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atom0s, posted Sun Dec 28, 2014 8:58 am (2328)

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grimarz - Grim Dawn Database File Extractor (.arz)

Here is my project / extractor for the .arz files. This will fully extract any .arz database file for Grim Dawn. (Currently only one exists.)
This project is open source released under the GPL v3 license.

Project Home: https://gitlab.com/atom0s/grimarz
Bug Reports: https://gitlab.com/atom0s/grimarz/issues
Pull Requests: https://gitlab.com/atom0s/grimarz/merge_requests

.ARZ File Header

Code:

struct GRIMDAWN_ARZ_V3_HEADER
{
    unsigned int Unknown; // Assumed version check.
    unsigned int RecordTableStart;
    unsigned int RecordTableSize;
    unsigned int RecordTableEntryCount;
    unsigned int StringTableStart;
    unsigned int StringTableSize;
};

The first unknown in this structure seems to be some sort of file check to ensure the file is a proper .arz file. However I did not spend much time on it trying to figure it out. The data for it looks like this:

Code:

  v4 = *(_DWORD *)a1;
  v5 = (unsigned __int16)*(_DWORD *)a1;
  v3 = a1   4;
  *(_DWORD *)a3 = v4;
  if ( v5   {
    result = 0;
  }

String Table Format

Code:

0x00000000    unsigned int    Number Of Strings In Table
    ->        unsigned int    String Length
    ->        char[]          String
    ->        unsigned int    String Length
    ->        char[]          String

... etc until number of strings is met.

Important: Strings in the table ARE NOT null terminated. They are fixed size strings based on the unsigned int before the start of the string!

Record Table Format

Code:

0x00000000    unsigned int    File Path String Id
0x00000004    unsigned int    String Length
0x00000008    char[]          String (Record Type) [String is not null terminated!]
0x000000??    unsigned int    Record Data Position
0x000000??    unsigned int    Record Data Length (Compressed)
0x000000??    unsigned int    Record Data Length (Decompressed)
0x000000??    unsigned int64  Record File FILETIME

Record Data Format
Before you can read the record data, you must decompress it. Grim Dawn uses LZ4 decompression.
If you need a working library that is tested to work with the Grim Dawn files, you can use:
- C/C : http://code.google.com/p/lz4/
- C# : https://lz4net.codeplex.com/

To decompress the data, use the compress and decompressed sizes known from the record table entry for this data object.
Once decompressed, the format is:

Code:

0x00000000    unsigned short  Data Type [See Below]
0x00000002    unsigned short  Value Count
0x00000004    unsigned int    String Key Id
0x00000008    unsigned int    Value [To be read as int/float/bool as needed.]

The data type can be one of the following:

Code:

 -> 0x0000 == Int32 Value
 -> 0x0001 == Float Value
 -> 0x0002 == String Value [Value will be index inside of string table of the string.]
 -> 0x0003 == Boolean Value

The value is always 4 bytes long regardless of the type read. If the value is a string, it is the index in the string table of the string. Remember, strings are not read based on index / position. So you need to dump the string table (or walk it manually each time) first into a container and index the container for the string being requested.

The rest of the file is 4 DWORDs at the end. I am uncertain what they do. I know where the game references them while loading the database but they are not used in any type of compares or checks. They are simply loaded and moved to a buffer. Afterward they never seem to be touched.

Special thanks to Shalie for his/her notes on some parts of the file I was stuck with.

atom0s, posted Sat Feb 13, 2016 7:30 am (11382)

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I have moved this project to Gitlab as Github has been bought over by corporate greed.
https://gitlab.com/atom0s/grimarz

Dank Rafft, posted Sun Feb 14, 2016 4:13 pm (11418)

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Thanks for that tool. Is it somehow possible to also compile a database.arz with it?

atom0s, posted Mon Feb 15, 2016 5:53 am (11431)

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Dank Rafft wrote:

Thanks for that tool. Is it somehow possible to also compile a database.arz with it?

I never got around to implementing a recompiler for it. I lost interest in the game in general since its fairly boring in my opinion.

Dank Rafft, posted Mon Feb 15, 2016 7:13 pm (11442)

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atom0s wrote:

Dank Rafft wrote:

Thanks for that tool. Is it somehow possible to also compile a database.arz with it?

I never got around to implementing a recompiler for it. I lost interest in the game in general since its fairly boring in my opinion.

That's really too bad. Thanks for your quick reply, though.