read_subs.py

from __future__ import print_function
import sys
import struct

if __name__ == '__main__':
    if len(sys.argv) < 3:
        print("USAGE: %s <FILENAME> <OFFSET>\n")
        exit(0)

    read_uchar = struct.Struct("<B").unpack
    write_obj = getattr(sys.stdout, "buffer", sys.stdout)
    with open(sys.argv[1], "rb") as fp:
        fp.seek(int(sys.argv[2]))
        try:
            while True:
                block_len = read_uchar(fp.read(1))[0]
                if not block_len: break
                data = fp.read(block_len)
                if len(data) != block_len:
                    print("Corrupt block. File ended to early.")
                    break
                write_obj.write(data)
        except struct.error:
            print("Corrupt block. File ended to early.")