queue

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

int queue_add(void* new_object, queue_object* queue){

    queue_object *new_el = malloc(sizeof(queue_object));

    if (new_object == NULL){
        return 1;
    }
    else
    {
        new_el->object = new_object;

        if(queue->next == NULL){
            queue->next = new_el;
            new_el->next = NULL;
        }
        else{

            queue_object *current_el = queue->next;
            queue_object *next_el;

            while(current_el->next != NULL){

                next_el = current_el->next;
                current_el = next_el;

            }

            current_el->next = new_el;
            new_el->next = NULL;
        }

     return 0;
    }
}

void* queue_poll(queue_object* queue){

    if(queue == NULL || queue->next == NULL){//wenn queue leer

        return NULL;
    }
    else{

        queue_object *prev_el = queue->next; //das zu loeschende element
        queue_object *next_el = prev_el->next; //das naechste element

        queue->next = next_el;

        void* obj = prev_el->object;
        free(prev_el); //letztes element loeschen

        return obj;
    }
}

queue_object* new_queue(){

    queue_object *head = malloc(sizeof(queue_object));
    head->next = NULL;
    head->object = NULL;

    return head;
}


void free_queue(queue_object* queue){

    if (queue == NULL){
        return;
    }
    else{

        queue_object *current_el = queue->next;
        queue_object *next_el;

        while(current_el != NULL){ //&current_el->next != NULL?
            next_el = current_el->next;
            free(current_el);
            current_el = next_el;
        }
    }
    free(queue);

}

void* queue_peek(queue_object* queue){

    if(queue == NULL || queue->next == NULL){//wenn queue leer

        return NULL;
    }
    else{
        queue_object *prev_el = queue->next;
        void* obj = prev_el->object;
        return obj;
    }
}