haiku/headers/private/media/SharedBufferList.h

/***********************************************************************
 * Copyright (c) 2002 Marcus Overhagen. All Rights Reserved.
 * This file may be used under the terms of the OpenBeOS License.
 *
 * Used for BBufferGroup and BBuffer management across teams
 ***********************************************************************/
#ifndef _SHARED_BUFFER_LIST_H_
#define _SHARED_BUFFER_LIST_H_

#include <Buffer.h>

// created in the media server, cloned into 
// each BBufferGroup (visible in all address spaces / teams)
struct _shared_buffer_list
{
	struct _shared_buffer_info
	{
		media_buffer_id id;
		BBuffer *		buffer;
		bool 			reclaimed;
		// the reclaim_sem belonging to the BBufferGroup of this BBuffer
		// also used as a unique identifier of the group
		sem_id			reclaim_sem; 
	};
	enum { MAX_BUFFER = 666 };			// this fixed limit is probably very evil

	sem_id		locker_sem;
	int32		locker_atom;
	
	// always only the first "buffercount" entries in the "info" array are used
	int32		buffercount;
	_shared_buffer_info info[MAX_BUFFER];

	status_t	AddBuffer(sem_id group_reclaim_sem, BBuffer *buffer);
	status_t	RequestBuffer(sem_id group_reclaim_sem, int32 buffers_in_group, size_t size, media_buffer_id wantID, BBuffer **buffer, bigtime_t timeout);
	status_t	GetBufferList(sem_id group_reclaim_sem, int32 buf_count, BBuffer **out_buffers);
	status_t	RecycleBuffer(BBuffer *buffer);
	
		
	status_t 	Init();

	static _shared_buffer_list *Clone(area_id id = -1);
	void 		Terminate(sem_id group_reclaim_sem);
	void 		Unmap();

	status_t	Lock();
	status_t	Unlock();
	
	// used by RequestBuffer, call this one with the list locked!
	void 		RequestBufferInOtherGroups(sem_id group_reclaim_sem, media_buffer_id id);
};

#endif