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avfilter/avfiltergraph: fix constant string comparision
[ffmpeg.git] / libavutil / eval.c
1 /*
2 * Copyright (c) 2002-2006 Michael Niedermayer <michaelni@gmx.at>
3 * Copyright (c) 2006 Oded Shimon <ods15@ods15.dyndns.org>
4 *
5 * This file is part of FFmpeg.
6 *
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.
11 *
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.
16 *
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
20 */
21
22 /**
23 * @file
24 * simple arithmetic expression evaluator.
25 *
26 * see http://joe.hotchkiss.com/programming/eval/eval.html
27 */
28
29 #include <float.h>
30 #include "attributes.h"
31 #include "avutil.h"
32 #include "common.h"
33 #include "eval.h"
34 #include "ffmath.h"
35 #include "log.h"
36 #include "mathematics.h"
37 #include "mem.h"
38 #include "sfc64.h"
39 #include "time.h"
40 #include "avstring.h"
41 #include "reverse.h"
42
43 typedef struct Parser {
44 const AVClass *class;
45 int stack_index;
46 char *s;
47 const double *const_values;
48 const char * const *const_names; // NULL terminated
49 double (* const *funcs1)(void *, double a); // NULL terminated
50 const char * const *func1_names; // NULL terminated
51 double (* const *funcs2)(void *, double a, double b); // NULL terminated
52 const char * const *func2_names; // NULL terminated
53 void *opaque;
54 int log_offset;
55 void *log_ctx;
56 #define VARS 10
57 double *var;
58 FFSFC64 *prng_state;
59 } Parser;
60
61 static const AVClass eval_class = {
62 .class_name = "Eval",
63 .item_name = av_default_item_name,
64 .option = NULL,
65 .version = LIBAVUTIL_VERSION_INT,
66 .log_level_offset_offset = offsetof(Parser, log_offset),
67 .parent_log_context_offset = offsetof(Parser, log_ctx),
68 };
69
70 static const struct {
71 double bin_val;
72 double dec_val;
73 int8_t exp;
74 } si_prefixes['z' - 'E' + 1] = {
75 ['y'-'E']= { 8.271806125530276749e-25, 1e-24, -24 },
76 ['z'-'E']= { 8.4703294725430034e-22, 1e-21, -21 },
77 ['a'-'E']= { 8.6736173798840355e-19, 1e-18, -18 },
78 ['f'-'E']= { 8.8817841970012523e-16, 1e-15, -15 },
79 ['p'-'E']= { 9.0949470177292824e-13, 1e-12, -12 },
80 ['n'-'E']= { 9.3132257461547852e-10, 1e-9, -9 },
81 ['u'-'E']= { 9.5367431640625e-7, 1e-6, -6 },
82 ['m'-'E']= { 9.765625e-4, 1e-3, -3 },
83 ['c'-'E']= { 9.8431332023036951e-3, 1e-2, -2 },
84 ['d'-'E']= { 9.921256574801246e-2, 1e-1, -1 },
85 ['h'-'E']= { 1.0159366732596479e2, 1e2, 2 },
86 ['k'-'E']= { 1.024e3, 1e3, 3 },
87 ['K'-'E']= { 1.024e3, 1e3, 3 },
88 ['M'-'E']= { 1.048576e6, 1e6, 6 },
89 ['G'-'E']= { 1.073741824e9, 1e9, 9 },
90 ['T'-'E']= { 1.099511627776e12, 1e12, 12 },
91 ['P'-'E']= { 1.125899906842624e15, 1e15, 15 },
92 ['E'-'E']= { 1.152921504606847e18, 1e18, 18 },
93 ['Z'-'E']= { 1.1805916207174113e21, 1e21, 21 },
94 ['Y'-'E']= { 1.2089258196146292e24, 1e24, 24 },
95 };
96
97 static const struct {
