mirror of https://github.com/FFmpeg/FFmpeg.git
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
451 lines
13 KiB
451 lines
13 KiB
/* |
|
* Copyright (c) 2002-2006 Michael Niedermayer <michaelni@gmx.at> |
|
* Copyright (c) 2006 Oded Shimon <ods15@ods15.dyndns.org> |
|
* |
|
* This file is part of FFmpeg. |
|
* |
|
* FFmpeg is free software; you can redistribute it and/or |
|
* modify it under the terms of the GNU Lesser General Public |
|
* License as published by the Free Software Foundation; either |
|
* version 2.1 of the License, or (at your option) any later version. |
|
* |
|
* FFmpeg is distributed in the hope that it will be useful, |
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of |
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
|
* Lesser General Public License for more details. |
|
* |
|
* You should have received a copy of the GNU Lesser General Public |
|
* License along with FFmpeg; if not, write to the Free Software |
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
|
*/ |
|
|
|
/** |
|
* @file |
|
* simple arithmetic expression evaluator. |
|
* |
|
* see http://joe.hotchkiss.com/programming/eval/eval.html |
|
*/ |
|
|
|
#include "libavutil/avutil.h" |
|
#include "eval.h" |
|
|
|
typedef struct Parser{ |
|
int stack_index; |
|
char *s; |
|
const double *const_value; |
|
const char * const *const_name; // NULL terminated |
|
double (* const *func1)(void *, double a); // NULL terminated |
|
const char * const *func1_name; // NULL terminated |
|
double (* const *func2)(void *, double a, double b); // NULL terminated |
|
const char * const *func2_name; // NULL terminated |
|
void *opaque; |
|
const char **error; |
|
#define VARS 10 |
|
double var[VARS]; |
|
} Parser; |
|
|
|
static const int8_t si_prefixes['z' - 'E' + 1]={ |
|
['y'-'E']= -24, |
|
['z'-'E']= -21, |
|
['a'-'E']= -18, |
|
['f'-'E']= -15, |
|
['p'-'E']= -12, |
|
['n'-'E']= - 9, |
|
['u'-'E']= - 6, |
|
['m'-'E']= - 3, |
|
['c'-'E']= - 2, |
|
['d'-'E']= - 1, |
|
['h'-'E']= 2, |
|
['k'-'E']= 3, |
|
['K'-'E']= 3, |
|
['M'-'E']= 6, |
|
['G'-'E']= 9, |
|
['T'-'E']= 12, |
|
['P'-'E']= 15, |
|
['E'-'E']= 18, |
|
['Z'-'E']= 21, |
|
['Y'-'E']= 24, |
|
}; |
|
|
|
double av_strtod(const char *numstr, char **tail) { |
|
double d; |
|
char *next; |
|
d = strtod(numstr, &next); |
|
/* if parsing succeeded, check for and interpret postfixes */ |
|
if (next!=numstr) { |
|
|
|
if(*next >= 'E' && *next <= 'z'){ |
|
int e= si_prefixes[*next - 'E']; |
|
if(e){ |
|
if(next[1] == 'i'){ |
|
d*= pow( 2, e/0.3); |
|
next+=2; |
|
}else{ |
|
d*= pow(10, e); |
|
next++; |
|
} |
|
} |
|
} |
|
|
|
if(*next=='B') { |
|
d*=8; |
|
next++; |
|
} |
|
} |
|
/* if requested, fill in tail with the position after the last parsed |
|
character */ |
|
if (tail) |
|
*tail = next; |
|
return d; |
|
} |
|
|
|
static int strmatch(const char *s, const char *prefix){ |
|
int i; |
|
for(i=0; prefix[i]; i++){ |
|
if(prefix[i] != s[i]) return 0; |
|
} |
|
return 1; |
|
} |
|
|
|
struct AVExpr { |
|
enum { |
|
e_value, e_const, e_func0, e_func1, e_func2, |
|
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 { |
|
int const_index; |
|
double (*func0)(double); |
|
double (*func1)(void *, double); |
|
double (*func2)(void *, double, double); |
|
} a; |
|
struct AVExpr *param[2]; |
|
}; |
|
|
|
static double eval_expr(Parser * p, AVExpr * e) { |
|
switch (e->type) { |
|
case e_value: return e->value; |
|
case e_const: return e->value * p->const_value[e->a.const_index]; |
|
case e_func0: return e->value * e->a.func0(eval_expr(p, e->param[0])); |
|
case e_func1: return e->value * e->a.func1(p->opaque, eval_expr(p, e->param[0])); |
|
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]); |
|
switch (e->type) { |
|
case e_mod: return e->value * (d - floor(d/d2)*d2); |
|
