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eval: add sqrt function for computing the square root

This commit is contained in:
Stefano Sabatini 2011-05-03 23:31:14 +02:00
parent 5d2ce3a778
commit e5272e729e
3 changed files with 11 additions and 1 deletions
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4
doc/eval.texi
View File

@ -72,6 +72,10 @@ 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".
@item sqrt(expr)
Compute the square root of @var{expr}. This is equivalent to
"(@var{expr})^.5".
@end table
Note that:

2
libavutil/avutil.h
View File

@ -41,7 +41,7 @@
#define LIBAVUTIL_VERSION_MAJOR 51
#define LIBAVUTIL_VERSION_MINOR 2
#define LIBAVUTIL_VERSION_MICRO 0
#define LIBAVUTIL_VERSION_MICRO 1
#define LIBAVUTIL_VERSION_INT AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \
LIBAVUTIL_VERSION_MINOR, \

6
libavutil/eval.c
View File

@ -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]);
}
@ -628,6 +632,8 @@ int main(void)
"trunc(-123.123)",
"ceil(123.123)",
"ceil(-123.123)",
"sqrt(1764)",
"sqrt(-1)",
NULL
};