Remove SegmentedString::m_pushedChar{1,2} optimization

Source/platform/text/SegmentedString.cpp

 /*
     Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
 
     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Library General Public
     License as published by the Free Software Foundation; either
     version 2 of the License, or (at your option) any later version.
 
     This library is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     Library General Public License for more details.
 
     You should have received a copy of the GNU Library General Public License
     along with this library; see the file COPYING.LIB.  If not, write to
     the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     Boston, MA 02110-1301, USA.
 */
 
 #include "config.h"
 #include "platform/text/SegmentedString.h"
 
 namespace blink {
 
 unsigned SegmentedString::length() const
 {
     unsigned length = m_currentString.length();
-    if (m_pushedChar1) {
-        ++length;
-        if (m_pushedChar2)
-            ++length;
-    }
     if (isComposite()) {
         Deque<SegmentedSubstring>::const_iterator it = m_substrings.begin();
         Deque<SegmentedSubstring>::const_iterator e = m_substrings.end();
         for (; it != e; ++it)
             length += it->length();
     }
     return length;
 }
 
 void SegmentedString::setExcludeLineNumbers()
 {
     m_currentString.setExcludeLineNumbers();
     if (isComposite()) {
         Deque<SegmentedSubstring>::iterator it = m_substrings.begin();
         Deque<SegmentedSubstring>::iterator e = m_substrings.end();
         for (; it != e; ++it)
             it->setExcludeLineNumbers();
     }
 }
 
 void SegmentedString::clear()
 {
-    m_pushedChar1 = 0;
-    m_pushedChar2 = 0;
     m_currentChar = 0;
     m_currentString.clear();
     m_numberOfCharactersConsumedPriorToCurrentString = 0;
     m_numberOfCharactersConsumedPriorToCurrentLine = 0;
     m_currentLine = 0;
     m_substrings.clear();
     m_closed = false;
     m_empty = true;
     m_fastPathFlags = NoFastPath;
     m_advanceFunc = &SegmentedString::advanceEmpty;
     m_advanceAndUpdateLineNumberFunc = &SegmentedString::advanceEmpty;
 }
 
 void SegmentedString::append(const SegmentedSubstring& s)
 {
     ASSERT(!m_closed);
     if (!s.length())
         return;
 
     if (!m_currentString.length()) {
         m_numberOfCharactersConsumedPriorToCurrentString += m_currentString.numberOfCharactersConsumed();
         m_currentString = s;
         updateAdvanceFunctionPointers();
     } else {
         m_substrings.append(s);
     }
     m_empty = false;
 }
 
+void SegmentedString::push(UChar c)
+{
+    ASSERT(c);
+    if (m_currentString.pushIfPossible(c)) {
+        m_currentChar = c;
+        return;
+    }
+
+    prepend(SegmentedString(String(&c, 1)));
+}
+
 void SegmentedString::prepend(const SegmentedSubstring& s)
 {
-    ASSERT(!escaped());
     ASSERT(!s.numberOfCharactersConsumed());
     if (!s.length())
         return;
 
     // FIXME: We're assuming that the prepend were originally consumed by
     //        this SegmentedString. We're also ASSERTing that s is a fresh
     //        SegmentedSubstring. These assumptions are sufficient for our
     //        current use, but we might need to handle the more elaborate
     //        cases in the future.
     m_numberOfCharactersConsumedPriorToCurrentString += m_currentString.numberOfCharactersConsumed();
@@ skipping 13 matching lines @@
 void SegmentedString::close()
 {
     // Closing a stream twice is likely a coding mistake.
     ASSERT(!m_closed);
     m_closed = true;
 }
 
 void SegmentedString::append(const SegmentedString& s)
 {
     ASSERT(!m_closed);
-    if (s.m_pushedChar1) {
-        Vector<UChar, 2> unconsumedData;
-        unconsumedData.append(s.m_pushedChar1);
-        if (s.m_pushedChar2)
-            unconsumedData.append(s.m_pushedChar2);
-        append(SegmentedSubstring(String(unconsumedData)));
-    }
 
     append(s.m_currentString);
     if (s.isComposite()) {
         Deque<SegmentedSubstring>::const_iterator it = s.m_substrings.begin();
         Deque<SegmentedSubstring>::const_iterator e = s.m_substrings.end();
         for (; it != e; ++it)
             append(*it);
     }
-    m_currentChar = m_pushedChar1 ? m_pushedChar1 : (m_currentString.length() ? m_currentString.getCurrentChar() : 0);
+    m_currentChar = m_currentString.length() ? m_currentString.getCurrentChar() : 0;
 }
 
 void SegmentedString::prepend(const SegmentedString& s)
 {
-    ASSERT(!escaped());
-    ASSERT(!s.escaped());
     if (s.isComposite()) {
         Deque<SegmentedSubstring>::const_reverse_iterator it = s.m_substrings.rbegin();
         Deque<SegmentedSubstring>::const_reverse_iterator e = s.m_substrings.rend();
         for (; it != e; ++it)
             prepend(*it);
     }
     prepend(s.m_currentString);
     m_currentChar = m_currentString.length() ? m_currentString.getCurrentChar() : 0;
 }
 
