aPACK compression

[AcarX]

Hi everyone. So I built this map viewer for an old MMORPG called Archlord. I would like to add an editing feature to it. The map files are compressed and currently I'm using the binary code I got from client to uncompress them. I was told by lastfun that it's compressed using aPACK. However I cannot seem to find a matching implementation of this compression algorithm. The one I've got from the official website is working only for a small part of the file. I'll leave a compressed and uncompressed version of a sample file in the attachments.

If you know of an implementation which works with the files I have or if you know how the algorithm works I would appreciate your help.View attachment map_sample.rar

 

[lastfun]

hi)
R345,438_uncompressed.dff - completely and correctly unpacked?

 

[AcarX]

Hey. Yes I've rendered the contents and it looks correct.

 

[lastfun]

bro) i forgot that it was about a year ago, but this (*.dff) is not aplib ))) -> header 0x16, 0xE1
or i forgot something really)
p/s/ need debug client and see....

 

[AcarX]

All good I'm not in a rush as you might've noticed

I couldn't find it but perhaps it's possible that compress function is also somewhere in the client?

 

[lastfun]

...possible that compress function is also somewhere in the client?

looking in the client at now time)

 

[AcarX]

Oh my god I actually found the function!!

I searched for a similar signature with original aP_pack from the dll and managed to find it after a few hours. It starts at "alefclient.exe + 0x4526F9"(at least in my version). I've tested it and it works perfectly.

However I got no clue how to extract it as bin code since it's calling a few other functions.

-------------

I just found this version of the library:
ftp://mindcandydvd.com/pub/ANORMAL ...xecutable Tools Pack/tools/aplib.019-jibz/vc/

It produces a completely different packed file(same size) but somehow when unpacked it gives the same output. I will share the results once I write a complete unpacker/packer and test it.