // combined into one regex in `replace_all` + let seq = replace_all(&seq, substs); + + println!("\n{}\n{}\n{}", ilen, clen, seq.len()); +} + +fn replace_all(text: &str, substs: Vec<(u8, &str)>) -> String { + let mut replacements = vec![""; 256]; + let mut alternates = vec![]; + for (re, replacement) in substs { + replacements[re as usize] = replacement; + alternates.push((re as char).to_string()); + } + + let re = regex!(&alternates.join("|")); + let mut new = String::with_capacity(text.len()); + let mut last_match = 0; + for (s, e) in re.find_iter(text) { + new.push_str(&text[last_match..s]); + new.push_str(replacements[text.as_bytes()[s] as usize]); + last_match = e; + } + new.push_str(&text[last_match..]); + new +} diff --git a/examples/shootout-regex-dna.rs b/examples/shootout-regex-dna.rs index 5869624026..2cd0b65bb1 100644 --- a/examples/shootout-regex-dna.rs +++ b/examples/shootout-regex-dna.rs @@ -33,15 +33,12 @@ fn main() { regex!("agggta[cgt]a|t[acg]taccct"), regex!("agggtaa[cgt]|[acg]ttaccct"), ]; - let mut count_promises = vec![]; - for i in 0..3 { + let mut counts = vec![]; + for variant in variants { let seq = seq_arc.clone(); - let res = variants[i * 3..i * 3 + 3].to_vec(); - count_promises.push(thread::spawn(move || { - res.into_iter() - .map(|re| (re.to_string(), re.find_iter(&seq).count())) - .collect::>() - })); + let restr = variant.to_string(); + let future = thread::spawn(move || variant.find_iter(&seq).count()); + counts.push((restr, future)); } let substs = vec![ @@ -62,10 +59,8 @@ fn main() { seq = re.replace_all(&seq, replacement); } - for promise in count_promises { - for (re, count) in promise.join().unwrap() { - println!("{} {}", re, count); - } + for (variant, count) in counts { + println!("{} {}", variant, count.join().unwrap()); } println!("\n{}\n{}\n{}", ilen, clen, seq.len()); } diff --git a/regex-syntax/src/lib.rs b/regex-syntax/src/lib.rs index 97eb7cca69..c84f18ce8a 100644 --- a/regex-syntax/src/lib.rs +++ b/regex-syntax/src/lib.rs @@ -84,6 +84,9 @@ use self::Repeater::*; pub use parser::is_punct; +/// The maximum number of nested expressions allowed. +const NEST_LIMIT: usize = 200; + /// A regular expression abstract syntax tree. /// /// An `Expr` represents the abstract syntax of a regular expression. @@ -226,7 +229,7 @@ pub struct ClassRange { impl Expr { /// Parses a string in a regular expression syntax tree. pub fn parse(s: &str) -> Result { - parser::Parser::parse(s).map(|e| e.simplify()) + parser::Parser::parse(s).and_then(|e| e.simplify()) } /// Returns true iff the expression can be repeated by a quantifier. @@ -244,7 +247,7 @@ impl Expr { } } - fn simplify(self) -> Expr { + fn simplify(self) -> Result { fn combine_literals(es: &mut Vec, e: Expr) { match (es.pop(), e) { (None, e) => es.push(e), @@ -264,35 +267,76 @@ impl Expr { } } } - match self { - Repeat { e, r, greedy } => Repeat { - e: Box::new(e.simplify()), - r: r, - greedy: greedy, - }, - Group { e, i, name } => { - let e = e.simplify(); - if i.is_none() && name.is_none() && e.can_repeat() { - e - } else { - Group { e: Box::new(e), i: i, name: name } - } + fn simp(expr: Expr, recurse: usize) -> Result { + if recurse > NEST_LIMIT { + return Err(Error { + pos: 0, + surround: "".to_owned(), + kind: ErrorKind::StackExhausted, + }); } - Concat(es) => { - let mut new_es = Vec::with_capacity(es.len()); - for e in es { - combine_literals(&mut new_es, e.simplify()); + let simplify = |e| simp(e, recurse + 1); + Ok(match expr { + Repeat { e, r, greedy } => Repeat { + e: Box::new(try!(simplify(*e))), + r: r, + greedy: greedy, + }, + Group { e, i, name } => { + let e = try!(simplify(*e)); + if i.is_none() && name.is_none() && e.can_repeat() { + e + } else { + Group { e: Box::new(e), i: i, name: name } + } } - if new_es.len() == 1 { - new_es.pop().unwrap() - } else { - Concat(new_es) + Concat(es) => { + let mut new_es = Vec::with_capacity(es.len()); + for e in es { + combine_literals(&mut new_es, try!(simplify(e))); + } + if new_es.len() == 1 { + new_es.pop().unwrap() + } else { + Concat(new_es) + } } - } - Alternate(es) => Alternate(es.into_iter() - .map(|e| e.simplify()) - .collect()), - e => e, + Alternate(es) => { + let mut new_es = Vec::with_capacity(es.len()); + for e in es { + new_es.push(try!(simplify(e))); + } + Alternate(new_es) + } + e => e, + }) + } + simp(self, 0) + } + + /// Returns true if and only if the expression is required to match from + /// the beginning of text. + pub fn is_anchored_start(&self) -> bool { + match *self { + Repeat { ref e, .. } => e.is_anchored_start(), + Group { ref e, .. } => e.is_anchored_start(), + Concat(ref es) => es[0].is_anchored_start(), + Alternate(ref es) => es.iter().all(|e| e.is_anchored_start()), + StartText => true, + _ => false, + } + } + + /// Returns true if and only if the expression is required to match at the + /// end of the text. + pub fn is_anchored_end(&self) -> bool { + match *self { + Repeat { ref e, .. } => e.is_anchored_end(), + Group { ref e, .. } => e.is_anchored_end(), + Concat(ref es) => es[es.len() - 1].is_anchored_end(), + Alternate(ref es) => es.iter().all(|e| e.is_anchored_end()), + EndText => true, + _ => false, } } } @@ -719,6 +763,12 @@ pub enum ErrorKind { UnrecognizedFlag(char), /// Unrecognized named Unicode class. e.g., `\p{Foo}`. UnrecognizedUnicodeClass(String), + /// Indicates that the regex uses too much nesting. + /// + /// (N.B. This error exists because traversing the Expr is recursive and + /// an explicit heap allocated stack is not (yet?) used. Regardless, some + /// sort of limit must be applied to avoid unbounded memory growth. + StackExhausted, /// Hints that destructuring should not be exhaustive. /// /// This enum may grow additional variants, so this makes sure clients @@ -777,6 +827,7 @@ impl ErrorKind { UnrecognizedEscape(_) => "unrecognized escape sequence", UnrecognizedFlag(_) => "unrecognized flag", UnrecognizedUnicodeClass(_) => "unrecognized Unicode class name", + StackExhausted => "stack exhausted, too much nesting", __Nonexhaustive => unreachable!(), } } @@ -790,8 +841,13 @@ impl ::std::error::Error for Error { impl fmt::Display for Error { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - write!(f, "Error parsing regex near '{}' at character offset {}: {}", - self.surround, self.pos, self.kind) + if let ErrorKind::StackExhausted = self.kind { + write!(f, "Error parsing regex: {}", self.kind) + } else { + write!( + f, "Error parsing regex near '{}' at character offset {}: {}", + self.surround, self.pos, self.kind) + } } } @@ -871,6 +927,9 @@ impl fmt::Display for ErrorKind { (Allowed flags: i, s, m, U, x.)", c), UnrecognizedUnicodeClass(ref s) => write!(f, "Unrecognized Unicode class name: '{}'.", s), + StackExhausted => + write!(f, "Exhausted space required to parse regex with too \ + much nesting."), __Nonexhaustive => unreachable!(), } } @@ -973,7 +1032,7 @@ mod properties; #[cfg(test)] mod tests { - use {CharClass, ClassRange}; + use {NEST_LIMIT, CharClass, ClassRange, Expr}; fn class(ranges: &[(char, char)]) -> CharClass { let ranges = ranges.iter().cloned() @@ -983,6 +1042,51 @@ mod tests { fn classi(ranges: &[(char, char)]) -> CharClass { class(ranges) } + fn e(re: &str) -> Expr { Expr::parse(re).unwrap() } + + #[test] + fn stack_exhaustion() { + use std::iter::repeat; + + let open: String = repeat('(').take(NEST_LIMIT).collect(); + let close: String = repeat(')').take(NEST_LIMIT).collect(); + assert!(Expr::parse(&format!("{}a{}", open, close)).is_ok()); + + let open: String = repeat('(').take(NEST_LIMIT + 1).collect(); + let close: String = repeat(')').take(NEST_LIMIT + 1).collect(); + assert!(Expr::parse(&format!("{}a{}", open, close)).is_err()); + } + + #[test] + fn anchored_start() { + assert!(e("^a").is_anchored_start()); + assert!(e("(^a)").is_anchored_start()); + assert!(e("^a|^b").is_anchored_start()); + assert!(e("(^a)|(^b)").is_anchored_start()); + assert!(e("(^(a|b))").is_anchored_start()); + assert!(e("^*").is_anchored_start()); + assert!(e("(^)*").is_anchored_start()); + assert!(e("((^)*)*").is_anchored_start()); + + assert!(!e("^a|b").is_anchored_start()); + assert!(!e("a|^b").is_anchored_start()); + } + + #[test] + fn anchored_end() { + assert!(e("a$").is_anchored_end()); + assert!(e("(a$)").is_anchored_end()); + assert!(e("a$|b$").is_anchored_end()); + assert!(e("(a$)|(b$)").is_anchored_end()); + assert!(e("((a|b)$)").is_anchored_end()); + assert!(e("$*").is_anchored_end()); + assert!(e("($)*").is_anchored_end()); + assert!(e("(($)*)*").is_anchored_end()); + + assert!(!e("a$|b").is_anchored_end()); + assert!(!e("a|b$").is_anchored_end()); + } + #[test] fn class_canon_no_change() { let cls = class(&[('a', 'c'), ('x', 'z')]); diff --git a/regex-syntax/src/properties.rs b/regex-syntax/src/properties.rs index 284f3a4182..c84c912611 100644 --- a/regex-syntax/src/properties.rs +++ b/regex-syntax/src/properties.rs @@ -128,7 +128,8 @@ fn parser_never_panics() { impl Arbitrary for Expr { fn arbitrary(g: &mut G) -> Expr { - fix_capture_indices(gen_expr(g, 0, ExprType::Anything)).simplify() + let e = fix_capture_indices(gen_expr(g, 0, ExprType::Anything)); + e.simplify().unwrap() } fn shrink(&self) -> Box> { @@ -192,7 +193,7 @@ impl Arbitrary for Expr { })) } }; - Box::new(es.map(|e| fix_capture_indices(e).simplify())) + Box::new(es.map(|e| fix_capture_indices(e).simplify().unwrap())) } } diff --git a/regex_macros/Cargo.toml b/regex_macros/Cargo.toml index fa8ec6c1fa..2d02e53e73 100644 --- a/regex_macros/Cargo.toml +++ b/regex_macros/Cargo.toml @@ -7,26 +7,32 @@ repository = "https://github.com/rust-lang/regex" homepage = "https://github.com/rust-lang/regex" description = """ An implementation of statically compiled regular expressions for Rust. + +Unless you specifically need compile time regular expressions or a matching +engine that is guaranteed not to allocate, you should temporarily prefer using +the plain regex crate (since it is almost always faster). """ [lib] name = "regex_macros" plugin = true -[[test]] -path = "tests/test_native.rs" -name = "all" - -[[bench]] -name = "all" -path = "benches/bench_native.rs" -test = false -bench = true - [dependencies.regex] path = ".." version = "0.1" features = ["pattern"] [dev-dependencies] +lazy_static = "0.1" rand = "0.3" +regex-syntax = { path = "../regex-syntax", version = "0.2" } + +[[test]] +path = "../tests/test_native.rs" +name = "native" + +[[bench]] +name = "native" +path = "../benches/bench_native.rs" +test = false +bench = true diff --git a/regex_macros/benches/bench.rs b/regex_macros/benches/bench.rs deleted file mode 100644 index 9cb0c809a1..0000000000 --- a/regex_macros/benches/bench.rs +++ /dev/null @@ -1,196 +0,0 @@ -// Copyright 2014 The Rust Project Developers. See the COPYRIGHT -// file at the top-level directory of this distribution and at -// http://rust-lang.org/COPYRIGHT. -// -// Licensed under the Apache License, Version 2.0 or the MIT license -// , at your -// option. This file may not be copied, modified, or distributed -// except according to those terms. -#![allow(non_snake_case)] - -use std::iter::repeat; -use test::Bencher; -use rand::{Rng, thread_rng}; -use regex::{Regex, NoExpand}; - -fn bench_assert_match(b: &mut Bencher, re: Regex, text: &str) { - b.iter(|| if !re.is_match(text) { panic!("no match") }); -} - -#[bench] -fn no_exponential(b: &mut Bencher) { - let n = 100; - let regex_string = format!( - "{}{}", - repeat("a?").take(n).collect::(), - repeat("a").take(n).collect::()); - let re = Regex::new(®ex_string).unwrap(); - let text: String = repeat("a").take(n).collect(); - bench_assert_match(b, re, &text); -} - -#[bench] -fn literal(b: &mut Bencher) { - let re = regex!("y"); - let text = format!("{}y", repeat("x").take(50).collect::()); - bench_assert_match(b, re, &text); -} - -#[bench] -fn not_literal(b: &mut Bencher) { - let re = regex!(".y"); - let text = format!("{}y", repeat("x").take(50).collect::()); - bench_assert_match(b, re, &text); -} - -#[bench] -fn match_class(b: &mut Bencher) { - let re = regex!("[abcdw]"); - let text = format!("{}w", repeat("xxxx").take(20).collect::()); - bench_assert_match(b, re, &text); -} - -#[bench] -fn match_class_in_range(b: &mut Bencher) { - // 'b' is between 'a' and 'c', so the class range checking doesn't help. - let re = regex!("[ac]"); - let text = format!("{}c", repeat("bbbb").take(20).collect::()); - bench_assert_match(b, re, &text); -} - -#[bench] -fn match_class_unicode(b: &mut Bencher) { - let re = regex!(r"\pL"); - let text = format!("{}a", repeat("☃5☃5").take(20).collect::()); - bench_assert_match(b, re, &text); -} - -#[bench] -fn replace_all(b: &mut Bencher) { - let re = regex!("[cjrw]"); - let text = "abcdefghijklmnopqrstuvwxyz"; - // FIXME: This isn't using the $name expand stuff. - // It's possible RE2/Go is using it, but currently, the expand in this - // crate is actually compiling a regex, so it's incredibly slow. - b.iter(|| re.replace_all(text, NoExpand(""))); -} - -#[bench] -fn anchored_literal_short_non_match(b: &mut Bencher) { - let re = regex!("^zbc(d|e)"); - let text = "abcdefghijklmnopqrstuvwxyz"; - b.iter(|| re.is_match(text)); -} - -#[bench] -fn anchored_literal_long_non_match(b: &mut Bencher) { - let re = regex!("^zbc(d|e)"); - let text: String = repeat("abcdefghijklmnopqrstuvwxyz").take(15).collect(); - b.iter(|| re.is_match(&text)); -} - -#[bench] -fn anchored_literal_short_match(b: &mut Bencher) { - let re = regex!("^.bc(d|e)"); - let text = "abcdefghijklmnopqrstuvwxyz"; - b.iter(|| re.is_match(text)); -} - -#[bench] -fn anchored_literal_long_match(b: &mut Bencher) { - let re = regex!("^.bc(d|e)"); - let text: String = repeat("abcdefghijklmnopqrstuvwxyz").take(15).collect(); - b.iter(|| re.is_match(&text)); -} - -#[bench] -fn one_pass_short_a(b: &mut Bencher) { - let re = regex!("^.bc(d|e)*$"); - let text = "abcddddddeeeededd"; - b.iter(|| re.is_match(text)); -} - -#[bench] -fn one_pass_short_a_not(b: &mut Bencher) { - let re = regex!(".bc(d|e)*$"); - let text = "abcddddddeeeededd"; - b.iter(|| re.is_match(text)); -} - -#[bench] -fn one_pass_short_b(b: &mut Bencher) { - let re = regex!("^.bc(?:d|e)*$"); - let text = "abcddddddeeeededd"; - b.iter(|| re.is_match(text)); -} - -#[bench] -fn one_pass_short_b_not(b: &mut Bencher) { - let re = regex!(".bc(?:d|e)*$"); - let text = "abcddddddeeeededd"; - b.iter(|| re.is_match(text)); -} - -#[bench] -fn one_pass_long_prefix(b: &mut Bencher) { - let re = regex!("^abcdefghijklmnopqrstuvwxyz.*$"); - let text = "abcdefghijklmnopqrstuvwxyz"; - b.iter(|| re.is_match(text)); -} - -#[bench] -fn one_pass_long_prefix_not(b: &mut Bencher) { - let re = regex!("^.bcdefghijklmnopqrstuvwxyz.*$"); - let text = "abcdefghijklmnopqrstuvwxyz"; - b.iter(|| re.is_match(text)); -} - -macro_rules! throughput( - ($name:ident, $regex:expr, $size:expr) => ( - #[bench] - fn $name(b: &mut Bencher) { - let text = gen_text($size); - b.bytes = $size; - let re = $regex; - b.iter(|| if re.is_match(&text) { panic!("match") }); - } - ); -); - -fn easy0() -> Regex { regex!("ABCDEFGHIJKLMNOPQRSTUVWXYZ$") } -fn easy1() -> Regex { regex!("A[AB]B[BC]C[CD]D[DE]E[EF]F[FG]G[GH]H[HI]I[IJ]J$") } -fn medium() -> Regex { regex!("[XYZ]ABCDEFGHIJKLMNOPQRSTUVWXYZ$") } -fn hard() -> Regex { regex!("[ -~]*ABCDEFGHIJKLMNOPQRSTUVWXYZ$") } - -fn gen_text(n: usize) -> String { - let mut rng = thread_rng(); - let mut bytes = rng.gen_ascii_chars().map(|n| n as u8).take(n) - .collect::>(); - for (i, b) in bytes.iter_mut().enumerate() { - if i % 20 == 0 { - *b = b'\n' - } - } - String::from_utf8(bytes).unwrap() -} - -throughput!(easy0_32, easy0(), 32); -throughput!(easy0_1K, easy0(), 1<<10); -throughput!(easy0_32K, easy0(), 32<<10); -throughput!(easy0_1MB, easy0(), 1<<20); - -throughput!(easy1_32, easy1(), 32); -throughput!(easy1_1K, easy1(), 1<<10); -throughput!(easy1_32K, easy1(), 32<<10); -throughput!(easy1_1MB, easy1(), 1<<20); - -throughput!(medium_32, medium(), 32); -throughput!(medium_1K, medium(), 1<<10); -throughput!(medium_32K,medium(), 32<<10); -throughput!(medium_1MB, medium(), 1<<20); - -throughput!(hard_32, hard(), 32); -throughput!(hard_1K, hard(), 1<<10); -throughput!(hard_32K,hard(), 32<<10); -throughput!(hard_1MB, hard(), 1<<20); diff --git a/regex_macros/benches/random.txt b/regex_macros/benches/random.txt deleted file mode 100644 index dfae5cd142..0000000000 --- a/regex_macros/benches/random.txt +++ /dev/null @@ -1,513 +0,0 @@ - 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Do not use. #[plugin_registrar] @@ -68,22 +67,21 @@ fn native(cx: &mut ExtCtxt, sp: codemap::Span, tts: &[ast::TokenTree]) }; // We use the largest possible size limit because this is happening at // compile time. We trust the programmer. - let re = match Regex::with_size_limit(::std::usize::MAX, ®ex) { + let bprog = ProgramBuilder::new(®ex).size_limit(::std::usize::MAX); + let prog = match bprog.compile() { Ok(re) => re, Err(err) => { cx.span_err(sp, &err.to_string()); return DummyResult::any(sp) } }; - let prog = match re { - Dynamic(ref prog) => prog.clone(), - Native(_) => unreachable!(), - }; - + let names = prog.cap_names.iter().cloned().collect(); let mut gen = NfaGen { - cx: &*cx, sp: sp, prog: prog, - names: re.capture_names().map(|o| o.map(|s| s.to_owned())).collect(), - original: re.as_str().to_string(), + cx: &*cx, + sp: sp, + prog: prog, + names: names, + original: regex, }; MacEager::expr(gen.code()) } @@ -307,7 +305,7 @@ fn exec<'t>( } } -::regex::internal::Native(::regex::internal::ExNative { +::regex::Regex::Native(::regex::internal::ExNative { original: $regex, names: &CAP_NAMES, prog: exec, @@ -325,8 +323,8 @@ fn exec<'t>( match inst.look { EmptyLook::StartLine => { quote_expr!(self.cx, { - let prev = self.input.previous_at(at.pos()); - if prev.char().is_none() || prev.char() == '\n' { + let prev = self.input.previous_char(at); + if prev.is_none() || prev == '\n' { self.add(nlist, thread_caps, $nextpc, at); } }) @@ -340,8 +338,8 @@ fn exec<'t>( } EmptyLook::StartText => { quote_expr!(self.cx, { - let prev = self.input.previous_at(at.pos()); - if prev.char().is_none() { + let prev = self.input.previous_char(at); + if prev.is_none() { self.add(nlist, thread_caps, $nextpc, at); } }) @@ -361,8 +359,8 @@ fn exec<'t>( quote_expr!(self.cx, { !(w1 ^ w2) }) }; quote_expr!(self.cx, { - let prev = self.input.previous_at(at.pos()); - let w1 = prev.char().is_word_char(); + let prev = self.input.previous_char(at); + let w1 = prev.is_word_char(); let w2 = at.char().is_word_char(); if $m { self.add(nlist, thread_caps, $nextpc, at); diff --git a/src/backtrack.rs b/src/backtrack.rs index 1388a1b4ed..7b811d8b4c 100644 --- a/src/backtrack.rs +++ b/src/backtrack.rs @@ -16,56 +16,60 @@ // case linear time by keeping track of the states that is has visited (using a // bitmap). Namely, once a state is visited, it is never visited again. Since a // state is keyed by `(instruction index, input index)`, we have that its time -// complexity is `O(mn)`. +// complexity is `O(mn)` (i.e., linear in the size of the search text). // // The backtracking engine can beat out the NFA simulation on small // regexes/inputs because it doesn't have to keep track of multiple copies of // the capture groups. In benchmarks, the backtracking engine is roughly twice -// as fast as the full NFA simulation. +// as fast as the full NFA simulation. Note though that its performance doesn't +// scale, even if you're willing to live with the memory requirements. Namely, +// the bitset has to be zeroed on each execution, which becomes quite expensive +// on large bitsets. -use input::{Input, InputAt, CharInput}; -use inst::InstIdx; +use input::{Input, InputAt}; +use inst::InstPtr; use program::Program; use re::CaptureIdxs; -type Bits = u32; -const BIT_SIZE: usize = 32; -const MAX_PROG_SIZE: usize = 100; -const MAX_INPUT_SIZE: usize = 256 * (1 << 10); +/// Returns true iff the given regex and input should be executed by this +/// engine with reasonable memory usage. +pub fn should_exec(num_insts: usize, text_len: usize) -> bool { + num_insts <= MAX_PROG_SIZE && text_len <= MAX_INPUT_SIZE +} // Total memory usage in bytes is determined by: // -// ((len(insts) * (len(input) + 1) + bits - 1) / bits) / (bits / 8) +// ((len(insts) * (len(input) + 1) + bits - 1) / bits) * (size_of(u32)) // -// With the above settings, this comes out to ~3.2MB. Mostly these numbers +// With the contants below, this comes out to ~1.6MB. Mostly these numbers // were picked empirically with suspicious benchmarks. +type Bits = u32; +const BIT_SIZE: usize = 32; +const MAX_PROG_SIZE: usize = 100; +const MAX_INPUT_SIZE: usize = 128 * (1 << 10); + /// A backtracking matching engine. #[derive(Debug)] -pub struct Backtrack<'a, 'r, 't, 'c> { +pub struct Backtrack<'a, 'r, 'c, I> { prog: &'r Program, - input: CharInput<'t>, + input: I, caps: &'c mut CaptureIdxs, - m: &'a mut BackMachine, + m: &'a mut BacktrackCache, } /// Shared cached state between multiple invocations of a backtracking engine /// in the same thread. -/// -/// It is exported so that it can be cached by `program::Program`. #[derive(Debug)] -pub struct BackMachine { +pub struct BacktrackCache { jobs: Vec, visited: Vec, } -impl BackMachine { - /// Create new empty state for the backtracking engine. - pub fn new() -> BackMachine { - BackMachine { - jobs: vec![], - visited: vec![], - } +impl BacktrackCache { + /// Create new empty cache for the backtracking engine. + pub fn new() -> Self { + BacktrackCache { jobs: vec![], visited: vec![] } } } @@ -77,11 +81,11 @@ impl BackMachine { /// stack to do it. #[derive(Clone, Copy, Debug)] enum Job { - Inst { pc: InstIdx, at: InputAt }, + Inst { ip: InstPtr, at: InputAt }, SaveRestore { slot: usize, old_pos: Option }, } -impl<'a, 'r, 't, 'c> Backtrack<'a, 'r, 't, 'c> { +impl<'a, 'r, 'c, I: Input> Backtrack<'a, 'r, 'c, I> { /// Execute the backtracking matching engine. /// /// If there's a match, `exec` returns `true` and populates the given @@ -89,12 +93,11 @@ impl<'a, 'r, 't, 'c> Backtrack<'a, 'r, 't, 'c> { pub fn exec( prog: &'r Program, mut caps: &mut CaptureIdxs, - text: &'t str, + input: I, start: usize, ) -> bool { - let input = CharInput::new(text); let start = input.at(start); - let mut m = prog.backtrack.get(); + let mut m = prog.cache_backtrack(); let mut b = Backtrack { prog: prog, input: input, @@ -104,15 +107,11 @@ impl<'a, 'r, 't, 'c> Backtrack<'a, 'r, 't, 'c> { b.exec_(start) } - /// Returns true iff the given regex and input can be executed by this - /// engine with reasonable memory usage. - pub fn should_exec(prog: &'r Program, input: &str) -> bool { - prog.insts.len() <= MAX_PROG_SIZE && input.len() <= MAX_INPUT_SIZE - } - + /// Clears the cache such that the backtracking engine can be executed + /// on some input of fixed length. fn clear(&mut self) { // Reset the job memory so that we start fresh. - self.m.jobs.truncate(0); + self.m.jobs.clear(); // Now we need to clear the bit state set. // We do this by figuring out how much space we need to keep track @@ -141,16 +140,17 @@ impl<'a, 'r, 't, 'c> Backtrack<'a, 'r, 't, 'c> { } } + /// Start backtracking at the given position in the input, but also look + /// for literal prefixes. fn exec_(&mut self, mut at: InputAt) -> bool { self.clear(); + // If this is an anchored regex at the beginning of the input, then + // we're either already done or we only need to try backtracking once. if self.prog.anchored_begin { return if !at.is_beginning() { false } else { - match self.input.prefix_at(&self.prog.prefixes, at) { - None => false, - Some(at) => self.backtrack(at), - } + self.backtrack(at) }; } loop { @@ -163,22 +163,27 @@ impl<'a, 'r, 't, 'c> Backtrack<'a, 'r, 't, 'c> { if self.backtrack(at) { return true; } - if at.char().is_none() { + if at.is_end() { return false; } at = self.input.at(at.next_pos()); } } + /// The main backtracking loop starting at the given input position. // This `inline(always)` seems to result in about a 10-15% increase in // throughput on the `hard` benchmarks (over a standard `inline`). ---AG #[inline(always)] fn backtrack(&mut self, start: InputAt) -> bool { - self.push(0, start); + // N.B. We use an explicit stack to avoid recursion. + // To avoid excessive pushing and popping, most transitions are handled + // in the `step` helper function, which only pushes to the stack when + // there's a capture or a branch. + self.m.jobs.push(Job::Inst { ip: 0, at: start }); while let Some(job) = self.m.jobs.pop() { match job { - Job::Inst { pc, at } => { - if self.step(pc, at) { + Job::Inst { ip, at } => { + if self.step(ip, at) { return true; } } @@ -190,14 +195,14 @@ impl<'a, 'r, 't, 'c> Backtrack<'a, 'r, 't, 'c> { false } - fn step(&mut self, mut pc: InstIdx, mut at: InputAt) -> bool { + fn step(&mut self, mut ip: InstPtr, mut at: InputAt) -> bool { use inst::Inst::*; loop { // This loop is an optimization to avoid constantly pushing/popping // from the stack. Namely, if we're pushing a job only to run it - // next, avoid the push and just mutate `pc` (and possibly `at`) + // next, avoid the push and just mutate `ip` (and possibly `at`) // in place. - match self.prog.insts[pc] { + match self.prog.insts[ip] { Match => return true, Save(ref inst) => { if inst.slot < self.caps.len() { @@ -206,26 +211,30 @@ impl<'a, 'r, 't, 'c> Backtrack<'a, 'r, 't, 'c> { // job. If the next path fails, then the alternate // job is popped and the old capture index is restored. let old_pos = self.caps[inst.slot]; - self.push_save_restore(inst.slot, old_pos); + self.m.jobs.push(Job::SaveRestore { + slot: inst.slot, + old_pos: old_pos, + }); self.caps[inst.slot] = Some(at.pos()); } - pc = inst.goto; + ip = inst.goto; } Split(ref inst) => { - self.push(inst.goto2, at); - pc = inst.goto1; + self.m.jobs.push(Job::Inst { ip: inst.goto2, at: at }); + ip = inst.goto1; } EmptyLook(ref inst) => { - let prev = self.input.previous_at(at.pos()); - if inst.matches(prev.char(), at.char()) { - pc = inst.goto; + let prev = self.input.previous_char(at); + let next = self.input.next_char(at); + if inst.matches(prev, next) { + ip = inst.goto; } else { return false; } } Char(ref inst) => { if inst.c == at.char() { - pc = inst.goto; + ip = inst.goto; at = self.input.at(at.next_pos()); } else { return false; @@ -233,31 +242,33 @@ impl<'a, 'r, 't, 'c> Backtrack<'a, 'r, 't, 'c> { } Ranges(ref inst) => { if inst.matches(at.char()) { - pc = inst.goto; + ip = inst.goto; at = self.input.at(at.next_pos()); } else { return false; } } + Bytes(ref inst) => { + if let Some(b) = at.byte() { + if inst.matches(b) { + ip = inst.goto; + at = self.input.at(at.next_pos()); + continue; + } + } + return false; + } } - if self.has_visited(pc, at) { + if self.has_visited(ip, at) { return false; } } } - fn push(&mut self, pc: InstIdx, at: InputAt) { - self.m.jobs.push(Job::Inst { pc: pc, at: at }); - } - - fn push_save_restore(&mut self, slot: usize, old_pos: Option) { - self.m.jobs.push(Job::SaveRestore { slot: slot, old_pos: old_pos }); - } - - fn has_visited(&mut self, pc: InstIdx, at: InputAt) -> bool { - let k = pc * (self.input.len() + 1) + at.pos(); + fn has_visited(&mut self, ip: InstPtr, at: InputAt) -> bool { + let k = ip * (self.input.len() + 1) + at.pos(); let k1 = k / BIT_SIZE; - let k2 = (1 << (k & (BIT_SIZE - 1))) as Bits; + let k2 = usize_to_u32(1 << (k & (BIT_SIZE - 1))); if self.m.visited[k1] & k2 == 0 { self.m.visited[k1] |= k2; false @@ -266,3 +277,10 @@ impl<'a, 'r, 't, 'c> Backtrack<'a, 'r, 't, 'c> { } } } + +fn usize_to_u32(n: usize) -> u32 { + if (n as u64) > (::std::u32::MAX as u64) { + panic!