140 lines
3.1 KiB
C
140 lines
3.1 KiB
C
/*
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* Copyright (c) 2015 John R. Bradley <jrb@turrettech.com>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include "ff-circular-queue.h"
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static void *queue_fetch_or_alloc(struct ff_circular_queue *cq,
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int index)
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{
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if (cq->slots[index] == NULL)
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cq->slots[index] = av_mallocz(cq->item_size);
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return cq->slots[index];
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}
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static void queue_lock(struct ff_circular_queue *cq)
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{
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pthread_mutex_lock(&cq->mutex);
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}
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static void queue_unlock(struct ff_circular_queue *cq)
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{
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pthread_mutex_unlock(&cq->mutex);
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}
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static void queue_signal(struct ff_circular_queue *cq)
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{
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pthread_cond_signal(&cq->cond);
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}
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static void queue_wait(struct ff_circular_queue *cq)
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{
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pthread_cond_wait(&cq->cond, &cq->mutex);
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}
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bool ff_circular_queue_init(struct ff_circular_queue *cq, int item_size,
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int capacity)
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{
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memset(cq, 0, sizeof(struct ff_circular_queue));
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cq->item_size = item_size;
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cq->capacity = capacity;
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cq->abort = false;
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cq->slots = av_mallocz(capacity * sizeof(void *));
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if (cq->slots == NULL)
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goto fail;
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cq->size = 0;
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cq->write_index = 0;
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cq->read_index = 0;
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if (pthread_mutex_init(&cq->mutex, NULL) != 0)
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goto fail1;
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if (pthread_cond_init(&cq->cond, NULL) != 0)
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goto fail2;
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return true;
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fail2:
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pthread_mutex_destroy(&cq->mutex);
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fail1:
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av_free(cq->slots);
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fail:
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return false;
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}
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void ff_circular_queue_abort(struct ff_circular_queue *cq)
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{
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queue_lock(cq);
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cq->abort = true;
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queue_signal(cq);
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queue_unlock(cq);
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}
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void ff_circular_queue_free(struct ff_circular_queue *cq)
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{
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ff_circular_queue_abort(cq);
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if (cq->slots != NULL)
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av_free(cq->slots);
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pthread_mutex_destroy(&cq->mutex);
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pthread_cond_destroy(&cq->cond);
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}
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void ff_circular_queue_wait_write(struct ff_circular_queue *cq)
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{
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queue_lock(cq);
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while (cq->size >= cq->capacity && !cq->abort)
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queue_wait(cq);
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queue_unlock(cq);
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}
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void *ff_circular_queue_peek_write(struct ff_circular_queue *cq)
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{
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return queue_fetch_or_alloc(cq, cq->write_index);
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}
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void ff_circular_queue_advance_write(struct ff_circular_queue *cq, void *item)
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{
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cq->slots[cq->write_index] = item;
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cq->write_index = (cq->write_index + 1) % cq->capacity;
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queue_lock(cq);
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++cq->size;
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queue_unlock(cq);
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}
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void *ff_circular_queue_peek_read(struct ff_circular_queue *cq)
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{
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return queue_fetch_or_alloc(cq, cq->read_index);
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}
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void ff_circular_queue_advance_read(struct ff_circular_queue *cq)
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{
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cq->read_index = (cq->read_index + 1) % cq->capacity;
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queue_lock(cq);
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--cq->size;
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queue_signal(cq);
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queue_unlock(cq);
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}
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