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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;
42  int stack_index;
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;
51  int log_offset;
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 };
90 
91 double av_strtod(const char *numstr, char **tail)
92 {
93  double d;
94  char *next;
95  if(numstr[0]=='0' && (numstr[1]|0x20)=='x') {
96  d = strtoul(numstr, &next, 16);
97  } else
98  d = strtod(numstr, &next);
99  /* if parsing succeeded, check for and interpret postfixes */
100  if (next!=numstr) {
101  if (next[0] == 'd' && next[1] == 'B') {
102  /* treat dB as decibels instead of decibytes */
103  d = pow(10, d / 20);
104  next += 2;
105  } else if (*next >= 'E' && *next <= 'z') {
106  int e= si_prefixes[*next - 'E'];
107  if (e) {
108  if (next[1] == 'i') {
109  d*= pow( 2, e/0.3);
110  next+=2;
111  } else {
112  d*= pow(10, e);
113  next++;
114  }
115  }
116  }
117 
118  if (*next=='B') {
119  d*=8;
120  next++;
121  }
122  }
123  /* if requested, fill in tail with the position after the last parsed
124  character */
125  if (tail)
126  *tail = next;
127  return d;
128 }
129 
130 #define IS_IDENTIFIER_CHAR(c) ((c) - '0' <= 9U || (c) - 'a' <= 25U || (c) - 'A' <= 25U || (c) == '_')
131 
132 static int strmatch(const char *s, const char *prefix)
133 {
134  int i;
135  for (i=0; prefix[i]; i++) {
136  if (prefix[i] != s[i]) return 0;
137  }
138  /* return 1 only if the s identifier is terminated */
139  return !IS_IDENTIFIER_CHAR(s[i]);
140 }
141 
142 struct AVExpr {
143  enum {
144  e_value, e_const, e_func0, e_func1, e_func2,
145  e_squish, e_gauss, e_ld, e_isnan, e_isinf,
146  e_mod, e_max, e_min, e_eq, e_gt, e_gte, e_lte, e_lt,
147  e_pow, e_mul, e_div, e_add,
148  e_last, e_st, e_while, e_taylor, e_root, e_floor, e_ceil, e_trunc,
149  e_sqrt, e_not, e_random, e_hypot, e_gcd,
150  e_if, e_ifnot, e_print, e_bitand, e_bitor, e_between,
151  } type;
152  double value; // is sign in other types
153  union {
154  int const_index;
155  double (*func0)(double);
156  double (*func1)(void *, double);
157  double (*func2)(void *, double, double);
158  } a;
159  struct AVExpr *param[3];
160  double *var;
161 };
162 
163 static double etime(double v)
164 {
165  return av_gettime() * 0.000001;
166 }
167 
168 static double eval_expr(Parser *p, AVExpr *e)
169 {
170  switch (e->type) {
171  case e_value: return e->value;
172  case e_const: return e->value * p->const_values[e->a.const_index];
173  case e_func0: return e->value * e->a.func0(eval_expr(p, e->param[0]));
174  case e_func1: return e->value * e->a.func1(p->opaque, eval_expr(p, e->param[0]));
175  case e_func2: return e->value * e->a.func2(p->opaque, eval_expr(p, e->param[0]), eval_expr(p, e->param[1]));
176  case e_squish: return 1/(1+exp(4*eval_expr(p, e->param[0])));
177  case e_gauss: { double d = eval_expr(p, e->param[0]); return exp(-d*d/2)/sqrt(2*M_PI); }
178  case e_ld: return e->value * p->var[av_clip(eval_expr(p, e->param[0]), 0, VARS-1)];
179  case e_isnan: return e->value * !!isnan(eval_expr(p, e->param[0]));
180  case e_isinf: return e->value * !!isinf(eval_expr(p, e->param[0]));
181  case e_floor: return e->value * floor(eval_expr(p, e->param[0]));
182  case e_ceil : return e->value * ceil (eval_expr(p, e->param[0]));
183  case e_trunc: return e->value * trunc(eval_expr(p, e->param[0]));
184  case e_sqrt: return e->value * sqrt (eval_expr(p, e->param[0]));
185  case e_not: return e->value * (eval_expr(p, e->param[0]) == 0);
186  case e_if: return e->value * (eval_expr(p, e->param[0]) ? eval_expr(p, e->param[1]) :
187  e->param[2] ? eval_expr(p, e->param[2]) : 0);
