Category : Pascal Source Code
Archive   : PROD30S2.ZIP
Filename : QUELIB.INC

(*
* Copyright 1987, 1989 Samuel H. Smith; All rights reserved
*
* This is a component of the ProDoor System.
* Do not distribute modified versions without my permission.
* Do not remove or alter this notice or any other copyright notice.
* If you use this in your own program you must distribute source code.
* Do not use any of this in a commercial product.
*
*)

(*
* quelib.inc - Circular Queue library (3-1-89)
*
*)


(*
* INIT_QUE(queue)
*
*)

procedure init_que( var q: queue_rec);
begin
q.next_in := 1;
q.next_out := 1;
q.count := 0;
end;


(*
* EMPTY_QUE(queue): boolean
*
*)

function empty_que( var q: queue_rec ): boolean;
begin
empty_que := q.count = 0;
end;


(*
* QUE_FREE(queue): integer
*
*)

function que_free (var q: queue_rec): integer;
begin
que_free := queue_size - q.count;
end;


(*
* ENQUE(queue, char)
*
*)

procedure enque (var q: queue_rec; c: char);
begin
inc(q.count);
q.data[q.next_in] := c;
if q.next_in < queue_size then
inc(q.next_in)
else
q.next_in := 1;
end;


(*
* DEQUE(queue,dest)
* (EMPTY_QUE check is required before calling DEQUE)
*
*)

procedure deque (var q: queue_rec; var c: char);
begin
c := q.data[q.next_out];
if q.next_out < queue_size then
inc(q.next_out)
else
q.next_out := 1;
dec(q.count);
end;