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 43typedef 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 60static 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 69static 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 96static 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 106double 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 147static 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 157struct 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 179static double etime(double v) 180{ 181 return av_gettime() * 0.000001; 182} 183 184static 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 334static int parse_expr(AVExpr **e, Parser *p); 335 336void 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 346static 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 506static 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 518static 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 525static 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 540static 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 567static 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 591static 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 615static 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 645static 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 685int 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; 734end: 735 av_expr_free(e); 736 av_free(w); 737 return ret; 738} 739 740static 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 756int av_expr_count_vars(AVExpr *e, unsigned *counter, int size) 757{ 758 return expr_count(e, counter, size, e_const); 759} 760 761int 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 766double 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 776int 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