omsbuff_write.c

linux下的rtp的实例源代码

/* * 
 *  $Id: OMSbuff_write.c 333 2006-03-31 18:40:05Z shawill $
 *  
 *  This file is part of Fenice
 *
 *  Fenice -- Open Media Server
 *
 *  Copyright (C) 2004 by
 *  	
 *	- Giampaolo Mancini	<[e-mail]>
 *	- Francesco Varano	<[e-mail]>
 *	- Marco Penno		<[e-mail]>
 *	- Federico Ridolfo	<[e-mail]>
 *	- Eugenio Menegatti 	<[e-mail]>
 *	- Stefano Cau
 *	- Giuliano Emma
 *	- Stefano Oldrini
 * 
 *  Fenice is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  Fenice is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with Fenice; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *  
 * */

#include <sys/mman.h>

#include <stdio.h>
#include <string.h>
#include <fenice/utils.h>
#include <fenice/bufferpool.h>

/*! \brief Write a new slot in the buffer using the input parameters.
 *  
 *  The function writes a new slot according with input parameters. If the
 *  <tt>data</tt> belongs to a slot that was prevoiusly requested with
 *  <tt>OMSbuff_getslot</tt> then there is not the copy of data, just the
 *  parameter setting like a commit of changes done.
 * \param seq impose explicitly the sequence number of pkt(slot). If this parameter is 0 the
 * it's set calculating 'prev_seq+1'.
 *  \return ERR_NOERROR or ERR_ALLOC
 *  */
int32 OMSbuff_write(OMSBuffer *buffer, uint64 seq, uint32 timestamp, uint8 marker, uint8 *data, uint32 data_size)
{
	OMSSlot *slot = &buffer->slots[buffer->control->write_pos];
	uint64 curr_seq = slot->slot_seq;
	OMSSlot *valid_read_pos = &buffer->slots[buffer->control->valid_read_pos];
	double ts;
	
	OMSbuff_lock(buffer);
	
	if (OMSbuff_shm_refresh(buffer))
		return ERR_ALLOC;
	
	if (buffer->slots[slot->next].data == data) {
		slot = &buffer->slots[slot->next];
	} else {
		if (buffer->slots[slot->next].refs > 0) {
			if ((slot = OMSbuff_addpage(buffer, slot)) == NULL) {
				OMSbuff_unlock(buffer);
				return ERR_ALLOC;
			}
		} else {
			slot = &buffer->slots[slot->next];
			// write_pos reaches valid_read_pos, we "push" it
			if ( (valid_read_pos->slot_seq) && (valid_read_pos == slot) ) {
				for (ts=valid_read_pos->timestamp;\
						(buffer->slots[valid_read_pos->next].slot_seq) && (ts==valid_read_pos->timestamp);\
						ts=valid_read_pos->timestamp, valid_read_pos=&buffer->slots[valid_read_pos->next]);
				buffer->control->valid_read_pos = OMStoSlotPtr(buffer, valid_read_pos);
			}
		}

		memcpy(slot->data,data,data_size);
	}

	slot->timestamp = timestamp;
	slot->marker = marker;
	slot->data_size=data_size;
	
	slot->refs = buffer->control->refs;
	slot->slot_seq = seq ? seq : curr_seq + 1;
	
	buffer->control->write_pos = OMStoSlotPtr(buffer, slot);
		
//	if ( msync(slot, sizeof(OMSSlot), MS_ASYNC) )
//	if ( msync(buffer->slots, buffer->known_slots*sizeof(OMSSlot), MS_ASYNC) )
//		printf("*** slot msync error\n");
//	if ( msync(buffer->control, sizeof(OMSControl), MS_ASYNC) )
//		printf("*** control msync error\n");
	OMSbuff_dump(NULL, buffer);
	
	OMSbuff_unlock(buffer);

	return ERR_NOERROR;
}