[Pixman] [PATCH v10 09/15] pixman-filter: don't range-check in filter functions

[Oded Gabbay]

On Tue, Feb 2, 2016 at 8:28 AM,  <spitzak at gmail.com> wrote:
> From: Bill Spitzak <spitzak at gmail.com>
>
> The integral will not be called outside the width so there is no need
> to check against these.
>
> v9: merged commits for cubic and impulse into same one
>
> Signed-off-by: Bill Spitzak <spitzak at gmail.com>
> ---
>  pixman/pixman-filter.c | 18 ++++++++----------
>  1 file changed, 8 insertions(+), 10 deletions(-)
>
> diff --git a/pixman/pixman-filter.c b/pixman/pixman-filter.c
> index bd4e174..b6f8eb4 100644
> --- a/pixman/pixman-filter.c
> +++ b/pixman/pixman-filter.c
> @@ -45,7 +45,7 @@ typedef struct
>  static double
>  impulse_kernel (double x)
>  {
> -    return (x == 0.0)? 1.0 : 0.0;
> +    return 1;
>  }
>
>  static double
> @@ -109,18 +109,16 @@ general_cubic (double x, double B, double C)
>
>      if (ax < 1)
>      {
> -       return ((12 - 9 * B - 6 * C) * ax * ax * ax +
> -               (-18 + 12 * B + 6 * C) * ax * ax + (6 - 2 * B)) / 6;
> -    }
> -    else if (ax >= 1 && ax < 2)
> -    {
> -       return ((-B - 6 * C) * ax * ax * ax +
> -               (6 * B + 30 * C) * ax * ax + (-12 * B - 48 * C) *
> -               ax + (8 * B + 24 * C)) / 6;
> +       return (((12 - 9 * B - 6 * C) * ax +
> +                (-18 + 12 * B + 6 * C)) * ax * ax +
> +               (6 - 2 * B)) / 6;
>      }
>      else
>      {
> -       return 0;
> +       return ((((-B - 6 * C) * ax +
> +                (6 * B + 30 * C)) * ax +
> +               (-12 * B - 48 * C)) * ax +
> +               (8 * B + 24 * C)) / 6;
>      }
>  }
>
> --
> 1.9.1
>
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I'm sorry, but I still don't see the real benefit of removing those
checks, compared to the robustness of the code and I don't have the
sufficient knowledge to decide whether your commit message is true in
all cases or not.