freebsd-dev/lib/libc_r/uthread/uthread_queue.c

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/*
* Copyright (c) 1995 John Birrell <jb@cimlogic.com.au>.
* 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 John Birrell.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``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 THE REGENTS OR CONTRIBUTORS 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.
*
*/
#include <stdio.h>
#ifdef _THREAD_SAFE
#include <pthread.h>
#include "pthread_private.h"
void
_thread_queue_init(struct pthread_queue * queue)
{
/* Initialise the pointers in the queue structure: */
queue->q_next = NULL;
queue->q_last = NULL;
queue->q_data = NULL;
return;
}
void
_thread_queue_enq(struct pthread_queue * queue, struct pthread * thread)
{
if (queue->q_last) {
queue->q_last->qnxt = thread;
} else {
queue->q_next = thread;
}
queue->q_last = thread;
thread->queue = queue;
thread->qnxt = NULL;
return;
}
struct pthread *
_thread_queue_get(struct pthread_queue * queue)
{
/* Return the pointer to the next thread in the queue: */
return (queue->q_next);
}
struct pthread *
_thread_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->qnxt)) {
queue->q_last = NULL;
}
thread->queue = NULL;
thread->qnxt = NULL;
}
return (thread);
}
int
_thread_queue_remove(struct pthread_queue * queue, struct pthread * thread)
{
struct pthread **current = &(queue->q_next);
struct pthread *prev = NULL;
int ret = -1;
while (*current) {
if (*current == thread) {
if ((*current)->qnxt) {
*current = (*current)->qnxt;
} else {
queue->q_last = prev;
*current = NULL;
}
ret = 0;
break;
}
prev = *current;
current = &((*current)->qnxt);
}
thread->queue = NULL;
thread->qnxt = NULL;
return (ret);
}
int
pthread_llist_remove(struct pthread ** llist, struct pthread * thread)
{
while (*llist) {
if (*llist == thread) {
*llist = thread->qnxt;
return (0);
}
llist = &(*llist)->qnxt;
}
return (-1);
}
#endif