case e_max: return e->value * (d > d2 ? d : d2); |
|
case e_min: return e->value * (d < d2 ? d : d2); |
|
case e_eq: return e->value * (d == d2 ? 1.0 : 0.0); |
|
case e_gt: return e->value * (d > d2 ? 1.0 : 0.0); |
|
case e_gte: return e->value * (d >= d2 ? 1.0 : 0.0); |
|
case e_pow: return e->value * pow(d, d2); |
|
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); |
|
} |
|
} |
|
} |
|
return NAN; |
|
} |
|
|
|
static AVExpr * parse_expr(Parser *p); |
|
|
|
void ff_free_expr(AVExpr * e) { |
|
if (!e) return; |
|
ff_free_expr(e->param[0]); |
|
ff_free_expr(e->param[1]); |
|
av_freep(&e); |
|
} |
|
|
|
static AVExpr * parse_primary(Parser *p) { |
|
AVExpr * d = av_mallocz(sizeof(AVExpr)); |
|
char *next= p->s; |
|
int i; |
|
|
|
if (!d) |
|
return NULL; |
|
|
|
/* number */ |
|
d->value = av_strtod(p->s, &next); |
|
if(next != p->s){ |
|
d->type = e_value; |
|
p->s= next; |
|
return d; |
|
} |
|
d->value = 1; |
|
|
|
/* named constants */ |
|
for(i=0; p->const_name && p->const_name[i]; i++){ |
|
if(strmatch(p->s, p->const_name[i])){ |
|
p->s+= strlen(p->const_name[i]); |
|
d->type = e_const; |
|
d->a.const_index = i; |
|
return d; |
|
} |
|
} |
|
|
|
p->s= strchr(p->s, '('); |
|
if(p->s==NULL){ |
|
*p->error = "undefined constant or missing ("; |
|
p->s= next; |
|
ff_free_expr(d); |
|
return NULL; |
|
} |
|
p->s++; // "(" |
|
if (*next == '(') { // special case do-nothing |
|
av_freep(&d); |
|
d = parse_expr(p); |
|
if(p->s[0] != ')'){ |
|
*p->error = "missing )"; |
|
ff_free_expr(d); |
|
return NULL; |
|
} |
|
p->s++; // ")" |
|
return d; |
|
} |
|
d->param[0] = parse_expr(p); |
|
if(p->s[0]== ','){ |
|
p->s++; // "," |
|
d->param[1] = parse_expr(p); |
|
} |
|
if(p->s[0] != ')'){ |
|
*p->error = "missing )"; |
|
ff_free_expr(d); |
|
return NULL; |
|
} |
|
p->s++; // ")" |
|
|
|
d->type = e_func0; |
|
if( strmatch(next, "sinh" ) ) d->a.func0 = sinh; |
|
else if( strmatch(next, "cosh" ) ) d->a.func0 = cosh; |
|
else if( strmatch(next, "tanh" ) ) d->a.func0 = tanh; |
|
else if( strmatch(next, "sin" ) ) d->a.func0 = sin; |
|
else if( strmatch(next, "cos" ) ) d->a.func0 = cos; |
|
else if( strmatch(next, "tan" ) ) d->a.func0 = tan; |
|
else if( strmatch(next, "atan" ) ) d->a.func0 = atan; |
|
else if( strmatch(next, "asin" ) ) d->a.func0 = asin; |
|
else if( strmatch(next, "acos" ) ) d->a.func0 = acos; |
|
else if( strmatch(next, "exp" ) ) d->a.func0 = exp; |
|
else if( strmatch(next, "log" ) ) d->a.func0 = log; |
|
else if( strmatch(next, "abs" ) ) d->a.func0 = fabs; |
|
else if( strmatch(next, "squish") ) d->type = e_squish; |
|
else if( strmatch(next, "gauss" ) ) d->type = e_gauss; |
|
else if( strmatch(next, "mod" ) ) d->type = e_mod; |
|
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, "gte" ) ) d->type = e_gte; |
|
else if( strmatch(next, "gt" ) ) d->type = e_gt; |
|
else if( strmatch(next, "lte" ) ) { AVExpr * tmp = d->param[1]; d->param[1] = d->param[0]; d->param[0] = tmp; d->type = e_gt; } |
|
else if( strmatch(next, "lt" ) ) { AVExpr * 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])){ |
|
d->a.func1 = p->func1[i]; |
|
d->type = e_func1; |
|
return d; |
|
} |
|
} |
|
|
|
for(i=0; p->func2_name && p->func2_name[i]; i++){ |
|
if(strmatch(next, p->func2_name[i])){ |
|
d->a.func2 = p->func2[i]; |
|
d->type = e_func2; |
|
return d; |
|
} |
|
} |
|
|
|
*p->error = "unknown function"; |
|
ff_free_expr(d); |
|
return NULL; |
|
} |
|
|
|
return d; |
|
} |
|
|
|
static AVExpr * new_eval_expr(int type, int value, AVExpr *p0, AVExpr *p1){ |
|
AVExpr * e = av_mallocz(sizeof(AVExpr)); |
|
if (!e) |
|
return NULL; |
|
e->type =type ; |
|
e->value =value ; |
|
e->param[0] =p0 ; |
|
e->param[1] =p1 ; |
|
return e; |
|
} |
|
|
|
static AVExpr * parse_pow(Parser *p, int *sign){ |
|
*sign= (*p->s == '+') - (*p->s == '-'); |
|
