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      1 /*
      2  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
      3  *
      4  * This library is free software; you can redistribute it and/or
      5  * modify it under the terms of the GNU Library General Public
      6  * License as published by the Free Software Foundation; either
      7  * version 2 of the License, or (at your option) any later version.
      8  *
      9  * This library is distributed in the hope that it will be useful,
     10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
     11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     12  * Library General Public License for more details.
     13  *
     14  * You should have received a copy of the GNU Library General Public License
     15  * along with this library; see the file COPYING.LIB.  If not, write to
     16  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     17  * Boston, MA 02110-1301, USA.
     18  *
     19  */
     20 
     21 #ifndef SurrogatePairAwareTextIterator_h
     22 #define SurrogatePairAwareTextIterator_h
     23 
     24 #include "wtf/unicode/CharacterNames.h"
     25 #include "wtf/text/WTFString.h"
     26 
     27 namespace WebCore {
     28 
     29 class SurrogatePairAwareTextIterator {
     30 public:
     31     // The passed in UChar pointer starts at 'currentCharacter'. The iterator operatoes on the range [currentCharacter, lastCharacter].
     32     // 'endCharacter' denotes the maximum length of the UChar array, which might exceed 'lastCharacter'.
     33     SurrogatePairAwareTextIterator(const UChar*, int currentCharacter, int lastCharacter, int endCharacter);
     34 
     35     inline bool consume(UChar32& character, unsigned& clusterLength)
     36     {
     37         if (m_currentCharacter >= m_lastCharacter)
     38             return false;
     39 
     40         character = *m_characters;
     41         clusterLength = 1;
     42 
     43         if (character < HiraganaLetterSmallA)
     44             return true;
     45 
     46         return consumeSlowCase(character, clusterLength);
     47     }
     48 
     49     void advance(unsigned advanceLength)
     50     {
     51         m_characters += advanceLength;
     52         m_currentCharacter += advanceLength;
     53     }
     54 
     55     int currentCharacter() const { return m_currentCharacter; }
     56     const UChar* characters() const { return m_characters; }
     57 
     58 private:
     59     bool consumeSlowCase(UChar32&, unsigned&);
     60     UChar32 normalizeVoicingMarks();
     61 
     62     const UChar* m_characters;
     63     int m_currentCharacter;
     64     int m_lastCharacter;
     65     int m_endCharacter;
     66 };
     67 
     68 }
     69 
     70 #endif
     71