eval.c
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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 Libav.
6  *
7  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
29 #include "avutil.h"
30 #include "common.h"
31 #include "eval.h"
32 #include "log.h"
33 #include "mathematics.h"
34 
35 typedef struct Parser {
36  const AVClass *class;
38  char *s;
39  const double *const_values;
40  const char * const *const_names; // NULL terminated
41  double (* const *funcs1)(void *, double a); // NULL terminated
42  const char * const *func1_names; // NULL terminated
43  double (* const *funcs2)(void *, double a, double b); // NULL terminated
44  const char * const *func2_names; // NULL terminated
45  void *opaque;
47  void *log_ctx;
48 #define VARS 10
49  double var[VARS];
50 } Parser;
51 
52 static const AVClass class = { "Eval", av_default_item_name, NULL, LIBAVUTIL_VERSION_INT, offsetof(Parser,log_offset), offsetof(Parser,log_ctx) };
53 
54 static const int8_t si_prefixes['z' - 'E' + 1] = {
55  ['y'-'E']= -24,
56  ['z'-'E']= -21,
57  ['a'-'E']= -18,
58  ['f'-'E']= -15,
59  ['p'-'E']= -12,
60  ['n'-'E']= - 9,
61  ['u'-'E']= - 6,
62  ['m'-'E']= - 3,
63  ['c'-'E']= - 2,
64  ['d'-'E']= - 1,
65  ['h'-'E']= 2,
66  ['k'-'E']= 3,
67  ['K'-'E']= 3,
68  ['M'-'E']= 6,
69  ['G'-'E']= 9,
70  ['T'-'E']= 12,
71  ['P'-'E']= 15,
72  ['E'-'E']= 18,
73  ['Z'-'E']= 21,
74  ['Y'-'E']= 24,
75 };
76 
77 double av_strtod(const char *numstr, char **tail)
78 {
79  double d;
80  char *next;
81  d = strtod(numstr, &next);
82  /* if parsing succeeded, check for and interpret postfixes */
83  if (next!=numstr) {
84  if (next[0] == 'd' && next[1] == 'B') {
85  /* treat dB as decibels instead of decibytes */
86  d = pow(10, d / 20);
87  next += 2;
88  } else if (*next >= 'E' && *next <= 'z') {
89  int e= si_prefixes[*next - 'E'];
90  if (e) {
91  if (next[1] == 'i') {
92  d*= pow( 2, e/0.3);
93  next+=2;
94  } else {
95  d*= pow(10, e);
96  next++;
97  }
98  }
99  }
100 
101  if (*next=='B') {
102  d*=8;
103  next++;
104  }
105  }
106  /* if requested, fill in tail with the position after the last parsed
107  character */
108  if (tail)
109  *tail = next;
110  return d;
111 }
112 
113 #define IS_IDENTIFIER_CHAR(c) ((c) - '0' <= 9U || (c) - 'a' <= 25U || (c) - 'A' <= 25U || (c) == '_')
114 
115 static int strmatch(const char *s, const char *prefix)
116 {
117  int i;
118  for (i=0; prefix[i]; i++) {
119  if (prefix[i] != s[i]) return 0;
120  }
121  /* return 1 only if the s identifier is terminated */
122  return !IS_IDENTIFIER_CHAR(s[i]);
123 }
124 
125 struct AVExpr {
126  enum {
133  } type;
134  double value; // is sign in other types
135  union {
137  double (*func0)(double);
138  double (*func1)(void *, double);
139  double (*func2)(void *, double, double);
140  } a;
141  struct AVExpr *param[2];
142 };
143 
144 static double eval_expr(Parser *p, AVExpr *e)
145 {
146  switch (e->type) {
147  case e_value: return e->value;
148  case e_const: return e->value * p->const_values[e->a.const_index];
149  case e_func0: return e->value * e->a.func0(eval_expr(p, e->param[0]));
150  case e_func1: return e->value * e->a.func1(p->opaque, eval_expr(p, e->param[0]));
151  case e_func2: return e->value * e->a.func2(p->opaque, eval_expr(p, e->param[0]), eval_expr(p, e->param[1]));
