R devel - Feb 2010 - Fix for incorrect use of restrict in xz third party code

Hello,

the included XZ Utils source code contains an incorrect use of the
restrict keyword. This leads to data corruption under certain
circumstances. For a short discussion of the problem see

  http://sourceforge.net/projects/lzmautils/forums/forum/708858/topic/3306733

This was fixed in the XZ Utils git repository in commit 

  commit 49cfc8d392cf535f8dd10233225b1fc726fec9ef
  Author: Lasse Collin <lasse.collin at tukaani.org>
  Date:   Tue Sep 15 21:07:23 2009 +0300

    Fix incorrect use of "restrict".

Since then, there has not been a proper release of the XZ Utils so I
have applied said patch to the sources included in R and added a note
to the R_changes file in the src/extra/xz/ directory detailing the
changes.

This 'bug' is only triggered if the Intel C or gcc 4.4 is used to
compile R and the included liblzma is used instead of a system wide
one, so it might not be worth the trouble of patching the sources
instead of waiting for a new release. If anyone wants to apply a fix,
I have prepared a patch with all the changes which can be found here

  http://www.statistik.tu-dortmund.de/~olafm/temp/xz_restrict.patch

Cheers,
Olaf Mersmann

On Sat, 20 Feb 2010, Olaf Mersmann wrote:
> Hello,
>
> the included XZ Utils source code contains an incorrect use of the
> restrict keyword. This leads to data corruption under certain
> circumstances. For a short discussion of the problem see
>
> 
http://sourceforge.net/projects/lzmautils/forums/forum/708858/topic/3306733
>
> This was fixed in the XZ Utils git repository in commit
>
>  commit 49cfc8d392cf535f8dd10233225b1fc726fec9ef
>  Author: Lasse Collin <lasse.collin at tukaani.org>
>  Date:   Tue Sep 15 21:07:23 2009 +0300
>
>    Fix incorrect use of "restrict".
>
> Since then, there has not been a proper release of the XZ Utils so I
> have applied said patch to the sources included in R and added a note
> to the R_changes file in the src/extra/xz/ directory detailing the
> changes.
>
> This 'bug' is only triggered if the Intel C or gcc 4.4 is used to
> compile R and the included liblzma is used instead of a system wide
> one, so it might not be worth the trouble of patching the sources
> instead of waiting for a new release. If anyone wants to apply a fix,
> I have prepared a patch with all the changes which can be found here
>
>  http://www.statistik.tu-dortmund.de/~olafm/temp/xz_restrict.patch
We had been waiting for xz 5.000, but decided to go with 4.999 
for R 2.10.0 as it was so long a-coming -- and are still waiting.

We do use the included sources on several platforms, and with gcc 
4.4.4 on 64-bit Windows, so I will patch this, thank you.
>
> Cheers,
> Olaf Mersmann
-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595