fix interaction of space flag and '+' flag, as well as '-' flag and '…

…0' flag (#1687)
fmtlib · May 17, 2020 · 6b219a5 · 6b219a5
1 parent eee2023
commit 6b219a5
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Showing 2 changed files with 29 additions and 3 deletions.
diff --git a/include/fmt/printf.h b/include/fmt/printf.h
@@ -405,7 +405,9 @@ void basic_printf_context<OutputIt, Char>::parse_flags(format_specs& specs,
       specs.fill[0] = '0';
       break;
     case ' ':
-      specs.sign = sign::space;
+      if (specs.sign != sign::plus) {
+        specs.sign = sign::space;
+      }
       break;
     case '#':
       specs.alt = true;
@@ -517,10 +519,11 @@ OutputIt basic_printf_context<OutputIt, Char>::format() {
     if (specs.alt && visit_format_arg(detail::is_zero_int(), arg))
       specs.alt = false;
     if (specs.fill[0] == '0') {
-      if (arg.is_arithmetic())
+      if (arg.is_arithmetic() && specs.align != align::left)
         specs.align = align::numeric;
       else
-        specs.fill[0] = ' ';  // Ignore '0' flag for non-numeric types.
+        specs.fill[0] = ' ';  // Ignore '0' flag for non-numeric types or if '-'
+                              // flag is also present.
     }
 
     // Parse length and convert the argument to the required type.

diff --git a/test/printf-test.cc b/test/printf-test.cc
@@ -151,6 +151,18 @@ TEST(PrintfTest, PlusFlag) {
 
   // '+' flag is ignored for non-numeric types.
   EXPECT_PRINTF("x", "%+c", 'x');
+
+  // '+' flag wins over space flag
+  EXPECT_PRINTF("+42", "%+ d", 42);
+  EXPECT_PRINTF("-42", "%+ d", -42);
+  EXPECT_PRINTF("+42", "% +d", 42);
+  EXPECT_PRINTF("-42", "% +d", -42);
+  EXPECT_PRINTF("+0042", "% +05d", 42);
+  EXPECT_PRINTF("+0042", "%0+ 5d", 42);
+
+  // '+' flag and space flag are both ignored for non-numeric types.
+  EXPECT_PRINTF("x", "%+ c", 'x');
+  EXPECT_PRINTF("x", "% +c", 'x');
 }
 
 TEST(PrintfTest, MinusFlag) {
@@ -160,6 +172,17 @@ TEST(PrintfTest, MinusFlag) {
   EXPECT_PRINTF("7    ", "%-5d", 7);
   EXPECT_PRINTF("97   ", "%-5hhi", 'a');
   EXPECT_PRINTF("a    ", "%-5c", 'a');
+
+  // '0' flag is ignored if '-' flag is given
+  EXPECT_PRINTF("7    ", "%-05d", 7);
+  EXPECT_PRINTF("7    ", "%0-5d", 7);
+  EXPECT_PRINTF("a    ", "%-05c", 'a');
+  EXPECT_PRINTF("a    ", "%0-5c", 'a');
+  EXPECT_PRINTF("97   ", "%-05hhi", 'a');
+  EXPECT_PRINTF("97   ", "%0-5hhi", 'a');
+
+  // '-' and space flag don't interfere
+  EXPECT_PRINTF(" 42", "%- d", 42);
 }
 
 TEST(PrintfTest, SpaceFlag) {