152  case e_squish: return 1/(1+exp(4*eval_expr(p, e->param[0])));
153  case e_gauss: { double d = eval_expr(p, e->param[0]); return exp(-d*d/2)/sqrt(2*M_PI); }
154  case e_ld: return e->value * p->var[av_clip(eval_expr(p, e->param[0]), 0, VARS-1)];
155  case e_isnan: return e->value * !!isnan(eval_expr(p, e->param[0]));
156  case e_isinf: return e->value * !!isinf(eval_expr(p, e->param[0]));
157  case e_floor: return e->value * floor(eval_expr(p, e->param[0]));
158  case e_ceil : return e->value * ceil (eval_expr(p, e->param[0]));
159  case e_trunc: return e->value * trunc(eval_expr(p, e->param[0]));
160  case e_sqrt: return e->value * sqrt (eval_expr(p, e->param[0]));
161  case e_not: return e->value * eval_expr(p, e->param[0]) == 0;
162  case e_while: {
163  double d = NAN;
164  while (eval_expr(p, e->param[0]))
165  d=eval_expr(p, e->param[1]);
166  return d;
167  }
168  default: {
169  double d = eval_expr(p, e->param[0]);
170  double d2 = eval_expr(p, e->param[1]);
171  switch (e->type) {
172  case e_mod: return e->value * (d - floor(d/d2)*d2);
173  case e_max: return e->value * (d > d2 ? d : d2);
174  case e_min: return e->value * (d < d2 ? d : d2);
175  case e_eq: return e->value * (d == d2 ? 1.0 : 0.0);
176  case e_gt: return e->value * (d > d2 ? 1.0 : 0.0);
177  case e_gte: return e->value * (d >= d2 ? 1.0 : 0.0);
178  case e_pow: return e->value * pow(d, d2);
179  case e_mul: return e->value * (d * d2);
180  case e_div: return e->value * (d / d2);
181  case e_add: return e->value * (d + d2);
182  case e_last:return e->value * d2;
183  case e_st : return e->value * (p->var[av_clip(d, 0, VARS-1)]= d2);
184  }
185  }
186  }
187  return NAN;
188 }
189 
190 static int parse_expr(AVExpr **e, Parser *p);
191 
193 {
194  if (!e) return;
195  av_expr_free(e->param[0]);
196  av_expr_free(e->param[1]);
197  av_freep(&e);
198 }
199 
200 static int parse_primary(AVExpr **e, Parser *p)
201 {
202  AVExpr *d = av_mallocz(sizeof(AVExpr));
203  char *next = p->s, *s0 = p->s;
204  int ret, i;
205 
206  if (!d)
207  return AVERROR(ENOMEM);
208 
209  /* number */
210  d->value = av_strtod(p->s, &next);
211  if (next != p->s) {
212  d->type = e_value;
213  p->s= next;
214  *e = d;
215  return 0;
216  }
217  d->value = 1;
218 
219  /* named constants */
220  for (i=0; p->const_names && p->const_names[i]; i++) {
221  if (strmatch(p->s, p->const_names[i])) {
222  p->s+= strlen(p->const_names[i]);
223  d->type = e_const;
224  d->a.const_index = i;
225  *e = d;
226  return 0;
227  }
228  }
229 
230  p->s= strchr(p->s, '(');
231  if (p->s==NULL) {
232  av_log(p, AV_LOG_ERROR, "Undefined constant or missing '(' in '%s'\n", s0);
233  p->s= next;
234  av_expr_free(d);
235  return AVERROR(EINVAL);
236  }
237  p->s++; // "("
238  if (*next == '(') { // special case do-nothing
239  av_freep(&d);
240  if ((ret = parse_expr(&d, p)) < 0)
241  return ret;
242  if (p->s[0] != ')') {
243  av_log(p, AV_LOG_ERROR, "Missing ')' in '%s'\n", s0);
244  av_expr_free(d);
245  return AVERROR(EINVAL);
246  }
247  p->s++; // ")"
248  *e = d;
249  return 0;
250  }
251  if ((ret = parse_expr(&(d->param[0]), p)) < 0) {
252  av_expr_free(d);
253  return ret;
254  }
255  if (p->s[0]== ',') {
256  p->s++; // ","
257  parse_expr(&d->param[1], p);
258  }
259  if (p->s[0] != ')') {
