зеркало из https://github.com/mozilla/gecko-dev.git
Bug 1221574 - [08] Add new file cubeb_array_queue.h. r=bustage-fix on a CLOSED TREE
MozReview-Commit-ID: F4aI4R8Zelg
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/*
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* Copyright © 2016 Mozilla Foundation
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*
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* This program is made available under an ISC-style license. See the
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* accompanying file LICENSE for details.
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*/
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#ifndef CUBEB_ARRAY_QUEUE_H
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#define CUBEB_ARRAY_QUEUE_H
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#include <assert.h>
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#include <pthread.h>
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#include <unistd.h>
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#if defined(__cplusplus)
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extern "C" {
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#endif
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typedef struct
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{
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void ** buf;
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size_t num;
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size_t writePos;
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size_t readPos;
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pthread_mutex_t mutex;
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} array_queue;
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array_queue * array_queue_create(size_t num)
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{
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assert(num != 0);
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array_queue * new_queue = (array_queue*)calloc(1, sizeof(array_queue));
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new_queue->buf = (void **)calloc(1, sizeof(void *) * num);
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new_queue->readPos = 0;
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new_queue->writePos = 0;
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new_queue->num = num;
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pthread_mutex_init(&new_queue->mutex, NULL);
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return new_queue;
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}
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void array_queue_destroy(array_queue * aq)
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{
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assert(aq);
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free(aq->buf);
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pthread_mutex_destroy(&aq->mutex);
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free(aq);
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}
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int array_queue_push(array_queue * aq, void * item)
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{
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assert(item);
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pthread_mutex_lock(&aq->mutex);
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int ret = -1;
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if(aq->buf[aq->writePos % aq->num] == NULL)
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{
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aq->buf[aq->writePos % aq->num] = item;
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aq->writePos = (aq->writePos + 1) % aq->num;
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ret = 0;
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}
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// else queue is full
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pthread_mutex_unlock(&aq->mutex);
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return ret;
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}
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void* array_queue_pop(array_queue * aq)
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{
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pthread_mutex_lock(&aq->mutex);
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void * value = aq->buf[aq->readPos % aq->num];
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if(value)
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{
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aq->buf[aq->readPos % aq->num] = NULL;
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aq->readPos = (aq->readPos + 1) % aq->num;
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}
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pthread_mutex_unlock(&aq->mutex);
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return value;
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}
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size_t array_queue_get_size(array_queue * aq)
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{
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pthread_mutex_lock(&aq->mutex);
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ssize_t r = aq->writePos - aq->readPos;
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if (r < 0) {
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r = aq->num + r;
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assert(r >= 0);
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}
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pthread_mutex_unlock(&aq->mutex);
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return (size_t)r;
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}
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#if defined(__cplusplus)
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}
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#endif
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#endif //CUBE_ARRAY_QUEUE_H
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