[FFmpeg-devel] [PATCH] rmdec: avoid leaving st unitialized

[Ronald S. Bultje]

Hi,

On Mon, Jun 7, 2010 at 12:32 AM, Kostya <kostya.shishkov at gmail.com> wrote:
> On Sun, Jun 06, 2010 at 03:33:03PM -0400, Ronald S. Bultje wrote:
>> On Sun, Jun 6, 2010 at 2:45 PM, Reimar D?ffinger
>> <Reimar.Doeffinger at gmx.de> wrote:
>> > On Sun, Jun 06, 2010 at 01:03:20PM -0400, Ronald S. Bultje wrote:
>> >> On Sun, Jun 6, 2010 at 6:57 AM, Reimar D?ffinger
>> >> <Reimar.Doeffinger at gmx.de> wrote:
>> >> > this fixes a warning with my gcc version, and I think it even fixes a bug:
>> >> > Index: rmdec.c
>> >> > ===================================================================
>> >> > --- rmdec.c ? ? (revision 23501)
>> >> > +++ rmdec.c ? ? (working copy)
>> >> > @@ -843,7 +844,7 @@
>> >> > ? ? ? ? ? ? ? ? pos = url_ftell(s->pb);
>> >> > ? ? ? ? ? ? } else {
>> >> > ? ? ? ? ? ? ? ? len=sync(s, &timestamp, &flags, &i, &pos);
>> >> > - ? ? ? ? ? ? ? ?if (len > 0)
>> >> > + ? ? ? ? ? ? ? ?if (len >= 0)
>> >> > ? ? ? ? ? ? ? ? ? ? st = s->streams[i];
>> >> > ? ? ? ? ? ? }
>> >> >
>> >> >
>> >> > The next line below this reads:
>> >> > ? ? ? ? ? ?if(len<0 || url_feof(s->pb))
>> >> > ? ? ? ? ? ? ? ?return AVERROR(EIO);
>> >> > so >= 0 fits with this condition, and other places treat a 0 value
>> >> > from "sync" as ok.
>> >>
>> >> sync() can not return zero (I've looked at this a couple of times in
>> >> the past because the gcc warning annoyed me at some point). So the
>> >> patch silences a warning but in reality, it doesn't do anything.
>> >
>> > ok, no bug, but that still leaves a compiler warning and that there's
>> > no point to treat 0 once this way once the other way...
>> > And if you "looked at this a couple of times" there's also obviously
>> > the point that it obviously wastes developer time the way it is now.
>>
>> It's like tossing a coin, shall we treat 0 as error or as success?
>> :-). I'd say error, but please then document that in reality this will
>> never happen and that it's just there to silence a compiler warning
>> (or so). OK with you Kostya?
>
> Yes but maybe we can rid of that condition completely then?

Probably.

Ronald