extract.py

"""Extract every file from the data track, decompressing the RNC ones.

    python tools/extract.py <track1.iso> <outdir>

Writes the raw file next to a `.raw` sibling when it was compressed, so both
the on-disc bytes and the unpacked payload are available for inspection.
"""
import os, sys
sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
from isofs import Iso
import rnc

def main(iso_path, outdir):
    iso = Iso(iso_path)
    os.makedirs(outdir, exist_ok=True)
    for e in iso.walk():
        if e.is_dir:
            os.makedirs(os.path.join(outdir, e.path.strip('/')), exist_ok=True)
            continue
        name = e.path.strip('/').replace(';1', '')
        dst = os.path.join(outdir, name)
        os.makedirs(os.path.dirname(dst) or '.', exist_ok=True)
        blob = iso.read(e)
        open(dst, 'wb').write(blob)
        if blob[:3] == b'RNC':
            i = rnc.info(blob)
            try:
                out = rnc.unpack(blob)
                open(dst + '.bin', 'wb').write(out)
                print('%-16s %7d -> %7d  ratio %5.1f%%  chunks %d leeway %d' %
                      (name, e.size, len(out), 100.0 * e.size / len(out),
                       i['chunks'], i['leeway']))
            except Exception as ex:
                print('%-16s %7d  RNC FAILED: %s' % (name, e.size, ex))
        else:
            print('%-16s %7d  (stored)' % (name, e.size))

if __name__ == '__main__':
    main(sys.argv[1], sys.argv[2])