[vlc-devel] [PATCH 2/8] playlist/engine: RateOffsetCallback: refactor

[Rémi Denis-Courmont]

Le sunnuntaina 21. toukokuuta 2017, 20.48.12 EEST Filip Roséen a écrit :
> Besides the shortening of the implementation, the refactor also make
> sure that we return an error-code if var_SetFloat fails - instead of
> silently pretending everything was ok.

var_Set() can only fail if the variable does not exist, which should be 
impossible (I think). So I am not quite sure what you are trying to achieve 
here.

> ---
>  src/playlist/engine.c | 45 ++++++++++++++++-----------------------------
>  1 file changed, 16 insertions(+), 29 deletions(-)
> 
> diff --git a/src/playlist/engine.c b/src/playlist/engine.c
> index eeacbc59e7..848a86ad45 100644
> --- a/src/playlist/engine.c
> +++ b/src/playlist/engine.c
> @@ -124,46 +124,33 @@ static int RateOffsetCallback( vlc_object_t *obj, char
> const *psz_cmd, playlist_t *p_playlist = (playlist_t *)obj;
>      VLC_UNUSED(oldval); VLC_UNUSED(p_data); VLC_UNUSED(newval);
> 
> -    static const float pf_rate[] = {
> +    static const float rates[] = {
>          1.0/64, 1.0/32, 1.0/16, 1.0/8, 1.0/4, 1.0/3, 1.0/2, 2.0/3,
>          1.0/1,
>          3.0/2, 2.0/1, 3.0/1, 4.0/1, 8.0/1, 16.0/1, 32.0/1, 64.0/1,
>      };
> -    const size_t i_rate_count = sizeof(pf_rate)/sizeof(*pf_rate);
> -
> -    float f_rate;
> -    struct input_thread_t *input;
> 
>      PL_LOCK;
> -    input = pl_priv( p_playlist )->p_input;
> -    f_rate = var_GetFloat( input ? (vlc_object_t *)input : obj, "rate" );
> +    input_thread_t *input = pl_priv( p_playlist )->p_input;
> +    float current_rate = var_GetFloat( input ? VLC_OBJECT( input ) : obj,
> "rate" ); PL_UNLOCK;
> 
> -    if( !strcmp( psz_cmd, "rate-faster" ) )
> -    {
> -        /* compensate for input rounding errors */
> -        float r = f_rate * 1.1f;
> -        for( size_t i = 0; i < i_rate_count; i++ )
> -            if( r < pf_rate[i] )
> -            {
> -                f_rate = pf_rate[i];
> -                break;
> -            }
> -    }
> -    else
> +    const bool faster = !strcmp( psz_cmd, "rate-faster" );
> +    float rate = current_rate * ( faster ? 1.1f : 0.9f );
> +
> +    /* find closest rate (if any) in the desired direction */
> +    for( size_t i = 0; i < ARRAY_SIZE( rates ); ++i )
>      {
> -        /* compensate for input rounding errors */
> -        float r = f_rate * .9f;
> -        for( size_t i = 1; i < i_rate_count; i++ )
> -            if( r <= pf_rate[i] )
> -            {
> -                f_rate = pf_rate[i - 1];
> -                break;
> -            }
> +        if( ( faster && rates[i] > rate ) ||
> +            (!faster && rates[i] >= rate && i ) )
> +        {
> +            rate = faster ? rates[i] : rates[i-1];
> +            break;
> +        }
>      }
> 
> -    var_SetFloat( p_playlist, "rate", f_rate );
> -    return VLC_SUCCESS;
> +
> +    return var_SetFloat( p_playlist, "rate", rate );
>  }
> 
>  static int VideoSplitterCallback( vlc_object_t *p_this, char const
> *psz_cmd,


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