Newsgroups: comp.compression
Path: utzoo!utgpu!watserv1!watmath!looking!brad
From: brad@looking.on.ca (Brad Templeton)
Subject: Re: How to code to a text file.
Organization: Looking Glass Software Ltd.
Date: Mon, 25 Mar 91 02:41:11 GMT
Message-ID: <1991Mar25.024111.13312@looking.on.ca>
References: <550@spam.ua.oz> <JAFFER.91Mar23192610@zohar.ai.mit.edu>

If the encoded data is not random data (ie. the output of a compressor) then
consider the ABE encoding.   You can find abe in the comp.sources.misc
archives, and on uunet in ~ftp/clarinet/abe.tar.Z, I think.

ABE works with two versions of the safe character set.  The more restrictive
one is EBCDIC proof.

It splits the bytes into 3 or 4 sets, and uses shift characters to change sets.
If possible, it puts the most common bytes in the first (default) set.  On
text files, for example, ABE encodes with almost no expansion, and the encoding
is readable!   This also applies to binaries, as it always tries to encode the
safe characters as themselves when it can.

If the bytes are totally random, ABE is more expansive than it should be,
but still not too far off what uuencode does.
-- 
Brad Templeton, ClariNet Communications Corp. -- Waterloo, Ontario 519/884-7473
