Manual for HPACK LITE - A high performance archiver.

Program developped by Peter Gutmann.
(c) 1989-1992 Peter Gutmann.

This (cut-down) Atari version by Martin Braschler.

0. Introduction
"""""""""""""""

What an archiver is, should be known to everybody by now. A brief
description, though: with an archiver you can shorten a great number
of files (theoretically as much as you like) and put them into one
big file.
The reason to do this is that when you give the files away, nothing
gets lost, and that by the reduction room is saved on your storage
media. When you transmit data per modem via telephone lines, your
phone bill (and you probabely, too), will also be pleased by the time
gain.

HPACK LITE should be understood as an specialised archiver. It is not
intended to be a direct opponent to other archivers (as LHarc or ZIP),
at least not in this Atari version. Most of these other archivers were
developped distinctly to serve as universal compression tools, that
suit usage in every day life just fine.
HPACK LITE fails there, as it is just too slow. Reason for this is on
one hand the used methods, on the other hand the programmer that did
this Atari version. That is the reason, why this is only a cut-down
version: I just havn't enough time at the moment to spend for hour-long
work on HPACK and then, I'm no "assembler wizard", that's why the
(de-)compression routines are still in C. If you want to have a go on
them, though, just contact me.

On the other hand, HPACK is built for as-good-as-possible compression
ratios. Comparisons are hardly ever accurate, and the results consequently
tend to differ very much, but if you especially care for the lenght of
the resulting archive, you should not forget HPACK on the Atari. (You
know it: one isn't allowed to say: This programm is b***** than the other,
because...)
This is, I think, the major use for this version: I think HPACK LITE
will be used when program packages are transmitted via modem (e.g. when
they are downloaded from a BBS). Then the files are packed one time only,
and extracted just one time (after the download). Time doesn't matter
too much there, but size does.

OK, let's go:

1. Usage
""""""""

HPACK LITE is no full version of HPACK. It just contains Add, Extract,
Test and View.

HPACK LITE is a so-called TTP. After a double-click on the symbol on your
desktop a box will appear, where you enter your input, as explained below.

BTW, there are two different versions of HPACK LITE, one for all Ataris
with 680x0-CPU, and one for those with 68030 or better only. If you use
the slower version on a fast computer it will complain and ask you to use
the faster one. This is life: if you have a slow computer, you are forced
to use the slow version. If you've got a TT... I know, those that have,
are given..
Both versions are compiled using Pure C. After that they were compressed
using Pack-Ice 2.40.

Add
---

The command to add files is "a". Following is the name of the archive,
followed by the name of the files to add. This looks:

[Invoke HPACK, then enter:] a test file1.txt program1.prg

This will add the two files "file1.txt" and "program1.prg" to an archive
with the name of "test.hpk". The extension ".hpk" is appended automatically
by HPACK LITE.

You can also use "wildcards". E.g. "file?.txt" stands for file1.txt,
file2.txt, filea.txt... "fi*.txt" stands for file.txt, finance.txt...
HPACK has got a complete UNIX wildcard handling, i.e. to add all files,
you use "*" instead of "*.*".

If you want to add whole directory trees of files, you need to give
the recursive adding-switch. That looks like the following:

a -r test f:/folder/*

Note: HPACK LITE uses "/" as denoter for folder names, not "\". That's
like in UNIX.

Another goodie is the "unified compression". If you use this, HPACK uses
the result of the preceeding file to compress the current one.
If you compress many similar files (20 texts, 30 source codes, 10 printer
drivers or whatever), you can get astonishing compression ratios.
The result doesn't need to be better in all cases. If the files differ
very much, the archive can get actually longer. This may change in a
different version, a proposal of me on that point has been forwarded to
the original author.
If you want to upload a program package to a mailbox, it is well worth
to test both possibilites (with or without "unified compression"), and
take the shorter archive. The people that download it will be gratefull,
and the phone company annoyed (if that isn't worth it..)

Turn "unified compression" on by giving the "-u"-switch.

That is: a -u [-r] test file.txt folder/*....

Last possibility: you can encrypt your archives. Give the -c switch to
do that. After it has started, HPACK LITE will prompt you for a pass-
word then.

