fixing broken .Z files?

Jim Battle wrote: .Z is the output of compress, which doesn't inherently seperate data by blocks (if it did, you could decompress until bad data was found, then skip to the next block and start over). It does, however, support a complete flush and rebuild of the dictionary with code 257, so if you had bad data in a .Z file, you could attempt to skip over it by searching for the next 257 code, then start over. The drawback to this is, what if some of the mangled data inadvertently inserts a 257 code? :-) I don't have time to burn, so I won't code this for you, but anyone versed in LZW/LZ78 compression schemes and C could probably write a .Z file salvager (especially since the source code for compress is freely available). Any compressed format that compresses in a stream (ie where the data is not arbitrarily blocked or otherwise seperated) is going to have this problem -- anything corrupted will boffo the rest of the file after that point. Programs like pkzipfix, etc. simply rebuild the archive by skipping the file with the bad data. If you want real repairs, you need an archiver that generates parity information and tacks it onto the archive. WinRAR does this, as does WinRK and a few others. -- Jim Leonard (trixter at oldskool.org) http://www.oldskool.org/ Want to help an ambitious games project? http://www.mobygames.com/ Or check out some trippy MindCandy at http://www.mindcandydvd.com/