================================================================
Title                   : Dzip v2.9

Authors                 : Nolan Pflug, Stefan Schwoon

Email Addresses         : radix@planetquake.com, schwoon@in.tum.de

Description             : Dzip is a program for file compression.
                          It's compression is on par with standard .zip file
                          compression and is sometimes marginally better.

                          Dzip's original purpose was to compress demo
                          recordings of the id software game Quake much better
                          than any other program, and it still does this.

                          Check out the Known Bugs section if you're
                          using Netscape!

                          This release includes the source files and execu-
                          tables for Linux, Windows, Solaris and Mac OS-X.
                          A powerfull Windows graphical version is also
                          available.

                          Information on how to compile executables by
                          yourself for other platforms is included in the
                          source download (it's fairly straightforward).

Installation            : Put the appropriate dzip exe for your system wherever
                          you want it.

Credits                 : Nolan had the idea for this program, maintains the
                          Windows executable and the graphical user interface.

                          Stefan executed Nolan's original idea, and now
                          compiles and tests the linux and solaris versions.

Additional Credits to   : Jean-Loup Gailly and Mark Adler whose Zlib
                          compression library is used by Dzip (see inside
                          source package for more information).

                          Michael Hudson for providing the OS-X binary.

                          Anthony Bailey for writing the original Quake demo
                          parsing source and for help with the Visual C++
                          compiler.

                          Uwe Girlich for the dem specs.

                          All the people at Speedcon for being there
                          and giving us a great time.
                          
================================================================

More detailed instructions

Dzip runs in one of several modes of operation depending on
the command line switches you give to it.

Running Dzip without any arguments will give you a list of
possible options which are discussed in greater detail here.

General purpose option: -f
  Normally, Dzip will refuse to overwrite existing files.
  This is a simple policy to prevent you, the user, from
  shooting yourself in the foot too easily... you can still
  shoot yourself in the foot if you want, but you will need
  to say so explicitly :) If you provide Dzip with the -f
  switch, it will happily overwrite existing files if it
  thinks it needs to.

General purpose option: -e
  Since v2.9 Dzip will continue execution after most errors, such
  as a CRC error on extract or a problem reading from a file.
  With this option the program will quit when the first error is
  encountered.

Compression: dzip [-e] [-f] [-0 .. -9] <filenames> [-o <outputfile>]

  In this mode, Dzip will take specified files and compress them into.
  a new dz file.  If -o is not specified, the name of the first filename
  given will be used for the name of the dz file.  The filenames can
  contain wildcards or directories, in which case the entire directory
  is added.

  The -0 to -9 switches set the compression level for zlib. -0 is no
  comression at all, and -9 is the best, but there is not much difference
  between -9 and even -1.  The normal compression used is -6.

  Examples:
      dzip example.dem
        Compress example.dem, writing the result to example.dz.
      dzip example.dem example.txt
        Same as before, but also put example.txt into example.dz.
      dzip example.dem -o another.dz
        Compress example.dem, writing the result to another.dz.
      dzip pak0.pak readme.txt -o marathon.dz
        Get all the files from pak0.pak, compress them and write
        the result to marathon.dz.


Decompression: dzip -x [-e] [-f] <dzfiles>

  When invoked like this, Dzip will treat the filenames given to it
  as .dz archives and try to extract their contents. 

  Example:
      dzip -x example.dz
        Extract files from example.dz.


Verifying an archive: dzip [-e] -v <dzfiles>

  This switch simulates the extraction of a dz archive without
  actually producing any files. This is useful for testing the
  archive and checking if it will decompress correctly.

  Example:
      dzip -v -e *.dz
        Verify every dz file in the current directory and quit on
		any error.

List an archive: dzip [-e] -l <dzfiles>

  Lists the contents of a dz file.

Add files to an exisiting archive: dzip [-e] -a <dzfile> <files>

  Opens <dzfile> and then adds <files> to it, similar to compression
  with no switches.

Delete files from an exisiting archive: dzip [-e] -d <dzfile> <files>

  Opens <dzfile> and then deletes <files> from it.  The file names list
  must match exactly a file that is actually in <dzfile>, ignoring case.


================================================================

Version history:

18.07.02: Version 2.9
          added -a and -d to add/delete files from existing dz
          add compression of whole directories
          added error continuation and -e switch to quit on first error
          added support for 2-4GB files on some platforms
          changed layout of -l listings

14.05.02: Version 2.8
          fixed problems with compression/uncompression of .dem
           files that were not compliant Quake demo files
          updated zlib to v1.1.4

24.01.01: Version 2.5
          extraction of quake demos is now 4x or more faster
          fixed a few minor problems

24.10.00: Version 2.2
          fixed rare dem encoding problem with out of order spawnbaseline messages
          while adding files, protection against bad .pak files

24.08.00: Version 2.1
          fixed a few more dem encoding problems (Remaic-related)
          better handling of tiny files
          added support for Nehahra .dem's
          other small bug fixes

28.07.00: Version 2.0
          slightly improved compression
          significantly faster
          removed -p option; dzip now remembers if a file
           was in a pak and re-creates the pak automatically
          fixed bugs for demos edited with demix or other tools
          date and time of files are preserved
          now displays compression ratio
          finally fixed all bugs with wildcard and path expansion

01.07.00: Version 1.2
          fixed wildcard bug in Windows version
          improved Hipnotic compatibility

21.06.00: Version 1.1
          added wildcard expansion for Windows (thanks Nolan)
          fixed a bug during decompression

20.06.00: Version 1.0
          initial public release

================================================================

Results (from v1):

I tried Dzip on different kinds of demos to see how well it
would compress them; these are the results.

Demos            Zip size   Dzip size   Ratio

SDA Nightmare
run records        3.51M      1.78M     50.6%

SDA Nightmare
100% records       9.55M      5.20M     54.4%

Marathon of Quake
on Nightmare       7.53M      4.48M     59.5%

Collection of
Deathmatch demos   9.53M      5.60M     58.8%

Devil's Covenant
movie demos        1.85M      0.59M     31.8%

================================================================

Future plans:

Just work on the GUI.  Baring bugs there won't be any updates to
the cmd line versions for a while.

I'm sure there is some interest in expanding the concept of demo
compression to other games/formats like QuakeWorld, Quake2 etc.
Also, I'm fairly confident that the ideas used in Dzip can be
successful for these games, too. However, we were only interested in
demo compression for Quake because of the large size of the demos
on SDA.  Feel free to use the source code to create compression of
other file types!

================================================================

Known Bugs:

This is not really a bug in dzip itself, but we mention it anyway:

Saving a dz file in Netscape under Windows that is on an http 
connection may corrupt the file. The reason for this is if the
webserver is sending the file as plain text since it doesn't 
recognize the extension, then Netscapes messes up all the line
feeds. Adding 'application/x-dzip' as a mime-type for .dz files 
on the server will fix the problem.

================================================================

* Copyright information *

Use of this program is free of charge.
Use of the source code is subject to the conditions pointed
out in the readme file accompanying the source code.

* Where to Get This *

The Dzip homepage is at http://planetquake.com/sda/dzip/

* Related websites *

Speed Demos Archive
        http://planetquake.com/sda/

Quake done Quick website
        http://planetquake.com/qdq/

Demtool
        http://planetquake.com/qdq/demtool.html

The demo specs page
        http://planetquake.com/demospecs/

