runtime/SmallStrings.h

   1 /*
   2  * Copyright (C) 2008, 2009 Apple Inc. All Rights Reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #ifndef SmallStrings_h
  27 #define SmallStrings_h
  28
  29 #include "UString.h"
  30 #include <wtf/OwnPtr.h>
  31
  32 namespace JSC {
  33
  34     class JSGlobalData;
  35     class JSString;
  36     class MarkStack;
  37     class SmallStringsStorage;
  38
  39     class SmallStrings : public Noncopyable {
  40     public:
  41         SmallStrings();
  42         ~SmallStrings();
  43
  44         JSString* emptyString(JSGlobalData* globalData)
  45         {
  46             if (!m_emptyString)
  47                 createEmptyString(globalData);
  48             return m_emptyString;
  49         }
  50         JSString* singleCharacterString(JSGlobalData* globalData, unsigned char character)
  51         {
  52             if (!m_singleCharacterStrings[character])
  53                 createSingleCharacterString(globalData, character);
  54             return m_singleCharacterStrings[character];
  55         }
  56
  57         UString::Rep* singleCharacterStringRep(unsigned char character);
  58
  59         void markChildren(MarkStack&);
  60         void clear();
  61
  62         unsigned count() const;
  63 #if ENABLE(JIT)
  64         JSString** singleCharacterStrings() { return m_singleCharacterStrings; }
  65 #endif
  66     private:
  67         void createEmptyString(JSGlobalData*);
  68         void createSingleCharacterString(JSGlobalData*, unsigned char);
  69
  70         JSString* m_emptyString;
  71         JSString* m_singleCharacterStrings[0x100];
  72         OwnPtr<SmallStringsStorage> m_storage;
  73     };
  74
  75 } // namespace JSC
  76
  77 #endif // SmallStrings_h