2 * Copyright (c) 2002-2006 Michael Niedermayer <michaelni@gmx.at>
3 * Copyright (c) 2006 Oded Shimon <ods15@ods15.dyndns.org>
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 * simple arithmetic expression evaluator.
26 * see http://joe.hotchkiss.com/programming/eval/eval.html
29 #include "libavutil/avutil.h"
32 typedef struct Parser {
36 const double *const_values;
37 const char * const *const_names; // NULL terminated
38 double (* const *funcs1)(void *, double a); // NULL terminated
39 const char * const *func1_names; // NULL terminated
40 double (* const *funcs2)(void *, double a, double b); // NULL terminated
41 const char * const *func2_names; // NULL terminated
49 static const AVClass class = { "Eval", av_default_item_name, NULL, LIBAVUTIL_VERSION_INT, offsetof(Parser,log_offset), offsetof(Parser,log_ctx) };
51 static const int8_t si_prefixes['z' - 'E' + 1] = {
74 double av_strtod(const char *numstr, char **tail)
78 d = strtod(numstr, &next);
79 /* if parsing succeeded, check for and interpret postfixes */
81 if (*next >= 'E' && *next <= 'z') {
82 int e= si_prefixes[*next - 'E'];
99 /* if requested, fill in tail with the position after the last parsed
106 static int strmatch(const char *s, const char *prefix)
109 for (i=0; prefix[i]; i++) {
110 if (prefix[i] != s[i]) return 0;
117 e_value, e_const, e_func0, e_func1, e_func2,
118 e_squish, e_gauss, e_ld,
119 e_mod, e_max, e_min, e_eq, e_gt, e_gte,
120 e_pow, e_mul, e_div, e_add,
121 e_last, e_st, e_while,
123 double value; // is sign in other types
126 double (*func0)(double);
127 double (*func1)(void *, double);
128 double (*func2)(void *, double, double);
130 struct AVExpr *param[2];
133 static double eval_expr(Parser *p, AVExpr *e)
136 case e_value: return e->value;
137 case e_const: return e->value * p->const_values[e->a.const_index];
138 case e_func0: return e->value * e->a.func0(eval_expr(p, e->param[0]));
139 case e_func1: return e->value * e->a.func1(p->opaque, eval_expr(p, e->param[0]));
140 case e_func2: return e->value * e->a.func2(p->opaque, eval_expr(p, e->param[0]), eval_expr(p, e->param[1]));
141 case e_squish: return 1/(1+exp(4*eval_expr(p, e->param[0])));
142 case e_gauss: { double d = eval_expr(p, e->param[0]); return exp(-d*d/2)/sqrt(2*M_PI); }
143 case e_ld: return e->value * p->var[av_clip(eval_expr(p, e->param[0]), 0, VARS-1)];
146 while (eval_expr(p, e->param[0]))
147 d=eval_expr(p, e->param[1]);
151 double d = eval_expr(p, e->param[0]);
152 double d2 = eval_expr(p, e->param[1]);
154 case e_mod: return e->value * (d - floor(d/d2)*d2);
155 case e_max: return e->value * (d > d2 ? d : d2);
156 case e_min: return e->value * (d < d2 ? d : d2);
157 case e_eq: return e->value * (d == d2 ? 1.0 : 0.0);
158 case e_gt: return e->value * (d > d2 ? 1.0 : 0.0);
159 case e_gte: return e->value * (d >= d2 ? 1.0 : 0.0);
160 case e_pow: return e->value * pow(d, d2);
161 case e_mul: return e->value * (d * d2);
162 case e_div: return e->value * (d / d2);
163 case e_add: return e->value * (d + d2);
164 case e_last:return e->value * d2;
165 case e_st : return e->value * (p->var[av_clip(d, 0, VARS-1)]= d2);
172 static int parse_expr(AVExpr **e, Parser *p);
174 void av_free_expr(AVExpr *e)
177 av_free_expr(e->param[0]);
178 av_free_expr(e->param[1]);
182 static int parse_primary(AVExpr **e, Parser *p)
184 AVExpr *d = av_mallocz(sizeof(AVExpr));
185 char *next = p->s, *s0 = p->s;
189 return AVERROR(ENOMEM);
