queue.c

#include <stdlib.h>
#include <stdio.h>
#include "queue.h"

void queue_init(queue_t *queue) {
    queue->size = 0;
    queue->elements = NULL;
}

void queue_add(queue_t *queue, void *element) {
    void **temp;
    queue->size++;
    temp = realloc((void *) (queue->elements), sizeof(void *) * (size_t)queue->size);
    if (temp == NULL) {
        fprintf(stderr, "Out of memory\n");
        exit(EXIT_FAILURE);
    }
    queue->elements = temp;
    queue->elements[queue->size - 1] = element;
}

void *queue_extract(queue_t *queue) {
    int i;
    void *element;

    if (queue->elements == NULL)
        return NULL;

    element = queue->elements[0];
    if (queue->size == 0)
        return NULL;
    for (i = 0; i < queue->size - 1; i++) {
        queue->elements[i] = queue->elements[i + 1];
    }
    queue->size--;
    return element;
}

int queue_size(queue_t *queue) {
    return queue->size;
}

void queue_release(queue_t *queue) {
    if (queue->elements)
        free(queue->elements);
}