Reland "Cleanup some numeric code.""chromium/2567

This reverts commit 0569ab0b11b723d9bca4ddd642b0cf8828c4bdd1.

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.

R=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1449873003 .

7 files changed, 86 insertions, 49 deletions

diff --git a/core/src/fxcrt/fx_basic_bstring.cpp b/core/src/fxcrt/fx_basic_bstring.cpp
index 9d64fbe139..574e57a9a6 100644
--- a/core/src/fxcrt/fx_basic_bstring.cpp
+++ b/core/src/fxcrt/fx_basic_bstring.cpp
@@ -5,6 +5,7 @@
 // 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"
@@ -493,8 +494,8 @@ void CFX_ByteString::FormatV(const FX_CHAR* lpszFormat, va_list argList) {
     }
     if (nWidth == 0) {
       nWidth = FXSYS_atoi(lpsz);
-      for (; (*lpsz) >= '0' && (*lpsz) <= '9'; lpsz++)
-        ;
+      while (std::isdigit(*lpsz))
+        lpsz++;
     }
     if (nWidth < 0 || nWidth > 128 * 1024) {
       lpszFormat = "Bad width";
@@ -509,8 +510,8 @@ void CFX_ByteString::FormatV(const FX_CHAR* lpszFormat, va_list argList) {
         lpsz++;
       } else {
         nPrecision = FXSYS_atoi(lpsz);
-        for (; (*lpsz) >= '0' && (*lpsz) <= '9'; lpsz++)
-          ;
+        while (std::isdigit(*lpsz))
+          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 f8b0c7ac78..c352ee3f81 100644
--- a/core/src/fxcrt/fx_basic_gcc.cpp
+++ b/core/src/fxcrt/fx_basic_gcc.cpp
@@ -5,29 +5,49 @@
 // 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, class STR_T>
-T FXSYS_StrToInt(STR_T str) {
+template <class T>
+T FXSYS_StrToInt(const FX_CHAR* str) {
   FX_BOOL neg = FALSE;
-  if (str == NULL) {
+  if (!str)
     return 0;
-  }
+
   if (*str == '-') {
     neg = TRUE;
     str++;
   }
   T num = 0;
-  while (*str) {
-    if ((*str) < '0' || (*str) > '9') {
+  while (*str && std::isdigit(*str)) {
+    if (num > (std::numeric_limits<T>::max() - 9) / 10)
       break;
-    }
-    if (num > (std::numeric_limits<T>::max() - 9) / 10) {
+
+    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)
       break;
-    }
-    num = num * 10 + (*str) - '0';
+
+    num = num * 10 + FXSYS_toDecimalDigitWide(*str);
     str++;
   }
   return neg ? -num : num;
@@ -71,16 +91,16 @@ 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, const FX_CHAR*>(str);
+  return FXSYS_StrToInt<int32_t>(str);
 }
 int32_t FXSYS_wtoi(const FX_WCHAR* str) {
-  return FXSYS_StrToInt<int32_t, const FX_WCHAR*>(str);
+  return FXSYS_StrToInt<int32_t>(str);
 }
 int64_t FXSYS_atoi64(const FX_CHAR* str) {
-  return FXSYS_StrToInt<int64_t, const FX_CHAR*>(str);
+  return FXSYS_StrToInt<int64_t>(str);
 }
 int64_t FXSYS_wtoi64(const FX_WCHAR* str) {
-  return FXSYS_StrToInt<int64_t, const FX_WCHAR*>(str);
+  return FXSYS_StrToInt<int64_t>(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 3e9d6169cd..b4c7064da2 100644
--- a/core/src/fxcrt/fx_basic_util.cpp
+++ b/core/src/fxcrt/fx_basic_util.cpp
@@ -5,6 +5,9 @@
 // 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>
@@ -102,14 +105,11 @@ void FX_atonum(const CFX_ByteStringC& strc, FX_BOOL& bInteger, void* pData) {
       bNegative = TRUE;
       cc++;
     }
-    while (cc < len) {
-      if (str[cc] < '0' || str[cc] > '9') {
+    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)
         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 + str[cc] - '0';
