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queue.c
107 lines (89 loc) · 2.36 KB
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queue.c
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/*
* Copyright 2021 Regents of the University of Michigan
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "queue.h"
#include "xalloc.h"
#include <pthread.h>
zqueue_t *queue_init(void)
{
zqueue_t *p = xmalloc(sizeof(zqueue_t));
p->front = NULL;
p->back = NULL;
p->size = 0;
pthread_mutex_init(&p->lock, NULL);
pthread_cond_init(&p->empty, NULL);
return p;
}
int is_empty(zqueue_t *queue) { return queue->size == 0; }
void push_back(void *data, zqueue_t *queue)
{
znode_t *new_node = xmalloc(sizeof(znode_t));
new_node->prev = NULL;
new_node->next = NULL;
new_node->data = data;
pthread_mutex_lock(&queue->lock);
if (is_empty(queue)) {
queue->front = new_node;
queue->back = new_node;
} else {
queue->back->next = new_node;
new_node->prev = queue->back;
queue->back = new_node;
}
queue->size++;
pthread_cond_signal(&queue->empty);
pthread_mutex_unlock(&queue->lock);
}
znode_t *pop_front(zqueue_t *queue)
{
pthread_mutex_lock(&queue->lock);
while (is_empty(queue)) {
pthread_cond_wait(&queue->empty, &queue->lock);
}
znode_t *temp = pop_front_unsafe(queue);
pthread_mutex_unlock(&queue->lock);
return temp;
}
znode_t *pop_front_unsafe(zqueue_t *queue)
{
znode_t *temp = queue->front;
queue->front = temp->next;
if (queue->front != NULL) {
queue->front->prev = NULL;
}
queue->size--;
return temp;
}
znode_t *get_front(zqueue_t *queue)
{
pthread_mutex_lock(&queue->lock);
while (is_empty(queue)) {
pthread_cond_wait(&queue->empty, &queue->lock);
}
znode_t *temp = queue->front;
pthread_mutex_unlock(&queue->lock);
return temp;
}
znode_t *get_back(zqueue_t *queue)
{
pthread_mutex_lock(&queue->lock);
while (is_empty(queue)) {
pthread_cond_wait(&queue->empty, &queue->lock);
}
znode_t *temp = queue->back;
pthread_mutex_unlock(&queue->lock);
return temp;
}
size_t get_size(zqueue_t *queue) { return queue->size; }