Re: [Vala] How to use the ZLib bindings?

[Yu Feng <rainwoodman gmail com>]

Hi,

On Tue, 2009-11-10 at 09:10 +0100, pHilipp Zabel wrote:
> Hi Yu,

> I still maintain that strm.next_in / strm.next_out cannot be owned
> arrays because the call to strm.inflate changes the pointers
> themselves. The same program compiles unchanged when I remove the weak
> keywords again, but it fails when trying to destroy the buffers:
> *** glibc detected *** ./zlibtest: munmap_chunk(): invalid pointer:
> 0x000000000210b500 ***

I didn't know about this behavior. Could you kindly post me a copy of
the CCode for zlibtest? I'd like to do some research on it and get this
point clear.

> The '->' argument doesn't apply here - uchar* vs uchar[], no structs involved.
> But I agree that a single weak uchar[] is more Valaish than a uchar* and an int.

> The initial assignment is more compact this way:
>       strm.next_out = buf_out;
> vs
>       strm.next_out = buf_out;
>       strm.avail_out = buf_in.length;
> And I have to replace strm.avail_out with stream.next_out.length.
> Other than that,
> it's the same. So should we change that back (to weak uchar[]s)?
I definitely prefer using weak uchar[]s, as the field is an array but a
pointer. 

If keeping the vapi similar to the original API is important, then you
may consider add the avail_out field in the struct declaration and write
a comment, stating that it is the same as next_out.length, and the mere
purpose of that field is to keep the API consistent; or use
(no_array_length=true) CCode attribute.

PS: To get your patches applied, you have to let vapi maintaine know
about your patch. See [http://live.gnome.org/Vala/BindingsStatus]. 



Yu

> Thanks for having a look at this.
>
> regards
> Philipp