98 const char *name;
99 double value;
100 } constants[] = {
101 { "E", M_E },
102 { "PI", M_PI },
103 { "PHI", M_PHI },
104 { "QP2LAMBDA", FF_QP2LAMBDA },
105 };
106
107 double av_strtod(const char *numstr, char **tail)
108 {
109 double d;
110 char *next;
111 if(numstr[0]=='0' && (numstr[1]|0x20)=='x') {
112 d = strtoul(numstr, &next, 16);
113 } else
114 d = strtod(numstr, &next);
115 /* if parsing succeeded, check for and interpret postfixes */
116 if (next!=numstr) {
117 if (next[0] == 'd' && next[1] == 'B') {
118 /* treat dB as decibels instead of decibytes */
119 d = ff_exp10(d / 20);
120 next += 2;
121 } else if (*next >= 'E' && *next <= 'z') {
122 int e= si_prefixes[*next - 'E'].exp;
123 if (e) {
124 if (next[1] == 'i') {
125 d*= si_prefixes[*next - 'E'].bin_val;
126 next+=2;
127 } else {
128 d*= si_prefixes[*next - 'E'].dec_val;
129 next++;
130 }
131 }
132 }
133
134 if (*next=='B') {
135 d*=8;
136 next++;
137 }
138 }
139 /* if requested, fill in tail with the position after the last parsed
140 character */
141 if (tail)
142 *tail = next;
143 return d;
144 }
145
146 #define IS_IDENTIFIER_CHAR(c) ((c) - '0' <= 9U || (c) - 'a' <= 25U || (c) - 'A' <= 25U || (c) == '_')
147
148 static int strmatch(const char *s, const char *prefix)
149 {
150 int i;
151 for (i=0; prefix[i]; i++) {
152 if (prefix[i] != s[i]) return 0;
153 }
154 /* return 1 only if the s identifier is terminated */
155 return !IS_IDENTIFIER_CHAR(s[i]);
156 }
157
158 struct AVExpr {
159 enum {
160 e_value, e_const, e_func0, e_func1, e_func2,
161 e_squish, e_gauss, e_ld, e_isnan, e_isinf,
162 e_mod, e_max, e_min, e_eq, e_gt, e_gte, e_lte, e_lt,
163 e_pow, e_mul, e_div, e_add,
164 e_last, e_st, e_while, e_taylor, e_root, e_floor, e_ceil, e_trunc, e_round,
165 e_sqrt, e_not, e_random, e_hypot, e_gcd,
166 e_if, e_ifnot, e_print, e_bitand, e_bitor, e_between, e_clip, e_atan2, e_lerp,
167 e_sgn, e_randomi
168 } type;
169 double value; // is sign in other types
170 int const_index;
171 union {
172 double (*func0)(double);
173 double (*func1)(void *, double);
174 double (*func2)(void *, double, double);
175 } a;
176 struct AVExpr *param[3];
177 double *var;
178 FFSFC64 *prng_state;
179 };
180
181 static double etime(double v)
182 {
183 return av_gettime() * 0.000001;
184 }
185
186 static double eval_expr(Parser *p, AVExpr *e)
187 {
188 switch (e->type) {
189 case e_value: return e->value;
190 case e_const: return e->value * p->const_values[e->const_index];
191 case e_func0: return e->value * e->a.func0(eval_expr(p, e->param[0]));
192 case e_func1: return e->value * e->a.func1(p->opaque, eval_expr(p, e->param[0]));
193 case e_func2: return e->value * e->a.func2(p->opaque, eval_expr(p, e->param[0]), eval_expr(p, e->param[1]));
194 case e_squish: return 1/(1+exp(4*eval_expr(p, e->param[0])));
195 case e_gauss: { double d = eval_expr(p, e->param[0]); return exp(-d*d/2)/sqrt(2*M_PI); }
