circlebuffer.h

来自「MudMaster 2000 的C++源码」· C头文件 代码 · 共 109 行

/************************************************************************************
	Copyright (c) 2000 Aaron O'Neil
	All rights reserved.

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		2) Redistributions in binary form must reproduce the above copyright notice, 
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		3) Redistributions in binary form must reproduce the above copyright notice on
				program startup. Additional credits for program modification are acceptable
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		4) You may charge a reasonable copying fee for any distribution of Mud Master. 
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  THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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	(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

**************************************************************************************/

class CCircleBuffer
{
public:
	CCircleBuffer();
	~CCircleBuffer();

	// Returns TRUE if successfully initialized.  This function can
	// be called more than one if you wish to redimension the
	// buffer.  All data in the buffer at the time of the redim will
	// be lost.
	virtual BOOL Init(int nNumElements, int nElementSize);

	// Add the data to the tail of the buffer. 
	virtual void Add(void *pData, int nDataSize);

	// Turns on data padding.
	void PadData(unsigned char ch)	{ m_bPad = TRUE; m_chPad = ch; }
	// Turns off data padding.
	void NoPad()				{ m_bPad = FALSE; }

	// Makes the buffer empty.
	void Empty()				{ m_nHead = m_nTail = 0; }

	BOOL IsEmpty()				{ return(m_nHead == m_nTail); }

	// Returns the data at the head of the buffer then removes
	// it from the buffer.
	virtual void* RemoveHead();

	virtual void* GetAt(int nIndex);

	// Gives you the data at the head of the buffer.  You need to 
	// call this before calling FindNext.  Will return NULL if the
	// buffer is empty.
	virtual void* FindFirst();
	virtual void* FindLast();

	// Will walk the buffer until the last element has been read.
	// Returns NULL when the end of the buffer has been reached.
	// Don't call this function without calling FindFirst for the 
	// first time.  Also don't call this function after data has
	// been added to the buffer without calling FindFirst again.
	virtual void* FindNext();
	virtual void* FindPrev();

	// Returns TRUE if the Find fucntion is at the top of the
	// buffer.  If this is TRUE the next call to FindPrevious 
	// will return NULL.  Also, if at the top, FindNext will
	// not function correctly.
	BOOL FindAtTop();
	BOOL FindAtBottom();

	int GetNumElements()			{ return(m_nNumElements); }
	int GetElementSize()			{ return(m_nElementSize); }

protected:
	void AdvanceTail();
	void AdvanceHead();
	
	int m_nHead;
	int m_nTail;

	// False by default.  When TRUE if the data addeded to the
	// buffer is shorter than m_nElementSize, the data is padded
	// on the right with m_chPad up to m_nElementSize.
	BOOL m_bPad;
	unsigned char m_chPad;

	int m_nFindIndex;

private:
	int m_nNumElements;
	int m_nElementSize;

	char *m_pBuf;
};