Power-Programmierung/CD1.mdf/packer/lzexe/lzeshl20.doc

Text File | 1990-03-24 | 9KB | 213 lines

                                 LZESHELL.EXE
                                 Version 2.00

     ┌───────────────────────────────────────────────────────────────────┐
     │  An English language shell program for automating the use of      │
     │  Fabrice Bellard's EXE file compression utilities:  LZEXE for     │
     │  compressing EXE files; UPACKEXE for unpacking EXE files that     │
     │  have been packed with Microsoft's EXEPACK utility; and COMTOEXE  │
     │  for converting COM files to EXE files so they can be compressed. │
     └───────────────────────────────────────────────────────────────────┘

     (This version of LZESHELL is similar to versions 1.00 and 1.01, but
      it automaticaly runs three of Bellard's file compression utilities
      instead of two.)



AUTHOR:  Pete Petrakis, CIS 76555,1175


DESCRIPTION

This program is designed to work only with version 0.91 of LZEXE, a utility
that can compress EXE files substantially while leaving them executable.  The
compressions LZEXE achieves are usually in the range of 30 to 40 percent,
although they are often higher than that.  Programs compressed with LZEXE
decompress themselves when they are run.  The decompression time is negligible.
LZEXE was written by Fabrice Bellard, of Grabels, France and is still under
development.  It is a free program, but Mr. Bellard retains the copyright.

  Version 0.91 of LZEXE overcomes version 0.90's problem of excessive load
memory size for compressed files.  The compressed files now take about the same
amount of memory to load as they did before compression.  For this reason my
previous shell program LZEFIX, which ran Microsoft's EXEMOD header utility
to reduce the excessive load sizes created by version 0.90, should not be used
with version 0.91.  It isn't needed.  In fact it could cause problems
(including having to reboot your system) if you try to use it with this newer
version of LZEXE.  Accordingly, LZESHELL makes no adjustment to the headers of
compressed EXE files.

  Unlike the previous version of LZEXE, version 0.91 prompts, in French, for
user input, depending on what it finds out about the file you have asked it
to compress.  LZESHELL translates the prompts into English (the translation
is not literal) and feeds your responses to LZEXE.

  That's not all it does, however.  LZESHELL version 2.0 automates the use
of three of Bellard's utilities:  LZEXE v0.91, UPACKEXE v1.00; and
COMTOEXE v1.01.

  UPACKEXE unpacks EXE files that have been compressed with Microsoft's
EXEPACK utility so LZEXE to do an even better compression job on them.
COMTOEXE converts .COM files to .EXE files so they can be compressed with

                                   -1-LZEXE.  The previous versions of LZESHELL (1.00 and 1.01) were designed to run
LZEXE and UPACKEXE, but not COMTOEXE; that program had to be run separately.
Version 2.0 runs all three automatically.

  Version 0.91 of LZEXE can detect files that have been EXEPACKed.  When it
does, it tells you so and asks whether it should continue the compression or
quit so you can run UPACKEXE first.  In that situation, you would normally end
up running two programs manually.  When you use LZESHELL, however, you don't
have to quit if you want to use UPACKEXE.  LZESHELL translates the prompt into
English, and if your response is that you want to unpack the file before
compressing it, it immediately runs UPACKEXE.  Then it runs LZEXE again
to complete the compression.  In other words, you don't go back to DOS until
both programs have been run.

  If you run LZEXE alone and tell it to compress a .COM file (using the
command:  LZEXE filename.COM), it won't do it.  Instead it will quit, with
advice to convert the file to an .EXE first with COMTOEXE.  Again, this
means running two programs manually.  If you use LZESHELL, however, the
conversion of the .COM file to an .EXE file by COMTOEXE proceeds automatically,
followed automatically by compression of the .EXE version by LZEXE.

  A point to remember about COMTOEXE is that it doesn't take your word that
the file is a .COM file, because .EXE files sometimes mistakenly get named
.COM (such files will still run).  Instead, COMTOEXE checks the file header
to see what kind of executable file it really is.  If it sees the mark of an
.EXE file there, it prints a warning and stops.  When you are running it
through LZESHELL, however, the warning causes the falsely named *.COM file to
be renamed *.EXE, and the compression with LZEXE then proceeds automatically.

