KUDr@3900: /* $Id$ */
KUDr@3900: 
KUDr@3900: #ifndef  AUTOCOPYPTR_HPP
KUDr@3900: #define  AUTOCOPYPTR_HPP
KUDr@3900: 
KUDr@3900: /** CAutoCopyPtrT - kind of CoW (Copy on Write) pointer.
rubidium@4549:  *  It is non-invasive smart pointer (reference counter is held outside
rubidium@4549:  *  of Tdata).
rubidium@4549:  *  When copied, its new copy shares the same underlaying structure Tdata.
rubidium@4549:  *  When dereferenced, its behavior depends on 2 factors:
rubidium@4549:  *     - whether the data is shared (used by more than one pointer)
rubidium@4549:  *     - type of access (read/write)
rubidium@4549:  *    When shared pointer is dereferenced for write, new clone of Tdata
rubidium@4549:  *  is made first.
rubidium@4549:  *  Can't be used for polymorphic data types (interfaces).
rubidium@4549:  */
KUDr@3900: template <class Tdata_>
KUDr@3900: class CAutoCopyPtrT {
KUDr@3900: protected:
KUDr@3900: 	typedef Tdata_ Tdata;
KUDr@3900: 
rubidium@4434: 	struct CItem {
KUDr@3900: 		int     m_ref_cnt;  ///< reference counter
KUDr@3900: 		Tdata   m_data;     ///< custom data itself
KUDr@3900: 
KUDr@3900: 		FORCEINLINE CItem()                  : m_ref_cnt(1)                     {};
KUDr@3900: 		FORCEINLINE CItem(const Tdata& data) : m_ref_cnt(1), m_data(data)       {};
KUDr@3900: 		FORCEINLINE CItem(const CItem& src)  : m_ref_cnt(1), m_data(src.m_data) {};
KUDr@3900: 	};
KUDr@3900: 
KUDr@3900: 	mutable CItem* m_pI; ///< points to the ref-counted data
KUDr@3900: 
KUDr@3900: public:
KUDr@3900: 	FORCEINLINE CAutoCopyPtrT() : m_pI(NULL) {};
KUDr@3900: 	FORCEINLINE CAutoCopyPtrT(const Tdata& data) : m_pI(new CItem(data)) {};
KUDr@3900: 	FORCEINLINE CAutoCopyPtrT(const CAutoCopyPtrT& src) : m_pI(src.m_pI) {if (m_pI != NULL) m_pI->m_ref_cnt++;}
KUDr@3900: 	FORCEINLINE ~CAutoCopyPtrT() {if (m_pI == NULL || (--m_pI->m_ref_cnt) > 0) return; delete m_pI; m_pI = NULL;}
KUDr@3900: 
KUDr@3900: 	/** data accessor (read only) */
KUDr@3900: 	FORCEINLINE const Tdata& GetDataRO() const {if (m_pI == NULL) m_pI = new CItem(); return m_pI->m_data;}
KUDr@3900: 	/** data accessor (read / write) */
KUDr@3900: 	FORCEINLINE Tdata& GetDataRW() {CloneIfShared(); if (m_pI == NULL) m_pI = new CItem(); return m_pI->m_data;}
KUDr@3900: 
KUDr@3900: 	/** clone data if it is shared */
KUDr@3900: 	FORCEINLINE void CloneIfShared()
KUDr@3900: 	{
KUDr@3900: 		if (m_pI != NULL && m_pI->m_ref_cnt > 1) {
KUDr@3900: 			// we share data item with somebody, clone it to become an exclusive owner
KUDr@3900: 			CItem* pNewI = new CItem(*m_pI);
KUDr@3900: 			m_pI->m_ref_cnt--;
KUDr@3900: 			m_pI = pNewI;
KUDr@3900: 		}
KUDr@3900: 	}
KUDr@3900: 
KUDr@3900: 	/** assign pointer from the other one (maintaining ref counts) */
KUDr@3900: 	FORCEINLINE void Assign(const CAutoCopyPtrT& src)
KUDr@3900: 	{
KUDr@3900: 		if (m_pI == src.m_pI) return;
KUDr@3900: 		if (m_pI != NULL && (--m_pI->m_ref_cnt) <= 0) delete m_pI;
KUDr@3900: 		m_pI = src.m_pI;
KUDr@3900: 		if (m_pI != NULL) m_pI->m_ref_cnt++;
KUDr@3900: 	}
KUDr@3900: 
KUDr@3900: 	/** dereference operator (read only) */
KUDr@3900: 	FORCEINLINE const Tdata* operator -> () const {return &GetDataRO();}
KUDr@3900: 	/** dereference operator (read / write) */
KUDr@3900: 	FORCEINLINE Tdata* operator -> () {return &GetDataRW();}
KUDr@3900: 
KUDr@3900: 	/** assignment operator */
KUDr@3900: 	FORCEINLINE CAutoCopyPtrT& operator = (const CAutoCopyPtrT& src) {Assign(src); return *this;}
KUDr@3900: 
KUDr@3900: 	/** forwarding 'lower then' operator to the underlaying items */
KUDr@3900: 	FORCEINLINE bool operator < (const CAutoCopyPtrT& other) const
KUDr@3900: 	{
KUDr@3900: 		assert(m_pI != NULL);
KUDr@3900: 		assert(other.m_pI != NULL);
KUDr@3900: 		return (m_pI->m_data) < (other.m_pI->m_data);
KUDr@3900: 	}
KUDr@3900: };
KUDr@3900: 
KUDr@3900: 
KUDr@3900: #endif /* AUTOCOPYPTR_HPP */