D J P
                                    ~~~~~

                          executable file compressor

                                 for DJGPP V2

                                 version 1.07

                                  by  ML1050

                         Copyright (C) 1996, 1997, 1998


 What is It?
 ~~~~~~~~~~~

    DJP is a fast and small executable file compressor for files produced by
 DJGPP V2. It uses an algorithm called LZO1X, which achieves an average
 compression ratio of about 0.56 on executable files, and can decompress
 at about 6-8 Mbytes/sec on an AMD 486DX4-100 with no memory overhead.
 (Decompression speed is defined as uncompressed size/decompression time.)


 How to Install?
 ~~~~~~~~~~~~~~~

    If you have the binary distribution:

        unzip mlp107b.zip     or   pkunzip -d mlp107b.zip

    If you have the source distibution:

        unzip mlp107s.zip     or   pkunzip -d mlp107s.zip
        cd contrib\djp\src
        unzip lzo.zip         or   pkunzip -d lzo.zip
        make


 How to Use?
 ~~~~~~~~~~~

    Simply type:

                  DJP [options] <filename> [<filename list>]

    Use the -d option to decompress files.
    Use the -t option to check the integrity of compressed files.
    Use the -l option to list the compression ratio.

    Use the -b option to keep backup files.
    Use the -s option to put the decompressor into the stub.
    Use the -c option to produce COFF output.
    Use the -1 option for the fast (and worse) compressor.
    Use the -q option for quiet mode.
    Use the -h option for command line help.
    Use the -i option for software license.
    Use the -0 option to ignore the default options (see below). You should
                      always use this in Makefiles.

    <filename> can be a stubbed .EXE or a stubless COFF image.
    You can use wildcards too.


 Stubbed vs. stubless decompressor
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    Since DJP 1.04 there is a new feature: the stubless decompressor. Here are
    the main differences between the stubbed and the stubless one.
    
    Stubbed
    -------

    + simple self check against viruses
    ñ you can't debug the compressed files :-)
      (at least not with the standard DJGPP tools)
    - alters stubinfo: so if some of your (un)compressed files were stubedited,
      you must stubedit them after the (de)compression again
    - if you have "symbolic links" to a compressed file, than you have to
      replace all the links with djpstub.exe.

      So if you compress grep.exe, then you should replace egrep.exe and 
      fgrep.exe.

                    DJP -s grep.exe

                    copy djpstub.exe egrep.exe
                    stubedit egrep.exe runfile=grep

                    copy djpstub.exe fgrep.exe
                    stubedit fgrep.exe runfile=grep

      Or you can use DJPLINKS.BAT (it's in the /bin directory).

    Stubless
    --------

    + works with the PMODE/DJ stub 
    + works with debuggers (but you won't have debug info!!)
    + no problems with "symbolic links"
    + doesn't alter stubinfo.

 
 Default options
 ~~~~~~~~~~~~~~~
    
    You can change the default options for DJP 1.07 through an environment
    variable called DJP_OPTIONS. You can do this with a SET DJP_OPTIONS= 
    statement in your autoexec.bat or via the DJGPP.ENV file. If you choose
    the latter method, just add a section to your DJGPP.ENV:
    
    [djp]
    DJP_OPTIONS=your favorite options for DJP  (-s,-b,-c,-q)
    
    For example if you don't like the progress indicator, and always want
    to keep the backup files, then set
    
    DJP_OPTIONS=qb
    
    After this, the -q and the -b option will have the opposite meaning if
    you use them on the command line. -b will delete the backup files, and 
    -q will show the progress indicator. Type DJP -h if you wanna see the
    actual state of the options (dynamic command line help :-)


 Legal Issues
 ~~~~~~~~~~~~

    DJP and the LZO package is covered by the GNU General Public License (GPL).
    
    The decompressor imbedded in each compressed image contains GPL code
    written by Laszlo Molnar and Copyright (C) by Markus F.X.J. Oberhumer.
    Compressed commercial and other images may be distributed by special
    permission of the authors without source, as long as the decompressor
    is only used for decompressing the image at program startup.


 Warranty
 ~~~~~~~~