("BUG: {} is too big to fit into u32", n) + } + n as u32 +} diff --git a/src/char_utf8.rs b/src/char_utf8.rs new file mode 100644 index 0000000000..ac6be54908 --- /dev/null +++ b/src/char_utf8.rs @@ -0,0 +1,36 @@ +// Pulled from std::char until encode_utf8 stabilizes. ---AG + +// UTF-8 ranges and tags for encoding characters +const TAG_CONT: u8 = 0b1000_0000; +const TAG_TWO_B: u8 = 0b1100_0000; +const TAG_THREE_B: u8 = 0b1110_0000; +const TAG_FOUR_B: u8 = 0b1111_0000; +const MAX_ONE_B: u32 = 0x80; +const MAX_TWO_B: u32 = 0x800; +const MAX_THREE_B: u32 = 0x10000; + +#[inline] +pub fn encode_utf8(character: char, dst: &mut [u8]) -> Option { + let code = character as u32; + if code < MAX_ONE_B && !dst.is_empty() { + dst[0] = code as u8; + Some(1) + } else if code < MAX_TWO_B && dst.len() >= 2 { + dst[0] = (code >> 6 & 0x1F) as u8 | TAG_TWO_B; + dst[1] = (code & 0x3F) as u8 | TAG_CONT; + Some(2) + } else if code < MAX_THREE_B && dst.len() >= 3 { + dst[0] = (code >> 12 & 0x0F) as u8 | TAG_THREE_B; + dst[1] = (code >> 6 & 0x3F) as u8 | TAG_CONT; + dst[2] = (code & 0x3F) as u8 | TAG_CONT; + Some(3) + } else if dst.len() >= 4 { + dst[0] = (code >> 18 & 0x07) as u8 | TAG_FOUR_B; + dst[1] = (code >> 12 & 0x3F) as u8 | TAG_CONT; + dst[2] = (code >> 6 & 0x3F) as u8 | TAG_CONT; + dst[3] = (code & 0x3F) as u8 | TAG_CONT; + Some(4) + } else { + None + } +} diff --git a/src/compile.rs b/src/compile.rs index 36a1d3c7cc..84438e6cc4 100644 --- a/src/compile.rs +++ b/src/compile.rs @@ -10,67 +10,183 @@ use std::collections::HashSet; use std::iter; +use std::result; use syntax::{Expr, Repeater, CharClass, ClassRange}; +use utf8_ranges::{Utf8Range, Utf8Sequence, Utf8Sequences}; use Error; use inst::{ - EmptyLook, - Inst, InstIdx, - InstSave, InstSplit, InstEmptyLook, InstChar, InstRanges, + Insts, Inst, InstPtr, EmptyLook, + InstSave, InstSplit, InstEmptyLook, InstChar, InstRanges, InstBytes, }; -pub type Compiled = (Vec, Vec>); +pub struct Compiled { + pub insts: Insts, + pub cap_names: Vec>, +} + +type InstHoleIdx = InstPtr; + +type Result = result::Result; -type CompileResult = Result; +#[derive(Debug)] +struct Patch { + hole: Hole, + entry: InstPtr, +} pub struct Compiler { - size_limit: usize, insts: Vec, cap_names: Vec>, seen_caps: HashSet, + size_limit: usize, + bytes: bool, + dfa: bool, + reverse: bool, + suffix_cache: SuffixCache, + utf8_seqs: Option, + byte_classes: ByteClassSet, } impl Compiler { - pub fn new(size_limit: usize) -> Compiler { + /// Create a new regular expression compiler. + /// + /// Various options can be set before calling `compile` on an expression. + pub fn new() -> Self { Compiler { - size_limit: size_limit, insts: vec![], cap_names: vec![None], seen_caps: HashSet::new(), + size_limit: 10 * (1 << 20), + bytes: false, + dfa: false, + reverse: false, + suffix_cache: SuffixCache::new(1000), + utf8_seqs: Some(Utf8Sequences::new('\x00', '\x00')), + byte_classes: ByteClassSet::new(), } } - pub fn compile(mut self, expr: &Expr) -> Result { - let hole = try!(self.c_capture(0, expr)); - self.fill_to_next(hole); + /// The size of the resulting program is limited by size_limit. If + /// the program approximately exceeds the given size (in bytes), then + /// compilation will stop and return an error. + pub fn size_limit(mut self, size_limit: usize) -> Self { + self.size_limit = size_limit; + self + } + + /// If bytes is true, then the program is compiled as a byte based + /// automaton, which incorporates UTF-8 decoding into the machine. If it's + /// false, then the automaton is Unicode scalar value based, e.g., an + /// engine utilizing such an automaton is resposible for UTF-8 decoding. + /// + /// The specific invariant is that when returning a byte based machine, + /// the neither the `Char` nor `Ranges` instructions are produced. + /// Conversely, when producing a Unicode scalar value machine, the `Bytes` + /// instruction is never produced. + /// + /// Note that `dfa(true)` implies `bytes(true)`. + pub fn bytes(mut self, yes: bool) -> Self { + self.bytes = yes; + self + } + + /// When set, the machine returned is suitable for use in the DFA matching + /// engine. + /// + /// In particular, this ensures that if the regex is not anchored in the + /// beginning, then a preceding `.*?` is included in the program. (The NFA + /// based engines handle the preceding `.*?` explicitly, which is difficult + /// or impossible in the DFA engine.) + pub fn dfa(mut self, yes: bool) -> Self { + self.dfa = yes; + self.bytes = yes; + self + } + + /// When set, the machine returned is suitable for matching text in + /// reverse. In particular, all concatenations are flipped. + pub fn reverse(mut self, yes: bool) -> Self { + self.reverse = yes; + self + } + + /// Compile a regular expression given its AST. + /// + /// The compiler is guaranteed to succeed unless the program exceeds the + /// specified size limit. If the size limit is exceeded, then compilation + /// stops and returns an error. + pub fn compile(mut self, expr: &Expr) -> result::Result { + if self.dfa && !self.reverse && !expr.is_anchored_start() { + let patch = try!(self.c(&Expr::Repeat { + e: Box::new(Expr::AnyChar), + r: Repeater::ZeroOrMore, + greedy: false, + })); + self.fill_to_next(patch.hole); + } + let patch = try!(self.c_capture(0, expr)); + self.fill_to_next(patch.hole); self.push_compiled(Inst::Match); + let byte_classes = self.byte_classes.byte_classes(); let insts = self.insts.into_iter().map(|inst| inst.unwrap()).collect(); - Ok((insts, self.cap_names)) + Ok(Compiled { + insts: Insts::new(insts, self.bytes, self.reverse, byte_classes), + cap_names: self.cap_names, + }) } - fn c(&mut self, expr: &Expr) -> CompileResult { + fn c(&mut self, expr: &Expr) -> Result { use inst; use syntax::Expr::*; try!(self.check_size()); match *expr { - Empty => Ok(Hole::None), + Empty => Ok(Patch { hole: Hole::None, entry: self.insts.len() }), Literal { ref chars, casei } => self.c_literal(chars, casei), - AnyChar => self.c_class(Some(('\x00', '\u{10ffff}'))), + AnyChar => self.c_class(&[ClassRange { + start: '\x00', + end: '\u{10ffff}', + }]), AnyCharNoNL => { - let ranges = &[('\x00', '\x09'), ('\x0b', '\u{10ffff}')]; - self.c_class(ranges.iter().cloned()) + self.c_class(&[ + ClassRange { start: '\x00', end: '\x09' }, + ClassRange { start: '\x0b', end: '\u{10ffff}' }, + ]) } Class(ref cls) => { - let ranges = cls.iter().map(|c| (c.start, c.end)); - self.c_class(ranges) + self.c_class(cls) + } + StartLine if self.reverse => { + self.byte_classes.set_range(b'\n', b'\n'); + self.c_empty_look(inst::EmptyLook::EndLine) + } + StartLine => { + self.byte_classes.set_range(b'\n', b'\n'); + self.c_empty_look(inst::EmptyLook::StartLine) + } + EndLine if self.reverse => { + self.byte_classes.set_range(b'\n', b'\n'); + self.c_empty_look(inst::EmptyLook::StartLine) + } + EndLine => { + self.byte_classes.set_range(b'\n', b'\n'); + self.c_empty_look(inst::EmptyLook::EndLine) + } + StartText if self.reverse => { + self.c_empty_look(inst::EmptyLook::EndText) + } + StartText => { + self.c_empty_look(inst::EmptyLook::StartText) + } + EndText if self.reverse => { + self.c_empty_look(inst::EmptyLook::StartText) + } + EndText => { + self.c_empty_look(inst::EmptyLook::EndText) } - StartLine => self.c_empty_look(inst::EmptyLook::StartLine), - EndLine => self.c_empty_look(inst::EmptyLook::EndLine), - StartText => self.c_empty_look(inst::EmptyLook::StartText), - EndText => self.c_empty_look(inst::EmptyLook::EndText), WordBoundary => self.c_empty_look(inst::EmptyLook::WordBoundary), NotWordBoundary => { self.c_empty_look(inst::EmptyLook::NotWordBoundary) @@ -85,80 +201,118 @@ impl Compiler { } self.c_capture(2 * i, e) } - Concat(ref es) => self.c_concat(es.iter()), + Concat(ref es) => { + if self.reverse { + self.c_concat(es.iter().rev()) + } else { + self.c_concat(es) + } + } Alternate(ref es) => self.c_alternate(&**es), Repeat { ref e, r, greedy } => self.c_repeat(e, r, greedy), } } - fn c_capture(&mut self, first_slot: usize, expr: &Expr) -> CompileResult { - let hole = self.push_hole(MaybeInst::Save { slot: first_slot }); - self.fill_to_next(hole); - - let hole = try!(self.c(expr)); - self.fill_to_next(hole); - - Ok(self.push_hole(MaybeInst::Save { slot: first_slot + 1 })) + fn c_capture(&mut self, first_slot: usize, expr: &Expr) -> Result { + let entry = self.insts.len(); + let hole = self.push_hole(InstHole::Save { slot: first_slot }); + let patch = try!(self.c(expr)); + self.fill(hole, patch.entry); + self.fill_to_next(patch.hole); + let hole = self.push_hole(InstHole::Save { slot: first_slot + 1 }); + Ok(Patch { hole: hole, entry: entry }) } - fn c_literal(&mut self, chars: &[char], casei: bool) -> CompileResult { + fn c_literal(&mut self, chars: &[char], casei: bool) -> Result { assert!(!chars.is_empty()); + let mut chars: Box> = if self.reverse { + Box::new(chars.iter().rev()) + } else { + Box::new(chars.iter()) + }; + let first = *chars.next().expect("non-empty literal"); + let Patch { mut hole, entry } = try!(self.c_char(first, casei)); + for &c in chars { + let p = try!(self.c_char(c, casei)); + self.fill(hole, p.entry); + hole = p.hole; + } + Ok(Patch { hole: hole, entry: entry }) + } + + fn c_char(&mut self, c: char, casei: bool) -> Result { if casei { - let mut prev_hole = Hole::None; - for &c in chars { - self.fill_to_next(prev_hole); - let class = CharClass::new(vec![ - ClassRange { start: c, end: c }, - ]); - prev_hole = try!(self.c(&Expr::Class(class.case_fold()))); - } - Ok(prev_hole) + self.c_class(&CharClass::new(vec![ + ClassRange { start: c, end: c }, + ]).case_fold()) } else { - let mut prev_hole = Hole::None; - for &c in chars { - self.fill_to_next(prev_hole); - prev_hole = self.push_hole(MaybeInst::Char { c: c }); - } - Ok(prev_hole) + self.c_class(&[ClassRange { start: c, end: c }]) } } - fn c_class(&mut self, ranges: I) -> CompileResult - where I: IntoIterator { - let ranges: Vec<(char, char)> = ranges.into_iter().collect(); - Ok(if ranges.len() == 1 && ranges[0].0 == ranges[0].1 { - self.push_hole(MaybeInst::Char { c: ranges[0].0 }) + fn c_class(&mut self, ranges: &[ClassRange]) -> Result { + if self.bytes { + CompileClass { + c: self, + ranges: ranges, + }.compile() } else { - self.push_hole(MaybeInst::Ranges { ranges: ranges }) - }) + let ranges: Vec<(char, char)> = + ranges.iter().map(|r| (r.start, r.end)).collect(); + let hole = if ranges.len() == 1 && ranges[0].0 == ranges[0].1 { + self.push_hole(InstHole::Char { c: ranges[0].0 }) + } else { + self.push_hole(InstHole::Ranges { ranges: ranges }) + }; + Ok(Patch { hole: hole, entry: self.insts.len() - 1 }) + } } - fn c_empty_look(&mut self, look: EmptyLook) -> CompileResult { - Ok(self.push_hole(MaybeInst::EmptyLook { look: look })) + fn c_empty_look(&mut self, look: EmptyLook) -> Result { + let hole = self.push_hole(InstHole::EmptyLook { look: look }); + Ok(Patch { hole: hole, entry: self.insts.len() - 1 }) } - fn c_concat<'a, I>(&mut self, exprs: I) -> CompileResult + fn c_concat<'a, I>(&mut self, exprs: I) -> Result where I: IntoIterator { - let mut prev_hole = Hole::None; + let mut exprs = exprs.into_iter(); + let first = match exprs.next() { + Some(expr) => expr, + None => { + return Ok(Patch { hole: Hole::None, entry: self.insts.len() }) + } + }; + let Patch { mut hole, entry } = try!(self.c(first)); for e in exprs { - self.fill_to_next(prev_hole); - prev_hole = try!(self.c(e)); + let p = try!(self.c(e)); + self.fill(hole, p.entry); + hole = p.hole; } - Ok(prev_hole) + Ok(Patch { hole: hole, entry: entry }) } - fn c_alternate(&mut self, exprs: &[Expr]) -> CompileResult { + fn c_alternate(&mut self, exprs: &[Expr]) -> Result { assert!(exprs.len() >= 2, "alternates must have at least 2 exprs"); + + // Initial entry point is always the first split. + let first_split_entry = self.insts.len(); + + // Save up all of the holes from each alternate. They will all get + // patched to point to the same location. let mut holes = vec![]; + + let mut prev_hole = Hole::None; for e in &exprs[0..exprs.len() - 1] { + self.fill_to_next(prev_hole); let split = self.push_split_hole(); - let goto1 = self.insts.len(); - holes.push(try!(self.c(e))); - let goto2 = self.insts.len(); - self.fill_split(split, Some(goto1), Some(goto2)); + let Patch { hole, entry } = try!(self.c(e)); + holes.push(hole); + prev_hole = self.fill_split(split, Some(entry), None); } - holes.push(try!(self.c(&exprs[exprs.len() - 1]))); - Ok(Hole::Many(holes)) + let Patch { hole, entry } = try!(self.c(&exprs[exprs.len() - 1])); + holes.push(hole); + self.fill(prev_hole, entry); + Ok(Patch { hole: Hole::Many(holes), entry: first_split_entry }) } fn c_repeat( @@ -166,7 +320,7 @@ impl Compiler { expr: &Expr, kind: Repeater, greedy: bool, - ) -> CompileResult { + ) -> Result { match kind { Repeater::ZeroOrOne => self.c_repeat_zero_or_one(expr, greedy), Repeater::ZeroOrMore => self.c_repeat_zero_or_more(expr, greedy), @@ -184,52 +338,53 @@ impl Compiler { &mut self, expr: &Expr, greedy: bool, - ) -> CompileResult { + ) -> Result { + let split_entry = self.insts.len(); let split = self.push_split_hole(); - let goto1 = self.insts.len(); - let hole1 = try!(self.c(expr)); + let Patch { hole: hole_rep, entry: entry_rep } = try!(self.c(expr)); - let hole2 = if greedy { - self.fill_split(split, Some(goto1), None) + let split_hole = if greedy { + self.fill_split(split, Some(entry_rep), None) } else { - self.fill_split(split, None, Some(goto1)) + self.fill_split(split, None, Some(entry_rep)) }; - Ok(Hole::Many(vec![hole1, hole2])) + let holes = vec![hole_rep, split_hole]; + Ok(Patch { hole: Hole::Many(holes), entry: split_entry }) } fn c_repeat_zero_or_more( &mut self, expr: &Expr, greedy: bool, - ) -> CompileResult { - let goto_split = self.insts.len(); + ) -> Result { + let split_entry = self.insts.len(); let split = self.push_split_hole(); - let goto_rep_expr = self.insts.len(); - let hole_rep_expr = try!(self.c(expr)); + let Patch { hole: hole_rep, entry: entry_rep } = try!(self.c(expr)); - self.fill(hole_rep_expr, goto_split); - Ok(if greedy { - self.fill_split(split, Some(goto_rep_expr), None) + self.fill(hole_rep, split_entry); + let split_hole = if greedy { + self.fill_split(split, Some(entry_rep), None) } else { - self.fill_split(split, None, Some(goto_rep_expr)) - }) + self.fill_split(split, None, Some(entry_rep)) + }; + Ok(Patch { hole: split_hole, entry: split_entry }) } fn c_repeat_one_or_more( &mut self, expr: &Expr, greedy: bool, - ) -> CompileResult { - let goto_rep_expr = self.insts.len(); - let hole_rep_expr = try!(self.c(expr)); - self.fill_to_next(hole_rep_expr); + ) -> Result { + let Patch { hole: hole_rep, entry: entry_rep } = try!(self.c(expr)); + self.fill_to_next(hole_rep); let split = self.push_split_hole(); - Ok(if greedy { - self.fill_split(split, Some(goto_rep_expr), None) + let split_hole = if greedy { + self.fill_split(split, Some(entry_rep), None) } else { - self.fill_split(split, None, Some(goto_rep_expr)) - }) + self.fill_split(split, None, Some(entry_rep)) + }; + Ok(Patch { hole: split_hole, entry: entry_rep }) } fn c_repeat_range_min_or_more( @@ -237,14 +392,12 @@ impl Compiler { expr: &Expr, greedy: bool, min: u32, - ) -> CompileResult { + ) -> Result { let min = u32_to_usize(min); - if min == 0 { - return self.c_repeat_zero_or_more(expr, greedy); - } - let hole = try!(self.c_concat(iter::repeat(expr).take(min - 1))); - self.fill_to_next(hole); - self.c_repeat_one_or_more(expr, greedy) + let patch_concat = try!(self.c_concat(iter::repeat(expr).take(min))); + let patch_rep = try!(self.c_repeat_zero_or_more(expr, greedy)); + self.fill(patch_concat.hole, patch_rep.entry); + Ok(Patch { hole: patch_rep.hole, entry: patch_concat.entry }) } fn c_repeat_range( @@ -253,13 +406,13 @@ impl Compiler { greedy: bool, min: u32, max: u32, - ) -> CompileResult { + ) -> Result { let (min, max) = (u32_to_usize(min), u32_to_usize(max)); - let hole = try!(self.c_concat(iter::repeat(expr).take(min))); + let patch_concat = try!(self.c_concat(iter::repeat(expr).take(min))); + let initial_entry = patch_concat.entry; if min == max { - return Ok(hole); + return Ok(patch_concat); } - self.fill_to_next(hole); // It is much simpler to compile, e.g., `a{2,5}` as: // // aaa?a?a? @@ -277,35 +430,30 @@ impl Compiler { // 8: MATCH // // This is *incredibly* inefficient because the splits end - // up forming a chain. Given a much larger number than `5`, - // it is easy cause perverse behavior in the matching engines - // like stack overflows. We could fix the matching engine, - // but instead, we should just make the program smarter. - // Thus, we do a custom job here and instead of chaining the - // splits together, we simply point them to the MATCH - // instruction directly (for example). + // up forming a chain, which has to be resolved everything a + // transition is followed. let mut holes = vec![]; - let mut prev_hole = Hole::None; + let mut prev_hole = patch_concat.hole; for _ in min..max { self.fill_to_next(prev_hole); let split = self.push_split_hole(); - let goto_rep_expr = self.insts.len(); - prev_hole = try!(self.c(expr)); + let Patch { hole, entry } = try!(self.c(expr)); + prev_hole = hole; if greedy { - holes.push(self.fill_split(split, Some(goto_rep_expr), None)); + holes.push(self.fill_split(split, Some(entry), None)); } else { - holes.push(self.fill_split(split, None, Some(goto_rep_expr))); + holes.push(self.fill_split(split, None, Some(entry))); } } holes.push(prev_hole); - Ok(Hole::Many(holes)) + Ok(Patch { hole: Hole::Many(holes), entry: initial_entry }) } - fn fill(&mut self, hole: Hole, goto: InstIdx) { + fn fill(&mut self, hole: Hole, goto: InstPtr) { match hole { Hole::None => {} Hole::One(pc) => { - self.insts[pc].complete(goto); + self.insts[pc].fill(goto); } Hole::Many(holes) => { for hole in holes { @@ -323,23 +471,23 @@ impl Compiler { fn fill_split( &mut self, hole: Hole, - goto1: Option, - goto2: Option, + goto1: Option, + goto2: Option, ) -> Hole { match hole { Hole::None => Hole::None, Hole::One(pc) => { match (goto1, goto2) { (Some(goto1), Some(goto2)) => { - self.insts[pc].complete_split(goto1, goto2); + self.insts[pc].fill_split(goto1, goto2); Hole::None } (Some(goto1), None) => { - self.insts[pc].complete_split_goto1(goto1); + self.insts[pc].half_fill_split_goto1(goto1); Hole::One(pc) } (None, Some(goto2)) => { - self.insts[pc].complete_split_goto2(goto2); + self.insts[pc].half_fill_split_goto2(goto2); Hole::One(pc) } (None, None) => unreachable!("at least one of the split \ @@ -366,9 +514,9 @@ impl Compiler { self.insts.push(MaybeInst::Compiled(inst)); } - fn push_hole(&mut self, inst: MaybeInst) -> Hole { + fn push_hole(&mut self, inst: InstHole) -> Hole { let hole = self.insts.len(); - self.insts.push(inst); + self.insts.push(MaybeInst::Uncompiled(inst)); Hole::One(hole) } @@ -378,7 +526,7 @@ impl Compiler { Hole::One(hole) } - fn check_size(&self) -> Result<(), Error> { + fn check_size(&self) -> result::Result<(), Error> { use std::mem::size_of; if self.insts.len() * size_of::() > self.size_limit { @@ -389,89 +537,39 @@ impl Compiler { } } -/// Hole represents a pointer to zero or more instructions in a regex program -/// that need to have their goto fields set to the same location. #[derive(Debug)] enum Hole { None, - One(InstIdx), + One(InstPtr), Many(Vec), } -/// MaybeInst represents a possibly incomplete instruction in a regex program. -/// The nature of incompleteness is always determined by whether the -/// instruction's "goto" field has been set or not. -/// -/// In the case of Split, since it has two goto fields, it can be "incomplete" -/// in three different ways: either none of its fields are set, only the first -/// is set or only the second is set. The reason why the first and second -/// fields are distinguished is because the order of the branch matters. (i.e., -/// it's how "greedy" and "ungreedy" semantics are implemented.) -/// -/// When the compiler is finished, *all* of its possibly incomplete -/// instructions must have been fully compiled where all goto fields in all -/// instructions are set. Violation of this invariant is a bug. #[derive(Clone, Debug)] enum MaybeInst { - /// Compiled represents an instruction that is fully compiled. That is, - /// all of its "goto" fields have been filled. When the compiler is done, - /// all MaybeInsts must be of the Compiled form. Compiled(Inst), - /// Split is a branch instruction where neither of its goto fields have - /// been set. + Uncompiled(InstHole), Split, - /// Split1 is a branch instruction where only the first goto field has - /// been set. - Split1(InstIdx), - /// Split2 is a branch instruction where only the second goto field has - /// been set. - Split2(InstIdx), - /// Save is a capture instruction whose goto field has not been set. - Save { slot: usize }, - /// EmptyLook is a zero-width assertion instruction whose goto field has - /// not been set. - EmptyLook { look: EmptyLook }, - /// Char is a character-match instruction whose goto field has not been - /// set. - Char { c: char }, - /// Ranges is a character-range-match instruction whose goto field has not - /// been set. - Ranges { ranges: Vec<(char, char)> }, + Split1(InstPtr), + Split2(InstPtr), } impl MaybeInst { - fn complete(&mut self, goto: InstIdx) { + fn fill(&mut self, goto: InstPtr) { let filled = match *self { - MaybeInst::Save { slot } => Inst::Save(InstSave { - goto: goto, - slot: slot, - }), - MaybeInst::EmptyLook { look } => Inst::EmptyLook(InstEmptyLook { - goto: goto, - look: look, - }), - MaybeInst::Char { c } => Inst::Char(InstChar { - goto: goto, - c: c, - }), - MaybeInst::Ranges { ref ranges } => Inst::Ranges(InstRanges { - goto: goto, - ranges: ranges.clone(), - }), + MaybeInst::Uncompiled(ref inst) => inst.fill(goto), MaybeInst::Split1(goto1) => { Inst::Split(InstSplit { goto1: goto1, goto2: goto }) } MaybeInst::Split2(goto2) => { Inst::Split(InstSplit { goto1: goto, goto2: goto2 }) } - _ => unreachable!("must be called on an uncompiled instruction \ - with exactly one missing goto field, \ - instead it was called on: {:?}", self), + _ => unreachable!("not all instructions were compiled! \ + found uncompiled instruction: {:?}", self), }; *self = MaybeInst::Compiled(filled); } - fn complete_split(&mut self, goto1: InstIdx, goto2: InstIdx) { + fn fill_split(&mut self, goto1: InstPtr, goto2: InstPtr) { let filled = match *self { MaybeInst::Split => { Inst::Split(InstSplit { goto1: goto1, goto2: goto2 }) @@ -482,7 +580,7 @@ impl MaybeInst { *self = MaybeInst::Compiled(filled); } - fn complete_split_goto1(&mut self, goto1: InstIdx) { + fn half_fill_split_goto1(&mut self, goto1: InstPtr) { let half_filled = match *self { MaybeInst::Split => goto1, _ => unreachable!("must be called on Split instruction, \ @@ -491,7 +589,7 @@ impl MaybeInst { *self = MaybeInst::Split1(half_filled); } - fn complete_split_goto2(&mut self, goto2: InstIdx) { + fn half_fill_split_goto2(&mut self, goto2: InstPtr) { let half_filled = match *self { MaybeInst::Split => goto2, _ => unreachable!("must be called on Split instruction, \ @@ -509,9 +607,291 @@ impl MaybeInst { } } +#[derive(Clone, Debug)] +enum InstHole { + Save { slot: usize }, + EmptyLook { look: EmptyLook }, + Char { c: char }, + Ranges { ranges: Vec<(char, char)> }, + Bytes { start: u8, end: u8 }, +} + +impl InstHole { + fn fill(&self, goto: InstPtr) -> Inst { + match *self { + InstHole::Save { slot } => Inst::Save(InstSave { + goto: goto, + slot: slot, + }), + InstHole::EmptyLook { look } => Inst::EmptyLook(InstEmptyLook { + goto: goto, + look: look, + }), + InstHole::Char { c } => Inst::Char(InstChar { + goto: goto, + c: c, + }), + InstHole::Ranges { ref ranges } => Inst::Ranges(InstRanges { + goto: goto, + ranges: ranges.clone(), + }), + InstHole::Bytes { start, end } => Inst::Bytes(InstBytes { + goto: goto, + start: start, + end: end, + }), + } + } +} + +struct CompileClass<'a, 'b> { + c: &'a mut Compiler, + ranges: &'b [ClassRange], +} + +impl<'a, 'b> CompileClass<'a, 'b> { + fn compile(mut self) -> Result { + let mut holes = vec![]; + let mut initial_entry = None; + let mut last_split = Hole::None; + let mut utf8_seqs = self.c.utf8_seqs.take().unwrap(); + self.c.suffix_cache.clear(); + + for (i, ref range) in self.ranges.iter().enumerate() { + let is_last_range = i + 1 == self.ranges.len(); + utf8_seqs.reset(range.start, range.end); + let mut it = (&mut utf8_seqs).peekable(); + loop { + let utf8_seq = match it.next() { + None => break, + Some(utf8_seq) => utf8_seq, + }; + if is_last_range && it.peek().is_none() { + let Patch { hole, entry } = try!(self.c_utf8_seq(&utf8_seq)); + holes.push(hole); + self.c.fill(last_split, entry); + last_split = Hole::None; + if initial_entry.is_none() { + initial_entry = Some(entry); + } + } else { + if initial_entry.is_none() { + initial_entry = Some(self.c.insts.len()); + } + self.c.fill_to_next(last_split); + last_split = self.c.push_split_hole(); + let Patch { hole, entry } = try!