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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 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 "log.h"
35 #include "mathematics.h"
36 #include "time.h"
37 #include "avstring.h"
38 #include "timer.h"
39 
40 typedef struct Parser {
41  const AVClass *class;
43  char *s;
44  const double *const_values;
45  const char * const *const_names; // NULL terminated
46  double (* const *funcs1)(void *, double a); // NULL terminated
47  const char * const *func1_names; // NULL terminated
48  double (* const *funcs2)(void *, double a, double b); // NULL terminated
49  const char * const *func2_names; // NULL terminated
50  void *opaque;
52  void *log_ctx;
53 #define VARS 10
54  double *var;
55 } Parser;
56 
57 static const AVClass eval_class = { "Eval", av_default_item_name, NULL, LIBAVUTIL_VERSION_INT, offsetof(Parser,log_offset), offsetof(Parser,log_ctx) };
58 
59 static const int8_t si_prefixes['z' - 'E' + 1] = {
60  ['y'-'E']= -24,
61  ['z'-'E']= -21,
62  ['a'-'E']= -18,
63  ['f'-'E']= -15,
64  ['p'-'E']= -12,
65  ['n'-'E']= - 9,
66  ['u'-'E']= - 6,
67  ['m'-'E']= - 3,
68  ['c'-'E']= - 2,
69  ['d'-'E']= - 1,
70  ['h'-'E']= 2,
71  ['k'-'E']= 3,
72  ['K'-'E']= 3,
73  ['M'-'E']= 6,
74  ['G'-'E']= 9,
75  ['T'-'E']= 12,
76  ['P'-'E']= 15,
77  ['E'-'E']= 18,
78  ['Z'-'E']= 21,
79  ['Y'-'E']= 24,
80 };
81 
82 static const struct {
83  const char *name;
84  double value;
85 } constants[] = {
86  { "E", M_E },
87  { "PI", M_PI },
88  { "PHI", M_PHI },
89  { "QP2LAMBDA", FF_QP2LAMBDA },
90 };
91 
92 double av_strtod(const char *numstr, char **tail)
93 {
94  double d;
95  char *next;
96  if(numstr[0]=='0' && (numstr[1]|0x20)=='x') {
97  d = strtoul(numstr, &next, 16);
98  } else
99  d = strtod(numstr, &next);
100  /* if parsing succeeded, check for and interpret postfixes */
101  if (next!=numstr) {
102  if (next[0] == 'd' && next[1] == 'B') {
103  /* treat dB as decibels instead of decibytes */
104  d = pow(10, d / 20);
105  next += 2;
106  } else if (*next >= 'E' && *next <= 'z') {
107  int e= si_prefixes[*next - 'E'];
108  if (e) {
109  if (next[1] == 'i') {
110  d*= pow( 2, e/0.3);
111  next+=2;
112  } else {
113  d*= pow(10, e);
114  next++;
115  }
116  }
117  }
118 
119  if (*next=='B') {
120  d*=8;
121  next++;
122  }
123  }
124  /* if requested, fill in tail with the position after the last parsed
125  character */
126  if (tail)
127  *tail = next;
128  return d;
129 }
130 
131 #define IS_IDENTIFIER_CHAR(c) ((c) - '0' <= 9U || (c) - 'a' <= 25U || (c) - 'A' <= 25U || (c) == '_')
132 
133 static int strmatch(const char *s, const char *prefix)
134 {
135  int i;
136  for (i=0; prefix[i]; i++) {
137  if (prefix[i] != s[i]) return 0;
138  }
139  /* return 1 only if the s identifier is terminated */
140  return !IS_IDENTIFIER_CHAR(s[i]);
141 }
142 
143 struct AVExpr {
144  enum {
152  } type;