188  case e_ifnot: return e->value * (!eval_expr(p, e->param[0]) ? eval_expr(p, e->param[1]) :
189  e->param[2] ? eval_expr(p, e->param[2]) : 0);
190  case e_between: {
191  double d = eval_expr(p, e->param[0]);
192  return e->value * (d >= eval_expr(p, e->param[1]) &&
193  d <= eval_expr(p, e->param[2]));
194  }
195  case e_print: {
196  double x = eval_expr(p, e->param[0]);
197  int level = e->param[1] ? av_clip(eval_expr(p, e->param[1]), INT_MIN, INT_MAX) : AV_LOG_INFO;
198  av_log(p, level, "%f\n", x);
199  return x;
200  }
201  case e_random:{
202  int idx= av_clip(eval_expr(p, e->param[0]), 0, VARS-1);
203  uint64_t r= isnan(p->var[idx]) ? 0 : p->var[idx];
204  r= r*1664525+1013904223;
205  p->var[idx]= r;
206  return e->value * (r * (1.0/UINT64_MAX));
207  }
208  case e_while: {
209  double d = NAN;
210  while (eval_expr(p, e->param[0]))
211  d=eval_expr(p, e->param[1]);
212  return d;
213  }
214  case e_taylor: {
215  double t = 1, d = 0, v;
216  double x = eval_expr(p, e->param[1]);
217  int id = e->param[2] ? av_clip(eval_expr(p, e->param[2]), 0, VARS-1) : 0;
218  int i;
219  double var0 = p->var[id];
220  for(i=0; i<1000; i++) {
221  double ld = d;
222  p->var[id] = i;
223  v = eval_expr(p, e->param[0]);
224  d += t*v;
225  if(ld==d && v)
226  break;
227  t *= x / (i+1);
228  }
229  p->var[id] = var0;
230  return d;
231  }
232  case e_root: {
233  int i, j;
234  double low = -1, high = -1, v, low_v = -DBL_MAX, high_v = DBL_MAX;
235  double var0 = p->var[0];
236  double x_max = eval_expr(p, e->param[1]);
237  for(i=-1; i<1024; i++) {
238  if(i<255) {
239  p->var[0] = av_reverse[i&255]*x_max/255;
240  } else {
241  p->var[0] = x_max*pow(0.9, i-255);
242  if (i&1) p->var[0] *= -1;
243  if (i&2) p->var[0] += low;
244  else p->var[0] += high;
245  }
246  v = eval_expr(p, e->param[0]);
247  if (v<=0 && v>low_v) {
248  low = p->var[0];
249  low_v = v;
250  }
251  if (v>=0 && v<high_v) {
252  high = p->var[0];
253  high_v = v;
254  }
255  if (low>=0 && high>=0){
256  for (j=0; j<1000; j++) {
257  p->var[0] = (low+high)*0.5;
258  if (low == p->var[0] || high == p->var[0])
259  break;
260  v = eval_expr(p, e->param[0]);
261  if (v<=0) low = p->var[0];
262  if (v>=0) high= p->var[0];
263  if (isnan(v)) {
264  low = high = v;
265  break;
266  }
267  }
268  break;
269  }
270  }
271  p->var[0] = var0;
272  return -low_v<high_v ? low : high;
273  }
274  default: {
275  double d = eval_expr(p, e->param[0]);
276  double d2 = eval_expr(p, e->param[1]);
277  switch (e->type) {
278  case e_mod: return e->value * (d - floor((!CONFIG_FTRAPV || d2) ? d / d2 : d * INFINITY) * d2);
279  case e_gcd: return e->value * av_gcd(d,d2);
280  case e_max: return e->value * (d > d2 ? d : d2);
281  case e_min: return e->value * (d < d2 ? d : d2);
282  case e_eq: return e->value * (d == d2 ? 1.0 : 0.0);
283  case e_gt: return e->value * (d > d2 ? 1.0 : 0.0);
284  case e_gte: return e->value * (d >= d2 ? 1.0 : 0.0);
285  case e_lt: return e->value * (d < d2 ? 1.0 : 0.0);
286  case e_lte: return e->value * (d <= d2 ? 1.0 : 0.0);
287  case e_pow: return e->value * pow(d, d2);
288  case e_mul: return e->value * (d * d2);
289  case e_div: return e->value * ((!CONFIG_FTRAPV || d2 ) ? (d / d2) : d * INFINITY);
290  case e_add: return e->value * (d + d2);
291  case e_last:return e->value * d2;
292  case e_st : return e->value * (p->var[av_clip(d, 0, VARS-1)]= d2);
293  case e_hypot:return e->value * (sqrt(d*d + d2*d2));
294  case e_bitand: return isnan(d) || isnan(d2) ? NAN : e->value * ((long int)d & (long int)d2);
295  case e_bitor: return isnan(d) || isnan(d2) ? NAN : e->value * ((long int)d | (long int)d2);
