Saturday, February 11, 2001

Dear MacPerl Users,

this is the Compress-LZF-0.05 module with shared libraries compiled for MacPerl. Shared 
libraries run only on PPC and CFM68K versions of MacPerl, not non-CFM 68K versions.

This was compiled with MPW's MrC (PPC) and SC (68K). Passed all tests on both
architectures (thanks to my old Mac LC :). However, let me know of any problems you
might encounter.

You can download the module and the readme from my website via

    http://usemacperl.webjump.com/index.html

or from my CPAN directory

    $CPAN/authors/id/T/TW/TWEGNER/


INSTALLATION
============
The module is best installed using Chris Nandor's installme.plx droplet. Simply 
drop the packed archive or the unpacked folder on the droplet. Answer the 
upcoming question "Convert all text and MacBinary files?" with "Yes". This should 
install the module properly. 

The installer is part of the cpan-mac module, available from CPAN 

    http://www.perl.com/CPAN-local/authors/id/CNANDOR/

or via Chris Nandor's MacPerl page 

    http://pudge.net/macperl/ .
	

CHANGES
=======
In the 'Mac_changed' folder, you will find a back-up of all the *ORIGINAL* files, 
that have been changed:

LZF.xs
MANIFEST
README

Actually, the only source file I've changed is 'LZF.xs'. All the changes I've made 
can be found by searching for the phrase '###TOM', if you are interested in.

I've added two MPW worksheets (PPC and 68K) to the distribution. This way you can
build the module yourself, if you like. However, you will need the MacPerl source 
distribution [1] and the FREE MPW development environment, available from Apple [2]. 
You may also want to take a look at the Macintosh Perl XS Tutorial [3]. It's best 
to open the worksheet and execute the commands step by step. Read and follow the 
instructions I've provided for each step of the build process.

In the build process for CFM68K some extra preparation is required for the source 
file(s). To help you in this procedure, I've added the file 'LZF_68K.xs'. This 
should be the input file for the XSUBpp compiler in the CFM68K build process.

In that 68K XS file, the header declarations are bracketed with #import pragmas.
This special pragma treatment is needed for the SC compiler and the ILink linker  
(see the Macintosh Perl XS tutorial for details). Follow the steps in the 68K MPW
worksheet and everything should be fine.

Have fun.

--
Thomas Wegner

toms_email@gmx.de


References:

[1] MacPerl 5.004 source  <ftp://sunsite.cnlab-switch.ch/software/platform/macos/perl/Mac_Perl_520r4_src.bin>
[2] Apple's MPW  <http://developer.apple.com/tools/mpw-tools/>
[3] Macintosh Perl XS Tutorial  <http://macperl.com/depts/Tutorials/XS/Mac_XS.sea.hqx>




############################ ORIGINAL FOLLOWS ####################################################################


NAME
    Compress::LZF - extremely leight-weight Lev-Zimpel-Free compression

SYNOPSIS
       use Compress::LZF;

       $compressed = compress $uncompressed_data;

       $original_data = decompress $compressed;

DESCRIPTION
    LZF is an extremely fast (not that much slower than a pure memcpy)
    compression algorithm. It is ideal for applications where you want to
    save *some* space but not at the cost of speed. It is ideal for
    repetitive data as well. The module is self-contained and very small (no
    large library to be pulled in). It is also free, so there should be no
    problems incoporating this module into commercial programs.

    I have no idea wether any patents in any countries apply to this
    algorithm, but at the moment it is believed that it is free from any
    patents.

FUNCTIONS
  $compressed = compress $uncompressed

    Try to compress the given string as quickly and as much as possible. In
    the worst case, the string can enlarge by 1 byte, but that should be the
    absolute exception. You can expect a 45% compression ratio on large,
    binary strings.

  $decompressed = decompress $compressed

    Uncompress the string (compressed by "compress") and return the original
    data. Decompression errors can result in either broken data (there is no
    checksum kept) or a runtime error.

SEE ALSO
    Other Compress::* modules, especially Compress::LZV1 (an older, less
    speedy module that guarentees only 1 byte overhead worst case) and
    Compress::Zlib.

    http://liblzf.plan9.de/

AUTHOR
    This perl extension and the underlying liblzf were written by Marc
    Lehmann <pcg@goof.com> (See also http://liblzf.plan9.de/).

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