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/*
* Copyright (C) 2013 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "StructureIDTable.h"
#include <limits.h>
#include <wtf/Atomics.h>
#include <wtf/DataLog.h>
namespace JSC {
StructureIDTable::StructureIDTable()
: m_firstFreeOffset(0)
, m_table(std::make_unique<StructureOrOffset[]>(s_initialSize))
, m_size(0)
, m_capacity(s_initialSize)
{
// We pre-allocate the first offset so that the null Structure
// can still be represented as the StructureID '0'.
allocateID(0);
}
void StructureIDTable::resize(size_t newCapacity)
{
// Create the new table.
auto newTable = std::make_unique<StructureOrOffset[]>(newCapacity);
// Copy the contents of the old table to the new table.
memcpy(newTable.get(), table(), m_capacity * sizeof(StructureOrOffset));
// Store fence to make sure we've copied everything before doing the swap.
WTF::storeStoreFence();
// Swap the old and new tables.
swap(m_table, newTable);
// Put the old table (now labeled as new) into the list of old tables.
m_oldTables.append(WTFMove(newTable));
// Update the capacity.
m_capacity = newCapacity;
}
void StructureIDTable::flushOldTables()
{
m_oldTables.clear();
}
StructureID StructureIDTable::allocateID(Structure* structure)
{
#if USE(JSVALUE64)
if (!m_firstFreeOffset) {
RELEASE_ASSERT(m_capacity <= UINT_MAX);
if (m_size == m_capacity)
resize(m_capacity * 2);
ASSERT(m_size < m_capacity);
StructureOrOffset newEntry;
newEntry.structure = structure;
if (m_size == s_unusedID) {
m_size++;
return allocateID(structure);
}
StructureID result = m_size;
table()[result] = newEntry;
m_size++;
return result;
}
ASSERT(m_firstFreeOffset != s_unusedID);
StructureID result = m_firstFreeOffset;
m_firstFreeOffset = table()[m_firstFreeOffset].offset;
table()[result].structure = structure;
return result;
#else
return structure;
#endif
}
void StructureIDTable::deallocateID(Structure* structure, StructureID structureID)
{
#if USE(JSVALUE64)
ASSERT(structureID != s_unusedID);
RELEASE_ASSERT(table()[structureID].structure == structure);
table()[structureID].offset = m_firstFreeOffset;
m_firstFreeOffset = structureID;
#else
UNUSED_PARAM(structure);
UNUSED_PARAM(structureID);
#endif
}
} // namespace JSC
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