SJN

#include "SJN.h"

static queue_object* SJN_queue;
//You can add more global variables here

int bedienzeit(queue_object* current_object){

    process* current_process = current_object->object;
    int current_start_time = current_process->start_time;
    int current_time_left = current_process->time_left;

    return current_start_time+current_time_left;

}

void* poll_lowest_time(queue_object* queue){

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

    queue_object *prev_old; //das element vor dem zu loeschenden element

    queue_object *old; //das zu loeschende element
    void* obj;

    int time = 100;

    if (current_el->next == NULL){ //ein element in der warteschlange
        queue->next = NULL;
        obj = current_el->object;
        free(current_el);
    }
    else{
        while(current_el!=NULL){

            int current_bedienzeit = bedienzeit(current_el);

            if(current_bedienzeit < time){

                time = current_bedienzeit;
                prev_old = prev_el;
                old = current_el;
            }
            prev_el=prev_el->next;
            current_el=current_el->next;
        }
        obj = old->object;
        prev_old->next = old->next;
        free(old);
    }
    return obj;
}

process* SJN_tick (process* running_process){

   if (running_process == NULL){ //den ersten prozess aus der schlange nehmen

        running_process = queue_poll(SJN_queue);
    }

    if( running_process->time_left==0){

        running_process = poll_lowest_time(SJN_queue);
    }

    if (running_process != NULL){

        running_process->time_left--;
    }

    return running_process;
}

int SJN_startup(){

    SJN_queue=new_queue();
    if (SJN_queue==NULL){
        return 1;
    }
    return 0;
}

process* SJN_new_arrival(process* arriving_process, process* running_process){
    if(arriving_process!=NULL){

                queue_add(arriving_process, SJN_queue);

    }
    return running_process;
}

void SJN_finish(){

    free(SJN_queue);
}