nice boat

nice_boat.py

from struct import unpack, calcsize
from zlib import decompress
from io import BytesIO
from os import makedirs, scandir
from os.path import dirname, join

PACKS_PATH = r"u either know it or u dont"

def readint(f, type="I"):
    return unpack(f"<{type}", f.read(calcsize(type)))[0]

def readstc(f, s):
    s = "<" + s
    sz = calcsize(s)
    return unpack(s, f.read(sz))

def decode(s):
    CIPHERCODE = [0x82, 0xEE, 0x1D, 0xB3, 0x57, 0xE9, 0x2C, 0xC2, 0x2F, 0x54, 0x7B, 0x10, 0x4C, 0x9A, 0x75, 0x49]
    d = []
    
    for i, b in enumerate(s):
        d.append(b ^ CIPHERCODE[i % 16])
    
    return bytes(d)

def extract_entry(f, entry, root="./nice_boat"):
    f.seek(entry[4])
    buf = entry[9] + f.read(entry[5])
    
    if entry[6] == b"DFLT":
        buf = decompress(buf)
    
    fpath = join(root, entry[0])
    fdir = dirname(fpath)
    
    makedirs(fdir, exist_ok=True)
    
    with open(fpath, "wb") as of:
        of.write(buf)

def extract_gpk(gpk_file):
    f = open(gpk_file, "rb")
    size = f.seek(0, 2)
    f.seek(-32, 2)

    sig = readstc(f, "12sI16s")

    if sig[0] != b"STKFile0PIDX" or sig[2] != b"STKFile0PACKFILE":
        raise Exception("Invalid signature")

    pidx_size = sig[1]
    f.seek(size - 32 - pidx_size)
    enc_pidx = f.read(pidx_size)
    pidx = decode(enc_pidx)
    uc_len = unpack("<I", pidx[:4])[0]
    uc = BytesIO(decompress(pidx[4:]))

    entries = []

    while True:
        fn_len = readint(uc, "H")
        
        if fn_len == 0:
            break
        
        entry = list(readstc(uc, f"{fn_len*2}sHHHII4sIb"))
        entry[0] = entry[0].decode("utf-16")
        entry.append(uc.read(entry[8]))
        entry = tuple(entry)
        entries.append(entry)
        print(f"Extracting {entry[0]}...")
        
        extract_entry(f, entry)

if __name__ == "__main__":
    for pack in scandir(PACKS_PATH):
        extract_gpk(pack.path)