63 lines
2.0 KiB
C
63 lines
2.0 KiB
C
/* Linuxthreads - a simple clone()-based implementation of Posix */
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/* threads for Linux. */
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/* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr) */
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/* */
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/* This program is free software; you can redistribute it and/or */
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/* modify it under the terms of the GNU Library General Public License */
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/* as published by the Free Software Foundation; either version 2 */
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/* of the License, or (at your option) any later version. */
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/* */
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/* This program is distributed in the hope that it will be useful, */
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/* but WITHOUT ANY WARRANTY; without even the implied warranty of */
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/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the */
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/* GNU Library General Public License for more details. */
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/* Waiting queues */
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typedef struct _pthread_queue pthread_queue;
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static inline void queue_init(pthread_queue * q)
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{
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q->head = q->tail = NULL;
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}
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static inline void enqueue(pthread_queue * q, pthread_descr th)
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{
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int prio;
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pthread_descr * elt;
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ASSERT(th->p_nextwaiting == NULL);
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if (q->tail == NULL) {
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q->head = th;
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q->tail = th;
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return;
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}
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prio = th->p_priority;
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if (prio > 0) {
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/* Insert in queue according to priority order */
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for (elt = &(q->head); *elt != NULL; elt = &((*elt)->p_nextwaiting)) {
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if (prio > (*elt)->p_priority) {
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th->p_nextwaiting = *elt;
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*elt = th;
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return;
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}
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}
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}
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/* Priority is no greater than any thread in the queue.
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Insert at end of queue */
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q->tail->p_nextwaiting = th;
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q->tail = th;
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}
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static inline pthread_descr dequeue(pthread_queue * q)
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{
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pthread_descr th;
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th = q->head;
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if (th != NULL) {
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q->head = th->p_nextwaiting;
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if (q->head == NULL) q->tail = NULL;
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th->p_nextwaiting = NULL;
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}
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return th;
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}
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