智能指正和强弱指针的实现

来源：互联网发布：mips linux gnu gcc 编辑：程序博客网时间：2024/06/06 12:46
#include <iostream>#include <map>#include <pthread.h>using namespace std;class maps_ptr{public:        static maps_ptr * getptr()        {                if(inst==NULL)                {                    inst=new maps_ptr();                }                return inst;        }        void addRef(void *mptr)        {            map<void *,int>::iterator it=a.find(mptr);            if(it!=a.end())            {                    it->second++;                    return ;            }            a.emplace(mptr,1);        }        void delRef(void *mptr)        {                map<void *,int>::iterator it=a.find(mptr);                if(it!=a.end())                {                        it->second--;                        if(it->second==0)                        {                                a.erase(it);                        }                }        }        int  getRef(void *mptr)        {            map<void *,int>::iterator it=a.find(mptr);            if(it!=a.end())            {                    return it->second;            }            return 0;        }private:        maps_ptr()        {};        static maps_ptr *inst;        map<void *,int> a;};maps_ptr* maps_ptr::inst=NULL;template <typename T>class Cweak;template <typename T>class smart_ptr{public:        smart_ptr(T* ptr=NULL):mptr(ptr)        {                if(mptr!=NULL)                {                    a->addRef(mptr);                }        };        ~smart_ptr()        {            a->delRef(mptr);            if(a->getRef(mptr)==0)            {                    delete mptr;            }        }        smart_ptr(const smart_ptr &src)        {                if(src.mptr!=NULL)                {                        mptr=src.mptr;                        a->addRef(mptr);                }                else                {                        mptr=NULL;                }        }        smart_ptr<T> (const Cweak<T> &src)        {            if(a->getRef(mptr)!=0)            {                    mptr=src.mptr;                    a->addRef(mptr);            }            else            {                    mptr=NULL;            }        }        smart_ptr<T>& operator =(const smart_ptr &src)        {                a->delRef(mptr);                if(a->getRef(mptr)==0)                {                        delete mptr;                }                mptr=src.mptr;                if(mptr!=NULL)                {                        a->addRef(mptr);                }                return *this;        }        T& operator *()        {                return *mptr;         }        T* operator ->()        {                return mptr;        }        operator void  *()//使用类型转换如果需要类型转换        {            if(a->getRef(mptr)>0)            {                    return mptr;            }            return NULL;        }private:        static maps_ptr *a;        T *mptr;        friend class Cweak<T>;};template<typename T>maps_ptr* smart_ptr<T>::a=maps_ptr::getptr();template <typename T>class Cweak{public:        friend class smart_ptr<T>;        Cweak(T *p=NULL):mptr(p){};        Cweak(const smart_ptr<T> &src)        {                //mptr=&*src;                mptr=src.mptr;        }        Cweak& operator =(const smart_ptr<T> &src)        {                //mptr=&*src;                mptr=src.mptr;                return   *this;        }        smart_ptr<T>  lock()        {                return smart_ptr<T>(Cweak<T>(mptr));            }private:        T *mptr;};class A{        public:                A(){cout<<"A"<<endl;}                ~A(){cout<<"~A"<<endl;}                void func()                {                    cout<<"hellowold"<<endl;                }};int main(){        smart_ptr<A> ptr1(new A());    //  smart_ptr<char>ptr2((char*)p);        Cweak<A>ptr3(ptr1);        smart_ptr<A> ptr=ptr3.lock();        if(ptr!=NULL)        {         cout<<"fdsafdsfsdfsdfsdf"<<endl;        }        return 0;}
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