[FFmpeg-devel] [PATCH v2] avcodec/h2645_parse: refine the code for better readiablity

[Limin Wang]

On Wed, Sep 11, 2019 at 10:29:14AM -0300, James Almer wrote:
> On 9/10/2019 2:38 AM, lance.lmwang at gmail.com wrote:
> > From: Limin Wang <lance.lmwang at gmail.com>
> > 
> > Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
> > ---
> >  libavcodec/h2645_parse.c | 10 ++++------
> >  1 file changed, 4 insertions(+), 6 deletions(-)
> > 
> > diff --git a/libavcodec/h2645_parse.c b/libavcodec/h2645_parse.c
> > index 307e8643e6..f077900617 100644
> > --- a/libavcodec/h2645_parse.c
> > +++ b/libavcodec/h2645_parse.c
> > @@ -453,16 +453,15 @@ int ff_h2645_packet_split(H2645Packet *pkt, const uint8_t *buf, int length,
> >              }
> >          }
> >  
> > -        if (pkt->nals_allocated < pkt->nb_nals + 1) {
> > -            int new_size = pkt->nals_allocated + 1;
> > -            void *tmp = av_realloc_array(pkt->nals, new_size, sizeof(*pkt->nals));
> > +        if (pkt->nb_nals >= pkt->nals_allocated) {
> > +            void *tmp = av_realloc_array(pkt->nals, pkt->nals_allocated + 1, sizeof(*pkt->nals));
> >  
> >              if (!tmp)
> >                  return AVERROR(ENOMEM);
> >  
> >              pkt->nals = tmp;
> > -            memset(pkt->nals + pkt->nals_allocated, 0,
> > -                   (new_size - pkt->nals_allocated) * sizeof(*pkt->nals));
> > +            memset(pkt->nals + pkt->nals_allocated, 0, sizeof(*pkt->nals));
> > +            pkt->nals_allocated++;
> 
> The nal->skipped_bytes_pos allocation below can still fail. This counter
> shouldn't increase until all allocations have succeeded.
Yes, if the next line code use pkt->nals_allocated to get nal to allocate 
by nal->skipped_bytes_pos then it's easy understand to move the counter
until all allocation are done.


> 
> >  
> >              nal = &pkt->nals[pkt->nb_nals];
> >              nal->skipped_bytes_pos_size = 1024; // initial buffer size
> > @@ -470,7 +469,6 @@ int ff_h2645_packet_split(H2645Packet *pkt, const uint8_t *buf, int length,
> >              if (!nal->skipped_bytes_pos)
> >                  return AVERROR(ENOMEM);
> >  
> > -            pkt->nals_allocated = new_size;
> >          }
> >          nal = &pkt->nals[pkt->nb_nals];
> >  
> > 
> 
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