ROM Hack A question about bin compressions

[matthewn4444]

Does anyone know how to extract/decompress bin files that has LZ77 compression? (I'm trying to extract sc.bin from Shakugan no Shana DS). I also tried GBADecmpDemo.exe, but I don't know how to use it. Can Anyone help?

 

[FAST6191]

Assuming it is normal LZ compression I tend to go with the demo tool from
http://gbadev.org/tools.php?showinfo=56

If it is not normal LZ (rare but common enough to mention) then you will likely have to figure it out the compression and reimplement it (the tool above should serve as a good base). http://nocash.emubase.de/gbatek.htm also has some decent info on compression.

Also you might like to take a look around http://www.romhacking.net/ I have not kept up with the latest LZ compression but some of the tools are pretty nice there.

 

[matthewn4444]

Sorry and I'm still a noob, but how do these programs work?

 

[DarthNemesis]

Here you go: http://www.sendspace.com/file/ujq9w1

 

[matthewn4444]

Thank you and was this extractor just for this game?

 

[undercarris]

i have a question thats nothing to do with this xD........ .... is there any homebrew that reads games that are inside a ZIP file or a RAR file XD? this would be very usefull to minimize the games zize

xD

 

[FAST6191]

The tool is just a command line app and is fairly dumb: that app only decompresses the entire file meaning it is generally a good idea to get what you need before you start. Usage is on the link and in the download.

As for compressed roms. Some GBA stuff can do it as files are transferred to different memory sections and there is DSCompress that can do zip and gzip.
90% of the space saved though is also saved by trimming the rom and the extra time and effort needed generally does not make for a good reason to compress roms.
http://voidptr.org/?page_id=25

 

[DarthNemesis]

Thank you and was this extractor just for this game?

Yes, just for this game. Well, the unpacking algorithm itself is common, but file formats vary widely between games. In this case I didn't see any header information, so I just used patterns (all files start at an offset that's a multiple of 256) to find the next file.