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/*
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* Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public License
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* along with this library; see the file COPYING.LIB. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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* Boston, MA 02110-1301, USA.
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*
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*/
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#ifndef PropertyMapHashTable_h
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#define PropertyMapHashTable_h
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#include "UString.h"
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#include <wtf/Vector.h>
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namespace JSC {
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struct PropertyMapEntry {
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UString::Rep* key;
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unsigned offset;
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unsigned attributes;
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JSCell* specificValue;
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unsigned index;
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PropertyMapEntry(UString::Rep* key, unsigned attributes, JSCell* specificValue)
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: key(key)
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, offset(0)
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, attributes(attributes)
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, specificValue(specificValue)
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, index(0)
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{
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}
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PropertyMapEntry(UString::Rep* key, unsigned offset, unsigned attributes, JSCell* specificValue, unsigned index)
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: key(key)
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, offset(offset)
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, attributes(attributes)
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, specificValue(specificValue)
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, index(index)
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{
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}
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};
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// lastIndexUsed is an ever-increasing index used to identify the order items
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// were inserted into the property map. It's required that getEnumerablePropertyNames
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// return the properties in the order they were added for compatibility with other
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// browsers' JavaScript implementations.
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struct PropertyMapHashTable {
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unsigned sizeMask;
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unsigned size;
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unsigned keyCount;
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unsigned deletedSentinelCount;
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unsigned anonymousSlotCount;
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unsigned lastIndexUsed;
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Vector<unsigned>* deletedOffsets;
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unsigned entryIndices[1];
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PropertyMapEntry* entries()
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{
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// The entries vector comes after the indices vector.
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// The 0th item in the entries vector is not really used; it has to
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// have a 0 in its key to allow the hash table lookup to handle deleted
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// sentinels without any special-case code, but the other fields are unused.
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return reinterpret_cast<PropertyMapEntry*>(&entryIndices[size]);
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}
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static size_t allocationSize(unsigned size)
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{
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// We never let a hash table get more than half full,
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// So the number of indices we need is the size of the hash table.
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// But the number of entries is half that (plus one for the deleted sentinel).
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return sizeof(PropertyMapHashTable)
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+ (size - 1) * sizeof(unsigned)
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+ (1 + size / 2) * sizeof(PropertyMapEntry);
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}
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};
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} // namespace JSC
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#endif // PropertyMapHashTable_h
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