简单的内存池实现

#ifndef _MEMPOOL_H_
#define _MEMPOOL_H_
#include<iostream>
template<typename T>
class CMemPool{
private:
    CMemPool<T>* m_pFreeList;
public:
    enum{EAXPANSION = 32};
    CMemPool(unsigned int nItemCount = EAXPANSION){
        ExpandFreeList(nItemCount);
    }
    ~CMemPool(){
        CMemPool<T>* pNext = NULL;
        for(pNext = m_pFreeList;pNext!=NULL;pNext = m_pFreeList){
            m_pFreeList = m_pFreeList->m_pFreeList;
            delete[]  (char*)pNext;
        }
    }
    void* Alloc(size_t){
        if(m_pFreeList==NULL){
            ExpandFreeList();
        }
        std::cout<<"ALLOC called"<<std::endl;
        CMemPool<T>* phead = m_pFreeList;
        m_pFreeList = m_pFreeList->m_pFreeList;
        return phead;
    }
    void Free(void* p){
        CMemPool<T>* phead = static_cast<CMemPool<T>*>(p);
        phead->m_pFreeList = m_pFreeList;
        m_pFreeList = phead;
        std::cout<<"Free called"<<std::endl;
    }
protected:
    void ExpandFreeList(unsigned int nItemcount = EAXPANSION){
        unsigned int nSize = sizeof(T)>sizeof(CMemPool<T>*)?sizeof(T):sizeof(CMemPool<T>*);
        CMemPool<T>* plastItem = static_cast<CMemPool<T>*>(static_cast<void*> (new char[nSize]));
        m_pFreeList = plastItem;
        for(int i=0;i<nItemcount-1;i++){
            plastItem->m_pFreeList = static_cast<CMemPool<T>*>(static_cast<void*>(new char[nSize]));
            plastItem = plastItem->m_pFreeList;
        }
        plastItem->m_pFreeList = NULL;
    }
};
#endif

#include<iostream>
#include<Windows.h>
using namespace std;
#include "mempool.h"


class CTest{
public:
    int m;
    int n;
    void* operator new(size_t size){
        void* p = s_pool->Alloc(size);
        return p;
    }
    void operator delete(void* p){
        s_pool->Free(p);
        return;
    }
    static void NewPool(){
        s_pool = new CMemPool<CTest>;
    }
    static void DelPool(){
        delete s_pool;
        return;
    }
    static CMemPool<CTest>* s_pool;
};
CMemPool<CTest>* CTest::s_pool=NULL;

void TestFun(){
    int i;
    const int nLoop = 10;
    const int nCount = 10;
   
    for(int j = 0; j<nLoop; ++j)
    {
        typedef CTest* LPTest;
        LPTest arData[nCount];
        for(i=0;i <nCount; ++i)
        {
            arData[i] = new CTest;
        }

        for(i=0;i <nCount; ++i)
        {
            delete arData[i];
        }
    }
}

int main(int argc, char* argv[])
{
    {
        unsigned int dwStartTickCount = GetTickCount();

        CTest::NewPool();

        TestFun();
       
        CTest::DelPool();
       
        cout << "total cost" << GetTickCount() - dwStartTickCount << endl;
    }
    system("pause");

    return 0;
}

转：http://www.2cto.com/kf/201205/130457.html