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

#include "fifo.h"

size_t fifo_size(struct fifo *fifo)
{
    return fifo->size;
}

void fifo_push(struct fifo *fifo, struct token *elt)
{
    struct list *new = malloc(sizeof(struct list));
    if (new == NULL)
    {
        return;
    }
    new->data = elt;

    if (fifo_size(fifo) == 0)
    {
        fifo->head = new;
    }
    new->next = NULL;
    if (fifo_size(fifo) != 0)
    {
        fifo->tail->next = new;
    }
    fifo->tail = new;

    fifo->size++;
}

struct token *fifo_head(struct fifo *fifo)
{
    return fifo->head->data;
}

void fifo_pop(struct fifo *fifo)
{
    if (fifo_size(fifo) == 0)
    {
        return;
    }
    if (fifo_size(fifo) == 1)
    {
        free(fifo->head->data);
        free(fifo->head);
        fifo->head = NULL;
        fifo->tail = NULL;
        fifo->size = 0;
        return;
    }

    struct list *tmp = fifo->head->next;
    free(fifo->head->data);
    free(fifo->head);
    fifo->head = tmp;

    fifo->size--;
}