CRC32 in succinct F#

gistfile1.fs

  let IEEE = 0xedb88320u

  /// The seed value default: all ones, CRC depends fully on its input.
  let seed = 0xffffffffu

  let inline (!!) v = v ^^^ 0xFFFFFFFFu

  let crc_table = Array.init 256 (fun i ->
    (uint32 i, [0..7])
    ||> List.fold (fun value _ ->
      match value &&& 1u with
      | 0u -> value >>> 1
      | _  -> (value >>> 1) ^^^ IEEE))

  let step state buffer =
    (state, buffer)
    ||> Array.fold (fun crc byt -> crc_table.[int(byt ^^^ byte crc)] ^^^ (crc >>> 8))

  let finalise (state : uint32) : byte [] =
    !! state |> BigEndian.uint32_to_bytes_mem

  let single_step = finalise << step seed