#include "queue.h"
#include <stdio.h>
#include <stdlib.h>
void queue_create(struct queue* container){
    my_assert(container != NULL);
    container->first = NULL;
    container->last = NULL;
}
void queue_push (struct queue* container, struct instruction* item){
    my_assert(container != NULL);
    if (item == NULL)
        fprintf(stderr, "Chybny argument!\n");
    else if (container->first == container->last){
        container->first = item;
        container->last = item;
    }
    else {
        container->last->next = item;
        container->last = item;
    }
}
struct instruction* queue_pop (struct queue* container){
    my_assert(container != NULL);
    struct instruction *temp = container->first;
    if ((container->first == NULL) && (container->last == NULL)){
        fprintf(stderr, "Fronta je prazdna!\n");
        return NULL;
    }
    else if (container->first == container->last){
        container->first = temp->next;
        container->last = NULL;
    }
    else container->first = temp->next;
    return temp;
}
unsigned int queue_empty (const struct queue* container){
    my_assert(container != NULL);
    if ((container->first == NULL) && (container->last == NULL))
        return 1;
    else return 0;
}
unsigned int queue_size (const struct queue* container){
    my_assert(container != NULL);
    struct instruction *temp = container->first;
    int count = 0;
    while (temp != NULL){
        temp=temp->next;
        count++;
    }
    return count;
}
unsigned int queue_clear (struct queue* container){
    my_assert(container != NULL);
    int count = 0;
    while (container->first != NULL) {
        struct instruction *temp = container->first;
        container->first = container->first->next;
        free(temp);
        count++;
    }
    container->first = NULL;
    container->last = NULL;
    return count;
}