[FFmpeg-devel] [PATCH] eval: add sqrt function for computing the squared root

[Víctor Paesa]

Hi,

On Tue, May 3, 2011 at 23:32, Stefano Sabatini wrote:
> ---
>  doc/eval.texi    |    3 +++
>  libavutil/eval.c |    4 ++++
>  2 files changed, 7 insertions(+), 0 deletions(-)
>
> diff --git a/doc/eval.texi b/doc/eval.texi
> index d0e04c0..fe3eea6 100644
> --- a/doc/eval.texi
> +++ b/doc/eval.texi
> @@ -72,6 +72,9 @@ integer. For example, "floor(-1.5)" is "-2.0".
>  @item trunc(expr)
>  Round the value of expression @var{expr} towards zero to the nearest
>  integer. For example, "trunc(-1.5)" is "-1.0".
> +
> + at item sqrt(expr)
> +Compute the squared root of @var{expr}.

I think is "square root".

>  @end table
>
>  Note that:
> diff --git a/libavutil/eval.c b/libavutil/eval.c
> index 494b936..164100d 100644
> --- a/libavutil/eval.c
> +++ b/libavutil/eval.c
> @@ -122,6 +122,7 @@ struct AVExpr {
>         e_mod, e_max, e_min, e_eq, e_gt, e_gte,
>         e_pow, e_mul, e_div, e_add,
>         e_last, e_st, e_while, e_floor, e_ceil, e_trunc,
> +        e_sqrt,
>     } type;
>     double value; // is sign in other types
>     union {
> @@ -148,6 +149,7 @@ static double eval_expr(Parser *p, AVExpr *e)
>         case e_floor:  return e->value * floor(eval_expr(p, e->param[0]));
>         case e_ceil :  return e->value * ceil (eval_expr(p, e->param[0]));
>         case e_trunc:  return e->value * trunc(eval_expr(p, e->param[0]));
> +        case e_sqrt:   return e->value * sqrt (eval_expr(p, e->param[0]));
>         case e_while: {
>             double d = NAN;
>             while (eval_expr(p, e->param[0]))
> @@ -282,6 +284,7 @@ static int parse_primary(AVExpr **e, Parser *p)
>     else if (strmatch(next, "floor" )) d->type = e_floor;
>     else if (strmatch(next, "ceil"  )) d->type = e_ceil;
>     else if (strmatch(next, "trunc" )) d->type = e_trunc;
> +    else if (strmatch(next, "sqrt"  )) d->type = e_sqrt;
>     else {
>         for (i=0; p->func1_names && p->func1_names[i]; i++) {
>             if (strmatch(next, p->func1_names[i])) {
> @@ -449,6 +452,7 @@ static int verify_expr(AVExpr *e)
>         case e_floor:
>         case e_ceil:
>         case e_trunc:
> +        case e_sqrt:
>             return verify_expr(e->param[0]);
>         default: return verify_expr(e->param[0]) && verify_expr(e->param[1]);
>     }

Regards,
Víctor