mirror of
https://github.com/darlinghq/darling-WTF.git
synced 2024-11-23 11:59:47 +00:00
97 lines
2.7 KiB
C++
97 lines
2.7 KiB
C++
/*
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* Copyright (C) 2011 Apple Inc. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
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* THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef BlockStack_h
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#define BlockStack_h
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#include <wtf/Assertions.h>
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#include <wtf/FastMalloc.h>
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#include <wtf/Vector.h>
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namespace WTF {
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template <typename T> class BlockStack {
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public:
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static const size_t blockSize = 4096;
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static const size_t blockLength = blockSize / sizeof(T);
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BlockStack();
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~BlockStack();
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T* grow();
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void shrink(T*);
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const Vector<T*>& blocks();
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private:
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Vector<T*> m_blocks;
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T* m_spareBlock; // Used to avoid thrash at block boundaries.
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};
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template <typename T> BlockStack<T>::BlockStack()
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: m_spareBlock(0)
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{
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}
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template <typename T> BlockStack<T>::~BlockStack()
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{
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if (m_spareBlock)
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fastFree(m_spareBlock);
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for (size_t i = 0; i < m_blocks.size(); ++i)
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fastFree(m_blocks[i]);
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}
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template <typename T> inline const Vector<T*>& BlockStack<T>::blocks()
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{
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return m_blocks;
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}
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template <typename T> T* BlockStack<T>::grow()
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{
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T* block = m_spareBlock ? m_spareBlock : static_cast<T*>(fastMalloc(blockSize));
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m_spareBlock = 0;
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m_blocks.append(block);
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return block;
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}
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template <typename T> void BlockStack<T>::shrink(T* newEnd)
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{
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ASSERT(newEnd != m_blocks.last() + blockLength);
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m_spareBlock = m_blocks.last();
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m_blocks.removeLast();
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while (m_blocks.last() + blockLength != newEnd) {
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fastFree(m_blocks.last());
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m_blocks.removeLast();
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}
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}
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}
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using WTF::BlockStack;
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#endif
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