Revert x4 "Cleanup some numeric code."

This reverts commit b27902b8995bb3e003daed6b0811ed746763c68d.

Cleanup some numeric code.

This changes the various comparisons of char >= '0' && char <= '9' and
char < '0' || char > '9' to use std::isdigit checks. It also cleans up
a handful of hex to digit conversions to call one common method.

TBR=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1432973003 .

7 files changed, 49 insertions, 86 deletions

diff --git a/core/src/fxcrt/fx_basic_bstring.cpp b/core/src/fxcrt/fx_basic_bstring.cpp
index 574e57a9a6..9d64fbe139 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 "core/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 c352ee3f81..f8b0c7ac78 100644
--- a/core/src/fxcrt/fx_basic_gcc.cpp
+++ b/core/src/fxcrt/fx_basic_gcc.cpp
@@ -5,49 +5,29 @@
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include <limits>
-#include <cctype>
-#include <cwctype>
 
 #include "core/include/fxcrt/fx_ext.h"
 #include "core/include/fxcrt/fx_string.h"
 
-template <class T>
-T FXSYS_StrToInt(const FX_CHAR* str) {
+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)
-      break;
-
-    num = num * 10 + FXSYS_toDecimalDigit(*str);
-    str++;
-  }
-  return neg ? -num : num;
-}
-
-template <class T>
-T FXSYS_StrToInt(const FX_WCHAR* str) {
-  FX_BOOL neg = FALSE;
-  if (!str)
-    return 0;
-
   if (*str == '-') {
     neg = TRUE;
     str++;
   }
   T num = 0;
-  while (*str && std::iswdigit(*str)) {
-    if (num > (std::numeric_limits<T>::max() - 9) / 10)
+  while (*str) {
+    if ((*str) < '0' || (*str) > '9') {
       break;
-
-    num = num * 10 + FXSYS_toDecimalDigitWide(*str);
+    }
+    if (num > (std::numeric_limits<T>::max() - 9) / 10) {
+      break;
+    }
+    num = num * 10 + (*str) - '0';
     str++;
   }
   return neg ? -num : num;
@@ -91,16 +71,16 @@ STR_T FXSYS_IntToStr(T value, STR_T string, int radix) {
 extern "C" {
 #endif
 int32_t FXSYS_atoi(const FX_CHAR* str) {
-  return FXSYS_StrToInt<int32_t>(str);
+  return FXSYS_StrToInt<int32_t, const FX_CHAR*>(str);
 }
 int32_t FXSYS_wtoi(const FX_WCHAR* str) {
-  return FXSYS_StrToInt<int32_t>(str);
+  return FXSYS_StrToInt<int32_t, const FX_WCHAR*>(str);
 }
 int64_t FXSYS_atoi64(const FX_CHAR* str) {
-  return FXSYS_StrToInt<int64_t>(str);
+  return FXSYS_StrToInt<int64_t, const FX_CHAR*>(str);
 }
 int64_t FXSYS_wtoi64(const FX_WCHAR* str) {
-  return FXSYS_StrToInt<int64_t>(str);
+  return FXSYS_StrToInt<int64_t, const FX_WCHAR*>(str);
 }
 const FX_CHAR* FXSYS_i64toa(int64_t value, FX_CHAR* str, int radix) {
   return FXSYS_IntToStr<int64_t, uint64_t, FX_CHAR*>(value, str, radix);
diff --git a/core/src/fxcrt/fx_basic_util.cpp b/core/src/fxcrt/fx_basic_util.cpp
index b4c7064da2..3e9d6169cd 100644
--- a/core/src/fxcrt/fx_basic_util.cpp
+++ b/core/src/fxcrt/fx_basic_util.cpp
@@ -5,9 +5,6 @@
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include "core/include/fxcrt/fx_basic.h"
-#include "core/include/fxcrt/fx_ext.h"
-
-#include <cctype>
 
 #if _FXM_PLATFORM_ != _FXM_PLATFORM_WINDOWS_
 #include <sys/types.h>
@@ -105,11 +102,14 @@ void FX_atonum(const CFX_ByteStringC& strc, FX_BOOL& bInteger, void* pData) {
       bNegative = TRUE;
       cc++;
     }
-    while (cc < len && std::isdigit(str[cc])) {
-      // TODO(dsinclair): This is not the right way to handle overflow.
-      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 +146,7 @@ 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 +157,7 @@ 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 220ffbd57d..131672da2b 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 "core/include/fxcrt/fx_basic.h"
-#include "core/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::iswdigit(*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::iswdigit(*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_toDecimalDigitWide(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_toDecimalDigitWide(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 37437ae9ed..7eb86d6364 100644
--- a/core/src/fxcrt/fx_extension.cpp
+++ b/core/src/fxcrt/fx_extension.cpp
@@ -51,7 +51,9 @@ 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 +190,12 @@ 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;
@@ -291,3 +298,6 @@ 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 eff8878df0..0000000000
--- a/core/src/fxcrt/fx_extension_unittest.cpp
+++ /dev/null
@@ -1,24 +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'));
-}
-
-TEST(fxcrt, FXSYS_toDecimalDigitWide) {
-  EXPECT_EQ(7, FXSYS_toDecimalDigitWide(L'7'));
-  EXPECT_EQ(0, FXSYS_toDecimalDigitWide(L'a'));
-}
diff --git a/core/src/fxcrt/fx_xml_parser.cpp b/core/src/fxcrt/fx_xml_parser.cpp
index 2d3ff6631e..429bc38289 100644
--- a/core/src/fxcrt/fx_xml_parser.cpp
+++ b/core/src/fxcrt/fx_xml_parser.cpp
@@ -6,7 +6,6 @@
 
 #include "xml_int.h"
 
-#include "core/include/fxcrt/fx_ext.h"
 #include "core/include/fxcrt/fx_xml.h"
 
 CXML_Parser::~CXML_Parser() {
@@ -229,8 +228,9 @@ 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++;
@@ -242,7 +242,7 @@ 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 {