[FFmpeg-devel] [PATCH 1/2] avformat/oggdec: Factor buffer reallocation out

Michael Niedermayer michael at niedermayer.cc
Fri May 1 22:07:10 EEST 2020


On Fri, May 01, 2020 at 06:47:54PM +0200, Lynne wrote:
> May 1, 2020, 14:16 by michael at niedermayer.cc:
> 
> > Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> > ---
> >  libavformat/oggdec.c | 25 +++++++++++++++++--------
> >  1 file changed, 17 insertions(+), 8 deletions(-)
> >
> > diff --git a/libavformat/oggdec.c b/libavformat/oggdec.c
> > index c591bafddd..a9034ea61c 100644
> > --- a/libavformat/oggdec.c
> > +++ b/libavformat/oggdec.c
> > @@ -297,6 +297,20 @@ static int data_packets_seen(const struct ogg *ogg)
> >  return 0;
> >  }
> >  
> > +static int buf_realloc(struct ogg_stream *os, int size)
> > +{
> > +    /* Even if invalid guarantee there's enough memory to read the page */
> > +    if (os->bufsize - os->bufpos < size) {
> > +        uint8_t *nb = av_realloc(os->buf, 2*os->bufsize + AV_INPUT_BUFFER_PADDING_SIZE);
> > +        if (!nb)
> > +            return AVERROR(ENOMEM);
> > +        os->buf = nb;
> > +        os->bufsize *= 2;
> > +    }
> >
> 
> Looking at the code, this is just av_fast_realloc.
> You could change it to that, or you could just allocate MAX_PAGE_SIZE at the start and never reallocate. Its only 65k.
> Up to you, feel free to commit whatever you choose.

The code already allocates 65k at the start
so ill apply this so this bug/regression is fixed, we can then change it
dont want to leave this bug open until we found the perfect solution

thx

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Old school: Use the lowest level language in which you can solve the problem
            conveniently.
New school: Use the highest level language in which the latest supercomputer
            can solve the problem without the user falling asleep waiting.
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