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✏️ Editing: euibase.py

# Copyright (C) 2015 Red Hat, Inc.
# Author: Petr Spacek <pspacek@redhat.com>
#
# Permission to use, copy, modify, and distribute this software and its
# documentation for any purpose with or without fee is hereby granted,
# provided that the above copyright notice and this permission notice
# appear in all copies.
#
# THE SOFTWARE IS PROVIDED 'AS IS' AND RED HAT DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

import binascii

import dns.rdata
from dns._compat import xrange

class EUIBase(dns.rdata.Rdata):

"""EUIxx record

@ivar fingerprint: xx-bit Extended Unique Identifier (EUI-xx)
    @type fingerprint: string
    @see: rfc7043.txt"""

__slots__ = ['eui']
    # define these in subclasses
    # byte_len = 6  # 0123456789ab (in hex)
    # text_len = byte_len * 3 - 1  # 01-23-45-67-89-ab

def __init__(self, rdclass, rdtype, eui):
        super(EUIBase, self).__init__(rdclass, rdtype)
        if len(eui) != self.byte_len:
            raise dns.exception.FormError('EUI%s rdata has to have %s bytes'
                                          % (self.byte_len * 8, self.byte_len))
        self.eui = eui

def to_text(self, origin=None, relativize=True, **kw):
        return dns.rdata._hexify(self.eui, chunksize=2).replace(' ', '-')

@classmethod
    def from_text(cls, rdclass, rdtype, tok, origin=None, relativize=True):
        text = tok.get_string()
        tok.get_eol()
        if len(text) != cls.text_len:
            raise dns.exception.SyntaxError(
                'Input text must have %s characters' % cls.text_len)
        expected_dash_idxs = xrange(2, cls.byte_len * 3 - 1, 3)
        for i in expected_dash_idxs:
            if text[i] != '-':
                raise dns.exception.SyntaxError('Dash expected at position %s'
                                                % i)
        text = text.replace('-', '')
        try:
            data = binascii.unhexlify(text.encode())
        except (ValueError, TypeError) as ex:
            raise dns.exception.SyntaxError('Hex decoding error: %s' % str(ex))
        return cls(rdclass, rdtype, data)

def to_wire(self, file, compress=None, origin=None):
        file.write(self.eui)

@classmethod
    def from_wire(cls, rdclass, rdtype, wire, current, rdlen, origin=None):
        eui = wire[current:current + rdlen].unwrap()
        return cls(rdclass, rdtype, eui)

MR SKB