c++对象池使用

//
//  ObjectPool.h
//  DragonBall
//
//  Created by user on 13-8-22.
//
//

#include <iostream>
#include <vector>
#include "cocos2d.h"
#include <algorithm>
using namespace std;
using namespace cocos2d;

template <typename T>
class ObjectPool{
public:

    ObjectPool(int initSize):m_initSize(initSize)
    {
        CCAssert(m_initSize >= 4, "m_initSize should >= 4");
        allocate(initSize);
    };


    virtual ~ObjectPool()
    {
        for_each(m_usedList.begin(), m_usedList.end(), freeObject);
        for_each(m_freeList.begin(), m_freeList.end(), freeObject);
    }

    // 请求一个对象
    T* request(){

        //先检查空闲里面是否为空
        if (m_freeList.size() == 0) {
            allocate(m_initSize/2);
        }

        T* t = m_freeList[0];
        m_freeList.erase(m_freeList.begin());
        m_usedList.push_back(t);
        return t;
    };


    // 放回一个对象到池里面
    void putback(T* t)
    {
        for (int i = 0; i < m_usedList.size(); ++i) {
            if (t == m_usedList[i]) {
                //找到此对象
                m_usedList.erase(m_usedList.begin() + i);
                m_freeList.push_back(t);return;
            }
        }
    }


    //为了避免内存的不断增长，需要保持空间
    void garbage()
    {
        //打印下大小
        CCLog("m_usedList.size:%d",m_usedList.size());
        CCLog("m_freeList.size:%d",m_freeList.size());

        //如果空余的多余20则删除到初始化个数
        if (m_freeList.size() > m_initSize) {

            typename vector<T*>::iterator it = m_freeList.begin();
            int pIndex = 0;
            while (it != m_freeList.end()) {

                if (pIndex > m_initSize) {
                    T* t = (*it);
                    m_freeList.erase(it);
                    freeObject(t);
                    --it;
                }

                ++pIndex;
                ++it;
            }
        }
    }

private:

    // 分配size个空间
    void allocate(int size)
    {
        for (int i = 0; i < size; ++i) {
            T* t = new T;
            m_freeList.push_back(t);
        }
    }

    static void freeObject(void* p)
    {
        T* t = (T*)p;
        Ref* temp = (Ref*)t;
        log("temp.ref : %d",temp->getReferenceCount());
        delete t;
    }
private:


    // 使用两个list一个用来放已经使用的,一个用来放未使用的
    vector<T*> m_freeList;
    vector<T*> m_usedList;

    // 初始容量
    int m_initSize;

};

使用的时候 先实例化

ObjectPool<T> * objectPool = new ObjectPool<T>(size);
   auto pRet;
   if(objectPool->request()){
       pRet = objectPool->request();
   }
   else{
      pRet = new T() ;
   }

pRet->remove();
objectPool->putBack(T);

原文链接: https://www.cnblogs.com/minwei/p/4505547.html

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