@@ skipping 12 matching lines @@
         m_empty = true;
         m_fastPathFlags = NoFastPath;
         m_advanceFunc = &SegmentedString::advanceEmpty;
         m_advanceAndUpdateLineNumberFunc = &SegmentedString::advanceEmpty;
     }
 }
 
 String SegmentedString::toString() const
 {
     StringBuilder result;
-    if (m_pushedChar1) {
-        result.append(m_pushedChar1);
-        if (m_pushedChar2)
-            result.append(m_pushedChar2);
-    }
     m_currentString.appendTo(result);
     if (isComposite()) {
         Deque<SegmentedSubstring>::const_iterator it = m_substrings.begin();
         Deque<SegmentedSubstring>::const_iterator e = m_substrings.end();
         for (; it != e; ++it)
             it->appendTo(result);
     }
     return result.toString();
 }
 
 void SegmentedString::advance(unsigned count, UChar* consumedCharacters)
 {
     ASSERT_WITH_SECURITY_IMPLICATION(count <= length());
     for (unsigned i = 0; i < count; ++i) {
         consumedCharacters[i] = currentChar();
         advance();
     }
 }
 
 void SegmentedString::advance8()
 {
-    ASSERT(!m_pushedChar1);
     decrementAndCheckLength();
     m_currentChar = m_currentString.incrementAndGetCurrentChar8();
 }
 
 void SegmentedString::advance16()
 {
-    ASSERT(!m_pushedChar1);
     decrementAndCheckLength();
     m_currentChar = m_currentString.incrementAndGetCurrentChar16();
 }
 
 void SegmentedString::advanceAndUpdateLineNumber8()
 {
-    ASSERT(!m_pushedChar1);
     ASSERT(m_currentString.getCurrentChar() == m_currentChar);
     if (m_currentChar == '\n') {
         ++m_currentLine;
         m_numberOfCharactersConsumedPriorToCurrentLine = numberOfCharactersConsumed() + 1;
     }
     decrementAndCheckLength();
     m_currentChar = m_currentString.incrementAndGetCurrentChar8();
 }
 
 void SegmentedString::advanceAndUpdateLineNumber16()
 {
-    ASSERT(!m_pushedChar1);
     ASSERT(m_currentString.getCurrentChar() == m_currentChar);
     if (m_currentChar == '\n') {
         ++m_currentLine;
         m_numberOfCharactersConsumedPriorToCurrentLine = numberOfCharactersConsumed() + 1;
     }
     decrementAndCheckLength();
     m_currentChar = m_currentString.incrementAndGetCurrentChar16();
 }
 
 void SegmentedString::advanceSlowCase()
 {
-    if (m_pushedChar1) {
-        m_pushedChar1 = m_pushedChar2;
-        m_pushedChar2 = 0;
-
-        if (m_pushedChar1) {
-            m_currentChar = m_pushedChar1;
-            return;
-        }
-
-        updateAdvanceFunctionPointers();
-    } else if (m_currentString.length()) {
+    if (m_currentString.length()) {
         m_currentString.decrementLength();
         if (!m_currentString.length())
             advanceSubstring();
     } else if (!isComposite()) {
         m_currentString.clear();
         m_empty = true;
         m_fastPathFlags = NoFastPath;
         m_advanceFunc = &SegmentedString::advanceEmpty;
         m_advanceAndUpdateLineNumberFunc = &SegmentedString::advanceEmpty;
     }
     m_currentChar = m_currentString.length() ? m_currentString.getCurrentChar() : 0;
 }
 
 void SegmentedString::advanceAndUpdateLineNumberSlowCase()
 {
-    if (m_pushedChar1) {
-        m_pushedChar1 = m_pushedChar2;
-        m_pushedChar2 = 0;
-
-        if (m_pushedChar1) {
-            m_currentChar = m_pushedChar1;
-            return;
-        }
-
-        updateAdvanceFunctionPointers();
-    } else if (m_currentString.length()) {
+    if (m_currentString.length()) {
         if (m_currentString.getCurrentChar() == '\n' && m_currentString.doNotExcludeLineNumbers()) {
             ++m_currentLine;
             // Plus 1 because numberOfCharactersConsumed value hasn't incremented yet; it does with length() decrement below.
             m_numberOfCharactersConsumedPriorToCurrentLine = numberOfCharactersConsumed() + 1;
         }
         m_currentString.decrementLength();
         if (!m_currentString.length())
             advanceSubstring();
         else
             m_currentString.incrementAndGetCurrentChar(); // Only need the ++
@@ skipping 32 matching lines @@
     return OrdinalNumber::fromZeroBasedInt(zeroBasedColumn);
 }
 
 void SegmentedString::setCurrentPosition(OrdinalNumber line, OrdinalNumber columnAftreProlog, int prologLength)
 {
     m_currentLine = line.zeroBasedInt();
     m_numberOfCharactersConsumedPriorToCurrentLine = numberOfCharactersConsumed() + prologLength - columnAftreProlog.zeroBasedInt();
 }
 
 }