196 case e_ld: return e->value * p->var[av_clip(eval_expr(p, e->param[0]), 0, VARS-1)];
197 case e_isnan: return e->value * !!isnan(eval_expr(p, e->param[0]));
198 case e_isinf: return e->value * !!isinf(eval_expr(p, e->param[0]));
199 case e_floor: return e->value * floor(eval_expr(p, e->param[0]));
200 case e_ceil : return e->value * ceil (eval_expr(p, e->param[0]));
201 case e_trunc: return e->value * trunc(eval_expr(p, e->param[0]));
202 case e_round: return e->value * round(eval_expr(p, e->param[0]));
203 case e_sgn: return e->value * FFDIFFSIGN(eval_expr(p, e->param[0]), 0);
204 case e_sqrt: return e->value * sqrt (eval_expr(p, e->param[0]));
205 case e_not: return e->value * (eval_expr(p, e->param[0]) == 0);
206 case e_if: return e->value * (eval_expr(p, e->param[0]) ? eval_expr(p, e->param[1]) :
207 e->param[2] ? eval_expr(p, e->param[2]) : 0);
208 case e_ifnot: return e->value * (!eval_expr(p, e->param[0]) ? eval_expr(p, e->param[1]) :
209 e->param[2] ? eval_expr(p, e->param[2]) : 0);
210 case e_clip: {
211 double x = eval_expr(p, e->param[0]);
212 double min = eval_expr(p, e->param[1]), max = eval_expr(p, e->param[2]);
213 if (isnan(min) || isnan(max) || isnan(x) || min > max)
214 return NAN;
215 return e->value * av_clipd(eval_expr(p, e->param[0]), min, max);
216 }
217 case e_between: {
218 double d = eval_expr(p, e->param[0]);
219 return e->value * (d >= eval_expr(p, e->param[1]) &&
220 d <= eval_expr(p, e->param[2]));
221 }
222 case e_lerp: {
223 double v0 = eval_expr(p, e->param[0]);
224 double v1 = eval_expr(p, e->param[1]);
225 double f = eval_expr(p, e->param[2]);
226 return v0 + (v1 - v0) * f;
227 }
228 case e_print: {
229 double x = eval_expr(p, e->param[0]);
230 int level = e->param[1] ? av_clip(eval_expr(p, e->param[1]), INT_MIN, INT_MAX) : AV_LOG_INFO;
231 av_log(p, level, "%f\n", x);
232 return x;
233 }
234
235 #define COMPUTE_NEXT_RANDOM() \
236 int idx = av_clip(eval_expr(p, e->param[0]), 0, VARS-1); \
237 FFSFC64 *s = p->prng_state + idx; \
238 uint64_t r; \
239 \
240 if (!s->counter) { \
241 r = isnan(p->var[idx]) ? 0 : p->var[idx]; \
242 ff_sfc64_init(s, r, r, r, 12); \
243 } \
244 r = ff_sfc64_get(s); \
245 p->var[idx] = r; \
246
247 case e_random: {
248 COMPUTE_NEXT_RANDOM();
249 return r * (1.0/UINT64_MAX);
250 }
251 case e_randomi: {
252 double min = eval_expr(p, e->param[1]);
253 double max = eval_expr(p, e->param[2]);
254 COMPUTE_NEXT_RANDOM();
255 return min + (max - min) * r / UINT64_MAX;
256 }
257 case e_while: {
258 double d = NAN;
259 while (eval_expr(p, e->param[0]))
260 d=eval_expr(p, e->param[1]);
261 return d;
262 }
263 case e_taylor: {
264 double t = 1, d = 0, v;
265 double x = eval_expr(p, e->param[1]);
266 int id = e->param[2] ? av_clip(eval_expr(p, e->param[2]), 0, VARS-1) : 0;
267 int i;
268 double var0 = p->var[id];
269 for(i=0; i<1000; i++) {
270 double ld = d;
271 p->var[id] = i;