(self.c_utf8_seq(&utf8_seq)); + holes.push(hole); + last_split = self.c.fill_split(last_split, Some(entry), None); + } + } + } + self.c.utf8_seqs = Some(utf8_seqs); + Ok(Patch { + hole: Hole::Many(holes), + entry: initial_entry.unwrap(), + }) + } + + fn c_utf8_seq(&mut self, seq: &Utf8Sequence) -> Result { + if self.c.reverse { + self.c_utf8_seq_(seq) + } else { + self.c_utf8_seq_(seq.into_iter().rev()) + } + } + + fn c_utf8_seq_<'r, I>(&mut self, seq: I) -> Result + where I: IntoIterator { + // The initial instruction for each UTF-8 sequence should be the same. + // Since the 0th instruction has always been created by this point, + // it's safe to use it as a sentinel here. + let mut from_inst = 0; + let mut last_hole = Hole::None; + for byte_range in seq { + let key = SuffixCacheKey { + from_inst: from_inst, + start: byte_range.start, + end: byte_range.end, + }; + { + let pc = self.c.insts.len(); + if let Some(cached_pc) = self.c.suffix_cache.get(key, pc) { + from_inst = cached_pc; + continue; + } + } + self.c.byte_classes.set_range(byte_range.start, byte_range.end); + if from_inst == 0 { + last_hole = self.c.push_hole(InstHole::Bytes { + start: byte_range.start, + end: byte_range.end, + }); + } else { + self.c.push_compiled(Inst::Bytes(InstBytes { + goto: from_inst, + start: byte_range.start, + end: byte_range.end, + })); + } + from_inst = self.c.insts.len().checked_sub(1).unwrap(); + } + assert!(from_inst > 0); + Ok(Patch { hole: last_hole, entry: from_inst }) + } +} + +/// SuffixCache is a simple bounded hash map for caching suffix entries in +/// UTF-8 automata. For example, consider the Unicode range \u{0}-\u{FFFF}. +/// The set of byte ranges looks like this: +/// +/// [0-7F] +/// [C2-DF][80-BF] +/// [E0][A0-BF][80-BF] +/// [E1-EC][80-BF][80-BF] +/// [ED][80-9F][80-BF] +/// [EE-EF][80-BF][80-BF] +/// +/// Each line above translates to one alternate in the compiled regex program. +/// However, all but one of the alternates end in the same suffix, which is +/// a waste of an instruction. The suffix cache facilitates reusing them across +/// alternates. +/// +/// Note that a HashMap could be trivially used for this, but we don't need its +/// overhead. Some small bounded space (LRU style) is more than enough. +struct SuffixCache { + table: Vec, + // Every time the cache is cleared, we increment the version number instead + // of actually zeroing memory. Since we store a copy of the current version + // in every element, all we need to do is make sure to invalidate any stale + // entries upon access. This saves quite a bit of time! + version: usize, +} + +#[derive(Clone, Copy, Debug, Default, Eq, Hash, PartialEq)] +struct SuffixCacheEntry { + key: SuffixCacheKey, + pc: InstPtr, + version: usize, +} + +#[derive(Clone, Copy, Debug, Default, Eq, Hash, PartialEq)] +struct SuffixCacheKey { + from_inst: InstPtr, + start: u8, + end: u8, +} + +impl SuffixCache { + fn new(size: usize) -> Self { + SuffixCache { + table: vec![SuffixCacheEntry::default(); size], + version: 0, + } + } + + fn get(&mut self, key: SuffixCacheKey, pc: InstPtr) -> Option { + let h = self.hash(&key); + let e = self.table[h]; + if e.key == key && e.version == self.version { + Some(e.pc) + } else { + self.table[h] = SuffixCacheEntry { + key: key, + pc: pc, + version: self.version, + }; + None + } + } + + fn clear(&mut self) { + self.version += 1; + } + + fn hash(&self, suffix: &SuffixCacheKey) -> usize { + // Basic FNV-1a hash as described: + // https://en.wikipedia.org/wiki/Fowler%E2%80%93Noll%E2%80%93Vo_hash_function + const FNV_PRIME: u64 = 1099511628211; + let mut h = 14695981039346656037; + h = (h ^ (suffix.from_inst as u64)).wrapping_mul(FNV_PRIME); + h = (h ^ (suffix.start as u64)).wrapping_mul(FNV_PRIME); + h = (h ^ (suffix.end as u64)).wrapping_mul(FNV_PRIME); + (h as usize) % self.table.len() + } +} + +struct ByteClassSet([bool; 256]); + +impl ByteClassSet { + fn new() -> Self { + ByteClassSet([false; 256]) + } + + fn set_range(&mut self, start: u8, end: u8) { + assert!(start <= end); + if start > 0 { + self.0[start as usize - 1] = true; + } + self.0[end as usize] = true; + } + + fn byte_classes(&self) -> Vec { + // N.B. If you're debugging the DFA, it's useful to simply return + // `(0..256).collect()`, which effectively removes the byte classes + // and makes the transitions easier to read. + // return (0..256).collect(); + let mut byte_classes = vec![0; 256]; + let mut class = 0; + for i in 0..256 { + byte_classes[i] = class; + if i > 0 && self.0[i] { + class += 1; + } + } + byte_classes + } +} + fn u32_to_usize(n: u32) -> usize { if (n as u64) > (::std::usize::MAX as u64) { panic!("BUG: {} is too big to be pointer sized", n) } n as usize } + +#[cfg(test)] +mod tests { + use super::ByteClassSet; + + #[test] + fn byte_classes() { + let mut set = ByteClassSet::new(); + set.set_range(b'a', b'z'); + let classes = set.byte_classes(); + assert_eq!(classes[0], 0); + assert_eq!(classes[1], 0); + assert_eq!(classes[2], 0); + assert_eq!(classes[b'a' as usize - 1], 0); + assert_eq!(classes[b'a' as usize], 1); + assert_eq!(classes[b'm' as usize], 1); + assert_eq!(classes[b'z' as usize], 1); + assert_eq!(classes[b'z' as usize + 1], 2); + assert_eq!(classes[254], 2); + assert_eq!(classes[255], 2); + + let mut set = ByteClassSet::new(); + set.set_range(0, 2); + set.set_range(4, 6); + let classes = set.byte_classes(); + assert_eq!(classes[0], 0); + assert_eq!(classes[1], 0); + assert_eq!(classes[2], 0); + assert_eq!(classes[3], 1); + assert_eq!(classes[4], 2); + assert_eq!(classes[5], 2); + assert_eq!(classes[6], 2); + assert_eq!(classes[7], 3); + assert_eq!(classes[255], 3); + } +} diff --git a/src/dfa.rs b/src/dfa.rs new file mode 100644 index 0000000000..981c654d16 --- /dev/null +++ b/src/dfa.rs @@ -0,0 +1,1164 @@ +// Copyright 2014-2016 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +/*! +The DFA matching engine. + +A DFA provides faster matching because the engine is in exactly one state at +any point in time. In the NFA, there may be multiple active states, and +considerable CPU cycles are spent shuffling them around. In finite automata +speak, the DFA follows epsilon transitions in the regex far less than the NFA. + +A DFA is a classic trade off between time and space. The NFA is slower, but +its memory requirements are typically small and predictable. The DFA is faster, +but given the right regex and the right input, the number of states in the +DFA can grow exponentially. To mitigate this space problem, we do two things: + +1. We implement an *online* DFA. That is, the DFA is constructed from the NFA + during a search. When a new state is computed, it is stored in a cache so + that it may be reused. An important consequence of this implementation + is that states that are never reached for a particular input are never + computed. (This is impossible in an "offline" DFA which needs to compute + all possible states up front.) +2. If the cache gets too big, we wipe it and continue matching. + +In pathological cases, a new state can be created for every byte of input. +(e.g., The regex `(a|b)*a(a|b){20}` on a long sequence of a's and b's.) +In this case, performance regresses to slightly slower than the full NFA +simulation, in large part because the cache becomes useless. (We could +investigate quitting the DFA and falling back to the NFA.) + +N.B. While this implementation is heavily commented, Russ Cox's series of +articles on regexes is strongly recommended: https://swtch.com/~rsc/regexp/ +(As is the DFA implementation in RE2, which heavily influenced this +implementation.) +*/ + +use std::collections::HashMap; +use std::fmt; +use std::mem; + +use inst::{Insts, Inst}; +use program::Program; +use sparse::SparseSet; + +/// The cache limit specifies approximately how much space we're willing to +/// give to the state cache. Once the state cache exceeds the size, it is wiped +/// and all states must be re-computed. +/// +/// Note that this value does not impact correctness. It can be set to 0 and +/// the DFA will run just fine. (It will only ever store exactly one state +/// in the cache, and will likely run very slowly, but it will work.) +/// +/// Also note that this limit is *per thread of execution*. That is, if the +/// same regex is used to search text across multiple threads simultaneously, +/// then the DFA cache is not shared. Instead, copies are made. +/// +/// TODO(burntsushi): This feels like a knob that a caller ought to be able to +/// configure. +const CACHE_LIMIT: usize = 2 * (1<<20); + +/// Return true if and only if the given program can be executed by a DFA. +/// +/// Generally, a DFA is possible only when there are no word boundary +/// assertions. This is due to the difficulty (but likely not impossibility) +/// of tracking multi-byte assertions in the DFA. +pub fn can_exec(insts: &Insts) -> bool { + use inst::EmptyLook::*; + // If for some reason we manage to allocate a regex program with more + // than 2^32-1 instructions, then we can't execute the DFA because we + // use 32 bit pointers. + if insts.len() > ::std::u32::MAX as usize { + return false; + } + for inst in insts { + match *inst { + Inst::Char(_) | Inst::Ranges(_) => return false, + Inst::EmptyLook(ref inst) => { + match inst.look { + WordBoundary | NotWordBoundary => return false, + StartLine | EndLine | StartText | EndText => {} + } + } + Inst::Match | Inst::Save(_) | Inst::Split(_) | Inst::Bytes(_) => {} + } + } + true +} + +/// The result of running the DFA. +/// +/// Conceptually, this is essentially equivalent to an `Option`, where +/// the value indicates where the end of a match was found, if any. We split +/// this out into a third state called EarlyMatch, which indicates both that +/// the caller specified that they didn't care about *where* a match was found, +/// and that the position at which the earliest match occurred may not be the +/// correct leftmost-first ending match position. +/// +/// NoMatch indicates that no match will ever be found and that processing can +/// quit immediately. +#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)] +pub enum DfaResult { + Match(usize), + EarlyMatch, + NoMatch, +} + +/// A reusable cache of DFA states. +/// +/// This cache is reused between multiple invocations of the same regex +/// program. (It is not shared simultaneously between threads. If there is +/// contention, then new caches are created.) +#[derive(Debug)] +pub struct DfaCache { + /// A cache of pre-compiled DFA states, keyed by the set of NFA states + /// and the set of empty-width flags set at the byte in the input when the + /// state was observed. + /// + /// A StatePtr is effectively a `*State`, but to avoid reference counting, + /// we just pass indexes around manually. The performance impact of this + /// isn't particularly clear, but this does enable us to use 32 bit + /// indexes, which can significantly impact the number of states we can + /// cram into our memory bounds. + compiled: HashMap, + /// Our heap of states. Both `DfaCache.compiled` and `State.next` point + /// into this vec. + states: Vec, + /// A set of cached start states, which are limited to the number of + /// permutations of flags set just before the initial byte of input. (The + /// index into this vec is a `Flags`.) + /// + /// N.B. A start state can be "dead" (i.e., no possible match), so we + /// represent it with a StatePtr. + start_states: Vec, + /// Stack scratch space used to follow epsilon transitions in the NFA. + /// (This permits us to avoid recursion.) + /// + /// The maximum stack size is the number of NFA states. + stack: Vec, + /// qcur and qnext are ordered sets with constant time + /// addition/membership/clearing-whole-set and linear time iteration. They + /// are used to manage the sets of NFA states in DFA states when computing + /// cached DFA states. In particular, the order of the NFA states matters + /// for leftmost-first style matching. Namely, when computing a cached + /// state, the set of NFA states stops growing as soon as the first Match + /// instruction is observed. + qcur: SparseSet, + qnext: SparseSet, +} + +/// Dfa encapsulates the actual execution of the DFA. +/// +/// Most of the fields in this struct are mutable pointers to locations in the +/// DFA cache. +/// +/// Why don't we just store the DfaCache directly in this struct? Well, it +/// turns out that we often want to "iterate over {qcur,qnext} and perform +/// some possibly mutable operation." The borrow checker forbids this, even +/// if the callee doesn't mutate {qcur,qnext}. Therefore, we stick most of +/// DfaCache into Dfa directly as pointers and pass {qcur,qnext} around as +/// parameters. +/// +/// N.B. We only use a single lifetime here since all pointers are taken +/// from the same cache. +#[derive(Debug)] +pub struct Dfa<'a> { + /// prog contains the NFA instruction opcodes. DFA execution uses either + /// the `dfa` instructions or the `dfa_reverse` instructions from + /// `exec::Executor`. (It never uses `Executor.prog`, which may have + /// Unicode opcodes that cannot be executed by this DFA.) + prog: &'a Program, + /// The start state. We record it here because the pointer may change + /// when the cache is wiped. + start: StatePtr, + /// When set, we can stop searching immediately after we enter a match + /// state. (Normally we keep searching in order to provide leftmost-first + /// semantics.) + quit_on_first_match: bool, + /// These are all from DfaCache. (Only {qcur,qnext} are missing.) + compiled: &'a mut HashMap, + states: &'a mut Vec, + start_states: &'a mut Vec, + stack: &'a mut Vec, +} + +/// State is a DFA state. It contains transitions to next states (given an +/// input byte), an ordered set of NFA states (not necessarily complete) and +/// the set of empty-width flags set in the input when this state was created. +/// (It also contains the set of empty-width flags in all of its constituent +/// NFA states, which is useful for determining where and when to try and +/// follow epsilon transitions.) +#[derive(Clone)] +struct State { + /// The set of transitions out of this state to other states. + /// + /// This is tricky and is NOT a simple vec with length 256. A vec with + /// length 256 would work fine if not for the following: + /// + /// 1. Empty assertions can lead to matches "at the boundary" of the input, + /// so it is useful to have one extra transition that corresponds to + /// EOF. So why doesn't a vec with length 257 work? + /// 2. If the vec has length 257 and each StatePtr is 4 bytes (even on 64 + /// bit), then every state occupies at least 1KB on the heap. That's + /// ridiculous. As an optimization, we compute the set of all + /// equivalence classes of bytes in the regex. Each equivalence class + /// is defined to be the set of bytes that are indistinguishable when + /// searching for a match. For example, in the regex `[a-z]`, the byte + /// ranges `0..ord(a)-1`, `ord(a)-ord(z)` and `ord(z)+1..257` all + /// correspond to distinct classes. Therefore, we only need a vec of + /// length *3* for that particular regex, which is quite a bit better. + /// (Equivalence classes are computed during compilation.) + next: Vec, + /// The set of NFA states in this DFA state, which are computed by + /// following epsilon transitions from `insts[0]`. Note that not all + /// epsilon transitions are necessarily followed! Namely, epsilon + /// transitions that correspond to empty assertions are only followed if + /// the flags set at the current byte satisfy the assertion. + insts: Vec, + /// Whether this is a match state or not. + is_match: bool, + /// The set of flags implied by the NFA states in `insts`. + /// + /// This never has the match flag set. + inst_flags: Flags, +} + +/// A state's key for identifying it in the cache. In particular, if two +/// state's cache keys are equivalent, then they cannot be discriminatory in +/// a match. +/// +/// We capture two bits of information: an ordered set of NFA states for the +/// DFA state and whether it corresponds to a match state. +#[derive(Clone, Debug, Eq, Hash, PartialEq)] +struct StateKey { + /// An ordered set of NFA states. + insts: Vec, + /// Whether this is a matching state or not. + is_match: bool, +} + +/// InstPtr is a 32 bit pointer into a sequence of opcodes (i.e., it indexes +/// an NFA state). +/// +/// Throughout this library, this is usually set to `usize`, but we force a +/// `u32` here to save on space. +type InstPtr = u32; + +/// StatePtr is a 32 bit pointer into a sequence of states. +/// +/// It has two special values: STATE_UNKNOWN and STATE_DEAD. All other values +/// are valid indexes into a cache's state sequence. +/// +/// (We use sentinel values here to save on space. A more sensible +/// representation is a sum type.) +type StatePtr = u32; + +/// An unknown state means that the state has not been computed yet, and that +/// the only way to progress is to compute it. +const STATE_UNKNOWN: StatePtr = 0; + +/// A dead state means that the state has been computed and it is known that +/// once it is entered, no match can ever occur. +const STATE_DEAD: StatePtr = 1; + +/// Byte is a u8 in spirit, but a u16 in practice so that we can represent the +/// special EOF sentinel value. +#[derive(Copy, Clone, Debug)] +struct Byte(u16); + +/// A set of flags. All flags correspond to empty assertions (either in the +/// input or in the opcodes) except for one: the match flag. +#[derive(Clone, Copy, Eq, Hash, PartialEq)] +struct Flags(u8); + +impl DfaCache { + /// Create new empty cache for the DFA engine. + pub fn new() -> Self { + DfaCache { + compiled: HashMap::new(), + states: vec![State::invalid(), State::invalid()], + start_states: vec![STATE_UNKNOWN; 256], + stack: vec![], + qcur: SparseSet::new(0), + qnext: SparseSet::new(0), + } + } + + /// Resizes ensures that the cache is the right size for the given program. + /// + /// N.B. This exists because it is inconvenient (i.e., my failing) to tie + /// the initial creation of the cache with knowledge about the program, so + /// we resize it once. + fn resize(&mut self, num_insts: usize) { + if num_insts == self.qcur.capacity() { + return; + } + self.qcur = SparseSet::new(num_insts); + self.qnext = SparseSet::new(num_insts); + } +} + +impl<'a> Dfa<'a> { + /// The main entry point to executing a DFA, which returns the *end* of + /// a match if one exists, using Perl's "leftmost-first" semantics. + /// + /// text can safely be arbitrary bytes, and the location returned is still + /// guaranteed to correspond to a valid UTF-8 sequence boundary. (Note + /// though that whether arbitrary bytes are actually consumed depends on + /// the given program.) + /// + /// at is the position in text at which to start looking for a match. While + /// it may seem like we should omit `at` and just rely on the caller to + /// slice `text` appropriately, it is necessary to tell whether `at` is + /// at the beginning of `text` or not (i.e., for empty assertions). + /// + /// quit_on_first_match should be set if the caller doesn't care about + /// where the match ends. If a match is found, DfaResult::EarlyMatch is + /// returned. + pub fn exec( + prog: &'a Program, + text: &[u8], + at: usize, + quit_on_first_match: bool, + ) -> DfaResult { + // Retrieve our DFA cache from the program. If another thread tries to + // execute this DFA *simultaneously*, then a new independent cache is + // created. + let mut _cache = prog.cache_dfa(); + let mut cache = &mut **_cache; + cache.resize(prog.insts.len()); + + let mut dfa = Dfa { + prog: prog, + compiled: &mut cache.compiled, + states: &mut cache.states, + start_states: &mut cache.start_states, + start: 0, // filled in below + stack: &mut cache.stack, + quit_on_first_match: quit_on_first_match, + }; + dfa.start = match dfa.start_state(&mut cache.qcur, text, at) { + STATE_DEAD => return DfaResult::NoMatch, + si => si, + }; + debug_assert!(dfa.start != STATE_UNKNOWN); + if prog.insts.is_reversed() { + dfa.exec_at_reverse(&mut cache.qcur, &mut cache.qnext, text, at) + } else { + dfa.exec_at(&mut cache.qcur, &mut cache.qnext, text, at) + } + } + + /// Executes the DFA on a forward NFA. + /// + /// {qcur,qnext} are scratch ordered sets which may be non-empty. + fn exec_at( + &mut self, + qcur: &mut SparseSet, + qnext: &mut SparseSet, + text: &[u8], + at: usize, + ) -> DfaResult { + // For the most part, the DFA is basically: + // + // last_match = null + // while current_byte != EOF: + // si = current_state.next[current_byte] + // if si is match + // last_match = si + // return last_match + // + // However, we need to deal with a few things: + // + // 1. This is an *online* DFA, so the current state's next list + // may not point to anywhere yet, so we must go out and compute + // them. (They are then cached into the current state's next list + // to avoid re-computation.) + // 2. If we come across a state that is known to be dead (i.e., never + // leads to a match), then we can quit early. + // 3. If the caller just wants to know if a match occurs, then we + // can quit as soon as we know we have a match. (Full leftmost + // first semantics require continuing on.) + // 4. If we're in the start state, then we can use a pre-computed set + // of prefix literals to skip quickly along the input. + // 5. After the input is exhausted, we run the DFA on one symbol + // that stands for EOF. This is useful for handling empty width + // assertions. + // 6. We can't actually do state.next[byte]. Instead, we have to do + // state.next[byte_classes[byte]], which permits us to keep the + // 'next' list very small. + debug_assert!(!self.prog.is_reversed()); + + // last_match is the currently known ending match position. It is + // reported as an index to the most recent byte that resulted in a + // transition to a match state. Its maximum value is `text.len()`, + // which can only happen after the special EOF sentinel value is fed + // to the DFA. + let mut last_match = DfaResult::NoMatch; + let (mut si, mut i) = (self.start, at); + while i < text.len() { + // Our set of literal prefixes can itself be a DFA, but it is + // offline and can generally be quite a bit faster. (For instance, + // memchr is used if possible.) + if !self.prog.prefixes.is_empty() && si == self.start { + i = match self.prefix_at(text, i) { + None => return DfaResult::NoMatch, + Some(i) => i, + }; + } + + // The following logic is essentially what `self.next_state` does, + // but we inline it manually here to avoid the extra branch and + // also because we know we have a real `u8` (not a `Byte`, which + // may be the special EOF sentinel value). + let cls = self.prog.insts.byte_classes()[text[i] as usize]; + let mut next_si = self.states[si as usize].next[cls]; + if next_si <= STATE_DEAD { + if next_si == STATE_DEAD { + return last_match; + } + // The next state may not have been cached, so re-compute it + // (i.e., follow epsilon transitions). + next_si = self.exec_byte(qcur, qnext, si, Byte::byte(text[i])); + debug_assert!(next_si != STATE_UNKNOWN); + if next_si == STATE_DEAD { + return last_match; + } + } + si = next_si; + if self.states[si as usize].is_match { + if self.quit_on_first_match { + return DfaResult::EarlyMatch; + } + last_match = DfaResult::Match(i); + } + i += 1; + } + // Run the DFA once more on the special EOF senitnel value. + si = self.next_state(qcur, qnext, si, Byte::eof()); + debug_assert!(si != STATE_UNKNOWN); + if si == STATE_DEAD { + return last_match; + } + if self.states[si as usize].is_match { + last_match = DfaResult::Match(text.len()); + } + last_match + } + + /// Executes the DFA on a reverse NFA. + fn exec_at_reverse( + &mut self, + qcur: &mut SparseSet, + qnext: &mut SparseSet, + text: &[u8], + at: usize, + ) -> DfaResult { + // The comments in `exec_at` above mostly apply here too. The main + // difference is that we move backwards over the input and we look for + // the longest possible match instead of the leftmost-first match. + // + // N.B. The code duplication here is regrettable. Efforts to improve + // it without sacrificing performance are welcome. ---AG + debug_assert!(self.prog.is_reversed()); + let mut last_match = DfaResult::NoMatch; + let (mut si, mut i) = (self.start, at); + while i > 0 { + i -= 1; + + let cls = self.prog.insts.byte_classes()[text[i] as usize]; + let mut next_si = self.states[si as usize].next[cls]; + if next_si <= STATE_DEAD { + if next_si == STATE_DEAD { + return last_match; + } + // The next state may not have been cached, so re-compute it + // (i.e., follow epsilon transitions). + next_si = self.exec_byte(qcur, qnext, si, Byte::byte(text[i])); + debug_assert!(next_si != STATE_UNKNOWN); + if next_si == STATE_DEAD { + return last_match; + } + } + si = next_si; + if self.states[si as usize].is_match { + if self.quit_on_first_match { + return DfaResult::EarlyMatch; + } + last_match = DfaResult::Match(i+1); + } + } + si = self.next_state(qcur, qnext, si, Byte::eof()); + debug_assert!