State of Decay 2 saved game tools

A set of tools for working with save files from the game State of Decay 2.

Included so far are:

• decomp - a script to decompress a save file.
• recomp - a script to recompress a decompressed save file.

Prerequisites

1. If you are not comfortable with a hex editor then these aren't the tools for you. Also, they are command-line scripts, not point and click.
2. You have to be willing to install the Erlang programming language. Details may be found below.

Installing Erlang

There is a Windows installer on the Erlang downloads page. I'm using Erlang/OTP 24, but it's likely that the scripts will work with other versions.

The installer doesn't add the Erlang bin directory to your path, so please do that yourself; otherwise, the scripts won't run.

Running the scripts

Before you run anything, first backup your save files! The scripts won't ask you if you want to overwrite an existing file.

On Windows

The scripts must be run using the escript executable that comes with the Erlang installation. This will work only if the Erlang bin directory is in your path. Run them like this:

escript decomp <compressed-filename> <decompressed-filename>

to decompress a save file. For example,

escript decomp SaveGame0.sav save0

or:

escript recomp <uncompressed-filename> <compressed-filename>

to recompress a save file that you previously decompressed. For example,

escript recomp save0 SaveGame0.sav

On Linux

The scripts start with a shebang for escript, so you just need to do a chmod u+x to make them executable. After that you can run them as:

decomp <compressed-filename> <decompressed-filename>

to decompress a save file. For example,

decomp SaveGame0.sav save0

or:

recomp <uncompressed-filename> <compressed-filename>

to recompress a save file that you previously decompressed. For example,

recomp save0 SaveGame0.sav

Why Erlang?

I wrote this code in Erlang for two main reasons:

1. Erlang is a really good language for manipulating data at the bits-and-bytes level.
2. My Erlang skills were getting rusty, and I wanted to stretch them a bit.

If you are interested in learning to program in Erlang there is documentation at the Erlang site, but I would recommend starting with the excellent Learn you some Erlang.

If any Erlang experts out there are horrified by my code, and my violation of all sane Erlang idioms, I would welcome critiques!

Licence

The code is licensed under GPL-2.0-or-later. Please see the COPYING file for details.