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pygments-main / tests / examplefiles / inet_pton6.dg

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re  = import!
sys = import!


# IPv6address    =  hexpart [ ":" IPv4address ]
# IPv4address    =  1*3DIGIT "." 1*3DIGIT "." 1*3DIGIT "." 1*3DIGIT
# hexpart        =  [ hexseq ] [ "::" [ hexseq ] ]
# hexseq         =  hex4 *( ":" hex4)
# hex4           =  1*4HEXDIG
hexpart = r'({0}|)(?:::({0}|)|)'.format r'(?:[\da-f]{1,4})(?::[\da-f]{1,4})*'
addrv4  = r'(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})'
addrv6  = re.compile $ r'(?i)(?:{})(?::{})?$'.format hexpart addrv4


# Parse a base-N number given a list of its digits.
#
# :param q: the number of digits in that numeral system
#
# :param digits: an iterable of integers in range [0..q]
#
# :return: a decimal integer
#
base_n = (q digits) -> foldl (x y) -> (x * q + y) 0 digits


# Parse a sequence of hexadecimal numbers
#
# :param q: a string of colon-separated base-16 integers
#
# :return: an iterable of Python ints
#
unhex = q -> q and map p -> (int p 16) (q.split ':')


# Parse an IPv6 address as specified in RFC 4291.
#
# :param address: a string, obviously.
#
# :return: an integer which, written in binary form, points to the same node.
#
inet_pton6 = address ->
  raise $ ValueError 'not a valid IPv6 address' unless match = addrv6.match address
  start, end, *ipv4 = match.groups!

  is_ipv4 = not $ None in ipv4
  shift   = (7 - start.count ':' - 2 * is_ipv4) * 16

  raise $ ValueError 'not a valid IPv6 address' if (end is None and shift) or shift < 0
  hexaddr = (base_n 0x10000 (unhex start) << shift) + base_n 0x10000 (unhex $ end or '')
  hexaddr unless is_ipv4 else (hexaddr << 32) + base_n 0x100 (map int ipv4)


inet6_type = q -> switch
  not q = 'unspecified'
  q == 1 = 'loopback'
  (q >>  32)              == 0x000000000000ffff = 'IPv4-mapped'
  (q >>  64)              == 0xfe80000000000000 = 'link-local'
  (q >> 120)              != 0x00000000000000ff = 'general unicast'
  (q >> 112) % (1 << 4)   == 0x0000000000000000 = 'multicast w/ reserved scope value'
  (q >> 112) % (1 << 4)   == 0x000000000000000f = 'multicast w/ reserved scope value'
  (q >> 112) % (1 << 4)   == 0x0000000000000001 = 'interface-local multicast'
  (q >> 112) % (1 << 4)   == 0x0000000000000004 = 'admin-local multicast'
  (q >> 112) % (1 << 4)   == 0x0000000000000005 = 'site-local multicast'
  (q >> 112) % (1 << 4)   == 0x0000000000000008 = 'organization-local multicast'
  (q >> 112) % (1 << 4)   == 0x000000000000000e = 'global multicast'
  (q >> 112) % (1 << 4)   != 0x0000000000000002 = 'multicast w/ unknown scope value'
  (q >>  24) % (1 << 112) == 0x00000000000001ff = 'solicited-node multicast'
  True = 'link-local multicast'


print $ (x -> (inet6_type x, hex x)) $ inet_pton6 $ sys.stdin.read!.strip!