272 v = eval_expr(p, e->param[0]);
273 d += t*v;
274 if(ld==d && v)
275 break;
276 t *= x / (i+1);
277 }
278 p->var[id] = var0;
279 return d;
280 }
281 case e_root: {
282 int i, j;
283 double low = -1, high = -1, v, low_v = -DBL_MAX, high_v = DBL_MAX;
284 double var0 = p->var[0];
285 double x_max = eval_expr(p, e->param[1]);
286 for(i=-1; i<1024; i++) {
287 if(i<255) {
288 p->var[0] = ff_reverse[i&255]*x_max/255;
289 } else {
290 p->var[0] = x_max*pow(0.9, i-255);
291 if (i&1) p->var[0] *= -1;
292 if (i&2) p->var[0] += low;
293 else p->var[0] += high;
294 }
295 v = eval_expr(p, e->param[0]);
296 if (v<=0 && v>low_v) {
297 low = p->var[0];
298 low_v = v;
299 }
300 if (v>=0 && v<high_v) {
301 high = p->var[0];
302 high_v = v;
303 }
304 if (low>=0 && high>=0){
305 for (j=0; j<1000; j++) {
306 p->var[0] = (low+high)*0.5;
307 if (low == p->var[0] || high == p->var[0])
308 break;
309 v = eval_expr(p, e->param[0]);
310 if (v<=0) low = p->var[0];
311 if (v>=0) high= p->var[0];
312 if (isnan(v)) {
313 low = high = v;
314 break;
315 }
316 }
317 break;
318 }
319 }
320 p->var[0] = var0;
321 return -low_v<high_v ? low : high;
322 }
323 default: {
324 double d = eval_expr(p, e->param[0]);
325 double d2 = eval_expr(p, e->param[1]);
326 switch (e->type) {
327 case e_mod: return e->value * (d - floor(d2 ? d / d2 : d * INFINITY) * d2);
328 case e_gcd: return e->value * av_gcd(d,d2);
329 case e_max: return e->value * (d > d2 ? d : d2);
330 case e_min: return e->value * (d < d2 ? d : d2);
331 case e_eq: return e->value * (d == d2 ? 1.0 : 0.0);
332 case e_gt: return e->value * (d > d2 ? 1.0 : 0.0);
333 case e_gte: return e->value * (d >= d2 ? 1.0 : 0.0);
334 case e_lt: return e->value * (d < d2 ? 1.0 : 0.0);
335 case e_lte: return e->value * (d <= d2 ? 1.0 : 0.0);
336 case e_pow: return e->value * pow(d, d2);
337 case e_mul: return e->value * (d * d2);
338 case e_div: return e->value * (d2 ? (d / d2) : d * INFINITY);
339 case e_add: return e->value * (d + d2);
340 case e_last:return e->value * d2;
341 case e_st : {
342 int index = av_clip(d, 0, VARS-1);
343 p->prng_state[index].counter = 0;
344 return e->value * (p->var[index]= d2);
345 }
346 case e_hypot:return e->value * hypot(d, d2);
347 case e_atan2:return e->value * atan2(d, d2);
348 case e_bitand: return isnan(d) || isnan(d2) ? NAN : e->value * ((long int)d & (long int)d2);
349 case e_bitor: return isnan(d) || isnan(d2) ? NAN : e->value * ((long int)d | (long int)d2);
350 }
351 }
352 }
353 return NAN;
354 }
355
356 static int parse_expr(AVExpr **e, Parser *p);
357
358 void av_expr_free(AVExpr *e)
359 {
360 if (!e) return;
361 av_expr_free(e->param[0]);
362 av_expr_free(e->param[1]);
363 av_expr_free(e->param[2]);
364 av_freep(&e->var);
365 av_freep(&e->prng_state);
366 av_freep(&e);
367 }
368
369 static int parse_primary(AVExpr **e, Parser *p)
370 {
371 AVExpr *d = av_mallocz(sizeof(AVExpr));
372 char *next = p->s, *s0 = p->s;
