util.py 文件源码

def filter(self, bytes, end=True, bfinal=False):
        if self._deflater is None:
            self._deflater = _Deflater(self._window_bits)

        if bfinal:
            result = self._deflater.compress_and_finish(bytes)
            # Add a padding block with BFINAL = 0 and BTYPE = 0.
            result = result + chr(0)
            self._deflater = None
            return result

        result = self._deflater.compress_and_flush(bytes)
        if end:
            # Strip last 4 octets which is LEN and NLEN field of a
            # non-compressed block added for Z_SYNC_FLUSH.
            result = result[:-4]

        if self._no_context_takeover and end:
            self._deflater = None

        return result