[systemd-devel] [PATCH] prioq: avoid to swap item index

[Lennart Poettering]

On Mon, 16.12.13 04:48, Lennart Poettering (lennart at poettering.net) wrote:

> 
> On Mon, 16.12.13 11:03, Chengwei Yang (chengwei.yang at intel.com) wrote:
> 
> > the swap() operation of prioq which in fact only swap item's data but
> > keep idx untouched. However, current implement does first swap the idx
> > and then swap back again.
> 
> Sorry, I do understand? Can you elaborate, please? Is this supposed to
         ^^^^wanted to say: I do *not* understand...
> be a bug fix or an optimization?
> 
> > ---
> >  src/shared/prioq.c |   10 ----------
> >  1 file changed, 10 deletions(-)
> > 
> > diff --git a/src/shared/prioq.c b/src/shared/prioq.c
> > index 8af4c51..ef99c47 100644
> > --- a/src/shared/prioq.c
> > +++ b/src/shared/prioq.c
> > @@ -68,7 +68,6 @@ int prioq_ensure_allocated(Prioq **q, compare_func_t compare_func) {
> >  
> >  static void swap(Prioq *q, unsigned j, unsigned k) {
> >          void *saved_data;
> > -        unsigned *saved_idx;
> >  
> >          assert(q);
> >          assert(j < q->n_items);
> > @@ -78,17 +77,8 @@ static void swap(Prioq *q, unsigned j, unsigned k) {
> >          assert(!q->items[k].idx || *(q->items[k].idx) == k);
> >  
> >          saved_data = q->items[j].data;
> > -        saved_idx = q->items[j].idx;
> >          q->items[j].data = q->items[k].data;
> > -        q->items[j].idx = q->items[k].idx;
> >          q->items[k].data = saved_data;
> > -        q->items[k].idx = saved_idx;
> > -
> > -        if (q->items[j].idx)
> > -                *q->items[j].idx = j;
> > -
> > -        if (q->items[k].idx)
> > -                *q->items[k].idx = k;
> >  }
> >  
> >  static unsigned shuffle_up(Prioq *q, unsigned idx) {
> 
> 
> Lennart
> 


Lennart

-- 
Lennart Poettering, Red Hat