[sword-devel] Compression status

Troy A. Griffitts sword-devel@crosswire.org
Thu, 13 Jan 2000 16:36:06 -0700

	Daniel Glassey contributed working code a while back.  He did a good
job incorporating it into the framework in which he had to work.  Upon
receiving the code, I realized some fundamental flaws in the design of
the SWCompress mechanism.  These flaws have been revised and the working
version is in CVS, along with test apps in the sword/test directory.  It
allows compression types to more easily be swapped out.

	Daniel chose to use zlib instead of our LHZ compression algorythm.  I
wanted the framework to support either.  We chose LHZ because this is
what STEP uses.  We also include the algorythm in our code instead of
using external libraries.  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

	I still have not finished encorporating the SWModule drivers that
Daniel submitted into the CVS tree.  I need to make sure they work with
the new compression mechanism.

	This is the status.


Chris Little wrote:
> > > I can add that bzip2 compresses the sword modules very well but nothing
> works
> > > on the encrypted modules both tar.bz2 and tar.gz create packages that
> are
> > > somewhat larger than the originals.
> >
> > That's why we would need the compression libraries - you need to encrypt
> after compressing.
> Speaking of which.... What's the status of our compression libraries?  I
> thought I read a while back that they were very near completion.  Are they
> already or soon to be included in the CVS?  Are they going to support
> encryption?  I'm really excited about this added functionality, and so is my
> laptop's pitifully insufficient hard drive.
> --Chris