22 TaggedObject = collections.namedtuple(
30 def _make_tag_only_serializer(tag, expected_value):
34 assert to.instance == expected_value
39 def _make_struct_serializer(fmt):
41 packer = functools.partial(struct.pack, fmt)
44 return packer(to.tag, to.instance)
48 def _make_string_serializer(encoder):
49 packer = functools.partial(struct.pack, '!BI')
52 encoded = encoder(to.instance)
53 return packer(to.tag, len(encoded)) + encoded
57 _TAGS_TO_SERIALIZERS = {
58 TAG_NULL: _make_tag_only_serializer(TAG_NULL, None),
59 TAG_TRUE: _make_tag_only_serializer(TAG_TRUE, True),
60 TAG_FALSE: _make_tag_only_serializer(TAG_FALSE, False),
61 TAG_UINT8: _make_struct_serializer('B'),
62 TAG_UINT16: _make_struct_serializer('H'),
63 TAG_UINT32: _make_struct_serializer('I'),
64 TAG_UINT64: _make_struct_serializer('Q'),
65 TAG_INT8: _make_struct_serializer('b'),
66 TAG_INT16: _make_struct_serializer('h'),
67 TAG_INT32: _make_struct_serializer('i'),
68 TAG_INT64: _make_struct_serializer('q'),
69 TAG_BINARY: _make_string_serializer(lambda s: s),
70 TAG_UTF8: _make_string_serializer(lambda s: s.encode('utf-8')),
71 TAG_UTF16: _make_string_serializer(lambda s: s.encode('utf-16')),
72 TAG_UTF32: _make_string_serializer(lambda s: s.encode('utf-32')),
76 return _TAGS_TO_SERIALIZERS[to.tag](to)
78 def _make_tag_only_parser(tag, value):
80 return TaggedObject(tag = tag, instance = value)
84 def _make_struct_deserializer(tag, fmt):
86 size = struct.calcsize(fmt)
87 unpacker = functools.partial(struct.unpack, fmt)
92 return TaggedObject(tag = tag, instance = unpacker(b)[0])
96 def _make_string_deserializer(tag, decoder):
98 size = struct.calcsize(fmt)
99 unpacker = functools.partial(struct.unpack, fmt)
102 length_b = b.read(size)
103 assert len(length_b) == size
104 length = unpacker(length_b)[0]
106 assert len(s) == length
107 return TaggedObject(tag = tag, instance = decoder(s))
112 TAG_NULL: _make_tag_only_parser(TAG_NULL, None),
113 TAG_TRUE: _make_tag_only_parser(TAG_TRUE, True),
114 TAG_FALSE: _make_tag_only_parser(TAG_FALSE, False),
115 TAG_UINT8: _make_struct_deserializer(TAG_UINT8, 'B'),
116 TAG_UINT16: _make_struct_deserializer(TAG_UINT16, 'H'),
117 TAG_UINT32: _make_struct_deserializer(TAG_UINT32, 'I'),
118 TAG_UINT64: _make_struct_deserializer(TAG_UINT64, 'Q'),
119 TAG_INT8: _make_struct_deserializer(TAG_INT8, 'b'),
120 TAG_INT16: _make_struct_deserializer(TAG_INT16, 'h'),
121 TAG_INT32: _make_struct_deserializer(TAG_INT32, 'i'),
122 TAG_INT64: _make_struct_deserializer(TAG_INT64, 'q'),
123 TAG_BINARY: _make_string_deserializer(TAG_BINARY, lambda b: b),
124 TAG_UTF8: _make_string_deserializer(TAG_UTF8, lambda b: b.decode('utf-8')),
125 TAG_UTF16: _make_string_deserializer(TAG_UTF16, lambda b: b.decode('utf-16')),
126 TAG_UTF32: _make_string_deserializer(TAG_UTF32, lambda b: b.decode('utf-32')),
130 if isinstance(b, bytes):
135 result = _TAGS_TO_PARSERS[tag](b)
139 if len(remainder) == 0:
142 raise Exception('Unable to parse remainder: {}'.format(remainder))