// TmplBlockBuffer.hpp
//

#pragma once

//-----------------------------------------------------------------------------
//		TmplBlockBuffer
//
//	定义一个连续的内存块
//-----------------------------------------------------------------------------

template <typename T> class TmplBlockBuffer
{
	typedef T __BASE;

private:
	struct MetaData
	{
		long	nRefs;				// reference count
		int		nCount;				// Number of item
	};

protected:
	T			* m_pObject;
	MetaData    * m_pMetaData;

public:
	TmplBlockBuffer ();
	explicit TmplBlockBuffer (T * object, int count);
	TmplBlockBuffer (const TmplBlockBuffer & h);
	TmplBlockBuffer (TmplBlockBuffer && h);

//	从 h 构造一个新的对象, 但是我只要前面的 count 个字符, 如果 count 比 h.nCount 大, 那就重新分配然后 memcpy
	TmplBlockBuffer (TmplBlockBuffer && h, int count);

	virtual ~TmplBlockBuffer ();

public:
	void Attach (T * object, int count);
	T * Detach ();

	// real copy from another TmplBlockBuffer
	void CopyFrom (const TmplBlockBuffer & h);
	// ref-counted copy from another TmplBlockBuffer
	void ShadowCopyFrom (const TmplBlockBuffer & h);

	TmplBlockBuffer & operator = (const TmplBlockBuffer & h);
	TmplBlockBuffer & operator = (TmplBlockBuffer && h);

	T * GetBufferSetCount (int count);
	void CopyFrom (const T * from, int count);
	void CopyTo (T * to, int count) const;

	operator bool () const;
	operator T * ();
	operator const T * () const;

	int  GetCount () const
	{
		if (m_pMetaData)
			return m_pMetaData->nCount;
		return 0;
	}

	// Allow usage as a pointer	
	T * operator -> () 
	{
		return m_pObject;
	}

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

	inline bool operator == (const TmplBlockBuffer & holder) const
	{
		return m_pObject == holder.m_pObject;
	}

	inline bool operator != (const TmplBlockBuffer & holder) const
	{
		return m_pObject != holder.m_pObject;
	}

	T * As ()
	{
		return m_pObject;
	}

	const T * As () const
	{
		return m_pObject;
	}

	template <typename C> C * AS ()
	{
		return (C *) m_pObject;
	}

	template <typename C> const C * AS () const
	{
		return (const C *) m_pObject;
	}

	bool IsEmpty () const;

	void Release ();

protected:
	inline MetaData * GetData () const
	{
		return m_pMetaData;
	}

protected:
	void Init ();

	void MoveAssign (TmplBlockBuffer & Src);
};


//	为像素数据定义一个专用的类型
typedef TmplBlockBuffer <UINT8>  BlockBuffer;

typedef BlockBuffer IBlockBuffer;
typedef BlockBuffer OBlockBuffer;