156 lines
4.4 KiB
C
156 lines
4.4 KiB
C
/*
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* Copyright (c) 1998 Daniel Eischen <eischen@vigrid.com>.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Daniel Eischen.
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* 4. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY DANIEL EISCHEN AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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*/
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#include <stdlib.h>
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#include <sys/queue.h>
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#include <string.h>
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#ifdef _THREAD_SAFE
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#include <pthread.h>
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#include "pthread_private.h"
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/* Prototypes: */
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static void pq_insert_prio_list(pq_queue_t *pq, int prio);
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int
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_pq_init(pq_queue_t *pq, int minprio, int maxprio)
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{
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int i, ret = 0;
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int prioslots = maxprio - minprio + 1;
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if (pq == NULL)
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ret = -1;
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/* Create the priority queue with (maxprio - minprio + 1) slots: */
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else if ((pq->pq_lists =
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(pq_list_t *) malloc(sizeof(pq_list_t) * prioslots)) == NULL)
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ret = -1;
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else {
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/* Initialize the queue for each priority slot: */
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for (i = 0; i < prioslots; i++) {
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TAILQ_INIT(&pq->pq_lists[i].pl_head);
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pq->pq_lists[i].pl_prio = i;
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pq->pq_lists[i].pl_queued = 0;
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}
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/* Initialize the priority queue: */
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TAILQ_INIT(&pq->pq_queue);
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/* Remember the queue size: */
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pq->pq_size = prioslots;
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}
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return (ret);
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}
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void
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_pq_remove(pq_queue_t *pq, pthread_t pthread)
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{
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int prio = pthread->active_priority;
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TAILQ_REMOVE(&pq->pq_lists[prio].pl_head, pthread, pqe);
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}
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void
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_pq_insert_head(pq_queue_t *pq, pthread_t pthread)
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{
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int prio = pthread->active_priority;
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TAILQ_INSERT_HEAD(&pq->pq_lists[prio].pl_head, pthread, pqe);
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if (pq->pq_lists[prio].pl_queued == 0)
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/* Insert the list into the priority queue: */
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pq_insert_prio_list(pq, prio);
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}
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void
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_pq_insert_tail(pq_queue_t *pq, pthread_t pthread)
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{
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int prio = pthread->active_priority;
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TAILQ_INSERT_TAIL(&pq->pq_lists[prio].pl_head, pthread, pqe);
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if (pq->pq_lists[prio].pl_queued == 0)
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/* Insert the list into the priority queue: */
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pq_insert_prio_list(pq, prio);
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}
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pthread_t
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_pq_first(pq_queue_t *pq)
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{
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pq_list_t *pql;
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pthread_t pthread = NULL;
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while (((pql = TAILQ_FIRST(&pq->pq_queue)) != NULL) &&
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(pthread == NULL)) {
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if ((pthread = TAILQ_FIRST(&pql->pl_head)) == NULL) {
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/*
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* The priority list is empty; remove the list
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* from the queue.
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*/
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TAILQ_REMOVE(&pq->pq_queue, pql, pl_link);
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/* Mark the list as not being in the queue: */
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pql->pl_queued = 0;
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}
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}
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return (pthread);
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}
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static void
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pq_insert_prio_list(pq_queue_t *pq, int prio)
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{
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pq_list_t *pql;
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/*
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* The priority queue is in descending priority order. Start at
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* the beginning of the queue and find the list before which the
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* new list should to be inserted.
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*/
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pql = TAILQ_FIRST(&pq->pq_queue);
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while ((pql != NULL) && (pql->pl_prio > prio))
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pql = TAILQ_NEXT(pql, pl_link);
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/* Insert the list: */
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if (pql == NULL)
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TAILQ_INSERT_TAIL(&pq->pq_queue, &pq->pq_lists[prio], pl_link);
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else
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TAILQ_INSERT_BEFORE(pql, &pq->pq_lists[prio], pl_link);
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/* Mark this list as being in the queue: */
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pq->pq_lists[prio].pl_queued = 1;
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}
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#endif
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