373 int ret, i;
374
375 if (!d)
376 return AVERROR(ENOMEM);
377
378 /* number */
379 d->value = av_strtod(p->s, &next);
380 if (next != p->s) {
381 d->type = e_value;
382 p->s= next;
383 *e = d;
384 return 0;
385 }
386 d->value = 1;
387
388 /* named constants */
389 for (i=0; p->const_names && p->const_names[i]; i++) {
390 if (strmatch(p->s, p->const_names[i])) {
391 p->s+= strlen(p->const_names[i]);
392 d->type = e_const;
393 d->const_index = i;
394 *e = d;
395 return 0;
396 }
397 }
398 for (i = 0; i < FF_ARRAY_ELEMS(constants); i++) {
399 if (strmatch(p->s, constants[i].name)) {
400 p->s += strlen(constants[i].name);
401 d->type = e_value;
402 d->value = constants[i].value;
403 *e = d;
404 return 0;
405 }
406 }
407
408 p->s= strchr(p->s, '(');
409 if (!p->s) {
410 av_log(p, AV_LOG_ERROR, "Undefined constant or missing '(' in '%s'\n", s0);
411 p->s= next;
412 av_expr_free(d);
413 return AVERROR(EINVAL);
414 }
415 p->s++; // "("
416 if (*next == '(') { // special case do-nothing
417 av_freep(&d);
418 if ((ret = parse_expr(&d, p)) < 0)
419 return ret;
420 if (p->s[0] != ')') {
421 av_log(p, AV_LOG_ERROR, "Missing ')' in '%s'\n", s0);
422 av_expr_free(d);
423 return AVERROR(EINVAL);
424 }
425 p->s++; // ")"
426 *e = d;
427 return 0;
428 }
429 if ((ret = parse_expr(&(d->param[0]), p)) < 0) {
430 av_expr_free(d);
431 return ret;
432 }
433 if (p->s[0]== ',') {
434 p->s++; // ","
435 parse_expr(&d->param[1], p);
436 }
437 if (p->s[0]== ',') {
438 p->s++; // ","
439 parse_expr(&d->param[2], p);
440 }
441 if (p->s[0] != ')') {
442 av_log(p, AV_LOG_ERROR, "Missing ')' or too many args in '%s'\n", s0);
443 av_expr_free(d);
444 return AVERROR(EINVAL);
445 }
446 p->s++; // ")"
447
448 d->type = e_func0;
449 if (strmatch(next, "sinh" )) d->a.func0 = sinh;
450 else if (strmatch(next, "cosh" )) d->a.func0 = cosh;
451 else if (strmatch(next, "tanh" )) d->a.func0 = tanh;
452 else if (strmatch(next, "sin" )) d->a.func0 = sin;
453 else if (strmatch(next, "cos" )) d->a.func0 = cos;
454 else if (strmatch(next, "tan" )) d->a.func0 = tan;
455 else if (strmatch(next, "atan" )) d->a.func0 = atan;
456 else if (strmatch(next, "asin" )) d->a.func0 = asin;
457 else if (strmatch(next, "acos" )) d->a.func0 = acos;
458 else if (strmatch(next, "exp" )) d->a.func0 = exp;
459 else if (strmatch(next, "log" )) d->a.func0 = log;
460 else if (strmatch(next, "abs" )) d->a.func0 = fabs;
461 else if (strmatch(next, "time" )) d->a.func0 = etime;
462 else if (strmatch(next, "squish")) d->type = e_squish;
463 else if (strmatch(next, "gauss" )) d->type = e_gauss;
464 else if (strmatch(next, "mod" )) d->type = e_mod;
465 else if (strmatch(next, "max" )) d->type = e_max;
466 else if (strmatch(next, "min" )) d->type = e_min;
467 else if (strmatch(next, "eq" )) d->type = e_eq;
468 else if (strmatch(next, "gte" )) d->type = e_gte;
469 else if (strmatch(next, "gt" )) d->type = e_gt;