  In summary, the purpose of LZESHELL is to take control of all three of these
fine utilities.  You only need to run one program, LZESHELL, and it runs the
others as needed.

  Both UPACKEXE and LZEXE save source files as backups, changing their names
to *.OLD.  This can create a problem when you run UPACKEXE then run LZEXE.
The *.OLD backup file saved by UPACKEXE will be replaced by the *.OLD file
saved by LZEXE -- you end up losing the EXEPACKed *.OLD file.  LZESHELL
eliminates this problem by immediately renaming the *.OLD file produced by
UPACKEXE to *.OPK.  This leaves you with two backup files -- one for the
original EXEPACKed file (*.OPK) and one for the unpacked file (*.OLD).  The
third file will be your LZEXE-compressed EXE file.  If the compressed file
works, you can remove both backup files from your disk.  Otherwise, you can
erase the compressed EXE file and rename one of the backups to *.EXE (probably
the EXEPACKed one, *.OPK, since it's the original and it's smaller).

  LZESHELL also generates English prompts for another situation that LZEXE
v.0.91 detects, namely the use of overlays by the EXE file.  Here you are
given the choice of aborting the compression or continuing it (taking the
chance that the compressed file won't work).  UPACKEXE v1.00 detects "internal"
overlays (I'm not sure what those are), but in that situation it only issues
a warning and requires no user choices.  LZESHELL translates the warning into
English.

                                   -2-  Finally, LZESHELL adjusts the timestamp on derivative files so they are the
same as in the original file.  In contrast, LZEXE, UPACKEXE, and COMTOEXE, when
run by themselves, always give the new file the current date, which some people
feel is a shortcoming since it obliterates a useful identifier.


RUNNING THE PROGRAM

LZESHELL, LZEXE (v.0.91), UPACKEXE (v1.00), and COMTOEXE (v.1.01), or their
directories, should be on your system's path (use the DOS PATH command to do
this, preferably in an AUTOEXEC.BAT file).  This will allow you move freely
from directory to directory to compress EXE files.  You should always go to the
directory of the file you want to compress so your source and derivative files
can stay together and receive the same timestamp as the original.

Compressing EXE files:

  To compress an .EXE file, type the following at the DOS prompt:

                  LZESHELL [EXE file to be compressed]

Use of the .EXE extension is optional.  If you don't use an extension, LZESHELL
will assume it's an .EXE file.


Compressing COM files:

  To compress a .COM file, type the following at the DOS prompt:

                    LZESHELL [filename.COM]

Notice that you have to use the .COM extension on the command line if the
file you want to compress is that type.  That extension acts as a flag that
tells LZESHELL that the first thing it must do is run COMTOEXE to convert
the file to an .EXE file before compressing it with LZEXE.  If you don't
use the .COM extension, you will get a "file not found" error (unless you
happen to have an .EXE file with the same first name).

  As noted, an .EXE file that has been erroneously named *.COM will not be
processed by COMTOEXE.  However, the message that COMTOEXE prints in that
situation signals LZESHELL to rename the file to *.EXE, then run LZEXE to
compress it.


DISPLAYS

  Translated warnings and prompts will appear in a box on your screen.  At
the end of the compression a "scorecard" will appear showing you the file
size before and after compression, the size reduction in bytes, and the
percent reduction.



                                   -3-DISTRIBUTION

LZESHELL may be freely distributed provided it's not modified and no money
is charged for it.  Please be sure this document accompanies it.


DISCLAIMER

Pete Petrakis accepts no responsibility or liability for any mishap
resulting from the use of LZESHELL.  To protect yourself against loss of
valuable files you are advised to keep backups in a safe place or check the
performance of compressed files thoroughly before discarding their backups.

  LZEXE and perhaps its associated programs are still under development, so
there is no assurance that this particular version of LZESHELL will be
compatible with future revisions Mr. Bellard might make.  I will try to update
LZESHELL as needed to maintain compatibility.  Revisions will intially be made
available on the IBMSYS Forum of Compuserve (type GO IBMSYS).

                                        Pete Petrakis
                                        1236 River Bay Road
                                        Annapolis, Maryland 21401































                                    -4-