Optimize whitespace skipping in the CSSParser.

third_party/WebKit/Source/core/css/parser/CSSTokenizerInputStream.cpp

 // Copyright 2014 The Chromium 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 "core/css/parser/CSSTokenizerInputStream.h"
 
+#include "core/html/parser/HTMLParserIdioms.h"
 #include "core/html/parser/InputStreamPreprocessor.h"
 #include "wtf/text/StringToNumber.h"
 
 namespace blink {
 
 CSSTokenizerInputStream::CSSTokenizerInputStream(String input)
     : m_offset(0)
     , m_stringLength(input.length())
     , m_string(input.impl())
 {
 }
 
 UChar CSSTokenizerInputStream::peek(unsigned lookaheadOffset)
 {
     if ((m_offset + lookaheadOffset) >= m_stringLength)
         return kEndOfFileMarker;
     UChar result = (*m_string)[m_offset + lookaheadOffset];
     return result ? result : 0xFFFD;
 }
 
 void CSSTokenizerInputStream::pushBack(UChar cc)
 {
     --m_offset;
     ASSERT(nextInputChar() == cc);
 }
 
+void CSSTokenizerInputStream::advanceUntilNonWhitespace()
+{
+    // Using HTML space here rather than CSS space since we don't do preprocessing
+    if (m_string->is8Bit()) {
+        const LChar* characters = m_string->characters8();
+        while (m_offset < m_stringLength && isHTMLSpace(characters[m_offset]))
+            ++m_offset;
+    } else {
+        const UChar* characters = m_string->characters16();
+        while (m_offset < m_stringLength && isHTMLSpace(characters[m_offset]))
+            ++m_offset;
+    }
+}
+
 double CSSTokenizerInputStream::getDouble(unsigned start, unsigned end)
 {
     ASSERT(start <= end && ((m_offset + end) <= m_stringLength));
     bool isResultOK = false;
     double result = 0.0;
     if (start < end) {
         if (m_string->is8Bit())
             result = charactersToDouble(m_string->characters8() + m_offset + start, end - start, &isResultOK);
         else
             result = charactersToDouble(m_string->characters16() + m_offset + start, end - start, &isResultOK);
     }
     // FIXME: It looks like callers ensure we have a valid number
     return isResultOK ? result : 0.0;
 }
 
 StringView CSSTokenizerInputStream::rangeAt(unsigned start, unsigned length) const
 {
     ASSERT(start + length <= m_stringLength);
     return StringView(m_string.get(), start, length);
 }
 
 } // namespace blink