DPK

Revision as of 19:29, 25 June 2023

A .dpk file is a simple archive format without compression. The format appears to be proprietary and specific to the Bunny Pro. Das2 visual novel software for Windows.

Specification

The format comprises a header and payload.

The header includes the magic bytes "PA" followed by the number of entries (short) and total file size (int). Each file entry in the header is then designated by a null-padded string of 16 characters (ASCII) and the length of the file (int)

Files in the payload are stored in the order in which the entry appears, and can be extracted by reading the number of bytes corresponding to the length of the file.

Source

The following source can be used to extract .dpk files using Python.

import struct
import argparse
import os

header_format = '2shi'
header_size = struct.calcsize(header_format)

entry_format = '16si'
entry_size = struct.calcsize(entry_format)

def unpack(fileName):
	BASE_NAME = os.path.splitext(os.path.basename(fileName))[0]

	os.mkdir(BASE_NAME)

	with open(fileName, 'rb') as f:
		[magic_bytes, file_count, package_size] = struct.unpack(header_format, f.read(header_size))

		assert magic_bytes == b'PA'
		assert file_count > 0
		assert package_size > 0

		FILES = []

		for i in range(0, file_count, 1):
			[file_name, file_size] = struct.unpack(entry_format, f.read(entry_size))
			
			FILES.append([
				file_name.decode("ascii").rstrip('\x00'),
				file_size
			])
		
		for file_name, file_size in FILES:
			file_data = bytearray(f.read(file_size))

			with open(os.path.join(BASE_NAME, file_name), 'wb') as new_file:
				new_file.write(file_data)

if __name__ == '__main__':
	parser = argparse.ArgumentParser(
                    prog = 'dpk Unpacker',
                    description = 'Unpacks .dpk packages')
	parser.add_argument('INPUT_FILE')
	args = parser.parse_args()
	
	unpack(args.INPUT_FILE)

Sample files

• Corsage -→ ...Disc 1.iso → WAV.DPK