queue.c
上传用户:tsgydb
上传日期:2007-04-14
资源大小:10674k
文件大小:4k
- /* ==== queue.c ============================================================
- * Copyright (c) 1993, 1994 by Chris Provenzano, proven@mit.edu
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- * 3. All advertising materials mentioning features or use of this software
- * must display the following acknowledgement:
- * This product includes software developed by Chris Provenzano.
- * 4. The name of Chris Provenzano may not be used to endorse or promote
- * products derived from this software without specific prior written
- * permission.
- *
- * THIS SOFTWARE IS PROVIDED BY CHRIS PROVENZANO ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL CHRIS PROVENZANO BE LIABLE FOR ANY
- * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
- * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
- * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
- * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- *
- * Description : Queue functions.
- *
- * 1.00 93/07/15 proven
- * -Started coding this file.
- */
- #ifndef lint
- static const char rcsid[] = "$Id$";
- #endif
- #include <pthread.h>
- /*
- * All routines in this file assume that the queue has been appropriatly
- * locked.
- */
- /* ==========================================================================
- * pthread_queue_init()
- */
- void pthread_queue_init(struct pthread_queue *queue)
- {
- queue->q_next = NULL;
- queue->q_last = NULL;
- queue->q_data = NULL;
- }
- /* ==========================================================================
- * pthread_queue_enq()
- */
- void pthread_queue_enq(struct pthread_queue *queue, struct pthread *thread)
- {
- if (queue->q_last) {
- queue->q_last->next = thread;
- } else {
- queue->q_next = thread;
- }
- queue->q_last = thread;
- thread->queue = queue;
- thread->next = NULL;
-
- }
- /* ==========================================================================
- * pthread_queue_get()
- */
- struct pthread *pthread_queue_get(struct pthread_queue *queue)
- {
- return(queue->q_next);
- }
- /* ==========================================================================
- * pthread_queue_deq()
- */
- struct pthread *pthread_queue_deq(struct pthread_queue *queue)
- {
- struct pthread *thread = NULL;
- if (queue->q_next) {
- thread = queue->q_next;
- if (!(queue->q_next = queue->q_next->next)) {
- queue->q_last = NULL;
- }
- thread->queue = NULL;
- thread->next = NULL;
- }
- return(thread);
- }
- /* ==========================================================================
- * pthread_queue_remove()
- */
- int pthread_queue_remove(struct pthread_queue *queue, struct pthread *thread)
- {
- struct pthread **current = &(queue->q_next);
- struct pthread *prev = NULL;
- int ret = NOTOK;
- while (*current) {
- if (*current == thread) {
- if ((*current)->next) {
- *current = (*current)->next;
- } else {
- queue->q_last = prev;
- *current = NULL;
- }
- thread->queue = NULL;
- thread->next = NULL;
- ret = OK;
- break;
- }
- prev = *current;
- current = &((*current)->next);
- }
- return(ret);
- }
- /* ==========================================================================
- * pthread_llist_remove()
- */
- int pthread_llist_remove(struct pthread **llist, struct pthread *thread)
- {
- while (*llist) {
- if (*llist == thread) {
- *llist = thread->next;
- return(OK);
- }
- llist = &(*llist)->next;
- }
- return(NOTOK);
- }