Fix tautological compare in rlz.

rlz/lib/string_utils.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.
 //
 // String manipulation functions used in the RLZ library.
 
 #include "rlz/lib/string_utils.h"
 
 #include "rlz/lib/assert.h"
 
 namespace rlz_lib {
 
-bool IsAscii(char letter) {
-  return (letter >= 0x0 && letter < 0x80);
+bool IsAscii(unsigned char letter) {
+  return letter < 0x80;
 }
 
 bool GetHexValue(char letter, int* value) {
   if (!value) {
     ASSERT_STRING("GetHexValue: Invalid output paramter");
     return false;
   }
   *value = 0;
 
   if (letter >= '0' && letter <= '9')
@@ skipping 58 matching lines @@
   int index = data_len;
   while (index--) {
     string->at(2 * index) = kHex[data[index] >> 4];  // high digit
     string->at(2 * index + 1) = kHex[data[index] & 0x0F];  // low digit
   }
 
   return true;
 }
 
 }  // namespace rlz_lib