package body Queue is

   ----------------------------------------------------------------------------
   procedure Enqueue (Queue : in out Queue_Type;
                      Item  : in     Element_Type) is
   begin
      if Queue.Count = Queue.Max_Size then
        raise OVERFLOW;
      else
        Queue.Rear := Queue.Rear rem Queue.Max_Size + 1;
        Queue.Items(Queue.Rear) := Item;
        Queue.Count := Queue.Count + 1;
      end if;
   end Enqueue;

   ----------------------------------------------------------------------------
   procedure Dequeue (Queue : in out Queue_Type;
                      Item  :    out Element_Type) is
   begin
      if Queue.Count = 0 then
        raise UNDERFLOW;
      else
        Item := Queue.Items(Queue.Front);
        Queue.Front := Queue.Front rem Queue.Max_Size + 1;
        Queue.Count := Queue.Count - 1;
      end if;
   end Dequeue;

   ----------------------------------------------------------------------------
   function Full (Queue : in Queue_Type) return Boolean is
   begin
      return Queue.Count = Queue.Max_Size;
   end Full;

   ----------------------------------------------------------------------------
   function Empty (Queue : in Queue_Type) return Boolean is
   begin
      return Queue.Count = 0;
   end Empty;

   --------------------------------------------------------------------------
   procedure Clear (Queue : in out Queue_Type) is
   begin
      Queue.Count := 0;
      Queue.Front := 1;
      Queue.Rear  := Queue.Max_Size;
   end Clear;

end Queue;