int_to_bin_byte.ml

let int_to_bin_byte d =
  if d < 0 then invalid_arg "bin_of_int" else
  if d = 0 then "0" else
  let rec aux acc d =
    if d = 0 then acc else
    aux (string_of_int (d land 1) :: acc) (d lsr 1)
  in
  let res = String.concat "" (aux [] d) in
  if String.length res mod 8 <> 0 then
     String.make (8 - String.length res mod 8) '0' ^ res
  else res