470 else if (strmatch(next, "lte" )) d->type = e_lte;
471 else if (strmatch(next, "lt" )) d->type = e_lt;
472 else if (strmatch(next, "ld" )) d->type = e_ld;
473 else if (strmatch(next, "isnan" )) d->type = e_isnan;
474 else if (strmatch(next, "isinf" )) d->type = e_isinf;
475 else if (strmatch(next, "st" )) d->type = e_st;
476 else if (strmatch(next, "while" )) d->type = e_while;
477 else if (strmatch(next, "taylor")) d->type = e_taylor;
478 else if (strmatch(next, "root" )) d->type = e_root;
479 else if (strmatch(next, "floor" )) d->type = e_floor;
480 else if (strmatch(next, "ceil" )) d->type = e_ceil;
481 else if (strmatch(next, "trunc" )) d->type = e_trunc;
482 else if (strmatch(next, "round" )) d->type = e_round;
483 else if (strmatch(next, "sqrt" )) d->type = e_sqrt;
484 else if (strmatch(next, "not" )) d->type = e_not;
485 else if (strmatch(next, "pow" )) d->type = e_pow;
486 else if (strmatch(next, "print" )) d->type = e_print;
487 else if (strmatch(next, "random")) d->type = e_random;
488 else if (strmatch(next, "randomi")) d->type = e_randomi;
489 else if (strmatch(next, "hypot" )) d->type = e_hypot;
490 else if (strmatch(next, "gcd" )) d->type = e_gcd;
491 else if (strmatch(next, "if" )) d->type = e_if;
492 else if (strmatch(next, "ifnot" )) d->type = e_ifnot;
493 else if (strmatch(next, "bitand")) d->type = e_bitand;
494 else if (strmatch(next, "bitor" )) d->type = e_bitor;
495 else if (strmatch(next, "between"))d->type = e_between;
496 else if (strmatch(next, "clip" )) d->type = e_clip;
497 else if (strmatch(next, "atan2" )) d->type = e_atan2;
498 else if (strmatch(next, "lerp" )) d->type = e_lerp;
499 else if (strmatch(next, "sgn" )) d->type = e_sgn;
500 else {
501 for (i=0; p->func1_names && p->func1_names[i]; i++) {
502 if (strmatch(next, p->func1_names[i])) {
503 d->a.func1 = p->funcs1[i];
504 d->type = e_func1;
505 d->const_index = i;
506 *e = d;
507 return 0;
508 }
509 }
510
511 for (i=0; p->func2_names && p->func2_names[i]; i++) {
512 if (strmatch(next, p->func2_names[i])) {
513 d->a.func2 = p->funcs2[i];
514 d->type = e_func2;
515 d->const_index = i;
516 *e = d;
517 return 0;
518 }
519 }
520
521 av_log(p, AV_LOG_ERROR, "Unknown function in '%s'\n", s0);
522 av_expr_free(d);
523 return AVERROR(EINVAL);
524 }
525
526 *e = d;
527 return 0;
528 }
529
530 static AVExpr *make_eval_expr(int type, int value, AVExpr *p0, AVExpr *p1)
531 {
532 AVExpr *e = av_mallocz(sizeof(AVExpr));
533 if (!e)
534 return NULL;
535 e->type =type ;
536 e->value =value ;
537 e->param[0] =p0 ;
538 e->param[1] =p1 ;
539 return e;
540 }
541
542 static int parse_pow(AVExpr **e, Parser *p, int *sign)
543 {
544 *sign= (*p->s == '+') - (*p->s == '-');
545 p->s += *sign&1;
546 return parse_primary(e, p);
547 }
548
549 static int parse_dB(AVExpr **e, Parser *p, int *sign)
550 {
551 /* do not filter out the negative sign when parsing a dB value.
