base: Add HexDigitToInt function to string_util.h

Removed duplicated HexToInt functions and converted the callers along the way.

BUG=None
TEST=trybots and out/Debug/base_unittests --gtest_filter=StringUtilTest.HexDigitToInt

Signed-off-by: Thiago Farina <tfarina@chromium.org>

Review URL: http://codereview.chromium.org/2836069

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@54473 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 4 insertions, 21 deletions

diff --git a/net/base/escape.cc b/net/base/escape.cc
index d9bfcee..3c39f95 100644
--- a/net/base/escape.cc
+++ b/net/base/escape.cc
@@ -15,18 +15,6 @@
 
 namespace {
 
-template <class char_type>
-inline char_type HexToInt(char_type ch) {
-  if (ch >= '0' && ch <= '9')
-    return ch - '0';
-  if (ch >= 'A' && ch <= 'F')
-    return ch - 'A' + 10;
-  if (ch >= 'a' && ch <= 'f')
-    return ch - 'a' + 10;
-  NOTREACHED();
-  return 0;
-}
-
 static const char* const kHexString = "0123456789ABCDEF";
 inline char IntToHex(int i) {
   DCHECK(i >= 0 && i <= 15) << i << " not a hex value";
@@ -136,8 +124,8 @@ STR UnescapeURLImpl(const STR& escaped_text,
       const typename STR::value_type least_sig_digit(
           static_cast<typename STR::value_type>(escaped_text[i + 2]));
       if (IsHexDigit(most_sig_digit) && IsHexDigit(least_sig_digit)) {
-        unsigned char value = HexToInt(most_sig_digit) * 16 +
-            HexToInt(least_sig_digit);
+        unsigned char value = HexDigitToInt(most_sig_digit) * 16 +
+            HexDigitToInt(least_sig_digit);
         if (value >= 0x80 ||  // Unescape all high-bit characters.
             // For 7-bit characters, the lookup table tells us all valid chars.
             (kUrlUnescape[value] ||
diff --git a/net/base/net_util.cc b/net/base/net_util.cc
index e25eb50..1d903b8 100644
--- a/net/base/net_util.cc
+++ b/net/base/net_util.cc
@@ -186,12 +186,6 @@ STR GetSpecificHeaderT(const STR& headers, const STR& name) {
   return ret;
 }
 
-inline unsigned char HexToInt(unsigned char c) {
-  DCHECK(IsHexDigit(c));
-  static unsigned char kOffset[4] = {0, 0x30u, 0x37u, 0x57u};
-  return c - kOffset[(c >> 5) & 3];
-}
-
 // Similar to Base64Decode. Decodes a Q-encoded string to a sequence
 // of bytes. If input is invalid, return false.
 bool QPDecode(const std::string& input, std::string* output) {
@@ -207,7 +201,8 @@ bool QPDecode(const std::string& input, std::string* output) {
       }
       if (IsHexDigit(static_cast<unsigned char>(*(it + 1))) &&
           IsHexDigit(static_cast<unsigned char>(*(it + 2)))) {
-        unsigned char ch = HexToInt(*(it + 1)) * 16 + HexToInt(*(it + 2));
+        unsigned char ch = HexDigitToInt(*(it + 1)) * 16 +
+                           HexDigitToInt(*(it + 2));
         temp.push_back(static_cast<char>(ch));
         ++it;
         ++it;