260  av_log(p, AV_LOG_ERROR, "Missing ')' or too many args in '%s'\n", s0);
261  av_expr_free(d);
262  return AVERROR(EINVAL);
263  }
264  p->s++; // ")"
265 
266  d->type = e_func0;
267  if (strmatch(next, "sinh" )) d->a.func0 = sinh;
268  else if (strmatch(next, "cosh" )) d->a.func0 = cosh;
269  else if (strmatch(next, "tanh" )) d->a.func0 = tanh;
270  else if (strmatch(next, "sin" )) d->a.func0 = sin;
271  else if (strmatch(next, "cos" )) d->a.func0 = cos;
272  else if (strmatch(next, "tan" )) d->a.func0 = tan;
273  else if (strmatch(next, "atan" )) d->a.func0 = atan;
274  else if (strmatch(next, "asin" )) d->a.func0 = asin;
275  else if (strmatch(next, "acos" )) d->a.func0 = acos;
276  else if (strmatch(next, "exp" )) d->a.func0 = exp;
277  else if (strmatch(next, "log" )) d->a.func0 = log;
278  else if (strmatch(next, "abs" )) d->a.func0 = fabs;
279  else if (strmatch(next, "squish")) d->type = e_squish;
280  else if (strmatch(next, "gauss" )) d->type = e_gauss;
281  else if (strmatch(next, "mod" )) d->type = e_mod;
282  else if (strmatch(next, "max" )) d->type = e_max;
283  else if (strmatch(next, "min" )) d->type = e_min;
284  else if (strmatch(next, "eq" )) d->type = e_eq;
285  else if (strmatch(next, "gte" )) d->type = e_gte;
286  else if (strmatch(next, "gt" )) d->type = e_gt;
287  else if (strmatch(next, "lte" )) { AVExpr *tmp = d->param[1]; d->param[1] = d->param[0]; d->param[0] = tmp; d->type = e_gte; }
288  else if (strmatch(next, "lt" )) { AVExpr *tmp = d->param[1]; d->param[1] = d->param[0]; d->param[0] = tmp; d->type = e_gt; }
289  else if (strmatch(next, "ld" )) d->type = e_ld;
290  else if (strmatch(next, "isnan" )) d->type = e_isnan;
291  else if (strmatch(next, "isinf" )) d->type = e_isinf;
292  else if (strmatch(next, "st" )) d->type = e_st;
293  else if (strmatch(next, "while" )) d->type = e_while;
294  else if (strmatch(next, "floor" )) d->type = e_floor;
295  else if (strmatch(next, "ceil" )) d->type = e_ceil;
296  else if (strmatch(next, "trunc" )) d->type = e_trunc;
297  else if (strmatch(next, "sqrt" )) d->type = e_sqrt;
298  else if (strmatch(next, "not" )) d->type = e_not;
299  else {
300  for (i=0; p->func1_names && p->func1_names[i]; i++) {
301  if (strmatch(next, p->func1_names[i])) {
302  d->a.func1 = p->funcs1[i];
303  d->type = e_func1;
304  *e = d;
305  return 0;
306  }
307  }
308 
309  for (i=0; p->func2_names && p->func2_names[i]; i++) {
310  if (strmatch(next, p->func2_names[i])) {
311  d->a.func2 = p->funcs2[i];
312  d->type = e_func2;
313  *e = d;
314  return 0;
315  }
316  }
317 
318  av_log(p, AV_LOG_ERROR, "Unknown function in '%s'\n", s0);
319  av_expr_free(d);
320  return AVERROR(EINVAL);
321  }
322 
323  *e = d;
324  return 0;
325 }
326 
327 static AVExpr *new_eval_expr(int type, int value, AVExpr *p0, AVExpr *p1)
328 {
329  AVExpr *e = av_mallocz(sizeof(AVExpr));
330  if (!e)
331  return NULL;
332  e->type =type ;
333  e->value =value ;
334  e->param[0] =p0 ;
335  e->param[1] =p1 ;
336  return e;
337 }
338 
339 static int parse_pow(AVExpr **e, Parser *p, int *sign)
340 {
341  *sign= (*p->s == '+') - (*p->s == '-');
342  p->s += *sign&1;
343  return parse_primary(e, p);
344 }
345 
346 static int parse_dB(AVExpr **e, Parser *p, int *sign)
347 {
348  /* do not filter out the negative sign when parsing a dB value.
