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 HeapRootMarker;
37    class JSGlobalData;
38    class JSString;
39    class MarkStack;
40    class SmallStringsStorage;
41
42    static const unsigned maxSingleCharacterString = 0xFF;
43
44    class SmallStrings {
45        WTF_MAKE_NONCOPYABLE(SmallStrings);
46    public:
47        SmallStrings();
48        ~SmallStrings();
49
50        JSString* emptyString(JSGlobalData* globalData)
51        {
52            if (!m_emptyString)
53                createEmptyString(globalData);
54            return m_emptyString;
55        }
56
57        JSString* singleCharacterString(JSGlobalData* globalData, unsigned char character)
58        {
59            if (!m_singleCharacterStrings[character])
60                createSingleCharacterString(globalData, character);
61            return m_singleCharacterStrings[character];
62        }
63
64        StringImpl* singleCharacterStringRep(unsigned char character);
65
66        void markChildren(HeapRootMarker&);
67        void clear();
68
69        unsigned count() const;
70
71        JSString** singleCharacterStrings() { return &m_singleCharacterStrings[0]; }
72
73    private:
74        static const unsigned singleCharacterStringCount = maxSingleCharacterString + 1;
75
76        void createEmptyString(JSGlobalData*);
77        void createSingleCharacterString(JSGlobalData*, unsigned char);
78
79        JSString* m_emptyString;
80        JSString* m_singleCharacterStrings[singleCharacterStringCount];
81        OwnPtr<SmallStringsStorage> m_storage;
82    };
83
84} // namespace JSC
85
86#endif // SmallStrings_h
87