Joying Allapp.pkg extractor

extract-allapppkg.py

#!/usr/bin/env python
# Copyright (C) 2020 Yuki MIZUNO
# SPDX-License-Identifier: GPL-3.0-only

from __future__ import print_function, unicode_literals
from argparse import ArgumentParser, FileType
from os import makedirs
from os.path import exists, join
from struct import unpack, calcsize


def unpack_input(fmt, f):
    size = calcsize(fmt)
    data = f.read(size)
    return unpack(fmt, data)


def parse_args():
    parser = ArgumentParser()
    parser.add_argument(
        '-i', '--input', help='input file', type=FileType('rb'), required=True)
    parser.add_argument(
        '-o', '--output', help='output directory', default='./out')
    return parser.parse_args()


def main():
    args = parse_args()
    if not exists(args.output):
        makedirs(args.output)

    [count, start] = unpack_input("12xI48xI", args.input)
    args.input.seek(start, 0)

    for _ in range(count):
        [entry_size, name_size] = unpack_input("4xI28xI", args.input)
        name = args.input.read(name_size)[:-1].decode()

        with open(join(args.output, name), 'wb') as f:
            f.write(args.input.read(entry_size))

        padding = 4 - (args.input.tell() % 4)
        args.input.seek(padding, 1)


if __name__ == '__main__':
    main()