Fix FXSYS_StrToInt()

core/fxcrt/fx_basic_gcc.cpp

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include <cctype>
 #include <cwctype>
 #include <limits>
 
 #include "core/include/fxcrt/fx_ext.h"
 #include "core/include/fxcrt/fx_string.h"
 
 template <typename IntType, typename CharType>
 IntType FXSYS_StrToInt(const CharType* str) {
   if (!str)
     return 0;
 
-  bool neg = std::numeric_limits<IntType>::is_signed && *str == '-';
-  if (neg)
+  // Process the sign.
+  bool neg = *str == '-';
+  if (neg || *str == '+')
     str++;
 
   IntType num = 0;
   while (*str && FXSYS_isDecimalDigit(*str)) {
     IntType val = FXSYS_toDecimalDigit(*str);
-    if (num > (std::numeric_limits<IntType>::max() - val) / 10)
-      break;
+    if (num > (std::numeric_limits<IntType>::max() - val) / 10) {
+      if (neg && std::numeric_limits<IntType>::is_signed) {
+        // Return MIN when the represented number is signed type and is smaller
+        // than the min value.
+        return std::numeric_limits<IntType>::min();
+      } else {
+        // Return MAX when the represented number is signed type and is larger
+        // than the max value, or the number is unsigned type and out of range.
+        return std::numeric_limits<IntType>::max();
+      }
+    }
 
     num = num * 10 + val;
     str++;
   }
   return neg ? -num : num;
 }
 
 template <typename T, typename UT, typename STR_T>
 STR_T FXSYS_IntToStr(T value, STR_T str, int radix) {
   if (radix < 2 || radix > 16) {
@@ skipping 195 matching lines @@
       buf[wlen] = bstr[i];
     }
     wlen++;
   }
   return wlen;
 }
 #ifdef __cplusplus
 }
 #endif
 #endif