[FFmpeg-devel] [PATCH 1/3] Revert "bitstream: make vlc init of static tables thread safe."

[Paul B Mahol]

On 7/13/13, Michael Niedermayer <michaelni at gmx.at> wrote:
> This reverts commit 4b6869d6e0120c92253d525921f0e04361888e10.
>
> Conflicts:
>
> 	libavcodec/bitstream.c
>
> This code can cause assertion failures on artificial OOM situations

And why revert it? It can not be fixed or?

>
> Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
> ---
>  libavcodec/bitstream.c |   23 ++++++-----------------
>  1 file changed, 6 insertions(+), 17 deletions(-)
>
> diff --git a/libavcodec/bitstream.c b/libavcodec/bitstream.c
> index bbd9491..3c4d176 100644
> --- a/libavcodec/bitstream.c
> +++ b/libavcodec/bitstream.c
> @@ -272,24 +272,11 @@ int ff_init_vlc_sparse(VLC *vlc, int nb_bits, int
> nb_codes,
>
>      vlc->bits = nb_bits;
>      if (flags & INIT_VLC_USE_NEW_STATIC) {
> -        VLC dyn_vlc = *vlc;
> -
> -        if (vlc->table_size)
> +        if (vlc->table_size && vlc->table_size == vlc->table_allocated) {
>              return 0;
> -
> -        ret = ff_init_vlc_sparse(&dyn_vlc, nb_bits, nb_codes,
> -                                 bits, bits_wrap, bits_size,
> -                                 codes, codes_wrap, codes_size,
> -                                 symbols, symbols_wrap, symbols_size,
> -                                 flags & ~INIT_VLC_USE_NEW_STATIC);
> -        av_assert0(ret >= 0);
> -        av_assert0(dyn_vlc.table_size <= vlc->table_allocated);
> -        if (dyn_vlc.table_size < vlc->table_allocated)
> -            av_log(NULL, AV_LOG_ERROR, "needed %d had %d\n",
> dyn_vlc.table_size, vlc->table_allocated);
> -        memcpy(vlc->table, dyn_vlc.table, dyn_vlc.table_size *
> sizeof(*vlc->table));
> -        vlc->table_size = dyn_vlc.table_size;
> -        ff_free_vlc(&dyn_vlc);
> -        return 0;
> +        } else if(vlc->table_size) {
> +            abort(); // fatal error, we are called on a partially
> initialized table
> +        }
>      } else {
>          vlc->table           = NULL;
>          vlc->table_allocated = 0;
> @@ -343,6 +330,8 @@ int ff_init_vlc_sparse(VLC *vlc, int nb_bits, int
> nb_codes,
>          av_freep(&vlc->table);
>          return ret;
>      }
> +    if((flags & INIT_VLC_USE_NEW_STATIC) && vlc->table_size !=
> vlc->table_allocated)
> +        av_log(NULL, AV_LOG_ERROR, "needed %d had %d\n", vlc->table_size,
> vlc->table_allocated);
>      return 0;
>  }
>
> --
> 1.7.9.5
>
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