def irc_upcase!(irc_string, casemapping = :rfc1459)
      case casemapping
      when :ascii
        irc_string.tr!(*@@ascii_map)
      when :rfc1459
        irc_string.tr!(*@@rfc1459_map)
      when :'strict-rfc1459'
        irc_string.tr!(*@@strict_rfc1459_map)
      else
        raise ArgumentError, "Unsupported casemapping #{casemapping}"
      end

      return irc_string
    end
def irc_upcase!(irc_string, casemapping = :rfc1459)
      case casemapping
      when :ascii
        irc_string.tr!(*@@ascii_map)
      when :rfc1459
        irc_string.tr!(*@@rfc1459_map)
      when :'strict-rfc1459'
        irc_string.tr!(*@@strict_rfc1459_map)
      else
        raise ArgumentError, "Unsupported casemapping #{casemapping}"
      end

      return irc_string
    end
Turn a string into IRC upper case, modifying it in place.
 @param [String] irc_string An IRC string (nickname, channel, etc).
 @param [Symbol] casemapping An IRC casemapping.
 @return [String] An upper case version of the IRC string according to
   the casemapping.