poco/Foundation/include/Poco/MemoryPool.h

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//
// MemoryPool.h
//
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// $Id: //poco/svn/Foundation/include/Poco/MemoryPool.h#2 $
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//
// Library: Foundation
// Package: Core
// Module: MemoryPool
//
// Definition of the MemoryPool class.
//
// Copyright (c) 2005-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
//
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//
#ifndef Foundation_MemoryPool_INCLUDED
#define Foundation_MemoryPool_INCLUDED
#include "Poco/Foundation.h"
#include "Poco/Mutex.h"
#include <vector>
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#include <cstddef>
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namespace Poco {
class Foundation_API MemoryPool
/// A simple pool for fixed-size memory blocks.
///
/// The main purpose of this class is to speed-up
/// memory allocations, as well as to reduce memory
/// fragmentation in situations where the same blocks
/// are allocated all over again, such as in server
/// applications.
///
/// All allocated blocks are retained for future use.
/// A limit on the number of blocks can be specified.
/// Blocks can be preallocated.
{
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.
/// The number of blocks given in preAlloc are preallocated.
~MemoryPool();
void* get();
/// Returns a memory block. If there are no more blocks
/// in the pool, a new block will be allocated.
///
/// If maxAlloc blocks are already allocated, an
/// OutOfMemoryException is thrown.
void release(void* ptr);
/// 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.
int allocated() const;
/// Returns the number of allocated blocks.
int available() const;
/// Returns the number of available blocks in the pool.
private:
MemoryPool();
MemoryPool(const MemoryPool&);
MemoryPool& operator = (const MemoryPool&);
enum
{
BLOCK_RESERVE = 128
};
typedef std::vector<char*> BlockVec;
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std::size_t _blockSize;
int _maxAlloc;
int _allocated;
BlockVec _blocks;
FastMutex _mutex;
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};
//
// inlines
//
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inline std::size_t MemoryPool::blockSize() const
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{
return _blockSize;
}
inline int MemoryPool::allocated() const
{
return _allocated;
}
inline int MemoryPool::available() const
{
return (int) _blocks.size();
}
} // namespace Poco
#endif // Foundation_MemoryPool_INCLUDED