[FFmpeg-devel] [PATCH 1/3] lavf/srtdec: simplify start/end computation.

[Clément Bœsch]

On Sun, Oct 21, 2012 at 10:17:29AM +0200, Nicolas George wrote:
> Le decadi 30 vendémiaire, an CCXXI, Clément Bœsch a écrit :
> > Also fix potential overflow (CID733778)
> > ---
> >  libavformat/srtdec.c | 17 +++++++----------
> >  1 file changed, 7 insertions(+), 10 deletions(-)
> > 
> > diff --git a/libavformat/srtdec.c b/libavformat/srtdec.c
> > index a66ced3..056165e 100644
> > --- a/libavformat/srtdec.c
> > +++ b/libavformat/srtdec.c
> > @@ -53,19 +53,16 @@ static int srt_read_header(AVFormatContext *s)
> >  
> >  static int64_t get_pts(const char *buf, int *duration)
> >  {
> > -    int i, hour, min, sec, hsec;
> > -    int he, me, se, mse;
> > +    int i;
> >  
> >      for (i=0; i<2; i++) {
> > -        int64_t start, end;
> > +        int hh1, mm1, ss1, ms1;
> > +        int hh2, mm2, ss2, ms2;
> >          if (sscanf(buf, "%d:%2d:%2d%*1[,.]%3d --> %d:%2d:%2d%*1[,.]%3d",
> > -                   &hour, &min, &sec, &hsec, &he, &me, &se, &mse) == 8) {
> > -            min += 60*hour;
> > -            sec += 60*min;
> > -            start = sec*1000+hsec;
> > -            me += 60*he;
> > -            se += 60*me;
> > -            end = se*1000+mse;
> > +                   &hh1, &mm1, &ss1, &ms1,
> > +                   &hh2, &mm2, &ss2, &ms2) == 8) {
> > +            int64_t start = (hh1*3600LL + mm1*60LL + ss1) * 1000LL + ms1;
> > +            int64_t end   = (hh2*3600LL + mm2*60LL + ss2) * 1000LL + ms2;
> >              *duration = end - start;
> >              return start;
> >          }
> 
> It looks better, thanks.
> 
> I do not like the type mismatch: there is no guarantee that long long is the
> same as int64_t.

I thought the long long type was guaranteed to be at least 64 bits by the
c99 standard…

>                   Maybe you could write:
> 
> hh1 * (int64_t)3600 + ...
> 

looks ugly :(

Also we use the LL in various places for that purpose.

[...]

-- 
Clément B.
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