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 "internal.h"
36 #include "log.h"
37 #include "mathematics.h"
38 #include "time.h"
39 #include "avstring.h"
40 #include "timer.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 } Parser;
59
60 static const AVClass eval_class = {
61 .class_name = "Eval",
62 .item_name = av_default_item_name,
63 .option = NULL,
64 .version = LIBAVUTIL_VERSION_INT,
65 .log_level_offset_offset = offsetof(Parser, log_offset),
66 .parent_log_context_offset = offsetof(Parser, log_ctx),
67 };
68
69 static const struct {
70 double bin_val;
71 double dec_val;
72 int8_t exp;
73 } si_prefixes['z' - 'E' + 1] = {
74 ['y'-'E']= { 8.271806125530276749e-25, 1e-24, -24 },
75 ['z'-'E']= { 8.4703294725430034e-22, 1e-21, -21 },
76 ['a'-'E']= { 8.6736173798840355e-19, 1e-18, -18 },
77 ['f'-'E']= { 8.8817841970012523e-16, 1e-15, -15 },
78 ['p'-'E']= { 9.0949470177292824e-13, 1e-12, -12 },
79 ['n'-'E']= { 9.3132257461547852e-10, 1e-9, -9 },
80 ['u'-'E']= { 9.5367431640625e-7, 1e-6, -6 },
81 ['m'-'E']= { 9.765625e-4, 1e-3, -3 },
82 ['c'-'E']= { 9.8431332023036951e-3, 1e-2, -2 },
83 ['d'-'E']= { 9.921256574801246e-2, 1e-1, -1 },
84 ['h'-'E']= { 1.0159366732596479e2, 1e2, 2 },
85 ['k'-'E']= { 1.024e3, 1e3, 3 },
86 ['K'-'E']= { 1.024e3, 1e3, 3 },
87 ['M'-'E']= { 1.048576e6, 1e6, 6 },
88 ['G'-'E']= { 1.073741824e9, 1e9, 9 },
89 ['T'-'E']= { 1.099511627776e12, 1e12, 12 },
90 ['P'-'E']= { 1.125899906842624e15, 1e15, 15 },
91 ['E'-'E']= { 1.152921504606847e18, 1e18, 18 },
92 ['Z'-'E']= { 1.1805916207174113e21, 1e21, 21 },
93 ['Y'-'E']= { 1.2089258196146292e24, 1e24, 24 },
94 };
95
96 static const struct {
97 const char *name;
98 double value;
99 } constants[] = {
100 { "E", M_E },
101 { "PI", M_PI },
102 { "PHI", M_PHI },
103 { "QP2LAMBDA", FF_QP2LAMBDA },
104 };
105
av_strtod(const char * numstr,char ** tail)106 double av_strtod(const char *numstr, char **tail)
107 {
108 double d;
109 char *next;
110 if(numstr[0]=='0' && (numstr[1]|0x20)=='x') {
111 d = strtoul(numstr, &next, 16);
112 } else
113 d = strtod(numstr, &next);
114 /* if parsing succeeded, check for and interpret postfixes */
115 if (next!=numstr) {
116 if (next[0] == 'd' && next[1] == 'B') {
117 /* treat dB as decibels instead of decibytes */
118 d = ff_exp10(d / 20);
119 next += 2;
120 } else if (*next >= 'E' && *next <= 'z') {
121 int e= si_prefixes[*next - 'E'].exp;
122 if (e) {
123 if (next[1] == 'i') {
124 d*= si_prefixes[*next - 'E'].bin_val;
125 next+=2;
126 } else {
127 d*= si_prefixes[*next - 'E'].dec_val;
128 next++;
129 }
130 }
131 }
132
133 if (*next=='B') {
134 d*=8;
135 next++;
136 }
137 }
138 /* if requested, fill in tail with the position after the last parsed
139 character */
140 if (tail)
141 *tail = next;
142 return d;
143 }
144
145 #define IS_IDENTIFIER_CHAR(c) ((c) - '0' <= 9U || (c) - 'a' <= 25U || (c) - 'A' <= 25U || (c) == '_')
146
strmatch(const char * s,const char * prefix)147 static int strmatch(const char *s, const char *prefix)
148 {
149 int i;
150 for (i=0; prefix[i]; i++) {
151 if (prefix[i] != s[i]) return 0;
152 }
153 /* return 1 only if the s identifier is terminated */
154 return !IS_IDENTIFIER_CHAR(s[i]);
