src/sptr.h


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#ifndef SPTR_H
#define SPTR_H

#include <stdint.h>
#include <stdio.h>

template<typename T> class SPtr;
template< typename Tb, typename Ta > SPtr<Tb> SPtrCast( SPtr<Ta> src );

template<typename T>
class SPtr
{
	template<typename Tb, typename Ta>
	friend SPtr<Tb> SPtrCast( SPtr<Ta> pt );
public:
	SPtr() :
		pRefCnt( NULL ),
		pData( NULL )
	{
	}

	~SPtr()
	{
		decCount();
	}

	SPtr( const SPtr<T> &src ) :
		pRefCnt( src.pRefCnt ),
		pData( src.pData )
	{
		if( pRefCnt )
			(*pRefCnt) += 1;
	}

	SPtr( T *pSrc ) :
		pRefCnt( NULL ),
		pData( pSrc )
	{
		pRefCnt = new int32_t;
		(*pRefCnt) = 1;
	}

	int32_t count() const
	{
		return *pRefCnt;
	}

	const T *operator->() const
	{
		return pData;
	}

	const T &operator*() const
	{
		return *pData;
	}
	
	T *operator->()
	{
		return pData;
	}

	T &operator*()
	{
		return *pData;
	}

	SPtr<T> operator=( const SPtr<T> &src )
	{
		decCount();
		pRefCnt = src.pRefCnt;
		pData = src.pData;
		(*pRefCnt) += 1;

		return *this;
	}

	const SPtr<T> operator=( const SPtr<T> &src ) const
	{
		decCount();
		pRefCnt = src.pRefCnt;
		pData = src.pData;
		(*pRefCnt) += 1;

		return *this;
	}

	bool operator==( const SPtr<T> &src ) const
	{
		return pData == src.pData;
	}

	operator bool() const
	{
		return pRefCnt != NULL;
	}

	bool isSet() const
	{
		return pRefCnt != NULL;
	}

private:
	void decCount() const
	{
		if( pRefCnt )
		{
			(*pRefCnt) -= 1;
			//printf("Decrementing ref-count to %d\n", *pRefCnt );
			if( (*pRefCnt) == 0 )
			{
				delete pRefCnt;
				delete pData;
				pRefCnt = NULL;
				pData = NULL;
			}
		}
	}

	mutable int32_t *pRefCnt;
	mutable T *pData;
};

template< typename Tb, typename Ta > SPtr<Tb> SPtrCast( SPtr<Ta> src )
{
	SPtr<Tb> ret;
	ret.pRefCnt = src.pRefCnt;
	ret.pData = dynamic_cast<Tb *>(src.pData);
	if( ret.pRefCnt )
		(*(ret.pRefCnt)) += 1;
	return ret;
}

#endif