type
  TTrimDirection = set of (tdLeft, tdRight);

function PATrimChars(const S: String; CS: TSysCharSet; Direction: TTrimDirection): String;
var
  i: Integer;
  L, Left, Right: Integer;
begin
  L := Length(S);

  Left := 1;
  if tdLeft in Direction then
  begin
    for i := 1 to L do
    begin
      if not (S[i] in CS) then
      begin
        Left := i;
        Break;
      end;
    end;
  end;

  Right := L;
  if dtRight in Direction then
  begin
    for i := L downto 1 do
    begin
      if not (S[i] in CS) then
      begin
        Right := i;
        Break;
      end;
    end;
  end;

  Result := Copy(S, Left, Right - Left + 1);
end;