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56 lines
1.4 KiB
56 lines
1.4 KiB
import bz2
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import io
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from a2s.byteio import ByteReader
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class A2SFragment:
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__slots__ = (
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"message_id",
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"fragment_count",
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"fragment_id",
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"mtu",
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"decompressed_size",
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"crc",
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"payload",
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)
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def __init__(
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self,
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message_id: int,
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fragment_count: int,
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fragment_id: int,
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mtu: int,
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decompressed_size: int = 0,
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crc: int = 0,
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payload: bytes = b"",
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) -> None:
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self.message_id: int = message_id
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self.fragment_count: int = fragment_count
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self.fragment_id: int = fragment_id
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self.mtu: int = mtu
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self.decompressed_size: int = decompressed_size
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self.crc: int = crc
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self.payload: bytes = payload
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@property
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def is_compressed(self) -> bool:
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return bool(self.message_id & (1 << 15))
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def decode_fragment(data: bytes) -> A2SFragment:
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reader = ByteReader(io.BytesIO(data), endian="<", encoding="utf-8")
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frag = A2SFragment(
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message_id=reader.read_uint32(),
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fragment_count=reader.read_uint8(),
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fragment_id=reader.read_uint8(),
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mtu=reader.read_uint16(),
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)
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if frag.is_compressed:
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frag.decompressed_size = reader.read_uint32()
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frag.crc = reader.read_uint32()
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frag.payload = bz2.decompress(reader.read())
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else:
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frag.payload = reader.read()
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return frag
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