153  double value; // is sign in other types
154  union {
156  double (*func0)(double);
157  double (*func1)(void *, double);
158  double (*func2)(void *, double, double);
159  } a;
160  struct AVExpr *param[3];
161  double *var;
162 };
163 
164 static double etime(double v)
165 {
166  return av_gettime() * 0.000001;
167 }
168 
169 static double eval_expr(Parser *p, AVExpr *e)
170 {
171  switch (e->type) {
172  case e_value: return e->value;
173  case e_const: return e->value * p->const_values[e->a.const_index];
174  case e_func0: return e->value * e->a.func0(eval_expr(p, e->param[0]));
175  case e_func1: return e->value * e->a.func1(p->opaque, eval_expr(p, e->param[0]));
176  case e_func2: return e->value * e->a.func2(p->opaque, eval_expr(p, e->param[0]), eval_expr(p, e->param[1]));
177  case e_squish: return 1/(1+exp(4*eval_expr(p, e->param[0])));
178  case e_gauss: { double d = eval_expr(p, e->param[0]); return exp(-d*d/2)/sqrt(2*M_PI); }
179  case e_ld: return e->value * p->var[av_clip(eval_expr(p, e->param[0]), 0, VARS-1)];
180  case e_isnan: return e->value * !!isnan(eval_expr(p, e->param[0]));
181  case e_isinf: return e->value * !!isinf(eval_expr(p, e->param[0]));
182  case e_floor: return e->value * floor(eval_expr(p, e->param[0]));
183  case e_ceil : return e->value * ceil (eval_expr(p, e->param[0]));
184  case e_trunc: return e->value * trunc(eval_expr(p, e->param[0]));
185  case e_sqrt: return e->value * sqrt (eval_expr(p, e->param[0]));
186  case e_not: return e->value * (eval_expr(p, e->param[0]) == 0);
187  case e_if: 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_ifnot: return e->value * (!eval_expr(p, e->param[0]) ? eval_expr(p, e->param[1]) :
190  e->param[2] ? eval_expr(p, e->param[2]) : 0);
191  case e_clip: {
192  double x = eval_expr(p, e->param[0]);
193  double min = eval_expr(p, e->param[1]), max = eval_expr(p, e->param[2]);
194  if (isnan(min) || isnan(max) || isnan(x) || min > max)
195  return NAN;
196  return e->value * av_clipd(eval_expr(p, e->param[0]), min, max);
197  }
198  case e_between: {
199  double d = eval_expr(p, e->param[0]);
200  return e->value * (d >= eval_expr(p, e->param[1]) &&
201  d <= eval_expr(p, e->param[2]));
202  }
203  case e_print: {
204  double x = eval_expr(p, e->param[0]);
205  int level = e->param[1] ? av_clip(eval_expr(p, e->param[1]), INT_MIN, INT_MAX) : AV_LOG_INFO;
206  av_log(p, level, "%f\n", x);
207  return x;
208  }
209  case e_random:{
210  int idx= av_clip(eval_expr(p, e->param[0]), 0, VARS-1);
211  uint64_t r= isnan(p->var[idx]) ? 0 : p->var[idx];
212  r= r*1664525+1013904223;
213  p->var[idx]= r;
214  return e->value * (r * (1.0/UINT64_MAX));
215  }
216  case e_while: {
217  double d = NAN;
218  while (eval_expr(p, e->param[0]))
219  d=eval_expr(p, e->param[1]);
220  return d;
221  }
222  case e_taylor: {
223  double t = 1, d = 0, v;
224  double x = eval_expr(p, e->param[1]);
