FFmpeg: libavutil/eval.c Source File

FFmpeg

[フレーム]

libavutil

eval.c

Go to the documentation of this file.

1 /*

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 */

22 /**

23 * @file

24 * simple arithmetic expression evaluator.

25 *

26 * see http://joe.hotchkiss.com/programming/eval/eval.html

27 */

29 #include <float.h>

30 #include "attributes.h"

31 #include "avutil.h"

32 #include "common.h"

33 #include "eval.h"

34 #include "log.h"

35 #include "mathematics.h"

36 #include "time.h"

37 #include "avstring.h"

39 typedef struct Parser {

40 const AVClass *class;

41 int stack_index;

42 char *s;

43 const double *const_values;

44 const char * const *const_names; // NULL terminated

45 double (* const *funcs1)(void *, double a); // NULL terminated

46 const char * const *func1_names; // NULL terminated

47 double (* const *funcs2)(void *, double a, double b); // NULL terminated

48 const char * const *func2_names; // NULL terminated

49 void *opaque;

50 int log_offset;

51 void *log_ctx;

52 #define VARS 10

53 double *var;

54 } Parser;

56 static const AVClass eval_class = { "Eval", av_default_item_name, NULL, LIBAVUTIL_VERSION_INT, offsetof(Parser,log_offset), offsetof(Parser,log_ctx) };

58 static const int8_t si_prefixes['z' - 'E' + 1] = {

59 ['y'-'E']= -24,

60 ['z'-'E']= -21,

61 ['a'-'E']= -18,

62 ['f'-'E']= -15,

63 ['p'-'E']= -12,

64 ['n'-'E']= - 9,

65 ['u'-'E']= - 6,

66 ['m'-'E']= - 3,

67 ['c'-'E']= - 2,

68 ['d'-'E']= - 1,

69 ['h'-'E']= 2,

70 ['k'-'E']= 3,

71 ['K'-'E']= 3,

72 ['M'-'E']= 6,

73 ['G'-'E']= 9,

74 ['T'-'E']= 12,

75 ['P'-'E']= 15,

76 ['E'-'E']= 18,

77 ['Z'-'E']= 21,

78 ['Y'-'E']= 24,

79 };

81 static const struct {

82 const char *name;

83 double value;

84 } constants[] = {

85 { "E", M_E },

86 { "PI", M_PI },

87 { "PHI", M_PHI },

88 };

90 double av_strtod(const char *numstr, char **tail)

91 {

92 double d;

93 char *next;

94 if(numstr[0]=='0' && (numstr[1]|0x20)=='x') {

95 d = strtoul(numstr, &next, 16);

96 } else

97 d = strtod(numstr, &next);

98 /* if parsing succeeded, check for and interpret postfixes */

99 if (next!=numstr) {

100 if (next[0] == 'd' && next[1] == 'B') {

101 /* treat dB as decibels instead of decibytes */

102 d = pow(10, d / 20);

103 next += 2;

104 } else if (*next >= 'E' && *next <= 'z') {

105 int e= si_prefixes[*next - 'E'];

106 if (e) {

107 if (next[1] == 'i') {

108 d*= pow( 2, e/0.3);

109 next+=2;

110 } else {

111 d*= pow(10, e);

112 next++;

113 }

114 }

115 }

116

117 if (*next=='B') {

118 d*=8;

119 next++;

120 }

121 }

122 /* if requested, fill in tail with the position after the last parsed

123 character */

124 if (tail)

125 *tail = next;

126 return d;

127 }

128

129 #define IS_IDENTIFIER_CHAR(c) ((c) - '0' <= 9U || (c) - 'a' <= 25U || (c) - 'A' <= 25U || (c) == '_')

130

131 static int strmatch(const char *s, const char *prefix)

132 {

133 int i;

134 for (i=0; prefix[i]; i++) {

135 if (prefix[i] != s[i]) return 0;

136 }

137 /* return 1 only if the s identifier is terminated */

138 return !IS_IDENTIFIER_CHAR(s[i]);

