my_binary_parser.ex

defmodule MyBinaryParser do

  # Parsing a 2 byte binary to float16
  # according to: https://en.wikipedia.org/wiki/Half-precision_floating-point_format
  # Float16 is build in OTP 24.
  def parse_float16(<<sign::1, exponent::5, significand::10>>) do

    case {sign, exponent, significand} do

      {0b0, 0b00000, 0b0000000000} ->
        0.0
      {0b1, 0b00000, 0b0000000000} ->
        -0.0

      {sign, 0b00000, significand} ->
        # Subnormal numbers
        :math.pow(-1, sign) * :math.pow(2, -14) * (0 + (significand / 1024))

      {0b0, 0b11111, 0b0000000000} ->
        :infinity_positive
      {0b1, 0b11111, 0b0000000000} ->
        :infinity_negative
      {_, 0b11111, _} ->
        :nan

      {sign, exponent, significand} ->
        # Normalized values
        :math.pow(-1, sign) * :math.pow(2, exponent-15) * (1 + (significand / 1024))
    end
  end

end