third_party/protobuf: Update to HEAD (83d681ee2c)

third_party/protobuf/src/google/protobuf/stubs/substitute.cc

 // Protocol Buffers - Google's data interchange format
 // Copyright 2008 Google Inc.  All rights reserved.
 // https://developers.google.com/protocol-buffers/
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
@@ skipping 95 matching lines @@
 
   if (size == 0) return;
 
   // Build the string.
   int original_size = output->size();
   STLStringResizeUninitialized(output, original_size + size);
   char* target = string_as_array(output) + original_size;
   for (int i = 0; format[i] != '\0'; i++) {
     if (format[i] == '$') {
       if (ascii_isdigit(format[i+1])) {
-        const SubstituteArg* src = args_array[format[i+1] - '0'];
+        unsigned int index = format[i+1] - '0';
+        assert(index < 10);
+        const SubstituteArg* src = args_array[index];
         memcpy(target, src->data(), src->size());
         target += src->size();
         ++i;  // Skip next char.
       } else if (format[i+1] == '$') {
         *target++ = '$';
         ++i;  // Skip next char.
       }
     } else {
       *target++ = format[i];
     }
   }
 
   GOOGLE_DCHECK_EQ(target - output->data(), output->size());
 }
 
 }  // namespace strings
 }  // namespace protobuf
 }  // namespace google