// CHchFixLenMemPool.h
#pragma  once
#ifndef __CHchFixLenMemPool_H__
#define __CHchFixLenMemPool_H__
#include <exception>
#include <new>typedef struct __HchFixLenMemPoolLinkNode
{__HchFixLenMemPoolLinkNode *m_next;
}SHchFixLenMemPoolLinkNode;class CHchFixLenMemPool
{
public:CHchFixLenMemPool(size_t nFixLen, size_t nExpectObjectCnt = 0){ if ( nFixLen < (sizeof(void *) > sizeof(size_t) ? sizeof(void *) : sizeof(size_t)) ){throw std::exception("nFixLen < max(sizeof(void *), sizeof(size_t))");}//必须对齐，不然有可能出现内存访问异常m_nFixLen = (nFixLen + sizeof(int) - 1) & ~(sizeof(int) - 1);m_nExpectObjectCnt = nExpectObjectCnt;if (m_nExpectObjectCnt < 1024){m_nExpectObjectCnt = 1024;}m_allocSpaceLink = m_freeSpaceLink = NULL;allocFromSystem();}~CHchFixLenMemPool(){//遍历链表节点while (m_allocSpaceLink){SHchFixLenMemPoolLinkNode *pNext = m_allocSpaceLink->m_next;delete [](void *)m_allocSpaceLink;m_allocSpaceLink = pNext;}}void *alloc(){//如果存在已回收的空间，则直接分配出去if (m_freeSpaceLink != NULL){void *p = m_freeSpaceLink;m_freeSpaceLink = m_freeSpaceLink->m_next;return p;}//不然需要从m_allocSpaceLink里面切一块出来char *pRetSpace = m_currAllocSpace; //pRetSpace指向待返回的空间//如果上次new出来的内存还没分配完，则直接分配即可if (m_nLeft != 0){--m_nLeft;m_currAllocSpace += m_nFixLen;return pRetSpace;}//当前new出来的空间空间全部分配完 则需要重新向系统申请内存
        allocFromSystem();//这段跟前面分配逻辑是一样的//考虑到cpu流水线预测，刻意这样重复写代码 pRetSpace = m_currAllocSpace;--m_nLeft;m_currAllocSpace += m_nFixLen;return pRetSpace;}void free(void *pSpace){if (pSpace == NULL){return;}//如果回收空间链表为空，则直接修改m_allocSpaceLinke即可SHchFixLenMemPoolLinkNode *p = (SHchFixLenMemPoolLinkNode *)pSpace;if (m_allocSpaceLink == NULL){m_allocSpaceLink = p;m_allocSpaceLink->m_next = NULL;return;}//否则将当前空间插到链表头p->m_next = m_freeSpaceLink;m_freeSpaceLink = p;return;}private://从系统分配内存void allocFromSystem(){SHchFixLenMemPoolLinkNode *pNextLink = m_allocSpaceLink;//new失败会抛异常，不需要考虑m_allocSpaceLink = (SHchFixLenMemPoolLinkNode *)new char[sizeof(SHchFixLenMemPoolLinkNode) + m_nFixLen * m_nExpectObjectCnt];m_allocSpaceLink->m_next = pNextLink;m_nLeft = m_nExpectObjectCnt;m_currAllocSpace = ((char *)m_allocSpaceLink) + sizeof(SHchFixLenMemPoolLinkNode);}size_t m_nFixLen; //内存池定长size_t m_nLeft; //已申请未分配个数size_t m_nExpectObjectCnt; //每次申请多少个定长的空间//当前可分配的空间指针char *m_currAllocSpace;//回收空间链表 m_next指向下一个已回收空间SHchFixLenMemPoolLinkNode *m_freeSpaceLink;//已向系统申请的空间链表//链表中每个节点均指向new返回的指针//m_next指向下一个已向申请空间SHchFixLenMemPoolLinkNode *m_allocSpaceLink;
};template<typename  T>
T *newClassFromPool(CHchFixLenMemPool& objPool, const T& other)
{T *pState = (T *)objPool.alloc();new(pState) T(other);return pState;
}template<typename  T, typename  T1>
T *newClassFromPool(CHchFixLenMemPool& objPool, const T1& param)
{T *pState = (T *)objPool.alloc();new(pState) T(param);return pState;
}template<typename  T>
T *newClassFromPool(CHchFixLenMemPool& objPool)