552 for example, -3dB is not the same as -(3dB) */
553 if (*p->s == '-') {
554 char *next;
555 av_unused double ignored = strtod(p->s, &next);
556 if (next != p->s && next[0] == 'd' && next[1] == 'B') {
557 *sign = 0;
558 return parse_primary(e, p);
559 }
560 }
561 return parse_pow(e, p, sign);
562 }
563
564 static int parse_factor(AVExpr **e, Parser *p)
565 {
566 int sign, sign2, ret;
567 AVExpr *e0, *e1, *e2;
568 if ((ret = parse_dB(&e0, p, &sign)) < 0)
569 return ret;
570 while(p->s[0]=='^'){
571 e1 = e0;
572 p->s++;
573 if ((ret = parse_dB(&e2, p, &sign2)) < 0) {
574 av_expr_free(e1);
575 return ret;
576 }
577 e0 = make_eval_expr(e_pow, 1, e1, e2);
578 if (!e0) {
579 av_expr_free(e1);
580 av_expr_free(e2);
581 return AVERROR(ENOMEM);
582 }
583 if (e0->param[1]) e0->param[1]->value *= (sign2|1);
584 }
585 if (e0) e0->value *= (sign|1);
586
587 *e = e0;
588 return 0;
589 }
590
591 static int parse_term(AVExpr **e, Parser *p)
592 {
593 int ret;
594 AVExpr *e0, *e1, *e2;
595 if ((ret = parse_factor(&e0, p)) < 0)
596 return ret;
597 while (p->s[0]=='*' || p->s[0]=='/') {
598 int c= *p->s++;
599 e1 = e0;
600 if ((ret = parse_factor(&e2, p)) < 0) {
601 av_expr_free(e1);
602 return ret;
603 }
604 e0 = make_eval_expr(c == '*' ? e_mul : e_div, 1, e1, e2);
605 if (!e0) {
606 av_expr_free(e1);
607 av_expr_free(e2);
608 return AVERROR(ENOMEM);
609 }
610 }
611 *e = e0;
612 return 0;
613 }
614
615 static int parse_subexpr(AVExpr **e, Parser *p)
616 {
617 int ret;
618 AVExpr *e0, *e1, *e2;
619 if ((ret = parse_term(&e0, p)) < 0)
620 return ret;
621 while (*p->s == '+' || *p->s == '-') {
622 e1 = e0;
623 if ((ret = parse_term(&e2, p)) < 0) {
624 av_expr_free(e1);
625 return ret;
626 }
627 e0 = make_eval_expr(e_add, 1, e1, e2);
628 if (!e0) {
629 av_expr_free(e1);
630 av_expr_free(e2);
631 return AVERROR(ENOMEM);
632 }
633 };
634
635 *e = e0;
636 return 0;
637 }
638
639 static int parse_expr(AVExpr **e, Parser *p)
640 {
641 int ret;
642 AVExpr *e0, *e1, *e2;
643 if (p->stack_index <= 0) //protect against stack overflows
644 return AVERROR(EINVAL);
645 p->stack_index--;
646
647 if ((ret = parse_subexpr(&e0, p)) < 0)
648 return ret;
649 while (*p->s == ';') {
650 p->s++;
651 e1 = e0;
652 if ((ret = parse_subexpr(&e2, p)) < 0) {
653 av_expr_free(e1);
654 return ret;
655 }
656 e0 = make_eval_expr(e_last, 1, e1, e2);
657 if (!e0) {
658 av_expr_free(e1);
659 av_expr_free(e2);
660 return AVERROR(ENOMEM);
661 }
662 };
663
664 p->stack_index++;
665 *e = e0;
666 return 0;
667 }
668
669 static int verify_expr(AVExpr *e)
670 {
671 if (!e) return 0;
672 switch (e->type) {
673 case e_value:
674 case e_const: return 1;
675 case e_func0:
676 case e_func1:
677 case e_squish:
678 case e_ld:
679 case e_gauss:
680 case e_isnan:
681 case e_isinf:
682 case e_floor:
683 case e_ceil:
684 case e_trunc:
685 case e_round:
686 case e_sqrt:
687 case e_not:
688 case e_random:
689 case e_sgn:
690 return verify_expr(e->param[0]) && !e->param[1];
691 case e_print:
692 return verify_expr(e->param[0])
693 && (!e->param[1] || verify_expr(e->param[1]));
694 case e_if:
695 case e_ifnot:
696 case e_taylor:
697 return verify_expr(e->param[0]) && verify_expr(e->param[1])
698 && (!e->param[2] || verify_expr(e->param[2]));
699 case e_between:
700 case e_clip:
701 case e_lerp:
702 case e_randomi:
