defmodule InetAton do
  @moduledoc """
  Converts the IP address from the IPv4 numbers-and-dots notation into a "hostlong" in network byte order

  Ported from https://gist.github.com/marcelog/8b5fe7d3aaa83eca2d0f
  """

  @doc """
  iex> InetAton.convert("127.0.0.1")
  2130706433
  """
  @spec convert(binary) :: pos_integer()
  def convert(ip_address) do
    [p1, p2, p3, p4] = String.split(ip_address, ".")
    b1 = Bitwise.bsl(String.to_integer(p1), 24)
    b2 = Bitwise.bsl(String.to_integer(p2), 16)
    b3 = Bitwise.bsl(String.to_integer(p3), 8)
    b4 = String.to_integer(p4)
    b1 + b2 + b3 + b4
  end
end