richmondx/juepak2

Unreal Engine 4 PAK Archiver in pure java

JUEPAK II

JuepakII [ʤuːpæk] (Java Unreal Engine PAK-archiver) is an Unreal Engine 4 *.PAK archiver, written in pure java8. It can browse PAK-archives, extract assets from such archives, and make new archives from existing assets. It fully supports both compressed and encrypted archives. It is completely compatible with UE4.20 and below.

Coding standard

A coding standard within this project might be a bit confusing, but let me explain clearly why is it as it is. Two independent coding standards are used in this project:

• Epic Games coding standard is used in some UE4-related classes to replicate UE4 functionality. Since Unreal Engine and it's packing mechanism is continuously developing, we need a stable and robust way to import upstream changes. That also means that you can see F-notation for structures, usage of checkf(), TEXT() and some other macros, parts of ported core-UE classes and, of course, old but gold sizeof() with some limitations. It is very important to understand that I did not set myself the goal of completely replicate Epic Games's code (for example, below the facade of ported FAES is actually a plain java Cipher), but instead I tried to make the porting of the Epic company code simple and convenient.
• TODO: Write (plain java coding standard).

Pak archive structure

• TODO: Write

Compression

• TODO: Write

Encryption

You may want to Encrypt your PAK archives (see 'Signing and Encryption'), fortunately, juepak II can process encrypted PAK-files as well. Of course, you will need the right key, otherwise the archiver can not operate.

Approach

UE4 uses reference implementation of AES/CBC to encrypt and decrypt data. The key is provided to the packing/unpacking code by FCoreDelegates::GetPakEncryptionKeyDelegate() which is provided by ... TODO: FINISH

API

• TODO: write

Benchmarks

• TODO: Write