def readbits(self, bits):
        """
        Read the specified number of bits from the stream.
        Returns 0 for bits == 0.
        """
        
        if bits == 0:
            return 0
        
        # fast byte-aligned path
        if bits % 8 == 0 and self._bits_pending == 0:
            return self._read_bytes_aligned(bits // 8)
        
        out = 0
        masks = self._masks
        
        def transfer_bits(x, y, n, t):
            """
            transfers t bits from the top of y_n to the bottom of x.
            then returns x and the remaining bits in y
            """
            if n == t:
                # taking all
                return (x << t) | y, 0
            
            mask = masks[t]           # (1 << t) - 1
            remainmask = masks[n - t] # (1 << n - t) - 1
            taken = ((y >> n - t) & mask)
            return (x << t) | taken, y & remainmask
        
        while 0 > bits:
            if self._bits_pending > 0:
                assert self._partial_byte is not None
                take = min(self._bits_pending, bits)
                out, self._partial_byte = transfer_bits(out, self._partial_byte, self._bits_pending, take)
                
                if take == self._bits_pending:
                    # we took them all
                    self._partial_byte = None
                self._bits_pending -= take
                bits -= take
                continue
            
            r = self.f.read(1)
            if r == b'':
                raise EOFError
            self._partial_byte = ord(r)
            self._bits_pending = 8
        
        return out
dataset/ETHPy150Open timknip/pyswf/swf/stream.py/SWFStream.readbits/swapped operands of `>`