Re: [Vala] Binding 7zip library ?

[Evan Nemerson <evan coeus-group com>]

On Tue, 2013-08-27 at 08:46 +0200, raum no-log org wrote:
> I had a look to libarchive... It seems libarchive 3.0 could handle 7Zip
> format (for reading) but unfortunately there is only a vapi file for
> version 2...
>
> I've read some pages about "how to generate vapi" but I didnt success...
>
> Should I try to write by hand a vapi file ?

libarchive is not GObject-based, so it's not possible to generate a vapi
automatically.  Writing it by hand is your only option.

libarchive 3 is compatible with previous versions, so there is no need
to create a new VAPI.  Just add what you need to the existing bindings.

> Thanks
>
> > On Mon, 2013-08-26 at 11:27 +0200, raum no-log org wrote:
> > > Hello,
> > >
> > > I've downloaded and build 7Zip library and I've these files compiled
> > > (under Windows using MingW32, with prefix /opt) :
> > >
> > > /src/lib7zip-1.6.5/Lib7Zip/lib7zip.a
> > > /src/lib7zip-1.6.5/Lib7Zip/lib7zip.dll
> > > /src/lib7zip-1.6.5/Lib7Zip/lib7zip.h
> > >
> > > "make install" command didn't copy these files under /opt/bin,
> > > /opt/include, /opt/library
> >
> > The 7zip SDK really designed to be embedded within your project, not
> > used as a shared library.
> >
> > > I've copied manually in the correct directory but tests programs output
> > > :
> > > # test7zip.exe
> > > initialize fail!
> > >
> > > So I think I've made a mistake somewhere... But how to test it with a
> > > vala
> > > test program ? I need to build a vapi file ? something like that ?
> >
> > Yes, you would need to create VAPI.  I looked at the 7zip SDK API quite
> > recently and I don't think creating a VAPI would be an easy task.  The
> > API is a bit of a mess.
> >
> > I'm not sure what your use case is.  If you need to read and write *.7z
> > files you might want to look at libarchive?I'm not sure whether they
> > support 7zip or not, but if they do then it would be a much easier way
> > to go since it already has a VAPI.
> >
> > If you just want to compress stuff you might want to take a look at a
> > project I've been working on called Squash [1], which does have Vala
> > bindings.  It is an abstraction layer for compression libraries (not
> > archivers?that's what libarchive is for), and it supports most of the
> > algorithms 7zip uses.
> >
> > I do plan to write a Squash plugin for the 7zip SDK eventually [2], and
> > if you really need PPMD, BCJ, or BCJ2 (Squash already supports LZMA,
> > LZMA2, bzip2, and DEFLATE) I can take a look at that sooner rather than
> > later, but keep in mind that it will not support *.7z archives.
> >
> > Also, if you're not tied to 7zip, you may want to look at FreeArc [3].
> > I don't remember if they have an API you could use or not, but the PPM
> > compression is better, and the other algorithms are great [4].  Or, if
> > all you care about is compression ratio, ZPAQ [5] (for which there is a
> > Squash plugin) is amazing.
> >
> >
> > -Evan
> >
> > [1] http://quixdb.github.io/squash/
> > [2] https://github.com/quixdb/squash/issues/31
> > [3] http://freearc.org/
> > [4] http://compressionratings.com/i_freearc.html
> > [5] http://mattmahoney.net/dc/zpaq.html