(si != STATE_UNKNOWN); + if si == STATE_DEAD { + return last_match; + } + if self.states[si as usize].is_match { + last_match = DfaResult::Match(0); + } + last_match + } + + /// Computes the next state given the current state and the current input + /// byte (which may be EOF). + /// + /// If STATE_DEAD is returned, then there is no valid state transition. + /// This implies that no permutation of future input can lead to a match + /// state. + /// + /// STATE_UNKNOWN can never be returned. + fn exec_byte( + &mut self, + qcur: &mut SparseSet, + qnext: &mut SparseSet, + mut si: StatePtr, + b: Byte, + ) -> StatePtr { + use inst::Inst::*; + + // Initialize a queue with the current DFA state's NFA states. + qcur.clear(); + for &ip in &self.states[si as usize].insts { + qcur.add(ip as usize); + } + + // Before inspecting the current byte, we may need to also inspect + // whether the position immediately preceding the current byte + // satisfies the empty assertions found in the current state. + // + // We only need to do this step if there are any empty assertions in + // the current state. + if self.states[si as usize].inst_flags.has_non_match_flags() { + // Compute the flags immediately preceding the current byte. + // This means we only care about the "end" or "end line" flags. + // (The "start" flags are computed immediately proceding the + // current byte and is handled below.) + let mut flags = Flags::new(); + if b.is_eof() { + flags.set_end(true).set_end_line(true); + } else if b.as_byte().map_or(false, |b| b == b'\n') { + flags.set_end_line(true); + } + // Now follow epsilon transitions from every NFA state, but make + // sure we only follow transitions that satisfy our flags. + qnext.clear(); + for &ip in &*qcur { + self.follow_epsilons(usize_to_u32(ip), qnext, flags); + } + mem::swap(qcur, qnext); + } + + // Now we set flags for immediately after the current byte. Since start + // states are processed separately, and are the only states that can + // have the StartText flag set, we therefore only need to worry about + // the StartLine flag here. + // + // We do also keep track of whether this DFA state contains a NFA state + // that is a matching state. This is precisely how we delay the DFA + // matching by one byte in order to process the special EOF sentinel + // byte. Namely, if this DFA state containing a matching NFA state, + // then it is the *next* DFA state that is marked as a match. + let mut flags = Flags::new(); + if b.as_byte().map_or(false, |b| b == b'\n') { + flags.set_start_line(true); + } + // Now follow all epsilon transitions again, but only after consuming + // the current byte. + qnext.clear(); + for &ip in &*qcur { + match self.prog.insts[ip as usize] { + // These states never happen in a byte-based program. + Char(_) | Ranges(_) => unreachable!(), + // These states are handled when following epsilon transitions. + Save(_) | Split(_) | EmptyLook(_) => {} + Match => { + flags.set_match(true); + if !self.prog.is_reversed() { + break; + } + } + Bytes(ref inst) => { + if b.as_byte().map_or(false, |b| inst.matches(b)) { + self.follow_epsilons( + inst.goto as InstPtr, qnext, flags); + } + } + } + } + // We've now built up the set of NFA states that ought to comprise the + // next DFA state, so try to find it in the cache, and if it doesn't + // exist, cache it. + // + // N.B. We pass `&mut si` here because the cache may clear itself if + // it has gotten too full. When that happens, the location of the + // current state may change. + let next = self.cached_state(qnext, flags.is_match(), Some(&mut si)); + debug_assert!(next != STATE_UNKNOWN); + // And now store our state in the current state's next list. + let cls = self.byte_class(b); + self.states[si as usize].next[cls] = next; + next + } + + /// Follows the epsilon transitions starting at (and including) `ip`. The + /// resulting states are inserted into the ordered set `q`. + /// + /// Conditional epsilon transitions (i.e., empty width assertions) are only + /// followed if they are satisfied by the given flags, which should + /// represent the flags set at the current location in the input. + /// + /// If the current location corresponds to the empty string, then only the + /// end line and/or end text flags may be set. If the current location + /// corresponds to a real byte in the input, then only the start line + /// and/or start text flags may be set. + /// + /// As an exception to the above, when finding the initial state, any of + /// the above flags may be set: + /// + /// If matching starts at the beginning of the input, then start text and + /// start line should be set. If the input is empty, then end text and end + /// line should also be set. + /// + /// If matching starts after the beginning of the input, then only start + /// line should be set if the preceding byte is `\n`. End line should never + /// be set in this case. (Even if the proceding byte is a `\n`, it will + /// be handled in a subsequent DFA state.) + fn follow_epsilons( + &mut self, + ip: InstPtr, + q: &mut SparseSet, + flags: Flags, + ) { + use inst::Inst::*; + use inst::EmptyLook::*; + + // We need to traverse the NFA to follow epsilon transitions, so avoid + // recursion with an explicit stack. + self.stack.push(ip); + while let Some(ip) = self.stack.pop() { + // Don't visit states we've already added. + if q.contains_ip(ip as usize) { + continue; + } + q.add(ip as usize); + match self.prog.insts[ip as usize] { + Char(_) | Ranges(_) => unreachable!(), + Match | Bytes(_) => {} + EmptyLook(ref inst) => { + // Only follow empty assertion states if our flags satisfy + // the assertion. + match inst.look { + StartLine if flags.is_start_line() => { + self.stack.push(inst.goto as InstPtr); + } + EndLine if flags.is_end_line() => { + self.stack.push(inst.goto as InstPtr); + } + StartText if flags.is_start() => { + self.stack.push(inst.goto as InstPtr); + } + EndText if flags.is_end() => { + self.stack.push(inst.goto as InstPtr); + } + StartLine | EndLine | StartText | EndText => {} + // The DFA doesn't support word boundaries. :-( + WordBoundary | NotWordBoundary => unreachable!(), + } + } + Save(ref inst) => self.stack.push(inst.goto as InstPtr), + Split(ref inst) => { + self.stack.push(inst.goto2 as InstPtr); + self.stack.push(inst.goto1 as InstPtr); + } + } + } + } + + /// Find a previously computed state matching the given set of instructions + /// and is_match bool. + /// + /// The given set of instructions should represent a single state in the + /// NFA along with all states reachable without consuming any input. + /// + /// The is_match bool should be true if and only if the preceding DFA state + /// contains an NFA matching state. The cached state produced here will + /// then signify a match. (This enables us to delay a match by one byte, + /// in order to account for the EOF sentinel byte.) + /// + /// If the cache is full, then it is wiped before caching a new state. + /// + /// The current state should be specified if it exists, since it will need + /// to be preserved if the cache clears itself. (Start states are + /// always saved, so they should not be passed here.) It takes a mutable + /// pointer to the index because if the cache is cleared, the state's + /// location may change. + fn cached_state( + &mut self, + q: &SparseSet, + is_match: bool, + current_state: Option<&mut StatePtr>, + ) -> StatePtr { + // If we couldn't come up with a non-empty key to represent this state, + // then it is dead and can never lead to a match. + // + // Note that inst_flags represent the set of empty width assertions + // in q. We use this as an optimization in exec_byte to determine when + // we should follow epsilon transitions at the empty string preceding + // the current byte. + let (key, inst_flags) = match self.cached_state_key(q, is_match) { + None => return STATE_DEAD, + Some(v) => v, + }; + // In the cache? Cool. Done. + if let Some(&si) = self.compiled.get(&key) { + return si; + } + + // If the cache has gotten too big, wipe it. + if self.approximate_size() > CACHE_LIMIT { + self.clear_cache_and_save(current_state); + } + + // OK, now there's enough room to push our new state. + // We do this even if the cache size is set to 0! + let next = vec![STATE_UNKNOWN; self.num_byte_classes()]; + self.states.push(State { + next: next, + insts: key.insts.clone(), + is_match: is_match, + inst_flags: inst_flags, + }); + let si = usize_to_u32(self.states.len().checked_sub(1).unwrap()); + self.compiled.insert(key, si); + si + } + + /// Produces a key suitable for describing a state in the DFA cache. + /// + /// The key invariant here is that equivalent keys are produced for any two + /// sets of ordered NFA states (and toggling of whether the previous NFA + /// states contain a match state) that do not discriminate a match for any + /// input. + /// + /// Specifically, q should be an ordered set of NFA states and is_match + /// should be true if and only if the previous NFA states contained a match + /// state. + fn cached_state_key( + &mut self, + q: &SparseSet, + is_match: bool, + ) -> Option<(StateKey, Flags)> { + use inst::Inst::*; + use inst::EmptyLook::*; + + // We need to build up enough information to recognize pre-built states + // in the DFA. Generally speaking, this includes every instruction + // except for those which are purely epsilon transitions, e.g., the + // Save and Split instructions. + // + // Empty width assertions are also epsilon transitions, but since they + // are conditional, we need to make them part of a state's key in the + // cache. + let mut inst_flags = Flags::new(); + let mut insts = vec![]; + for &ip in q { + let ip = usize_to_u32(ip); + match self.prog.insts[ip as usize] { + Char(_) | Ranges(_) => unreachable!(), + Save(_) => {} + Split(_) => {} + Bytes(_) => insts.push(ip), + EmptyLook(ref inst) => { + match inst.look { + StartLine => { + inst_flags.set_start_line(true); + insts.push(ip); + } + EndLine => { + inst_flags.set_end_line(true); + insts.push(ip); + } + StartText => { + inst_flags.set_start(true); + insts.push(ip); + } + EndText => { + inst_flags.set_end(true); + insts.push(ip); + } + WordBoundary | NotWordBoundary => unreachable!(), + } + } + Match => { + insts.push(ip); + // If this is a reverse program, then we want to continue + // executing to find the longest possible match. Otherwise, + // we only support leftmost-first semantics, so bail out. + if !self.prog.insts.is_reversed() { + break; + } + } + } + } + // If we couldn't transition to any other instructions and we didn't + // see a match when expanding NFA states previously, then this is a + // dead state and no amount of additional input can transition out + // of this state. + if insts.len() == 0 && !is_match { + None + } else { + let key = StateKey { insts: insts, is_match: is_match }; + Some((key, inst_flags)) + } + } + + /// Clears the cache, but saves and restores current_state if it is not + /// none. + /// + /// The current state must be provided here in case its location in the + /// cache changes. + fn clear_cache_and_save(&mut self, current_state: Option<&mut StatePtr>) { + if self.states.len() <= 2 { + // Why <= 2? Well, the states list always has its first two + // positions filled by marker states for STATE_UNKNOWN and + // STATE_DEAD. These states aren't actually used, but exist to + // make sure no other state lives in those locations. Therefore, + // a state vec with length <= 2 is actually "empty." + return; + } + match current_state { + None => self.clear_cache(), + Some(si) => { + let cur = self.copy_state(*si); + self.clear_cache(); + *si = self.restore_state(cur); + } + } + } + + /// Wipes the state cache, but saves and restores the current start state. + fn clear_cache(&mut self) { + let start = self.copy_state(self.start); + self.states.clear(); + self.compiled.clear(); + for start in self.start_states.iter_mut() { + *start = STATE_UNKNOWN; + } + self.states.push(State::invalid()); + self.states.push(State::invalid()); + self.start = self.restore_state(start); + } + + /// Returns a fresh copy of state si with all of its next pointers set to + /// unknown. + fn copy_state(&self, si: StatePtr) -> State { + let mut state = self.states[si as usize].clone(); + // Make sure to erase any pointers from this state, so that + // they are forced to be re-computed. + state.next = vec![STATE_UNKNOWN; self.num_byte_classes()]; + state + } + + /// Restores the given state back into the cache, and returns a pointer + /// to it. + fn restore_state(&mut self, state: State) -> StatePtr { + let key = StateKey { + insts: state.insts.clone(), + is_match: state.is_match, + }; + if let Some(&si) = self.compiled.get(&key) { + return si; + } + let si = usize_to_u32(self.states.len()); + self.states.push(state); + self.compiled.insert(key, si); + si + } + + /// Returns the next state given the current state si and current byte + /// b. {qcur,qnext} are used as scratch space for storing ordered NFA + /// states. + /// + /// This tries to fetch the next state from the cache, but if that fails, + /// it computes the next state, caches it and returns a pointer to it. + /// + /// The pointer can be to a real state, or it can be STATE_DEAD. + /// STATE_UNKNOWN cannot be returned. + fn next_state( + &mut self, + qcur: &mut SparseSet, + qnext: &mut SparseSet, + si: StatePtr, + b: Byte, + ) -> StatePtr { + let cls = self.byte_class(b); + match self.states[si as usize].next[cls] { + STATE_UNKNOWN => self.exec_byte(qcur, qnext, si, b), + STATE_DEAD => return STATE_DEAD, + nsi => return nsi, + } + } + + /// Computes and returns the start state, where searching begins at + /// position `at` in `text`. If the state has already been computed, + /// then it is pulled from the cache. If the state hasn't been cached, + /// then it is computed, cached and a pointer to it is returned. + /// + /// This may return STATE_DEAD but never STATE_UNKNOWN. + fn start_state( + &mut self, + q: &mut SparseSet, + text: &[u8], + at: usize, + ) -> StatePtr { + let start_flags = if self.prog.insts.is_reversed() { + self.start_flags_reverse(text, at) + } else { + self.start_flags(text, at) + }; + let flagi = start_flags.0 as usize; + match self.start_states[flagi] { + STATE_UNKNOWN => {} + STATE_DEAD => return STATE_DEAD, + si => return si, + } + q.clear(); + self.follow_epsilons(0, q, start_flags); + // Start states can never be match states because we delay every match + // by one byte. Given an empty string and an empty match, the match + // won't actually occur until the DFA processes the special EOF + // sentinel byte. + let sp = self.cached_state(q, false, None); + self.start_states[flagi] = sp; + sp + } + + /// Computes the set of starting flags for the given position in text. + /// + /// This should only be used when executing the DFA forwards over the + /// input. + fn start_flags(&self, text: &[u8], at: usize) -> Flags { + let mut flags = Flags::new(); + flags.set_start(at == 0).set_end(text.len() == 0); + flags.set_start_line(at == 0 || text[at - 1] == b'\n'); + flags.set_end_line(text.len() == 0); + flags + } + + /// Computes the set of starting flags for the given position in text. + /// + /// This should only be used when executing the DFA in reverse over the + /// input. + fn start_flags_reverse(&self, text: &[u8], at: usize) -> Flags { + let mut flags = Flags::new(); + flags.set_start(at == text.len()).set_end(text.len() == 0); + flags.set_start_line(at == text.len() || text[at] == b'\n'); + flags.set_end_line(text.len() == 0); + flags + } + + /// Quickly finds the next occurrence of any literal prefixes in the regex. + /// If there are no literal prefixes, then the current position is + /// returned. If there are literal prefixes and one could not be found, + /// then None is returned. + /// + /// This should only be called when the DFA is in a start state. + fn prefix_at(&self, text: &[u8], at: usize) -> Option { + self.prog.prefixes.find(&text[at..]).map(|(s, _)| at + s) + } + + /// Returns the number of byte classes required to discriminate transitions + /// in each state. + /// + /// invariant: num_byte_classes() == len(State.next) + fn num_byte_classes(&self) -> usize { + // We add 1 to account for the special EOF byte. + (self.prog.insts.byte_classes()[255] + 1) + 1 + } + + /// Given an input byte or the special EOF sentinel, return its + /// corresponding byte class. + fn byte_class(&self, b: Byte) -> usize { + if b.is_eof() { + self.num_byte_classes() - 1 + } else { + self.prog.insts.byte_classes()[b.0 as usize] + } + } + + /// Approximate size returns the approximate heap space currently used by + /// the DFA. It is used to determine whether the DFA's state cache needs to + /// be wiped. Namely, it is possible that for certain regexes on certain + /// inputs, a new state could be created for every byte of input. (This is + /// bad for memory use, so we bound it with a cache.) + /// + /// The approximation is guaranteed to be done in constant time (and + /// indeed, this requirement is why it's approximate). + fn approximate_size(&self) -> usize { + use std::mem::size_of as size; + // Estimate that there are about 32 instructions per state consuming + // 128 = 32 * 4 bytes of space. (This is hopefully a blatant + // overestimate.) + let compiled = + (self.compiled.len() * (size::() + 128)) + + (self.compiled.len() * size::()); + let states = + self.states.len() + * (size::() + + 128 + + (self.num_byte_classes() * size::())); + let start_states = self.start_states.len() * size::(); + self.prog.approximate_size() + compiled + states + start_states + } +} + +impl State { + /// Return an invalid state. This is only used to "pad" the state cache so + /// that the special sentinel values (STATE_UNKNOWN and STATE_DEAD) are + /// never used. + fn invalid() -> State { + State { + next: vec![], + insts: vec![], + is_match: false, + inst_flags: Flags::new(), + } + } +} + +impl Flags { + #[inline] + fn new() -> Self { + Flags(0) + } + + #[inline] + fn has_non_match_flags(&self) -> bool { + self.0 & 0b0_1111111 > 0 + } + + #[inline] + fn set(&mut self, yes: bool, bit: u8) { + if yes { + self.0 = self.0 | bit; + } else { + self.0 = self.0 & !bit; + } + } + + #[inline] + fn is_match(&self) -> bool { self.0 & 0b1_0000000 > 0 } + + #[inline] + fn set_match(&mut self, yes: bool) -> &mut Self { + self.set(yes, 0b1_0000000); + self + } + + #[inline] + fn is_start(&self) -> bool { self.0 & 0b0_1_000000 > 0 } + + #[inline] + fn set_start(&mut self, yes: bool) -> &mut Self { + self.set(yes, 0b0_1_000000); + self + } + + #[inline] + fn is_end(&self) -> bool { self.0 & 0b00_1_00000 > 0 } + + #[inline] + fn set_end(&mut self, yes: bool) -> &mut Self { + self.set(yes, 0b00_1_00000); + self + } + + #[inline] + fn is_start_line(&self) -> bool { self.0 & 0b000_1_0000 > 0 } + + #[inline] + fn set_start_line(&mut self, yes: bool) -> &mut Self { + self.set(yes, 0b000_1_0000); + self + } + + #[inline] + fn is_end_line(&self) -> bool { self.0 & 0b0000_1_000 > 0 } + + #[inline] + fn set_end_line(&mut self, yes: bool) -> &mut Self { + self.set(yes, 0b0000_1_000); + self + } +} + +impl Byte { + #[inline] fn byte(b: u8) -> Self { Byte(b as u16) } + #[inline] fn eof() -> Self { Byte(256) } + #[inline] fn is_eof(&self) -> bool { self.0 == 256 } + + #[inline] + fn as_byte(&self) -> Option { + if self.is_eof() { + None + } else { + Some(self.0 as u8) + } + } +} + +impl fmt::Debug for State { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + let mut next = vec![]; + for (b, next_sp) in self.next.iter().enumerate() { + match *next_sp { + STATE_UNKNOWN => {} + STATE_DEAD => next.push((vb(b as usize), "DEAD".to_string())), + si => next.push((vb(b as usize), si.to_string())), + } + } + f.debug_struct("State") + .field("is_match", &self.is_match) + .field("insts", &self.insts) + .field("next", &next) + .finish() + } +} + +impl fmt::Debug for Flags { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + f.debug_struct("Flags") + .field("match", &if self.is_match() { 1 } else { 0 }) + .field("start", &if self.is_start() { 1 } else { 0 }) + .field("end", &if self.is_end() { 1 } else { 0 }) + .field("start_line", &if self.is_start_line() { 1 } else { 0 }) + .field("end_line", &if self.is_end_line() { 1 } else { 0 }) + .finish() + } +} + +/// Helper function for formatting a byte as a nice-to-read escaped string. +fn vb(b: usize) -> String { + use std::ascii::escape_default; + + if b > ::std::u8::MAX as usize { + "EOF".to_owned() + } else { + let escaped = escape_default(b as u8).collect::>(); + String::from_utf8_lossy(&escaped).into_owned() + } +} + +fn usize_to_u32(n: usize) -> u32 { + if (n as u64) > (::std::u32::MAX as u64) { + panic!("BUG: {} is too big to fit into u32", n) + } + n as u32 +} diff --git a/src/exec.rs b/src/exec.rs new file mode 100644 index 0000000000..d68c14ec1c --- /dev/null +++ b/src/exec.rs @@ -0,0 +1,407 @@ +// Copyright 2014-2015 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +use backtrack::{self, Backtrack}; +use dfa::{self, Dfa, DfaResult}; +use input::{ByteInput, CharInput}; +use nfa::Nfa; +use program::{Program, ProgramBuilder}; +use re::CaptureIdxs; + +use {Regex, Error}; + +/// Exec manages the execution of a regular expression. +/// +/// In particular, this manages the various compiled forms of a single regular +/// expression and the choice of which matching engine to use to execute a +/// regular expression. +#[derive(Clone, Debug)] +pub struct Exec { + /// A compiled program that is used in the NFA simulation and backtracking. + /// It can be byte-based or Unicode codepoint based. + /// + /// N.B. It is not possibly to make this byte-based from the public API. + /// It is only used for testing byte based programs in the NFA simulations. + prog: Program, + /// A compiled byte based program for DFA execution. This is only used + /// if a DFA can be executed. (Currently, only word boundary assertions are + /// not supported.) Note that this program contains an embedded `.*?` + /// preceding the first capture group, unless the regex is anchored at the + /// beginning. + dfa: Program, + /// The same as above, except the program is reversed (and there is no + /// preceding `.*?`). This is used by the DFA to find the starting location + /// of matches. + dfa_reverse: Program, + /// Set to true if and only if the DFA can be executed. + can_dfa: bool, + /// A preference for matching engine selection. + /// + /// This defaults to Automatic, which means the matching engine is selected + /// based on heuristics (such as the nature and size of the compiled + /// program, in addition to the size of the search text). + /// + /// If either Nfa or Backtrack is set, then it is always used because + /// either is capable of executing every compiled program on any input + /// size. + match_engine: MatchEngine, +} + +/// Facilitates the construction of an executor by exposing various knobs +/// to control how a regex is executed and what kinds of resources it's +/// permitted to use. +pub struct ExecBuilder<'r> { + re: &'r str, + match_engine: MatchEngine, + size_limit: usize, + bytes: bool, +} + +impl<'r> ExecBuilder<'r> { + /// Create a regex execution builder. + /// + /// This uses default settings for everything except the regex itself, + /// which must be provided. Further knobs can be set by calling methods, + /// and then finally, `build` to actually create the executor. + pub fn new(re: &'r str) -> Self { + ExecBuilder { + re: re, + match_engine: MatchEngine::Automatic, + size_limit: 10 * (1 << 20), + bytes: false, + } + } + + /// Set the matching engine to be automatically determined. + /// + /// This is the default state and will apply whatever optimizations are + /// possible, such as running a DFA. + /// + /// This overrides whatever was previously set via the `nfa` or + /// `bounded_backtracking` methods. + pub fn automatic(mut self) -> Self { + self.match_engine = MatchEngine::Automatic; + self + } + + /// Sets the matching engine to use the NFA algorithm no matter what + /// optimizations are possible. + /// + /// This overrides whatever was previously set via the `automatic` or + /// `bounded_backtracking` methods. + pub fn nfa(mut self) -> Self { + self.match_engine = MatchEngine::Nfa; + self + } + + /// Sets the matching engine to use a bounded backtracking engine no + /// matter what optimizations are possible. + /// + /// One must use this with care, since the bounded backtracking engine + /// uses memory proportion to `len(regex) * len(text)`. + /// + /// This overrides whatever was previously set via the `automatic` or + /// `nfa` methods. + pub fn bounded_backtracking(mut self) -> Self { + self.match_engine = MatchEngine::Backtrack; + self + } + + /// Sets the size limit on a single compiled regular expression program. + /// + /// The default is ~10MB. + /// + /// N.B. Typically, multiple programs are compiled for every regular + /// expression and this limit applies to *each* of them. + pub fn size_limit(mut self, bytes: usize) -> Self { + self.size_limit = bytes; + self + } + + /// Compiles byte based programs for use with the NFA matching engines. + /// + /// By default, the NFA engines match on Unicode scalar values. They can + /// be made to use byte based programs instead. In general, the byte based + /// programs are slower because of a less efficient encoding of character + /// classes. However, it may be useful (some day) for matching on raw + /// bytes that may not be UTF-8. + /// + /// Note that this does not impact DFA matching engines, which always + /// execute on bytes. + pub fn bytes(mut self, yes: bool) -> Self { + self.bytes = yes; + self + } + + /// Build an executor that can run a regular expression. + pub fn build(self) -> Result { + let prog = try!( + ProgramBuilder::new(self.re) + .size_limit(self.size_limit) + .bytes(self.bytes) + .compile()); + let mut dfa = try!( + ProgramBuilder::new(self.re) + .size_limit(self.size_limit) + .dfa(true) + .compile()); + // Because the literal finder on byte-based programs is sub-optimal. + // We can use the literals found from a Unicode-based program just + // fine for now. + dfa.prefixes = prog.prefixes.clone(); + let dfa_reverse = try!