Grimrock

Posted: **Mon Apr 30, 2012 4:08 pm**

Moved to modding.

Daniel.

Posted: **Mon Apr 30, 2012 8:22 pm**

Dej wrote:
x000000 47 52 49 4d 04 00 00 00 81 c2 0e 00 78 9c ec 7d 'GRIM........x...'

I'm assuming that the 04 is a version tag or something similar.
The 04 after the "GRIM" keyword is in fact the size of the segment data. That size is encoded as a 32-bit word in little-endian and will be the same on all save files: 04 00 00 00.

The segment data is therefore the next 32-bit word (at offset 8). It is also a size, and also little-endian. It is the size of the uncompressed zlib data. In the example above 81 c2 0e 00 --> 0x0EC281 = 967'297 bytes.

Following that is the zlib data. The first 16-bit word (offset 12) is the zlib data header. It will not change from one save file to the other: always 0x789C (which corresponds to a standard zlib compression). Following that is the compressed data.

d'oh

I had gotten as far as "segment data size" but somehow I'd ... oh, geeze. I compared it to the size of the file, which it wasn't, and didn't realize that it might be the size of something contained within the file.

Posted: **Mon Apr 30, 2012 8:56 pm**

Hi,

That pattern (TAG word on 4 Bytes + SIZE as a 32-bit integer, little-endian) is typical in the uncompressed data. That's how I deduced that the 04 00 00 00 must also be a size.

Pierre

Grimrock

It's not a DM game without people attacking the save files

Re: It's not a DM game without people attacking the save fil

Re: It's not a DM game without people attacking the save fil

Re: It's not a DM game without people attacking the save fil