omsbuff_read.c

linuxUNIX下跑的一套服务端程序

/* * 
 *  $Id: OMSbuff_read.c 128 2005-04-29 11:07:58Z 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 <stdio.h>
#include <string.h>

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

/* ! Read the next slot in buffer.
 *
 * Read the next slot in the buffer fill the parameters given as input and move
 * current read position.
 *
 * \param cons is the consumer.
 * \param timestamp return position for timestamp value of slot read.
 * \param marker return position for marker value of slot read.
 * \param data position of where to copy data filed of the read slot.
 * \param data_size input value for size of <tt>data</tt> buffer and return
 * value for size of effective size of read data.
 *
 * \return -1 on error, 1 if slot data size is bigger thar size of buffer
 * provided and then it was not possible to copy all the data, 0 otherwise.
 * 
 * */
// OMSSlot *OMSbuff_read(OMSConsumer *cons)
int32 OMSbuff_read(OMSConsumer *cons, uint32 *timestamp, uint8 *marker, uint8 *data, uint32 *data_size)
{
	OMSSlot *last_read = cons->last_read_pos;
	// OMSSlot *next = cons->read_pos->next;
	OMSSlot *next = cons->read_pos;
	uint32 cpy_size;

	if ( !next->refs || (next->slot_seq < cons->last_seq) ) {
		// added some slots?
		if ( last_read && last_read->next->refs && (last_read->next->slot_seq > cons->last_seq) )
			next = last_read->next;
		else
			return -1; // NULL;
	} else if (last_read && ( last_read->next->slot_seq < next->slot_seq ) )
			next = last_read->next;

	cpy_size = omsbuff_min(*data_size, next->data_size);

	next->refs--;

	cons->last_seq = next->slot_seq;
	// cons->read_pos = next;

	cons->last_read_pos = next;
	cons->read_pos = next->next;

	// cons->read_pos->refs--;
	// fill input parameters
	*timestamp = next->timestamp;
	*marker = next->marker;
	memcpy(data, next->data, cpy_size);
	*data_size = cpy_size;

	
	// return cons->read_pos;
	return (cpy_size == next->data_size) ? 0 : 1; // next;

#if 0 // shawill: old read
	OMSSlot *read_pos = cons->read_pos;

	if ( !read_pos->refs )
		return NULL;

	cons->read_pos->refs--;
	
	cons->read_pos = read_pos->next;

	return read_pos;
#endif
		
}