349  for example, -3dB is not the same as -(3dB) */
350  if (*p->s == '-') {
351  char *next;
352  strtod(p->s, &next);
353  if (next != p->s && next[0] == 'd' && next[1] == 'B') {
354  *sign = 0;
355  return parse_primary(e, p);
356  }
357  }
358  return parse_pow(e, p, sign);
359 }
360 
361 static int parse_factor(AVExpr **e, Parser *p)
362 {
363  int sign, sign2, ret;
364  AVExpr *e0, *e1, *e2;
365  if ((ret = parse_dB(&e0, p, &sign)) < 0)
366  return ret;
367  while(p->s[0]=='^'){
368  e1 = e0;
369  p->s++;
370  if ((ret = parse_dB(&e2, p, &sign2)) < 0) {
371  av_expr_free(e1);
372  return ret;
373  }
374  e0 = new_eval_expr(e_pow, 1, e1, e2);
375  if (!e0) {
376  av_expr_free(e1);
377  av_expr_free(e2);
378  return AVERROR(ENOMEM);
379  }
380  if (e0->param[1]) e0->param[1]->value *= (sign2|1);
381  }
382  if (e0) e0->value *= (sign|1);
383 
384  *e = e0;
385  return 0;
386 }
387 
388 static int parse_term(AVExpr **e, Parser *p)
389 {
390  int ret;
391  AVExpr *e0, *e1, *e2;
392  if ((ret = parse_factor(&e0, p)) < 0)
393  return ret;
394  while (p->s[0]=='*' || p->s[0]=='/') {
395  int c= *p->s++;
396  e1 = e0;
397  if ((ret = parse_factor(&e2, p)) < 0) {
398  av_expr_free(e1);
399  return ret;
400  }
401  e0 = new_eval_expr(c == '*' ? e_mul : e_div, 1, e1, e2);
402  if (!e0) {
403  av_expr_free(e1);
404  av_expr_free(e2);
405  return AVERROR(ENOMEM);
406  }
407  }
408  *e = e0;
409  return 0;
410 }
411 
412 static int parse_subexpr(AVExpr **e, Parser *p)
413 {
414  int ret;
415  AVExpr *e0, *e1, *e2;
416  if ((ret = parse_term(&e0, p)) < 0)
417  return ret;
418  while (*p->s == '+' || *p->s == '-') {
419  e1 = e0;
420  if ((ret = parse_term(&e2, p)) < 0) {
421  av_expr_free(e1);
422  return ret;
423  }
424  e0 = new_eval_expr(e_add, 1, e1, e2);
425  if (!e0) {
426  av_expr_free(e1);
427  av_expr_free(e2);
428  return AVERROR(ENOMEM);
429  }
430  };
431 
432  *e = e0;
433  return 0;
434 }
435 
436 static int parse_expr(AVExpr **e, Parser *p)
437 {
438  int ret;
439  AVExpr *e0, *e1, *e2;
440  if (p->stack_index <= 0) //protect against stack overflows
441  return AVERROR(EINVAL);
442  p->stack_index--;
443 
444  if ((ret = parse_subexpr(&e0, p)) < 0)
445  return ret;
446  while (*p->s == ';') {
447  p->s++;
448  e1 = e0;
449  if ((ret = parse_subexpr(&e2, p)) < 0) {
450  av_expr_free(e1);
451  return ret;
452  }
453  e0 = new_eval_expr(e_last, 1, e1, e2);
454  if (!e0) {
455  av_expr_free(e1);
456  av_expr_free(e2);
457  return AVERROR(ENOMEM);
458  }
459  };
460 
461  p->stack_index++;
462  *e = e0;
463  return 0;
464 }
465 
466 static int verify_expr(AVExpr *e)
467 {
468  if (!e) return 0;
469  switch (e->type) {
470  case e_value:
471  case e_const: return 1;
472  case e_func0:
473  case e_func1:
474  case e_squish:
475  case e_ld:
476  case e_gauss:
477  case e_isnan:
478  case e_isinf:
479  case e_floor:
