AmiUpdate unarchiver question

Maybe someone knows...

Taken from AmiUpdate online manual
Quote:

I can't see how AU does that.
Is it using it's own unarchive code?
Does it fall back to xad/xpk (if installed)?
Or even tools like "lha" and "zip" (if installed)?

What i like to know is
1) would it make sense to switch to .xz (zip based afaik) for OS4Depot releases (ScummVM is starting to grow big) since it features way better crunching figures than .lha and .zip.
2) Does "every" AmigaOS4 user has access to decrunchers supporting the .xz format (i know there are some decrunchers on OS4Depot.net) or only those that have bought Enhancer? (Archiver can do .xz through it's "compress files" feature)

Thank you

AmiUpdate uses the xadmaster.library to unpack archives, so as long as you choose a supported archive format, there shouldn't be a problem.

Simon

@Rigo

Thank you very much

It's seen as zip, so, good to go

@Raziel

XZ isn't seen as Zip, it's a single file archive format. There is a XAD plug-in for XZ (I wrote it) but not everybody will have it. Although I'm not sure how you're compressing a multi file archive with XZ, you'd need to put it into an uncompressed LhA or something first.

I think Zip can use LZMA compression (similar to XZ), but the built-in Zip plug-in for XAD can't decompress it.

@Chris

I see, not sure how Archiver does it.

Probably just stores the files first and then .xz over it?

@Raziel

The PKWARE zip archive format supports several compression methods including zlib (AKA deflate), bzip2, lzma, xz and zstd.

Traditionally zip archives only use zlib compression though, and zip archives that use more advanced methods are generally referred to as zipx archives even though the file format is the same.

The xadmaster.library zip client supports only zlib method but Archiver has it's own zip client that makes use of zip.library which has support for other compression methods, as well as being able to create/modify zip archives and not just read from them.

@salass00

Just tried with a multi-file .xz archive created with Archiver.

xadUnFile is not able to handle those.
First it reports corrupt data where there is none, then it goes into decunching a random file with a hillarious high byte count where the file 115 KB.

btw, that last file is not even part of the package, so...

Ok then, back to using it solely for my personal backups...

Thank you all

@salass00

I was considering making a XAD Zip client using zip.library but it's a way down the list.

In the meantime, my libarchive based one should do the trick although it's a bit unstable.

@Raziel

Given XZ provides superior compression is why I used it in my X1Boot loader. Which was easy enough since I can embed it in the code and not reply on anything external. It's even better for PPC code since it has a PPC filter to optimise PPC binary compression.

@Hypex

Tbh it's probably better to use 7-Zip with the LZMA2 (same as XZ) compression. You don't then get the confusion with unsupported Zip files.

@Chris

I used XZ as I found an embedded XZ unpacker I could easily compile in. In fact I can compile it from OS4 even though the code is generic and produces an OF binary. But my boot loader handles all the unpacking. The user doesn't need to concern themselves with any format as it's all handled by the manager that compresses kernels. Though it does only accept raw, GZip and XZ. First two are used in X1000 kernels.

@Hypex

My comment was supposed to be aimed at Raziel 🙂

@Chris

Oops.

@Chris
@Hypex

Nah, it's fine, keep playing

I'm lazy, i like all-in-one stuff (preferably with plugins, where it is easy to switch out certain parts).

iirc 7-zip is a stand-alone program and i'd like to move away from those.

Unarc or Archiver can do all the stuff i need with some mouse clicks with a nice GUI...so, i'll stick to those

Suggestions welcome, of course