Auto Modellista BIN Extractor

am_extract.py

import os
import sys
import struct

def wu08(value):
    return struct.pack("<B", value)

def int32_read(buf, offset):
    return struct.unpack("<i", buf[offset:offset+4])[0]
    
def pzz_decompress(b): # by infval # https://github.com/infval/pzzcompressor_jojo/blob/master/pzz_comp_jojo.py
    bout = bytearray()
    size_b = len(b) // 2 * 2

    cb = 0  # Control bytes
    cb_bit = -1
    i = 0
    while i < size_b:
        if cb_bit < 0:
            cb  = b[i + 0]
            cb |= b[i + 1] << 8
            cb_bit = 15
            i += 2
            continue

        compress_flag = cb & (1 << cb_bit)
        cb_bit -= 1

        if compress_flag:
            c  = b[i + 0]
            c |= b[i + 1] << 8
            offset = (c & 0x7FF) * 2
            if offset == 0:
                break # End of the compressed data
            count = (c >> 11) * 2
            if count == 0:
                i += 2
                c  = b[i + 0]
                c |= b[i + 1] << 8
                count = c * 2

            index = len(bout) - offset
            for j in range(count):
                bout.append(bout[index + j])
        else:
            bout.extend(b[i: i + 2])
        i += 2

    return bout


def get_ext(file):
    test = int32_read(file, 0x4)
    if test == 4: return "amo"
    test = int32_read(file, 0x0)
    if test == 843925844: return "tm2"
    else: return "bin"


filepath = sys.argv[1]

with open(filepath, "rb") as input_file:
    buf = input_file.read()
    funny = pzz_decompress(buf)
    filename = os.path.basename(filepath)[:-4]
    
    working = True
    read_offset = 0x0 
    os.mkdir(filename)
    index = 0
    while working:
        file_offset = int32_read(funny, read_offset)
        
        if file_offset == -1:
            break
        
        file_end = int32_read(funny, read_offset+0x4)
        
        if file_end == -1: 
            file_end = len(funny)
            
        
        file = funny[file_offset:file_end]
        type = get_ext(file)
        
        with open(f"{filename}/file{index:04}_{hex(file_offset)}.{type}", "wb") as out_file:
            for byte in bytearray(file):
                aah = wu08(byte)
                out_file.write(aah)
        
        read_offset += 0x4
        index += 1
        if file_end == -1: working = False
    
    print(int32_read(funny, 0x0))