p->s += *sign&1; |
|
return parse_primary(p); |
|
} |
|
|
|
static AVExpr * parse_factor(Parser *p){ |
|
int sign, sign2; |
|
AVExpr * e = parse_pow(p, &sign); |
|
while(p->s[0]=='^'){ |
|
p->s++; |
|
e= new_eval_expr(e_pow, 1, e, parse_pow(p, &sign2)); |
|
if (!e) |
|
return NULL; |
|
if (e->param[1]) e->param[1]->value *= (sign2|1); |
|
} |
|
if (e) e->value *= (sign|1); |
|
return e; |
|
} |
|
|
|
static AVExpr * parse_term(Parser *p){ |
|
AVExpr * e = parse_factor(p); |
|
while(p->s[0]=='*' || p->s[0]=='/'){ |
|
int c= *p->s++; |
|
e= new_eval_expr(c == '*' ? e_mul : e_div, 1, e, parse_factor(p)); |
|
if (!e) |
|
return NULL; |
|
} |
|
return e; |
|
} |
|
|
|
static AVExpr * parse_subexpr(Parser *p) { |
|
AVExpr * e = parse_term(p); |
|
while(*p->s == '+' || *p->s == '-') { |
|
e= new_eval_expr(e_add, 1, e, parse_term(p)); |
|
if (!e) |
|
return NULL; |
|
}; |
|
|
|
return e; |
|
} |
|
|
|
static AVExpr * parse_expr(Parser *p) { |
|
AVExpr * e; |
|
|
|
if(p->stack_index <= 0) //protect against stack overflows |
|
return NULL; |
|
p->stack_index--; |
|
|
|
e = parse_subexpr(p); |
|
|
|
while(*p->s == ';') { |
|
p->s++; |
|
e= new_eval_expr(e_last, 1, e, parse_subexpr(p)); |
|
if (!e) |
|
return NULL; |
|
}; |
|
|
|
p->stack_index++; |
|
|
|
return e; |
|
} |
|
|
|
static int verify_expr(AVExpr * e) { |
|
if (!e) return 0; |
|
switch (e->type) { |
|
case e_value: |
|
case e_const: return 1; |
|
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]); |
|
} |
|
} |
|
|
|
AVExpr *ff_parse_expr(const char *s, const char * const *const_name, |
|
double (* const *func1)(void *, double), const char * const *func1_name, |
|
double (* const *func2)(void *, double, double), const char * const *func2_name, |
|
const char **error){ |
|
Parser p; |
|
AVExpr *e = NULL; |
|
char *w = av_malloc(strlen(s) + 1); |
|
char *wp = w; |
|
|
|
if (!w) |
|
goto end; |
|
|
|
while (*s) |
|
if (!isspace(*s++)) *wp++ = s[-1]; |
|
*wp++ = 0; |
|
|
|
p.stack_index=100; |
|
p.s= w; |
|
p.const_name = const_name; |
|
p.func1 = func1; |
|
p.func1_name = func1_name; |
|
p.func2 = func2; |
|
p.func2_name = func2_name; |
|
p.error= error; |
|
|
|
e = parse_expr(&p); |
|
if (!verify_expr(e)) { |
|
ff_free_expr(e); |
|
e = NULL; |
|
} |
|
end: |
|
av_free(w); |
|
return e; |
|
} |
|
|
|
double ff_eval_expr(AVExpr * e, const double *const_value, void *opaque) { |
|
Parser p; |
|
|
|
p.const_value= const_value; |
|
p.opaque = opaque; |
|
return eval_expr(&p, e); |
|
} |
|
|
|
double ff_parse_and_eval_expr(const char *s, const double *const_value, const char * const *const_name, |
|
double (* const *func1)(void *, double), const char * const *func1_name, |
|
double (* const *func2)(void *, double, double), const char * const *func2_name, |
|
void *opaque, const char **error){ |
|
AVExpr * e = ff_parse_expr(s, const_name, func1, func1_name, func2, func2_name, error); |
|
double d; |
|
if (!e) return NAN; |
|
d = ff_eval_expr(e, const_value, opaque); |
|
ff_free_expr(e); |
|
return d; |
|
} |
|
|
|
#ifdef TEST |
|
#undef printf |
|
static double const_values[]={ |
|
M_PI, |
|
M_E, |
|
0 |
|
}; |
|
static const char *const_names[]={ |
|
"PI", |
|
"E", |
|
0 |
|
}; |
|
int main(void){ |
|
int i; |
|
printf("%f == 12.7\n", ff_parse_and_eval_expr("1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)", const_values, const_names, NULL, NULL, NULL, NULL, NULL, NULL)); |
|
printf("%f == 0.931322575\n", ff_parse_and_eval_expr("80G/80Gi", const_values, const_names, NULL, NULL, NULL, NULL, NULL, NULL)); |
|
|
|
for(i=0; i<1050; i++){ |
|
START_TIMER |
|
ff_parse_and_eval_expr("1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)", const_values, const_names, NULL, NULL, NULL, NULL, NULL, NULL); |
|
STOP_TIMER("ff_parse_and_eval_expr") |
|
} |
|
return 0; |
|
} |
|
#endif
|
|
|