[U-Boot] [PATCH v3 3/7] dfu: DFU backend implementation

Marek Vasut
2012-08-04T07:47:34Z

Dear Mike Frysinger,

> On Thursday 02 August 2012 09:55:24 Lukasz Majewski wrote:
> > Dear Mike Frysinger,
> >
> > > On Tuesday 31 July 2012 02:36:59 Lukasz Majewski wrote:
> > > > +{
> > > > + int i = 0;
> > > > +
> > > > + for (; *s; s++)
> > > > + if (*s == ';')
> > > > + i++;
> > > > +
> > > > + return ++i;
> > > > +}
> >
> > In this function I count how many times the ';' separator appears.
>
> well, to be more specific, i think it's counting the number of elements if
> you were to split on ';'. so if there was one ';', this would return 2.
> but you're correct of course that my suggested replacement is not
> equivalent.
>
> > > > +int dfu_config_entities(char *env, char *interface, int num)
> > > > +{
> > > > + struct dfu_entity *dfu;
> > > > + int i, ret;
> > > > + char *s;
> > > > +
> > > > + dfu_alt_num = dfu_find_alt_num(env);
> > > > + debug("%s: dfu_alt_num=%d\n", __func__, dfu_alt_num);
> > > > +
> > > > + for (i = 0; i < dfu_alt_num; i++) {
> > > > + dfu = calloc(sizeof(struct dfu_entity), 1);
> > >
> > > seems like you can do this in a single call outside of the for loop:
> > > dfu = calloc(sizeof(*dfu), dfu_alt_num);
> > > if (!dfu)
> > >
> > > return -1;
> > >
> > > for (i = 0; i < dfu_alt_num; i++) {
> > >
> > > s = strsep(&env, ";");
> > > ret = dfu_fill_entity(&dfu[i], s, i, interface, num);
> > > if (ret)
> > >
> > > return -1;
> > >
> > > list_add_tail(&dfu[i].list, &dfu_list);
> > >
> > > }
> >
> > I'd prefer to leave it as it is (since IMHO is more readable) with the
>
> > addition of following code:
> it might be more slightly more readable, but doing a single function call
> results in better runtime performance

Doesn't the compiler optimize it as it sees fit?

Best regards,
Marek Vasut