C++实现简单的内存池

来源：互联网发布：知乎中央民族大学舞蹈编辑：程序博客网时间：2024/06/05 11:19

没有考虑线程安全，只是简单的实现了内存池
功能：第一次先申请一大片内存，然后分成小块，每次分配给应用程序这小块内存，当内存不够了又继续向系统申请一大片内存
直接晒代码

MemPool.h

#include <iostream>template<typename T>class MemPool{public:    MemPool(){}    MemPool(T data) :data(data){}    //这两个函数编译器就默认处理成static函数    void *operator new(size_t size)    {        MemPool *pCur;        if (!pHead)//如果内存不够了，向系统申请内存        {            int allocsize = size * MEM_POOL_SIZE;            cout << "第" << ++count << "向系统申请了" << allocsize << "字节内存" << endl;            pHead = (MemPool*)new char[allocsize];            for (pCur = pHead; pCur < pHead + MEM_POOL_SIZE - 1;++pCur)                pCur->pNext = pCur + 1;            pCur->pNext = NULL;        }        pCur = pHead;        pHead = pHead->pNext;        return pCur;//这里只是把其中一片内存给用户了，用户并不能通过 ->pNext 得到下一片内存★★★★★    }    void operator delete(void *ptr)    {        cout << "MemPool delete" << endl;        if (!ptr) return;        MemPool *cur = (MemPool*)ptr;        cur->pNext = pHead;        pHead = cur;    }public:    MemPool *pNext;    static const unsigned int MEM_POOL_SIZE = 10;    static MemPool *pHead;    static int count;    T data;};template<typename T>static MemPool<T> *initNull(){    cout << "initNull" << endl;    return NULL;}template<typename T>MemPool<T> *MemPool<T>::pHead = initNull<T>();template<typename T>int MemPool<T>::count = 0;

Queue.h

#include "Mempool.h"template<typename T>class Queue{public:    Queue()    {        prear = pfirst = NULL;    }    ~Queue()    {        MemPool<T> *pcur = pfirst;        while (pcur != prear)        {            pfirst = pfirst->pNext;            delete pcur;            pcur = pfirst;        }    }    T front()    {        if (!pfirst)            return NULL;        return pfirst->data;    }    T back()    {        if (!prear)            return NULL;        return prear->data;    }    void push(const T &d)    {        /*prear = new MemPool<T>(d);        if (!pfirst)            pfirst = prear;*/        MemPool<T> *p = new MemPool<T>(d);        if (!prear)            prear = pfirst = p;        else        {            prear->pNext = p;            prear = p;        }    }    void pop()    {        if (pfirst == prear)        {            delete pfirst;            pfirst = prear = NULL;        }        else        {            MemPool<T> *pFree = pfirst;            pfirst = pfirst->pNext;            delete pFree;        }    }    bool empty()    {        if (prear == NULL && pfirst == NULL)            return true;        return false;    }private:    MemPool<T> *prear;    MemPool<T> *pfirst;};

main

#include "Queue.h"#include <queue>using namespace std;int main(){    Queue<int> q1;    queue<int> q2;    for (int i = 0; i < 22; i++)    {        q1.push(i);        q2.push(i);    }    while (!q1.empty())    {        cout << q1.front() << " ";        q1.pop();    }    while (!q2.empty())    {        cout << q2.front() << " ";        q2.pop();    }    cout << endl;    system("pause");    return 0;}

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