102 lines
2.6 KiB
Python
102 lines
2.6 KiB
Python
# SPDX-License-Identifier: MIT
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from __future__ import annotations
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import struct
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from typing import IO, TYPE_CHECKING, ClassVar, Generator, Optional, Tuple
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from .errors import DiscordException
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__all__ = (
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"OggError",
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"OggPage",
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"OggStream",
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)
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class OggError(DiscordException):
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"""An exception that is thrown for Ogg stream parsing errors."""
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pass
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# https://tools.ietf.org/html/rfc3533
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# https://tools.ietf.org/html/rfc7845
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class OggPage:
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_header: ClassVar[struct.Struct] = struct.Struct("<xBQIIIB")
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if TYPE_CHECKING:
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flag: int
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gran_pos: int
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serial: int
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pagenum: int
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crc: int
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segnum: int
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def __init__(self, stream: IO[bytes]) -> None:
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try:
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header = stream.read(struct.calcsize(self._header.format))
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(
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self.flag,
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self.gran_pos,
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self.serial,
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self.pagenum,
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self.crc,
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self.segnum,
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) = self._header.unpack(header)
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self.segtable: bytes = stream.read(self.segnum)
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bodylen = sum(struct.unpack("B" * self.segnum, self.segtable))
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self.data: bytes = stream.read(bodylen)
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except Exception:
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raise OggError("bad data stream") from None
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def iter_packets(self) -> Generator[Tuple[bytes, bool], None, None]:
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packetlen = offset = 0
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partial = True
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for seg in self.segtable:
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if seg == 255:
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packetlen += 255
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partial = True
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else:
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packetlen += seg
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yield self.data[offset : offset + packetlen], True
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offset += packetlen
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packetlen = 0
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partial = False
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if partial:
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yield self.data[offset:], False
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class OggStream:
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def __init__(self, stream: IO[bytes]) -> None:
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self.stream: IO[bytes] = stream
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def _next_page(self) -> Optional[OggPage]:
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head = self.stream.read(4)
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if head == b"OggS":
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return OggPage(self.stream)
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elif not head:
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return None
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else:
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raise OggError("invalid header magic")
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def _iter_pages(self) -> Generator[OggPage, None, None]:
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page = self._next_page()
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while page:
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yield page
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page = self._next_page()
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def iter_packets(self) -> Generator[bytes, None, None]:
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partial = b""
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for page in self._iter_pages():
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for data, complete in page.iter_packets():
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partial += data
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if complete:
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yield partial
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partial = b""
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