139 }

140

141 struct AVExpr {

142 enum {

143 e_value, e_const, e_func0, e_func1, e_func2,

144 e_squish, e_gauss, e_ld, e_isnan, e_isinf,

145 e_mod, e_max, e_min, e_eq, e_gt, e_gte, e_lte, e_lt,

146 e_pow, e_mul, e_div, e_add,

147 e_last, e_st, e_while, e_taylor, e_root, e_floor, e_ceil, e_trunc,

148 e_sqrt, e_not, e_random, e_hypot, e_gcd,

149 e_if, e_ifnot, e_print, e_bitand, e_bitor, e_between,

150 } type;

151 double value; // is sign in other types

152 union {

153 int const_index;

154 double (*func0)(double);

155 double (*func1)(void *, double);

156 double (*func2)(void *, double, double);

157 } a;

158 struct AVExpr *param[3];

159 double *var;

160 };

161

162 static double etime(double v)

163 {

164 return av_gettime() * 0.000001;

165 }

166

167 static double eval_expr(Parser *p, AVExpr *e)

168 {

169 switch (e->type) {

170 case e_value: return e->value;

171 case e_const: return e->value * p->const_values[e->a.const_index];

172 case e_func0: return e->value * e->a.func0(eval_expr(p, e->param[0]));

173 case e_func1: return e->value * e->a.func1(p->opaque, eval_expr(p, e->param[0]));

174 case e_func2: return e->value * e->a.func2(p->opaque, eval_expr(p, e->param[0]), eval_expr(p, e->param[1]));

175 case e_squish: return 1/(1+exp(4*eval_expr(p, e->param[0])));

176 case e_gauss: { double d = eval_expr(p, e->param[0]); return exp(-d*d/2)/sqrt(2*M_PI); }

177 case e_ld: return e->value * p->var[av_clip(eval_expr(p, e->param[0]), 0, VARS-1)];

178 case e_isnan: return e->value * !!isnan(eval_expr(p, e->param[0]));

179 case e_isinf: return e->value * !!isinf(eval_expr(p, e->param[0]));

180 case e_floor: return e->value * floor(eval_expr(p, e->param[0]));

181 case e_ceil : return e->value * ceil (eval_expr(p, e->param[0]));

182 case e_trunc: return e->value * trunc(eval_expr(p, e->param[0]));

183 case e_sqrt: return e->value * sqrt (eval_expr(p, e->param[0]));

184 case e_not: return e->value * (eval_expr(p, e->param[0]) == 0);

185 case e_if: return e->value * (eval_expr(p, e->param[0]) ? eval_expr(p, e->param[1]) :

186 e->param[2] ? eval_expr(p, e->param[2]) : 0);

187 case e_ifnot: return e->value * (!eval_expr(p, e->param[0]) ? eval_expr(p, e->param[1]) :

188 e->param[2] ? eval_expr(p, e->param[2]) : 0);

189 case e_between: {

190 double d = eval_expr(p, e->param[0]);

191 return e->value * (d >= eval_expr(p, e->param[1]) &&

192 d <= eval_expr(p, e->param[2]));

193 }

194 case e_print: {

195 double x = eval_expr(p, e->param[0]);

196 int level = e->param[1] ? av_clip(eval_expr(p, e->param[1]), INT_MIN, INT_MAX) : AV_LOG_INFO;

197 av_log(p, level, "%f\n", x);

198 return x;

199 }

200 case e_random:{

201 int idx= av_clip(eval_expr(p, e->param[0]), 0, VARS-1);

202 uint64_t r= isnan(p->var[idx]) ? 0 : p->var[idx];

203 r= r*1664525+1013904223;

204 p->var[idx]= r;

205 return e->value * (r * (1.0/UINT64_MAX));

206 }

207 case e_while: {

208 double d = NAN;

209 while (eval_expr(p, e->param[0]))

210 d=eval_expr(p, e->param[1]);

211 return d;

212 }

213 case e_taylor: {

214 double t = 1, d = 0, v;

215 double x = eval_expr(p, e->param[1]);

