barrier/lib/io/CStreamBuffer.h

#ifndef CSTREAMBUFFER_H
#define CSTREAMBUFFER_H

#include "BasicTypes.h"
#include "stdlist.h"
#include "stdvector.h"

//! FIFO of bytes
/*!
This class maintains a FIFO (first-in, last-out) buffer of bytes.
*/
class CStreamBuffer {
public:
	CStreamBuffer();
	~CStreamBuffer();

	//! @name manipulators
	//@{

	//! Read data without removing from buffer
	/*!
	Return a pointer to memory with the next \c n bytes in the buffer
	(which must be <= getSize()).  The caller must not modify the returned
	memory nor delete it.
	*/
	const void*			peek(UInt32 n);

	//! Discard data
	/*!
	Discards the next \c n bytes.  If \c n >= getSize() then the buffer
	is cleared.
	*/
	void				pop(UInt32 n);

	//! Write data to buffer
	/*!
	Appends \c n bytes from \c data to the buffer.
	*/
	void				write(const void* data, UInt32 n);

	//@}
	//! @name accessors
	//@{

	//! Get size of buffer
	/*!
	Returns the number of bytes in the buffer.
	*/
	UInt32				getSize() const;

	//@}

private:
	static const UInt32	kChunkSize;

	typedef std::vector<UInt8> Chunk;
	typedef std::list<Chunk> ChunkList;

	ChunkList			m_chunks;
	UInt32				m_size;
	UInt32				m_headUsed;
};

#endif