( + ProgramBuilder::new(self.re) + .size_limit(self.size_limit) + .dfa(true) + .reverse(true) + .compile()); + let can_dfa = dfa::can_exec(&dfa.insts); + Ok(Exec { + prog: prog, + dfa: dfa, + dfa_reverse: dfa_reverse, + can_dfa: can_dfa, + match_engine: self.match_engine, + }) + } +} + +impl Exec { + /// The main entry point for execution of a regular expression on text. + /// + /// caps represents the capture locations that the caller wants. Generally, + /// there are three varieties: no captures requested (e.g., `is_match`), + /// one capture requested (e.g., `find` or `find_iter`) or multiple + /// captures requested (e.g., `captures` or `captures_iter` along with + /// at least one capturing group in the regex). Each of these three cases + /// provokes different behavior from the matching engines, where fewer + /// captures generally means faster matching. + /// + /// text should be the search text and start should be the position in + /// the text to start searching. Note that passing a simple slice here + /// isn't sufficient, since look-behind assertions sometimes need to + /// inspect the character immediately preceding the start location. + /// + /// Note that this method takes self.match_engine into account when + /// choosing the engine to use. If self.match_engine is Nfa or Backtrack, + /// then that engine is always used. Otherwise, one is selected + /// automatically. + pub fn exec( + &self, + caps: &mut CaptureIdxs, + text: &str, + start: usize, + ) -> bool { + // Why isn't the DFA or literal engine checked for here? Well, it's + // only possible to execute those engines in exec_auto. See comment on + // MatchEngine below for more details. + match self.match_engine { + MatchEngine::Automatic => self.exec_auto(caps, text, start), + MatchEngine::Backtrack => self.exec_backtrack(caps, text, start), + MatchEngine::Nfa => self.exec_nfa(caps, text, start), + } + } + + /// Like exec, but always selects the engine automatically. + pub fn exec_auto( + &self, + caps: &mut CaptureIdxs, + text: &str, + start: usize, + ) -> bool { + if caps.len() <= 2 && self.prog.is_prefix_match() { + // We should be able to execute the literal engine even if there + // are more captures by falling back to the NFA engine after a + // match. However, that's effectively what the NFA engine does + // already (since it will use the literal engine if it exists). + self.exec_literals(caps, text, start) + } else if self.can_dfa { + self.exec_dfa(caps, text, start) + } else { + self.exec_auto_nfa(caps, text, start) + } + } + + /// Like exec, but always tries to execute the lazy DFA. + /// + /// Note that self.can_dfa must be true. This will panic otherwise. + fn exec_dfa( + &self, + caps: &mut CaptureIdxs, + text: &str, + start: usize, + ) -> bool { + debug_assert!(self.can_dfa); + let btext = text.as_bytes(); + let search = Dfa::exec(&self.dfa, btext, start, caps.is_empty()); + let match_end = match search { + DfaResult::Match(match_end) => match_end, + DfaResult::EarlyMatch => return true, + DfaResult::NoMatch => return false, + }; + // If caller has not requested any captures, then we don't need to + // find the start position. + if caps.is_empty() { + return true; + } + // invariant: caps.len() >= 2 && caps.len() % 2 == 0 + // If the reported end of the match is the same as the start, then we + // have an empty match and we can quit now. + if start == match_end { + // Be careful... If the caller wants sub-captures, than we are + // obliged to run the NFA to get them. + if caps.len() == 2 { + // The caller only needs the start/end, so we can avoid the + // NFA here. + caps[0] = Some(start); + caps[1] = Some(start); + return true; + } + return self.exec_auto_nfa(caps, text, start); + } + // OK, now we find the start of the match by running the DFA backwards + // on the text. We *start* the search at the end of the match. + let search = Dfa::exec( + &self.dfa_reverse, &btext[start..], match_end - start, false); + let match_start = match search { + DfaResult::Match(match_start) => start + match_start, + DfaResult::EarlyMatch => { + panic!("BUG: early matches can't happen on reverse search") + } + DfaResult::NoMatch => { + panic!("BUG: forward match implies backward match") + } + }; + if caps.len() == 2 { + // If the caller doesn't care about capture locations, then we can + // avoid running the NFA to fill them in. + caps[0] = Some(match_start); + caps[1] = Some(match_end); + return true; + } + self.exec_auto_nfa(caps, text, match_start) + } + + /// This is like exec_auto, except it always chooses between either the + /// full NFA simulation or the bounded backtracking engine. + fn exec_auto_nfa( + &self, + caps: &mut CaptureIdxs, + text: &str, + start: usize, + ) -> bool { + if backtrack::should_exec(self.prog.insts.len(), text.len()) { + self.exec_backtrack(caps, text, start) + } else { + self.exec_nfa(caps, text, start) + } + } + + /// Always run the NFA algorithm. + fn exec_nfa( + &self, + caps: &mut CaptureIdxs, + text: &str, + start: usize, + ) -> bool { + if self.prog.insts.is_bytes() { + Nfa::exec(&self.prog, caps, ByteInput::new(text), start) + } else { + Nfa::exec(&self.prog, caps, CharInput::new(text), start) + } + } + + /// Always runs the NFA using bounded backtracking. + fn exec_backtrack( + &self, + caps: &mut CaptureIdxs, + text: &str, + start: usize, + ) -> bool { + if self.prog.insts.is_bytes() { + Backtrack::exec(&self.prog, caps, ByteInput::new(text), start) + } else { + Backtrack::exec(&self.prog, caps, CharInput::new(text), start) + } + } + + /// Executes the special literal matching engine. + /// + /// When a regular expression is small and can be expanded to a finite set + /// of literals that all result in matches, then we can avoid all of the + /// regex machinery and use specialized DFAs. + /// + /// This panics if the set of literals do not correspond to matches. + fn exec_literals( + &self, + caps: &mut CaptureIdxs, + text: &str, + start: usize, + ) -> bool { + debug_assert!(self.prog.is_prefix_match()); + match self.prog.prefixes.find(&text.as_bytes()[start..]) { + None => false, + Some((s, e)) => { + if caps.len() == 2 { + caps[0] = Some(start + s); + caps[1] = Some(start + e); + } + true + } + } + } + + /// Build a dynamic Regex from this executor. + pub fn into_regex(self) -> Regex { + Regex::Dynamic(self) + } + + /// Return the original regular expression string. + pub fn regex_str(&self) -> &str { + &self.prog.original + } + + /// Return a slice of capture names. + /// + /// Any capture that isn't named is None. + pub fn capture_names(&self) -> &[Option] { + &self.prog.cap_names + } + + /// Return a fresh allocation for storing all possible captures in the + /// underlying regular expression. + pub fn alloc_captures(&self) -> Vec> { + self.prog.alloc_captures() + } +} + +/// Some of the matching engines offered by this regex implementation. +/// +/// This is exported for use in testing. +/// +/// Note that only engines that can be used on *every* regex are exposed here. +/// For example, it is useful for testing purposes to say, "always execute +/// the backtracking engine" or "always execute the full NFA simulation." +/// However, we cannot say things like, "always execute the pure literals +/// engine" or "always execute the DFA" because they only work on a subset of +/// regexes supported by this crate. Specifically, the only way to run the +/// DFA or literal engines is to use Automatic. +#[doc(hidden)] +#[derive(Clone, Copy, Debug)] +enum MatchEngine { + /// Automatically choose the best matching engine based on heuristics. + Automatic, + /// A bounded backtracking implementation. About twice as fast as the + /// NFA, but can only work on small regexes and small input. + Backtrack, + /// A full NFA simulation. Can always be employed but almost always the + /// slowest choice. + Nfa, +} diff --git a/src/input.rs b/src/input.rs index 446872bb46..dacb36cc0f 100644 --- a/src/input.rs +++ b/src/input.rs @@ -11,13 +11,14 @@ use std::ops; use char::Char; -use prefix::Prefix; +use literals::Literals; /// Represents a location in the input. #[derive(Clone, Copy, Debug)] pub struct InputAt { pos: usize, c: Char, + byte: Option, len: usize, } @@ -27,6 +28,11 @@ impl InputAt { self.pos == 0 } + /// Returns true iff this position is past the end of the input. + pub fn is_end(&self) -> bool { + self.c.is_none() && self.byte.is_none() + } + /// Returns the character at this position. /// /// If this position is just before or after the input, then an absent @@ -35,6 +41,11 @@ impl InputAt { self.c } + /// Returns the byte at this position. + pub fn byte(&self) -> Option { + self.byte + } + /// Returns the UTF-8 width of the character at this position. pub fn len(&self) -> usize { self.len @@ -55,16 +66,40 @@ impl InputAt { pub trait Input { /// Return an encoding of the position at byte offset `i`. fn at(&self, i: usize) -> InputAt; - /// Return an encoding of the char position just prior to byte offset `i`. - fn previous_at(&self, i: usize) -> InputAt; + + /// Return the Unicode character occurring next to `at`. + /// + /// If no such character could be decoded, then `Char` is absent. + fn next_char(&self, at: InputAt) -> Char; + + /// Return the Unicode character occurring previous to `at`. + /// + /// If no such character could be decoded, then `Char` is absent. + fn previous_char(&self, at: InputAt) -> Char; + /// Scan the input for a matching prefix. - fn prefix_at(&self, prefixes: &Prefix, at: InputAt) -> Option; + fn prefix_at(&self, prefixes: &Literals, at: InputAt) -> Option; + + /// The number of bytes in the input. + fn len(&self) -> usize; + + /// Return the given input as a sequence of bytes. + fn as_bytes(&self) -> &[u8]; +} + +impl<'a, T: Input> Input for &'a T { + fn at(&self, i: usize) -> InputAt { (**self).at(i) } + fn next_char(&self, at: InputAt) -> Char { (**self).next_char(at) } + fn previous_char(&self, at: InputAt) -> Char { (**self).previous_char(at) } + fn prefix_at(&self, prefixes: &Literals, at: InputAt) -> Option { + (**self).prefix_at(prefixes, at) + } + fn len(&self) -> usize { (**self).len() } + fn as_bytes(&self) -> &[u8] { (**self).as_bytes() } } /// An input reader over characters. -/// -/// (This is the only implementation of `Input` at the moment.) -#[derive(Debug)] +#[derive(Clone, Copy, Debug)] pub struct CharInput<'t>(&'t str); impl<'t> CharInput<'t> { @@ -94,21 +129,87 @@ impl<'t> Input for CharInput<'t> { InputAt { pos: i, c: c, + byte: None, len: c.len_utf8(), } } - fn previous_at(&self, i: usize) -> InputAt { - let c: Char = self[..i].chars().rev().next().into(); - let len = c.len_utf8(); + fn next_char(&self, at: InputAt) -> Char { + at.char() + } + + fn previous_char(&self, at: InputAt) -> Char { + self[..at.pos()].chars().rev().next().into() + } + + fn prefix_at(&self, prefixes: &Literals, at: InputAt) -> Option { + prefixes + .find(&self.as_bytes()[at.pos()..]) + .map(|(s, _)| self.at(at.pos() + s)) + } + + fn len(&self) -> usize { + self.0.len() + } + + fn as_bytes(&self) -> &[u8] { + self.0.as_bytes() + } +} + +/// An input reader over bytes. +/// +/// N.B. We represent the reader with a string for now, since that gives us +/// easy access to necessary Unicode decoding (used for word boundary look +/// ahead/look behind). +#[derive(Clone, Copy, Debug)] +pub struct ByteInput<'t>(&'t str); + +impl<'t> ByteInput<'t> { + /// Return a new byte-based input reader for the given string. + pub fn new(s: &'t str) -> ByteInput<'t> { + ByteInput(s) + } +} + +impl<'t> ops::Deref for ByteInput<'t> { + type Target = str; + + fn deref(&self) -> &str { + self.0 + } +} + +impl<'t> Input for ByteInput<'t> { + #[inline(always)] + fn at(&self, i: usize) -> InputAt { InputAt { - pos: i - len, - c: c, - len: len, + pos: i, + c: None.into(), + byte: self.as_bytes().get(i).map(|&b| b), + len: 1, } } - fn prefix_at(&self, prefixes: &Prefix, at: InputAt) -> Option { - prefixes.find(&self[at.pos()..]).map(|(s, _)| self.at(at.pos() + s)) + fn next_char(&self, at: InputAt) -> Char { + self[at.pos()..].chars().next().into() + } + + fn previous_char(&self, at: InputAt) -> Char { + self[..at.pos()].chars().rev().next().into() + } + + fn prefix_at(&self, prefixes: &Literals, at: InputAt) -> Option { + prefixes + .find(&self.as_bytes()[at.pos()..]) + .map(|(s, _)| self.at(at.pos() + s)) + } + + fn len(&self) -> usize { + self.0.len() + } + + fn as_bytes(&self) -> &[u8] { + self.0.as_bytes() } } diff --git a/src/inst.rs b/src/inst.rs index 078a5b3f07..8827df85a5 100644 --- a/src/inst.rs +++ b/src/inst.rs @@ -1,11 +1,243 @@ use std::cmp::Ordering; +use std::fmt; +use std::ops::Deref; +use std::mem; +use std::slice; use char::Char; +use literals::{BuildPrefixes, Literals}; -/// InstIdx represents the index of an instruction in a regex program. -pub type InstIdx = usize; +/// InstPtr represents the index of an instruction in a regex program. +pub type InstPtr = usize; + +/// Insts is a sequence of instructions. +#[derive(Clone)] +pub struct Insts { + insts: Vec, + bytes: bool, + reverse: bool, + byte_classes: Vec, +} + +impl Insts { + /// Create a new instruction sequence. + /// + /// If `bytes` is true, then this instruction sequence must run on raw + /// bytes. Otherwise, it is executed on Unicode codepoints. + /// + /// A Vec can be created with the compiler. + pub fn new( + insts: Vec, + bytes: bool, + reverse: bool, + byte_classes: Vec, + ) -> Self { + assert!(byte_classes.len() == 256); + Insts { + insts: insts, + bytes: bytes, + reverse: reverse, + byte_classes: byte_classes, + } + } + + /// Returns true if and only if this instruction sequence must be executed + /// on byte strings. + pub fn is_bytes(&self) -> bool { + self.bytes + } + + /// Returns true if and only if this instruction sequence is reversed. + pub fn is_reversed(&self) -> bool { + self.reverse + } + + /// If pc is an index to a no-op instruction (like Save), then return the + /// next pc that is not a no-op instruction. + pub fn skip(&self, mut pc: usize) -> usize { + loop { + match self[pc] { + Inst::Save(ref i) => pc = i.goto, + _ => return pc, + } + } + } + + /// Returns a map from input byte to byte class. Each class represents + /// a set of bytes that are indistinguishable to the underlying + /// instructions. + /// + /// It is guaranteed to have length 256. + pub fn byte_classes(&self) -> &[usize] { + &self.byte_classes + } + + /// Returns the location of the `Save(0)` instruction, which is present + /// in every program and always indicates the logical start of a match. + /// + /// (DFA programs compile a `.*?` into the program, preceding the `Save(0)` + /// instruction, to support unanchored matches. Generally, we want to + /// ignore that `.*?` when doing analysis, like extracting prefixes.) + pub fn start(&self) -> InstPtr { + for (i, inst) in self.iter().enumerate() { + match *inst { + Inst::Save(ref inst) if inst.slot == 0 => return i, + _ => {} + } + } + unreachable!() + } + + /// Return true if and only if an execution engine at instruction `pc` will + /// always lead to a match. + pub fn leads_to_match(&self, pc: usize) -> bool { + match self[self.skip(pc)] { + Inst::Match => true, + _ => false, + } + } + + /// Return true if and only if the regex is anchored at the start of + /// search text. + pub fn anchored_begin(&self) -> bool { + match self.get(1) { + Some(&Inst::EmptyLook(ref inst)) => { + inst.look == EmptyLook::StartText + } + _ => false, + } + } + + /// Return true if and only if the regex is anchored at the end of + /// search text. + pub fn anchored_end(&self) -> bool { + match self.get(self.len() - 3) { + Some(&Inst::EmptyLook(ref inst)) => { + inst.look == EmptyLook::EndText + } + _ => false, + } + } + + /// Build a matching engine for all prefix literals in this instruction + /// sequence. + /// + /// If there are no prefix literals (or there are too many), then a + /// matching engine that never matches is returned. + pub fn prefix_matcher(&self) -> Literals { + if self.is_bytes() || self.is_reversed() { + Literals::empty() + } else { + BuildPrefixes::new(self).literals().into_matcher() + } + } + + /// Return the approximate heap usage of this instruction sequence in + /// bytes. + pub fn approximate_size(&self) -> usize { + // The only instruction that uses heap space is Ranges (for + // Unicode codepoint programs) to store non-overlapping codepoint + // ranges. To keep this operation constant time, we ignore them. + self.len() * mem::size_of::() + } +} + +impl Deref for Insts { + type Target = [Inst]; + + fn deref(&self) -> &Self::Target { + &*self.insts + } +} + +impl fmt::Debug for Insts { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + use self::Inst::*; + + fn with_goto(cur: usize, goto: usize, fmtd: String) -> String { + if goto == cur + 1 { + fmtd + } else { + format!("{} (goto: {})", fmtd, goto) + } + } + + fn visible_byte(b: u8) -> String { + use std::ascii::escape_default; + let escaped = escape_default(b).collect::>(); + String::from_utf8_lossy(&escaped).into_owned() + } + + try!(writeln!(f, "--------------------------------")); + for (pc, inst) in self.iter().enumerate() { + match *inst { + Match => try!(writeln!(f, "{:04} Match", pc)), + Save(ref inst) => { + let s = format!("{:04} Save({})", pc, inst.slot); + try!(writeln!(f, "{}", with_goto(pc, inst.goto, s))); + } + Split(ref inst) => { + try!(writeln!(f, "{:04} Split({}, {})", + pc, inst.goto1, inst.goto2)); + } + EmptyLook(ref inst) => { + let s = format!("{:?}", inst.look); + try!(writeln!(f, "{:04} {}", + pc, with_goto(pc, inst.goto, s))); + } + Char(ref inst) => { + let s = format!("{:?}", inst.c); + try!(writeln!(f, "{:04} {}", + pc, with_goto(pc, inst.goto, s))); + } + Ranges(ref inst) => { + let ranges = inst.ranges + .iter() + .map(|r| format!("{:?}-{:?}", r.0, r.1)) + .collect::>() + .join(", "); + let s = format!("{}", ranges); + try!(writeln!(f, "{:04} {}", + pc, with_goto(pc, inst.goto, s))); + } + Bytes(ref inst) => { + let s = format!( + "Bytes({}, {})", + visible_byte(inst.start), + visible_byte(inst.end)); + try!(writeln!(f, "{:04} {}", + pc, with_goto(pc, inst.goto, s))); + } + } + } + try!(writeln!(f, "--------------------------------")); + Ok(()) + } +} + +impl<'a> IntoIterator for &'a Insts { + type Item = &'a Inst; + type IntoIter = slice::Iter<'a, Inst>; + fn into_iter(self) -> Self::IntoIter { self.iter() } +} /// Inst is an instruction code in a Regex program. +/// +/// Regrettably, a regex program either contains Unicode codepoint +/// instructions (Char and Ranges) or it contains byte instructions (Bytes). +/// A regex program can never contain both. +/// +/// It would be worth investigating splitting this into two distinct types and +/// then figuring out how to make the matching engines polymorphic over those +/// types without sacrificing performance. +/// +/// Other than the benefit of moving invariants into the type system, another +/// benefit is the decreased size. If we remove the `Char` and `Ranges` +/// instructions from the `Inst` enum, then its size shrinks from 40 bytes to +/// 24 bytes. (This is because of the removal of a `Vec` in the `Ranges` +/// variant.) Given that byte based machines are typically much bigger than +/// their Unicode analogues (because they can decode UTF-8 directly), this ends +/// up being a pretty significant savings. #[derive(Clone, Debug)] pub enum Inst { /// Match indicates that the program has reached a match state. @@ -25,13 +257,17 @@ pub enum Inst { /// Ranges requires the regex program to match the character at the current /// position in the input with one of the ranges specified in InstRanges. Ranges(InstRanges), + /// Bytes is like Ranges, except it expresses a single byte range. It is + /// used in conjunction with Split instructions to implement multi-byte + /// character classes. + Bytes(InstBytes), } /// Representation of the Save instruction. #[derive(Clone, Debug)] pub struct InstSave { /// The next location to execute in the program. - pub goto: InstIdx, + pub goto: InstPtr, /// The capture slot (there are two slots for every capture in a regex, /// including the zeroth capture for the entire match). pub slot: usize, @@ -42,10 +278,10 @@ pub struct InstSave { pub struct InstSplit { /// The first instruction to try. A match resulting from following goto1 /// has precedence over a match resulting from following goto2. - pub goto1: InstIdx, + pub goto1: InstPtr, /// The second instruction to try. A match resulting from following goto1 /// has precedence over a match resulting from following goto2. - pub goto2: InstIdx, + pub goto2: InstPtr, } /// Representation of the EmptyLook instruction. @@ -53,7 +289,7 @@ pub struct InstSplit { pub struct InstEmptyLook { /// The next location to execute in the program if this instruction /// succeeds. - pub goto: InstIdx, + pub goto: InstPtr, /// The type of zero-width assertion to check. pub look: EmptyLook, } @@ -99,7 +335,7 @@ impl InstEmptyLook { pub struct InstChar { /// The next location to execute in the program if this instruction /// succeeds. - pub goto: InstIdx, + pub goto: InstPtr, /// The character to test. pub c: char, } @@ -109,7 +345,7 @@ pub struct InstChar { pub struct InstRanges { /// The next location to execute in the program if this instruction /// succeeds. - pub goto: InstIdx, + pub goto: InstPtr, /// The set of Unicode scalar value ranges to test. pub ranges: Vec<(char, char)>, } @@ -139,4 +375,32 @@ impl InstRanges { } }).is_ok() } + + /// Return the number of distinct characters represented by all of the + /// ranges. + pub fn num_chars(&self) -> usize { + self.ranges.iter() + .map(|&(s, e)| 1 + (e as u32) - (s as u32)) + .fold(0, |acc, len| acc + len) + as usize + } +} + +/// Representation of the Bytes instruction. +#[derive(Clone, Debug)] +pub struct InstBytes { + /// The next location to execute in the program if this instruction + /// succeeds. + pub goto: InstPtr, + /// The start (inclusive) of this byte range. + pub start: u8, + /// The end (inclusive) of this byte range. + pub end: u8, +} + +impl InstBytes { + /// Returns true if and only if the given byte is in this range. + pub fn matches(&self, byte: u8) -> bool { + self.start <= byte && byte <= self.end + } } diff --git a/src/lib.rs b/src/lib.rs index d30c41c0f8..84d26fb64d 100644 --- a/src/lib.rs +++ b/src/lib.rs @@ -35,7 +35,7 @@ //! extern crate regex; //! ``` //! -//! # First example: find a date +//! # Example: find a date //! //! General use of regular expressions in this package involves compiling an //! expression and then using it to search, split or replace text. For example, @@ -59,6 +59,40 @@ //! not process any escape sequences. For example, `"\\d"` is the same //! expression as `r"\d"`. //! +//! # Example: Avoid compiling the same regex in a loop +//! +//! It is an anti-pattern to compile the same regular expression in a loop +//! since compilation is typically expensive. (It takes anywhere from a few +//! microseconds to a few **milliseconds** depending on the size of the +//! regex.) Not only is compilation itself expensive, but this also prevents +//! optimizations that reuse allocations internally to the matching engines. +//! +//! In Rust, it can sometimes be a pain to pass regular expressions around if +//! they're used from inside a helper function. Instead, we recommend using the +//! [`lazy_static`](https://crates.io/crates/lazy_static) crate to ensure that +//! regular expressions are compiled exactly once. +//! +//! For example: +//! +//! ```rust +//! #[macro_use] extern crate lazy_static; +//! extern crate regex; +//! +//! use regex::Regex; +//! +//! fn some_helper_function(text: &str) -> bool { +//! lazy_static! { +//! static ref RE: Regex = Regex::new("...").unwrap(); +//! } +//! RE.is_match(text) +//! } +//! +//! fn main() {} +//! ``` +//! +//! Specifically, in this example, the regex will be compiled when it is used for +//! the first time. On subsequent uses, it will reuse the previous compilation. +//! //! # The `regex!` macro //! //! Rust's compile-time meta-programming facilities provide a way to write a @@ -69,15 +103,15 @@ //! given expression to native Rust code, which ideally makes it faster. //! Unfortunately (or fortunately), the dynamic implementation has had a lot //! more optimization work put into it currently, so it is faster than -//! the `regex!` macro in most cases. +//! the `regex!` macro in almost every case. //! //! To use the `regex!` macro, you must add `regex_macros` to your dependencies //! in your project's `Cargo.toml`: //! //! ```toml //! [dependencies] -//! regex = "0.1.8" -//! regex_macros = "0.1.8" +//! regex = "0.1" +//! regex_macros = "0.1" //! ``` //! //! and then enable the `plugin` feature and import the `regex_macros` crate as @@ -107,7 +141,7 @@ //! //! **NOTE**: This is implemented using a compiler plugin, which is not //! available on the Rust 1.0 beta/stable channels. Therefore, you'll only -//! be able to use `regex!` on the nightlies. +//! be able to use `regex!` on the nightly Rust releases. //! //! # Example: iterating over capture groups //! @@ -196,18 +230,17 @@ //! //! # Unicode //! -//! This implementation executes regular expressions **only** on sequences of -//! Unicode scalar values while exposing match locations as byte indices into -//! the search string. +//! This implementation executes regular expressions **only** on valid UTF-8 +//! while exposing match locations as byte indices into the search string. //! //! Currently, only simple case folding is supported. Namely, when matching //! case-insensitively, the characters are first mapped using the //! [simple case folding](ftp://ftp.unicode.org/Public/UNIDATA/CaseFolding.txt) //! mapping. //! -//! Regular expressions themselves are also **only** interpreted as a sequence -//! of Unicode scalar values. This means you can use Unicode characters -//! directly in your expression: +//! Regular expressions themselves are **only** interpreted as a sequence of +//! Unicode scalar values. This means you can use Unicode characters directly +//! in your expression: //! //! ```rust //! # extern crate regex; use regex::Regex; @@ -235,8 +268,7 @@ //! with the syntax supported by RE2. It is documented below. //! //! Note that the regular expression parser and abstract syntax are exposed in -//! a separate crate, -//! [`regex-syntax`](../regex_syntax/index.html). +//! a separate crate, [`regex-syntax`](../regex_syntax/index.html). //! //! ## Matching one character //! @@ -397,6 +429,14 @@ //! text`), which means there's no way to cause exponential blow-up like with //! some other regular expression engines. (We pay for this by disallowing //! features like arbitrary look-ahead and backreferences.) +//! +//! When a DFA is used, pathological cases with exponential state blow up are +//! avoided by constructing the DFA lazily or in an "online" manner. Therefore, +//! at most one new state can be created for each byte of input. This satisfies +//! our time complexity guarantees, but can lead to unbounded memory growth +//! proportional to the size of the input. As a stopgap, the DFA is only +//! allowed to store a fixed number of states. (When the limit is reached, its +//! states are wiped and continues on, possibly duplicating previous work.) #![deny(missing_docs)] #![cfg_attr(test, deny(warnings))] @@ -408,7 +448,9 @@ extern crate aho_corasick; extern crate memchr; extern crate regex_syntax as syntax; +extern crate utf8_ranges; +// The re module is essentially our public interface. pub use re::{ Regex, Error, Captures, SubCaptures, SubCapturesPos, SubCapturesNamed, CaptureNames, FindCaptures, FindMatches, @@ -418,23 +460,27 @@ pub use re::{ mod backtrack; mod char; +mod char_utf8; mod compile; +mod dfa; +mod exec; mod input; mod inst; +mod literals; +mod nfa; mod pool; -mod prefix; mod program; -mod nfa; mod re; +mod sparse; /// The `internal` module exists to support the `regex!