216 int id = e->param[2] ? av_clip(eval_expr(p, e->param[2]), 0, VARS-1) : 0;

217 int i;

218 double var0 = p->var[id];

219 for(i=0; i<1000; i++) {

220 double ld = d;

221 p->var[id] = i;

222 v = eval_expr(p, e->param[0]);

223 d += t*v;

224 if(ld==d && v)

225 break;

226 t *= x / (i+1);

227 }

228 p->var[id] = var0;

229 return d;

230 }

231 case e_root: {

232 int i, j;

233 double low = -1, high = -1, v, low_v = -DBL_MAX, high_v = DBL_MAX;

234 double var0 = p->var[0];

235 double x_max = eval_expr(p, e->param[1]);

236 for(i=-1; i<1024; i++) {

237 if(i<255) {

238 p->var[0] = av_reverse[i&255]*x_max/255;

239 } else {

240 p->var[0] = x_max*pow(0.9, i-255);

241 if (i&1) p->var[0] *= -1;

242 if (i&2) p->var[0] += low;

243 else p->var[0] += high;

244 }

245 v = eval_expr(p, e->param[0]);

246 if (v<=0 && v>low_v) {

247 low = p->var[0];

248 low_v = v;

249 }

250 if (v>=0 && v<high_v) {

251 high = p->var[0];

252 high_v = v;

253 }

254 if (low>=0 && high>=0){

255 for (j=0; j<1000; j++) {

256 p->var[0] = (low+high)*0.5;

257 if (low == p->var[0] || high == p->var[0])

258 break;

259 v = eval_expr(p, e->param[0]);

260 if (v<=0) low = p->var[0];

261 if (v>=0) high= p->var[0];

262 if (isnan(v)) {

263 low = high = v;

264 break;

265 }

266 }

267 break;

268 }

269 }

270 p->var[0] = var0;

271 return -low_v<high_v ? low : high;

272 }

273 default: {

274 double d = eval_expr(p, e->param[0]);

275 double d2 = eval_expr(p, e->param[1]);

276 switch (e->type) {

277 case e_mod: return e->value * (d - floor((!CONFIG_FTRAPV || d2) ? d / d2 : d * INFINITY) * d2);

278 case e_gcd: return e->value * av_gcd(d,d2);

279 case e_max: return e->value * (d > d2 ? d : d2);

280 case e_min: return e->value * (d < d2 ? d : d2);

281 case e_eq: return e->value * (d == d2 ? 1.0 : 0.0);

282 case e_gt: return e->value * (d > d2 ? 1.0 : 0.0);

283 case e_gte: return e->value * (d >= d2 ? 1.0 : 0.0);

284 case e_lt: return e->value * (d < d2 ? 1.0 : 0.0);

285 case e_lte: return e->value * (d <= d2 ? 1.0 : 0.0);

286 case e_pow: return e->value * pow(d, d2);

287 case e_mul: return e->value * (d * d2);

288 case e_div: return e->value * ((!CONFIG_FTRAPV || d2 ) ? (d / d2) : d * INFINITY);

289 case e_add: return e->value * (d + d2);

290 case e_last:return e->value * d2;

291 case e_st : return e->value * (p->var[av_clip(d, 0, VARS-1)]= d2);

292 case e_hypot:return e->value * (sqrt(d*d + d2*d2));

293 case e_bitand: return isnan(d) || isnan(d2) ? NAN : e->value * ((long int)d & (long int)d2);

294 case e_bitor: return isnan(d) || isnan(d2) ? NAN : e->value * ((long int)d | (long int)d2);

295 }

296 }

297 }

298 return NAN;

299 }

300

301 static int parse_expr(AVExpr **e, Parser *p);

302

303 void av_expr_free(AVExpr *e)

304 {

305 if (!e) return;

306 av_expr_free(e->param[0]);

307 av_expr_free(e->param[1]);

308 av_expr_free(e->param[2]);

309 av_freep(&e->var);

310 av_freep(&e);

311 }

312

313 static int parse_primary(AVExpr **e, Parser *p)

