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# -----------------------------------------------------------------------------
# Copyright (c) 2008 by David P. D. Moss. All rights reserved.
#
# Released under the BSD license. See the LICENSE file for details.
# -----------------------------------------------------------------------------
"""A basic implementation of RFC 1924 ;-)"""
from netaddr.core import AddrFormatError
from netaddr.ip import IPAddress
def chr_range(low, high):
"""Returns all characters between low and high chars."""
return [chr(i) for i in range(ord(low), ord(high) + 1)]
#: Base 85 integer index to character lookup table.
BASE_85 = (
chr_range('0', '9')
+ chr_range('A', 'Z')
+ chr_range('a', 'z')
+ [
'!',
'#',
'$',
'%',
'&',
'(',
')',
'*',
'+',
'-',
';',
'<',
'=',
'>',
'?',
'@',
'^',
'_',
'`',
'{',
'|',
'}',
'~',
]
)
#: Base 85 digit to integer lookup table.
BASE_85_DICT = dict(zip(BASE_85, range(0, 86)))
def ipv6_to_base85(addr):
"""Convert a regular IPv6 address to base 85."""
ip = IPAddress(addr)
int_val = int(ip)
remainder = []
while int_val > 0:
remainder.append(int_val % 85)
int_val //= 85
encoded = ''.join([BASE_85[w] for w in reversed(remainder)])
leading_zeroes = (20 - len(encoded)) * '0'
return leading_zeroes + encoded
def base85_to_ipv6(addr):
"""
Convert a base 85 IPv6 address to its hexadecimal format.
"""
tokens = list(addr)
if len(tokens) != 20:
raise AddrFormatError('Invalid base 85 IPv6 address: %r' % (addr,))
result = 0
for i, num in enumerate(reversed(tokens)):
num = BASE_85_DICT[num]
result += num * 85**i
ip = IPAddress(result, 6)
return str(ip)
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