SmallStrings.h revision 2fc2651226baac27029e38c9d6ef883fa32084db 
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 "WriteBarrier.h"
31#include <wtf/FixedArray.h>
32#include <wtf/OwnPtr.h>
33
34namespace JSC {
35
36    class JSGlobalData;
37    class JSString;
38    class MarkStack;
39    class SmallStringsStorage;
40
41    class SmallStrings {
42        WTF_MAKE_NONCOPYABLE(SmallStrings); WTF_MAKE_FAST_ALLOCATED;
43    public:
44        SmallStrings();
45        ~SmallStrings();
46
47        JSString* emptyString(JSGlobalData* globalData)
48        {
49            if (!m_emptyString)
50                createEmptyString(globalData);
51            return m_emptyString.get();
52        }
53        JSString* singleCharacterString(JSGlobalData* globalData, unsigned char character)
54        {
55            if (!m_singleCharacterStrings[character])
56                createSingleCharacterString(globalData, character);
57            return m_singleCharacterStrings[character].get();
58        }
59
60        StringImpl* singleCharacterStringRep(unsigned char character);
61
62        void markChildren(MarkStack&);
63        void clear();
64
65        unsigned count() const;
66#if ENABLE(JIT)
67        JSCell** singleCharacterStrings() { return m_singleCharacterStrings[0].slot(); }
68#endif
69    private:
70        void createEmptyString(JSGlobalData*);
71        void createSingleCharacterString(JSGlobalData*, unsigned char);
72
73        DeprecatedPtr<JSString> m_emptyString;
74        FixedArray<DeprecatedPtr<JSString>, 0x100> m_singleCharacterStrings;
75        OwnPtr<SmallStringsStorage> m_storage;
76    };
77
78} // namespace JSC
79
80#endif // SmallStrings_h
81