haiku/headers/private/media/SharedBufferList.h

/*
 * Copyright 2009, Axel Dörfler, axeld@pinc-software.de.
 * Copyright 2002, Marcus Overhagen. All Rights Reserved.
 * Distributed under the terms of the MIT License.
 */
#ifndef _SHARED_BUFFER_LIST_H_
#define _SHARED_BUFFER_LIST_H_


#include <Buffer.h>


namespace BPrivate {


class SharedBufferList {
public:
	static	area_id				Create(SharedBufferList** _list);
	static	SharedBufferList*	Get();
	static	void				Invalidate();

			void				Put();
			void 				DeleteGroupAndPut(sem_id groupReclaimSem);

			status_t			Lock();
			status_t			Unlock();

			status_t			AddBuffer(sem_id groupReclaimSem,
									BBuffer* buffer);
			status_t			RequestBuffer(sem_id groupReclaimSem,
									int32 buffersInGroup, size_t size,
									media_buffer_id wantID, BBuffer** _buffer,
									bigtime_t timeout);
			status_t			RecycleBuffer(BBuffer* buffer);
			status_t			GetBufferList(sem_id groupReclaimSem,
									int32 bufferCount, BBuffer** buffers);

private:
	struct _shared_buffer_info {
		media_buffer_id			id;
		BBuffer*				buffer;
		bool 					reclaimed;
		// The reclaim_sem belonging to the BBufferGroup of this BBuffer
		// is also used as a unique identifier of the group
		sem_id					reclaim_sem;
	};

	enum { kMaxBuffers = 2047 };
		// 16 bytes per buffer, 8 pages in total (one entry less for the list)

			status_t			_Init();
			void 				_RequestBufferInOtherGroups(
									sem_id groupReclaimSem, media_buffer_id id);

private:
			sem_id				fSemaphore;
			vint32				fAtom;

			_shared_buffer_info	fInfos[kMaxBuffers];
			int32				fCount;
};


}	// namespace BPrivate


#endif	// _SHARED_BUFFER_LIST_H_