def to_s
str = to_string
return str if ipv4?
str.gsub!(/\b0{1,3}([\da-f]+)\b/i, '\1')
loop do
break if str.sub!(/\A0:0:0:0:0:0:0:0\Z/, '::')
break if str.sub!(/\b0:0:0:0:0:0:0\b/, ':')
break if str.sub!(/\b0:0:0:0:0:0\b/, ':')
break if str.sub!(/\b0:0:0:0:0\b/, ':')
break if str.sub!(/\b0:0:0:0\b/, ':')
break if str.sub!(/\b0:0:0\b/, ':')
break if str.sub!(/\b0:0\b/, ':')
break
end
str.sub!(/:{3,}/, '::')
if /\A::(ffff:)?([\da-f]{1,4}):([\da-f]{1,4})\Z/i =~ str
str = sprintf('::%s%d.%d.%d.%d', $1, $2.hex / 256, $2.hex % 256, $3.hex / 256, $3.hex % 256)
end
str
end