Example: a -c test file.txt

HPACK generally doesn't wait for a key after exiting, alter that by giving
the -h switch.

Extract
-------

Extracting is invoked by giving the "x" command. HPACK LITE checks auto-
matically if the data is compressed with "unified compression" or not.
Same with encryption, it will prompt you for a password if neccessary.
If you want to restore the directory tree, you must give the -r switch,
though.

That is: x [-r] test [files..]

By specifying some files, you can extract an archive partially.
Please note, that if you unpack a single file out of a "unified comp-
ression"-archive, i.e. the 30th file out of 40, all 29 preceeding files
need to be extracted prior to the 30th (they aren't written of course).
This is because every file depends on all preceeding ones in this case.
This is not tragical, as in general, all files are extracted at once
(especially after a download).

Test
----

This is the same as extract, with the difference, that the extracted
data isn't actually written. HPACK LITE calculates a checksum for each
file when adding it, and this gets checked now. This is handy, if you
want to distribute files, and want to check their integrity before
giving them to hundreds of people.

You use this by: t [-r] test [files..]

Just like extracting.

View
----

If you want so, HPACK LITE shows you a listing of all files in the
archive. Command for that is "v". If you want to see the subdirectories,
too, give the -r switch. Viewing can be restricted to some files only.

That's: v [-r] test [files..]

2. Bugs and limitations
"""""""""""""""""""""""

First: This is no full version of HPACK. If you take a look at the 
original manual (included), you'll see, that HPACK is very powerful.
However, I lack the time to complete a full version at the moment. I
do hope, however, to do so some time.

Second: The program has a little bug when showing the progress of
packing (drawing the "o"'s): If a very long file is packed, the "o"'s
are shifted a little out of their place to the left. This isn't nice,
but harmless. The error must be in HPACK's own output routines, I'm
looking for it.

Third: If you enter at extraction (or testing or viewing) a wrong pass-
word, two bombs appear. This is very hard to avoid, as HPACK of course
doesn't store the correct password anywhere. Consequently, it just starts
to decrypt with the wrong password. Strange things can happen then.
This isn't tragical, just restart HPACK and reenter your input. I'll
try to find a solution.

If you find other bugs/problems, please tell me (addresses see below).
Please include with a bug report: a description of your hardware
(computer, monitor..), all resident programs, the command that did
reveal the bug, and all other assistance you can provide me with.

4. Legal bits
"""""""""""""

To start:

Neither the autor of the original program (Peter Gutmann), nor the
author of the Atari version (Martin Braschler), take any responsibility
for the correct function of this program or for damages arising out of
usage of it. Their is no replacement for damages and we are not forced
to correct the program.

HPACK LITE may only be distributed as complete package. This includes:

DOCUMENT/HPACK.DOC
DOCUMENT/README.1ST
DOCUMENT/REGISTER.DOC
HP_LITE.TTP
HP_L030.TTP
LIESMICH.TXT
README.TXT

And: HPACK is shareware!

This is however treatened very lazily. That means: you MAY USE HPACK
WITHOUT registration. If you use it VERY often, or in business, however,
you should consider registering it. Send all money to the original
author (Peter Gutmann). See REGISTER.DOC for further information.
For private use, HPACK is free. Enjoy it.

HPACK LITE, the Atari version, is Pseudo-Messageware. I.e., if you use
it, you should send me a note. You don't need to, this is voluntary.
But I think, this shouldn't be too much trouble for anyone.

You can send me an EMail to:

faramir@ezinfo.vmsmail.ethz.ch (Internet) or
Martin Braschler @ FR (MausNET).

You'll surely find a gateway to one of these addresses!

If not, I will be happy if you send me a Postcard or Letter.

Note: I'll try to answer every note (if wished so). Should you not get
any reply, your (or my) mail maybe got lost, or I'm on holiday or what-
ever. Just send a second mail. If you want a reply to a letter, send
me an enveloppe and return postage (i.e. international reply coupons).
I won't reply otherwise.

OK, and here my address:

Martin Braschler
Brunngasse 16
CH-4124 Schoenenbuch
Switzerland

Enjoy HPACK LITE!
