Merge latest changes from http://www.netlib.org/fp/dtoa.c into dtoa.cc

base/strings/string_number_conversions_unittest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/strings/string_number_conversions.h"
 
 #include <errno.h>
 #include <limits.h>
 #include <stddef.h>
 #include <stdint.h>
@@ skipping 872 matching lines @@
       {"8.32116e+55", 0x4b8b2628393e02cdULL},
   };
 
   for (const auto& test : cases) {
     double output;
     EXPECT_TRUE(StringToDouble(test.input, &output));
     EXPECT_EQ(bit_cast<uint64_t>(output), test.expected);
   }
 }
 
+TEST(StringNumberConversionsTest, StringToDoubleBugs) {
+  static const struct {
+    std::string input;
+    double output;
+    bool success;
+  } cases[] = {
+      // crbug.com/588726 timeout
+      {"-0.0010000000000000000000000000000000000000001e-256",
+       -1.0000000000000001e-259, true},
+  };
+
+  for (size_t i = 0; i < arraysize(cases); ++i) {

[scottmg, 2016/09/23 18:12:40]

Since there's only one case, it would be clearer to just have this call the
functions and EXPECT directly without a loop. And perhaps rename the test to
something like StringToDoubleHangBug588726.

[kcwu, 2016/09/23 19:23:06]

Done.

+    double output;
+    errno = 1;
+    EXPECT_EQ(cases[i].success, StringToDouble(cases[i].input, &output));
+    if (cases[i].success)
+      EXPECT_EQ(1, errno) << i;  // confirm that errno is unchanged.
+    EXPECT_DOUBLE_EQ(cases[i].output, output);
+  }
+}
+
 }  // namespace base