function GetRecordSize(types: array of TxType; Alignment: Integer): Integer;
var
  i: integer;
  max: integer;
begin
  max := 0;
  for i := low(types) to high(types) do
  case types[i] of
    xInteger: if max < 4 then max := 4;
    xByte: if max < 1 then max := 1;
    xDouble: if max < 8 then max := 8;
    xExtended: if max < 10 then max := 10;
    xWord: if max < 2 then max := 2;
  end;
  if max < Alignment then
    Alignment := max;

  result := 0;
  for i := low(types) to high (types) do
  case types[i] of
    xInteger: if result mod 4 = 0 then inc(result,4) else inc (result,4 + alignment-(result mod alignment+1));
    xByte: if result mod 1 = 0 then inc(result,1) else inc (result,1 + alignment-(result mod alignment+1));
    xDouble: if result mod 8 = 0 then inc(result,8) else inc (result,8 + alignment-(result mod alignment+1));
    xExtended: if result mod 10 = 0 then inc(result,10) else inc (result,10 + alignment-(result mod alignment+1));
    xWord: if result mod 2 = 0 then inc(result,2) else inc (result,2 + alignment-(result mod alignment+1));
  end;
  if result mod alignment <> 0 then
    result := result + alignment-(result mod alignment);
end;

type b = record
  b: byte;
  a: extended;
  i: integer;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  form1.caption := inttostr(GetRecordSize([xByte, xExtended, xInteger],8))+' '+inttostr(SizeOf(b))