296  }
297  }
298  }
299  return NAN;
300 }
301 
302 static int parse_expr(AVExpr **e, Parser *p);
303 
304 void av_expr_free(AVExpr *e)
305 {
306  if (!e) return;
307  av_expr_free(e->param[0]);
308  av_expr_free(e->param[1]);
309  av_expr_free(e->param[2]);
310  av_freep(&e->var);
311  av_freep(&e);
312 }
313 
314 static int parse_primary(AVExpr **e, Parser *p)
315 {
316  AVExpr *d = av_mallocz(sizeof(AVExpr));
317  char *next = p->s, *s0 = p->s;
318  int ret, i;
319 
320  if (!d)
321  return AVERROR(ENOMEM);
322 
323  /* number */
324  d->value = av_strtod(p->s, &next);
325  if (next != p->s) {
326  d->type = e_value;
327  p->s= next;
328  *e = d;
329  return 0;
330  }
331  d->value = 1;
332 
333  /* named constants */
334  for (i=0; p->const_names && p->const_names[i]; i++) {
335  if (strmatch(p->s, p->const_names[i])) {
336  p->s+= strlen(p->const_names[i]);
337  d->type = e_const;
338  d->a.const_index = i;
339  *e = d;
340  return 0;
341  }
342  }
343  for (i = 0; i < FF_ARRAY_ELEMS(constants); i++) {
344  if (strmatch(p->s, constants[i].name)) {
345  p->s += strlen(constants[i].name);
346  d->type = e_value;
347  d->value = constants[i].value;
348  *e = d;
349  return 0;
350  }
351  }
352 
353  p->s= strchr(p->s, '(');
354  if (p->s==NULL) {
355  av_log(p, AV_LOG_ERROR, "Undefined constant or missing '(' in '%s'\n", s0);
356  p->s= next;
357  av_expr_free(d);
358  return AVERROR(EINVAL);
359  }
360  p->s++; // "("
361  if (*next == '(') { // special case do-nothing
362  av_freep(&d);
363  if ((ret = parse_expr(&d, p)) < 0)
364  return ret;
365  if (p->s[0] != ')') {
366  av_log(p, AV_LOG_ERROR, "Missing ')' in '%s'\n", s0);
367  av_expr_free(d);
368  return AVERROR(EINVAL);
369  }
370  p->s++; // ")"
371  *e = d;
372  return 0;
373  }
374  if ((ret = parse_expr(&(d->param[0]), p)) < 0) {
375  av_expr_free(d);
376  return ret;
377  }
378  if (p->s[0]== ',') {
379  p->s++; // ","
380  parse_expr(&d->param[1], p);
381  }
382  if (p->s[0]== ',') {
383  p->s++; // ","
384  parse_expr(&d->param[2], p);
385  }
386  if (p->s[0] != ')') {
387  av_log(p, AV_LOG_ERROR, "Missing ')' or too many args in '%s'\n", s0);
388  av_expr_free(d);
389  return AVERROR(EINVAL);
390  }
391  p->s++; // ")"
392 
393  d->type = e_func0;
394  if (strmatch(next, "sinh" )) d->a.func0 = sinh;
395  else if (strmatch(next, "cosh" )) d->a.func0 = cosh;
396  else if (strmatch(next, "tanh" )) d->a.func0 = tanh;
397  else if (strmatch(next, "sin" )) d->a.func0 = sin;
398  else if (strmatch(next, "cos" )) d->a.func0 = cos;
399  else if (strmatch(next, "tan" )) d->a.func0 = tan;
400  else if (strmatch(next, "atan" )) d->a.func0 = atan;
401  else if (strmatch(next, "asin" )) d->a.func0 = asin;
402  else if (strmatch(next, "acos" )) d->a.func0 = acos;
403  else if (strmatch(next, "exp" )) d->a.func0 = exp;
404  else if (strmatch(next, "log" )) d->a.func0 = log;
405  else if (strmatch(next, "abs" )) d->a.func0 = fabs;
406  else if (strmatch(next, "time" )) d->a.func0 = etime;
407  else if (strmatch(next, "squish")) d->type = e_squish;
408  else if (strmatch(next, "gauss" )) d->type = e_gauss;
409  else if (strmatch(next, "mod" )) d->type = e_mod;
410  else if (strmatch(next, "max" )) d->type = e_max;
411  else if (strmatch(next, "min" )) d->type = e_min;
412  else if (strmatch(next, "eq" )) d->type = e_eq;
413  else if (strmatch(next, "gte" )) d->type = e_gte;
414  else if (strmatch(next, "gt" )) d->type = e_gt;
415  else if (strmatch(next, "lte" )) d->type = e_lte;
416  else if (strmatch(next, "lt" )) d->type = e_lt;
417  else if (strmatch(next, "ld" )) d->type = e_ld;
418  else if (strmatch(next, "isnan" )) d->type = e_isnan;
