lightweight Brain Vision data reader

vhdr.py

import StringIO
import ConfigParser

import numpy as np

class VHDR(object):
    """
    Brain Vision file.

    """

    def __init__(self, filename):
        self.filename = filename

        # read file
        with open(self.filename, 'r') as fd:
            self.srclines = fd.readlines()

        # config parser expects each section to have header
        # but vhdr has some decorative information at the beginning
        while not self.srclines[0].startswith('['):
            self.srclines.pop(0)

        self.sio = StringIO.StringIO()
        self.sio.write('\n'.join(self.srclines))
        self.sio.seek(0)

        self.cp = ConfigParser.ConfigParser()
        self.cp.readfp(self.sio)

        for opt in self.cp.options('Common Infos'):
            setattr(self, opt, self.cp.get('Common Infos', opt))

        self.binaryformat = self.cp.get('Binary Infos', 'BinaryFormat')

        self.labels = [self.cp.get('Channel Infos', o).split(',')[0] 
                for o in self.cp.options('Channel Infos')]

        self.nchan = int(self.numberofchannels)

    def read_data(self, mmap=True, dt='float32', mode='r'):
        """
        VHDR stores data in channel contiguous way such that reading disparate pieces
        in time is fast, when using memmap.
        """

        if mmap:
            ary = np.memmap(self.datafile, dt, mode)
        else:
            ary = np.fromfile(self.datafile, dt)
        return ary.reshape((-1, self.nchan)).T