brad@looking.on.ca (Brad Templeton) (03/28/91)
Archive-name: compression/encoding/abe/1991-03-27
Archive: uunet.uu.net:/ClariNet/abe.tar.Z [137.39.1.2]
Original-posting-by: brad@looking.on.ca (Brad Templeton)
Original-subject: Re: mailable binary
Reposted-by: emv@msen.com (Edward Vielmetti, MSEN)
I also agree that this makes little sense, unless you are running on
DOS and the software tools approach is more difficult.
Keep the compressor and the asciifyer independent. You want to be
able to switch compressors at will, or not compress at all. You also
might want to switch ascii convertors at will.
ABE was designed to do just about everything you want in an ASCII
encoder. It can take inut from a pipe, such as your compression program.
Why write two programs when "compressor <args> | abe <args>" will do
it as a one-line shell script.
Among ABE's features by the way are:
Choice of ABE1 (94 characters) or ABE2 (86 characters) or
UUENCODE encoding.
Automatic blocking, with each block directed to a pipe
(like "|mail user") if desired.
Files are often smaller, and compress well.
Most printable characters map to themselves, so strings in
binaries are readable right in the encoding.
All lines are indexed, so sort(1) can repair any random
scrambling of lines or files. (This can be turned off.)
Extraneous lines (news headers, comments, signatures etc.) are
ignored, even in the middle of encodings.
A PD tiny decoder is available to include with files for first
time users.
Files can be split up automatically into equal sized blocks.
Blocks can contain redundant information so that the decoder
can handle blocks in any order, even with reposted duplicates
and extraneous articles.
Files with blank regions can be constructed from multi-part encodings
with damaged blocks.
Multiple files can be placed in one encoding.
The decoder is extremely general and configurable, and supports many
features not currently found in the encoder, but which other encoder
writers might fight useful.
For example, if a multi part abe encoding was sent to you in random order,
you can often just say "dabe <mailbox>" and get the files out.
Abe was posted to comp.sources.misc some time ago, it's also on UUNET in
the 'clarinet' ftp directory, I think. It's free.
BTW ABE uses 86 characters in the ABE2 encoding format, which is
EBCDIC proof. The characters to avoid are:
! ` [ \ ] ^ { | } ~
Plus spaces, newlines, DEL, and all control characters, of course.
--
Brad Templeton, ClariNet Communications Corp. -- Waterloo, Ontario 519/884-7473