{T *pState = (T *)objPool.alloc();new(pState) T();return pState;
}template<class T>
void deleteClassFromPool(CHchFixLenMemPool& objPool, T * pState)
{pState->~T();objPool.free(pState);
}#ifdef __POP_NEW_FLAG__
#pragma pop_macro("new")
#endif#endif

// testObjPool.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include "CHchFixLenMemPool.h"
#ifdef WIN32
#include <Windows.h>
#endif
#include <stdio.h>class CSimpleBuffer
{
public:CSimpleBuffer(size_t size = 32){m_memSize = size;m_pMem = new char[m_memSize];}CSimpleBuffer(const CSimpleBuffer& other){m_memSize = other.m_memSize;m_pMem = new char[m_memSize];memcpy(m_pMem, other.m_pMem, m_memSize);}char *getMem(){return m_pMem;}size_t getMemSize(){return m_memSize;}~CSimpleBuffer(){delete []m_pMem;}
private:size_t m_memSize;char *m_pMem;
};#ifdef WIN32class CMyTiming
{
public:CMyTiming(){m_startFlag = false;}bool startTiming() //开始计时
    {if (m_startFlag){return false;}m_startFlag = true;QueryPerformanceFrequency(&m_litmp); /*获得时钟频率*/ m_dff = m_litmp.QuadPart;QueryPerformanceCounter(&m_litmp); /*获得初始值*/ m_qtBeg = m_litmp.QuadPart;return true;}double getTiming() //获得当前消耗时间
    {if (!m_startFlag){return -1;}QueryPerformanceCounter(&m_litmp); /*获得终止值*/ m_qtEnd = m_litmp.QuadPart;m_dfm = (m_qtEnd - m_qtBeg);m_dft = ((double) m_dfm) / m_dff; /*获得对应的时间值*/return m_dft;}void endTiming() //停止计时
    {m_startFlag = false;}
private:bool m_startFlag;LARGE_INTEGER m_litmp;LONGLONG m_qtBeg, m_qtEnd, m_dff, m_dfm;double m_dft;
};
#endifint _tmain(int argc, _TCHAR* argv[])
{const int nTimes = 209600;const int n = 8000;CSimpleBuffer *pArray[nTimes];CMyTiming runTimeInfo;printf("total new times %d\n", nTimes * n);runTimeInfo.startTiming();for (int i = 0; i < n * nTimes; i++){int nPos =  i / n;pArray[nPos] = new CSimpleBuffer(64);pArray[nPos]->getMem()[0] = '\0';if (i % n != (n - 1)) delete pArray[nPos];}for (int i = 0; i < nTimes; i++){int nPos =  i / n;strcpy(pArray[nPos]->getMem(), "hell8ffff                                  fffff");pArray[nPos]->getMem()[i % 64] = '2';pArray[nPos]->getMem()[i % 32] =  i;if (i % n == (n - 1)) delete pArray[nPos];}printf("sec1 %.4f\n", runTimeInfo.getTiming());runTimeInfo.endTiming();runTimeInfo.startTiming();CHchFixLenMemPool objPool(sizeof(CSimpleBuffer), 8096);for (int i = 0; i < n * nTimes; i++){int nPos =  i / n;pArray[nPos] = newClassFromPool<CSimpleBuffer, size_t>(objPool, 64);pArray[nPos]->getMem()[0] = '\0';if (i % n != (n - 1)) deleteClassFromPool(objPool, pArray[nPos]);}for (int i = 0; i < nTimes; i++){int nPos =  i / n;strcpy(pArray[nPos]->getMem(), "hell8ffff                                  fffff");pArray[nPos]->getMem()[i % 64] = '2';pArray[nPos]->getMem()[i % 32] =  i;if (i % n == (n - 1)) deleteClassFromPool(objPool, pArray[nPos]);}printf("sec2 %.4f\n", runTimeInfo.getTiming());return 0;
}

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