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Efficiently reading structured binary files using numpy's fromfile method

nev_packet = pylab.dtype([
    ('nstx', 'h'),
    ('npkt_id', 'h'),
    ('npkt_data_size', 'h'),
    ('timestamp', 'Q'),
    ('eventid', 'h'),
    ('nttl', 'H'),
    ('ncrc', 'h'),
    ('ndummy1', 'h'),
    ('ndummy2', 'h'),
    ('dnExtra', '8i'),
    ('eventstring', '128c')
  ])
  data = pylab.fromfile(fin, dtype=nev_packet, count=-1)

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