Update re2

third_party/re2/util/stringprintf.cc

 // Copyright 2002 The RE2 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 "util/util.h"
 
-namespace re2 { 
+namespace re2 {
 
 static void StringAppendV(string* dst, const char* format, va_list ap) {
   // First try with a small fixed size buffer
   char space[1024];
 
   // It's possible for methods that use a va_list to invalidate
   // the data in it upon use.  The fix is to make a copy
   // of the structure before using it and use that copy instead.
   va_list backup_ap;
   va_copy(backup_ap, ap);
   int result = vsnprintf(space, sizeof(space), format, backup_ap);
   va_end(backup_ap);
 
-  if ((result >= 0) && (result < sizeof(space))) {
+  if ((result >= 0) && (static_cast<unsigned long>(result) < sizeof(space))) {
     // It fit
     dst->append(space, result);
     return;
   }
 
   // Repeatedly increase buffer size until it fits
   int length = sizeof(space);
   while (true) {
     if (result < 0) {
       // Older behavior: just try doubling the buffer size
       length *= 2;
     } else {
       // We need exactly "result+1" characters
       length = result+1;
     }
     char* buf = new char[length];
 
     // Restore the va_list before we use it again
     va_copy(backup_ap, ap);
+#if !defined(_WIN32)
     result = vsnprintf(buf, length, format, backup_ap);
+#else
+    // On Windows, the function takes five arguments, not four. With an array,
+    // the buffer size will be inferred, but not with a pointer. C'est la vie.
+    // (See https://github.com/google/re2/issues/40 for more details.)
+    result = vsnprintf(buf, length, _TRUNCATE, format, backup_ap);
+#endif
     va_end(backup_ap);
 
     if ((result >= 0) && (result < length)) {
       // It fit
       dst->append(buf, result);
       delete[] buf;
       return;
     }
     delete[] buf;
   }
@@ skipping 17 matching lines @@
 }
 
 void StringAppendF(string* dst, const char* format, ...) {
   va_list ap;
   va_start(ap, format);
   StringAppendV(dst, format, ap);
   va_end(ap);
 }
 
 }  // namespace re2