Simple bdox reader

bdox.py

import sys
import numpy as np


def get_token(f):
    """
    returns a tuple with 4 elements:
    0: payload id
    1: payload dtype string
    2: payload number of elements
    3: payload itself

    returns None if no token was found / EOF
    """

    tag = np.dtype([('pl_id', '<u8'),
                    ('pl_type', 'S8'),
                    ('pl_len', '<u8')])

    x1 = np.fromfile(f, dtype=tag, count=1)  # read the data into numpy

    if not x1:
        return None
    else:
        pl_id = x1['pl_id'][0]
        pl_type = x1['pl_type'][0]
        pl_len = x1['pl_len'][0]
        pl = np.fromfile(f,
                         dtype=pl_type,
                         count=pl_len)  # read the data into numpy
        return(pl_id, pl_type, pl_len, pl)


def main(args=sys.argv[1:]):
    """ Simple reader for .bdox files
    """

    filename = sys.argv[1]
    print(filename)
    with open(filename, "rb") as f:
        d1 = np.dtype([('magic', 'S6'),
                       ('end', 'S2')])

        x = np.fromfile(f, dtype=d1, count=1)  # read the data into numpy
        print(x['magic'][0])
        print(x['end'][0])

        while (f != []):
            token = get_token(f)
            if token is None:
                break
            print(token[0], token[1], token[2])
            for i, j in enumerate(token[3]):
                print(i, j)


if __name__ == '__main__':
    sys.exit(main(sys.argv[1:]))