480  case e_ceil:
481  case e_trunc:
482  case e_sqrt:
483  case e_not:
484  return verify_expr(e->param[0]);
485  default: return verify_expr(e->param[0]) && verify_expr(e->param[1]);
486  }
487 }
488 
489 int av_expr_parse(AVExpr **expr, const char *s,
490  const char * const *const_names,
491  const char * const *func1_names, double (* const *funcs1)(void *, double),
492  const char * const *func2_names, double (* const *funcs2)(void *, double, double),
493  int log_offset, void *log_ctx)
494 {
495  Parser p = { 0 };
496  AVExpr *e = NULL;
497  char *w = av_malloc(strlen(s) + 1);
498  char *wp = w;
499  const char *s0 = s;
500  int ret = 0;
501 
502  if (!w)
503  return AVERROR(ENOMEM);
504 
505  while (*s)
506  if (!isspace(*s++)) *wp++ = s[-1];
507  *wp++ = 0;
508 
509  p.class = &class;
510  p.stack_index=100;
511  p.s= w;
513  p.funcs1 = funcs1;
514  p.func1_names = func1_names;
515  p.funcs2 = funcs2;
516  p.func2_names = func2_names;
517  p.log_offset = log_offset;
518  p.log_ctx = log_ctx;
519 
520  if ((ret = parse_expr(&e, &p)) < 0)
521  goto end;
522  if (*p.s) {
523  av_expr_free(e);
524  av_log(&p, AV_LOG_ERROR, "Invalid chars '%s' at the end of expression '%s'\n", p.s, s0);
525  ret = AVERROR(EINVAL);
526  goto end;
527  }
528  if (!verify_expr(e)) {
529  av_expr_free(e);
530  ret = AVERROR(EINVAL);
531  goto end;
532  }
533  *expr = e;
534 end:
535  av_free(w);
536  return ret;
537 }
538 
539 double av_expr_eval(AVExpr *e, const double *const_values, void *opaque)
540 {
541  Parser p = { 0 };
542 
544  p.opaque = opaque;
545  return eval_expr(&p, e);
546 }
547 
548 int av_expr_parse_and_eval(double *d, const char *s,
549  const char * const *const_names, const double *const_values,
550  const char * const *func1_names, double (* const *funcs1)(void *, double),
551  const char * const *func2_names, double (* const *funcs2)(void *, double, double),
552  void *opaque, int log_offset, void *log_ctx)
553 {
554  AVExpr *e = NULL;
555  int ret = av_expr_parse(&e, s, const_names, func1_names, funcs1, func2_names, funcs2, log_offset, log_ctx);
556 
557  if (ret < 0) {
558  *d = NAN;
559  return ret;
560  }
561  *d = av_expr_eval(e, const_values, opaque);
562  av_expr_free(e);
563  return isnan(*d) ? AVERROR(EINVAL) : 0;
564 }
565 
566 #ifdef TEST
567 #include <string.h>
568 
569 static const double const_values[] = {
570  M_PI,
571  M_E,
572  0
573 };
574 
575 static const char *const const_names[] = {
576  "PI",
577  "E",
578  0
579 };
580 
581 int main(int argc, char **argv)
582 {
583  int i;
584  double d;
585  const char *const *expr;
586  static const char *const exprs[] = {
587  "",
588  "1;2",
589  "-20",
590  "-PI",
591  "+PI",
592  "1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)",
593  "80G/80Gi",
594  "1k",
595  "1Gi",
596  "1gi",
597  "1GiFoo",
598  "1k+1k",
599  "1Gi*3foo",
