Crimsonland (Steam) Pak Format

clpak.py

import os
import struct


"""

Crimsonland (Steam) pak file format

Header format:
50 40 4B 00 56 31 31 00   ("PAK" NUL "V11" NUL)
int32 index offset     (eg: 28679361)
int32 end index offset (eg: 28885444)

Index Format:
int32 number of indexes?

Index_File format:
null terminated string
int32 absolute offset of file
int32 file length
unknown maybe always (?) equal to: FF 26 E2 50 20 00 00 00

"""


class ClPak(object):
    def __init__(self, filename):
        self.file = open(filename, 'rb')

    def read_header(self):
        self.file.seek(0)
        bytes = self.file.read(16)

        (magic_1, magic_2, index_start_offset, index_end_offset) = struct.unpack('3sx3sxii', bytes)

        if magic_1 != 'PAK' or magic_2 != 'V11':
            raise Exception('Unknown file format')

        return index_start_offset, index_end_offset


    def read_index(self):
        start_offset, end_offset = self.read_header()

        self.file.seek(start_offset)
        bytes = self.file.read(end_offset - start_offset)

        # index_size = struct.unpack('i', bytes[:4])

        return self.read_index_file_details(bytes[4:])


    def read_index_file_details(self, bytes):

        details = {'name': '', 'offset': 0, 'length': 0, 'unknown': ''}

        sequence = iter(bytes)

        for char in sequence:
            if char != chr(0):
                details['name'] += char
            else:
                offset_bytes = sequence.next() + sequence.next() + sequence.next() + sequence.next()
                length_bytes = sequence.next() + sequence.next() + sequence.next() + sequence.next()

                (details['offset'],) = struct.unpack('i', offset_bytes)
                (details['length'],) = struct.unpack('i', length_bytes)

                for x in range(0, 8):
                    details['unknown'] += sequence.next()

                yield details

                details = {'name': '', 'offset': 0, 'length': 0, 'unknown': ''}


    def dump_file(self, details, base_directory):
        dest_filename = base_directory + '/' + details['name']

        if not os.path.exists(os.path.dirname(dest_filename)):
            os.makedirs(os.path.dirname(dest_filename))

        with open(dest_filename, 'wb') as dest:
            self.file.seek(details['offset'])
            dest.write(self.file.read(details['length']))


if __name__ == '__main__':
    cl_pak = ClPak(r'D:\Steam\steamapps\common\Crimsonland\data.pak')
    for file_details in cl_pak.read_index():
        print file_details
        cl_pak.dump_file(file_details, 'd:/clpak_files')