zipfile.py 文件源码

def _update_crc(self, newdata, eof):
        # Update the CRC using the given data.
        if self._expected_crc is None:
            # No need to compute the CRC if we don't have a reference value
            return
        self._running_crc = crc32(newdata, self._running_crc) & 0xffffffff
        # Check the CRC if we're at the end of the file
        if eof and self._running_crc != self._expected_crc:
            raise BadZipfile("Bad CRC-32 for file %r" % self.name)