memorypool.cpp.svn-base

很好用的网络封装库,不熟悉网络编程的人也可以使用。使用风格良好的标准c++编写。

//
// MemoryPool.cpp
//
// $Id: //poco/1.3/Foundation/src/MemoryPool.cpp#2 $
//
// Library: Foundation
// Package: Core
// Module:  MemoryPool
//
// 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.
//


#include "Poco/MemoryPool.h"
#include "Poco/Exception.h"


namespace Poco {


MemoryPool::MemoryPool(std::size_t blockSize, int preAlloc, int maxAlloc):
	_blockSize(blockSize),
	_maxAlloc(maxAlloc),
	_allocated(preAlloc)
{
	poco_assert (maxAlloc == 0 || maxAlloc >= preAlloc);
	poco_assert (preAlloc >= 0 && maxAlloc >= 0);

	int r = BLOCK_RESERVE;
	if (preAlloc > r)
		r = preAlloc;
	if (maxAlloc > 0 && maxAlloc < r)
		r = maxAlloc;
	_blocks.reserve(r);
	for (int i = 0; i < preAlloc; ++i)
	{
		_blocks.push_back(new char[_blockSize]);
	}
}

	
MemoryPool::~MemoryPool()
{
	for (BlockVec::iterator it = _blocks.begin(); it != _blocks.end(); ++it)
	{
		delete [] *it;
	}
}


void* MemoryPool::get()
{
	FastMutex::ScopedLock lock(_mutex);
	
	if (_blocks.empty())
	{
		if (_maxAlloc == 0 || _allocated < _maxAlloc)
		{
			++_allocated;
			return new char[_blockSize];
		}
		else throw OutOfMemoryException("MemoryPool exhausted");
	}
	else
	{
		char* ptr = _blocks.back();
		_blocks.pop_back();
		return ptr;
	}
}

	
void MemoryPool::release(void* ptr)
{
	FastMutex::ScopedLock lock(_mutex);
	
	_blocks.push_back(reinterpret_cast<char*>(ptr));
}


} // namespace Poco