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

[Nicolas George]

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. Maybe you could write:

hh1 * (int64_t)3600 + ...

the other computations will automatically be upgraded to int64_t to
accompdate the first one.

Regards,

-- 
  Nicolas George
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