Fix integer overflow in FastUInt32ToBufferLeft

third_party/protobuf/src/google/protobuf/stubs/strutil.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 948 matching lines @@
   {'6','5'}, {'6','6'}, {'6','7'}, {'6','8'}, {'6','9'},
   {'7','0'}, {'7','1'}, {'7','2'}, {'7','3'}, {'7','4'},
   {'7','5'}, {'7','6'}, {'7','7'}, {'7','8'}, {'7','9'},
   {'8','0'}, {'8','1'}, {'8','2'}, {'8','3'}, {'8','4'},
   {'8','5'}, {'8','6'}, {'8','7'}, {'8','8'}, {'8','9'},
   {'9','0'}, {'9','1'}, {'9','2'}, {'9','3'}, {'9','4'},
   {'9','5'}, {'9','6'}, {'9','7'}, {'9','8'}, {'9','9'}
 };
 
 char* FastUInt32ToBufferLeft(uint32 u, char* buffer) {
-  int digits;
+  uint32 digits;
   const char *ASCII_digits = NULL;
   // The idea of this implementation is to trim the number of divides to as few
   // as possible by using multiplication and subtraction rather than mod (%),
   // and by outputting two digits at a time rather than one.
   // The huge-number case is first, in the hopes that the compiler will output
   // that case in one branch-free block of code, and only output conditional
   // branches into it from below.
   if (u >= 1000000000) {  // >= 1,000,000,000
     digits = u / 100000000;  // 100,000,000
     ASCII_digits = two_ASCII_digits[digits];
@@ skipping 1300 matching lines @@
 // Return length of a single UTF-8 source character
 int UTF8FirstLetterNumBytes(const char* src, int len) {
   if (len == 0) {
     return 0;
   }
   return kUTF8LenTbl[*reinterpret_cast<const uint8*>(src)];
 }
 
 }  // namespace protobuf
 }  // namespace google