xz decompressor

[daurnimator]

xz is a lossless compression program and file format which incorporates the LZMA/LZMA2 compression algorithms.

Useful for:

• reading compressed debug info (external and compressed debug info #2300)
• potentially the package manager (package manager #943)
• potentially the glibc ABI info (support glibc version as part of the target #2847 (comment))

Related to:

• DEFLATE implementation (deflate implementation in standard library #213)

[shawnl]

xz is a nice algorithm, but zstd got close while having many other use-cases for fast compression too. This is because zstd uses finite state entropy, which is quite new.

[daurnimator]

Although zstd is preferred these days; we still need XZ to support e.g. compressed debug info https://sourceware.org/gdb/onlinedocs/gdb/MiniDebugInfo.html, unless gdb and other common utilities are changing any time soon?

[shawnl]

@daurnimator note that LZMA is similar, but not the same as XZ (they are both supported by liblzma2). (LZMA was the beta version, that because become so widely used, the final version got a different name.)

I really don't see why we can't just build the C version, and use that.

[data-man]

lzma in ofelas/zigtest

[daurnimator]

@ofelas would you like to make that into a PR to the standard library?

[shawnl]

And his response should be to add a license to his repository. GitHub has a good page on choosing a license (I this in this case only BSD-2/3 or MIT would be acceptable) which I would link to if I was connected to internet. El jue., 26 sept. 2019 8:19, Vesa Kaihlavirta <notifications@github.com> escribió:

…

Since that code/rope doesn't have any license information, @ofelas <https://github.com/ofelas> should probably be contacted whether it's ok to just add that to Zig. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#2851?email_source=notifications&email_token=AAD4W4SYU7NCJ2HCDOI7T73QLSSEXA5CNFSM4H65FTA2YY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOD7VLSOI#issuecomment-535476537>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAD4W4UVLWFFQQU5CZCK3SDQLSSEXANCNFSM4H65FTAQ> .

[ofelas]

I added a LICENSE file (MIT) as the original Rust code has in case anyone wants to use said code.
Unfortunately, I have little or no time to spend on this at the moment.