file_structure.py 文件源码

def _iter_files(self, offset: int, data_length: int) -> Iterable[Tuple[BinaryIO, int, int]]:
        if offset < 0 or offset + data_length > self._download_info.total_size:
            raise IndexError('Data position out of range')

        # Find rightmost file which start offset less than or equal to `offset`
        index = bisect_right(self._offsets, offset) - 1

        while data_length != 0:
            file_start_offset = self._offsets[index]
            file_end_offset = self._offsets[index + 1]
            file_pos = offset - file_start_offset
            bytes_to_operate = min(file_end_offset - offset, data_length)

            descriptor = self._descriptors[index]
            yield descriptor, file_pos, bytes_to_operate

            offset += bytes_to_operate
            data_length -= bytes_to_operate
            index += 1