Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!samsung!zaphod.mps.ohio-state.edu!van-bc!ubc-cs!alberta!ccu!shad04
From: shad04@ccu.umanitoba.ca (Dan Fandrich)
Newsgroups: comp.os.cpm
Subject: Re: Compression algorithms wanted
Keywords: crunch squeeze LBR
Message-ID: <1990Feb6.084036.18721@ccu.umanitoba.ca>
Date: 6 Feb 90 08:40:36 GMT
References: <774@nixpbe.UUCP>
Reply-To: shad04@ccu.UManitoba.CA (Dan Fandrich)
Distribution: comp
Organization: University of Manitoba, Winnipeg, Manitoba, Canada
Lines: 28

In article <774@nixpbe.UUCP> josef@peun11.uucp (Moellers) writes:
>I am writing a program to unpack .LBR archives on UNIX (perhaps pack later).
>I have the structure of the archive (which is fairly simple).
>
>What I am looking for is a description of the compression algorithms
>used when squeezing or crunching files (i.e. generating *.?Z? or *.?Q?)

Don't forget *.?Y? !  This is the LZH compression algorithm which was ported
to CP/M last September.  The file -SOURCE.NOT contained in the CRLZH11.LBR
library (the cruncher/uncruncher files) contains the sentence:

     "Most of the 'interesting' stuff is in the LZH encoding and decoding
      algorithms, anyway, which are released in .REL (and .SLR) format
      ONLY at this time."

I wouldn't think the algorithm would be much (if at all) different from the
LZH program available for some time for MS-DOS.  Don't know if you can get
specs for it, either.  The author of the CRLZH routines for CP/M is
R. Warren and he gives the number of The Elephant's Graveyard data line
(619) 270-3148 where he can be reached.  That might be another good place to
ask questions about all the compression routines (I've never them myself,
though).

-- 
>>> Dan Fandrich

Internet:   shad04@ccu.umanitoba.ca
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