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/*
* Queue handling
* Copyright (C) 2006 Unix Solutions Ltd.
*
* Released under MIT license.
* See LICENSE-MIT.txt for license terms.
*/
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <errno.h>
#include <err.h>
#include <pthread.h>
#include "libfuncs.h"
#include "queue.h"
QUEUE *queue_new(void) {
pthread_mutex_t *mutex = malloc(sizeof(pthread_mutex_t));
if (pthread_mutex_init(mutex,NULL) != 0) {
perror("queue_new: mutex_init");
return NULL;
}
pthread_cond_t *cond = malloc(sizeof(pthread_cond_t));
if (pthread_cond_init(cond,NULL)!=0){
perror("queue_new: cond_init");
return NULL;
}
QUEUE *q = calloc(1, sizeof(QUEUE));
if (!q)
return NULL;
// initialize queue
q->mutex = mutex;
q->cond = cond;
return q;
}
void queue_free(QUEUE **pq) {
QUEUE *q = *pq;
if (!q)
return;
while (q->items > 0) {
queue_get(q);
}
pthread_mutex_destroy(q->mutex);
FREE(q->mutex);
pthread_cond_destroy(q->cond);
FREE(q->cond);
FREE(*pq);
}
void queue_add(QUEUE *q, void *data) {
if (!q)
return;
QNODE *a_msg = malloc(sizeof(QNODE));
if (!a_msg) {
perror("queue_enqueue, malloc:");
return;
}
a_msg->data = data;
a_msg->next = NULL;
pthread_mutex_lock(q->mutex);
if (q->items == 0) { // special case - queue is empty
q->head = a_msg;
q->tail = a_msg;
} else {
q->tail->next = a_msg;
q->tail = a_msg;
}
q->items++;
pthread_cond_signal(q->cond);
pthread_mutex_unlock(q->mutex);
}
void *queue_get(QUEUE *q) {
if (!q)
return NULL;
pthread_mutex_lock(q->mutex);
while (q->items==0) {
pthread_cond_wait(q->cond, q->mutex);
if (q->items == 0)
return NULL;
}
if (!q || !q->head || q->items == 0) // Can happen in free
return NULL;
QNODE *a_msg = q->head;
q->head = a_msg->next;
if (q->head == NULL) { // this was last msg
q->tail = NULL;
}
q->items--;
pthread_cond_signal(q->cond);
pthread_mutex_unlock(q->mutex);
void *data = a_msg->data;
FREE(a_msg);
return data;
}
void *queue_get_nowait(QUEUE* q) {
if (!q || q->items == 0)
return NULL;
return queue_get(q);
}
void queue_wakeup(QUEUE *q) {
if (q) {
pthread_cond_signal(q->cond);
}
}
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