label.py

#!/usr/bin/env python

"""
Sample of parsing PDS Labels into an OrderedDict
"""

from collections import OrderedDict


def parse_label(pds_file):
    """
    Parses a PDS Label from a file, returns an ordered dict
    """
    label = OrderedDict()
    in_block = None
    with open(pds_file) as f:
        for line in f.readlines():
            line = line.rstrip()  # strip off the ^M and any trailing garbage
            if '=' in line:
                key, value = line.split('=')
                key = key.strip()
                value = value.strip()
                if key in ['OBJECT', 'GROUP']:
                    in_block = value
                    label[value] = OrderedDict([('_type', key)])
                elif key in ['END_OBJECT', 'END_GROUP']:
                    in_block = None
                else:
                    if in_block:
                        label[in_block][key] = value
                    else:
                        label[key] = value

            if line.strip() == 'END':
                break

    return label


def main(pds_files):
    import json
    for pds_file in pds_files:
        r = parse_label(pds_file)
        print(json.dumps(r, indent=4))


if __name__ == '__main__':
    pds_files = [
        '/home/godber/Workspace/test_data/I18584006BTR.IMG',
        '/home/godber/Workspace/test_data/MER/1P345688456EFFB0EJP2363L2C1.IMG',
    ]
    main(pds_files)