Revert "Revert "Revert "Cleanup some numeric code."""

This reverts commit e0e922db5fb77df9a5a9cc802096f484ed21da1c.

Broke Windows build.

FAILED: ninja -t msvc -e environment.x86 -- "C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\bin\amd64_x86\cl.exe" /nologo /showIncludes /FC @obj\core\src\fxcrt\fxcrt.fx_basic_gcc.obj.rsp /c ..\..\core\src\fxcrt\fx_basic_gcc.cpp /Foobj\core\src\fxcrt\fxcrt.fx_basic_gcc.obj /Fdobj\fxcrt.cc.pdb
e:\b\build\slave\windows\build\pdfium\core\src\fxcrt\fx_basic_gcc.cpp(28) : error C2220: warning treated as error - no 'object' file generated
        e:\b\build\slave\windows\build\pdfium\core\src\fxcrt\fx_basic_gcc.cpp(75) : see reference to function template instantiation 'T FXSYS_StrToInt<int32_t,const FX_WCHAR*>(STR_T)' being compiled
        with
        [
            T=int32_t
,            STR_T=const FX_WCHAR *
        ]
e:\b\build\slave\windows\build\pdfium\core\src\fxcrt\fx_basic_gcc.cpp(28) : warning C4244: 'argument' : conversion from 'const FX_WCHAR' to 'char', possible loss of data
FAILED: ninja -t msvc -e environment.x86 -- "C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\bin\amd64_x86\cl.exe" /nologo /showIncludes /FC @obj\core\src\fpdftext\fpdftext.fpdf_text.obj.rsp /c ..\..\core\src\fpdftext\fpdf_text.cpp /Foobj\core\src\fpdftext\fpdftext.fpdf_text.obj /Fdobj\fpdftext.cc.pdb
e:\b\build\slave\windows\build\pdfium\core\src\fpdftext\fpdf_text.cpp(439) : error C2039: 'isdigit' : is not a member of 'std'
FAILED: ninja -t msvc -e environment.x86 -- "C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\bin\amd64_x86\cl.exe" /nologo /showIncludes /FC @obj\core\src\fxcrt\fxcrt.fx_basic_wstring.obj.rsp /c ..\..\core\src\fxcrt\fx_basic_wstring.cpp /Foobj\core\src\fxcrt\fxcrt.fx_basic_wstring.obj /Fdobj\fxcrt.cc.pdb
e:\b\build\slave\windows\build\pdfium\core\src\fxcrt\fx_basic_wstring.cpp(973) : error C2220: warning treated as error - no 'object' file generated
e:\b\build\slave\windows\build\pdfium\core\src\fxcrt\fx_basic_wstring.cpp(973) : warning C4244: 'argument' : conversion from 'const FX_WCHAR' to 'char', possible loss of data
e:\b\build\slave\windows\build\pdfium\core\src\fxcrt\fx_basic_wstring.cpp(981) : warning C4244: 'argument' : conversion from 'const FX_WCHAR' to 'char', possible loss of data
FAILED: ninja -t msvc -e environment.x86 -- "C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\bin\amd64_x86\cl.exe" /nologo /showIncludes /FC @obj\core\src\fpdftext\fpdftext.fpdf_text_int.obj.rsp /c ..\..\core\src\fpdftext\fpdf_text_int.cpp /Foobj\core\src\fpdftext\fpdftext.fpdf_text_int.obj /Fdobj\fpdftext.cc.pdb
e:\b\build\slave\windows\build\pdfium\core\src\fpdftext\fpdf_text_int.cpp(2436) : error C2039: 'isdigit' : is not a member of 'std'
e:\b\build\slave\windows\build\pdfium\core\src\fpdftext\fpdf_text_int.cpp(2440) : error C2039: 'isdigit' : is not a member of 'std'
ninja: build stopped: subcommand failed.

TBR=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1431683008 .

