Implementation of the Queue.

queue.c

#include <stdlib.h>
#include "queue.h"
#include "../LinkedList/linked_list.h"

struct Queue {
  pLinkedList buffer;
};

pQueue makeQueue() {
  pQueue newQueue = malloc(sizeof(Queue));

  newQueue->buffer = makeList();

  return newQueue;
}

size_t push(pQueue queue, T data) {
  if (queue == NULL) return 0; // FAILED, returns 0.

  appendToList(queue->buffer, data);

  return queue->buffer->size;
}

T* pop(pQueue queue) {
  if (queue == NULL) return NULL; // No Queue

  pNode front = removeFront(queue->buffer);

  if (front == NULL) return NULL; // Nothing in the queue

  return front->data;
}

size_t queueSize(pQueue queue) {
  return queue->buffer->size;
}

void destroyQueue(pQueue* pPqueue) {
  if (pPqueue == NULL) return; // Nothing here.

  pQueue queue = *pPqueue;

  destroyList(&queue->buffer);
  queue->buffer = NULL;

  free(queue);
  *pPqueue = NULL;
  pPqueue = NULL;
  queue = NULL;
}