Re: [PATCH] add pkzip support for gzio

[Robert Millan <rmh@aybabtu.com>]

On Mon, Aug 11, 2008 at 07:22:53PM +0200, Marco Gerards wrote:
> Hi,
> 
> "y.volta" <y.volta@gmail.com> writes:
> 
> >     i've made a little patch for pkziped ( deflate mode ) file. by
> > using this, we can have both gunzip and pkunzip supported: they have
> > only header different with the same file. ;-)
> >
> >     please note, if your file is too small, pkzip will not compress it
> > but store the orginal data to the output file.
> 
> Isn't this patented?

According to Wikipedia [1], the usual compression algorithm in ZIPs is the
deflate, same as gzip.  I believe older variants use the LZW algorithm, but
the patents [2] for these have expired (at least in the US), and we happen
to be using it already in our LZMA (and LZO?) code.

[1] http://en.wikipedia.org/wiki/ZIP_(file_format)
[2] http://en.wikipedia.org/wiki/LZW#Patents

-- 
Robert Millan

  The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and
  how) you may access your data; but nobody's threatening your freedom: we
  still allow you to remove your data and not access it at all."