23 TaggedObject = collections.namedtuple(
31 def _make_tag_only_serializer(tag, expected_value):
35 assert to.instance == expected_value
40 def _make_struct_serializer(fmt):
42 packer = functools.partial(struct.pack, fmt)
45 return packer(to.tag, to.instance)
49 def _make_string_serializer(encoder):
50 packer = functools.partial(struct.pack, '!BI')
53 encoded = encoder(to.instance)
54 return packer(to.tag, len(encoded)) + encoded
58 def _serialize_tuple(to):
59 assert isinstance(to.instance, tuple)
61 payload = b''.join(serialize(item) for item in to.instance)
65 return struct.pack('!BI', TAG_TUPLE, len(payload)) + payload
68 _TAGS_TO_SERIALIZERS = {
69 TAG_NULL: _make_tag_only_serializer(TAG_NULL, None),
70 TAG_TRUE: _make_tag_only_serializer(TAG_TRUE, True),
71 TAG_FALSE: _make_tag_only_serializer(TAG_FALSE, False),
72 TAG_UINT8: _make_struct_serializer('B'),
73 TAG_UINT16: _make_struct_serializer('H'),
74 TAG_UINT32: _make_struct_serializer('I'),
75 TAG_UINT64: _make_struct_serializer('Q'),
76 TAG_INT8: _make_struct_serializer('b'),
77 TAG_INT16: _make_struct_serializer('h'),
78 TAG_INT32: _make_struct_serializer('i'),
79 TAG_INT64: _make_struct_serializer('q'),
80 TAG_BINARY: _make_string_serializer(lambda s: s),
81 TAG_UTF8: _make_string_serializer(lambda s: s.encode('utf-8')),
82 TAG_UTF16: _make_string_serializer(lambda s: s.encode('utf-16')),
83 TAG_UTF32: _make_string_serializer(lambda s: s.encode('utf-32')),
84 TAG_TUPLE: _serialize_tuple,
88 return _TAGS_TO_SERIALIZERS[to.tag](to)
90 def _make_tag_only_parser(tag, value):
92 return 0, TaggedObject(tag = tag, instance = value)
96 def _make_struct_deserializer(tag, fmt):
98 size = struct.calcsize(fmt)
99 unpacker = functools.partial(struct.unpack, fmt)
103 assert len(b) == size
104 return size, TaggedObject(tag = tag, instance = unpacker(b)[0])
109 _LENGTH_FMT_SIZE = struct.calcsize(_LENGTH_FMT)
111 def _read_length_then_payload(b):
112 length_b = b.read(_LENGTH_FMT_SIZE)
113 assert len(length_b) == _LENGTH_FMT_SIZE
114 length = struct.unpack(_LENGTH_FMT, length_b)[0]
116 payload = b.read(length)
117 assert len(payload) == length
118 return _LENGTH_FMT_SIZE + length, payload
120 def _make_string_deserializer(tag, decoder):
122 size = struct.calcsize(fmt)
123 unpacker = functools.partial(struct.unpack, fmt)
126 bytes_read, payload = _read_length_then_payload(b)
127 return bytes_read, TaggedObject(tag = tag, instance = decoder(payload))
131 def _deserialize_tuple(b):
132 bytes_read, payload = _read_length_then_payload(b)
134 payload_stream = io.BytesIO(payload)
139 while total_bytes_read < len(payload):
140 partial_bytes_read, item = _deserialize_partial(payload_stream)
141 total_bytes_read += partial_bytes_read
142 instance.append(item)
144 return bytes_read, TaggedObject(tag = TAG_TUPLE, instance = tuple(instance))
147 TAG_NULL: _make_tag_only_parser(TAG_NULL, None),
148 TAG_TRUE: _make_tag_only_parser(TAG_TRUE, True),
149 TAG_FALSE: _make_tag_only_parser(TAG_FALSE, False),
150 TAG_UINT8: _make_struct_deserializer(TAG_UINT8, 'B'),
151 TAG_UINT16: _make_struct_deserializer(TAG_UINT16, 'H'),
152 TAG_UINT32: _make_struct_deserializer(TAG_UINT32, 'I'),
153 TAG_UINT64: _make_struct_deserializer(TAG_UINT64, 'Q'),
154 TAG_INT8: _make_struct_deserializer(TAG_INT8, 'b'),
155 TAG_INT16: _make_struct_deserializer(TAG_INT16, 'h'),
156 TAG_INT32: _make_struct_deserializer(TAG_INT32, 'i'),
157 TAG_INT64: _make_struct_deserializer(TAG_INT64, 'q'),
158 TAG_BINARY: _make_string_deserializer(TAG_BINARY, lambda b: b),
159 TAG_UTF8: _make_string_deserializer(TAG_UTF8, lambda b: b.decode('utf-8')),
160 TAG_UTF16: _make_string_deserializer(TAG_UTF16, lambda b: b.decode('utf-16')),
161 TAG_UTF32: _make_string_deserializer(TAG_UTF32, lambda b: b.decode('utf-32')),
162 TAG_TUPLE: _deserialize_tuple,
165 def _deserialize_partial(b):
168 bytes_read, to = _TAGS_TO_PARSERS[tag[0]](b)
169 return bytes_read + 1, to
172 if isinstance(b, bytes):
175 bytes_read, result = _deserialize_partial(b)
179 if len(remainder) == 0:
182 raise Exception('Unable to parse remainder: {}'.format(remainder))