` macro and other /// suspicious activity, such as testing different matching engines. #[doc(hidden)] pub mod internal { pub use char::Char; + pub use exec::{Exec, ExecBuilder}; pub use input::{Input, CharInput, InputAt}; pub use inst::{Inst, EmptyLook, InstRanges}; - pub use program::{Program, MatchEngine}; + pub use program::{Program, ProgramBuilder}; pub use re::ExNative; - pub use re::Regex::{Dynamic, Native}; } diff --git a/src/literals.rs b/src/literals.rs new file mode 100644 index 0000000000..c6283d723b --- /dev/null +++ b/src/literals.rs @@ -0,0 +1,714 @@ +// Copyright 2014-2015 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +use std::char; +use std::collections::HashSet; +use std::fmt; +use std::mem; + +use aho_corasick::{Automaton, AcAutomaton, FullAcAutomaton}; +use memchr::{memchr, memchr2, memchr3}; + +use char_utf8::encode_utf8; +use inst::{Insts, Inst, InstBytes, InstRanges}; + +pub struct AlternateLiterals { + at_match: bool, + literals: Vec>, +} + +impl AlternateLiterals { + pub fn into_matcher(self) -> Literals { + if self.literals.is_empty() { + Literals::empty() + } else { + let at_match = self.at_match; + Literals { + at_match: at_match, + matcher: LiteralMatcher::new(self), + } + } + } + + fn empty() -> AlternateLiterals { + AlternateLiterals { at_match: false, literals: vec![] } + } + + fn is_empty(&self) -> bool { + self.literals.is_empty() + } + + fn is_single_byte(&self) -> bool { + self.literals.len() == 1 && self.literals[0].len() == 1 + } + + fn all_single_bytes(&self) -> bool { + self.literals.len() >= 1 && self.literals.iter().all(|s| s.len() == 1) + } + + fn is_one_literal(&self) -> bool { + self.literals.len() == 1 + } + + fn distinct_single_bytes(&self) -> usize { + let mut seen = vec![false; 256]; + for lit in &self.literals { + if lit.len() == 1 { + seen[lit[0] as usize] = true; + } + } + seen.iter().filter(|yes| **yes).count() + } + + fn num_bytes(&self) -> usize { + self.literals.iter().map(|lit| lit.len()).fold(0, |acc, len| acc + len) + } + + fn add_alternates(&mut self, alts: AlternateLiterals) { + self.at_match = self.at_match && alts.at_match; + self.literals.extend(alts.literals); + } + + fn add_literal_char(&mut self, c: char) { + let scratch = &mut [0; 4]; + let n = encode_utf8(c, scratch).unwrap(); + for alt in &mut self.literals { + alt.extend(&scratch[0..n]); + } + } + + fn add_literal_char_ranges(&mut self, inst: &InstRanges) { + // This is tricky. We need to think of each range as its own set of + // alternations. For example, `[a-cx-z]` is comprised of two ranges: + // `a-c` and `x-z`. This is equivalent to the regex `a|b|c|x|y|z`. If + // we've already found two prefixes, e.g., `foo|bar`, then we need to + // extend all such prefixes with all alternates here. For e.g., `fooa`, + // ..., `fooz`, `bara`, ..., `barz`. + // + // To achieve this, we copy our existing literals for every char! + let scratch = &mut [0; 4]; + let nlits = self.literals.len(); + let orig = mem::replace(&mut self.literals, Vec::with_capacity(nlits)); + for &(s, e) in &inst.ranges { + for c in (s as u32)..(e as u32 + 1) { + for alt in &orig { + let mut alt = alt.clone(); + let ch = char::from_u32(c).unwrap(); + let n = encode_utf8(ch, scratch).unwrap(); + + alt.extend(&scratch[0..n]); + self.literals.push(alt); + } + } + } + } + + fn add_literal_byte_range(&mut self, inst: &InstBytes) { + // Pretty much the same process as for literal char ranges, but we + // only have one range. + let nlits = self.literals.len(); + let orig = mem::replace(&mut self.literals, Vec::with_capacity(nlits)); + for b in inst.start..(inst.end + 1) { + for alt in &orig { + let mut alt = alt.clone(); + alt.push(b); + self.literals.push(alt); + } + } + } +} + +pub struct BuildPrefixes<'a> { + insts: &'a Insts, + limit: usize, + alts: AlternateLiterals, +} + +impl<'a> BuildPrefixes<'a> { + pub fn new(insts: &'a Insts) -> Self { + BuildPrefixes { + insts: insts, + limit: 250, + alts: AlternateLiterals { at_match: true, literals: vec![] }, + } + } + + pub fn literals(mut self) -> AlternateLiterals { + let mut stack = vec![self.insts.skip(self.insts.start())]; + let mut seen = HashSet::new(); + while let Some(mut pc) = stack.pop() { + seen.insert(pc); + pc = self.insts.skip(pc); + if let Inst::Split(ref inst) = self.insts[pc] { + if !seen.contains(&inst.goto2) { + stack.push(inst.goto2); + } + if !seen.contains(&inst.goto1) { + stack.push(inst.goto1); + } + continue; + } + // When searching for required literals, set the local limit to + // something a bit less than our real limit. This prevents a single + // alternation from blowing our budget in most cases. (If a single + // alt blows the budget, then we can't consume literals from other + // alts, which means we end up with nothing to show for it.) + // + // For example, consider `a?[0-9]{3}`. This splits into two + // regexes `a[0-9]{3}` and `[0-9]{3}`. The latter regex can be + // expanded completely into a set of alternate literals that + // consumes exactly 3000 bytes. This is our entire budget if the + // limit is 3000. Therefore, we're left with no room to add the + // second branch (`a[0-9]{3}`) to our set of literals. If we can't + // represent all required alternates, then we have to give up. + // Therefore, as a heuristic, limit what each alternate is allowed + // to use. In this case, `[0-9]{3}` will only gather literals for + // `[0-9]{2}`, which leaves more than enough room for our second + // branch. + let alts = BuildRequiredLiterals::new(self.insts) + .set_limit(self.limit / 10) + .literals(pc); + if alts.is_empty() { + // If we couldn't find any literals required in this path + // through the program, then we can't conclude anything about + // prefix literals for this program. For example, if the regex + // is `a|b*`, then the second alternate has no prefix to search + // for. (`b*` matches the empty string!) + return AlternateLiterals::empty(); + } + if self.alts.num_bytes() + alts.num_bytes() > self.limit { + // We've blown our budget. Give up. + // We could do something a little smarter here and try to trim + // the literals we've got here. (e.g., If every literal is two + // characters, then it would be legal to remove the second char + // from every literal.) + return AlternateLiterals::empty(); + } + self.alts.add_alternates(alts); + } + self.alts + } +} + +pub struct BuildRequiredLiterals<'a> { + insts: &'a Insts, + limit: usize, + alts: AlternateLiterals, +} + +impl<'a> BuildRequiredLiterals<'a> { + pub fn new(insts: &'a Insts) -> Self { + BuildRequiredLiterals { + insts: insts, + limit: 250, + alts: AlternateLiterals { at_match: true, literals: vec![vec![]] }, + } + } + + pub fn set_limit(mut self, limit: usize) -> Self { + self.limit = limit; + self + } + + fn literals(mut self, mut pc: usize) -> AlternateLiterals { + use inst::Inst::*; + loop { + let inst = &self.insts[pc]; + match *inst { + Save(ref inst) => pc = inst.goto, + Char(ref inst) => { + if !self.add_literal_char(inst.c) { + self.alts.at_match = false; + break; + } + pc = inst.goto; + } + Ranges(ref inst) => { + if !self.add_literal_char_ranges(inst) { + self.alts.at_match = false; + break; + } + pc = inst.goto; + } + Bytes(ref inst) => { + if !self.add_literal_byte_range(inst) { + self.alts.at_match = false; + break; + } + pc = inst.goto; + } + Split(_) | EmptyLook(_) | Match => { + self.alts.at_match = self.insts.leads_to_match(pc); + break; + } + } + } + if self.alts.literals.len() == 1 && self.alts.literals[0].is_empty() { + AlternateLiterals::empty() + } else { + self.alts + } + } + + fn add_literal_char(&mut self, c: char) -> bool { + if self.alts.num_bytes() + 1 > self.limit { + return false; + } + self.alts.add_literal_char(c); + true + } + + fn add_literal_char_ranges(&mut self, inst: &InstRanges) -> bool { + // Compute roughly how many bytes will be in our literals following + // the addition of the given ranges. If we blow our limit, then we + // can't add *any* of them. + let nchars = inst.num_chars(); + let new_byte_count = (self.alts.num_bytes() * nchars) + + (self.alts.literals.len() * nchars); + if new_byte_count > self.limit { + return false; + } + self.alts.add_literal_char_ranges(inst); + true + } + + fn add_literal_byte_range(&mut self, inst: &InstBytes) -> bool { + // Compute roughly how many bytes will be in our literals following + // the addition of the given range. If we blow our limit, then we + // can't add anything. + let nbytes = (inst.end - inst.start + 1) as usize; + let new_byte_count = (self.alts.num_bytes() * nbytes) + + (self.alts.literals.len() * nbytes); + if new_byte_count > self.limit { + return false; + } + self.alts.add_literal_byte_range(inst); + true + } +} + +/// A prefix extracted from a compiled regular expression. +/// +/// A regex prefix is a set of literal strings that *must* be matched at the +/// beginning of a regex in order for the entire regex to match. +/// +/// There are a variety of ways to efficiently scan the search text for a +/// prefix. Currently, there are three implemented: +/// +/// 1. The prefix is a single byte. Just use memchr. +/// 2. If the prefix is a set of two or more single byte prefixes, then +/// a single sparse map is created. Checking if there is a match is a lookup +/// in this map for each byte in the search text. +/// 3. In all other cases, build an Aho-Corasick automaton. +/// +/// It's possible that there's room here for other substring algorithms, +/// such as Boyer-Moore for single-set prefixes greater than 1, or Rabin-Karp +/// for small sets of same-length prefixes. +#[derive(Clone)] +pub struct Literals { + at_match: bool, + matcher: LiteralMatcher, +} + +#[derive(Clone)] +enum LiteralMatcher { + /// No prefixes. (Never advances through the input.) + Empty, + /// A single byte prefix. + Byte(u8), + /// A set of two or more single byte prefixes. + /// This could be reduced to a bitset, which would use only 8 bytes, + /// but I don't think we care. + Bytes { + chars: Vec, + sparse: Vec, + }, + Single(SingleSearch), + /// A full Aho-Corasick DFA. A "full" DFA in this case means that all of + /// the failure transitions have been expanded and the entire DFA is + /// represented by a memory inefficient sparse matrix. This makes matching + /// extremely fast. We only use this "full" DFA when the number of bytes + /// in our literals does not exceed 250. This generally leads to a DFA that + /// consumes 250KB of memory. + FullAutomaton(FullAcAutomaton>), +} + +impl Literals { + /// Returns a matcher that never matches and never advances the input. + pub fn empty() -> Self { + Literals { at_match: false, matcher: LiteralMatcher::Empty } + } + + /// Returns true if and only if a literal match corresponds to a match + /// in the regex from which the literal was extracted. + pub fn at_match(&self) -> bool { + self.at_match && self.len() > 0 + } + + /// Find the position of a prefix in `haystack` if it exists. + /// + /// In the matching engines, we only actually need the starting index + /// because the prefix is used to only skip ahead---the matching engine + /// still needs to run over the prefix input. However, we return the ending + /// location as well in case the prefix corresponds to the entire regex, + /// in which case, you need the end of the match. + pub fn find(&self, haystack: &[u8]) -> Option<(usize, usize)> { + use self::LiteralMatcher::*; + match self.matcher { + Empty => Some((0, 0)), + Byte(b) => memchr(b, haystack).map(|i| (i, i+1)), + Bytes { ref sparse, ref chars } => { + if chars.len() == 2 { + memchr2(chars[0], chars[1], haystack).map(|i| (i, i+1)) + } else if chars.len() == 3 { + let (b0, b1, b2) = (chars[0], chars[1], chars[2]); + memchr3(b0, b1, b2, haystack).map(|i| (i, i+1)) + } else { + find_singles(sparse, haystack) + } + } + Single(ref searcher) => { + searcher.find(haystack).map(|i| (i, i + searcher.pat.len())) + } + FullAutomaton(ref aut) => { + aut.find(haystack).next().map(|m| (m.start, m.end)) + } + } + } + + /// Returns true iff this prefix is empty. + pub fn is_empty(&self) -> bool { + self.len() == 0 + } + + /// Returns the number of prefixes in this machine. + pub fn len(&self) -> usize { + use self::LiteralMatcher::*; + match self.matcher { + Empty => 0, + Byte(_) => 1, + Bytes { ref chars, .. } => chars.len(), + Single(_) => 1, + FullAutomaton(ref aut) => aut.len(), + } + } + + /// Returns true iff the prefix match preserves priority. + /// + /// For example, given the alternation `ab|a` and the target string `ab`, + /// does the prefix machine guarantee that `ab` will match? (A full + /// Aho-Corasick automaton does not!) + pub fn preserves_priority(&self) -> bool { + use self::LiteralMatcher::*; + match self.matcher { + Empty => true, + Byte(_) => true, + Bytes{..} => true, + Single(_) => true, + FullAutomaton(ref aut) => { + // Okay, so the automaton can respect priority in one + // particular case: when every pattern is of the same length. + // The trick is that the automaton will report the leftmost + // match, which in this case, corresponds to the correct + // match for the regex engine. If any other alternate matches + // at the same position, then they must be exactly equivalent. + + // Guaranteed at least one prefix by construction, so use + // that for the length. + aut.patterns().iter().all(|p| p.len() == aut.pattern(0).len()) + } + } + } + + /// Return the approximate heap usage of literals in bytes. + pub fn approximate_size(&self) -> usize { + use self::LiteralMatcher::*; + match self.matcher { + Empty | Byte(_) => 0, + Bytes { ref chars, ref sparse } => { + (chars.len() * mem::size_of::()) + + (sparse.len() * mem::size_of::()) + } + Single(ref single) => { + (single.pat.len() * mem::size_of::()) + + (single.shift.len() * mem::size_of::()) + } + FullAutomaton(ref aut) => aut.heap_bytes(), + } + } + + /// Returns all of the prefixes participating in this machine. + /// + /// For debug/testing only! (It allocates.) + #[allow(dead_code)] + fn prefixes(&self) -> Vec { + self.byte_prefixes() + .into_iter() + .map(|p| String::from_utf8(p).unwrap()) + .collect() + } + + #[allow(dead_code)] + fn byte_prefixes(&self) -> Vec> { + use self::LiteralMatcher::*; + match self.matcher { + Empty => vec![], + Byte(b) => vec![vec![b]], + Bytes { ref chars, .. } => { + chars.iter().map(|&byte| vec![byte]).collect() + } + Single(ref searcher) => vec![searcher.pat.clone()], + FullAutomaton(ref aut) => aut.patterns().iter().cloned().collect(), + } + } +} + +impl LiteralMatcher { + /// Create a new prefix matching machine. + fn new(mut alts: AlternateLiterals) -> Self { + use self::LiteralMatcher::*; + + if alts.is_empty() { + Empty + } else if alts.distinct_single_bytes() >= 26 { + // Why do we do this? Well, it's a heuristic to prevent thrashing. + // Basically, if our literal matcher has lots of literals that are + // a single byte, then we lose a lot of the benefits of fast + // literal searching. In particular, single bytes have a high + // probability of matching. In a regex that rarely matches, we end + // up ping-ponging between the literal matcher and the regex engine + // for every byte of input. That's bad juju. + // + // Note that we only count distinct starting bytes from literals of + // length 1. For literals longer than that, we assume they have + // a lower probability of matching. + // + // This particular heuristic would be triggered on, e.g., + // `[a-z].+`. The prefix here is a single byte that is very likely + // to match on any given byte in the input, so it's quicker just + // to let the matching engine process it. + // + // TODO(burntsushi): Consider lowering the threshold! + Empty + } else if alts.is_single_byte() { + Byte(alts.literals[0][0]) + } else if alts.all_single_bytes() { + let mut set = vec![false; 256]; + let mut bytes = vec![]; + for lit in alts.literals { + bytes.push(lit[0]); + set[lit[0] as usize] = true; + } + Bytes { chars: bytes, sparse: set } + } else if alts.is_one_literal() { + Single(SingleSearch::new(alts.literals.pop().unwrap())) + } else { + FullAutomaton(AcAutomaton::new(alts.literals).into_full()) + } + } +} + +/// Provides an implementation of fast subtring search. +/// +/// In particular, this uses Boyer-Moore-Horspool with Tim Raita's twist: +/// https://en.wikipedia.org/wiki/Raita_Algorithm +/// +/// I'm skeptical of the utility here, because benchmarks suggest that it is +/// difficult to beat Aho-Corasick on random text. Namely, both algorithms are +/// dominated by the performance of `memchr` for the leading byte prefix. +/// With that said, BMH does seem to surpass AC when the search text gets +/// longer (see the `easy0_1MB` vs. `easy1_1MB` benchmarks). +/// +/// More analysis needs to be done to test this on different search texts. +#[derive(Clone, Debug)] +pub struct SingleSearch { + pat: Vec, + shift: Vec, +} + +impl SingleSearch { + fn new(pat: Vec) -> SingleSearch { + assert!(pat.len() >= 1); + let mut shift = vec![pat.len(); 256]; + for i in 0..(pat.len() - 1) { + shift[pat[i] as usize] = pat.len() - i - 1; + } + SingleSearch { + pat: pat, + shift: shift, + } + } + + fn find(&self, haystack: &[u8]) -> Option { + let pat = &*self.pat; + if haystack.len() < pat.len() { + return None; + } + let mut i = match memchr(pat[0], haystack) { + None => return None, + Some(i) => i, + }; + while i <= haystack.len() - pat.len() { + let b = haystack[i + pat.len() - 1]; + if b == pat[pat.len() - 1] + && haystack[i] == pat[0] + && haystack[i + (pat.len() / 2)] == pat[pat.len() / 2] + && pat == &haystack[i..i + pat.len()] { + return Some(i); + } + i += self.shift[b as usize]; + i += match memchr(pat[0], &haystack[i..]) { + None => return None, + Some(i) => i, + }; + } + None + } +} + +/// A quick scan for multiple single byte prefixes using a sparse map. +fn find_singles( + sparse: &[bool], + text: &[u8], +) -> Option<(usize, usize)> { + for (hi, &b) in text.iter().enumerate() { + if sparse[b as usize] { + return Some((hi, hi+1)); + } + } + None +} + +impl fmt::Debug for Literals { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + use self::LiteralMatcher::*; + try!(write!(f, "complete? {}, matcher: ", self.at_match)); + match self.matcher { + Empty => write!(f, "Empty"), + Byte(b) => write!(f, "one byte: {:?}", b as char), + Bytes { ref chars, .. } => { + let chars: Vec = + chars.iter() + .map(|&c| format!("{:?}", c as char)) + .collect(); + write!(f, "alternate single bytes: {}", chars.join(", ")) + } + Single(ref searcher) => write!(f, "{:?}", searcher), + FullAutomaton(ref aut) => write!(f, "{:?}", aut), + } + } +} + +#[cfg(test)] +mod tests { + use program::ProgramBuilder; + + macro_rules! prog { + ($re:expr) => { ProgramBuilder::new($re).compile().unwrap() } + } + + macro_rules! byte_prog { + ($re:expr) => { + ProgramBuilder::new($re).bytes(true).compile().unwrap() + } + } + + macro_rules! prefixes { + ($re:expr) => {{ + let p = prog!($re); + assert!(!p.prefixes.at_match()); + p.prefixes.prefixes() + }} + } + macro_rules! prefixes_complete { + ($re:expr) => {{ + let p = prog!($re); + assert!(p.prefixes.at_match()); + p.prefixes.prefixes() + }} + } + + #[test] + fn single() { + assert_eq!(prefixes_complete!("a"), vec!["a"]); + assert_eq!(prefixes_complete!("[a]"), vec!["a"]); + assert_eq!(prefixes!("a+"), vec!["a"]); + assert_eq!(prefixes!("(?:a)+"), vec!["a"]); + assert_eq!(prefixes!("(a)+"), vec!["a"]); + } + + #[test] + fn single_alt() { + assert_eq!(prefixes_complete!("a|b"), vec!["a", "b"]); + assert_eq!(prefixes_complete!("b|a"), vec!["b", "a"]); + assert_eq!(prefixes_complete!("[a]|[b]"), vec!["a", "b"]); + assert_eq!(prefixes!("a+|b"), vec!["a", "b"]); + assert_eq!(prefixes!("a|b+"), vec!["a", "b"]); + assert_eq!(prefixes!("(?:a+)|b"), vec!["a", "b"]); + assert_eq!(prefixes!("(a+)|b"), vec!["a", "b"]); + } + + #[test] + fn many() { + assert_eq!(prefixes_complete!("abcdef"), vec!["abcdef"]); + assert_eq!(prefixes!("abcdef+"), vec!["abcdef"]); + assert_eq!(prefixes!("(?:abcdef)+"), vec!["abcdef"]); + assert_eq!(prefixes!("(abcdef)+"), vec!["abcdef"]); + } + + #[test] + fn many_alt() { + assert_eq!(prefixes_complete!("abc|def"), vec!["abc", "def"]); + assert_eq!(prefixes_complete!("def|abc"), vec!["def", "abc"]); + assert_eq!(prefixes!("abc+|def"), vec!["abc", "def"]); + assert_eq!(prefixes!("abc|def+"), vec!["abc", "def"]); + assert_eq!(prefixes!("(?:abc)+|def"), vec!["abc", "def"]); + assert_eq!(prefixes!("(abc)+|def"), vec!["abc", "def"]); + } + + #[test] + fn class() { + assert_eq!(prefixes_complete!("[0-9]"), vec![ + "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", + ]); + assert_eq!(prefixes!("[0-9]+"), vec![ + "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", + ]); + } + + #[test] + fn preceding_alt() { + assert_eq!(prefixes!("(?:a|b).+"), vec!["a", "b"]); + assert_eq!(prefixes!("(a|b).+"), vec!["a", "b"]); + } + + #[test] + fn nested_alt() { + assert_eq!(prefixes_complete!("(a|b|c|d)"), + vec!["a", "b", "c", "d"]); + assert_eq!(prefixes_complete!("((a|b)|(c|d))"), + vec!["a", "b", "c", "d"]); + } + + #[test] + fn snowman() { + assert_eq!(prefixes_complete!("☃"), vec!["☃"]); + } + + // That this test fails suggests that the literal finder needs to be + // completely rewritten. Ug. It's not that it is wrong currently, but + // it's not as good at finding literals as it should be. + /* + #[test] + fn non_contiguous() { + assert_eq!(prefixes_complete!("z(a|c)"), vec!["za", "zc"]); + } + */ +} diff --git a/src/nfa.rs b/src/nfa.rs index 9743a19875..634d1ffaaf 100644 --- a/src/nfa.rs +++ b/src/nfa.rs @@ -8,47 +8,93 @@ // option. This file may not be copied, modified, or distributed // except according to those terms. -// FIXME: Currently, the VM simulates an NFA. It would be nice to have another -// VM that simulates a DFA. +// This module implements the "NFA algorithm." That is, it guarantees linear +// time search of a regex on any text with memory use proportional to the size +// of the regex. // -// According to Russ Cox[1], a DFA performs better than an NFA, principally -// because it reuses states previously computed by the machine *and* doesn't -// keep track of capture groups. The drawback of a DFA (aside from its -// complexity) is that it can't accurately return the locations of submatches. -// The NFA *can* do that. (This is my understanding anyway.) +// It is equal in power to the backtracking engine in this crate, except the +// backtracking engine is typically faster on small regexes/texts at the +// expense of a bigger memory footprint. // -// Cox suggests that a DFA ought to be used to answer "does this match" and -// "where does it match" questions. (In the latter, the starting position of -// the match is computed by executing the regex backwards.) Cox also suggests -// that a DFA should be run when asking "where are the submatches", which can -// 1) quickly answer "no" is there's no match and 2) discover the substring -// that matches, which means running the NFA on smaller input. +// It can do more than the DFA can (specifically, record capture locations +// and execute word boundary assertions), but at a slower speed. Specifically, +// the NFA algorithm exectues a DFA implicitly by repeatedly expanding +// epsilon transitions. That is, the NFA engine can be in multiple states at +// once where as the DFA is only ever in one state at a time. // -// Currently, the NFA simulation implemented below does some dirty tricks to -// avoid tracking capture groups when they aren't needed (which only works -// for 'is_match', not 'find'). This is a half-measure, but does provide some -// perf improvement. -// -// AFAIK, the DFA/NFA approach is implemented in RE2/C++ but *not* in RE2/Go. -// -// UPDATE: We now have a backtracking matching engine and a DFA for prefix -// matching. The prefix DFA is used in both the NFA simulation below and the -// backtracking engine to skip along the input quickly. -// -// [1] - http://swtch.com/~rsc/regex/regex3.html +// Therefore, the NFA algorithm is generally treated as the fallback when the +// other matching engines either aren't feasible to run or are insufficient. -use input::{Input, InputAt, CharInput}; +use std::mem; + +use input::{Input, InputAt}; +use inst::InstPtr; use program::Program; use re::CaptureIdxs; +use sparse::SparseSet; /// An NFA simulation matching engine. #[derive(Debug)] -pub struct Nfa<'r, 't> { +pub struct Nfa<'r, I> { + /// The sequence of opcodes (among other things) that is actually executed. + /// + /// The program may be byte oriented or Unicode codepoint oriented. prog: &'r Program, - input: CharInput<'t>, + /// An explicit stack used for following epsilon transitions. (This is + /// borrowed from the cache.) + stack: &'r mut Vec, + /// The input to search. + input: I, } -impl<'r, 't> Nfa<'r, 't> { +/// A cached allocation that can be reused on each execution. +#[derive(Debug)] +pub struct NfaCache { + /// A pair of ordered sets for tracking NFA states. + clist: Threads, + nlist: Threads, + /// An explicit stack used for following epsilon transitions. + stack: Vec, +} + +/// An ordered set of NFA states and their captures. +#[derive(Debug)] +struct Threads { + /// An ordered set of opcodes (each opcode is an NFA state). + set: SparseSet, + /// Captures for every NFA state. + /// + /// It is stored in row-major order, where the columns are the capture + /// slots and the rows are the states. + caps: Vec>, + /// The number of capture slots stored per thread. (Every capture has + /// two slots.) + slots_per_thread: usize, +} + +/// A representation of an explicit stack frame when following epsilon +/// transitions. This is used to avoid recursion. +#[derive(Debug)] +enum FollowEpsilon { + /// Follow transitions at the given instruction pointer. + IP(InstPtr), + /// Restore the capture slot with the given position in the input. + Capture { slot: usize, pos: Option }, +} + +impl NfaCache { + /// Create a new allocation used by the NFA machine to record execution + /// and captures. + pub fn new() -> Self { + NfaCache { + clist: Threads::new(), + nlist: Threads::new(), + stack: vec![], + } + } +} + +impl<'r, I: Input> Nfa<'r, I> { /// Execute the NFA matching engine. /// /// If there's a match, `exec` returns `true` and populates the given @@ -56,28 +102,33 @@ impl<'r, 't> Nfa<'r, 't> { pub fn exec( prog: &'r Program, mut caps: &mut CaptureIdxs, - text: &'t str, + input: I, start: usize, ) -> bool { - let mut q = prog.nfa_threads.get(); - let input = CharInput::new(text); + let mut _cache = prog.cache_nfa(); + let mut cache = &mut **_cache; + cache.clist.resize(prog.insts.len(), prog.num_captures()); + cache.nlist.resize(prog.insts.len(), prog.num_captures()); let at = input.at(start); Nfa { prog: prog, + stack: &mut cache.stack, input: input, - }.exec_(&mut q, &mut caps, at) + }.exec_(&mut cache.clist, &mut cache.nlist, &mut caps, at) } fn exec_( &mut self, - mut q: &mut NfaThreads, + mut clist: &mut Threads, + mut nlist: &mut Threads, mut caps: &mut CaptureIdxs, mut at: InputAt, ) -> bool { let mut matched = false; - q.clist.empty(); q.nlist.empty(); + clist.set.clear(); + nlist.set.clear(); 'LOOP: loop { - if q.clist.size == 0 { + if clist.set.is_empty() { // Three ways to bail out when our current set of threads is // empty. // @@ -105,18 +156,19 @@ impl<'r, 't> Nfa<'r, 't> { // This simulates a preceding '.