File compression?

[IBBoard]

I asked this in an email nearly a month ago now and I got the automated response but never saw a human's reply. Time to try my chances on the Lone Wolf forum

I've been looking at the .ab file format at a low level and it appears to be a quite simple archive format. The main thing I don't know but am interested in at the moment is what the compression format is for the files. Relic's SGA files in Dawn of War just use deflated/zlibed, but the .ab files don't seem to contain be deflated/gzipped/bzipped (or at least not that I've been able to work with so far).

Can anyone enlighten me on the compression algorithm used?

Thanks,

IBBoard