TFildOffsets = class
    type TOffsets = array of Integer;
    procedure Add(aOffset:Integer; var aOffsets:TOffsets);
    procedure Fild(var aFild:Integer; var aOffsets:TOffsets); overload;
    procedure Fild(var aFild:Double;  var aOffsets:TOffsets); overload;
  end;

  TFilds = class(TFildOffsets)
    A : Integer;
    D : Double;
    class var Offsets:TFildOffsets.TOffsets;
    class constructor Init;
  end;

{ TFildOffsets }

procedure TFildOffsets.Add(aOffset: Integer; var aOffsets: TOffsets);
begin
  SetLength(aOffsets, Length(aOffsets)+1);
  aOffsets[Length(aOffsets)-1] := aOffset;
end;

procedure TFildOffsets.Fild(var aFild: Integer; var aOffsets: TOffsets);
begin
  Add(PByte(@aFild) - PByte(Self), aOffsets);
end;

procedure TFildOffsets.Fild(var aFild: Double; var aOffsets: TOffsets);
begin
  Add(PByte(@aFild) - PByte(Self), aOffsets);
end;

{ TFilds }

class constructor TFilds.Init;
begin
  with TFilds(nil) do begin
    Fild(A, Offsets);
    Fild(D, Offsets);
  end;
end;