225  int id = e->param[2] ? av_clip(eval_expr(p, e->param[2]), 0, VARS-1) : 0;
226  int i;
227  double var0 = p->var[id];
228  for(i=0; i<1000; i++) {
229  double ld = d;
230  p->var[id] = i;
231  v = eval_expr(p, e->param[0]);
232  d += t*v;
233  if(ld==d && v)
234  break;
235  t *= x / (i+1);
236  }
237  p->var[id] = var0;
238  return d;
239  }
240  case e_root: {
241  int i, j;
242  double low = -1, high = -1, v, low_v = -DBL_MAX, high_v = DBL_MAX;
243  double var0 = p->var[0];
244  double x_max = eval_expr(p, e->param[1]);
245  for(i=-1; i<1024; i++) {
246  if(i<255) {
247  p->var[0] = av_reverse[i&255]*x_max/255;
248  } else {
249  p->var[0] = x_max*pow(0.9, i-255);
250  if (i&1) p->var[0] *= -1;
251  if (i&2) p->var[0] += low;
252  else p->var[0] += high;
253  }
254  v = eval_expr(p, e->param[0]);
255  if (v<=0 && v>low_v) {
256  low = p->var[0];
257  low_v = v;
258  }
259  if (v>=0 && v<high_v) {
260  high = p->var[0];
261  high_v = v;
262  }
263  if (low>=0 && high>=0){
264  for (j=0; j<1000; j++) {
265  p->var[0] = (low+high)*0.5;
266  if (low == p->var[0] || high == p->var[0])
267  break;
268  v = eval_expr(p, e->param[0]);
269  if (v<=0) low = p->var[0];
270  if (v>=0) high= p->var[0];
271  if (isnan(v)) {
272  low = high = v;
273  break;
274  }
275  }
276  break;
277  }
278  }
279  p->var[0] = var0;
280  return -low_v<high_v ? low : high;
281  }
282  default: {
283  double d = eval_expr(p, e->param[0]);
284  double d2 = eval_expr(p, e->param[1]);
285  switch (e->type) {
286  case e_mod: return e->value * (d - floor((!CONFIG_FTRAPV || d2) ? d / d2 : d * INFINITY) * d2);
287  case e_gcd: return e->value * av_gcd(d,d2);
288  case e_max: return e->value * (d > d2 ? d : d2);
289  case e_min: return e->value * (d < d2 ? d : d2);
290  case e_eq: return e->value * (d == d2 ? 1.0 : 0.0);
291  case e_gt: return e->value * (d > d2 ? 1.0 : 0.0);
292  case e_gte: return e->value * (d >= d2 ? 1.0 : 0.0);
293  case e_lt: return e->value * (d < d2 ? 1.0 : 0.0);
294  case e_lte: return e->value * (d <= d2 ? 1.0 : 0.0);
295  case e_pow: return e->value * pow(d, d2);
296  case e_mul: return e->value * (d * d2);
297  case e_div: return e->value * ((!CONFIG_FTRAPV || d2 ) ? (d / d2) : d * INFINITY);
298  case e_add: return e->value * (d + d2);
299  case e_last:return e->value * d2;
300  case e_st : return e->value * (p->var[av_clip(d, 0, VARS-1)]= d2);
301  case e_hypot:return e->value * (sqrt(d*d + d2*d2));
302  case e_bitand: return isnan(d) || isnan(d2) ? NAN : e->value * ((long int)d & (long int)d2);
303  case e_bitor: return isnan(d) || isnan(d2) ? NAN : e->value * ((long int)d | (long int)d2);
304  }
305  }
306  }
307  return NAN;
308 }
309 
310 static int parse_expr(AVExpr **e, Parser *p);
311 
313 {
314  if (!e) return;
315  av_expr_free(e->param[0]);
316  av_expr_free(e->param[1]);
317  av_expr_free(e->param[2]);
318  av_freep(&e->var);