192 d->value = av_strtod(p->s, &next);
201 /* named constants */
202 for (i=0; p->const_names && p->const_names[i]; i++) {
203 if (strmatch(p->s, p->const_names[i])) {
204 p->s+= strlen(p->const_names[i]);
206 d->a.const_index = i;
212 p->s= strchr(p->s, '(');
214 av_log(p, AV_LOG_ERROR, "Undefined constant or missing '(' in '%s'\n", s0);
217 return AVERROR(EINVAL);
220 if (*next == '(') { // special case do-nothing
222 if ((ret = parse_expr(&d, p)) < 0)
224 if (p->s[0] != ')') {
225 av_log(p, AV_LOG_ERROR, "Missing ')' in '%s'\n", s0);
227 return AVERROR(EINVAL);
233 if ((ret = parse_expr(&(d->param[0]), p)) < 0) {
239 parse_expr(&d->param[1], p);
241 if (p->s[0] != ')') {
242 av_log(p, AV_LOG_ERROR, "Missing ')' or too many args in '%s'\n", s0);
244 return AVERROR(EINVAL);
249 if (strmatch(next, "sinh" )) d->a.func0 = sinh;
250 else if (strmatch(next, "cosh" )) d->a.func0 = cosh;
251 else if (strmatch(next, "tanh" )) d->a.func0 = tanh;
252 else if (strmatch(next, "sin" )) d->a.func0 = sin;
253 else if (strmatch(next, "cos" )) d->a.func0 = cos;
254 else if (strmatch(next, "tan" )) d->a.func0 = tan;
255 else if (strmatch(next, "atan" )) d->a.func0 = atan;
256 else if (strmatch(next, "asin" )) d->a.func0 = asin;
257 else if (strmatch(next, "acos" )) d->a.func0 = acos;
258 else if (strmatch(next, "exp" )) d->a.func0 = exp;
259 else if (strmatch(next, "log" )) d->a.func0 = log;
260 else if (strmatch(next, "abs" )) d->a.func0 = fabs;
261 else if (strmatch(next, "squish")) d->type = e_squish;
262 else if (strmatch(next, "gauss" )) d->type = e_gauss;
263 else if (strmatch(next, "mod" )) d->type = e_mod;
264 else if (strmatch(next, "max" )) d->type = e_max;
265 else if (strmatch(next, "min" )) d->type = e_min;
266 else if (strmatch(next, "eq" )) d->type = e_eq;
267 else if (strmatch(next, "gte" )) d->type = e_gte;
268 else if (strmatch(next, "gt" )) d->type = e_gt;
269 else if (strmatch(next, "lte" )) { AVExpr *tmp = d->param[1]; d->param[1] = d->param[0]; d->param[0] = tmp; d->type = e_gt; }
270 else if (strmatch(next, "lt" )) { AVExpr *tmp = d->param[1]; d->param[1] = d->param[0]; d->param[0] = tmp; d->type = e_gte; }
271 else if (strmatch(next, "ld" )) d->type = e_ld;
272 else if (strmatch(next, "st" )) d->type = e_st;
273 else if (strmatch(next, "while" )) d->type = e_while;
275 for (i=0; p->func1_names && p->func1_names[i]; i++) {
276 if (strmatch(next, p->func1_names[i])) {
277 d->a.func1 = p->funcs1[i];
284 for (i=0; p->func2_names && p->func2_names[i]; i++) {
285 if (strmatch(next, p->func2_names[i])) {
286 d->a.func2 = p->funcs2[i];
293 av_log(p, AV_LOG_ERROR, "Unknown function in '%s'\n", s0);
295 return AVERROR(EINVAL);
302 static AVExpr *new_eval_expr(int type, int value, AVExpr *p0, AVExpr *p1)
304 AVExpr *e = av_mallocz(sizeof(AVExpr));
314 static int parse_pow(AVExpr **e, Parser *p, int *sign)
316 *sign= (*p->s == '+') - (*p->s == '-');
318 return parse_primary(e, p);
321 static int parse_factor(AVExpr **e, Parser *p)
323 int sign, sign2, ret;
324 AVExpr *e0, *e1, *e2;
325 if ((ret = parse_pow(&e0, p, &sign)) < 0)
330 if ((ret = parse_pow(&e2, p, &sign2)) < 0) {
334 e0 = new_eval_expr(e_pow, 1, e1, e2);
338 return AVERROR(ENOMEM);
340 if (e0->param[1]) e0->param[1]->value *= (sign2|1);
342 if (e0) e0->value *= (sign|1);
348 static int parse_term(AVExpr **e, Parser *p)
351 AVExpr *e0, *e1, *e2;
352 if ((ret = parse_factor(&e0, p)) < 0)
354 while (p->s[0]=='*' || p->s[0]=='/') {
