neuralynxio.py 文件源码

def __mmap_ncs_packet_headers(self, filename):
        """
        Memory map of the Neuralynx .ncs file optimized for extraction of
        data packet headers
        Reading standard dtype improves speed, but timestamps need to be
        reconstructed
        """
        filesize = getsize(self.sessiondir + sep + filename)  # in byte
        if filesize > 16384:
            data = np.memmap(self.sessiondir + sep + filename,
                             dtype='<u4',
                             shape=((filesize - 16384) / 4 / 261, 261),
                             mode='r', offset=16384)

            ts = data[:, 0:2]
            multi = np.repeat(np.array([1, 2 ** 32], ndmin=2), len(data),
                              axis=0)
            timestamps = np.sum(ts * multi, axis=1)
            # timestamps = data[:,0] + (data[:,1] *2**32)
            header_u4 = data[:, 2:5]

            return timestamps, header_u4
        else:
            return None