319  av_freep(&e);
320 }
321 
322 static int parse_primary(AVExpr **e, Parser *p)
323 {
324  AVExpr *d = av_mallocz(sizeof(AVExpr));
325  char *next = p->s, *s0 = p->s;
326  int ret, i;
327 
328  if (!d)
329  return AVERROR(ENOMEM);
330 
331  /* number */
332  d->value = av_strtod(p->s, &next);
333  if (next != p->s) {
334  d->type = e_value;
335  p->s= next;
336  *e = d;
337  return 0;
338  }
339  d->value = 1;
340 
341  /* named constants */
342  for (i=0; p->const_names && p->const_names[i]; i++) {
343  if (strmatch(p->s, p->const_names[i])) {
344  p->s+= strlen(p->const_names[i]);
345  d->type = e_const;
346  d->a.const_index = i;
347  *e = d;
348  return 0;
349  }
350  }
351  for (i = 0; i < FF_ARRAY_ELEMS(constants); i++) {
352  if (strmatch(p->s, constants[i].name)) {
353  p->s += strlen(constants[i].name);
354  d->type = e_value;
355  d->value = constants[i].value;
356  *e = d;
357  return 0;
358  }
359  }
360 
361  p->s= strchr(p->s, '(');
362  if (p->s==NULL) {
363  av_log(p, AV_LOG_ERROR, "Undefined constant or missing '(' in '%s'\n", s0);
364  p->s= next;
365  av_expr_free(d);
366  return AVERROR(EINVAL);
367  }
368  p->s++; // "("
369  if (*next == '(') { // special case do-nothing
370  av_freep(&d);
371  if ((ret = parse_expr(&d, p)) < 0)
372  return ret;
373  if (p->s[0] != ')') {
374  av_log(p, AV_LOG_ERROR, "Missing ')' in '%s'\n", s0);
375  av_expr_free(d);
376  return AVERROR(EINVAL);
377  }
378  p->s++; // ")"
379  *e = d;
380  return 0;
381  }
382  if ((ret = parse_expr(&(d->param[0]), p)) < 0) {
383  av_expr_free(d);
384  return ret;
385  }
386  if (p->s[0]== ',') {
387  p->s++; // ","
388  parse_expr(&d->param[1], p);
389  }
390  if (p->s[0]== ',') {
391  p->s++; // ","
392  parse_expr(&d->param[2], p);
393  }
394  if (p->s[0] != ')') {
395  av_log(p, AV_LOG_ERROR, "Missing ')' or too many args in '%s'\n", s0);
396  av_expr_free(d);
397  return AVERROR(EINVAL);
398  }
399  p->s++; // ")"
400 
401  d->type = e_func0;
402  if (strmatch(next, "sinh" )) d->a.func0 = sinh;
403  else if (strmatch(next, "cosh" )) d->a.func0 = cosh;
404  else if (strmatch(next, "tanh" )) d->a.func0 = tanh;
405  else if (strmatch(next, "sin" )) d->a.func0 = sin;
406  else if (strmatch(next, "cos" )) d->a.func0 = cos;
407  else if (strmatch(next, "tan" )) d->a.func0 = tan;
408  else if (strmatch(next, "atan" )) d->a.func0 = atan;
409  else if (strmatch(next, "asin" )) d->a.func0 = asin;
410  else if (strmatch(next, "acos" )) d->a.func0 = acos;
411  else if (strmatch(next, "exp" )) d->a.func0 = exp;
412  else if (strmatch(next, "log" )) d->a.func0 = log;
413  else if (strmatch(next, "abs" )) d->a.func0 = fabs;
414  else if (strmatch(next, "time" )) d->a.func0 = etime;
415  else if (strmatch(next, "squish")) d->type = e_squish;
416  else if (strmatch(next, "gauss" )) d->type = e_gauss;
417  else if (strmatch(next, "mod" )) d->type = e_mod;
