/*
* simple arithmetic expression evaluator
*
- * Copyright (c) 2002 Michael Niedermayer <michaelni@gmx.at>
+ * Copyright (c) 2002-2006 Michael Niedermayer <michaelni@gmx.at>
+ * Copyright (c) 2006 Oded Shimon <ods15@ods15.dyndns.org>
*
* This file is part of FFmpeg.
*
char **func2_name; // NULL terminated
void *opaque;
char **error;
+#define VARS 10
+ double var[VARS];
} Parser;
static int8_t si_prefixes['z' - 'E' + 1]={
if(*next=='B') {
d*=8;
- *next++;
+ next++;
}
}
/* if requested, fill in tail with the position after the last parsed
struct ff_expr_s {
enum {
e_value, e_const, e_func0, e_func1, e_func2,
- e_squish, e_gauss,
+ e_squish, e_gauss, e_ld,
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,
} type;
double value; // is sign in other types
union {
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_while: {
+ double d = NAN;
+ while(eval_expr(p, e->param[0]))
+ d=eval_expr(p, e->param[1]);
+ return d;
+ }
default: {
double d = eval_expr(p, e->param[0]);
double d2 = eval_expr(p, e->param[1]);
case e_mul: return e->value * (d * d2);
case e_div: return e->value * (d / d2);
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);
}
}
}
else if( strmatch(next, "max" ) ) d->type = e_max;
else if( strmatch(next, "min" ) ) d->type = e_min;
else if( strmatch(next, "eq" ) ) d->type = e_eq;
- else if( strmatch(next, "gt" ) ) d->type = e_gt;
else if( strmatch(next, "gte" ) ) d->type = e_gte;
- else if( strmatch(next, "lt" ) ) { AVEvalExpr * tmp = d->param[1]; d->param[1] = d->param[0]; d->param[0] = tmp; d->type = e_gte; }
+ else if( strmatch(next, "gt" ) ) d->type = e_gt;
else if( strmatch(next, "lte" ) ) { AVEvalExpr * tmp = d->param[1]; d->param[1] = d->param[0]; d->param[0] = tmp; d->type = e_gt; }
+ else if( strmatch(next, "lt" ) ) { AVEvalExpr * tmp = d->param[1]; d->param[1] = d->param[0]; d->param[0] = tmp; d->type = e_gte; }
+ else if( strmatch(next, "ld" ) ) d->type = e_ld;
+ else if( strmatch(next, "st" ) ) d->type = e_st;
+ else if( strmatch(next, "while" ) ) d->type = e_while;
else {
for(i=0; p->func1_name && p->func1_name[i]; i++){
if(strmatch(next, p->func1_name[i])){
return e;
}
+static AVEvalExpr * parse_subexpr(Parser *p) {
+ AVEvalExpr * e = parse_term(p);
+ while(*p->s == '+' || *p->s == '-') {
+ e= new_eval_expr(e_add, 1, e, parse_term(p));
+ };
+
+ return e;
+}
+
static AVEvalExpr * parse_expr(Parser *p) {
AVEvalExpr * e;
return NULL;
p->stack_index--;
- e = parse_term(p);
+ e = parse_subexpr(p);
- while(*p->s == '+' || *p->s == '-') {
- e= new_eval_expr(e_add, 1, e, parse_term(p));
+ while(*p->s == ';') {
+ p->s++;
+ e= new_eval_expr(e_last, 1, e, parse_subexpr(p));
};
p->stack_index++;
case e_func0:
case e_func1:
case e_squish:
+ case e_ld:
case e_gauss: return verify_expr(e->param[0]);
default: return verify_expr(e->param[0]) && verify_expr(e->param[1]);
}
char **error){
Parser p;
AVEvalExpr * e;
+ char w[strlen(s) + 1], * wp = w;
+
+ while (*s)
+ if (!isspace(*s++)) *wp++ = s[-1];
+ *wp++ = 0;
p.stack_index=100;
- p.s= s;
+ p.s= w;
p.const_name = const_name;
p.func1 = func1;
p.func1_name = func1_name;