On 2012-11-14 Jack Duston wrote:
> Given time involved in compressing and the quantity of data, I am
> hesitant to use the 5.1.2alpha code.
> I am paying attention when your web page says it should be considered
> unstable!
It is good to be cautious with unstable releases.
There are people using 5.1.2alpha and I haven't got bug reports. I'm
not aware of any data corruption bugs. So in this particular case I
think it's not too dangerous to use the development version. You get
threading in addition to the --block-size option.
Another option is to use for example pixz:
https://github.com/vasi/pixz
XZ Utils 5.1.2alpha and pixz both can create a single .xz stream that
contains many blocks, and thus make random access reading possible. I
haven't used truly pixz myself so I cannot say anything else about it.
> I see in the Release Notes that the "--block-size" option was added
> to the April, 2011 alpha release, and we are fast approaching 2013.
> I don't know how complex the code change is, or if it goes against
> your release policy, but would you consider back-porting the
> "--block-size" option to a 5.0.5 Stable Release? I surely can't be
> the only one who would love to make use of the option.
I don't like to add any new features in a stable branch. I'm doing this
to (hopefully) make it easier for downstream distributions to include
bug fixes in stable distributions where the distro maintainers want
only bug/security fixes to minimize the risk of new bugs.
Adding --block-size isn't a huge patch, but in this particular case I
think it should be safe to try 5.1.2alpha.
> My ultimate end is to incorporate the XZ library or Embedded into our
> application to search and read the compressed files directly.
> In any case, thanks again for all the work you've put into xz, I will
> be compressing with your utility either way.
Random access can be done with liblzma, but the provided APIs are too
low level to make it nice to use. See src/xz/list.c in XZ Utils what
kind of things you need to do. There is an old plan to have a file I/O
library that makes things easy for the most common use cases. I even
started writing it long ago but didn't get very far.
There is random access support in XZ for Java, but I guess it doesn't
help you.
--
Lasse Collin | IRC: Larhzu @ IRCnet & Freenode
