IP::V6

# File lib/ip/base.rb, line 303
def self.parse(str)
  case str
  when /\A\[?::(ffff:)?(\d+\.\d+\.\d+\.\d+)\]?(?:\/(\d+))?(?:@(.*))?\z/
    mapped = $1
    pfxlen = ($3 || 128).to_i
    ctx = $4
    return nil if pfxlen > 128
    v4 = (V4.parse($2) || return).to_i
    v4 |= 0xffff00000000 if mapped
    new(v4, pfxlen, ctx)
  when /\A\[?([0-9a-f:]+)\]?(?:\/(\d+))?(?:@(.*))?\z/
    addr = $1
    pfxlen = ($2 || 128).to_i
    return nil if pfxlen > 128
    ctx = $3
    return nil if pfxlen > 128
    if addr =~ /\A(.*?)::(.*)\z/
      left, right = $1, $2
      l = left.split(':')
      r = right.split(':')
      rest = 8 - l.length - r.length
      return nil if rest < 0
    else
      l = addr.split(':')
      r = []
      rest = 0
      return nil if l.length != 8
    end
    out = ""
    l.each { |quad| return nil if quad.length>4; out << quad.rjust(4,"0") }
    rest.times { out << "0000" }
    r.each { |quad| return nil if quad.length>4; out << quad.rjust(4,"0") }
    new(out, pfxlen, ctx)
  else
    nil
  end
end

# File lib/ip/base.rb, line 364
def ipv4_compat?
  @addr > 1 && (@addr >> 32) == 0
end

# File lib/ip/base.rb, line 360
def ipv4_mapped?
  (@addr >> 32) == 0xffff
end

# File lib/ip/base.rb, line 369
def native
  return self unless (ipv4_mapped? || ipv4_compat?) && (@pfxlen >= 96)
  V4.new(@addr & V4::MASK, @pfxlen - 96, @ctx)
end

# File lib/ip/base.rb, line 342
def to_addr
  if ipv4_compat?
    "::#{native.to_addr}"
  elsif ipv4_mapped?
    "::ffff:#{native.to_addr}"
  elsif @addr.zero?
    "::"
  else
    res = to_hex.scan(/..../).join(':')
    res.gsub!(/\b0{1,3}/,'')
    res.sub!(/\b0:0:0:0(:0)*\b/,':') ||
      res.sub!(/\b0:0:0\b/,':') ||
      res.sub!(/\b0:0\b/,':')
    res.sub!(/:::+/,'::')
    res
  end
end