omsbuff_addpage.c

linux下的rtp的实例源代码

/* * 
 *  $Id: OMSbuff_addpage.c 327 2006-03-28 16:14:41Z 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 <fenice/bufferpool.h>
#include <fenice/fnc_log.h>

/*\brief internal function used to add a page of slots (of OMSBUFF_MEM_PAGE size).
 * WARNING: the function assumes that the caller (OMSbuff_write or OMSbuff_getslot) locked the buffer mutex
 * \return the first OMSSlot of new added page of slots.
 * */
OMSSlot *OMSbuff_addpage(OMSBuffer *buffer, OMSSlot *prev)
{
	OMSSlot *added;
	unsigned int i;
	ptrdiff_t prev_diff;

	switch (buffer->type) {
		case buff_shm:
			prev_diff = prev - buffer->slots;
			added = OMSbuff_shm_addpage(buffer);
			prev = buffer->slots + prev_diff;
			
			buffer->slots[buffer->known_slots-1].next = prev->next; // last added slot in shm new page is linked to the prev->next in old queue

			fnc_log(FNC_LOG_DEBUG,"OMSSlots page added in SHM memory (%u slots)\n", buffer->known_slots);
			break;
		case buff_local:
			prev_diff = prev - buffer->slots;
			if ( !(added=realloc(buffer->slots, (buffer->control->nslots+OMSBUFF_MEM_PAGE)*sizeof(OMSSlot))) )
				return NULL;
			buffer->slots = added;
			
			prev = buffer->slots + prev_diff;
			// init new slots
			for (i=buffer->control->nslots; i<buffer->control->nslots+OMSBUFF_MEM_PAGE-1; i++) {
				added[i].refs = 0;
				added[i].slot_seq = 0;
				added[i].next = i + 1;
			}
			// last slot
			added[i].refs = 0;
			added[i].slot_seq = 0;
			added[i].next = prev->next;
			
			added = &added[buffer->control->nslots];
			buffer->control->nslots += OMSBUFF_MEM_PAGE;
			buffer->known_slots = buffer->control->nslots;
			
			fnc_log(FNC_LOG_DEBUG,"OMSSlots page added in local bufferpool (%u slots)\n", buffer->known_slots);
			break;
		default:
			return NULL;
			break;
	}

	prev->next = OMStoSlotPtr(buffer, added);

	return added;
}