Simtel MSDOS 1992 September/Simtel20_Sept92.cdr/msdos/sysutl/crunch10.arc/CRUNCHER.DOC

Text File | 1989-08-09 | 6KB | 131 lines

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                Cruncher (c) 1989 By Ori Berger, Tel [phone]

                                 Version 1.0


What is Cruncher?
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  Cruncher, like PAK, PKZIP and LHICE/LHARC, is a file compression program.
It differs from the other compression programs in its purpose, and its way
of operation. All of the file compressors (PAK,LHARC/ICE,PKZIP etc) create
output files that can later be extracted to their original form. Cruncher,
however, creates executable output files that extract themselves into your
computer's memory,  and then run themselves.  Crunched files do not create
temporary files, as opposed to SEA ARC.

How is Cruncher used?
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  Cruncher can get its parameters both from the command line and from  the
keyboard. For first time use, simply run cruncher using "CRUNCH" <CR>. You
should now be asked to give the input file name. It should either be a COM
file or an EXE file, and you should supply the extension as well.
  Then you shall be asked for the input file name; The output file will be
an EXE file, so if you type an extension, it must be EXE.  If no extension
is provided, Cruncher will assume .EXE extension.
  If you entered both file names correctly, you should now see the message
"--> Compressing " followed by 16 characters. This line shows you how much
of the input file has been processed; When this line is finished, it means
that Cruncher has completed the compression of the file.  You will then be
notified of how much bytes were saved by Cruncher    (This number might be
negative, which means that the Crunched file takes  more  space  than  the
original one.

  If you are already familiar with Cruncher, you could simply put the file
names in the command line, I.E.
"CRUNCH [input file .COM | .EXE [output file [.EXE]]]". If the output file
name is omitted, you will be prompted for it.

What can Cruncher do? What can't Cruncher do?
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  Cruncher can save you space. However, some files are not compatible with
Cruncher; These are files that access themselves.  It  is not possible use
Cruncher with such files, nor is it possible to detect such  files  before
running them.  Make sure your Crunched file is fully working if you intend
to delete the original.
  Though Crunched files do not show the text  (or the program) inside them
when inspected with programs like  "The Norton Utility"  and "PcTools", It
is not recommended to use Cruncher  as  a form of text protection - It can
be easily removed with a little knowledge of Machine Code.

What are the improvements over beta version 0.1?
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  Sorry folks.  No speed improvement.   The main feature that was added to
Cruncher is error checking. I have added extensive  error  checking,  even
the types you seldom need, like not accepting devices for files. I believe
you will find the new user-interface satisfying.

What are the error messages Cruncher can display?
═════════════════════════════════════════════════

  Cruncher can display the following messages:

- File not found --> (filename.ext)

This error means that the file you specified does not exist.

- Path not found --> (filename.ext)

Again this means that you had an error specifying the file name.

- Disk full

There is not enough free space on the target drive.

- Cannot perform compression on devices

You have specified a device name instead of a file name (E.G. COM1, PRN etc).

- Input file name must have <.COM> or <.EXE> extension

You have specified a file that is not a .COM or an .EXE file.

- Output file must be an <.EXE> file

You have specified a file extension other than .EXE for the output file. use
no extension at all or .EXE extension.

- Output file already exists

Cruncher will not overwrite any existing file. Specify a new filename.

Additional information
══════════════════════

  I am currently using Dynamic LZ coding, 9-12 bits with Table Clearing.  I
will be happy to adopt any other method that out-performs mine,  but it has
to come with a commented source. I must thank Tom Pfau for his  LZCOMP/DCMP
file compression program, from which I learned a lot about  LZ  coding.  If
you are interested in technical details, get APPNOTE.TXT from PKWARE ARC or
from NARC21.
  Also, I must say the idea came to me when seeing something similar on the
C64; A program called Time-Cruncher. It used RLE encoding, which was OK for
the C64 but gave poor results when used on the IBM.

Distribution policy
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You may copy Cruncher as long as the following conditions are met:

- No fee whatever is charged; Not even handling fee.
- Neither the program nor the documentation is changed;
- The program and its documentation stay intact;
- It is not used in any commercially or non commercially sold software.
- The copyright notices are not removed.

Anything else?
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  You can contact me on Echo-Mail. If you do not have a modem, you can call
me voice on 03-5401519. You will also be able to find new versions of  this
and other programs in Atari Blues BBS, tel [phone], 24 hrs, 2400 baud