code/mandelbrot/queue.c

#include "mandelbrot.h"

queue_t *initialize_queue()
{
	queue_t *q;

	q = (queue_t *) malloc(sizeof(queue_t *));

	return q;
}

void enqueue(queue_t * q, mandel_t * w, pthread_mutex_t * lock)
{
	struct queue_node_t *aux;

	pthread_mutex_lock(lock);

	if (q->head == NULL) {
		q->head =
		    (struct queue_node_t *)
		    malloc(sizeof(struct queue_node_t *));
		q->head->next = NULL;
		q->head->node = w;
		q->tail = q->head;
	} else {
		aux =
		    (struct queue_node_t *)
		    malloc(sizeof(struct queue_node_t *));
		aux->next = NULL;
		aux->node = w;
		q->tail->next = aux;
		q->tail = aux;
	}

	pthread_mutex_unlock(lock);
}

mandel_t *dequeue(queue_t * q, pthread_mutex_t * lock)
{
	struct queue_node_t *aux;
	mandel_t *ret_val;
	pthread_mutex_lock(lock);
	
	if (q->head == NULL) {
		ret_val = NULL;
	}
	else if (q->head == q->tail) {
		aux = q->head;
		ret_val = aux->node;
		q->head = NULL;
		q->tail = NULL;
	}
	else {
		aux = q->head;
		ret_val = aux->node;
		q->head = aux->next;
	}
	pthread_mutex_unlock(lock);
	return ret_val;

}

int is_empty(queue_t * q, pthread_mutex_t * lock)
{
	int ret = 0;
	pthread_mutex_lock(lock);
	if (q->head == NULL) ret = 1;
	pthread_mutex_unlock(lock);
	
	return (ret);
}

void destroy_queue(queue_t * q)
{
	struct queue_node_t *aux, *next;

	aux = q->head;

	while (aux != NULL) {
		next = aux->next;
		free(aux);
		if (next != NULL)
			aux = next;
	}
	free(q);
}