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/* $Id$ */

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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 */