7 files changed, 44 insertions, 59 deletions

diff --git a/core/src/fxcrt/fx_basic_bstring.cpp b/core/src/fxcrt/fx_basic_bstring.cpp
index 1b9d7a0344..c706912d9d 100644
--- a/core/src/fxcrt/fx_basic_bstring.cpp
+++ b/core/src/fxcrt/fx_basic_bstring.cpp
@@ -5,7 +5,6 @@
 // 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"
@@ -494,8 +493,8 @@ void CFX_ByteString::FormatV(const FX_CHAR* lpszFormat, va_list argList) {
     }
     if (nWidth == 0) {
       nWidth = FXSYS_atoi(lpsz);
-      while (std::isdigit(*lpsz))
-        lpsz++;
+      for (; (*lpsz) >= '0' && (*lpsz) <= '9'; lpsz++)
+        ;
     }
     if (nWidth < 0 || nWidth > 128 * 1024) {
       lpszFormat = "Bad width";
@@ -510,8 +509,8 @@ void CFX_ByteString::FormatV(const FX_CHAR* lpszFormat, va_list argList) {
         lpsz++;
       } else {
         nPrecision = FXSYS_atoi(lpsz);
-        while (std::isdigit(*lpsz))
-          lpsz++;
+        for (; (*lpsz) >= '0' && (*lpsz) <= '9'; lpsz++)
+          ;
       }
     }
     if (nPrecision < 0 || nPrecision > 128 * 1024) {
diff --git a/core/src/fxcrt/fx_basic_gcc.cpp b/core/src/fxcrt/fx_basic_gcc.cpp
index 250079913c..6f17482156 100644
--- a/core/src/fxcrt/fx_basic_gcc.cpp
+++ b/core/src/fxcrt/fx_basic_gcc.cpp
@@ -5,7 +5,6 @@
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include <limits>
-#include <cctype>
 
 #include "../../include/fxcrt/fx_ext.h"
 #include "../../include/fxcrt/fx_string.h"
@@ -13,19 +12,22 @@
 template <class T, class STR_T>
 T FXSYS_StrToInt(STR_T str) {
   FX_BOOL neg = FALSE;
-  if (!str)
+  if (str == NULL) {
     return 0;
-
+  }
   if (*str == '-') {
     neg = TRUE;
     str++;
   }
   T num = 0;
-  while (*str && std::isdigit(*str)) {
-    if (num > (std::numeric_limits<T>::max() - 9) / 10)
+  while (*str) {
+    if ((*str) < '0' || (*str) > '9') {
       break;
-
-    num = num * 10 + FXSYS_toDecimalDigit(*str);
+    }
+    if (num > (std::numeric_limits<T>::max() - 9) / 10) {
+      break;
+    }
+    num = num * 10 + (*str) - '0';
     str++;
   }
   return neg ? -num : num;
diff --git a/core/src/fxcrt/fx_basic_util.cpp b/core/src/fxcrt/fx_basic_util.cpp
index 78bdeee693..46a0dec1e5 100644
--- a/core/src/fxcrt/fx_basic_util.cpp
+++ b/core/src/fxcrt/fx_basic_util.cpp
@@ -5,17 +5,12 @@
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include "../../include/fxcrt/fx_basic.h"
-#include "../../include/fxcrt/fx_ext.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();
 }
@@ -105,11 +100,14 @@ void FX_atonum(const CFX_ByteStringC& strc, FX_BOOL& bInteger, void* pData) {
       bNegative = TRUE;
       cc++;
     }
-    while (cc < len && std::isdigit(str[cc])) {
-      integer = integer * 10 + FXSYS_toDecimalDigit(str[cc]);
-      if (integer < 0)
+    while (cc < len) {
+      if (str[cc] < '0' || str[cc] > '9') {
         break;
-
+      }
+      integer = integer * 10 + str[cc] - '0';
+      if (integer < 0) {
+        break;
+      }
       cc++;
     }
     if (bNegative) {
@@ -146,7 +144,7 @@ FX_FLOAT FX_atof(const CFX_ByteStringC& strc) {
     if (str[cc] == '.') {
       break;
     }
-    value = value * 10 + FXSYS_toDecimalDigit(str[cc]);
+    value = value * 10 + str[cc] - '0';
     cc++;
   }
   static const FX_FLOAT fraction_scales[] = {
@@ -157,7 +155,7 @@ FX_FLOAT FX_atof(const CFX_ByteStringC& strc) {
   if (cc < len && str[cc] == '.') {
     cc++;
     while (cc < len) {
-      value += fraction_scales[scale] * FXSYS_toDecimalDigit(str[cc]);
+      value += fraction_scales[scale] * (str[cc] - '0');
       scale++;
       if (scale == sizeof fraction_scales / sizeof(FX_FLOAT)) {
         break;
diff --git a/core/src/fxcrt/fx_basic_wstring.cpp b/core/src/fxcrt/fx_basic_wstring.cpp
index cb94d81196..c097e1fc09 100644
--- a/core/src/fxcrt/fx_basic_wstring.cpp
+++ b/core/src/fxcrt/fx_basic_wstring.cpp
@@ -5,10 +5,8 @@
 // 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 "../../include/fxcrt/fx_ext.h"
 #include "../../../third_party/base/numerics/safe_math.h"
 