314 {

315 AVExpr *d = av_mallocz(sizeof(AVExpr));

316 char *next = p->s, *s0 = p->s;

317 int ret, i;

318

319 if (!d)

320 return AVERROR(ENOMEM);

321

322 /* number */

323 d->value = av_strtod(p->s, &next);

324 if (next != p->s) {

325 d->type = e_value;

326 p->s= next;

327 *e = d;

328 return 0;

329 }

330 d->value = 1;

331

332 /* named constants */

333 for (i=0; p->const_names && p->const_names[i]; i++) {

334 if (strmatch(p->s, p->const_names[i])) {

335 p->s+= strlen(p->const_names[i]);

336 d->type = e_const;

337 d->a.const_index = i;

338 *e = d;

339 return 0;

340 }

341 }

342 for (i = 0; i < FF_ARRAY_ELEMS(constants); i++) {

343 if (strmatch(p->s, constants[i].name)) {

344 p->s += strlen(constants[i].name);

345 d->type = e_value;

346 d->value = constants[i].value;

347 *e = d;

348 return 0;

349 }

350 }

351

352 p->s= strchr(p->s, '(');

353 if (p->s==NULL) {

354 av_log(p, AV_LOG_ERROR, "Undefined constant or missing '(' in '%s'\n", s0);

355 p->s= next;

356 av_expr_free(d);

357 return AVERROR(EINVAL);

358 }

359 p->s++; // "("

360 if (*next == '(') { // special case do-nothing

361 av_freep(&d);

362 if ((ret = parse_expr(&d, p)) < 0)

363 return ret;

364 if (p->s[0] != ')') {

365 av_log(p, AV_LOG_ERROR, "Missing ')' in '%s'\n", s0);

366 av_expr_free(d);

367 return AVERROR(EINVAL);

368 }

369 p->s++; // ")"

370 *e = d;

371 return 0;

372 }

373 if ((ret = parse_expr(&(d->param[0]), p)) < 0) {

374 av_expr_free(d);

375 return ret;

376 }

377 if (p->s[0]== ',') {

378 p->s++; // ","

379 parse_expr(&d->param[1], p);

380 }

381 if (p->s[0]== ',') {

382 p->s++; // ","

383 parse_expr(&d->param[2], p);

384 }

385 if (p->s[0] != ')') {

386 av_log(p, AV_LOG_ERROR, "Missing ')' or too many args in '%s'\n", s0);

387 av_expr_free(d);

388 return AVERROR(EINVAL);

389 }

390 p->s++; // ")"

391

392 d->type = e_func0;

393 if (strmatch(next, "sinh" )) d->a.func0 = sinh;

394 else if (strmatch(next, "cosh" )) d->a.func0 = cosh;

395 else if (strmatch(next, "tanh" )) d->a.func0 = tanh;

396 else if (strmatch(next, "sin" )) d->a.func0 = sin;

397 else if (strmatch(next, "cos" )) d->a.func0 = cos;

398 else if (strmatch(next, "tan" )) d->a.func0 = tan;

399 else if (strmatch(next, "atan" )) d->a.func0 = atan;

400 else if (strmatch(next, "asin" )) d->a.func0 = asin;

401 else if (strmatch(next, "acos" )) d->a.func0 = acos;

402 else if (strmatch(next, "exp" )) d->a.func0 = exp;

403 else if (strmatch(next, "log" )) d->a.func0 = log;

404 else if (strmatch(next, "abs" )) d->a.func0 = fabs;

405 else if (strmatch(next, "time" )) d->a.func0 = etime;

406 else if (strmatch(next, "squish")) d->type = e_squish;

407 else if (strmatch(next, "gauss" )) d->type = e_gauss;

408 else if (strmatch(next, "mod" )) d->type = e_mod;

409 else if (strmatch(next, "max" )) d->type = e_max;

410 else if (strmatch(next, "min" )) d->type = e_min;

411 else if (strmatch(next, "eq" )) d->type = e_eq;

412 else if (strmatch(next, "gte" )) d->type = e_gte;

413 else if (strmatch(next, "gt" )) d->type = e_gt;

