[FFmpeg-devel] [PATCH 1/4] fftools/cmdutils: Fix undefined 1 << 31

[Andreas Rheinhardt]

Michael Niedermayer:
> On Thu, Nov 18, 2021 at 10:07:36AM +0100, Andreas Rheinhardt wrote:
>> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
>> ---
>>  fftools/cmdutils.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/fftools/cmdutils.c b/fftools/cmdutils.c
>> index 594eeef379..f80c361eba 100644
>> --- a/fftools/cmdutils.c
>> +++ b/fftools/cmdutils.c
>> @@ -1823,7 +1823,7 @@ int show_sample_fmts(void *optctx, const char *opt, const char *arg)
>>  int show_dispositions(void *optctx, const char *opt, const char *arg)
>>  {
>>      for (int i = 0; i < 32; i++) {
>> -        const char *str = av_disposition_to_string(1 << i);
>> +        const char *str = av_disposition_to_string(1U << i);
> 
> is it intended to have 1U<<31 cast to int and then checked as in
>     if (disposition <= 0)
>         return NULL;
> 
>  ?
>  

I agree that the types here (and also in ff_ctz (the relevant GCC
builtins use unsigned types) are unfortunate and AVStream.disposition as
well as the other types involved here should be unsigned. Shall I change
av_disposition_to_string to unsigned and schedule AVStream.disposition
to unsigned on the next bump? Or shall I just use "i < 31" above?

- Andreas