418  else if (strmatch(next, "max" )) d->type = e_max;
419  else if (strmatch(next, "min" )) d->type = e_min;
420  else if (strmatch(next, "eq" )) d->type = e_eq;
421  else if (strmatch(next, "gte" )) d->type = e_gte;
422  else if (strmatch(next, "gt" )) d->type = e_gt;
423  else if (strmatch(next, "lte" )) d->type = e_lte;
424  else if (strmatch(next, "lt" )) d->type = e_lt;
425  else if (strmatch(next, "ld" )) d->type = e_ld;
426  else if (strmatch(next, "isnan" )) d->type = e_isnan;
427  else if (strmatch(next, "isinf" )) d->type = e_isinf;
428  else if (strmatch(next, "st" )) d->type = e_st;
429  else if (strmatch(next, "while" )) d->type = e_while;
430  else if (strmatch(next, "taylor")) d->type = e_taylor;
431  else if (strmatch(next, "root" )) d->type = e_root;
432  else if (strmatch(next, "floor" )) d->type = e_floor;
433  else if (strmatch(next, "ceil" )) d->type = e_ceil;
434  else if (strmatch(next, "trunc" )) d->type = e_trunc;
435  else if (strmatch(next, "sqrt" )) d->type = e_sqrt;
436  else if (strmatch(next, "not" )) d->type = e_not;
437  else if (strmatch(next, "pow" )) d->type = e_pow;
438  else if (strmatch(next, "print" )) d->type = e_print;
439  else if (strmatch(next, "random")) d->type = e_random;
440  else if (strmatch(next, "hypot" )) d->type = e_hypot;
441  else if (strmatch(next, "gcd" )) d->type = e_gcd;
442  else if (strmatch(next, "if" )) d->type = e_if;
443  else if (strmatch(next, "ifnot" )) d->type = e_ifnot;
444  else if (strmatch(next, "bitand")) d->type = e_bitand;
445  else if (strmatch(next, "bitor" )) d->type = e_bitor;
446  else if (strmatch(next, "between"))d->type = e_between;
447  else if (strmatch(next, "clip" )) d->type = e_clip;
448  else {
449  for (i=0; p->func1_names && p->func1_names[i]; i++) {
450  if (strmatch(next, p->func1_names[i])) {
451  d->a.func1 = p->funcs1[i];
452  d->type = e_func1;
453  *e = d;
454  return 0;
455  }
456  }
457 
458  for (i=0; p->func2_names && p->func2_names[i]; i++) {
459  if (strmatch(next, p->func2_names[i])) {
460  d->a.func2 = p->funcs2[i];
461  d->type = e_func2;
462  *e = d;
463  return 0;
464  }
465  }
466 
467  av_log(p, AV_LOG_ERROR, "Unknown function in '%s'\n", s0);
468  av_expr_free(d);
469  return AVERROR(EINVAL);
470  }
471 
472  *e = d;
473  return 0;
474 }
475 
476 static AVExpr *make_eval_expr(int type, int value, AVExpr *p0, AVExpr *p1)
477 {
478  AVExpr *e = av_mallocz(sizeof(AVExpr));
479  if (!e)
480  return NULL;
481  e->type =type ;
482  e->value =value ;
483  e->param[0] =p0 ;
484  e->param[1] =p1 ;
485  return e;
486 }
487 
488 static int parse_pow(AVExpr **e, Parser *p, int *sign)
489 {
490  *sign= (*p->s == '+') - (*p->s == '-');
491  p->s += *sign&1;
492  return parse_primary(e, p);
493 }
494 
495 static int parse_dB(AVExpr **e, Parser *p, int *sign)
496 {
497  /* do not filter out the negative sign when parsing a dB value.
