114 lines
3.6 KiB
Python
114 lines
3.6 KiB
Python
"""
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The MIT License (MIT)
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Copyright (c) 2015-present Rapptz
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Permission is hereby granted, free of charge, to any person obtaining a
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copy of this software and associated documentation files (the "Software"),
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to deal in the Software without restriction, including without limitation
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the rights to use, copy, modify, merge, publish, distribute, sublicense,
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and/or sell copies of the Software, and to permit persons to whom the
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Software is furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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DEALINGS IN THE SOFTWARE.
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"""
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from __future__ import annotations
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import struct
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from typing import TYPE_CHECKING, ClassVar, IO, Generator, Tuple, Optional
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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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self.flag, self.gran_pos, self.serial, \
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self.pagenum, self.crc, self.segnum = 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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