Moved binary into a submodule

[sandbox] / serial / serial / binary.py

diff --git a/serial/serial/binary.py b/serial/serial/binary.py
new file mode 100644 (file)
index 0000000..fabcd47
--- /dev/null
+++ b/serial/serial/binary.py
@@ -0,0 +1,182 @@
+import collections
+import functools
+import io
+import struct
+
+TAG_NULL = 0x00
+TAG_TRUE = 0x01
+TAG_FALSE = 0x02
+TAG_UINT8 = 0x03
+TAG_UINT16 = 0x04
+TAG_UINT32 = 0x05
+TAG_UINT64 = 0x06
+TAG_INT8 = 0x10
+TAG_INT16 = 0x11
+TAG_INT32 = 0x12
+TAG_INT64 = 0x13
+TAG_BINARY = 0x20
+TAG_UTF8 = 0x21
+TAG_UTF16 = 0x22
+TAG_UTF32 = 0x23
+TAG_TUPLE = 0x30
+
+TaggedObject = collections.namedtuple(
+    'TaggedObject',
+    [
+        'tag',
+        'instance',
+    ],
+)
+
+def _make_tag_only_serializer(tag, expected_value):
+    tag = bytes([tag])
+
+    def serializer(to):
+        assert to.instance == expected_value
+        return tag
+
+    return serializer
+
+def _make_struct_serializer(fmt):
+    fmt = '!B' + fmt
+    packer = functools.partial(struct.pack, fmt)
+
+    def serializer(to):
+        return packer(to.tag, to.instance)
+
+    return serializer
+
+def _make_string_serializer(encoder):
+    packer = functools.partial(struct.pack, '!BI')
+
+    def serializer(to):
+        encoded = encoder(to.instance)
+        return packer(to.tag, len(encoded)) + encoded
+
+    return serializer
+
+def _serialize_tuple(to):
+    assert isinstance(to.instance, tuple)
+
+    payload = b''.join(serialize(item) for item in to.instance)
+
+    fmt = '!BI'
+
+    return struct.pack('!BI', TAG_TUPLE, len(payload)) + payload
+
+
+_TAGS_TO_SERIALIZERS = {
+    TAG_NULL: _make_tag_only_serializer(TAG_NULL, None),
+    TAG_TRUE: _make_tag_only_serializer(TAG_TRUE, True),
+    TAG_FALSE: _make_tag_only_serializer(TAG_FALSE, False),
+    TAG_UINT8: _make_struct_serializer('B'),
+    TAG_UINT16: _make_struct_serializer('H'),
+    TAG_UINT32: _make_struct_serializer('I'),
+    TAG_UINT64: _make_struct_serializer('Q'),
+    TAG_INT8: _make_struct_serializer('b'),
+    TAG_INT16: _make_struct_serializer('h'),
+    TAG_INT32: _make_struct_serializer('i'),
+    TAG_INT64: _make_struct_serializer('q'),
+    TAG_BINARY: _make_string_serializer(lambda s: s),
+    TAG_UTF8: _make_string_serializer(lambda s: s.encode('utf-8')),
+    TAG_UTF16: _make_string_serializer(lambda s: s.encode('utf-16')),
+    TAG_UTF32: _make_string_serializer(lambda s: s.encode('utf-32')),
+    TAG_TUPLE: _serialize_tuple,
+}
+
+def serialize(to):
+    return _TAGS_TO_SERIALIZERS[to.tag](to)
+
+def _make_tag_only_parser(tag, value):
+    def parser(b):
+        return 0, TaggedObject(tag = tag, instance = value)
+
+    return parser
+
+def _make_struct_deserializer(tag, fmt):
+    fmt = '!' + fmt
+    size = struct.calcsize(fmt)
+    unpacker = functools.partial(struct.unpack, fmt)
+
+    def parser(b):
+        b = b.read(size)
+        assert len(b) == size
+        return size, TaggedObject(tag = tag, instance = unpacker(b)[0])
+
+    return parser
+
+_LENGTH_FMT = '!I'
+_LENGTH_FMT_SIZE = struct.calcsize(_LENGTH_FMT)
+
+def _read_length_then_payload(b):
+    length_b = b.read(_LENGTH_FMT_SIZE)
+    assert len(length_b) == _LENGTH_FMT_SIZE
+    length = struct.unpack(_LENGTH_FMT, length_b)[0]
+
+    payload = b.read(length)
+    assert len(payload) == length
+    return _LENGTH_FMT_SIZE + length, payload
+
+def _make_string_deserializer(tag, decoder):
+    fmt = '!I'
+    size = struct.calcsize(fmt)
+    unpacker = functools.partial(struct.unpack, fmt)
+
+    def parser(b):
+        bytes_read, payload = _read_length_then_payload(b)
+        return bytes_read, TaggedObject(tag = tag, instance = decoder(payload))
+
+    return parser
+
+def _deserialize_tuple(b):
+    bytes_read, payload = _read_length_then_payload(b)
+
+    payload_stream = io.BytesIO(payload)
+
+    total_bytes_read = 0
+    instance = []
+
+    while total_bytes_read < len(payload):
+        partial_bytes_read, item = _deserialize_partial(payload_stream)
+        total_bytes_read += partial_bytes_read
+        instance.append(item)
+
+    return bytes_read, TaggedObject(tag = TAG_TUPLE, instance = tuple(instance))
+
+_TAGS_TO_PARSERS = {
+    TAG_NULL: _make_tag_only_parser(TAG_NULL, None),
+    TAG_TRUE: _make_tag_only_parser(TAG_TRUE, True),
+    TAG_FALSE: _make_tag_only_parser(TAG_FALSE, False),
+    TAG_UINT8: _make_struct_deserializer(TAG_UINT8, 'B'),
+    TAG_UINT16: _make_struct_deserializer(TAG_UINT16, 'H'),
+    TAG_UINT32: _make_struct_deserializer(TAG_UINT32, 'I'),
+    TAG_UINT64: _make_struct_deserializer(TAG_UINT64, 'Q'),
+    TAG_INT8: _make_struct_deserializer(TAG_INT8, 'b'),
+    TAG_INT16: _make_struct_deserializer(TAG_INT16, 'h'),
+    TAG_INT32: _make_struct_deserializer(TAG_INT32, 'i'),
+    TAG_INT64: _make_struct_deserializer(TAG_INT64, 'q'),
+    TAG_BINARY: _make_string_deserializer(TAG_BINARY, lambda b: b),
+    TAG_UTF8: _make_string_deserializer(TAG_UTF8, lambda b: b.decode('utf-8')),
+    TAG_UTF16: _make_string_deserializer(TAG_UTF16, lambda b: b.decode('utf-16')),
+    TAG_UTF32: _make_string_deserializer(TAG_UTF32, lambda b: b.decode('utf-32')),
+    TAG_TUPLE: _deserialize_tuple,
+}
+
+def _deserialize_partial(b):
+    tag = b.read(1)
+    assert len(tag) == 1
+    bytes_read, to = _TAGS_TO_PARSERS[tag[0]](b)
+    return bytes_read + 1, to
+
+def deserialize(b):
+    if isinstance(b, bytes):
+        b = io.BytesIO(b)
+
+    bytes_read, result = _deserialize_partial(b)
+
+    remainder = b.read()
+
+    if len(remainder) == 0:
+        return result
+
+    raise Exception('Unable to parse remainder: {}'.format(remainder))