[FFmpeg-devel] [PATCH 1/6] avformat/format: add av_demuxer_find_by_ext

Anton Khirnov anton at khirnov.net
Tue Feb 18 16:28:48 EET 2020

Quoting Gyan Doshi (2020-02-01 06:15:30)
> On 31-01-2020 10:41 pm, Andreas Rheinhardt wrote:
> > Gyan Doshi:
> >> Allows selecting demuxer by extension which are more widely recognized
> >> by users.
> >>
> >> Conditional cast added since this function will usually be called after
> >> av_find_input_format, and so matches its return type.
> > That's not a good point. av_demuxer_find_by_ext() already always
> > returns const AVInputFormat *, so you casting the const away when
> > returning is pointless. Furthermore, any caller that wants to use this
> > new function can simply use a pointer to const AVInputFormat to work
> > with both av_find_input_format() and av_demuxer_find_by_ext(). And
> > after all, adding const makes the code more future-proof
> > (av_find_input_format() will return const AVInputFormat * after the
> > next major bump).
> Ok, I don't think I should add const to the pointers at the receiving 
> end (fftools) since they are global variables and may not be acceptable 
> as const. So I'll cast away the const when receiving and remove the 
> conditional cast.

Why not? Nothing can conceivably modify the content of those structs, so
simply adding const to all their uses should work.

Anton Khirnov

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