1. -- 
  2. -- Uwe R. Zimmer, Australia, 2013 
  3. -- 
  4.  
  5. package body Queue_Pack_Object_Base is 
  6.  
  7.    procedure Enqueue (Item : Element; Queue : in out Queue_Type) is 
  8.    begin 
  9.       if Is_Full (Queue) then 
  10.          raise Queue_overflow; 
  11.       end if; 
  12.       Queue.Elements (Queue.Free) := Item; 
  13.       Queue.Free     := Queue.Free + 1; 
  14.       Queue.Is_Empty := False; 
  15.    end Enqueue; 
  16.  
  17.    procedure Dequeue (Item : out Element; Queue : in out Queue_Type) is 
  18.    begin 
  19.       if Is_Empty (Queue) then 
  20.          raise Queue_underflow; 
  21.       end if; 
  22.       Item      := Queue.Elements (Queue.Top); 
  23.       Queue.Top := Queue.Top + 1; 
  24.       Queue.Is_Empty := Queue.Top = Queue.Free; 
  25.    end Dequeue; 
  26.  
  27.    function Is_Empty (Queue : Queue_Type) return Boolean is 
  28.      (Queue.Is_Empty); 
  29.  
  30.    function Is_Full (Queue : Queue_Type) return Boolean is 
  31.      (not Queue.Is_Empty and then Queue.Top = Queue.Free); 
  32.  
  33. end Queue_Pack_Object_Base;