    #include "as_usual_no_warranty.h"


 Thanks
 ~~~~~~

    DJ Delorie for DJGPP.

    Markus F.X.J. Oberhumer for LZO.

    You can get the full LZO package from:
       http://wildsau.idv.uni-linz.ac.at/mfx/lzo.html

    Charles W. Sandmann for the ideas with the stubless decompressor
       and for the beta testing.

    Salvador Eduardo Tropea for the beta testing.


 Contact
 ~~~~~~~

    Laszlo Molnar 
    email: ml1050@cdata.tvnet.hu


 History
 ~~~~~~~
    1.07  1998. 04. 20
                       My email address changed.
           DJP.C
          changed    : using lzo 1.04 : a little better compression

    ~~~~~~~~~~~~~~~~~~

    1.06  1997. 11. 24
           DJP.C
          changed    : Markus added lzo 1.01 support : a little better
                       compression, a little faster decompression
          new        : support for Allegro pakfiles
          bug removed: fixed incompability with strip.exe from Binutils 2.8.1
          bug removed: fixed temporary filename problem on chinese win0.95.
          bug removed: fixes for decompressing plain COFF files

           DJPSTUB.ASM
          changed    : uses stub.asm from djlsr202

    ~~~~~~~~~~~~~~~~~~

    1.05  1996. 12. 02
    
           DJP.C
          new        : -1 option for fast compression.
          new        : -l to list the compression ratio (thanks Markus). 
          new        : uses the checksum of the uncompressed image
          changed    : uses the LZO1X-999 compressor : better but slower
                       compression, faster decompression
          changed    : always use the safe decompressors
          changed    : built-in stubify
          bug removed: problem if the entry point of the executable > 0x11ff
                       (as in RHIDE beta 6)
          bug removed: DJP is DLM aware (hmm.. :-) now 
          
           DJPSTUB.ASM
          new        : simple self check 
          new        : prints an error message if decompression fails
          changed    : uses stub.asm from djlsr201 with #ifdefs
          changed    : uses the decompressor from the lzo distribution
 
    ~~~~~~~~~~~~~~~~~~
 
    1.04  1996. 07. 15

           DJPSTUB.ASM
          changed    : LZO1F decompressor
          new        : checksum for integrity checking (Adler32)

           DJP.C
          new        : -s,-c,-b,-t,-q,-0 options.
          new        : progress indicator
          changed    : using the LZO1F-999 compressor : better but SLOWER
                       compression, faster decompression
          bug removed: problem with strange .text section size in QUAKE.EXE
          bug removed: problem with an extra section in the COFF header
                       in UAE.EXE (The Unix Amiga Emulator)

           LZO1F_D.S
          new file   : LZO1F stubless decompressor in AT&T format.

    ~~~~~~~~~~~~~~~~~~

    1.03  1996. 05. 28

           DJPSTUB.ASM
          bug removed: problem with loading packed section if size%4 != 0
                       this was a serious bug, so you should recompress
                       all the files, that were compressed with DJP < 1.03
          new        : restored error messages 
          changed    : the decompressor runs in the 32-bit code segment

           DJP.C
          new        : adding decompressor
          new        : can compress plain, executable COFF files (inserts stub)
          new        : compression check
          new        : error messages
          changed    : using the LZO1-99 compressor : ~2% better compression

    ~~~~~~~~~~~~~~~~~~

    1.02  1996. 05. 07

           DJP.C
          bug removed: couldn't rename temporary file in certain cases

    ~~~~~~~~~~~~~~~~~~

    1.01  1996. 05. 06

           DJPSTUB.ASM
          bug removed: incorrect order of pop es and pop ds
                       
           DJP.C
          bug removed: doesn't try to compress already compressed files
          some minor changes

    ~~~~~~~~~~~~~~~~~~

    1.00  1996. 04. 27  Original release.

 EOF
 ~~~