357 if ((ret = parse_factor(&e2, p)) < 0) {
361 e0 = new_eval_expr(c == '*' ? e_mul : e_div, 1, e1, e2);
365 return AVERROR(ENOMEM);
372 static int parse_subexpr(AVExpr **e, Parser *p)
375 AVExpr *e0, *e1, *e2;
376 if ((ret = parse_term(&e0, p)) < 0)
378 while (*p->s == '+' || *p->s == '-') {
380 if ((ret = parse_term(&e2, p)) < 0) {
384 e0 = new_eval_expr(e_add, 1, e1, e2);
388 return AVERROR(ENOMEM);
396 static int parse_expr(AVExpr **e, Parser *p)
399 AVExpr *e0, *e1, *e2;
400 if (p->stack_index <= 0) //protect against stack overflows
401 return AVERROR(EINVAL);
404 if ((ret = parse_subexpr(&e0, p)) < 0)
406 while (*p->s == ';') {
408 if ((ret = parse_subexpr(&e2, p)) < 0) {
413 e0 = new_eval_expr(e_last, 1, e1, e2);
417 return AVERROR(ENOMEM);
426 static int verify_expr(AVExpr *e)
431 case e_const: return 1;
436 case e_gauss: return verify_expr(e->param[0]);
437 default: return verify_expr(e->param[0]) && verify_expr(e->param[1]);
441 int av_parse_expr(AVExpr **expr, const char *s,
442 const char * const *const_names,
443 const char * const *func1_names, double (* const *funcs1)(void *, double),
444 const char * const *func2_names, double (* const *funcs2)(void *, double, double),
445 int log_offset, void *log_ctx)
449 char *w = av_malloc(strlen(s) + 1);
455 return AVERROR(ENOMEM);
458 if (!isspace(*s++)) *wp++ = s[-1];
464 p.const_names = const_names;
466 p.func1_names = func1_names;
468 p.func2_names = func2_names;
469 p.log_offset = log_offset;
472 if ((ret = parse_expr(&e, &p)) < 0)
475 av_log(&p, AV_LOG_ERROR, "Invalid chars '%s' at the end of expression '%s'\n", p.s, s0);
476 ret = AVERROR(EINVAL);
479 if (!verify_expr(e)) {
481 ret = AVERROR(EINVAL);
490 double av_eval_expr(AVExpr *e, const double *const_values, void *opaque)
494 p.const_values = const_values;
496 return eval_expr(&p, e);
499 int av_parse_and_eval_expr(double *d, const char *s,
500 const char * const *const_names, const double *const_values,
501 const char * const *func1_names, double (* const *funcs1)(void *, double),
502 const char * const *func2_names, double (* const *funcs2)(void *, double, double),
503 void *opaque, int log_offset, void *log_ctx)
506 int ret = av_parse_expr(&e, s, const_names, func1_names, funcs1, func2_names, funcs2, log_offset, log_ctx);
512 *d = av_eval_expr(e, const_values, opaque);
514 return isnan(*d) ? AVERROR(EINVAL) : 0;
519 static double const_values[] = {
525 static const char *const_names[] = {
535 const char **expr, *exprs[] = {
537 "1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)",
558 "bar + PI + E + 100f*2 + foo",
559 "13k + 12f - foo(1, 2)",
565 for (expr = exprs; *expr; expr++) {
566 printf("Evaluating '%s'\n", *expr);
567 av_parse_and_eval_expr(&d, *expr,
568 const_names, const_values,
569 NULL, NULL, NULL, NULL, NULL, 0, NULL);
570 printf("'%s' -> %f\n\n", *expr, d);
573 av_parse_and_eval_expr(&d, "1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)",
574 const_names, const_values,
575 NULL, NULL, NULL, NULL, NULL, 0, NULL);
576 printf("%f == 12.7\n", d);
577 av_parse_and_eval_expr(&d, "80G/80Gi",
578 const_names, const_values,
579 NULL, NULL, NULL, NULL, NULL, 0, NULL);
580 printf("%f == 0.931322575\n", d);
582 for (i=0; i<1050; i++) {
584 av_parse_and_eval_expr(&d, "1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)",
585 const_names, const_values,
586 NULL, NULL, NULL, NULL, NULL, 0, NULL);
587 STOP_TIMER("av_parse_and_eval_expr")