600  "foo",
601  "foo(",
602  "foo()",
603  "foo)",
604  "sin",
605  "sin(",
606  "sin()",
607  "sin)",
608  "sin 10",
609  "sin(1,2,3)",
610  "sin(1 )",
611  "1",
612  "1foo",
613  "bar + PI + E + 100f*2 + foo",
614  "13k + 12f - foo(1, 2)",
615  "1gi",
616  "1Gi",
617  "st(0, 123)",
618  "st(1, 123); ld(1)",
619  "lte(0, 1)",
620  "lte(1, 1)",
621  "lte(1, 0)",
622  "lt(0, 1)",
623  "lt(1, 1)",
624  "gt(1, 0)",
625  "gt(2, 7)",
626  "gte(122, 122)",
627  /* compute 1+2+...+N */
628  "st(0, 1); while(lte(ld(0), 100), st(1, ld(1)+ld(0));st(0, ld(0)+1)); ld(1)",
629  /* compute Fib(N) */
630  "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)",
631  "while(0, 10)",
632  "st(0, 1); while(lte(ld(0),100), st(1, ld(1)+ld(0)); st(0, ld(0)+1))",
633  "isnan(1)",
634  "isnan(NAN)",
635  "isnan(INF)",
636  "isinf(1)",
637  "isinf(NAN)",
638  "isinf(INF)",
639  "floor(NAN)",
640  "floor(123.123)",
641  "floor(-123.123)",
642  "trunc(123.123)",
643  "trunc(-123.123)",
644  "ceil(123.123)",
645  "ceil(-123.123)",
646  "sqrt(1764)",
647  "isnan(sqrt(-1))",
648  "not(1)",
649  "not(NAN)",
650  "not(0)",
651  "6.0206dB",
652  "-3.0103dB",
653  NULL
654  };
655 
656  for (expr = exprs; *expr; expr++) {
657  printf("Evaluating '%s'\n", *expr);
658  av_expr_parse_and_eval(&d, *expr,
659  const_names, const_values,
660  NULL, NULL, NULL, NULL, NULL, 0, NULL);
661  if (isnan(d))
662  printf("'%s' -> nan\n\n", *expr);
663  else
664  printf("'%s' -> %f\n\n", *expr, d);
665  }
666 
667  av_expr_parse_and_eval(&d, "1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)",
668  const_names, const_values,
669  NULL, NULL, NULL, NULL, NULL, 0, NULL);
670  printf("%f == 12.7\n", d);
671  av_expr_parse_and_eval(&d, "80G/80Gi",
672  const_names, const_values,
673  NULL, NULL, NULL, NULL, NULL, 0, NULL);
674  printf("%f == 0.931322575\n", d);
675 
676  if (argc > 1 && !strcmp(argv[1], "-t")) {
677  for (i = 0; i < 1050; i++) {
678  START_TIMER;
679  av_expr_parse_and_eval(&d, "1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)",
680  const_names, const_values,
681  NULL, NULL, NULL, NULL, NULL, 0, NULL);
682  STOP_TIMER("av_expr_parse_and_eval");
683  }
684  }
685 
686  return 0;
687 }
688 #endif
#define VARS
Definition: eval.c:48
static int verify_expr(AVExpr *e)
Definition: eval.c:466
const char *const * func1_names
Definition: eval.c:42
struct AVExpr * param[2]
Definition: eval.c:141
void * av_malloc(size_t size)
Allocate a block of size bytes with alignment suitable for all memory accesses (including vectors if ...
Definition: mem.c:61
external API header
int 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)
Parse an expression.
Definition: eval.c:489
void * log_ctx
Definition: eval.c:47
void av_freep(void *arg)
Free a memory block which has been allocated with av_malloc(z)() or av_realloc() and set the pointer ...
