The World of Computer Software/The World of Computer Software.iso/tcsel003.zip/BITMAP.PAS

Pascal/Delphi Source File | 1992-10-16 | 871b | 31 lines

type
  map = array[0..maxsize] of byte;

function BitSetInBitMap(var x; numb : longint): boolean;
  { Tests the numb bit in the bitmap array }
  var m: map absolute x;
  begin
    BitSetInBitMap := odd(m[numb shr 3] shr (numb and 7));
  end;

procedure SetBitInBitMap(var x; numb: word);
  { Sets the numb bit in the bitmap array }
  var m: map absolute x;
  begin
    m[numb shr 3] := m[numb shr 3] or (1 shl (numb and 7))
  end;

procedure ResetBitInBitMap(var x; numb : longint);
  { Resets the numb bit in the bitmap array }
  var m: map absolute x;
  begin
   m[numb shr 3] := m[numb shr 3] and not(1 shl (numb and 7));
  end;

procedure ToggleBitInBitMap(var x; numb : longint);
  { Toggles (flips) the numb bit in the bitmap array }
  var m: map absolute x;
  begin
    m[numb shr 3] := m[numb shr 3] xor (1 shl (numb and 7));
  end;