use_xz?

[Anders F Björklund]

Ryan Schmidt wrote:

> On Aug 8, 2009, at 14:30, Vincent Lefevre wrote:
>
>> Does MacPorts have a use_xz variable? Some tarballs are now  
>> distributed
>> in both gz and xz compression format, and xz is significantly smaller
>> than gz. For instance, for the coreutils 7.4:
>>
>>   .tar.gz   9.3 MB
>>   .tar.xz   3.9 MB
>
> No, I had not heard of xz until you mentioned it here. It can be  
> added.

XZ is the new version of LZMA (from 7-zip), which might be more  
familiar.

There is no major difference in general compression between the two  
formats,
the changes are with file magic and checksums and multithreading and  
so on.

It is slow to compress but fast to expand (2-3 times faster than bzip2),
which is why it (LZMA compression) is popular for software  
distribution...

MacPorts has support for creating XZ archives (.txz) and packages (rpm5)

> But it looks like there is only an xz-devel port for version  
> 4.999.8beta; no stable version available. They also state they  
> prefer users to build the latest version in git rather than use the  
> beta. Perhaps we should wait until their development cycle slows  
> down a bit, a stable version is released and an xz port is created  
> before promoting the use of these archives? From their homepage it  
> looks like the .xv format was only stabilized in version  
> 4.999.7beta from December 2008, assuming they don't change their  
> mind and change the format again.

The format is released, it is the code that isn't. You can still  
use .lzma
if you don't trust the .xz format, the XZ tools can expand .lzma as  
well.

Slackware Linux have changed all their packages from .tgz to .txz  
already,
and Fedora 12 are recompressing all packages with XZ instead of old  
Gzip.

--anders