rtpqueueinternal.c

来自「linux环境下用纯c写的RTP协议的通用开发库」· C语言 代码 · 共 114 行

/*-------------------------------------------------------------------------
 * rtpqueueinternal.c - _rtpqclear, _rtpqinsert, rtpqueueextract
 *-------------------------------------------------------------------------
 */

#include <rtp.h>
#include <pthread.h>
#include <stdlib.h>
#include <strings.h>

/*------------------------------------------------------------------------
 * _rtpqclear - free all packets from a stream's RTP queue.
 * Assumes queue already locked.
 *------------------------------------------------------------------------
 */
int
_rtpqclear(struct rtpqueue *pq)
{
  
	struct rtpln		*p, *q;
  
	p = pq->rq_tail;
	while (p != NULL) {
		q = p->rln_next;
		bufpoolfreebuf(p);
		p = q;
	}
	pq->rq_tail = NULL;
	pq->rq_head = NULL;

	return OK;
}

/*------------------------------------------------------------------------
 * _rtpqinsert - insert a node into a stream's RTP queue.
 * Assumes queue already locked.
 *------------------------------------------------------------------------
 */
int
_rtpqinsert(struct rtpqueue *pq, struct rtpln *pln, bool *head)
{
  
	struct rtpln    *p, *q;
  
	if (head != NULL)
		*head = FALSE;

	p = pq->rq_tail;
	q = NULL;

	while (p != NULL && p->rln_seq > pln->rln_seq) {
		q = p;
		p = p->rln_next;
	}

	if (q != NULL) {
		q->rln_next = pln;
		pln->rln_prev = q;
	}
	else {
		pq->rq_tail = pln;
		pln->rln_prev = NULL;
	}
	if (p != NULL) {
		p->rln_prev = pln;
		pln->rln_next = p;
	}
	else {
		pq->rq_head = pln;
		pln->rln_next = NULL;
		if (head != NULL)
			*head = TRUE;
	}
	pq->rq_len += pln->rln_len;

	return OK;
}

/*------------------------------------------------------------------------
 * rtpqextract - extrace a packet from the doubly-linked list
 * Assumes queue already locked.
 *------------------------------------------------------------------------
 */
struct rtpln *
rtpqextract(struct rtpqueue *pq, struct rtpln *pln)
{
  
	struct rtpln *n, *p;

	if (pln == NULL)
		return NULL;
  

	n = pln->rln_next;
	p = pln->rln_prev;

	if (n != NULL) 
		n->rln_prev = p;
	else 
		pq->rq_head = p;
    
	if (p != NULL)
		p->rln_next = n;
	else
		pq->rq_tail = n;

	pln->rln_next = NULL;
	pln->rln_prev = NULL;

	pq->rq_len -= pln->rln_len;

	return pln;
}