498  for example, -3dB is not the same as -(3dB) */
499  if (*p->s == '-') {
500  char *next;
501  double av_unused ignored = strtod(p->s, &next);
502  if (next != p->s && next[0] == 'd' && next[1] == 'B') {
503  *sign = 0;
504  return parse_primary(e, p);
505  }
506  }
507  return parse_pow(e, p, sign);
508 }
509 
510 static int parse_factor(AVExpr **e, Parser *p)
511 {
512  int sign, sign2, ret;
513  AVExpr *e0, *e1, *e2;
514  if ((ret = parse_dB(&e0, p, &sign)) < 0)
515  return ret;
516  while(p->s[0]=='^'){
517  e1 = e0;
518  p->s++;
519  if ((ret = parse_dB(&e2, p, &sign2)) < 0) {
520  av_expr_free(e1);
521  return ret;
522  }
523  e0 = make_eval_expr(e_pow, 1, e1, e2);
524  if (!e0) {
525  av_expr_free(e1);
526  av_expr_free(e2);
527  return AVERROR(ENOMEM);
528  }
529  if (e0->param[1]) e0->param[1]->value *= (sign2|1);
530  }
531  if (e0) e0->value *= (sign|1);
532 
533  *e = e0;
534  return 0;
535 }
536 
537 static int parse_term(AVExpr **e, Parser *p)
538 {
539  int ret;
540  AVExpr *e0, *e1, *e2;
541  if ((ret = parse_factor(&e0, p)) < 0)
542  return ret;
543  while (p->s[0]=='*' || p->s[0]=='/') {
544  int c= *p->s++;
545  e1 = e0;
546  if ((ret = parse_factor(&e2, p)) < 0) {
547  av_expr_free(e1);
548  return ret;
549  }
550  e0 = make_eval_expr(c == '*' ? e_mul : e_div, 1, e1, e2);
551  if (!e0) {
552  av_expr_free(e1);
553  av_expr_free(e2);
554  return AVERROR(ENOMEM);
555  }
556  }
557  *e = e0;
558  return 0;
559 }
560 
561 static int parse_subexpr(AVExpr **e, Parser *p)
562 {
563  int ret;
564  AVExpr *e0, *e1, *e2;
565  if ((ret = parse_term(&e0, p)) < 0)
566  return ret;
567  while (*p->s == '+' || *p->s == '-') {
568  e1 = e0;
569  if ((ret = parse_term(&e2, p)) < 0) {
570  av_expr_free(e1);
571  return ret;
572  }
573  e0 = make_eval_expr(e_add, 1, e1, e2);
574  if (!e0) {
575  av_expr_free(e1);
576  av_expr_free(e2);
577  return AVERROR(ENOMEM);
578  }
579  };
580 
581  *e = e0;
582  return 0;
583 }
584 
585 static int parse_expr(AVExpr **e, Parser *p)
586 {
587  int ret;
588  AVExpr *e0, *e1, *e2;
589  if (p->stack_index <= 0) //protect against stack overflows
590  return AVERROR(EINVAL);
591  p->stack_index--;
592 
593  if ((ret = parse_subexpr(&e0, p)) < 0)
594  return ret;
595  while (*p->s == ';') {
596  p->s++;
597  e1 = e0;
598  if ((ret = parse_subexpr(&e2, p)) < 0) {
599  av_expr_free(e1);
600  return ret;
601  }
602  e0 = make_eval_expr(e_last, 1, e1, e2);
603  if (!e0) {
604  av_expr_free(e1);
605  av_expr_free(e2);
606  return AVERROR(ENOMEM);
607  }
608  };
609 
610  p->stack_index++;
611  *e = e0;
612  return 0;
613 }
614 
615 static int verify_expr(AVExpr *e)
616 {
617  if (!e) return 0;
618  switch (e->type) {
619  case e_value:
620  case e_const: return 1;
621  case e_func0:
622  case e_func1:
623  case e_squish:
624  case e_ld:
625  case e_gauss:
626  case e_isnan:
627  case e_isinf:
628  case e_floor:
629  case e_ceil:
630  case e_trunc:
631  case e_sqrt:
632  case e_not:
633  case e_random:
634  return verify_expr(e->param[0]) && !e->param[1];
635  case e_print:
636  return verify_expr(e->param[0])