414 else if (strmatch(next, "lte" )) d->type = e_lte;

415 else if (strmatch(next, "lt" )) d->type = e_lt;

416 else if (strmatch(next, "ld" )) d->type = e_ld;

417 else if (strmatch(next, "isnan" )) d->type = e_isnan;

418 else if (strmatch(next, "isinf" )) d->type = e_isinf;

419 else if (strmatch(next, "st" )) d->type = e_st;

420 else if (strmatch(next, "while" )) d->type = e_while;

421 else if (strmatch(next, "taylor")) d->type = e_taylor;

422 else if (strmatch(next, "root" )) d->type = e_root;

423 else if (strmatch(next, "floor" )) d->type = e_floor;

424 else if (strmatch(next, "ceil" )) d->type = e_ceil;

425 else if (strmatch(next, "trunc" )) d->type = e_trunc;

426 else if (strmatch(next, "sqrt" )) d->type = e_sqrt;

427 else if (strmatch(next, "not" )) d->type = e_not;

428 else if (strmatch(next, "pow" )) d->type = e_pow;

429 else if (strmatch(next, "print" )) d->type = e_print;

430 else if (strmatch(next, "random")) d->type = e_random;

431 else if (strmatch(next, "hypot" )) d->type = e_hypot;

432 else if (strmatch(next, "gcd" )) d->type = e_gcd;

433 else if (strmatch(next, "if" )) d->type = e_if;

434 else if (strmatch(next, "ifnot" )) d->type = e_ifnot;

435 else if (strmatch(next, "bitand")) d->type = e_bitand;

436 else if (strmatch(next, "bitor" )) d->type = e_bitor;

437 else if (strmatch(next, "between"))d->type = e_between;

438 else {

439 for (i=0; p->func1_names && p->func1_names[i]; i++) {

440 if (strmatch(next, p->func1_names[i])) {

441 d->a.func1 = p->funcs1[i];

442 d->type = e_func1;

443 *e = d;

444 return 0;

445 }

446 }

447

448 for (i=0; p->func2_names && p->func2_names[i]; i++) {

449 if (strmatch(next, p->func2_names[i])) {

450 d->a.func2 = p->funcs2[i];

451 d->type = e_func2;

452 *e = d;

453 return 0;

454 }

455 }

456

457 av_log(p, AV_LOG_ERROR, "Unknown function in '%s'\n", s0);

458 av_expr_free(d);

459 return AVERROR(EINVAL);

460 }

461

462 *e = d;

463 return 0;

464 }

465

466 static AVExpr *make_eval_expr(int type, int value, AVExpr *p0, AVExpr *p1)

467 {

468 AVExpr *e = av_mallocz(sizeof(AVExpr));

469 if (!e)

470 return NULL;

471 e->type =type ;

472 e->value =value ;

473 e->param[0] =p0 ;

474 e->param[1] =p1 ;

475 return e;

476 }

477

478 static int parse_pow(AVExpr **e, Parser *p, int *sign)

479 {

480 *sign= (*p->s == '+') - (*p->s == '-');

481 p->s += *sign&1;

482 return parse_primary(e, p);

483 }

484

485 static int parse_dB(AVExpr **e, Parser *p, int *sign)

486 {

487 /* do not filter out the negative sign when parsing a dB value.

488 for example, -3dB is not the same as -(3dB) */

489 if (*p->s == '-') {

490 char *next;

491 double av_unused ignored = strtod(p->s, &next);

492 if (next != p->s && next[0] == 'd' && next[1] == 'B') {

493 *sign = 0;

494 return parse_primary(e, p);

495 }

496 }

497 return parse_pow(e, p, sign);

498 }

499

500 static int parse_factor(AVExpr **e, Parser *p)

501 {

502 int sign, sign2, ret;

503 AVExpr *e0, *e1, *e2;

504 if ((ret = parse_dB(&e0, p, &sign)) < 0)

505 return ret;

506 while(p->s[0]=='^'){

507 e1 = e0;

508 p->s++;