703 return verify_expr(e->param[0]) &&
704 verify_expr(e->param[1]) &&
705 verify_expr(e->param[2]);
706 default: return verify_expr(e->param[0]) && verify_expr(e->param[1]) && !e->param[2];
707 }
708 }
709
710 int av_expr_parse(AVExpr **expr, const char *s,
711 const char * const *const_names,
712 const char * const *func1_names, double (* const *funcs1)(void *, double),
713 const char * const *func2_names, double (* const *funcs2)(void *, double, double),
714 int log_offset, void *log_ctx)
715 {
716 Parser p = { 0 };
717 AVExpr *e = NULL;
718 char *w = av_malloc(strlen(s) + 1);
719 char *wp = w;
720 const char *s0 = s;
721 int ret = 0;
722
723 if (!w)
724 return AVERROR(ENOMEM);
725
726 while (*s)
727 if (!av_isspace(*s++)) *wp++ = s[-1];
728 *wp++ = 0;
729
730 p.class = &eval_class;
731 p.stack_index=100;
732 p.s= w;
733 p.const_names = const_names;
734 p.funcs1 = funcs1;
735 p.func1_names = func1_names;
736 p.funcs2 = funcs2;
737 p.func2_names = func2_names;
738 p.log_offset = log_offset;
739 p.log_ctx = log_ctx;
740
741 if ((ret = parse_expr(&e, &p)) < 0)
742 goto end;
743 if (*p.s) {
744 av_log(&p, AV_LOG_ERROR, "Invalid chars '%s' at the end of expression '%s'\n", p.s, s0);
745 ret = AVERROR(EINVAL);
746 goto end;
747 }
748 if (!verify_expr(e)) {
749 ret = AVERROR(EINVAL);
750 goto end;
751 }
752 e->var= av_mallocz(sizeof(double) *VARS);
753 e->prng_state = av_mallocz(sizeof(*e->prng_state) *VARS);
754 if (!e->var || !e->prng_state) {
755 ret = AVERROR(ENOMEM);
756 goto end;
757 }
758 *expr = e;
759 e = NULL;
760 end:
761 av_expr_free(e);
762 av_free(w);
763 return ret;
764 }
765
766 static int expr_count(AVExpr *e, unsigned *counter, int size, int type)
767 {
768 int i;
769
770 if (!e || !counter || !size)
771 return AVERROR(EINVAL);
772
773 for (i = 0; e->type != type && i < 3 && e->param[i]; i++)
774 expr_count(e->param[i], counter, size, type);
775
776 if (e->type == type && e->const_index < size)
777 counter[e->const_index]++;
778
779 return 0;
780 }
781
782 int av_expr_count_vars(AVExpr *e, unsigned *counter, int size)
783 {
784 return expr_count(e, counter, size, e_const);
785 }
786
787 int av_expr_count_func(AVExpr *e, unsigned *counter, int size, int arg)
788 {
789 return expr_count(e, counter, size, ((int[]){e_const, e_func1, e_func2})[arg]);
790 }
791
792 double av_expr_eval(AVExpr *e, const double *const_values, void *opaque)
793 {
794 Parser p = {
795 .class = &eval_class,
796 .const_values = const_values,
797 .opaque = opaque,
798 .var = e->var,
799 .prng_state = e->prng_state,
800 };
801
802 return eval_expr(&p, e);
803 }
804
805 int av_expr_parse_and_eval(double *d, const char *s,
806 const char * const *const_names, const double *const_values,
807 const char * const *func1_names, double (* const *funcs1)(void *, double),
808 const char * const *func2_names, double (* const *funcs2)(void *, double, double),
809 void *opaque, int log_offset, void *log_ctx)
810 {
811 AVExpr *e = NULL;
812 int ret = av_expr_parse(&e, s, const_names, func1_names, funcs1, func2_names, funcs2, log_offset, log_ctx);
813
814 if (ret < 0) {
815 *d = NAN;
816 return ret;
817 }
818 *d = av_expr_eval(e, const_values, opaque);
819 av_expr_free(e);
820 return isnan(*d) ? AVERROR(EINVAL) : 0;
821 }
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