Hi,
On Tue, 31 Mar 2009, Christian Couder wrote:
> Le lundi 30 mars 2009, Johannes Schindelin a écrit :
>
> > On Mon, 30 Mar 2009, Christian Couder wrote:
> > > Le jeudi 26 mars 2009, Junio C Hamano a écrit :
> > > >
> > > > I've learned to suspect without reading a qsort() callback that
> > > > does not derefence its arguments. Is this doing the right thing?
> > >
> > > I think so.
> >
> > I suspect something much worse: you are trying to build a list of
> > sha1s of commits that need to be skipped, later to look up every
> > commit via binary search.
> >
> > But it has been proven a lot of times that using a hash set is
> > superior to that approach, and even better: we already have the
> > framework in place in the form of struct decorate.
>
> I had a look, and "struct decorate" can be used to store objects, but I
> want to store only sha1s.
No, you want to _look up_ sha1s. And struct decorate is not about storing
objects, but to attach things to objects. From decorate.h:
struct object_decoration {
const struct object *base;
void *decoration;
};
So, if you just do
struct decoration all_the_sha1s;
...
add_decoration(&all_the_sha1s, &commit->object, sha1);
you can look up the sha1 much more efficiently than with binary searches
like this:
unsigned char *sha1 = lookup_decoration(&all_the_sha1s,
&commit->object);
Ciao,
Dscho