*?' for every regex by adding // a state starting at the current position in the input for the // beginning of the program only if we don't already have a match. - if q.clist.size == 0 || (!self.prog.anchored_begin && !matched) { - self.add(&mut q.clist, &mut caps, 0, at) + if clist.set.is_empty() + || (!self.prog.anchored_begin && !matched) { + self.add(&mut clist, &mut caps, 0, at) } // The previous call to "add" actually inspects the position just // before the current character. For stepping through the machine, // we can to look at the current character, so we advance the // input. let at_next = self.input.at(at.next_pos()); - for i in 0..q.clist.size { - let pc = q.clist.pc(i); - let tcaps = q.clist.caps(i); - if self.step(&mut q.nlist, caps, tcaps, pc, at, at_next) { + for i in 0..clist.set.len() { + let ip = clist.set[i]; + let tcaps = clist.caps(ip); + if self.step(&mut nlist, caps, tcaps, ip, at, at_next) { matched = true; if caps.len() == 0 { // If we only care if a match occurs (not its @@ -130,27 +182,39 @@ impl<'r, 't> Nfa<'r, 't> { break; } } - if at.char().is_none() { + if at.is_end() { break; } at = at_next; - q.swap(); - q.nlist.empty(); + mem::swap(clist, nlist); + nlist.set.clear(); } matched } + /// Step through the input, one token (byte or codepoint) at a time. + /// + /// nlist is the set of states that will be processed on the next token + /// in the input. + /// + /// caps is the set of captures passed by the caller of the NFA. They are + /// written to only when a match state is visited. + /// + /// thread_caps is the set of captures set for the current NFA state, ip. + /// + /// at and at_next are the current and next positions in the input. at or + /// at_next may be EOF. fn step( - &self, + &mut self, nlist: &mut Threads, caps: &mut [Option], thread_caps: &mut [Option], - pc: usize, + ip: usize, at: InputAt, at_next: InputAt, ) -> bool { use inst::Inst::*; - match self.prog.insts[pc] { + match self.prog.insts[ip] { Match => { for (slot, val) in caps.iter_mut().zip(thread_caps.iter()) { *slot = *val; @@ -169,127 +233,117 @@ impl<'r, 't> Nfa<'r, 't> { } false } + Bytes(ref inst) => { + if let Some(b) = at.byte() { + if inst.matches(b) { + self.add(nlist, thread_caps, inst.goto, at_next); + } + } + false + } EmptyLook(_) | Save(_) | Split(_) => false, } } + /// Follows epsilon transitions and adds them for processing to nlist, + /// starting at and including ip. + /// + /// N.B. The inline(always) appears to increase throughput by about + /// 20% on micro-benchmarks. + #[inline(always)] fn add( - &self, + &mut self, nlist: &mut Threads, thread_caps: &mut [Option], - pc: usize, + ip: usize, at: InputAt, ) { - use inst::Inst::*; - - if nlist.contains(pc) { - return - } - let ti = nlist.add(pc); - match self.prog.insts[pc] { - EmptyLook(ref inst) => { - let prev = self.input.previous_at(at.pos()); - if inst.matches(prev.char(), at.char()) { - self.add(nlist, thread_caps, inst.goto, at); + self.stack.push(FollowEpsilon::IP(ip)); + while let Some(frame) = self.stack.pop() { + match frame { + FollowEpsilon::IP(ip) => { + self.add_step(nlist, thread_caps, ip, at); } - } - Save(ref inst) => { - if inst.slot >= thread_caps.len() { - self.add(nlist, thread_caps, inst.goto, at); - } else { - let old = thread_caps[inst.slot]; - thread_caps[inst.slot] = Some(at.pos()); - self.add(nlist, thread_caps, inst.goto, at); - thread_caps[inst.slot] = old; - } - } - Split(ref inst) => { - self.add(nlist, thread_caps, inst.goto1, at); - self.add(nlist, thread_caps, inst.goto2, at); - } - Match | Char(_) | Ranges(_) => { - let mut t = &mut nlist.thread(ti); - for (slot, val) in t.caps.iter_mut().zip(thread_caps.iter()) { - *slot = *val; + FollowEpsilon::Capture { slot, pos } => { + thread_caps[slot] = pos; } } } } -} - -/// Shared cached state between multiple invocations of a NFA engine -/// in the same thread. -/// -/// It is exported so that it can be cached by `program::Program`. -#[derive(Debug)] -pub struct NfaThreads { - clist: Threads, - nlist: Threads, -} - -#[derive(Debug)] -struct Threads { - dense: Vec, - sparse: Vec, - size: usize, -} -#[derive(Clone, Debug)] -struct Thread { - pc: usize, - caps: Vec>, -} - -impl NfaThreads { - /// Create new empty state for the NFA engine. - pub fn new(num_insts: usize, ncaps: usize) -> NfaThreads { - NfaThreads { - clist: Threads::new(num_insts, ncaps), - nlist: Threads::new(num_insts, ncaps), + /// A helper function for add that avoids excessive pushing to the stack. + fn add_step( + &mut self, + nlist: &mut Threads, + thread_caps: &mut [Option], + mut ip: usize, + at: InputAt, + ) { + // Instead of pushing and popping to the stack, we mutate ip as we + // traverse the set of states. We only push to the stack when we + // absolutely need recursion (restoring captures or following a + // branch). + use inst::Inst::*; + loop { + // Don't visit states we've already added. + if nlist.set.contains_ip(ip) { + return; + } + nlist.set.add(ip); + match self.prog.insts[ip] { + EmptyLook(ref inst) => { + let prev = self.input.previous_char(at); + let next = self.input.next_char(at); + if inst.matches(prev, next) { + ip = inst.goto; + } + } + Save(ref inst) => { + if inst.slot < thread_caps.len() { + self.stack.push(FollowEpsilon::Capture { + slot: inst.slot, + pos: thread_caps[inst.slot], + }); + thread_caps[inst.slot] = Some(at.pos()); + } + ip = inst.goto; + } + Split(ref inst) => { + self.stack.push(FollowEpsilon::IP(inst.goto2)); + ip = inst.goto1; + } + Match | Char(_) | Ranges(_) | Bytes(_) => { + let mut t = &mut nlist.caps(ip); + for (slot, val) in t.iter_mut().zip(thread_caps.iter()) { + *slot = *val; + } + return; + } + } } } - - fn swap(&mut self) { - ::std::mem::swap(&mut self.clist, &mut self.nlist); - } } impl Threads { - fn new(num_insts: usize, ncaps: usize) -> Threads { - let t = Thread { pc: 0, caps: vec![None; ncaps * 2] }; + fn new() -> Self { Threads { - dense: vec![t; num_insts], - sparse: vec![0; num_insts], - size: 0, + set: SparseSet::new(0), + caps: vec![], + slots_per_thread: 0, } } - fn add(&mut self, pc: usize) -> usize { - let i = self.size; - self.dense[i].pc = pc; - self.sparse[pc] = i; - self.size += 1; - i - } - - fn thread(&mut self, i: usize) -> &mut Thread { - &mut self.dense[i] - } - - fn contains(&self, pc: usize) -> bool { - let s = self.sparse[pc]; - s < self.size && self.dense[s].pc == pc - } - - fn empty(&mut self) { - self.size = 0; - } - - fn pc(&self, i: usize) -> usize { - self.dense[i].pc + fn resize(&mut self, num_insts: usize, ncaps: usize) { + if num_insts == self.set.capacity() { + return; + } + self.slots_per_thread = ncaps * 2; + self.set = SparseSet::new(num_insts); + self.caps = vec![None; self.slots_per_thread * num_insts]; } - fn caps(&mut self, i: usize) -> &mut [Option] { - &mut self.dense[i].caps + fn caps(&mut self, pc: usize) -> &mut [Option] { + let i = pc * self.slots_per_thread; + &mut self.caps[i..i + self.slots_per_thread] } } diff --git a/src/prefix.rs b/src/prefix.rs deleted file mode 100644 index 92d7366e2c..0000000000 --- a/src/prefix.rs +++ /dev/null @@ -1,243 +0,0 @@ -// Copyright 2014-2015 The Rust Project Developers. See the COPYRIGHT -// file at the top-level directory of this distribution and at -// http://rust-lang.org/COPYRIGHT. -// -// Licensed under the Apache License, Version 2.0 or the MIT license -// , at your -// option. This file may not be copied, modified, or distributed -// except according to those terms. - -use std::fmt; - -use aho_corasick::{Automaton, AcAutomaton, FullAcAutomaton}; -use memchr::memchr; - -/// A prefix extracted from a compiled regular expression. -/// -/// A regex prefix is a set of literal strings that *must* be matched at the -/// beginning of a regex in order for the entire regex to match. -/// -/// There are a variety of ways to efficiently scan the search text for a -/// prefix. Currently, there are three implemented: -/// -/// 1. The prefix is a single byte. Just use memchr. -/// 2. If the prefix is a set of two or more single byte prefixes, then -/// a single sparse map is created. Checking if there is a match is a lookup -/// in this map for each byte in the search text. -/// 3. In all other cases, build an Aho-Corasick automaton. -/// -/// It's possible that there's room here for other substring algorithms, -/// such as Boyer-Moore for single-set prefixes greater than 1, or Rabin-Karp -/// for small sets of same-length prefixes. -#[derive(Clone)] -pub enum Prefix { - /// No prefixes. (Never advances through the input.) - Empty, - /// A single byte prefix. - Byte(u8), - /// A set of two or more single byte prefixes. - /// This could be reduced to a bitset, which would use only 8 bytes, - /// but I don't think we care. - Bytes { - chars: Vec, - sparse: Vec, - }, - Single(SingleSearch), - /// A full Aho-Corasick DFA automaton. - Automaton(FullAcAutomaton), -} - -impl Prefix { - /// Create a new prefix matching machine. - pub fn new(mut pfxs: Vec) -> Prefix { - if pfxs.is_empty() || pfxs[0].is_empty() { - Prefix::Empty - } else if pfxs.len() == 1 && pfxs[0].len() == 1 { - Prefix::Byte(pfxs[0].as_bytes()[0]) - } else if pfxs.len() >= 2 && pfxs.iter().all(|s| s.len() == 1) { - let mut set = vec![false; 256]; - let mut chars = vec![]; - for p in pfxs { - chars.push(p.as_bytes()[0]); - set[p.as_bytes()[0] as usize] = true; - } - Prefix::Bytes { chars: chars, sparse: set } - } else if pfxs.len() == 1 { - Prefix::Single(SingleSearch::new(pfxs.pop().unwrap())) - } else { - Prefix::Automaton(AcAutomaton::new(pfxs).into_full()) - } - } - - /// Find the position of a prefix in `haystack` if it exists. - /// - /// In the matching engines, we only actually need the starting index - /// because the prefix is used to only skip ahead---the matching engine - /// still needs to run over the prefix input. However, we return the ending - /// location as well in case the prefix corresponds to the entire regex, - /// in which case, you need the end of the match. - pub fn find(&self, haystack: &str) -> Option<(usize, usize)> { - use self::Prefix::*; - match *self { - Empty => Some((0, 0)), - Byte(b) => memchr(b, haystack.as_bytes()).map(|i| (i, i+1)), - Bytes { ref sparse, .. } => { - find_singles(sparse, haystack.as_bytes()) - } - Single(ref searcher) => { - searcher.find(haystack).map(|i| (i, i + searcher.pat.len())) - } - Automaton(ref aut) => { - aut.find(haystack).next().map(|m| (m.start, m.end)) - } - } - } - - /// Returns true iff this prefix is empty. - pub fn is_empty(&self) -> bool { - self.len() == 0 - } - - /// Returns the number of prefixes in this machine. - pub fn len(&self) -> usize { - match *self { - Prefix::Empty => 0, - Prefix::Byte(_) => 1, - Prefix::Bytes { ref chars, .. } => chars.len(), - Prefix::Single(_) => 1, - Prefix::Automaton(ref aut) => aut.len(), - } - } - - /// Returns true iff the prefix match preserves priority. - /// - /// For example, given the alternation `ab|a` and the target string `ab`, - /// does the prefix machine guarantee that `ab` will match? (A full - /// Aho-Corasick automaton does not!) - pub fn preserves_priority(&self) -> bool { - match *self { - Prefix::Empty => true, - Prefix::Byte(_) => true, - Prefix::Bytes{..} => true, - Prefix::Single(_) => true, - Prefix::Automaton(ref aut) => { - // Okay, so the automaton can respect priority in one - // particular case: when every pattern is of the same length. - // The trick is that the automaton will report the leftmost - // match, which in this case, corresponds to the correct - // match for the regex engine. If any other alternate matches - // at the same position, then they must be exactly equivalent. - - // Guaranteed at least one prefix by construction, so use - // that for the length. - aut.patterns().iter().all(|p| p.len() == aut.pattern(0).len()) - } - } - } - - /// Returns all of the prefixes participating in this machine. - /// - /// For debug/testing only! (It allocates.) - #[allow(dead_code)] - pub fn prefixes(&self) -> Vec { - match *self { - Prefix::Empty => vec![], - Prefix::Byte(b) => vec![format!("{}", b as char)], - Prefix::Bytes { ref chars, .. } => { - chars.iter().map(|&b| format!("{}", b as char)).collect() - } - Prefix::Single(ref searcher) => vec![searcher.pat.clone()], - Prefix::Automaton(ref aut) => aut.patterns().to_vec(), - } - } -} - -/// Provides an implementation of fast subtring search. -/// -/// In particular, this uses Boyer-Moore-Horspool with Tim Raita's twist: -/// https://en.wikipedia.org/wiki/Raita_Algorithm -/// -/// I'm skeptical of the utility here, because benchmarks suggest that it is -/// difficult to beat Aho-Corasick on random text. Namely, both algorithms are -/// dominated by the performance of `memchr` for the leading byte prefix. -/// With that said, BMH does seem to surpass AC when the search text gets -/// longer (see the `easy0_1MB` vs. `easy1_1MB` benchmarks). -/// -/// More analysis needs to be done to test this on different search texts. -#[derive(Clone, Debug)] -pub struct SingleSearch { - pat: String, - shift: Vec, -} - -impl SingleSearch { - fn new(pat: String) -> SingleSearch { - assert!(pat.len() >= 1); - let mut shift = vec![pat.len(); 256]; - for i in 0..(pat.len() - 1) { - shift[pat.as_bytes()[i] as usize] = pat.len() - i - 1; - } - SingleSearch { - pat: pat, - shift: shift, - } - } - - fn find(&self, haystack: &str) -> Option { - let pat = self.pat.as_bytes(); - let haystack = haystack.as_bytes(); - if haystack.len() < pat.len() { - return None; - } - let mut i = match memchr(pat[0], haystack) { - None => return None, - Some(i) => i, - }; - while i <= haystack.len() - pat.len() { - let b = haystack[i + pat.len() - 1]; - if b == pat[pat.len() - 1] - && haystack[i] == pat[0] - && haystack[i + (pat.len() / 2)] == pat[pat.len() / 2] - && pat == &haystack[i..i + pat.len()] { - return Some(i); - } - i += self.shift[b as usize]; - i += match memchr(pat[0], &haystack[i..]) { - None => return None, - Some(i) => i, - }; - } - None - } -} - -/// A quick scan for multiple single byte prefixes using a sparse map. -fn find_singles(sparse: &[bool], haystack: &[u8]) -> Option<(usize, usize)> { - // TODO: Improve this with ideas found in jetscii crate. - for (hi, &b) in haystack.iter().enumerate() { - if sparse[b as usize] { - return Some((hi, hi+1)); - } - } - None -} - -impl fmt::Debug for Prefix { - #[allow(deprecated)] // connect => join in 1.3 - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - match *self { - Prefix::Empty => write!(f, "Empty"), - Prefix::Byte(b) => write!(f, "{:?}", b as char), - Prefix::Bytes { ref chars, .. } => { - let chars: Vec = - chars.iter() - .map(|&c| format!("{:?}", c as char)) - .collect(); - write!(f, "{}", chars.connect(", ")) - } - Prefix::Single(ref searcher) => write!(f, "{:?}", searcher), - Prefix::Automaton(ref aut) => write!(f, "{:?}", aut), - } - } -} diff --git a/src/program.rs b/src/program.rs index ad6c2a261c..f4be4aaf70 100644 --- a/src/program.rs +++ b/src/program.rs @@ -10,428 +10,204 @@ use syntax; +use backtrack::BacktrackCache; +use compile::{Compiled, Compiler}; +use dfa::DfaCache; +use inst::Insts; +use nfa::NfaCache; +use pool::{Pool, PoolGuard}; +use literals::Literals; use Error; -use backtrack::{Backtrack, BackMachine}; -use compile::Compiler; -use inst::{EmptyLook, Inst}; -use nfa::{Nfa, NfaThreads}; -use pool::Pool; -use prefix::Prefix; -use re::CaptureIdxs; -const NUM_PREFIX_LIMIT: usize = 30; -const PREFIX_LENGTH_LIMIT: usize = 15; - -/// The matching engines offered by this regex implementation. -/// -/// N.B. This is exported for use in testing. -#[doc(hidden)] -#[derive(Clone, Copy, Debug)] -pub enum MatchEngine { - /// A bounded backtracking implementation. About twice as fast as the - /// NFA, but can only work on small regexes and small input. - Backtrack, - /// A full NFA simulation. Can always be employed but almost always the - /// slowest choice. - Nfa, - /// If the entire regex is a literal and no capture groups have been - /// requested, then we can degrade to a simple substring match. - Literals, -} /// Program represents a compiled regular expression. Once an expression is /// compiled, its representation is immutable and will never change. /// (Well, almost. In fact, the matching engines cache state that can be /// reused on subsequent searches. But this is interior mutability that /// shouldn't be observable by the caller.) -#[derive(Debug)] +/// +/// A compiled regular expression contains quite a bit more than justs its +/// opcodes. It also contains capture group names, literal prefixes, the +/// original regular expression string and some facts about the expression +/// (like whether it is anchored to the beginning or end of the search text). +#[derive(Clone, Debug)] pub struct Program { /// The original regular expression string. pub original: String, /// A sequence of instructions. - pub insts: Vec, + pub insts: Insts, /// The sequence of capture group names. There is an entry for each capture /// group index and a name exists only if the capture group is named. pub cap_names: Vec>, /// If the regular expression requires a literal prefix in order to have a /// match, that prefix is stored here as a DFA. - pub prefixes: Prefix, - /// True iff matching any literal prefix indicates a match. - pub prefixes_complete: bool, + pub prefixes: Literals, /// True iff program is anchored at the beginning. pub anchored_begin: bool, /// True iff program is anchored at the end. pub anchored_end: bool, - /// The type of matching engine to use. - /// When `None` (the default), pick an engine automatically. - pub engine: Option, - /// Cached NFA threads. - pub nfa_threads: Pool, - /// Cached backtracking memory. - pub backtrack: Pool, + /// Cached reusable state for matching engines. + pub cache: EngineCache, } -impl Program { - /// Compiles a Regex. - pub fn new( - engine: Option, - size_limit: usize, - re: &str, - ) -> Result { - let expr = try!(syntax::Expr::parse(re)); - let compiler = Compiler::new(size_limit); - let (insts, cap_names) = try!(compiler.compile(&expr)); - let (insts_len, ncaps) = (insts.len(), num_captures(&insts)); - let create_threads = move || NfaThreads::new(insts_len, ncaps); - let create_backtrack = move || BackMachine::new(); - let mut prog = Program { - original: re.into(), - insts: insts, - cap_names: cap_names, - prefixes: Prefix::Empty, - prefixes_complete: false, - anchored_begin: false, - anchored_end: false, - engine: engine, - nfa_threads: Pool::new(Box::new(create_threads)), - backtrack: Pool::new(Box::new(create_backtrack)), - }; - - prog.find_prefixes(); - prog.anchored_begin = match prog.insts[1] { - Inst::EmptyLook(ref inst) => inst.look == EmptyLook::StartText, - _ => false, - }; - prog.anchored_end = match prog.insts[prog.insts.len() - 3] { - Inst::EmptyLook(ref inst) => inst.look == EmptyLook::EndText, - _ => false, - }; - Ok(prog) - } +/// A builder for compiling a regular expression program. +pub struct ProgramBuilder { + re: String, + compiler: Compiler, +} - /// Executes a compiled regex program. - pub fn exec( - &self, - caps: &mut CaptureIdxs, - text: &str, - start: usize, - ) -> bool { - match self.choose_engine(caps.len(), text) { - MatchEngine::Backtrack => Backtrack::exec(self, caps, text, start), - MatchEngine::Nfa => Nfa::exec(self, caps, text, start), - MatchEngine::Literals => { - match self.prefixes.find(&text[start..]) { - None => false, - Some((s, e)) => { - if caps.len() == 2 { - caps[0] = Some(start + s); - caps[1] = Some(start + e); - } - true - } - } - } +impl ProgramBuilder { + /// Create a new program builder for the given regular expression. + /// + /// Afer new is called, it is legal to call compile immediately. Default + /// values for other knobs are set automatically. + pub fn new(re: &str) -> Self { + ProgramBuilder { + re: re.to_owned(), + compiler: Compiler::new(), } } - fn choose_engine(&self, cap_len: usize, text: &str) -> MatchEngine { - // If the engine is already chosen, then we use it. - // But that might not be a good idea. e.g., What if `Literals` is - // chosen and it can't work? I guess we should probably check whether - // the chosen engine is appropriate or not. - self.engine.unwrap_or_else(|| { - if cap_len <= 2 - && self.prefixes_complete - && self.prefixes.preserves_priority() { - MatchEngine::Literals - } else if Backtrack::should_exec(self, text) { - // We're only here if the input and regex combined are small. - MatchEngine::Backtrack - } else { - MatchEngine::Nfa - } - }) - } - - /// Returns the total number of capture groups in the regular expression. - /// This includes the zeroth capture. - pub fn num_captures(&self) -> usize { - num_captures(&self.insts) - } - - /// Allocate new capture groups. - pub fn alloc_captures(&self) -> Vec> { - vec![None; 2 * self.num_captures()] + /// Set a size limit that the compiler uses to limit the total number of + /// bytes occupied by the opcodes for this regex. + pub fn size_limit(mut self, size_limit: usize) -> Self { + self.compiler = self.compiler.size_limit(size_limit); + self } - /// Find and store a prefix machine for the current program. - pub fn find_prefixes(&mut self) { - // First, look for a standard literal prefix---this includes things - // like `a+` and `[0-9]+`, but not `a|b`. - let (ps, complete) = self.literals(self.skip(1)); - if !ps.is_empty() { - self.prefixes = Prefix::new(ps); - self.prefixes_complete = complete; - return; - } - // Ok, now look for alternate prefixes, e.g., `a|b`. - if let Some((pfxs, complete)) = self.alternate_prefixes() { - self.prefixes = Prefix::new(pfxs); - self.prefixes_complete = complete; - } - } - - fn alternate_prefixes(&self) -> Option<(Vec, bool)> { - let mut prefixes = vec![]; - let mut pcomplete = true; - let mut stack = vec![self.skip(1)]; - while let Some(mut pc) = stack.pop() { - pc = self.skip(pc); - match self.insts[pc] { - Inst::Split(ref inst) => { - stack.push(inst.goto2); - stack.push(inst.goto1); - } - _ => { - let (alt_prefixes, complete) = self.literals(pc); - if alt_prefixes.is_empty() { - // If no prefixes could be identified for this - // alternate, then we can't use a prefix machine to - // skip through the input. Thus, we fail and report - // nothing. - return None; - } - if prefixes.len() + alt_prefixes.len() > NUM_PREFIX_LIMIT { - // Arg. We've over-extended ourselves, quit with - // nothing to show for it. - // - // This could happen if the regex is `a|b|c|...`, where - // the number of alternates is too much for us to - // handle given an empirically defined threshold limit. - // - // When this happens, we can't capture all of the - // prefixes, so our prefix machine becomes useless. - // Thus, fail and report nothing. - return None; - } - pcomplete = pcomplete && complete; - prefixes.extend(alt_prefixes); - } - } - } - if prefixes.is_empty() { - None - } else { - Some((prefixes, pcomplete)) - } + /// Enable compilation of a byte based program. + /// + /// By default, programs operate on Unicode codepoints. + pub fn bytes(mut self, yes: bool) -> Self { + self.compiler = self.compiler.bytes(yes); + self } - /// Find required literals starting at the given instruction. + /// Enable compilation of a byte based DFA program. /// - /// Returns `true` in the tuple if the end of the literal leads trivially - /// to a match. (This may report false negatives, but being conservative - /// is OK.) - fn literals(&self, mut pc: usize) -> (Vec, bool) { - #![allow(unused_assignments)] - use inst::Inst::*; - - let mut complete = true; - let mut alts = vec![String::new()]; - loop { - let inst = &self.insts[pc]; - - // Each iteration adds one character to every alternate prefix *or* - // it stops. Thus, the prefix alternates grow in lock step, and it - // suffices to check one of them to see if the prefix limit has - // been exceeded. - if alts[0].len() > PREFIX_LENGTH_LIMIT { - complete = false; - break; - } - match *inst { - Save(ref inst) => { pc = inst.goto; continue } - Char(ref inst) => { - for alt in &mut alts { - alt.push(inst.c); - } - pc = inst.goto; - } - Ranges(ref inst) => { - // This adds a new literal for *each* character in this - // range. This has the potential to use way too much - // memory, so we bound it naively for now. - let nchars = num_chars_in_ranges(&inst.ranges); - if alts.len() * nchars > NUM_PREFIX_LIMIT { - complete = false; - break; - } - - let orig = alts; - alts = Vec::with_capacity(orig.len()); - for &(s, e) in &inst.ranges { - for c in (s as u32)..