637  && (!e->param[1] || verify_expr(e->param[1]));
638  case e_if:
639  case e_ifnot:
640  case e_taylor:
641  return verify_expr(e->param[0]) && verify_expr(e->param[1])
642  && (!e->param[2] || verify_expr(e->param[2]));
643  case e_between:
644  case e_clip:
645  return verify_expr(e->param[0]) &&
646  verify_expr(e->param[1]) &&
647  verify_expr(e->param[2]);
648  default: return verify_expr(e->param[0]) && verify_expr(e->param[1]) && !e->param[2];
649  }
650 }
651 
652 int av_expr_parse(AVExpr **expr, const char *s,
653  const char * const *const_names,
654  const char * const *func1_names, double (* const *funcs1)(void *, double),
655  const char * const *func2_names, double (* const *funcs2)(void *, double, double),
656  int log_offset, void *log_ctx)
657 {
658  Parser p = { 0 };
659  AVExpr *e = NULL;
660  char *w = av_malloc(strlen(s) + 1);
661  char *wp = w;
662  const char *s0 = s;
663  int ret = 0;
664 
665  if (!w)
666  return AVERROR(ENOMEM);
667 
668  while (*s)
669  if (!av_isspace(*s++)) *wp++ = s[-1];
670  *wp++ = 0;
671 
672  p.class = &eval_class;
673  p.stack_index=100;
674  p.s= w;
675  p.const_names = const_names;
676  p.funcs1 = funcs1;
678  p.funcs2 = funcs2;
679  p.func2_names = func2_names;
680  p.log_offset = log_offset;
681  p.log_ctx = log_ctx;
682 
683  if ((ret = parse_expr(&e, &p)) < 0)
684  goto end;
685  if (*p.s) {
686  av_expr_free(e);
687  av_log(&p, AV_LOG_ERROR, "Invalid chars '%s' at the end of expression '%s'\n", p.s, s0);
688  ret = AVERROR(EINVAL);
689  goto end;
690  }
691  if (!verify_expr(e)) {
692  av_expr_free(e);
693  ret = AVERROR(EINVAL);
694  goto end;
695  }
696  e->var= av_mallocz(sizeof(double) *VARS);
697  *expr = e;
698 end:
699  av_free(w);
700  return ret;
701 }
702 
703 double av_expr_eval(AVExpr *e, const double *const_values, void *opaque)
704 {
705  Parser p = { 0 };
706  p.var= e->var;
707 
708  p.const_values = const_values;
709  p.opaque = opaque;
710  return eval_expr(&p, e);
711 }
712 
713 int av_expr_parse_and_eval(double *d, const char *s,
714  const char * const *const_names, const double *const_values,
715  const char * const *func1_names, double (* const *funcs1)(void *, double),
716  const char * const *func2_names, double (* const *funcs2)(void *, double, double),
717  void *opaque, int log_offset, void *log_ctx)
718 {
719  AVExpr *e = NULL;
720  int ret = av_expr_parse(&e, s, const_names, func1_names, funcs1, func2_names, funcs2, log_offset, log_ctx);
721 
722  if (ret < 0) {
723  *d = NAN;
724  return ret;
725  }
726  *d = av_expr_eval(e, const_values, opaque);
727  av_expr_free(e);
728  return isnan(*d) ? AVERROR(EINVAL) : 0;
729 }
730 
731 #ifdef TEST
732 #include <string.h>
733 
734 static const double const_values[] = {
735  M_PI,
736  M_E,
737  0
738 };
739 
740 static const char *const const_names[] = {
741  "PI",
742  "E",
743  0
744 };
745 
746 int main(int argc, char **argv)
747 {
748  int i;
749  double d;
750  const char *const *expr;
751  static const char *const exprs[] = {
752  "",
753  "1;2",
754  "-20",
755  "-PI",
756  "+PI",
