/*!	\mainpage 具有頭部格式的緩沖區(qū)
 *	\author nodman
 *	\date	2003-6-11
 */

#ifndef _HEADER_BUF_H
#define _HEADER_BUF_H

/// 處理具有頭部格式的緩沖區(qū)
template<typename T>
class header_buf
{
	T* x;		///< buffer with header and followed by data
	DWORD s;	///< data size, excluding the header size
public:
	header_buf():x(NULL),s(0){}
	// size: pure data size, exlcuding the header size
	header_buf(T* t, DWORD size):x(NULL), s(0){attach(t,size);}

	void attach(T* t, DWORD size)
	{
		x = t;
		s = size;
	}

	void detach()
	{
		x = NULL;
		s = 0;
	}

	DWORD data_size() const {return s;}
	DWORD header_size() const {return sizeof(T);}
	DWORD whole_size() const {return s+header_size();}

	operator T*() {return x;}
	byte* data() {return ((byte*)x)+header_size();}
	T* tail() {return ((byte*)x)+whole_size();}

	T* operator->(){return x;}
};

#endif	// _HEADER_BUF_H