155 }
156
157 struct AVExpr {
158 enum {
159 e_value, e_const, e_func0, e_func1, e_func2,
160 e_squish, e_gauss, e_ld, e_isnan, e_isinf,
161 e_mod, e_max, e_min, e_eq, e_gt, e_gte, e_lte, e_lt,
162 e_pow, e_mul, e_div, e_add,
163 e_last, e_st, e_while, e_taylor, e_root, e_floor, e_ceil, e_trunc, e_round,
164 e_sqrt, e_not, e_random, e_hypot, e_gcd,
165 e_if, e_ifnot, e_print, e_bitand, e_bitor, e_between, e_clip, e_atan2, e_lerp,
166 e_sgn,
167 } type;
168 double value; // is sign in other types
169 int const_index;
170 union {
171 double (*func0)(double);
172 double (*func1)(void *, double);
173 double (*func2)(void *, double, double);
174 } a;
175 struct AVExpr *param[3];
176 double *var;
177 };
178
etime(double v)179 static double etime(double v)
180 {
181 return av_gettime() * 0.000001;
182 }
183
eval_expr(Parser * p,AVExpr * e)184 static double eval_expr(Parser *p, AVExpr *e)
185 {
186 switch (e->type) {
187 case e_value: return e->value;
188 case e_const: return e->value * p->const_values[e->const_index];
189 case e_func0: return e->value * e->a.func0(eval_expr(p, e->param[0]));
190 case e_func1: return e->value * e->a.func1(p->opaque, eval_expr(p, e->param[0]));
191 case e_func2: return e->value * e->a.func2(p->opaque, eval_expr(p, e->param[0]), eval_expr(p, e->param[1]));
192 case e_squish: return 1/(1+exp(4*eval_expr(p, e->param[0])));
193 case e_gauss: { double d = eval_expr(p, e->param[0]); return exp(-d*d/2)/sqrt(2*M_PI); }
194 case e_ld: return e->value * p->var[av_clip(eval_expr(p, e->param[0]), 0, VARS-1)];
195 case e_isnan: return e->value * !!isnan(eval_expr(p, e->param[0]));
196 case e_isinf: return e->value * !!isinf(eval_expr(p, e->param[0]));
197 case e_floor: return e->value * floor(eval_expr(p, e->param[0]));
198 case e_ceil : return e->value * ceil (eval_expr(p, e->param[0]));
199 case e_trunc: return e->value * trunc(eval_expr(p, e->param[0]));
200 case e_round: return e->value * round(eval_expr(p, e->param[0]));
201 case e_sgn: return e->value * FFDIFFSIGN(eval_expr(p, e->param[0]), 0);
202 case e_sqrt: return e->value * sqrt (eval_expr(p, e->param[0]));
203 case e_not: return e->value * (eval_expr(p, e->param[0]) == 0);
204 case e_if: return e->value * (eval_expr(p, e->param[0]) ? eval_expr(p, e->param[1]) :
205 e->param[2] ? eval_expr(p, e->param[2]) : 0);
206 case e_ifnot: 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_clip: {
209 double x = eval_expr(p, e->param[0]);
210 double min = eval_expr(p, e->param[1]), max = eval_expr(p, e->param[2]);
211 if (isnan(min) || isnan(max) || isnan(x) || min > max)
212 return NAN;
213 return e->value * av_clipd(eval_expr(p, e->param[0]), min, max);
214 }
215 case e_between: {
216 double d = eval_expr(p, e->param[0]);
217 return e->value * (d >= eval_expr(p, e->param[1]) &&
218 d <= eval_expr(p, e->param[2]));
219 }
220 case e_lerp: {
221 double v0 = eval_expr(p, e->param[0]);
222 double v1 = eval_expr(p, e->param[1]);
223 double f = eval_expr(p, e->param[2]);
224 return v0 + (v1 - v0) * f;
225 }
226 case e_print: {
227 double x = eval_expr(p, e->param[0]);
228 int level = e->param[1] ? av_clip(eval_expr(p, e->param[1]), INT_MIN, INT_MAX) : AV_LOG_INFO;
