Update DateRewriter to be able to handle 3-digits.

This CL updates DateRewriter to rewrite 3-digits segments to date and
time.

3-digits are splitted in two ways (DDD to D+DD and DD+D).  The
candidates are organized in the following order:
  1. description (date/time)
  2. split type (D+DD/DD+D)
  3. string format (XX:XX, etc)

BUG=
TEST=unittest
REF_BUG=20059084
REF_CL=90971460

src/mozc_version_template.txt

@@ -1,6 +1,6 @@
 MAJOR=2
 MINOR=17
-BUILD=2238
+BUILD=2239
 REVISION=102
 # NACL_DICTIONARY_VERSION is the target version of the system dictionary to be
 # downloaded by NaCl Mozc.

src/rewriter/date_rewriter.cc

@@ -2322,10 +2322,10 @@ bool IsNDigits(const string &value, int n) {
 //      - All the meta candidates are based on "cd" (e.g. "CD", "Cd").
 //      Therefore to get "2223" we should access the raw input.
 // Prerequisit: |segments| has only one conversion segment.
-const bool GetNDigits(const composer::Composer &composer,
-                      const Segments &segments,
-                      int n,
-                      string *output) {
+bool GetNDigits(const composer::Composer &composer,
+                const Segments &segments,
+                int n,
+                string *output) {
   DCHECK(output);
   DCHECK_EQ(1, segments.conversion_segments_size());
   const Segment &segment = segments.conversion_segment(0);
@@ -2360,8 +2360,8 @@ const bool GetNDigits(const composer::Composer &composer,
 }
 }  // namespace
 
-bool DateRewriter::RewriteFourDigits(const composer::Composer &composer,
-                                     Segments *segments) const {
+bool DateRewriter::RewriteConsecutiveDigits(const composer::Composer &composer,
+                                            Segments *segments) const {
   if (segments->conversion_segments_size() != 1) {
     // This method rewrites a segment only when the segments has only
     // one conversion segment.
@@ -2371,8 +2371,10 @@ bool DateRewriter::RewriteFourDigits(const composer::Composer &composer,
   }
 
   string key;
-  if (!GetNDigits(composer, *segments, 4, &key)) {
-    // No four digit key is available.
+  // Currently three and four consecutive digits are converted
+  if (!GetNDigits(composer, *segments, 3, &key) &&
+      !GetNDigits(composer, *segments, 4, &key)) {
+    // No three or four digit key is available.
     return false;
   }
 
@@ -2470,7 +2472,7 @@ bool DateRewriter::Rewrite(const ConversionRequest &request,
   }
 
   if (request.has_composer()) {
-    modified |= RewriteFourDigits(request.composer(), segments);
+    modified |= RewriteConsecutiveDigits(request.composer(), segments);
   }
 
   return modified;

src/rewriter/date_rewriter.h

@@ -79,16 +79,17 @@ class DateRewriter : public RewriterInterface  {
   bool RewriteAd(Segment *segment) const;
   bool RewriteWeekday(Segment *segment) const;
 
-  // When only one conversion segment has four number characters,
+  // When only one conversion segment has consecutive number characters,
   // this function adds date and time candidates.
   // e.g.)
   //   key  -> candidates will be added
   //   ------------------------------------------------
   //   0101 -> "1月1日、01/01、1時1分,午前1時1分、1:01"
   //   2020 -> "20時20分、午後8時20分、20:20"
   //   2930 -> "29時30分、29時半、午前5時30分、午前5時半"
-  bool RewriteFourDigits(const composer::Composer &composer,
-                         Segments *segments) const;
+  //   123  -> "1月23日、01/23、1:23"
+  bool RewriteConsecutiveDigits(const composer::Composer &composer,
+                                Segments *segments) const;
 
   bool AdToEra(int year, vector<string> *results) const;
 

src/rewriter/date_rewriter_test.cc

@@ -1130,6 +1130,53 @@ TEST_F(DateRewriterTest, NumberRewriterTest) {
   // "日付"
   EXPECT_EQ(0, CountDescription(segments, "\xE6\x97\xA5\xE4\xBB\x98"));
 
+  // 123 is expected 3 time candidates and 2 date candidates
+  InitSegment("123", "123", &segments);
+  EXPECT_TRUE(rewriter.Rewrite(conversion_request, &segments));
+  // "時刻"
+  EXPECT_EQ(3, CountDescription(segments, "\xE6\x99\x82\xE5\x88\xBB"));
+  EXPECT_TRUE(ContainCandidate(segments, "1:23"));
+  // "1時23分"
+  EXPECT_TRUE(ContainCandidate(segments,
+                               "\x31\xe6\x99\x82\x32\x33\xe5\x88\x86"));
+  // "午前1時23分"
+  EXPECT_TRUE(ContainCandidate(
+      segments,
+      "\xe5\x8d\x88\xe5\x89\x8d\x31\xe6\x99\x82\x32\x33\xe5\x88\x86"));
+
+  // "日付"
+  EXPECT_EQ(2, CountDescription(segments, "\xE6\x97\xA5\xE4\xBB\x98"));
+  EXPECT_TRUE(ContainCandidate(segments, "01/23"));
+  // "1月23日"
+  EXPECT_TRUE(ContainCandidate(segments,
+                               "\x31\xe6\x9c\x88\x32\x33\xe6\x97\xa5"));
+
+  // 346 is expected 3 time candidates and 0 date candidate
+  InitSegment("346", "346", &segments);
+  EXPECT_TRUE(rewriter.Rewrite(conversion_request, &segments));
+  // "時刻"
+  EXPECT_EQ(3, CountDescription(segments, "\xE6\x99\x82\xE5\x88\xBB"));
+  EXPECT_TRUE(ContainCandidate(segments, "3:46"));
+  // "3時46分"
+  EXPECT_TRUE(ContainCandidate(segments,
+                               "\x33\xe6\x99\x82\x34\x36\xe5\x88\x86"));
+  // "午前3時46分"
+  EXPECT_TRUE(ContainCandidate(
+        segments,
+        "\xe5\x8d\x88\xe5\x89\x8d\x33\xe6\x99\x82\x34\x36\xe5\x88\x86"));
+
+  // "日付"
+  EXPECT_EQ(0, CountDescription(segments, "\xE6\x97\xA5\xE4\xBB\x98"));
+
+  // 765 is expected 0 time candidate and 0 date candidate
+  InitSegment("765", "765", &segments);
+  EXPECT_FALSE(rewriter.Rewrite(conversion_request, &segments));
+  // "時刻"
+  EXPECT_EQ(0, CountDescription(segments, "\xE6\x99\x82\xE5\x88\xBB"));
+
+  // "日付"
+  EXPECT_EQ(0, CountDescription(segments, "\xE6\x97\xA5\xE4\xBB\x98"));
+
   // Especially for mobile, look at meta candidates' value, too.
   // "あかあか" on 12keys layout will be transliterated to "1212".
   InitMetaSegment(