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116 lines
2.3 KiB
C++
116 lines
2.3 KiB
C++
//
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// MemoryPool.h
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//
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// $Id: //poco/1.4/Foundation/include/Poco/MemoryPool.h#1 $
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//
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// Library: Foundation
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// Package: Core
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// Module: MemoryPool
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//
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// Definition of the MemoryPool class.
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//
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// Copyright (c) 2005-2006, Applied Informatics Software Engineering GmbH.
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// and Contributors.
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//
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// SPDX-License-Identifier: BSL-1.0
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//
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#ifndef Foundation_MemoryPool_INCLUDED
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#define Foundation_MemoryPool_INCLUDED
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#include "Poco/Foundation.h"
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#include "Poco/Mutex.h"
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#include <vector>
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#include <cstddef>
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namespace Poco {
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class Foundation_API MemoryPool
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/// A simple pool for fixed-size memory blocks.
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///
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/// The main purpose of this class is to speed-up
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/// memory allocations, as well as to reduce memory
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/// fragmentation in situations where the same blocks
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/// are allocated all over again, such as in server
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/// applications.
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///
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/// All allocated blocks are retained for future use.
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/// A limit on the number of blocks can be specified.
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/// Blocks can be preallocated.
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{
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public:
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MemoryPool(std::size_t blockSize, int preAlloc = 0, int maxAlloc = 0);
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/// Creates a MemoryPool for blocks with the given blockSize.
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/// The number of blocks given in preAlloc are preallocated.
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~MemoryPool();
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void* get();
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/// Returns a memory block. If there are no more blocks
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/// in the pool, a new block will be allocated.
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///
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/// If maxAlloc blocks are already allocated, an
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/// OutOfMemoryException is thrown.
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void release(void* ptr);
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/// Releases a memory block and returns it to the pool.
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std::size_t blockSize() const;
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/// Returns the block size.
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int allocated() const;
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/// Returns the number of allocated blocks.
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int available() const;
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/// Returns the number of available blocks in the pool.
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private:
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MemoryPool();
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MemoryPool(const MemoryPool&);
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MemoryPool& operator = (const MemoryPool&);
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enum
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{
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BLOCK_RESERVE = 128
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};
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typedef std::vector<char*> BlockVec;
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std::size_t _blockSize;
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int _maxAlloc;
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int _allocated;
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BlockVec _blocks;
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FastMutex _mutex;
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};
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//
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// inlines
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//
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inline std::size_t MemoryPool::blockSize() const
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{
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return _blockSize;
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}
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inline int MemoryPool::allocated() const
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{
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return _allocated;
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}
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inline int MemoryPool::available() const
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{
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return (int) _blocks.size();
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}
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} // namespace Poco
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#endif // Foundation_MemoryPool_INCLUDED
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