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文件名:MemoryPool.h
类名: CMemoryPool
描述: 本内存池（静态）实现了固定大小内存块分配与释放，其中实现了O(1)时间复杂度Alloc与Free操作，不产生任何内存碎片和缝隙。
***************************************************************************************/
#ifndef _LHF_MEMORY_POOL_H_
#define _LHF_MEMORY_POOL_H_
#include <Windows.h>
namespace LHF_MEMORY_POOL
{
enum
{
MEMORY_DESC_SIZE = 8,
MEMORY_BLOCK_HEADER_SIZE = 4,
};
// 内存块信息结构
struct MEMORY_DESC
{
void* m_pMemoryAddr;
MEMORY_DESC* m_pNext;
MEMORY_DESC()
{
memset(this,0,sizeof(MEMORY_DESC));
}
};
// 内存块结构
struct MEMORY_BLOCK
{
MEMORY_DESC* m_pMemoryDesc;
char m_pMemory[1];
MEMORY_BLOCK()
{
memset(this,0,sizeof(MEMORY_BLOCK));
}
};
// 内存池类
class CMemoryPool
{
private:
// 链表访问控制
CRITICAL_SECTION m_csMemoryPool;
// 内存块信息结构链表头
MEMORY_DESC* m_pBaseDesc;
// 单位内存块空间大小
DWORD m_dwUnitBlockSize;
// 内存块数量
DWORD m_dwBlockNum;
// 内存块链表
void* m_pLinearMemoryPool;
// 内存块信息链表
void* m_pLinearDescPool;
bool InitializeMemoryBlockPool();
bool InitializeMemoryDescPool();
public:
CMemoryPool();
~CMemoryPool();
bool InitializeMemoryPool(DWORD dwUnitBlockSize,DWORD dwBlockNum);
void* Alloc();
void Free(void* pMemory);
};
}
#endif
#include "MemoryPool.h"
namespace LHF_MEMORY_POOL
{
CMemoryPool::CMemoryPool()
{
memset(this,0,sizeof(this));
InitializeCriticalSection(&m_csMemoryPool);
}
CMemoryPool::~CMemoryPool()
{
DeleteCriticalSection(&m_csMemoryPool);
if (m_pLinearDescPool)
{
delete [] m_pLinearDescPool;
m_pLinearDescPool = NULL;
}
if (m_pLinearMemoryPool)
{
delete [] m_pLinearMemoryPool;
m_pLinearMemoryPool = NULL;
}
if (m_pBaseDesc)
{
m_pBaseDesc = NULL;
}
}
bool CMemoryPool::InitializeMemoryPool(DWORD dwUnitBlockSize,DWORD dwBlockNum)
{
bool bResult = FALSE;
if (!dwBlockNum || !dwUnitBlockSize)
{
return bResult;
}
this->m_dwUnitBlockSize = dwUnitBlockSize;
this->m_dwBlockNum = dwBlockNum;
EnterCriticalSection(&m_csMemoryPool);
this->m_pLinearDescPool = new char[dwBlockNum * MEMORY_DESC_SIZE];
if (!this->m_pLinearDescPool)
{
return bResult;
}
memset(this->m_pLinearDescPool,0,sizeof(char)*(dwBlockNum * MEMORY_DESC_SIZE));
this->m_pLinearMemoryPool = new char[dwBlockNum * (MEMORY_BLOCK_HEADER_SIZE+dwUnitBlockSize)];
if (!this->m_pLinearMemoryPool)
{
return bResult;
}
memset(this->m_pLinearMemoryPool,0,
sizeof(char)*(dwBlockNum * (MEMORY_BLOCK_HEADER_SIZE+dwUnitBlockSize)));
bResult = this->InitializeMemoryDescPool();
if (!bResult)
{
return bResult;
}
bResult = this->InitializeMemoryBlockPool();
LeaveCriticalSection(&m_csMemoryPool);
return bResult;
}
// 形成链表
bool CMemoryPool::InitializeMemoryDescPool()
{
MEMORY_DESC *pDescList = (MEMORY_DESC *)this->m_pLinearDescPool;
if (!pDescList)
{
return FALSE;
}
EnterCriticalSection(&m_csMemoryPool);
for (DWORD i=0 ;i<this->m_dwBlockNum;i++)
{
// 如果是最后一个，就指向空
pDescList[i].m_pMemoryAddr = NULL;
if (i == m_dwBlockNum-1)
{
pDescList[i].m_pNext = NULL;
}
else
{
pDescList[i].m_pNext = &pDescList[i+1];
}
}
this->m_pBaseDesc = &pDescList[0];
this->m_pBaseDesc->m_pNext = pDescList[0].m_pNext;
LeaveCriticalSection(&m_csMemoryPool);
return TRUE;
}
// 将内存块与分配链表挂钩
bool CMemoryPool::InitializeMemoryBlockPool()
{
char *pBlockList = (char *)this->m_pLinearMemoryPool;
MEMORY_DESC *pDescList = (MEMORY_DESC *)this->m_pLinearDescPool;
if (!pDescList || !pBlockList)
{
return FALSE;
}
EnterCriticalSection(&m_csMemoryPool);
for (DWORD i=0; i<this->m_dwBlockNum; i++)
{
char *pTmp = pBlockList + (i*(m_dwUnitBlockSize + MEMORY_BLOCK_HEADER_SIZE));
((MEMORY_BLOCK *)pTmp)->m_pMemoryDesc = &pDescList[i];
pDescList[i].m_pMemoryAddr = ((MEMORY_BLOCK *)pTmp)->m_pMemory;
}
LeaveCriticalSection(&m_csMemoryPool);
return TRUE;
}
void* CMemoryPool::Alloc()
{
void *pResult = NULL;
EnterCriticalSection(&m_csMemoryPool);
if(m_pBaseDesc)
{
// 备份出结果
pResult = m_pBaseDesc->m_pMemoryAddr;
// 重新修改m_pBaseDesc的指向
if (m_pBaseDesc->m_pNext)
{
m_pBaseDesc = m_pBaseDesc->m_pNext;
}
else
{
m_pBaseDesc = NULL;
}
}
LeaveCriticalSection(&m_csMemoryPool);
return pResult;
}
void CMemoryPool::Free(void* pMemory)
{
if (!pMemory)
{
return;
}
memset(pMemory,0,sizeof(char)*m_dwUnitBlockSize);
char *pFree = (char*)pMemory;
char *pDesc = pFree-4 ;
MEMORY_BLOCK *pMemoryBlock = (MEMORY_BLOCK *)pDesc;
pMemoryBlock->m_pMemoryDesc->m_pNext = m_pBaseDesc;
m_pBaseDesc = pMemoryBlock->m_pMemoryDesc;
}
}
转载地址：http://blog.163.com/xuanmingzhiyou@yeah/blog/static/14247767620123139023740/
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