[sword-devel] Compression status

Daniel Glassey sword-devel@crosswire.org
Fri, 14 Jan 2000 12:05:21 -0000


On 13 Jan 00, at 16:36, Troy A. Griffitts sent forth the message:

>  Daniel chose to use zlib instead of our LHZ compression algorythm.  I
> wanted the framework to support either.  

Definitely a good idea, no need to be restrictive.

> We chose LHZ because this is
> what STEP uses.  We also include the algorythm in our code instead of
> using external libraries.  

Just out of curiosity, is STEP still around? (www.bsisg.com isn't 
working right now)

> Before adding the zlib compressor, I would
> like to investigate the usability on Windows and consider whether or
> not we should include the algorythm in our code instead of calling
> external libraries.

http://www.cdrom.com/pub/infozip/zlib/
It's very usable, compilable with all the win compilers.

The advantage of using an external library is that you don't have to 
keep up with the modifications. On systems which should have the 
library already like linux, you can just use the shared library instead 
of compiling the code into your library.
It would be worth keeping the zlib code in CVS though so that 
everyone has the source.

I guess a decision will have to made about whether to use zlib, LHZ, 
or bzip or another for the main distribution of modules though. I 
guess the issues are going to be size of compressed module and 
decompression speed, but I don't yet know which will be best. All 
should definitely be supported though.

btw after the current thread on compression stuff I don't think I 
did encryption/compression (and decry/decomp) in the right order so 
that will need fixed.

Regards,
	Daniel