Revert "Revert "Cleanup some numeric code.""

core/src/fxcrt/fx_basic_util.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 "../../include/fxcrt/fx_basic.h"
 #if _FXM_PLATFORM_ != _FXM_PLATFORM_WINDOWS_
 #include <sys/types.h>
 #include <dirent.h>
 #else
 #include <direct.h>
 #endif
+
+#include <cctype>
+
 CFX_PrivateData::~CFX_PrivateData() {
   ClearAll();
 }
 void FX_PRIVATEDATA::FreeData() {
   if (m_pData == NULL) {
     return;
   }
   if (m_bSelfDestruct) {
     delete (CFX_DestructObject*)m_pData;
   } else if (m_pCallback) {
@@ skipping 70 matching lines @@
     const FX_CHAR* str = strc.GetCStr();
     int len = strc.GetLength();
     FX_BOOL bNegative = FALSE;
     if (str[0] == '+') {
       cc++;
     } else if (str[0] == '-') {
       bNegative = TRUE;
       cc++;
     }
     while (cc < len) {
-      if (str[cc] < '0' || str[cc] > '9') {
+      if (!std::isdigit(str[cc]))
         break;
-      }
+
       integer = integer * 10 + str[cc] - '0';
-      if (integer < 0) {
+      if (integer < 0)
         break;
-      }
+
       cc++;
     }
     if (bNegative) {
       integer = -integer;
     }
     *(int*)pData = integer;
   } else {
     bInteger = FALSE;
     *(FX_FLOAT*)pData = FX_atof(strc);
   }
@@ skipping 243 matching lines @@
       d * m.b + e * m.e + f * m.h, d * m.c + e * m.f + f * m.i,
       g * m.a + h * m.d + i * m.g, g * m.b + h * m.e + i * m.h,
       g * m.c + h * m.f + i * m.i);
 }
 
 CFX_Vector_3by1 CFX_Matrix_3by3::TransformVector(const CFX_Vector_3by1& v) {
   return CFX_Vector_3by1(a * v.a + b * v.b + c * v.c,
                          d * v.a + e * v.b + f * v.c,
                          g * v.a + h * v.b + i * v.c);
 }