[FFmpeg-devel] [PATCH 3/3] avformat/format: av_register_output_format() and av_register_intput_format() that work in O(1) time

[Stefano Sabatini]

On date Sunday 2013-12-08 03:55:23 +0100, Michael Niedermayer encoded:
> Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
> ---
>  libavformat/format.c |    9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/libavformat/format.c b/libavformat/format.c
> index 36c0131..95060f3 100644
> --- a/libavformat/format.c
> +++ b/libavformat/format.c
> @@ -33,6 +33,9 @@ static AVInputFormat *first_iformat = NULL;
>  /** head of registered output format linked list */
>  static AVOutputFormat *first_oformat = NULL;
>  
> +static AVInputFormat **last_iformat = &first_iformat;
> +static AVOutputFormat **last_oformat = &first_oformat;
> +
>  AVInputFormat *av_iformat_next(AVInputFormat *f)
>  {
>      if (f)
> @@ -51,20 +54,22 @@ AVOutputFormat *av_oformat_next(AVOutputFormat *f)
>  
>  void av_register_input_format(AVInputFormat *format)
>  {
> -    AVInputFormat **p = &first_iformat;
> +    AVInputFormat **p = last_iformat;
>  
>      format->next = NULL;
>      while(*p || avpriv_atomic_ptr_cas((void * volatile *)p, NULL, format))
>          p = &(*p)->next;
> +    last_iformat = &format->next;
>  }
>  
>  void av_register_output_format(AVOutputFormat *format)
>  {
> -    AVOutputFormat **p = &first_oformat;
> +    AVOutputFormat **p = last_oformat;
>  
>      format->next = NULL;
>      while(*p || avpriv_atomic_ptr_cas((void * volatile *)p, NULL, format))
>          p = &(*p)->next;
> +    last_oformat = &format->next;
>  }

LGTM.
-- 
FFmpeg = Fiendish and Fabulous Mastodontic Philosofic Ecumenical Gargoyle