509 if ((ret = parse_dB(&e2, p, &sign2)) < 0) {

510 av_expr_free(e1);

511 return ret;

512 }

513 e0 = make_eval_expr(e_pow, 1, e1, e2);

514 if (!e0) {

515 av_expr_free(e1);

516 av_expr_free(e2);

517 return AVERROR(ENOMEM);

518 }

519 if (e0->param[1]) e0->param[1]->value *= (sign2|1);

520 }

521 if (e0) e0->value *= (sign|1);

522

523 *e = e0;

524 return 0;

525 }

526

527 static int parse_term(AVExpr **e, Parser *p)

528 {

529 int ret;

530 AVExpr *e0, *e1, *e2;

531 if ((ret = parse_factor(&e0, p)) < 0)

532 return ret;

533 while (p->s[0]=='*' || p->s[0]=='/') {

534 int c= *p->s++;

535 e1 = e0;

536 if ((ret = parse_factor(&e2, p)) < 0) {

537 av_expr_free(e1);

538 return ret;

539 }

540 e0 = make_eval_expr(c == '*' ? e_mul : e_div, 1, e1, e2);

541 if (!e0) {

542 av_expr_free(e1);

543 av_expr_free(e2);

544 return AVERROR(ENOMEM);

545 }

546 }

547 *e = e0;

548 return 0;

549 }

550

551 static int parse_subexpr(AVExpr **e, Parser *p)

552 {

553 int ret;

554 AVExpr *e0, *e1, *e2;

555 if ((ret = parse_term(&e0, p)) < 0)

556 return ret;

557 while (*p->s == '+' || *p->s == '-') {

558 e1 = e0;

559 if ((ret = parse_term(&e2, p)) < 0) {

560 av_expr_free(e1);

561 return ret;

562 }

563 e0 = make_eval_expr(e_add, 1, e1, e2);

564 if (!e0) {

565 av_expr_free(e1);

566 av_expr_free(e2);

567 return AVERROR(ENOMEM);

568 }

569 };

570

571 *e = e0;

572 return 0;

573 }

574

575 static int parse_expr(AVExpr **e, Parser *p)

576 {

577 int ret;

578 AVExpr *e0, *e1, *e2;

579 if (p->stack_index <= 0) //protect against stack overflows

580 return AVERROR(EINVAL);

581 p->stack_index--;

582

583 if ((ret = parse_subexpr(&e0, p)) < 0)

584 return ret;

585 while (*p->s == ';') {

586 p->s++;

587 e1 = e0;

588 if ((ret = parse_subexpr(&e2, p)) < 0) {

589 av_expr_free(e1);

590 return ret;

591 }

592 e0 = make_eval_expr(e_last, 1, e1, e2);

593 if (!e0) {

594 av_expr_free(e1);

595 av_expr_free(e2);

596 return AVERROR(ENOMEM);

597 }

598 };

599

600 p->stack_index++;

601 *e = e0;

602 return 0;

603 }

604

605 static int verify_expr(AVExpr *e)

606 {

607 if (!e) return 0;

608 switch (e->type) {

609 case e_value:

610 case e_const: return 1;

611 case e_func0:

612 case e_func1:

613 case e_squish:

614 case e_ld:

615 case e_gauss:

616 case e_isnan:

617 case e_isinf:

618 case e_floor:

619 case e_ceil:

620 case e_trunc:

621 case e_sqrt:

622 case e_not:

623 case e_random:

624 return verify_expr(e->param[0]) && !e->param[1];

625 case e_print:

626 return verify_expr(e->param[0])

627 && (!e->param[1] || verify_expr(e->param[1]));

628 case e_if:

629 case e_ifnot:

630 case e_taylor:

631 return verify_expr(e->param[0]) && verify_expr(e->param[1])

632 && (!e->param[2] || verify_expr(e->param[2]));

633 case e_between:

634 return verify_expr(e->param[0]) &&

635 verify_expr(e->param[1]) &&

636 verify_expr(e->param[2]);

637 default: return verify_expr(e->param[0]) && verify_expr(e->param[1]) && !e->param[2];