229 av_log(p, level, "%f\n", x);
230 return x;
231 }
232 case e_random:{
233 int idx= av_clip(eval_expr(p, e->param[0]), 0, VARS-1);
234 uint64_t r= isnan(p->var[idx]) ? 0 : p->var[idx];
235 r= r*1664525+1013904223;
236 p->var[idx]= r;
237 return e->value * (r * (1.0/UINT64_MAX));
238 }
239 case e_while: {
240 double d = NAN;
241 while (eval_expr(p, e->param[0]))
242 d=eval_expr(p, e->param[1]);
243 return d;
244 }
245 case e_taylor: {
246 double t = 1, d = 0, v;
247 double x = eval_expr(p, e->param[1]);
248 int id = e->param[2] ? av_clip(eval_expr(p, e->param[2]), 0, VARS-1) : 0;
249 int i;
250 double var0 = p->var[id];
251 for(i=0; i<1000; i++) {
252 double ld = d;
253 p->var[id] = i;
254 v = eval_expr(p, e->param[0]);
255 d += t*v;
256 if(ld==d && v)
257 break;
258 t *= x / (i+1);
259 }
260 p->var[id] = var0;
261 return d;
262 }
263 case e_root: {
264 int i, j;
265 double low = -1, high = -1, v, low_v = -DBL_MAX, high_v = DBL_MAX;
266 double var0 = p->var[0];
267 double x_max = eval_expr(p, e->param[1]);
268 for(i=-1; i<1024; i++) {
269 if(i<255) {
270 p->var[0] = ff_reverse[i&255]*x_max/255;
271 } else {
272 p->var[0] = x_max*pow(0.9, i-255);
273 if (i&1) p->var[0] *= -1;
274 if (i&2) p->var[0] += low;
275 else p->var[0] += high;
276 }
277 v = eval_expr(p, e->param[0]);
278 if (v<=0 && v>low_v) {
279 low = p->var[0];
280 low_v = v;
281 }
282 if (v>=0 && v<high_v) {
283 high = p->var[0];
284 high_v = v;
285 }
286 if (low>=0 && high>=0){
287 for (j=0; j<1000; j++) {
288 p->var[0] = (low+high)*0.5;
289 if (low == p->var[0] || high == p->var[0])
290 break;
291 v = eval_expr(p, e->param[0]);
292 if (v<=0) low = p->var[0];
293 if (v>=0) high= p->var[0];
294 if (isnan(v)) {
295 low = high = v;
296 break;
297 }
298 }
299 break;
300 }
301 }
302 p->var[0] = var0;
303 return -low_v<high_v ? low : high;
304 }
305 default: {
306 double d = eval_expr(p, e->param[0]);
307 double d2 = eval_expr(p, e->param[1]);
308 switch (e->type) {
309 case e_mod: return e->value * (d - floor(d2 ? d / d2 : d * INFINITY) * d2);
310 case e_gcd: return e->value * av_gcd(d,d2);
311 case e_max: return e->value * (d > d2 ? d : d2);
312 case e_min: return e->value * (d < d2 ? d : d2);
313 case e_eq: return e->value * (d == d2 ? 1.0 : 0.0);
314 case e_gt: return e->value * (d > d2 ? 1.0 : 0.0);
315 case e_gte: return e->value * (d >= d2 ? 1.0 : 0.0);
316 case e_lt: return e->value * (d < d2 ? 1.0 : 0.0);
317 case e_lte: return e->value * (d <= d2 ? 1.0 : 0.0);
318 case e_pow: return e->value * pow(d, d2);
319 case e_mul: return e->value * (d * d2);
320 case e_div: return e->value * (d2 ? (d / d2) : d * INFINITY);
321 case e_add: return e->value * (d + d2);
322 case e_last:return e->value * d2;
323 case e_st : return e->value * (p->var[av_clip(d, 0, VARS-1)]= d2);
324 case e_hypot:return e->value * hypot(d, d2);
325 case e_atan2:return e->value * atan2(d, d2);
326 case e_bitand: return isnan(d) || isnan(d2) ? NAN : e->value * ((long int)d & (long int)d2);
327 case e_bitor: return isnan(d) || isnan(d2) ? NAN : e->value * ((long int)d | (long int)d2);
328 }
329 }
330 }
331 return NAN;
332 }
