projects / apple / javascriptcore.git / blame
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|---|---|---|
| 9dae56ea A |
1 | /* |
| 2 | * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. 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 PropertyMapHashTable_h | |
| 22 | #define PropertyMapHashTable_h | |
| 23 | ||
| 24 | #include "UString.h" | |
| 25 | #include <wtf/Vector.h> | |
| 26 | ||
| 27 | namespace JSC { | |
| 28 | ||
| 29 | struct PropertyMapEntry { | |
| 30 | UString::Rep* key; | |
| 31 | unsigned offset; | |
| 32 | unsigned attributes; | |
| ba379fdc | 33 | JSCell* specificValue; |
| 9dae56ea A |
34 | unsigned index; |
| 35 | ||
| ba379fdc | 36 | PropertyMapEntry(UString::Rep* key, unsigned attributes, JSCell* specificValue) |
| 9dae56ea A |
37 | : key(key) |
| 38 | , offset(0) | |
| 39 | , attributes(attributes) | |
| ba379fdc | 40 | , specificValue(specificValue) |
| 9dae56ea A |
41 | , index(0) |
| 42 | { | |
| 43 | } | |
| 44 | ||
| ba379fdc | 45 | PropertyMapEntry(UString::Rep* key, unsigned offset, unsigned attributes, JSCell* specificValue, unsigned index) |
| 9dae56ea A |
46 | : key(key) |
| 47 | , offset(offset) | |
| 48 | , attributes(attributes) | |
| ba379fdc | 49 | , specificValue(specificValue) |
| 9dae56ea A |
50 | , index(index) |
| 51 | { | |
| 52 | } | |
| 53 | }; | |
| 54 | ||
| 55 | // lastIndexUsed is an ever-increasing index used to identify the order items | |
| 56 | // were inserted into the property map. It's required that getEnumerablePropertyNames | |
| 57 | // return the properties in the order they were added for compatibility with other | |
| 58 | // browsers' JavaScript implementations. | |
| 59 | struct PropertyMapHashTable { | |
| 60 | unsigned sizeMask; | |
| 61 | unsigned size; | |
| 62 | unsigned keyCount; | |
| 63 | unsigned deletedSentinelCount; | |
| 64 | unsigned lastIndexUsed; | |
| 65 | Vector<unsigned>* deletedOffsets; | |
| 66 | unsigned entryIndices[1]; | |
| 67 | ||
| 68 | PropertyMapEntry* entries() | |
| 69 | { | |
| 70 | // The entries vector comes after the indices vector. | |
| 71 | // The 0th item in the entries vector is not really used; it has to | |
| 72 | // have a 0 in its key to allow the hash table lookup to handle deleted | |
| 73 | // sentinels without any special-case code, but the other fields are unused. | |
| 74 | return reinterpret_cast<PropertyMapEntry*>(&entryIndices[size]); | |
| 75 | } | |
| 76 | ||
| 77 | static size_t allocationSize(unsigned size) | |
| 78 | { | |
| 79 | // We never let a hash table get more than half full, | |
| 80 | // So the number of indices we need is the size of the hash table. | |
| 81 | // But the number of entries is half that (plus one for the deleted sentinel). | |
| 82 | return sizeof(PropertyMapHashTable) | |
| 83 | + (size - 1) * sizeof(unsigned) | |
| 84 | + (1 + size / 2) * sizeof(PropertyMapEntry); | |
| 85 | } | |
| 86 | }; | |
| 87 | ||
| 88 | } // namespace JSC | |
| 89 | ||
| 90 | #endif // PropertyMapHashTable_h |