757  "1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)",
758  "80G/80Gi",
759  "1k",
760  "1Gi",
761  "1gi",
762  "1GiFoo",
763  "1k+1k",
764  "1Gi*3foo",
765  "foo",
766  "foo(",
767  "foo()",
768  "foo)",
769  "sin",
770  "sin(",
771  "sin()",
772  "sin)",
773  "sin 10",
774  "sin(1,2,3)",
775  "sin(1 )",
776  "1",
777  "1foo",
778  "bar + PI + E + 100f*2 + foo",
779  "13k + 12f - foo(1, 2)",
780  "1gi",
781  "1Gi",
782  "st(0, 123)",
783  "st(1, 123); ld(1)",
784  "lte(0, 1)",
785  "lte(1, 1)",
786  "lte(1, 0)",
787  "lt(0, 1)",
788  "lt(1, 1)",
789  "gt(1, 0)",
790  "gt(2, 7)",
791  "gte(122, 122)",
792  /* compute 1+2+...+N */
793  "st(0, 1); while(lte(ld(0), 100), st(1, ld(1)+ld(0));st(0, ld(0)+1)); ld(1)",
794  /* compute Fib(N) */
795  "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)",
796  "while(0, 10)",
797  "st(0, 1); while(lte(ld(0),100), st(1, ld(1)+ld(0)); st(0, ld(0)+1))",
798  "isnan(1)",
799  "isnan(NAN)",
800  "isnan(INF)",
801  "isinf(1)",
802  "isinf(NAN)",
803  "isinf(INF)",
804  "floor(NAN)",
805  "floor(123.123)",
806  "floor(-123.123)",
807  "trunc(123.123)",
808  "trunc(-123.123)",
809  "ceil(123.123)",
810  "ceil(-123.123)",
811  "sqrt(1764)",
812  "isnan(sqrt(-1))",
813  "not(1)",
814  "not(NAN)",
815  "not(0)",
816  "6.0206dB",
817  "-3.0103dB",
818  "pow(0,1.23)",
819  "pow(PI,1.23)",
820  "PI^1.23",
821  "pow(-1,1.23)",
822  "if(1, 2)",
823  "if(1, 1, 2)",
824  "if(0, 1, 2)",
825  "ifnot(0, 23)",
826  "ifnot(1, NaN) + if(0, 1)",
827  "ifnot(1, 1, 2)",
828  "ifnot(0, 1, 2)",
829  "taylor(1, 1)",
830  "taylor(eq(mod(ld(1),4),1)-eq(mod(ld(1),4),3), PI/2, 1)",
831  "root(sin(ld(0))-1, 2)",
832  "root(sin(ld(0))+6+sin(ld(0)/12)-log(ld(0)), 100)",
833  "7000000B*random(0)",
834  "squish(2)",
835  "gauss(0.1)",
836  "hypot(4,3)",
837  "gcd(30,55)*print(min(9,1))",
838  "bitor(42, 12)",
839  "bitand(42, 12)",
840  "bitand(NAN, 1)",
841  "between(10, -3, 10)",
842  "between(-4, -2, -1)",
843  "between(1,2)",
844  "clip(0, 2, 1)",
845  "clip(0/0, 1, 2)",
846  "clip(0, 0/0, 1)",
847  NULL
848  };
849 
850  for (expr = exprs; *expr; expr++) {
851  printf("Evaluating '%s'\n", *expr);
852  av_expr_parse_and_eval(&d, *expr,
853  const_names, const_values,
854  NULL, NULL, NULL, NULL, NULL, 0, NULL);
855  if (isnan(d))
856  printf("'%s' -> nan\n\n", *expr);
857  else
858  printf("'%s' -> %f\n\n", *expr, d);
859  }
860 
861  av_expr_parse_and_eval(&d, "1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)",
862  const_names, const_values,
863  NULL, NULL, NULL, NULL, NULL, 0, NULL);
864  printf("%f == 12.7\n", d);
865  av_expr_parse_and_eval(&d, "80G/80Gi",
866  const_names, const_values,
867  NULL, NULL, NULL, NULL, NULL, 0, NULL);
868  printf("%f == 0.931322575\n", d);
869 
870  if (argc > 1 && !strcmp(argv[1], "-t")) {
871  for (i = 0; i < 1050; i++) {
872  START_TIMER;
873  av_expr_parse_and_eval(&d, "1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)",
874  const_names, const_values,
875  NULL, NULL, NULL, NULL, NULL, 0, NULL);
876  STOP_TIMER("av_expr_parse_and_eval");
877  }
878  }
879 
880  return 0;
881 }
882 #endif