333
334 static int parse_expr(AVExpr **e, Parser *p);
335
av_expr_free(AVExpr * e)336 void av_expr_free(AVExpr *e)
337 {
338 if (!e) return;
339 av_expr_free(e->param[0]);
340 av_expr_free(e->param[1]);
341 av_expr_free(e->param[2]);
342 av_freep(&e->var);
343 av_freep(&e);
344 }
345
parse_primary(AVExpr ** e,Parser * p)346 static int parse_primary(AVExpr **e, Parser *p)
347 {
348 AVExpr *d = av_mallocz(sizeof(AVExpr));
349 char *next = p->s, *s0 = p->s;
350 int ret, i;
351
352 if (!d)
353 return AVERROR(ENOMEM);
354
355 /* number */
356 d->value = av_strtod(p->s, &next);
357 if (next != p->s) {
358 d->type = e_value;
359 p->s= next;
360 *e = d;
361 return 0;
362 }
363 d->value = 1;
364
365 /* named constants */
366 for (i=0; p->const_names && p->const_names[i]; i++) {
367 if (strmatch(p->s, p->const_names[i])) {
368 p->s+= strlen(p->const_names[i]);
369 d->type = e_const;
370 d->const_index = i;
371 *e = d;
372 return 0;
373 }
374 }
375 for (i = 0; i < FF_ARRAY_ELEMS(constants); i++) {
376 if (strmatch(p->s, constants[i].name)) {
377 p->s += strlen(constants[i].name);
378 d->type = e_value;
379 d->value = constants[i].value;
380 *e = d;
381 return 0;
382 }
383 }
384
385 p->s= strchr(p->s, '(');
386 if (!p->s) {
387 av_log(p, AV_LOG_ERROR, "Undefined constant or missing '(' in '%s'\n", s0);
388 p->s= next;
389 av_expr_free(d);
390 return AVERROR(EINVAL);
391 }
392 p->s++; // "("
393 if (*next == '(') { // special case do-nothing
394 av_freep(&d);
395 if ((ret = parse_expr(&d, p)) < 0)
396 return ret;
397 if (p->s[0] != ')') {
398 av_log(p, AV_LOG_ERROR, "Missing ')' in '%s'\n", s0);
399 av_expr_free(d);
400 return AVERROR(EINVAL);
401 }
402 p->s++; // ")"
403 *e = d;
404 return 0;
405 }
406 if ((ret = parse_expr(&(d->param[0]), p)) < 0) {
407 av_expr_free(d);
408 return ret;
409 }
410 if (p->s[0]== ',') {
411 p->s++; // ","
412 parse_expr(&d->param[1], p);
413 }
414 if (p->s[0]== ',') {
415 p->s++; // ","
416 parse_expr(&d->param[2], p);
417 }
418 if (p->s[0] != ')') {
419 av_log(p, AV_LOG_ERROR, "Missing ')' or too many args in '%s'\n", s0);
420 av_expr_free(d);
421 return AVERROR(EINVAL);
422 }
423 p->s++; // ")"
424
425 d->type = e_func0;
426 if (strmatch(next, "sinh" )) d->a.func0 = sinh;
427 else if (strmatch(next, "cosh" )) d->a.func0 = cosh;
428 else if (strmatch(next, "tanh" )) d->a.func0 = tanh;
429 else if (strmatch(next, "sin" )) d->a.func0 = sin;
430 else if (strmatch(next, "cos" )) d->a.func0 = cos;
431 else if (strmatch(next, "tan" )) d->a.func0 = tan;
432 else if (strmatch(next, "atan" )) d->a.func0 = atan;
433 else if (strmatch(next, "asin" )) d->a.func0 = asin;
434 else if (strmatch(next, "acos" )) d->a.func0 = acos;
435 else if (strmatch(next, "exp" )) d->a.func0 = exp;
436 else if (strmatch(next, "log" )) d->a.func0 = log;
437 else if (strmatch(next, "abs" )) d->a.func0 = fabs;
438 else if (strmatch(next, "time" )) d->a.func0 = etime;
439 else if (strmatch(next, "squish")) d->type = e_squish;
440 else if (strmatch(next, "gauss" )) d->type = e_gauss;
441 else if (strmatch(next, "mod" )) d->type = e_mod;
442 else if (strmatch(next, "max" )) d->type = e_max;
