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

[Lennart Poettering]

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
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 Poettering, Red Hat