自己写的share_ptr

来源：互联网发布：莫扎特圆号协奏曲软件编辑：程序博客网时间：2024/06/01 09:00

#pragma oncenamespace WSBoost{template<class T> class shared_ptr{private:typedef int count_type;public:explicit shared_ptr(T * p = 0): px(p){pn = new count_type(1);}~shared_ptr(){if(--*pn == 0){delete px;delete pn;}}shared_ptr(shared_ptr const & r): px(r.px), pn(r.pn){++*pn;}shared_ptr & operator=(shared_ptr const & r){if (this != &r){pn = r.pn;px = r.px;++ *pn;}return *this;}private:T * px; count_type * pn;};}

另外一个版本的CSTring 和 share_ptr

#include "MyStudyFile.h"#include <crtdbg.h>#include <boost/smart_ptr/shared_ptr.hpp>int  strlength (const char * str){const char *eos = str;while( *eos++ ) ;return( eos - str - 1 );}char *  strcapend (char * dst,const char * src){char * cp = dst;while( *cp )cp++;while( *cp++ = *src++ ) ;return( dst );}char * __cdecl strcopy(char * dst, const char * src){char * cp = dst;while( *cp++ = *src++ );return( dst );}//共享的实现。template<class T>class ShareDataImp{typedef T ElementType;private:struct SharedData{SharedData(ElementType* p = NULL):m_p(p), nRef(1){}void AddRef(){++ nRef;}void Release(){if (-- nRef == 0){delete[] m_p;m_p = NULL;}}ElementType* GetPtr(){return m_p;}int GetCount(){return nRef;}private:ElementType* m_p;int nRef;};public:ShareDataImp(ElementType* pstr = NULL) : m_pData(new SharedData(pstr)){}~ShareDataImp(){m_pData->Release();if (m_pData->GetCount() == 0){delete m_pData;}m_pData = NULL;}ShareDataImp(const ShareDataImp& _right): m_pData(_right.m_pData){m_pData->AddRef();}//释放对共享数据的所有权。void ResetAs(ElementType* p){m_pData->Release();delete m_pData;m_pData = new SharedData(p);}char* Get() const{return m_pData->GetPtr();}private:SharedData* m_pData;};class CString{public:CString(char* pStr){char* pNewStr = new char[strlength(pStr) + 1];strcopy(pNewStr, pStr);m_shareData.ResetAs(pNewStr);}~CString(){}const char* cstr() const{ return m_shareData.Get();}CString& Append(CString& strVal){CString strRight(strVal.cstr());m_shareData.ResetAs(CloneData(GetLength() + strVal.GetLength() + 1));strcapend(cstr(), strRight.cstr());return *this;}CString& Assign(const CString& strVal){m_shareData.ResetAs(strVal.CloneData(strVal.GetLength() + 1));return *this;}CString& Assign(char* pStr){CString strRight(pStr);m_shareData.ResetAs(strRight.cstr());return *this;}int GetLength() const{return strlength(m_shareData.Get());}private:char* cstr(){return  m_shareData.Get();}char* CloneData(int iSize) const{char* pStr = new char[ iSize];strcopy(pStr, cstr());return pStr;}ShareDataImp<char> m_shareData;};int main(){CString* pVal = new  CString("1");CString* pVa2 = new  CString(*pVal);CString* pVa3 = new  CString(*pVa2);CString* pVa4 = new  CString(*pVa3);delete pVal;delete pVa2;delete pVa3;delete pVa4;_CrtDumpMemoryLeaks();}

阅读全文

0 0