Category : Pascal Source Code
Archive   : PROD30S2.ZIP
Filename : BITMAP.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.
*
*)

(*
* bitmap.inc - Library to BitMap manipulation functions
*
*)

(* --------------------------------------------------------- *)
function getbit(map: bitmap; bitnum: bitnumber): boolean;
{return true/false for specified bit 0..39 in a bitmap}
var
byteno: integer;
bitno: integer;
begin
byteno := bitnum shr 3; {0..4}
bitno := bitnum mod 8; {0..7}
getbit := odd(map.bits[byteno] shr bitno);
end;

(* --------------------------------------------------------- *)
procedure setbit(var map: bitmap; bitnum: bitnumber; value: boolean);
{set the specified bit in a bitmap}
var
byteno: integer;
bitno: integer;
begin
byteno := bitnum shr 3; {0..4}
bitno := bitnum mod 8; {0..7}
if value then
map.bits[byteno] := map.bits[byteno] or (1 shl bitno)
else
map.bits[byteno] := map.bits[byteno] and (255 - (1 shl bitno));
end;