638 }

639 }

640

641 int av_expr_parse(AVExpr **expr, const char *s,

642 const char * const *const_names,

643 const char * const *func1_names, double (* const *funcs1)(void *, double),

644 const char * const *func2_names, double (* const *funcs2)(void *, double, double),

645 int log_offset, void *log_ctx)

646 {

647 Parser p = { 0 };

648 AVExpr *e = NULL;

649 char *w = av_malloc(strlen(s) + 1);

650 char *wp = w;

651 const char *s0 = s;

652 int ret = 0;

653

654 if (!w)

655 return AVERROR(ENOMEM);

656

657 while (*s)

658 if (!av_isspace(*s++)) *wp++ = s[-1];

659 *wp++ = 0;

660

661 p.class = &eval_class;

662 p.stack_index=100;

663 p.s= w;

664 p.const_names = const_names;

665 p.funcs1 = funcs1;

666 p.func1_names = func1_names;

667 p.funcs2 = funcs2;

668 p.func2_names = func2_names;

669 p.log_offset = log_offset;

670 p.log_ctx = log_ctx;

671

672 if ((ret = parse_expr(&e, &p)) < 0)

673 goto end;

674 if (*p.s) {

675 av_expr_free(e);

676 av_log(&p, AV_LOG_ERROR, "Invalid chars '%s' at the end of expression '%s'\n", p.s, s0);

677 ret = AVERROR(EINVAL);

678 goto end;

679 }

680 if (!verify_expr(e)) {

681 av_expr_free(e);

682 ret = AVERROR(EINVAL);

683 goto end;

684 }

685 e->var= av_mallocz(sizeof(double) *VARS);

686 *expr = e;

687 end:

688 av_free(w);

689 return ret;

690 }

691

692 double av_expr_eval(AVExpr *e, const double *const_values, void *opaque)

693 {

694 Parser p = { 0 };

695 p.var= e->var;

696

697 p.const_values = const_values;

698 p.opaque = opaque;

699 return eval_expr(&p, e);

700 }

701

702 int av_expr_parse_and_eval(double *d, const char *s,

703 const char * const *const_names, const double *const_values,

704 const char * const *func1_names, double (* const *funcs1)(void *, double),

705 const char * const *func2_names, double (* const *funcs2)(void *, double, double),

706 void *opaque, int log_offset, void *log_ctx)

707 {

708 AVExpr *e = NULL;

709 int ret = av_expr_parse(&e, s, const_names, func1_names, funcs1, func2_names, funcs2, log_offset, log_ctx);

710

711 if (ret < 0) {

712 *d = NAN;

713 return ret;

714 }

715 *d = av_expr_eval(e, const_values, opaque);

716 av_expr_free(e);

717 return isnan(*d) ? AVERROR(EINVAL) : 0;

718 }

719

720 #ifdef TEST

721 #include <string.h>

722

723 static const double const_values[] = {

724 M_PI,

725 M_E,

726 0

727 };

728

729 static const char *const const_names[] = {

730 "PI",

731 "E",

732 0

733 };

734

735 int main(int argc, char **argv)

736 {

737 int i;

738 double d;

739 const char *const *expr;

740 static const char *const exprs[] = {

741 "",

742 "1;2",

743 "-20",

744 "-PI",

745 "+PI",

746 "1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)",

747 "80G/80Gi",

748 "1k",

749 "1Gi",

750 "1gi",

751 "1GiFoo",

752 "1k+1k",

753 "1Gi*3foo",

754 "foo",

755 "foo(",

756 "foo()",

757 "foo)",

758 "sin",

759 "sin(",

760 "sin()",

761 "sin)",

762 "sin 10",

763 "sin(1,2,3)",

764 "sin(1 )",

765 "1",

766 "1foo",

767 "bar + PI + E + 100f*2 + foo",

768 "13k + 12f - foo(1, 2)",

769 "1gi",

770 "1Gi",

771 "st(0, 123)",

772 "st(1, 123); ld(1)",

773 "lte(0, 1)",

774 "lte(1, 1)",

775 "lte(1, 0)",

776 "lt(0, 1)",

777 "lt(1, 1)",

778 "gt(1, 0)",

779 "gt(2, 7)",

780 "gte(122, 122)",

781 /* compute 1+2+...+N */

782 "st(0, 1); while(lte(ld(0), 100), st(1, ld(1)+ld(0));st(0, ld(0)+1)); ld(1)",