443 else if (strmatch(next, "min" )) d->type = e_min;
444 else if (strmatch(next, "eq" )) d->type = e_eq;
445 else if (strmatch(next, "gte" )) d->type = e_gte;
446 else if (strmatch(next, "gt" )) d->type = e_gt;
447 else if (strmatch(next, "lte" )) d->type = e_lte;
448 else if (strmatch(next, "lt" )) d->type = e_lt;
449 else if (strmatch(next, "ld" )) d->type = e_ld;
450 else if (strmatch(next, "isnan" )) d->type = e_isnan;
451 else if (strmatch(next, "isinf" )) d->type = e_isinf;
452 else if (strmatch(next, "st" )) d->type = e_st;
453 else if (strmatch(next, "while" )) d->type = e_while;
454 else if (strmatch(next, "taylor")) d->type = e_taylor;
455 else if (strmatch(next, "root" )) d->type = e_root;
456 else if (strmatch(next, "floor" )) d->type = e_floor;
457 else if (strmatch(next, "ceil" )) d->type = e_ceil;
458 else if (strmatch(next, "trunc" )) d->type = e_trunc;
459 else if (strmatch(next, "round" )) d->type = e_round;
460 else if (strmatch(next, "sqrt" )) d->type = e_sqrt;
461 else if (strmatch(next, "not" )) d->type = e_not;
462 else if (strmatch(next, "pow" )) d->type = e_pow;
463 else if (strmatch(next, "print" )) d->type = e_print;
464 else if (strmatch(next, "random")) d->type = e_random;
465 else if (strmatch(next, "hypot" )) d->type = e_hypot;
466 else if (strmatch(next, "gcd" )) d->type = e_gcd;
467 else if (strmatch(next, "if" )) d->type = e_if;
468 else if (strmatch(next, "ifnot" )) d->type = e_ifnot;
469 else if (strmatch(next, "bitand")) d->type = e_bitand;
470 else if (strmatch(next, "bitor" )) d->type = e_bitor;
471 else if (strmatch(next, "between"))d->type = e_between;
472 else if (strmatch(next, "clip" )) d->type = e_clip;
473 else if (strmatch(next, "atan2" )) d->type = e_atan2;
474 else if (strmatch(next, "lerp" )) d->type = e_lerp;
475 else if (strmatch(next, "sgn" )) d->type = e_sgn;
476 else {
477 for (i=0; p->func1_names && p->func1_names[i]; i++) {
478 if (strmatch(next, p->func1_names[i])) {
479 d->a.func1 = p->funcs1[i];
480 d->type = e_func1;
481 d->const_index = i;
482 *e = d;
483 return 0;
484 }
485 }
486
487 for (i=0; p->func2_names && p->func2_names[i]; i++) {
488 if (strmatch(next, p->func2_names[i])) {
489 d->a.func2 = p->funcs2[i];
490 d->type = e_func2;
491 d->const_index = i;
492 *e = d;
493 return 0;
494 }
495 }
496
497 av_log(p, AV_LOG_ERROR, "Unknown function in '%s'\n", s0);
498 av_expr_free(d);
499 return AVERROR(EINVAL);
500 }
501
502 *e = d;
503 return 0;
504 }
505
make_eval_expr(int type,int value,AVExpr * p0,AVExpr * p1)506 static AVExpr *make_eval_expr(int type, int value, AVExpr *p0, AVExpr *p1)
507 {
508 AVExpr *e = av_mallocz(sizeof(AVExpr));
509 if (!e)
510 return NULL;
511 e->type =type ;
512 e->value =value ;
513 e->param[0] =p0 ;
514 e->param[1] =p1 ;
515 return e;
516 }
517
parse_pow(AVExpr ** e,Parser * p,int * sign)518 static int parse_pow(AVExpr **e, Parser *p, int *sign)
519 {
520 *sign= (*p->s == '+') - (*p->s == '-');
521 p->s += *sign&1;
522 return parse_primary(e, p);
523 }
524
parse_dB(AVExpr ** e,Parser * p,int * sign)525 static int parse_dB(AVExpr **e, Parser *p, int *sign)
526 {
527 /* do not filter out the negative sign when parsing a dB value.
