new

# File lib/ipaddr.rb, line 402
  def initialize(addr = '::', family = Socket::AF_UNSPEC)
    if !addr.kind_of?(String)
      if family != Socket::AF_INET6 && family != Socket::AF_INET
        raise ArgumentError, "unsupported address family"
      end
      set(addr, family)
      @mask_addr = (family == Socket::AF_INET) ? IN4MASK : IN6MASK
      return
    end
    prefix, prefixlen = addr.split('/')
    if prefix =~ /^\[(.*)\]$/i
      prefix = $1
      family = Socket::AF_INET6
    end
    # It seems AI_NUMERICHOST doesn't do the job.
    #Socket.getaddrinfo(left, nil, Socket::AF_INET6, Socket::SOCK_STREAM, nil,
    #                  Socket::AI_NUMERICHOST)
    begin
      IPSocket.getaddress(prefix)               # test if address is vaild
    rescue
      raise ArgumentError, "invalid address"
    end
    @addr = @family = nil
    if family == Socket::AF_UNSPEC || family == Socket::AF_INET
      @addr = in_addr(prefix)
      if @addr
        @family = Socket::AF_INET
      end
    end
    if !@addr && (family == Socket::AF_UNSPEC || family == Socket::AF_INET6)
      @addr = in6_addr(prefix)
      @family = Socket::AF_INET6
    end
    if family != Socket::AF_UNSPEC && @family != family
      raise ArgumentError, "address family unmatch"
    end
    if prefixlen
      mask!(prefixlen)
    else
      @mask_addr = (@family == Socket::AF_INET) ? IN4MASK : IN6MASK
    end
  end