Definition: mem.c:151
static int parse_dB(AVExpr **e, Parser *p, int *sign)
Definition: eval.c:346
static av_always_inline av_const int isnan(float x)
Definition: libm.h:85
static int parse_expr(AVExpr **e, Parser *p)
Definition: eval.c:436
#define b
Definition: input.c:52
Definition: eval.c:35
#define NAN
Definition: math.h:7
enum AVExpr::@110 type
static double(*const funcs1[])(void *, double)
Definition: vf_lut.c:199
Definition: eval.c:125
static AVExpr * new_eval_expr(int type, int value, AVExpr *p0, AVExpr *p1)
Definition: eval.c:327
double strtod(const char *, char **)
const char *const * const_names
Definition: eval.c:40
static const double const_values[]
Definition: opt.c:86
double(* func1)(void *, double)
Definition: eval.c:138
static int parse_pow(AVExpr **e, Parser *p, int *sign)
Definition: eval.c:339
static int parse_factor(AVExpr **e, Parser *p)
Definition: eval.c:361
av_default_item_name
Definition: eval.c:52
static int parse_subexpr(AVExpr **e, Parser *p)
Definition: eval.c:412
double(* func2)(void *, double, double)
Definition: eval.c:139
int 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)
Parse and evaluate an expression.
Definition: eval.c:548
const double * const_values
Definition: eval.c:39
void av_free(void *ptr)
Free a memory block which has been allocated with av_malloc(z)() or av_realloc(). ...
Definition: mem.c:139
#define IS_IDENTIFIER_CHAR(c)
Definition: eval.c:113
int const_index
Definition: eval.c:136
#define s0
Definition: regdef.h:37
static int parse_term(AVExpr **e, Parser *p)
Definition: eval.c:388
void av_log(void *avcl, int level, const char *fmt,...)
Definition: log.c:146
int main(int argc, char **argv)
Definition: avconv.c:2348
static const char *const const_names[]
Definition: opt.c:93
struct Parser Parser
static const int8_t si_prefixes['z'- 'E'+1]
Definition: eval.c:54
#define M_E
Definition: ratecontrol.c:39
static av_always_inline av_const double trunc(double x)
Definition: libm.h:165
static int strmatch(const char *s, const char *prefix)
Definition: eval.c:115
static int parse_primary(AVExpr **e, Parser *p)
Definition: eval.c:200
LIBAVUTIL_VERSION_INT
Definition: eval.c:52
void * opaque
Definition: eval.c:45
double av_strtod(const char *numstr, char **tail)
Parse the string in numstr and return its value as a double.
Definition: eval.c:77
const AVClass * class
Definition: eval.c:36
NULL
Definition: eval.c:52
static double eval_expr(Parser *p, AVExpr *e)
Definition: eval.c:144
void av_expr_free(AVExpr *e)
Free a parsed expression previously created with av_expr_parse().
Definition: eval.c:192
#define START_TIMER
Definition: timer.h:74
char * s
Definition: eval.c:38
Describe the class of an AVClass context structure.
Definition: log.h:33
double(*const funcs1)(void *, double a)
Definition: eval.c:41
const char *const * func2_names
Definition: eval.c:44
common internal and external API header
double var[VARS]
Definition: eval.c:49
int stack_index
Definition: eval.c:37
#define STOP_TIMER(id)
Definition: timer.h:75
double(*const funcs2)(void *, double a, double b)
Definition: eval.c:43
double av_expr_eval(AVExpr *e, const double *const_values, void *opaque)
Evaluate a previously parsed expression.
Definition: eval.c:539
double(* func0)(double)
Definition: eval.c:137
static av_always_inline av_const int isinf(float x)
Definition: libm.h:75
int log_offset
Definition: eval.c:46
union AVExpr::@111 a
void * av_mallocz(size_t size)
Allocate a block of size bytes with alignment suitable for all memory accesses (including vectors if ...
Definition: mem.c:158
double value
Definition: eval.c:134
simple arithmetic expression evaluator