/*********************************************************************/
/* Name: Insert_event                                                   */
/* Description                                                          */
/*    This procedure will insert the simulation event into a doubly     */
/*    linked queue.  The parameters are as follows:                     */
/*     etype - type of event to be inserted.                            */
/*     etime - the time the event will occur.                        */
/*     custind - index of the customer associated with this event.      */
/* The following steps are performed:                                   */
/*     1 - get a free node and add the event information.               */
/*     2 - insert node into the proper place in the queue.              */
/*         2a - into an empty queue.                                    */
/*         2b - at the top of the queue.                                */
/*         2c - at the bottom of the queue.                             */
/*         2d - regular insertion (someplace in the middle).            */
/*********************************************************************/
void Insert_event(int etype, long int etime,struct Custs *custind)
  {
  int not_found;
  struct event_node *loc, *pos;
  loc = (struct event_node *) malloc(sizeof (struct event_node));
 /* add the information to the structure */
  loc->ev_type = etype;
  loc->ev_time = etime;
  loc->cust_index = custind;
  loc->forward = NULL;
  loc->backward = NULL;
 /* determine if the list is empty */
  if(top_event == NULL)
         {
         top_event = loc;
         last_event = loc;
         return;
         }
  /* see if it belongs on top */
   if(top_event->ev_time > etime)
         {
         top_event->backward = loc;
         loc->forward = top_event;
         top_event = loc;
         return;
         }
 /* see if it belongs at the bottom */
  if(last_event->ev_time <= etime)
         {
         last_event->forward = loc;
         loc->backward = last_event;
         last_event = loc;
         return;
         }
 /* it belongs somewhere in the middle so find its place */
  not_found = TRUE;
  pos = top_event;
  while(pos != NULL && not_found)
         {
        if(pos->ev_time > etime)
                not_found = FALSE;
         else
                pos = pos->forward;
         }
  /* check to see if we found something as we should have */
  if(not_found)
         {
         printf(" ***Error - problems in insert event routine***\n");
         return;
         }
  /* add node to appropriate place */
  loc->forward = pos;
  loc->backward = pos->backward;
  (pos->backward)->forward = loc;
  pos->backward = loc;
  return;
}