[FFmpeg-devel] [PATCH 1/7] ffprobe: Change string_validation to int, its accessed via AVOption as int

[Michael Niedermayer]

On Wed, Feb 04, 2015 at 03:23:59PM +0100, Michael Niedermayer wrote:
> On Wed, Feb 04, 2015 at 12:34:53PM +0100, Stefano Sabatini wrote:
> > On date Monday 2015-02-02 23:22:09 +0100, Michael Niedermayer encoded:
> > > Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
> > > ---
> > >  ffprobe.c |    2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/ffprobe.c b/ffprobe.c
> > > index d352bb6b..30f9cba 100644
> > > --- a/ffprobe.c
> > > +++ b/ffprobe.c
> > > @@ -338,7 +338,7 @@ struct WriterContext {
> > >      unsigned int nb_section_frame;  ///< number of the frame  section in case we are in "packets_and_frames" section
> > >      unsigned int nb_section_packet_frame; ///< nb_section_packet or nb_section_frame according if is_packets_and_frames
> > >  
> > > -    StringValidation string_validation;
> > > +    int string_validation;
> > >      char *string_validation_replacement;
> > >      unsigned int string_validation_utf8_flags;
> > >  };
> > 
> > What's the problem with the enum and av_opt()?
> > 
> > Enums help with debugging.
> 
> the enum might be a different data type than int, it might have
> a different sizeof() than sizeof(int), av_opt accessing it could
> fail.
> Iam not aware of a real platform where this actually happens but that
> could be my lack of knowledge of how enums are defined in the various
> ABIs

If people prefer to keep using enums for the fields then it should be
possible to avoid this problem also by introducing a dummy value
in the affected enums which is too large for uint16 but fits in int32
this would force the enum to use int as data type.
This might require accesses in AVOption to use AV_R/WN32 to avoid
theoretical strict aliassing issues
also it leaves the even more theoretical issue that a platform could
use int64_t as enum type or some more weird in between type

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Many that live deserve death. And some that die deserve life. Can you give
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even the very wise cannot see all ends. -- Gandalf
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