 // static
@@ -767,8 +765,8 @@ void CFX_WideString::FormatV(const FX_WCHAR* lpszFormat, va_list argList) {
     }
     if (nWidth == 0) {
       nWidth = FXSYS_wtoi(lpsz);
-      while (std::isdigit(*lpsz))
-        ++lpsz;
+      for (; *lpsz != 0 && (*lpsz) <= '9' && (*lpsz) >= '0'; lpsz++)
+        ;
     }
     if (nWidth < 0 || nWidth > 128 * 1024) {
       lpszFormat = L"Bad width";
@@ -783,8 +781,8 @@ void CFX_WideString::FormatV(const FX_WCHAR* lpszFormat, va_list argList) {
         lpsz++;
       } else {
         nPrecision = FXSYS_wtoi(lpsz);
-        while (std::isdigit(*lpsz))
-          ++lpsz;
+        for (; *lpsz != 0 && (*lpsz) >= '0' && (*lpsz) <= '9'; lpsz++)
+          ;
       }
     }
     if (nPrecision < 0 || nPrecision > 128 * 1024) {
@@ -970,7 +968,7 @@ FX_FLOAT FX_wtof(const FX_WCHAR* str, int len) {
     if (str[cc] == '.') {
       break;
     }
-    integer = integer * 10 + FXSYS_toDecimalDigit(str[cc]);
+    integer = integer * 10 + str[cc] - '0';
     cc++;
   }
   FX_FLOAT fraction = 0;
@@ -978,7 +976,7 @@ FX_FLOAT FX_wtof(const FX_WCHAR* str, int len) {
     cc++;
     FX_FLOAT scale = 0.1f;
     while (cc < len) {
-      fraction += scale * FXSYS_toDecimalDigit(str[cc]);
+      fraction += scale * (str[cc] - '0');
       scale *= 0.1f;
       cc++;
     }
diff --git a/core/src/fxcrt/fx_extension.cpp b/core/src/fxcrt/fx_extension.cpp
index 4951fbde9c..d64a06d08b 100644
--- a/core/src/fxcrt/fx_extension.cpp
+++ b/core/src/fxcrt/fx_extension.cpp
@@ -7,7 +7,6 @@
 #include "../../include/fxcrt/fx_basic.h"
 #include "../../include/fxcrt/fx_ext.h"
 #include "extension.h"
-
 #if _FXM_PLATFORM_ == _FXM_PLATFORM_WINDOWS_
 #include <wincrypt.h>
 #else
@@ -51,7 +50,9 @@ IFX_MemoryStream* FX_CreateMemoryStream(uint8_t* pBuffer,
 IFX_MemoryStream* FX_CreateMemoryStream(FX_BOOL bConsecutive) {
   return new CFX_MemoryStream(bConsecutive);
 }
-
+#ifdef __cplusplus
+extern "C" {
+#endif
 FX_FLOAT FXSYS_tan(FX_FLOAT a) {
   return (FX_FLOAT)tan(a);
 }
@@ -188,7 +189,12 @@ FX_DWORD FX_HashCode_String_GetW(const FX_WCHAR* pStr,
   }
   return dwHashCode;
 }
-
+#ifdef __cplusplus
+}
+#endif
+#ifdef __cplusplus
+extern "C" {
+#endif
 void* FX_Random_MT_Start(FX_DWORD dwSeed) {