+    value = value * 10 + FXSYS_toDecimalDigit(str[cc]);
     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] * (str[cc] - '0');
+      value += fraction_scales[scale] * FXSYS_toDecimalDigit(str[cc]);
       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 131672da2b..220ffbd57d 100644
--- a/core/src/fxcrt/fx_basic_wstring.cpp
+++ b/core/src/fxcrt/fx_basic_wstring.cpp
@@ -5,8 +5,10 @@
 // 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
@@ -765,8 +767,8 @@ void CFX_WideString::FormatV(const FX_WCHAR* lpszFormat, va_list argList) {
     }
     if (nWidth == 0) {
       nWidth = FXSYS_wtoi(lpsz);
-      for (; *lpsz != 0 && (*lpsz) <= '9' && (*lpsz) >= '0'; lpsz++)
-        ;
+      while (std::iswdigit(*lpsz))
+        ++lpsz;
     }
     if (nWidth < 0 || nWidth > 128 * 1024) {
       lpszFormat = L"Bad width";
@@ -781,8 +783,8 @@ void CFX_WideString::FormatV(const FX_WCHAR* lpszFormat, va_list argList) {
         lpsz++;
       } else {
         nPrecision = FXSYS_wtoi(lpsz);
-        for (; *lpsz != 0 && (*lpsz) >= '0' && (*lpsz) <= '9'; lpsz++)
-          ;
+        while (std::iswdigit(*lpsz))
+          ++lpsz;
       }
     }
     if (nPrecision < 0 || nPrecision > 128 * 1024) {
@@ -968,7 +970,7 @@ FX_FLOAT FX_wtof(const FX_WCHAR* str, int len) {
     if (str[cc] == '.') {
       break;
     }
-    integer = integer * 10 + str[cc] - '0';
+    integer = integer * 10 + FXSYS_toDecimalDigitWide(str[cc]);
     cc++;
   }
   FX_FLOAT fraction = 0;
@@ -976,7 +978,7 @@ FX_FLOAT FX_wtof(const FX_WCHAR* str, int len) {
     cc++;
     FX_FLOAT scale = 0.1f;
     while (cc < len) {
-      fraction += scale * (str[cc] - '0');
+      fraction += scale * FXSYS_toDecimalDigitWide(str[cc]);
       scale *= 0.1f;
       cc++;
     }
diff --git a/core/src/fxcrt/fx_extension.cpp b/core/src/fxcrt/fx_extension.cpp
index 7eb86d6364..37437ae9ed 100644
--- a/core/src/fxcrt/fx_extension.cpp
+++ b/core/src/fxcrt/fx_extension.cpp
@@ -51,9 +51,7 @@ 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);
 }
@@ -190,12 +188,7 @@ 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;
@@ -298,6 +291,3 @@ 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
new file mode 100644
index 0000000000..b12dcbe07f
--- /dev/null
+++ b/core/src/fxcrt/fx_extension_unittest.cpp
@@ -0,0 +1,24 @@
+// 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 "core/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 429bc38289..2d3ff6631e 100644
--- a/core/src/fxcrt/fx_xml_parser.cpp
+++ b/core/src/fxcrt/fx_xml_parser.cpp
@@ -6,6 +6,7 @@
 
 #include "xml_int.h"
 
+#include "core/include/fxcrt/fx_ext.h"
 #include "core/include/fxcrt/fx_xml.h"
 
 CXML_Parser::~CXML_Parser() {
@@ -228,9 +229,8 @@ FX_DWORD CXML_Parser::GetCharRef() {
             iState = 10;
             break;
           }
-          if (g_FXCRT_XML_IsDigital(ch)) {
-            code = code * 10 + ch - '0';
-          }
+          if (g_FXCRT_XML_IsDigital(ch))
+            code = code * 10 + FXSYS_toDecimalDigit(ch);
           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) + ch - '0';
+              code = (code << 4) + FXSYS_toDecimalDigit(ch);
             } else if (nHex == FXCRTM_XML_CHARTYPE_HexLowerLetter) {
               code = (code << 4) + ch - 87;
             } else {