Also add helper functions to allocate and free such a struct, and make it
usable by providing a new av_eval_expr2 function for which you can specify a
custom AVExprState.
Signed-off-by: Marton Balint <c...@passwd.hu>
---
doc/APIchanges | 4 ++++
libavutil/eval.c | 36 +++++++++++++++++++++++++-----------
libavutil/eval.h | 41 +++++++++++++++++++++++++++++++++++++++++
libavutil/version.h | 2 +-
4 files changed, 71 insertions(+), 12 deletions(-)
diff --git a/doc/APIchanges b/doc/APIchanges
index 3c24dc6fbc..d0b33bda02 100644
--- a/doc/APIchanges
+++ b/doc/APIchanges
@@ -15,6 +15,10 @@ libavutil: 2017-10-21
API changes, most recent first:
+2020-01-xx - xxxxxxxxxx - lavu 56.39.100 - eval.h
+ Add AVExprState struct and av_expr_eval2, av_expr_state_alloc,
+ av_expr_state_free functions
+
2019-12-27 - xxxxxxxxxx - lavu 56.38.100 - eval.h
Add av_expr_count_func().
diff --git a/libavutil/eval.c b/libavutil/eval.c
index d527f6a9d0..4619d0fba0 100644
--- a/libavutil/eval.c
+++ b/libavutil/eval.c
@@ -53,7 +53,6 @@ typedef struct Parser {
void *opaque;
int log_offset;
void *log_ctx;
-#define VARS 10
double *var;
} Parser;
@@ -173,7 +172,7 @@ struct AVExpr {
double (*func2)(void *, double, double);
} a;
struct AVExpr *param[3];
- double *var;
+ AVExprState *state;
};
static double etime(double v)
@@ -191,7 +190,7 @@ static double eval_expr(Parser *p, AVExpr *e)
case e_func2: return e->value * e->a.func2(p->opaque, eval_expr(p,
e->param[0]), eval_expr(p, e->param[1]));
case e_squish: return 1/(1+exp(4*eval_expr(p, e->param[0])));
case e_gauss: { double d = eval_expr(p, e->param[0]); return
exp(-d*d/2)/sqrt(2*M_PI); }
- case e_ld: return e->value * p->var[av_clip(eval_expr(p,
e->param[0]), 0, VARS-1)];
+ case e_ld: return e->value * p->var[av_clip(eval_expr(p,
e->param[0]), 0, AV_EXPR_STATE_NB_VARS-1)];
case e_isnan: return e->value * !!isnan(eval_expr(p, e->param[0]));
case e_isinf: return e->value * !!isinf(eval_expr(p, e->param[0]));
case e_floor: return e->value * floor(eval_expr(p, e->param[0]));
@@ -230,7 +229,7 @@ static double eval_expr(Parser *p, AVExpr *e)
return x;
}
case e_random:{
- int idx= av_clip(eval_expr(p, e->param[0]), 0, VARS-1);
+ int idx= av_clip(eval_expr(p, e->param[0]), 0,
AV_EXPR_STATE_NB_VARS-1);
uint64_t r= isnan(p->var[idx]) ? 0 : p->var[idx];
r= r*1664525+1013904223;
p->var[idx]= r;
@@ -245,7 +244,7 @@ static double eval_expr(Parser *p, AVExpr *e)
case e_taylor: {
double t = 1, d = 0, v;
double x = eval_expr(p, e->param[1]);
- int id = e->param[2] ? av_clip(eval_expr(p, e->param[2]), 0,
VARS-1) : 0;
+ int id = e->param[2] ? av_clip(eval_expr(p, e->param[2]), 0,
AV_EXPR_STATE_NB_VARS-1) : 0;
int i;
double var0 = p->var[id];
for(i=0; i<1000; i++) {
@@ -320,7 +319,7 @@ static double eval_expr(Parser *p, AVExpr *e)
case e_div: return e->value * ((!CONFIG_FTRAPV || d2 ) ? (d /
d2) : d * INFINITY);
case e_add: return e->value * (d + d2);
case e_last:return e->value * d2;
- case e_st : return e->value * (p->var[av_clip(d, 0, VARS-1)]=
d2);
+ case e_st : return e->value * (p->var[av_clip(d, 0,
AV_EXPR_STATE_NB_VARS-1)]= d2);
case e_hypot:return e->value * hypot(d, d2);
case e_atan2:return e->value * atan2(d, d2);
case e_bitand: return isnan(d) || isnan(d2) ? NAN : e->value *
((long int)d & (long int)d2);
@@ -333,13 +332,23 @@ static double eval_expr(Parser *p, AVExpr *e)
static int parse_expr(AVExpr **e, Parser *p);
+AVExprState *av_expr_state_alloc(void)
+{
+ return av_mallocz(sizeof(AVExprState));
+}
+
+void av_expr_state_free(AVExprState **ps)
+{
+ av_freep(ps);
+}
+
void av_expr_free(AVExpr *e)
{
if (!e) return;
av_expr_free(e->param[0]);
av_expr_free(e->param[1]);
av_expr_free(e->param[2]);
- av_freep(&e->var);
+ av_expr_state_free(&e->state);
av_freep(&e);
}
@@ -724,8 +733,8 @@ int av_expr_parse(AVExpr **expr, const char *s,
ret = AVERROR(EINVAL);
goto end;
}
- e->var= av_mallocz(sizeof(double) *VARS);
- if (!e->var) {
+ e->state = av_expr_state_alloc();
+ if (!e->state) {
ret = AVERROR(ENOMEM);
goto end;
}
@@ -763,16 +772,21 @@ int av_expr_count_func(AVExpr *e, unsigned *counter, int
size, int arg)
return expr_count(e, counter, size, ((int[]){e_const, e_func1,
e_func2})[arg]);
}
-double av_expr_eval(AVExpr *e, const double *const_values, void *opaque)
+double av_expr_eval2(AVExpr *e, AVExprState *s, const double *const_values,
void *opaque)
{
Parser p = { 0 };
- p.var= e->var;
+ p.var = s ? s->vars : e->state->vars;
p.const_values = const_values;
p.opaque = opaque;
return eval_expr(&p, e);
}
+double av_expr_eval(AVExpr *e, const double *const_values, void *opaque)
+{
+ return av_expr_eval2(e, NULL, const_values, opaque);
+}
+
int av_expr_parse_and_eval(double *d, const char *s,
const char * const *const_names, const double
*const_values,
const char * const *func1_names, double (* const
*funcs1)(void *, double),
diff --git a/libavutil/eval.h b/libavutil/eval.h
index 068c62cdab..d5b34e54e8 100644
--- a/libavutil/eval.h
+++ b/libavutil/eval.h
@@ -30,6 +30,21 @@
typedef struct AVExpr AVExpr;
+/**
+ * This structure stores a state used by the expression evaluator.
+ * It must be allocated and freed with its proper allocation functions.
+ *
+ * @see av_expr_state_alloc()
+ * @see av_expr_state_free()
+ */
+typedef struct AVExprState {
