100 lines
3.3 KiB
C++
100 lines
3.3 KiB
C++
/* $Id$ */
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#ifndef COUNTEDPTR_HPP
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#define COUNTEDPTR_HPP
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/** @file CCountedPtr - smart pointer implementation */
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/** CCountedPtr - simple reference counting smart pointer.
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*
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* One of the standard ways how to maintain object's lifetime.
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*
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* See http://ootips.org/yonat/4dev/smart-pointers.html for more
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* general info about smart pointers.
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*
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* This class implements ref-counted pointer for objects/interfaces that
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* support AddRef() and Release() methods.
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*/
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template <class Tcls_>
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class CCountedPtr {
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/** redefine the template argument to make it visible for derived classes */
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public:
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typedef Tcls_ Tcls;
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protected:
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/** here we hold our pointer to the target */
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Tcls* m_pT;
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public:
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/** default (NULL) construct or construct from a raw pointer */
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FORCEINLINE CCountedPtr(Tcls* pObj = NULL) : m_pT(pObj) {AddRef();};
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/** copy constructor (invoked also when initializing from another smart ptr) */
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FORCEINLINE CCountedPtr(const CCountedPtr& src) : m_pT(src.m_pT) {AddRef();};
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/** destructor releasing the reference */
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FORCEINLINE ~CCountedPtr() {Release();};
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protected:
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/** add one ref to the underlaying object */
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FORCEINLINE void AddRef() {if (m_pT != NULL) m_pT->AddRef();}
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public:
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/** release smart pointer (and decrement ref count) if not null */
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FORCEINLINE void Release() {if (m_pT != NULL) {m_pT->Release(); m_pT = NULL;}}
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/** dereference of smart pointer - const way */
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FORCEINLINE const Tcls* operator -> () const {assert(m_pT != NULL); return m_pT;};
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/** dereference of smart pointer - non const way */
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FORCEINLINE Tcls* operator -> () {assert(m_pT != NULL); return m_pT;};
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/** raw pointer casting operator - const way */
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FORCEINLINE operator const Tcls*() const {assert(m_pT == NULL); return m_pT;}
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/** raw pointer casting operator - non-const way */
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FORCEINLINE operator Tcls*() {assert(m_pT == NULL); return m_pT;}
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/** operator & to support output arguments */
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FORCEINLINE Tcls** operator &() {assert(m_pT == NULL); return &m_pT;}
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/** assignment operator from raw ptr */
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FORCEINLINE CCountedPtr& operator = (Tcls* pT) {Assign(pT); return *this;}
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/** assignment operator from another smart ptr */
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FORCEINLINE CCountedPtr& operator = (CCountedPtr& src) {Assign(src.m_pT); return *this;}
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/** assignment operator helper */
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FORCEINLINE void Assign(Tcls* pT);
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/** one way how to test for NULL value */
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FORCEINLINE bool IsNull() const {return m_pT == NULL;}
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/** another way how to test for NULL value */
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FORCEINLINE bool operator == (const CCountedPtr& sp) const {return m_pT == sp.m_pT;}
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/** yet another way how to test for NULL value */
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FORCEINLINE bool operator != (const CCountedPtr& sp) const {return m_pT != sp.m_pT;}
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/** assign pointer w/o incrementing ref count */
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FORCEINLINE void Attach(Tcls* pT) {Release(); m_pT = pT;}
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/** detach pointer w/o decrementing ref count */
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FORCEINLINE Tcls* Detach() {Tcls* pT = m_pT; m_pT = NULL; return pT;}
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};
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template <class Tcls_>
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FORCEINLINE void CCountedPtr<Tcls_>::Assign(Tcls* pT)
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{
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// if they are the same, we do nothing
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if (pT != m_pT) {
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if (pT) pT->AddRef(); // AddRef new pointer if any
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Tcls* pTold = m_pT; // save original ptr
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m_pT = pT; // update m_pT to new value
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if (pTold) pTold->Release(); // release old ptr if any
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}
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}
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#endif /* COUNTEDPTR_HPP */
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