自己写的share

#pragma once namespace 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(); }