1/*
2 * Copyright (C) 2013 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. AND ITS CONTRIBUTORS ``AS IS''
14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
23 * THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#ifndef StructureIDTable_h
27#define StructureIDTable_h
28
29#include "UnusedPointer.h"
30#include <wtf/Vector.h>
31
32namespace JSC {
33
34class Structure;
35
36#if USE(JSVALUE64)
37typedef uint32_t StructureID;
38#else
39typedef Structure* StructureID;
40#endif
41
42class StructureIDTable {
43 friend class LLIntOffsetsExtractor;
44public:
45 StructureIDTable();
46
47 void** base() { return reinterpret_cast<void**>(&m_table); }
48
49 Structure* get(StructureID);
50 void deallocateID(Structure*, StructureID);
51 StructureID allocateID(Structure*);
52
53 void flushOldTables();
54
55private:
56 void resize(size_t newCapacity);
57
58 union StructureOrOffset {
59 WTF_MAKE_FAST_ALLOCATED;
60 public:
61 Structure* structure;
62 StructureID offset;
63 };
64
65 StructureOrOffset* table() const { return m_table.get(); }
66
67 static const size_t s_initialSize = 256;
68
69 Vector<std::unique_ptr<StructureOrOffset[]>> m_oldTables;
70
71 uint32_t m_firstFreeOffset;
72 std::unique_ptr<StructureOrOffset[]> m_table;
73
74 size_t m_size;
75 size_t m_capacity;
76
77#if USE(JSVALUE64)
78 static const StructureID s_unusedID = unusedPointer;
79#endif
80};
81
82inline Structure* StructureIDTable::get(StructureID structureID)
83{
84#if USE(JSVALUE64)
85 ASSERT_WITH_SECURITY_IMPLICATION(structureID && structureID < m_capacity);
86 return table()[structureID].structure;
87#else
88 return structureID;
89#endif
90}
91
92} // namespace JSC
93
94#endif // StructureIDTable_h
95