[vlc-devel] [PATCH] gme: fixed out-of-memory/out-of-range tests

[Piotr Fusik]

Dnia 2012-03-23 19:08 Rémi Denis-Courmont napisał(a):

>> >> -            int seek = (sys->titlev[sys->track_id]->i_length / 1000) 
*
>> >> pos; -            if (seek > INT_MAX || gme_seek (sys->emu, seek))
>> >> +            double seek = (sys->titlev[sys->track_id]->i_length / 
1000)
>> 
>> *
>> 
>> >> pos;
>> >> +            if (seek > INT_MAX || gme_seek (sys->emu, (int) seek))
>> >
>> >So signed overflow is undefined. Unsigned would be enough and avoid 
going
>> 
>> to
>> 
>> >FPU...
>> 
>> Correct me if I'm wrong, but I thought double->unsigned conversion is 
only
>> defined within the range of unsigned?
>
>Yeah? So?
>
>I mean, we do care about not crashing or exhibiting undefined behaviour. We 
>don't care about not playing corrupt or overly long files correctly.
>
>Unsigned should be enough to protect against undefined behaviour, even if 
it 
>might cause integer overflow, no?

Not sure if we understand well. :)

an_int > INT_MAX makes no sense. You can:
a. replace it with a_double > INT_MAX as I did
b. replace it with an_int < 0
c. remove it
I don't see how an unsigned would help here.

Piotr