528 for example, -3dB is not the same as -(3dB) */
529 if (*p->s == '-') {
530 char *next;
531 double av_unused ignored = strtod(p->s, &next);
532 if (next != p->s && next[0] == 'd' && next[1] == 'B') {
533 *sign = 0;
534 return parse_primary(e, p);
535 }
536 }
537 return parse_pow(e, p, sign);
538 }
539
parse_factor(AVExpr ** e,Parser * p)540 static int parse_factor(AVExpr **e, Parser *p)
541 {
542 int sign, sign2, ret;
543 AVExpr *e0, *e1, *e2;
544 if ((ret = parse_dB(&e0, p, &sign)) < 0)
545 return ret;
546 while(p->s[0]=='^'){
547 e1 = e0;
548 p->s++;
549 if ((ret = parse_dB(&e2, p, &sign2)) < 0) {
550 av_expr_free(e1);
551 return ret;
552 }
553 e0 = make_eval_expr(e_pow, 1, e1, e2);
554 if (!e0) {
555 av_expr_free(e1);
556 av_expr_free(e2);
557 return AVERROR(ENOMEM);
558 }
559 if (e0->param[1]) e0->param[1]->value *= (sign2|1);
560 }
561 if (e0) e0->value *= (sign|1);
562
563 *e = e0;
564 return 0;
565 }
566
parse_term(AVExpr ** e,Parser * p)567 static int parse_term(AVExpr **e, Parser *p)
568 {
569 int ret;
570 AVExpr *e0, *e1, *e2;
571 if ((ret = parse_factor(&e0, p)) < 0)
572 return ret;
573 while (p->s[0]=='*' || p->s[0]=='/') {
574 int c= *p->s++;
575 e1 = e0;
576 if ((ret = parse_factor(&e2, p)) < 0) {
577 av_expr_free(e1);
578 return ret;
579 }
580 e0 = make_eval_expr(c == '*' ? e_mul : e_div, 1, e1, e2);
581 if (!e0) {
582 av_expr_free(e1);
583 av_expr_free(e2);
584 return AVERROR(ENOMEM);
585 }
586 }
587 *e = e0;
588 return 0;
589 }
590
parse_subexpr(AVExpr ** e,Parser * p)591 static int parse_subexpr(AVExpr **e, Parser *p)
592 {
593 int ret;
594 AVExpr *e0, *e1, *e2;
595 if ((ret = parse_term(&e0, p)) < 0)
596 return ret;
597 while (*p->s == '+' || *p->s == '-') {
598 e1 = e0;
599 if ((ret = parse_term(&e2, p)) < 0) {
600 av_expr_free(e1);
601 return ret;
602 }
603 e0 = make_eval_expr(e_add, 1, e1, e2);
604 if (!e0) {
605 av_expr_free(e1);
606 av_expr_free(e2);
607 return AVERROR(ENOMEM);
608 }
609 };
610
611 *e = e0;
612 return 0;
613 }
614
parse_expr(AVExpr ** e,Parser * p)615 static int parse_expr(AVExpr **e, Parser *p)
616 {
617 int ret;
618 AVExpr *e0, *e1, *e2;
619 if (p->stack_index <= 0) //protect against stack overflows
620 return AVERROR(EINVAL);
621 p->stack_index--;
622
623 if ((ret = parse_subexpr(&e0, p)) < 0)
624 return ret;
625 while (*p->s == ';') {
626 p->s++;
627 e1 = e0;
628 if ((ret = parse_subexpr(&e2, p)) < 0) {
629 av_expr_free(e1);
630 return ret;
631 }
632 e0 = make_eval_expr(e_last, 1, e1, e2);
633 if (!e0) {
634 av_expr_free(e1);
635 av_expr_free(e2);
636 return AVERROR(ENOMEM);
637 }
638 };
639
640 p->stack_index++;
641 *e = e0;
642 return 0;
643 }
644
verify_expr(AVExpr * e)645 static int verify_expr(AVExpr *e)
646 {
647 if (!e) return 0;
648 switch (e->type) {
649 case e_value:
650 case e_const: return 1;
651 case e_func0:
652 case e_func1:
653 case e_squish:
654 case e_ld:
655 case e_gauss:
656 case e_isnan:
657 case e_isinf:
658 case e_floor:
659 case e_ceil:
660 case e_trunc:
661 case e_round:
662 case e_sqrt:
663 case e_not:
664 case e_random:
665 case e_sgn:
666 return verify_expr(e->param[0]) && !e->param[1];
667 case e_print:
668 return verify_expr(e->param[0])
669 && (!e->param[1] || verify_expr(e->param[1]));
670 case e_if:
671 case e_ifnot:
672 case e_taylor:
673 return verify_expr(e->param[0]) && verify_expr(e->param[1])
674 && (!e->param[2] || verify_expr(e->param[2]));
675 case e_between:
676 case e_clip:
677 case e_lerp:
678 return verify_expr(e->param[0]) &&
679 verify_expr(e->param[1]) &&
680 verify_expr(e->param[2]);
681 default: return verify_expr(e->param[0]) && verify_expr(e->param[1]) && !e->param[2];
