zzip.txt

zzip-zzlib-src.zip. A new archiver that uses a BWT algorithm to achieve superior compression. The

+-----------------------------------------------------------------------------+
 Zzip/Zzlib version 0.36c  04-Jun-2001
 Copyright (c) 2001 Damien Debin, all rights reserved.
 Yet another block-sorting compressor for Windows 9x/Me/NT/2000 and Unix !
+-----------------------------------------------------------------------------+

Zzip is a new compression utility, still under development, which can compress 
files with a very high compression ratio. Compared to Winzip 7.0, you can gain, 
at least, 15 %. This utility uses an algorithm mainly based on the Burrows-
Wheeler Transform method developped by Mike Burrows and David Wheeler.

Warning : since this software is still in development, different versions are 
not cross-compatible. It means that a file compressed with zzip may not be
uncompressed with a different (newer or older) version of zzip.

Note : Zzip _can't_ uncompress pkzip/winzip files (*.zip).

* Zzip usage: 
  zzip [<command>] [<sw1><sw2>...] [<archive>] file1 file2 ...

  + <commands>
      a  Add files to archive
      e  Extract files from archive without pathname
         (zzip extracts all if no files are specified)
      x  eXtract files with full pathname
	     (zzip creates the path if it does not exist)
      d  Delete files from archive
      t  Test files in archive
      l  List contents of archive

  + <switches>
     -...  Block size (e.g. -3m,-3072k)
            + block size of 1 Mb : -1m
            + block size of 2347 kb : -2347k
     -a    Adaptive block size reduction
     -mx   MaXimum compression
     -mm   MultiMedia compression
     -q    Quiet (no output to screen)
     -r    Recurse subdirectories when compressing
     -s    Statistics about (de)compression

  + default switches are : -1m (block size of 1Mb)

  + -mx gives the best compression ratio but compression is 15% slower
  
  + -a is useful with binary or tar files, it reduces the block size adaptively
    to give a better compression ratio, but compression is 5% slower

  + -mm enables a special algorithm for image and wav files, use it only for
    multimedia files since it can give a worse compression ratio for regular
    files

  + If you don't specify any command, the default behaviour for Zzip is to 
    compress, by appending the extension '.zz' to every input file names and
    compressing them separately.

  + Willcards are allowed for input files.

* Zzip-sfx (only available for Win9x/Me/NT/2000) usage : zzip-sfx archive
  Zzip-sfx builds a self-extracting archive (exe file) from a zzip archive

* If you want to use Zzip in one of your program you can get a free dll (Zzlib)
  at Zzip website.

* The source code of Zzip/Zzlib is released under the GNU LGPL, you can 
  download it at Zzip/Zzlib website.

* If you want further information or if you want to report any bug, please mail
  me at [e-mail] or visit Zzip website http://debin.org/zzip/

* History :

  0.36c
  + bug fixes
  + unix version doesn't work any more, it will be delayed until I can get 
    access to a unix machine

  0.36b
  + source code is released under the GNU LGPL !
  + a new option '-s' to get stats about the (de)compression (only available 
    for x86 cpus)
  + bug fixes (unix version works !)

  0.36a
  + zzip-sfx, a new utility (only available for Win9x/NT/2000) for building
    self-extracting archives from zzip archives
  + a new adaptive block size reduction algorithm (switch -a)
  + bug fixes
  + a new web site ;) http://www.zzip.f2s.com/

  0.35g
  + bug fixes

  0.35f
  + compression and uncompression are somewhat faster (5% I think for regular 
    processors)
  + a new filter for text files (phrase replacement) has been implemented
  + better detection of multimedia files
  + bug fixes

  0.35e
  + compression is 5% faster, uncompression is 20% faster
  + the three algorithms have been merged into a single, please use now '-mx' 
    to get the best compression ratio
  + memory footprint has been reduced, the new memory usage is :
    - 6*block_size during compression
    - 5*block_size during uncompression
  + the range of block size has been enlarged up to 20*256kb=5mb (-b20)
  + a new switch (-mm) enables a new algorithm for images and wav files

  0.35d
  + a lot of functions have been added to the dll to manipulate archives
  + you can specify now which files you want to extract

  0.35c
  + zzip has been turned into a dll, so that you can use now zzip as a command
    line software or as a library in your program
  + compression/uncompression is slightly faster

  0.35b
  + the compression ratio has improved by about 1%, especially with Win32 exe
    and text files ; I can now compress the Calgary Corpus within 816,000 bytes
    and the Canterbury Corpus within 471,000 bytes

  0.35a
  + a major release
  + some nice commands have been added : deleting files in an archive, adding
    files (recursively or not) to an existing archive, extracting files with
    full pathname, listing contents of archive, testing archives
    (-> command line options have changed !)
  + some bug fixes (as usual ;)

  0.34f
  + some important bug fixes
  + the compression ratio with text files improved by 1% (thanks to Szymon
    Grabowski)

  0.34e
  + compression is about 5% faster
  + some bug fixes

  0.34d
  + (un)compression is about 10% faster
  + the compression ratio improved slightly (0.5%)
  + some bug fixes
  + options -b256,-b512... have been replaced by -b1,-b2...
  + a new compression mode for multimedia files (-mm)

  0.34c
  + uncompression is 10% faster
  + the algorithm selection is more efficient and faster

  0.34b
  + Another speed improvement, Zzip 0.34b is 15% faster than 0.34a, but memory
    usage has increased, so that there is now a new option '-lowmem' which
    limits memory usage

  0.34a
  + Zzip is now 10% faster
  + Zzip uses now 40% less memory, 7x block size instead of 10x
  + bug fixes concerning the archive feature and the i/o error handler

  0.33b
  + some various bug fixes
  + speed improvements (about 5% faster)

  0.33a
  + multiple-files-in-a-single-archive feature added
  + CRC32 control for each file of the archive

  0.32b,c,d
  + bug fix versions
  + unix platform

  0.32a
  + first quite stable version

+-----------------------------------------------------------------------------+
Damien Debin <[e-mail]>
http://debin.org/zzip/