Revert "Revert "Cleanup some numeric code.""

core/src/fxcrt/fx_basic_wstring.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 <stddef.h>  // For offsetof().
+#include <cctype>
 
 #include "../../include/fxcrt/fx_basic.h"
 #include "../../../third_party/base/numerics/safe_math.h"
 
 // static
 CFX_WideString::StringData* CFX_WideString::StringData::Create(int nLen) {
   // TODO(palmer): |nLen| should really be declared as |size_t|, or
   // at least unsigned.
   if (nLen == 0 || nLen < 0) {
     return NULL;
@@ skipping 740 matching lines @@
       } else if (*lpsz == '*') {
         nWidth = va_arg(argList, int);
       } else if (*lpsz == '-' || *lpsz == '+' || *lpsz == '0' || *lpsz == ' ')
         ;
       else {
         break;
       }
     }
     if (nWidth == 0) {
       nWidth = FXSYS_wtoi(lpsz);
-      for (; *lpsz != 0 && (*lpsz) <= '9' && (*lpsz) >= '0'; lpsz++)
+      for (; *lpsz != 0 && std::isdigit(*lpsz); lpsz++)
         ;
     }
     if (nWidth < 0 || nWidth > 128 * 1024) {
       lpszFormat = L"Bad width";
       nMaxLen = 10;
       break;
     }
     int nPrecision = 0;
     if (*lpsz == '.') {
       lpsz++;
       if (*lpsz == '*') {
         nPrecision = va_arg(argList, int);
         lpsz++;
       } else {
         nPrecision = FXSYS_wtoi(lpsz);
-        for (; *lpsz != 0 && (*lpsz) >= '0' && (*lpsz) <= '9'; lpsz++)
+        for (; *lpsz != 0 && std::isdigit(*lpsz); lpsz++)
           ;
       }
     }
     if (nPrecision < 0 || nPrecision > 128 * 1024) {
       lpszFormat = L"Bad precision";
       nMaxLen = 14;
       break;
     }
     int nModifier = 0;
     if (*lpsz == L'I' && *(lpsz + 1) == L'6' && *(lpsz + 2) == L'4') {
@@ skipping 262 matching lines @@
       return (CFX_CharMap*)&g_DefaultJISMapper;
     case 936:
       return (CFX_CharMap*)&g_DefaultGBKMapper;
     case 949:
       return (CFX_CharMap*)&g_DefaultUHCMapper;
     case 950:
       return (CFX_CharMap*)&g_DefaultBig5Mapper;
   }
   return NULL;
 }