MessagePack Time extension unpacker in Ruby

time-extension-msgpack.rb

require "msgpack"

class DateTimeExtension
  def self.unpack(data)
    case data.size
    when 4
      seconds = data.unpack("N")[0]
      Time.at(seconds).utc

    when 8
      nanoseconds, seconds =
        data.unpack("B30B34").map do |bitstring|
          bitstring.to_i(2)
        end

      Time.at(seconds, nanoseconds / 1_000).utc

    when 16
      nanoseconds, seconds = data.unpack("NQ")
      Time.at(seconds, nanoseconds / 1_000).utc
    end
  end
end

MessagePack::DefaultFactory.register_type(-1, DateTimeExtension, unpacker: :unpack)