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1#!/usr/bin/env python3
2#
3#  Copyright (c) 2019, The OpenThread Authors.
4#  All rights reserved.
5#
6#  Redistribution and use in source and binary forms, with or without
7#  modification, are permitted provided that the following conditions are met:
8#  1. Redistributions of source code must retain the above copyright
9#     notice, this list of conditions and the following disclaimer.
10#  2. Redistributions in binary form must reproduce the above copyright
11#     notice, this list of conditions and the following disclaimer in the
12#     documentation and/or other materials provided with the distribution.
13#  3. Neither the name of the copyright holder nor the
14#     names of its contributors may be used to endorse or promote products
15#     derived from this software without specific prior written permission.
16#
17#  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
18#  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19#  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20#  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
21#  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
22#  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23#  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24#  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
25#  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26#  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
27#  POSSIBILITY OF SUCH DAMAGE.
28
29import io
30import logging
31
32
33class UnknownTlv(object):
34
35    def __init__(self, type, data):
36        self.type = type
37        self.data = data
38
39    def __repr__(self):
40        return 'UnknownTlv(%d, %s)' % (self.type, self.data)
41
42
43class UnknownTlvFactory(object):
44
45    def __init__(self, type):
46        self._type = type
47
48    def parse(self, data, message_info):
49        return UnknownTlv(self._type, data)
50
51
52class SubTlvsFactory(object):
53
54    def __init__(self, sub_tlvs_factories):
55        self._sub_tlvs_factories = sub_tlvs_factories
56
57    def _get_factory(self, _type):
58        try:
59            return self._sub_tlvs_factories[_type]
60        except KeyError:
61            logging.error('Could not find TLV factory. Unsupported TLV type: {}'.format(_type))
62            return UnknownTlvFactory(_type)
63
64    def parse(self, data, message_info):
65        sub_tlvs = []
66
67        while data.tell() < len(data.getvalue()):
68            _type = ord(data.read(1))
69
70            length = ord(data.read(1))
71            value = data.read(length)
72
73            factory = self._get_factory(_type)
74
75            message_info.length = length
76            tlv = factory.parse(io.BytesIO(value), message_info)
77
78            sub_tlvs.append(tlv)
79
80        return sub_tlvs
81