783 /* compute Fib(N) */

784 "st(1, 1); st(2, 2); st(0, 1); while(lte(ld(0),10), st(3, ld(1)+ld(2)); st(1, ld(2)); st(2, ld(3)); st(0, ld(0)+1)); ld(3)",

785 "while(0, 10)",

786 "st(0, 1); while(lte(ld(0),100), st(1, ld(1)+ld(0)); st(0, ld(0)+1))",

787 "isnan(1)",

788 "isnan(NAN)",

789 "isnan(INF)",

790 "isinf(1)",

791 "isinf(NAN)",

792 "isinf(INF)",

793 "floor(NAN)",

794 "floor(123.123)",

795 "floor(-123.123)",

796 "trunc(123.123)",

797 "trunc(-123.123)",

798 "ceil(123.123)",

799 "ceil(-123.123)",

800 "sqrt(1764)",

801 "isnan(sqrt(-1))",

802 "not(1)",

803 "not(NAN)",

804 "not(0)",

805 "6.0206dB",

806 "-3.0103dB",

807 "pow(0,1.23)",

808 "pow(PI,1.23)",

809 "PI^1.23",

810 "pow(-1,1.23)",

811 "if(1, 2)",

812 "if(1, 1, 2)",

813 "if(0, 1, 2)",

814 "ifnot(0, 23)",

815 "ifnot(1, NaN) + if(0, 1)",

816 "ifnot(1, 1, 2)",

817 "ifnot(0, 1, 2)",

818 "taylor(1, 1)",

819 "taylor(eq(mod(ld(1),4),1)-eq(mod(ld(1),4),3), PI/2, 1)",

820 "root(sin(ld(0))-1, 2)",

821 "root(sin(ld(0))+6+sin(ld(0)/12)-log(ld(0)), 100)",

822 "7000000B*random(0)",

823 "squish(2)",

824 "gauss(0.1)",

825 "hypot(4,3)",

826 "gcd(30,55)*print(min(9,1))",

827 "bitor(42, 12)",

828 "bitand(42, 12)",

829 "bitand(NAN, 1)",

830 "between(10, -3, 10)",

831 "between(-4, -2, -1)",

832 "between(1,2)",

833 NULL

834 };

835

836 for (expr = exprs; *expr; expr++) {

837 printf("Evaluating '%s'\n", *expr);

838 av_expr_parse_and_eval(&d, *expr,

839 const_names, const_values,

840 NULL, NULL, NULL, NULL, NULL, 0, NULL);

841 if (isnan(d))

842 printf("'%s' -> nan\n\n", *expr);

843 else

844 printf("'%s' -> %f\n\n", *expr, d);

845 }

846

847 av_expr_parse_and_eval(&d, "1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)",

848 const_names, const_values,

849 NULL, NULL, NULL, NULL, NULL, 0, NULL);

850 printf("%f == 12.7\n", d);

851 av_expr_parse_and_eval(&d, "80G/80Gi",

852 const_names, const_values,

853 NULL, NULL, NULL, NULL, NULL, 0, NULL);

854 printf("%f == 0.931322575\n", d);

855

856 if (argc > 1 && !strcmp(argv[1], "-t")) {

857 for (i = 0; i < 1050; i++) {

858 START_TIMER;

859 av_expr_parse_and_eval(&d, "1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)",

860 const_names, const_values,

861 NULL, NULL, NULL, NULL, NULL, 0, NULL);

862 STOP_TIMER("av_expr_parse_and_eval");

863 }

864 }

865

866 return 0;

867 }

868 #endif

Generated on Sat Jan 25 2014 19:52:06 for FFmpeg by doxygen 1.8.2