   FX_LPMTRANDOMCONTEXT pContext = FX_Alloc(FX_MTRANDOMCONTEXT, 1);
   pContext->mt[0] = dwSeed;
@@ -291,4 +297,6 @@ void FX_Random_GenerateCrypto(FX_DWORD* pBuffer, int32_t iCount) {
   FX_Random_GenerateBase(pBuffer, iCount);
 #endif
 }
-
+#ifdef __cplusplus
+}
+#endif
diff --git a/core/src/fxcrt/fx_extension_unittest.cpp b/core/src/fxcrt/fx_extension_unittest.cpp
deleted file mode 100644
index 2cadbbfede..0000000000
--- a/core/src/fxcrt/fx_extension_unittest.cpp
+++ /dev/null
@@ -1,19 +0,0 @@
-// Copyright 2015 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.
-
-#include "testing/gtest/include/gtest/gtest.h"
-
-#include "../../include/fxcrt/fx_ext.h"
-
-TEST(fxcrt, FXSYS_toHexDigit) {
-  EXPECT_EQ(10, FXSYS_toHexDigit('a'));
-  EXPECT_EQ(10, FXSYS_toHexDigit('A'));
-  EXPECT_EQ(7, FXSYS_toHexDigit('7'));
-  EXPECT_EQ(0, FXSYS_toHexDigit('i'));
-}
-
-TEST(fxcrt, FXSYS_toDecimalDigit) {
-  EXPECT_EQ(7, FXSYS_toDecimalDigit('7'));
-  EXPECT_EQ(0, FXSYS_toDecimalDigit('a'));
-}
diff --git a/core/src/fxcrt/fx_xml_parser.cpp b/core/src/fxcrt/fx_xml_parser.cpp
index 845fd84cfd..dc59ded2b7 100644
--- a/core/src/fxcrt/fx_xml_parser.cpp
+++ b/core/src/fxcrt/fx_xml_parser.cpp
@@ -5,9 +5,7 @@
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include "../../include/fxcrt/fx_xml.h"
-#include "../../include/fxcrt/fx_ext.h"
 #include "xml_int.h"
-
 CXML_Parser::~CXML_Parser() {
   if (m_bOwnedStream) {
     m_pDataAcc->Release();
@@ -228,8 +226,9 @@ FX_DWORD CXML_Parser::GetCharRef() {
             iState = 10;
             break;
           }
-          if (g_FXCRT_XML_IsDigital(ch))
-            code = code * 10 + FXSYS_toDecimalDigit(ch);
+          if (g_FXCRT_XML_IsDigital(ch)) {
+            code = code * 10 + ch - '0';
+          }
           break;
         case 4:
           m_dwIndex++;
@@ -241,7 +240,7 @@ FX_DWORD CXML_Parser::GetCharRef() {
               g_FXCRT_XML_ByteTypes[ch] & FXCRTM_XML_CHARTYPE_HexChar;
           if (nHex) {
             if (nHex == FXCRTM_XML_CHARTYPE_HexDigital) {
-              code = (code << 4) + FXSYS_toDecimalDigit(ch);
+              code = (code << 4) + ch - '0';
             } else if (nHex == FXCRTM_XML_CHARTYPE_HexLowerLetter) {
               code = (code << 4) + ch - 87;
             } else {