(e as u32 + 1){ - for alt in &orig { - let mut alt = alt.clone(); - alt.push(::std::char::from_u32(c).unwrap()); - alts.push(alt); - } - } - } - pc = inst.goto; - } - _ => { complete = self.leads_to_match(pc); break } - } - } - if alts[0].is_empty() { - (vec![], false) - } else { - (alts, complete) - } + /// This does instruct the compiler to compile a byte based program, but + /// it also does other things that are specifically required by the lazy + /// DFA, such as adding a `.*?` before the first capture save for + /// unanchored regular expressions. + pub fn dfa(mut self, yes: bool) -> Self { + self.compiler = self.compiler.dfa(yes); + self } - fn leads_to_match(&self, pc: usize) -> bool { - // I'm pretty sure this is conservative, so it might have some - // false negatives. - match self.insts[self.skip(pc)] { - Inst::Match => true, - _ => false, - } + /// Compile the regular expression in reverse. + /// + /// This is generally only used by the lazy DFA to find the start location + /// of a match. + pub fn reverse(mut self, yes: bool) -> Self { + self.compiler = self.compiler.reverse(yes); + self } - fn skip(&self, mut pc: usize) -> usize { - loop { - match self.insts[pc] { - Inst::Save(_) => pc += 1, - _ => return pc, - } - } + /// Compile the given regular expression under the given configuration. + /// + /// If the regular expression could not be compiled (e.g., it is too big), + /// then return an error. + pub fn compile(self) -> Result { + let expr = try!(syntax::Expr::parse(&self.re)); + let Compiled { insts, cap_names } = try!(self.compiler.compile(&expr)); + let (prefixes, anchored_begin, anchored_end) = ( + insts.prefix_matcher(), + insts.anchored_begin(), + insts.anchored_end(), + ); + Ok(Program { + original: self.re, + insts: insts, + cap_names: cap_names, + prefixes: prefixes, + anchored_begin: anchored_begin, + anchored_end: anchored_end, + cache: EngineCache::new(), + }) } } -impl Clone for Program { - fn clone(&self) -> Program { - let (insts_len, ncaps) = (self.insts.len(), self.num_captures()); - let create_threads = move || NfaThreads::new(insts_len, ncaps); - let create_backtrack = move || BackMachine::new(); - Program { - original: self.original.clone(), - insts: self.insts.clone(), - cap_names: self.cap_names.clone(), - prefixes: self.prefixes.clone(), - prefixes_complete: self.prefixes_complete, - anchored_begin: self.anchored_begin, - anchored_end: self.anchored_end, - engine: self.engine, - nfa_threads: Pool::new(Box::new(create_threads)), - backtrack: Pool::new(Box::new(create_backtrack)), - } +impl Program { + /// Returns true if the set of literal prefixes implies a match and + /// preserves leftmost first matching semantics. + /// + /// If this returns true, then it is possible to avoid running any of the + /// NFA or DFA based matching engines entirely. + pub fn is_prefix_match(&self) -> bool { + self.prefixes.at_match() && self.prefixes.preserves_priority() } -} -/// Return the number of captures in the given sequence of instructions. -fn num_captures(insts: &[Inst]) -> usize { - let mut n = 0; - for inst in insts { - if let Inst::Save(ref inst) = *inst { - n = ::std::cmp::max(n, inst.slot + 1) - } + /// Returns true if the underlying program is reversed. + pub fn is_reversed(&self) -> bool { + self.insts.is_reversed() } - // There's exactly 2 Save slots for every capture. - n / 2 -} - -/// Count the number of characters in the given range. -/// -/// This is useful for pre-emptively limiting the number of prefix literals -/// we extract from a regex program. -fn num_chars_in_ranges(ranges: &[(char, char)]) -> usize { - ranges.iter() - .map(|&(s, e)| 1 + (e as u32) - (s as u32)) - .fold(0, |acc, len| acc + len) as usize -} -#[cfg(test)] -mod tests { - use super::Program; - - macro_rules! prog { - ($re:expr) => { Program::new(None, 1 << 30, $re).unwrap() } + /// Returns the total number of capture groups in the regular expression. + /// This includes the zeroth capture. + pub fn num_captures(&self) -> usize { + self.cap_names.len() } - macro_rules! prefixes { - ($re:expr) => {{ - let p = prog!($re); - assert!(!p.prefixes_complete); - p.prefixes.prefixes() - }} - } - macro_rules! prefixes_complete { - ($re:expr) => {{ - let p = prog!($re); - assert!(p.prefixes_complete); - p.prefixes.prefixes() - }} + /// Allocate new capture groups. + pub fn alloc_captures(&self) -> Vec> { + vec![None; 2 * self.num_captures()] } - #[test] - fn single() { - assert_eq!(prefixes_complete!("a"), vec!["a"]); - assert_eq!(prefixes_complete!("[a]"), vec!["a"]); - assert_eq!(prefixes!("a+"), vec!["a"]); - assert_eq!(prefixes!("(?:a)+"), vec!["a"]); - assert_eq!(prefixes!("(a)+"), vec!["a"]); + /// Retrieve cached state for NFA execution. + pub fn cache_nfa(&self) -> PoolGuard> { + self.cache.nfa.get() } - #[test] - fn single_alt() { - assert_eq!(prefixes_complete!("a|b"), vec!["a", "b"]); - assert_eq!(prefixes_complete!("b|a"), vec!["b", "a"]); - assert_eq!(prefixes_complete!("[a]|[b]"), vec!["a", "b"]); - assert_eq!(prefixes!("a+|b"), vec!["a", "b"]); - assert_eq!(prefixes!("a|b+"), vec!["a", "b"]); - assert_eq!(prefixes!("(?:a+)|b"), vec!["a", "b"]); - assert_eq!(prefixes!("(a+)|b"), vec!["a", "b"]); + /// Retrieve cached state for backtracking execution. + pub fn cache_backtrack(&self) -> PoolGuard> { + self.cache.backtrack.get() } - #[test] - fn many() { - assert_eq!(prefixes_complete!("abcdef"), vec!["abcdef"]); - assert_eq!(prefixes!("abcdef+"), vec!["abcdef"]); - assert_eq!(prefixes!("(?:abcdef)+"), vec!["abcdef"]); - assert_eq!(prefixes!("(abcdef)+"), vec!["abcdef"]); + /// Retrieve cached state for DFA execution. + pub fn cache_dfa(&self) -> PoolGuard> { + self.cache.dfa.get() } - #[test] - fn many_alt() { - assert_eq!(prefixes_complete!("abc|def"), vec!["abc", "def"]); - assert_eq!(prefixes_complete!("def|abc"), vec!["def", "abc"]); - assert_eq!(prefixes!("abc+|def"), vec!["abc", "def"]); - assert_eq!(prefixes!("abc|def+"), vec!["abc", "def"]); - assert_eq!(prefixes!("(?:abc)+|def"), vec!["abc", "def"]); - assert_eq!(prefixes!("(abc)+|def"), vec!["abc", "def"]); + /// Return the approximate heap usage of this Program in bytes. + /// + /// Note that this does not include cached engine data. + pub fn approximate_size(&self) -> usize { + // ignore capture names + self.original.len() + + self.insts.approximate_size() + + self.prefixes.approximate_size() } +} - #[test] - fn class() { - assert_eq!(prefixes_complete!("[0-9]"), vec![ - "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", - ]); - assert_eq!(prefixes!("[0-9]+"), vec![ - "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", - ]); - } +/// EngineCache maintains reusable allocations for each matching engine +/// available to a particular program. +/// +/// The allocations are created lazily, so we don't pay for caches that +/// aren't used. +/// +/// N.B. These are all behind a pointer because it's fewer bytes to memcpy. +/// These caches are pushed/popped from the pool a lot, and a smaller +/// footprint can have an impact on matching small inputs. See, for example, +/// the hard_32 benchmark. +#[derive(Debug)] +pub struct EngineCache { + nfa: Pool>, + backtrack: Pool>, + dfa: Pool>, +} - #[test] - fn preceding_alt() { - assert_eq!(prefixes!("(?:a|b).+"), vec!["a", "b"]); - assert_eq!(prefixes!("(a|b).+"), vec!["a", "b"]); +impl EngineCache { + fn new() -> Self { + EngineCache { + nfa: Pool::new(Box::new(|| Box::new(NfaCache::new()))), + backtrack: Pool::new(Box::new(|| Box::new(BacktrackCache::new()))), + dfa: Pool::new(Box::new(|| Box::new(DfaCache::new()))), + } } +} - #[test] - fn nested_alt() { - assert_eq!(prefixes_complete!("(a|b|c|d)"), - vec!["a", "b", "c", "d"]); - assert_eq!(prefixes_complete!("((a|b)|(c|d))"), - vec!["a", "b", "c", "d"]); +impl Clone for EngineCache { + fn clone(&self) -> EngineCache { + EngineCache::new() } } diff --git a/src/re.rs b/src/re.rs index 1d59deafed..43185abe28 100644 --- a/src/re.rs +++ b/src/re.rs @@ -17,7 +17,7 @@ use std::ops::Index; use std::str::pattern::{Pattern, Searcher, SearchStep}; use std::str::FromStr; -use program::{Program, MatchEngine}; +use exec::{Exec, ExecBuilder}; use syntax; const REPLACE_EXPAND: &'static str = r"(?x) @@ -174,7 +174,7 @@ pub enum Regex { // See the comments for the `program` module in `lib.rs` for a more // detailed explanation for what `regex!` requires. #[doc(hidden)] - Dynamic(Program), + Dynamic(Exec), #[doc(hidden)] Native(ExNative), } @@ -249,29 +249,7 @@ impl Regex { /// /// The default size limit used in `new` is 10MB. pub fn with_size_limit(size: usize, re: &str) -> Result { - Regex::with_engine(None, size, re) - } - - /// Compiles a dynamic regular expression and uses given matching engine. - /// - /// This is exposed for use in testing and shouldn't be used by clients. - /// Instead, the regex program should choose the correct matching engine - /// to use automatically. (Based on the regex, the size of the input and - /// the type of search.) - /// - /// A value of `None` means that the engine is automatically selected, - /// which is the default behavior. - /// - /// **WARNING**: Passing an unsuitable engine for the given regex/input - /// could lead to bad things. (Not unsafe things, but panics, incorrect - /// matches and large memory use are all things that could happen.) - #[doc(hidden)] - pub fn with_engine( - engine: Option, - size: usize, - re: &str, - ) -> Result { - Program::new(engine, size, re).map(Regex::Dynamic) + ExecBuilder::new(re).size_limit(size).build().map(Regex::Dynamic) } @@ -350,7 +328,7 @@ impl Regex { re: self, search: text, last_end: 0, - skip_next_empty: false + last_match: None, } } @@ -455,7 +433,7 @@ impl Regex { re: self, search: text, last_end: 0, - skip_next_empty: false + last_match: None, } } @@ -604,13 +582,19 @@ impl Regex { /// submatches in the replacement string. pub fn replacen (&self, text: &str, limit: usize, mut rep: R) -> String { - let mut new = String::with_capacity(text.len()); - let mut last_match = 0; - if rep.no_expand().is_some() { - // borrow checker pains. `rep` is borrowed mutably in the `else` - // branch below. - let rep = rep.no_expand().unwrap(); + // If we know that the replacement doesn't have any capture expansions, + // then we can fast path. The fast path can make a tremendous + // difference: + // + // 1) We use `find_iter` instead of `captures_iter`. Not asking for + // captures generally makes the regex engines faster. + // 2) We don't need to look up all of the capture groups and do + // replacements inside the replacement string. We just push it + // at each match and be done with it. + if let Some(rep) = rep.no_expand() { + let mut new = String::with_capacity(text.len()); + let mut last_match = 0; for (i, (s, e)) in self.find_iter(text).enumerate() { if limit > 0 && i >= limit { break @@ -619,17 +603,23 @@ impl Regex { new.push_str(&rep); last_match = e; } - } else { - for (i, cap) in self.captures_iter(text).enumerate() { - if limit > 0 && i >= limit { - break - } - // unwrap on 0 is OK because captures only reports matches - let (s, e) = cap.pos(0).unwrap(); - new.push_str(&text[last_match..s]); - new.push_str(&rep.reg_replace(&cap)); - last_match = e; + new.push_str(&text[last_match..]); + return new; + } + + // The slower path, which we use if the replacement needs access to + // capture groups. + let mut new = String::with_capacity(text.len()); + let mut last_match = 0; + for (i, cap) in self.captures_iter(text).enumerate() { + if limit > 0 && i >= limit { + break } + // unwrap on 0 is OK because captures only reports matches + let (s, e) = cap.pos(0).unwrap(); + new.push_str(&text[last_match..s]); + new.push_str(&rep.reg_replace(&cap)); + last_match = e; } new.push_str(&text[last_match..]); new @@ -638,7 +628,7 @@ impl Regex { /// Returns the original string of this regex. pub fn as_str(&self) -> &str { match *self { - Regex::Dynamic(Program { ref original, .. }) => original, + Regex::Dynamic(ref exec) => exec.regex_str(), Regex::Native(ExNative { ref original, .. }) => original, } } @@ -647,7 +637,9 @@ impl Regex { pub fn capture_names(&self) -> CaptureNames { match *self { Regex::Native(ref n) => CaptureNames::Native(n.names.iter()), - Regex::Dynamic(ref d) => CaptureNames::Dynamic(d.cap_names.iter()) + Regex::Dynamic(ref d) => { + CaptureNames::Dynamic(d.capture_names().iter()) + } } } @@ -655,7 +647,7 @@ impl Regex { pub fn captures_len(&self) -> usize { match *self { Regex::Native(ref n) => n.names.len(), - Regex::Dynamic(ref d) => d.cap_names.len() + Regex::Dynamic(ref d) => d.capture_names().len() } } @@ -910,7 +902,10 @@ impl<'t> Captures<'t> { /// name and the value. The iterator returns these values in arbitrary /// order. pub fn iter_named(&'t self) -> SubCapturesNamed<'t> { - SubCapturesNamed { caps: self, inner: self.named.as_ref().map(|n| n.iter()) } + SubCapturesNamed { + caps: self, + inner: self.named.as_ref().map(|n| n.iter()), + } } /// Expands all instances of `$name` in `text` to the corresponding capture @@ -1057,7 +1052,7 @@ pub struct FindCaptures<'r, 't> { re: &'r Regex, search: &'t str, last_end: usize, - skip_next_empty: bool + last_match: Option, } impl<'r, 't> Iterator for FindCaptures<'r, 't> { @@ -1076,17 +1071,16 @@ impl<'r, 't> Iterator for FindCaptures<'r, 't> { // Don't accept empty matches immediately following a match. // i.e., no infinite loops please. - if e == s { - self.last_end += self.search[self.last_end..].chars() - .next().map(|c| c.len_utf8()).unwrap_or(1); - if self.skip_next_empty { - self.skip_next_empty = false; - return self.next(); + if e == s && Some(self.last_end) == self.last_match { + if self.last_end >= self.search.len() { + return None; } - } else { - self.last_end = e; - self.skip_next_empty = true; + self.last_end += self.search[self.last_end..].chars() + .next().unwrap().len_utf8(); + return self.next(); } + self.last_end = e; + self.last_match = Some(self.last_end); Some(Captures::new(self.re, self.search, caps)) } } @@ -1103,7 +1097,7 @@ pub struct FindMatches<'r, 't> { re: &'r Regex, search: &'t str, last_end: usize, - skip_next_empty: bool + last_match: Option, } impl<'r, 't> Iterator for FindMatches<'r, 't> { @@ -1122,17 +1116,16 @@ impl<'r, 't> Iterator for FindMatches<'r, 't> { // Don't accept empty matches immediately following a match. // i.e., no infinite loops please. - if e == s { - self.last_end += self.search[self.last_end..].chars() - .next().map(|c| c.len_utf8()).unwrap_or(1); - if self.skip_next_empty { - self.skip_next_empty = false; - return self.next(); + if e == s && Some(self.last_end) == self.last_match { + if self.last_end >= self.search.len() { + return None; } - } else { - self.last_end = e; - self.skip_next_empty = true; + self.last_end += self.search[self.last_end..].chars() + .next().unwrap().len_utf8(); + return self.next(); } + self.last_end = e; + self.last_match = Some(self.last_end); Some((s, e)) } } diff --git a/src/sparse.rs b/src/sparse.rs new file mode 100644 index 0000000000..8f5bd9d5b6 --- /dev/null +++ b/src/sparse.rs @@ -0,0 +1,82 @@ +use std::ops::Deref; +use std::slice; + +/// A sparse set used for representing ordered NFA states. +/// +/// This supports constant time addition and membership testing. Clearing an +/// entire set can also be done in constant time. Iteration yields elements +/// in the order in which they were inserted. +/// +/// The data structure is based on: http://research.swtch.com/sparse +/// Note though that we don't actually use unitialized memory. We generally +/// reuse allocations, so the initial allocation cost is bareable. However, +/// its other properties listed above are extremely useful. +/// +/// N.B. The type parameter is misleading. For the most part, this is only +/// meant to work on instruction pointers. We use a touch of generics to +/// support 32 bit instruction pointers. +#[derive(Debug)] +pub struct SparseSet { + /// Dense contains the instruction pointers in the order in which they + /// were inserted. Accessing elements >= self.size is illegal. + dense: Vec, + /// Sparse maps instruction pointers to their location in dense. + /// + /// An instruction pointer is in the set if and only if + /// sparse[ip] < size && ip == dense[sparse[ip]]. + sparse: Vec, + /// The number of elements in the set. + size: usize, +} + +impl SparseSet { + pub fn new(size: usize) -> SparseSet { + SparseSet { + dense: vec![0; size], + sparse: vec![0; size], + size: 0, + } + } + + pub fn len(&self) -> usize { + self.size + } + + pub fn is_empty(&self) -> bool { + self.size == 0 + } + + pub fn capacity(&self) -> usize { + self.dense.len() + } + + pub fn add(&mut self, ip: usize) { + let i = self.size; + self.dense[i] = ip; + self.sparse[ip] = i; + self.size += 1; + } + + pub fn contains_ip(&self, ip: usize) -> bool { + let i = self.sparse[ip]; + i < self.size && self.dense[i] == ip + } + + pub fn clear(&mut self) { + self.size = 0; + } +} + +impl Deref for SparseSet { + type Target = [usize]; + + fn deref(&self) -> &Self::Target { + &self.dense[0..self.size] + } +} + +impl<'a> IntoIterator for &'a SparseSet { + type Item = &'a usize; + type IntoIter = slice::Iter<'a, usize>; + fn into_iter(self) -> Self::IntoIter { self.iter() } +} diff --git a/regex_macros/tests/matches.rs b/tests/matches.rs similarity index 100% rename from regex_macros/tests/matches.rs rename to tests/matches.rs diff --git a/regex_macros/tests/native_static.rs b/tests/native_static.rs similarity index 100% rename from regex_macros/tests/native_static.rs rename to tests/native_static.rs diff --git a/regex_macros/tests/test_dynamic.rs b/tests/test_dynamic.rs similarity index 91% rename from regex_macros/tests/test_dynamic.rs rename to tests/test_dynamic.rs index a95cc71586..98837d70dd 100644 --- a/regex_macros/tests/test_dynamic.rs +++ b/tests/test_dynamic.rs @@ -20,9 +20,10 @@ extern crate regex; // the normal code path which automatically chooses the engine based on the // regex and the input. Other dynamic tests explicitly set the engine to use. macro_rules! regex { - ($re:expr) => { - ::regex::Regex::with_engine(None, 10 * (1 << 20), $re).unwrap() - } + ($re:expr) => {{ + use regex::internal::ExecBuilder; + ExecBuilder::new($re).build().unwrap().into_regex() + }} } #[cfg(feature = "pattern")] diff --git a/regex_macros/tests/test_dynamic_backtrack.rs b/tests/test_dynamic_backtrack.rs similarity index 84% rename from regex_macros/tests/test_dynamic_backtrack.rs rename to tests/test_dynamic_backtrack.rs index c386321101..76b14829c3 100644 --- a/regex_macros/tests/test_dynamic_backtrack.rs +++ b/tests/test_dynamic_backtrack.rs @@ -14,8 +14,9 @@ extern crate regex; macro_rules! regex { ($re:expr) => {{ - let e = Some(::regex::internal::MatchEngine::Backtrack); - ::regex::Regex::with_engine(e, 10 * (1 << 20), $re).unwrap() + use regex::internal::ExecBuilder; + ExecBuilder::new($re).bounded_backtracking() + .build().unwrap().into_regex() }} } diff --git a/tests/test_dynamic_backtrack_bytes.rs b/tests/test_dynamic_backtrack_bytes.rs new file mode 100644 index 0000000000..effbe55012 --- /dev/null +++ b/tests/test_dynamic_backtrack_bytes.rs @@ -0,0 +1,28 @@ +// Copyright 2014-2015 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +#![cfg_attr(feature = "pattern", feature(pattern))] + +extern crate regex; + +macro_rules! regex { + ($re:expr) => {{ + use regex::internal::ExecBuilder; + ExecBuilder::new($re).bounded_backtracking().bytes(true) + .build().unwrap().into_regex() + }} +} + +#[cfg(feature = "pattern")] +macro_rules! searcher_expr { ($e:expr) => ($e) } +#[cfg(not(feature = "pattern"))] +macro_rules! searcher_expr { ($e:expr) => ({}) } + +mod tests; diff --git a/regex_macros/tests/test_dynamic_nfa.rs b/tests/test_dynamic_nfa.rs similarity index 85% rename from regex_macros/tests/test_dynamic_nfa.rs rename to tests/test_dynamic_nfa.rs index 5498daf6fc..959daa9eb3 100644 --- a/regex_macros/tests/test_dynamic_nfa.rs +++ b/tests/test_dynamic_nfa.rs @@ -14,8 +14,8 @@ extern crate regex; macro_rules! regex { ($re:expr) => {{ - let e = Some(::regex::internal::MatchEngine::Nfa); - ::regex::Regex::with_engine(e, 10 * (1 << 20), $re).unwrap() + use regex::internal::ExecBuilder; + ExecBuilder::new($re).nfa().build().unwrap().into_regex() }} } diff --git a/tests/test_dynamic_nfa_bytes.rs b/tests/test_dynamic_nfa_bytes.rs new file mode 100644 index 0000000000..3e81c1d20a --- /dev/null +++ b/tests/test_dynamic_nfa_bytes.rs @@ -0,0 +1,27 @@ +// Copyright 2014-2015 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +#![cfg_attr(feature = "pattern", feature(pattern))] + +extern crate regex; + +macro_rules! regex { + ($re:expr) => {{ + use regex::internal::ExecBuilder; + ExecBuilder::new($re).nfa().bytes(true).build().unwrap().into_regex() + }} +} + +#[cfg(feature = "pattern")] +macro_rules! searcher_expr { ($e:expr) => ($e) } +#[cfg(not(feature = "pattern"))] +macro_rules! searcher_expr { ($e:expr) => ({}) } + +mod tests; diff --git a/regex_macros/tests/test_native.rs b/tests/test_native.rs similarity index 100% rename from regex_macros/tests/test_native.rs rename to tests/test_native.rs diff --git a/regex_macros/tests/tests.rs b/tests/tests.rs similarity index 79% rename from regex_macros/tests/tests.rs rename to tests/tests.rs index d2a60306d6..ad90d71e93 100644 --- a/regex_macros/tests/tests.rs +++ b/tests/tests.rs @@ -276,6 +276,37 @@ noparse!(fail_range_end_no_begin, r"[a-\A]"); noparse!(fail_range_end_no_end, r"[a-\z]"); noparse!(fail_range_end_no_boundary, r"[a-\b]"); +macro_rules! matiter( + ($name:ident, $re:expr, $text:expr) => ( + #[test] + fn $name() { + let text = $text; + let expected: Vec<(usize, usize)> = vec![]; + let r = regex!($re); + let got: Vec<_> = r.find_iter(text).collect(); + if expected != got { + panic!("For RE '{}' against '{:?}', \ + expected '{:?}' but got '{:?}'", + $re, text, expected, got); + } + } + ); + ($name:ident, $re:expr, $text:expr, $($loc:tt)+) => ( + #[test] + fn $name() { + let text = $text; + let expected: Vec<_> = vec!($($loc)+); + let r = regex!($re); + let got: Vec<_> = r.find_iter(text).collect(); + if expected != got { + panic!("For RE '{}' against '{:?}', \ + expected '{:?}' but got '{:?}'", + $re, text, expected, got); + } + } + ); +); + macro_rules! mat( ($name:ident, $re:expr, $text:expr, $($loc:tt)+) => ( #[test] @@ -342,11 +373,69 @@ mat!(match_flag_ungreedy, "(?U)a+", "aa", Some((0, 1))); mat!(match_flag_ungreedy_greedy, "(?U)a+?", "aa", Some((0, 2))); mat!(match_flag_ungreedy_noop, "(?U)(?-U)a+", "aa", Some((0, 2))); +// More exercising of multi-line flag. +matiter!(match_multi_1, r"(?m)^[a-z]+$", "abc\ndef\nxyz", + (0, 3), (4, 7), (8, 11)); +matiter!(match_multi_2, r"(?m)^$", "abc\ndef\nxyz"); +matiter!(match_multi_3, r"(?m)^", "abc\ndef\nxyz", + (0, 0), (4, 4), (8, 8)); +matiter!(match_multi_4, r"(?m)$", "abc\ndef\nxyz", + (3, 3), (7, 7), (11, 11)); +matiter!(match_multi_5, r"(?m)^[a-z]", "abc\ndef\nxyz", + (0, 1), (4, 5), (8, 9)); +matiter!(match_multi_6, r"(?m)[a-z]^", "abc\ndef\nxyz"); +matiter!(match_multi_7, r"(?m)[a-z]$", "abc\ndef\nxyz", + (2, 3), (6, 7), (10, 11)); +matiter!(match_multi_8, r"(?m)$[a-z]", "abc\ndef\nxyz"); +matiter!(match_multi_9, r"(?m)^$", "", (0, 0)); + +matiter!(match_multi_rep_1, r"(?m)(?:^$)*", "a\nb\nc", + (0, 0), (1, 1), (2, 2), (3, 3), (4, 4), (5, 5)); +matiter!(match_multi_rep_2, r"(?m)(?:^|a)+", "a\naaa\n", + (0, 0), (2, 2), (3, 5), (6, 6)); +matiter!(match_multi_rep_3, r"(?m)(?:^|a)*", "a\naaa\n", + (0, 1), (2, 5), (6, 6)); +matiter!(match_multi_rep_4, r"(?m)(?:^[a-z])+", "abc\ndef\nxyz", + (0, 1), (4, 5), (8, 9)); +matiter!(match_multi_rep_5, r"(?m)(?:^[a-z]{3}\n?)+", "abc\ndef\nxyz", + (0, 11)); +matiter!(match_multi_rep_6, r"(?m)(?:^[a-z]{3}\n?)*", "abc\ndef\nxyz", + (0, 11)); +matiter!(match_multi_rep_7, r"(?m)(?:\n?[a-z]{3}$)+", "abc\ndef\nxyz", + (0, 11)); +matiter!(match_multi_rep_8, r"(?m)(?:\n?[a-z]{3}$)*", "abc\ndef\nxyz", + (0, 11)); +matiter!(match_multi_rep_9, r"(?m)^*", "\naa\n", + (0, 0), (1, 1), (2, 2), (3, 3), (4, 4)); +matiter!(match_multi_rep_10, r"(?m)^+", "\naa\n", + (0, 0), (1, 1), (4, 4)); +matiter!(match_multi_rep_11, r"(?m)$*", "\naa\n", + (0, 0), (1, 1), (2, 2), (3, 3), (4, 4)); +matiter!(match_multi_rep_12, r"(?m)$+", "\naa\n", + (0, 0), (3, 3), (4, 4)); +matiter!(match_multi_rep_13, r"(?m)(?:$\n)+", "\n\naaa\n\n", + (0, 2), (5, 7)); +matiter!(match_multi_rep_14, r"(?m)(?:$\n)*", "\n\naaa\n\n", + (0, 2), (3, 3), (4, 4), (5, 7)); +matiter!(match_multi_rep_15, r"(?m)(?:$\n^)+", "\n\naaa\n\n", + (0, 2), (5, 7)); +matiter!(match_multi_rep_16, r"(?m)(?:^|$)+", "\n\naaa\n\n", + (0, 0), (1, 1), (2, 2), (5, 5), (6, 6), (7, 7)); +// matiter!(match_multi_rep_14, r"(?m)(?:$\n)*", "\n\naaa\n\n", + // (0, 2), (3, 3), (4, 4), (5, 7)); + +matiter!(match_start_end_empty, r"^$", "", (0, 0)); +matiter!(match_start_end_empty_many_1, r"^$^$^$", "", (0, 0)); +matiter!(match_start_end_empty_many_2, r"^^^$$$", "", (0, 0)); +matiter!(match_start_end_empty_rev, r"$^", "", (0, 0)); +matiter!(match_start_end_empty_rep, r"(?:^$)*", "a\nb\nc", + (0, 0), (1, 1), (2, 2), (3, 3), (4, 4), (5, 5)); +matiter!(match_start_end_empty_rep_rev, r"(?:$^)*", "a\nb\nc", + (0, 0), (1, 1), (2, 2), (3, 3), (4, 4), (5, 5)); + // Some Unicode tests. // A couple of these are commented out because something in the guts of macro // expansion is creating invalid byte strings. -// mat!(uni_literal, r"Ⅰ", "Ⅰ", Some((0, 3))) -// mat!(uni_case_not, r"Δ", "δ", None) mat!(uni_one, r"\pN", "Ⅰ", Some((0, 3))); mat!(uni_mixed, r"\pN+", "Ⅰ1Ⅱ2", Some((0, 8))); mat!(uni_not, r"\PN+", "abⅠ", Some((0, 2))); @@ -409,6 +498,8 @@ fn regression_captures_rep() { mat!(regression_alt_in_alt1, r"ab?|$", "az", Some((0, 1))); mat!(regression_alt_in_alt2, r"^(.*?)(\n|\r\n?|$)", "ab\rcd", Some((0, 3))); +mat!(one_unicode, r"☃", "☃", Some((0, 3))); + // A whole mess of tests from Glenn Fowler's regex test suite. // Generated by the 'src/etc/regex-match-tests' program. #[path = "matches.rs"]