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/* $Id$ */

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/** @file countedptr.hpp CCountedPtr - smart pointer implementation. */

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#ifndef COUNTEDPTR_HPP

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#define COUNTEDPTR_HPP

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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) {Tcls* pT = m_pT; m_pT = NULL; pT->Release();}}

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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*() {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 = (const 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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/**

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 * Adapter wrapper for CCountedPtr like classes that can't be used directly by stl

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 * collections as item type. For example CCountedPtr has overloaded operator & which

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 * prevents using CCountedPtr in stl collections (i.e. std::list<CCountedPtr<MyType> >)

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 */

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template <class T> struct AdaptT {

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	T m_t;

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	/** construct by wrapping the given object */

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	AdaptT(const T &t)

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		: m_t(t)

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	{}

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	/** assignment operator */

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	T& operator = (const T &t)

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	{

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		m_t = t;

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		return t;

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	}

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	/** type-cast operator (used when AdaptT is used instead of T) */

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	operator T& ()

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	{

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		return m_t;

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	}

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	/** const type-cast operator (used when AdaptT is used instead of const T) */

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	operator const T& () const

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	{

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		return m_t;

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	}

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};

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/** Simple counted object. Use it as base of your struct/class if you want to use

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 *  basic reference counting. Your struct/class will destroy and free itself when

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 *  last reference to it is released (using Relese() method). The initial reference

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 *  count (when it is created) is zero (don't forget AddRef() at least one time if

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 *  not using CCountedPtr<T>.

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 *

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 *  @see misc/countedobj.cpp for implementation.

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 */

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struct SimpleCountedObject {

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	int32 m_ref_cnt;

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	SimpleCountedObject()

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		: m_ref_cnt(0)

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	{}

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	virtual ~SimpleCountedObject()

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	{};

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	virtual int32 AddRef();

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	virtual int32 Release();

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	virtual void FinalRelease() {};

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};

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#endif /* COUNTEDPTR_HPP */