_to_string

# File lib/ipaddr.rb, line 580
  def _to_string(addr)
    case @family
    when Socket::AF_INET
      return (0..3).map { |i|
        (addr >> (24 - 8 * i)) & 0xff
      }.join('.')
    when Socket::AF_INET6
      return (("%.32x" % addr).gsub!(/.{4}(?!$)/, '\&:'))
    else
      raise "unsupported address family"
    end
  end