Short:    A packer for the xpk-package, V1.0
Author:   K. Dagef"orde
Uploader: dagefoer@rzcipa03.rz.tu-bs.de
Type:     util/pack

---------------------------------------------------------------------------
                                    RAKE
                         A cruncher of the LZ77 family
                             for the XPK-package
                                Version 1.00
                        Copyright 1994 by K. Dageförde

                              Status: FREEWARE



                             License/Disclaimer
                             ------------------

   This  library  may  be  freely  distributed, as long as it is kept in its
original,  complete,  and  unmodified  form.  It may NOT be distributed in a
commercial package of any kind without my permission.

   This  program  is  distributed  in  the  hope that it will be useful, but
WITHOUT  ANY  WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE.


                                Installation
                                ------------

    You'll  need  to install the XPK package first to use this library.  The
XPK  package  should  be available on most Bulletin Board Systems, so try to
get it there.

    If  you  already have the  XPK package  installed, add  this  library to
your system simply by copying the xpkRAKE.library  to your LIBS:Compressors/
directory, or  if you've got a 68020 (or greater) processor, you should take
the xpkRAKE.library.68020' instead.


                                Description
                                -----------

    RAKE is an  XPK packer sublibrary  which  implements a highly  optimized
form  of  the popular  LZ77 compression  algorithm. It  uses  static huffman
coding   for   the  'len'   and  a  three-step  coding  for   the   'offset'
information.  The  major  feature   of this packer  is the  highly optimized
algorithm for tracking down redundant data.


                                 Statistics
                                 ----------

    Following  is  a table  briefly listing some  comparative statistics for
NUKE  and  RAKE.  These  were   generated   by   xBench   on   an   A3000/25
with 2MB ChipMem and after all 3MB FastMem, using the AmigaVision executable
as data. Note that memory needs  don't include  xpkmaster.library's buffers.
The results for RAKE were evaluated using the 68020 optimized version.


                                                        | Memory usage while
Packer  UComp   Comp    CF   CSpd    USpd               | packing  unpacking
----------------------------------------------------------------------------
RAKE   594712 322872 45.8%  66226  401832 (415882 rare) |    256K         0K
NUKE   594712 326908 45.1%  38368  447151 (526293 rare) |    192K         0K


    Maybe that this A3000 was not a standard  xpk benchmark  system, because
some  packers seemed to be  slower  than  reported by xQuery, e.g. NUKE with
about  630K/s  at  decompression.  Thus  RAKE   should  also  be  faster  at
decompression in the same way.  Nevertheless, xQuery  reports the results as
listed above for RAKE.


                                  History
                                 ---------

                 V1.0 first public release (68000,68020)




                              Contact Address
                              ---------------

                        dagefoer@rzcipa03.rz.tu-bs.de
                                     OR
                          dagefoer@ibr.cs.tu-bs.de


Thanks.