關注記憶體 提高軟體效能(2)

還有一種就是定義一個基類.裡面實現new,delete操作符,然後以後所有的類從該類派生,自動繼承基類的new,delete的實現.這種方法容易產生記憶體片段.My Code實現如下.下面的代碼還存在很多問題.暫時先放上去吧.

版本3.

#include<iostream>

#include <list>

#include <algorithm>

using namespace std;

class memorypool//該類的執行個體只允許出現一次.我用到了singleton模式.

{

public:

       static memorypool* Instance()

       {

              if(_instance == 0)

                     _instance = new memorypool;

              return _instance;

       }

       void Add( void * p)

       {

              lpMemlist->push_back(p);

       }

       void Del(const void* p)

       {

              list<void*>::iterator ite = find(lpMemlist->begin(),lpMemlist->end(),p);

              lpMemlist->erase(ite);

       }

       void clear()

       { 

        list<void*>::iterator it =lpMemlist->begin();

      

        while(!lpMemList->empty())

           delete (*it++);

         

              lpMemlist->clear();

       }

      

       protected:

       memorypool();

private:

       static memorypool* _instance;

       static list<void*>* lpMemlist;//作為池的資料結構

};

memorypool* memorypool::_instance = 0;

list<void*>* memorypool::lpMemlist = 0;

memorypool::memorypool()

{

       lpMemlist = new list<void*>;

      

       cout<<"list now has : " << lpMemlist->size() << endl;

}

 

///////////////////////////////////////////////////////////////////////////////////

class CBase

{

public:

       CBase() {

                    memorypool::Instance();

       }

       void* operator new(size_t size)

       {

              void *p = malloc(size);

              memorypool::Instance()->Add(p);

              return p;

 

       }

       void operator delete(void* p)

       {   delete p;

              memorypool::Instance()->Del(p);

       }

       ~CBase() { memorypool::Instance()->clear(); cout<<"base dtor/n";

       }

private:

       //static memorypool*

       //int nLeft;

      

};

class myclass :public CBase

{

public:

       myclass() { cout << "myclass ctor/n";

       }

};

class myclass2:public CBase

{

public:

       myclass2() { cout<<"myclass2 ctor/n";

       }

};

 

void testfun()

{      

              myclass* p = new myclass;

              myclass2* p2 =new myclass2;

              memorypool::Instance()->clear();

}

void main()

{

 

       testfun();

 

 

 

}

上面的幾種想法只是我想實現一下所謂的gc,感覺還是智能指標效果最好.其它幾個版本我只是想類比一下,驗證我自己的想法而已.代碼中肯定有錯誤的地方.不要被指責得一無是處就好.