682 }
683 }
684
av_expr_parse(AVExpr ** expr,const char * s,const char * const * const_names,const char * const * func1_names,double (* const * funcs1)(void *,double),const char * const * func2_names,double (* const * funcs2)(void *,double,double),int log_offset,void * log_ctx)685 int av_expr_parse(AVExpr **expr, const char *s,
686 const char * const *const_names,
687 const char * const *func1_names, double (* const *funcs1)(void *, double),
688 const char * const *func2_names, double (* const *funcs2)(void *, double, double),
689 int log_offset, void *log_ctx)
690 {
691 Parser p = { 0 };
692 AVExpr *e = NULL;
693 char *w = av_malloc(strlen(s) + 1);
694 char *wp = w;
695 const char *s0 = s;
696 int ret = 0;
697
698 if (!w)
699 return AVERROR(ENOMEM);
700
701 while (*s)
702 if (!av_isspace(*s++)) *wp++ = s[-1];
703 *wp++ = 0;
704
705 p.class = &eval_class;
706 p.stack_index=100;
707 p.s= w;
708 p.const_names = const_names;
709 p.funcs1 = funcs1;
710 p.func1_names = func1_names;
711 p.funcs2 = funcs2;
712 p.func2_names = func2_names;
713 p.log_offset = log_offset;
714 p.log_ctx = log_ctx;
715
716 if ((ret = parse_expr(&e, &p)) < 0)
717 goto end;
718 if (*p.s) {
719 av_log(&p, AV_LOG_ERROR, "Invalid chars '%s' at the end of expression '%s'\n", p.s, s0);
720 ret = AVERROR(EINVAL);
721 goto end;
722 }
723 if (!verify_expr(e)) {
724 ret = AVERROR(EINVAL);
725 goto end;
726 }
727 e->var= av_mallocz(sizeof(double) *VARS);
728 if (!e->var) {
729 ret = AVERROR(ENOMEM);
730 goto end;
731 }
732 *expr = e;
733 e = NULL;
734 end:
735 av_expr_free(e);
736 av_free(w);
737 return ret;
738 }
739
expr_count(AVExpr * e,unsigned * counter,int size,int type)740 static int expr_count(AVExpr *e, unsigned *counter, int size, int type)
741 {
742 int i;
743
744 if (!e || !counter || !size)
745 return AVERROR(EINVAL);
746
747 for (i = 0; e->type != type && i < 3 && e->param[i]; i++)
748 expr_count(e->param[i], counter, size, type);
749
750 if (e->type == type && e->const_index < size)
751 counter[e->const_index]++;
752
753 return 0;
754 }
755
av_expr_count_vars(AVExpr * e,unsigned * counter,int size)756 int av_expr_count_vars(AVExpr *e, unsigned *counter, int size)
757 {
758 return expr_count(e, counter, size, e_const);
759 }
760
av_expr_count_func(AVExpr * e,unsigned * counter,int size,int arg)761 int av_expr_count_func(AVExpr *e, unsigned *counter, int size, int arg)
762 {
763 return expr_count(e, counter, size, ((int[]){e_const, e_func1, e_func2})[arg]);
764 }
765
av_expr_eval(AVExpr * e,const double * const_values,void * opaque)766 double av_expr_eval(AVExpr *e, const double *const_values, void *opaque)
767 {
768 Parser p = { 0 };
769 p.var= e->var;
770
771 p.const_values = const_values;
772 p.opaque = opaque;
773 return eval_expr(&p, e);
774 }
775
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),const char * const * func2_names,double (* const * funcs2)(void *,double,double),void * opaque,int log_offset,void * log_ctx)776 int av_expr_parse_and_eval(double *d, const char *s,
777 const char * const *const_names, const double *const_values,
778 const char * const *func1_names, double (* const *funcs1)(void *, double),
779 const char * const *func2_names, double (* const *funcs2)(void *, double, double),
780 void *opaque, int log_offset, void *log_ctx)
781 {
782 AVExpr *e = NULL;
783 int ret = av_expr_parse(&e, s, const_names, func1_names, funcs1, func2_names, funcs2, log_offset, log_ctx);
784
785 if (ret < 0) {
786 *d = NAN;
787 return ret;
788 }
789 *d = av_expr_eval(e, const_values, opaque);
790 av_expr_free(e);
791 return isnan(*d) ? AVERROR(EINVAL) : 0;
792 }
793