On Mon, 24.11.14 13:31, Jan Synacek (jsyna...@redhat.com) wrote:
> Lennart Poettering <lenn...@poettering.net> writes:
> > On Fri, 14.11.14 12:42, Jan Synacek (jsyna...@redhat.com) wrote:
> >> + if (look_for == LAYOUTS) {
> >> + Set *s;
> >> + char *k;
> >> + Iterator i;
> >> + /* XXX: Is there a better way to sort Hashmap keys? */
> >> + _cleanup_strv_free_ char **tmp = NULL;
> >> +
> >> + HASHMAP_FOREACH_KEY(s, k, keymap->x11_layouts, i)
> >> + if (strv_extend(&tmp, k) < 0)
> >> + (void) log_oom();
> >
> > There's hashmap_get_strv() for cases like this.
>
> I need keys, not values. I didn't find any hashmap_get_strv() equivalent
> for keys.
Maybe add it then? I think this might become useful even beyond the
kbd mapping part one day.
> > Also, please neer invoke strv_extend() when appending to unbounded
> > arrays. It's slow!
>
> What is a preffered way to extend a strv? In this case, I know the final
> size, so it the array could manually be copied. I don't think that
> that's very nice, though.
Best case: you know the precise size of the array in the end. In that
case, simply use realloc()/realloc_multiply() to allocate the right
sized array, fill it in, done.
If you don#t know the size, but you guess that it might be quite a few
entries in there in the end and you might be adding a good chunk of
them, please use greedy_realloc(). It grows the array exponentially,
which is very beneficial performance-wise.
If you don't know the size, but you are pretty sure that it will never
gro to more than 10 entries or so, and that you are just going to
add a couple of them, then strv_extend()/strv_push()/strv_consume()
are OK.
> > Humm, when clearing up hashmaps please just write a loop that steals
> > the first entry, free it and then repeat. Iterating through a hashmap
> > while deleting its entries is unnecessary...
>
> I need to free its entries *and* keys. I didn't find any function that I
> could use for that, apart from hashmap_free_free(), which crashes in
> my case.
while ((k = hashmap_first_key())) {
v = hashmap_steal_first();
free(v);
free(k);
}
Lennart
--
Lennart Poettering, Red Hat
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