419  else if (strmatch(next, "isinf" )) d->type = e_isinf;
420  else if (strmatch(next, "st" )) d->type = e_st;
421  else if (strmatch(next, "while" )) d->type = e_while;
422  else if (strmatch(next, "taylor")) d->type = e_taylor;
423  else if (strmatch(next, "root" )) d->type = e_root;
424  else if (strmatch(next, "floor" )) d->type = e_floor;
425  else if (strmatch(next, "ceil" )) d->type = e_ceil;
426  else if (strmatch(next, "trunc" )) d->type = e_trunc;
427  else if (strmatch(next, "sqrt" )) d->type = e_sqrt;
428  else if (strmatch(next, "not" )) d->type = e_not;
429  else if (strmatch(next, "pow" )) d->type = e_pow;
430  else if (strmatch(next, "print" )) d->type = e_print;
431  else if (strmatch(next, "random")) d->type = e_random;
432  else if (strmatch(next, "hypot" )) d->type = e_hypot;
433  else if (strmatch(next, "gcd" )) d->type = e_gcd;
434  else if (strmatch(next, "if" )) d->type = e_if;
435  else if (strmatch(next, "ifnot" )) d->type = e_ifnot;
436  else if (strmatch(next, "bitand")) d->type = e_bitand;
437  else if (strmatch(next, "bitor" )) d->type = e_bitor;
438  else if (strmatch(next, "between"))d->type = e_between;
439  else {
440  for (i=0; p->func1_names && p->func1_names[i]; i++) {
441  if (strmatch(next, p->func1_names[i])) {
442  d->a.func1 = p->funcs1[i];
443  d->type = e_func1;
444  *e = d;
445  return 0;
446  }
447  }
448 
449  for (i=0; p->func2_names && p->func2_names[i]; i++) {
450  if (strmatch(next, p->func2_names[i])) {
451  d->a.func2 = p->funcs2[i];
452  d->type = e_func2;
453  *e = d;
454  return 0;
455  }
456  }
457 
458  av_log(p, AV_LOG_ERROR, "Unknown function in '%s'\n", s0);
459  av_expr_free(d);
460  return AVERROR(EINVAL);
461  }
462 
463  *e = d;
464  return 0;
465 }
466 
467 static AVExpr *make_eval_expr(int type, int value, AVExpr *p0, AVExpr *p1)
468 {
469  AVExpr *e = av_mallocz(sizeof(AVExpr));
470  if (!e)
471  return NULL;
472  e->type =type ;
473  e->value =value ;
474  e->param[0] =p0 ;
475  e->param[1] =p1 ;
476  return e;
477 }
478 
479 static int parse_pow(AVExpr **e, Parser *p, int *sign)
480 {
481  *sign= (*p->s == '+') - (*p->s == '-');
482  p->s += *sign&1;
483  return parse_primary(e, p);
484 }
485 
486 static int parse_dB(AVExpr **e, Parser *p, int *sign)
487 {
488  /* do not filter out the negative sign when parsing a dB value.
489  for example, -3dB is not the same as -(3dB) */
490  if (*p->s == '-') {
491  char *next;
492  double av_unused ignored = strtod(p->s, &next);
493  if (next != p->s && next[0] == 'd' && next[1] == 'B') {
494  *sign = 0;
495  return parse_primary(e, p);
496  }
497  }
498  return parse_pow(e, p, sign);
499 }
500 
501 static int parse_factor(AVExpr **e, Parser *p)
502 {
503  int sign, sign2, ret;
504  AVExpr *e0, *e1, *e2;
505  if ((ret = parse_dB(&e0, p, &sign)) < 0)
506  return ret;
507  while(p->s[0]=='^'){
508  e1 = e0;
509  p->s++;
510  if ((ret = parse_dB(&e2, p, &sign2)) < 0) {
511  av_expr_free(e1);
512  return ret;
513  }
514  e0 = make_eval_expr(e_pow, 1, e1, e2);
515  if (!e0) {
516  av_expr_free(e1);
517  av_expr_free(e2);
518  return AVERROR(ENOMEM);
519  }
520  if (e0->param[1]) e0->param[1]->value *= (sign2|1);
521  }
522  if (e0) e0->value *= (sign|1);
523 
524  *e = e0;
525  return 0;
526 }
527 
528 static int parse_term(AVExpr **e, Parser *p)
529 {
530  int ret;
531  AVExpr *e0, *e1, *e2;
532  if ((ret = parse_factor(&e0, p)) < 0)
533  return ret;
534  while (p->s[0]=='*' || p->s[0]=='/') {
535  int c= *p->s++;
536  e1 = e0;
537  if ((ret = parse_factor(&e2, p)) < 0) {
538  av_expr_free(e1);
539  return ret;
540  }
541  e0 = make_eval_expr(c == '*' ? e_mul : e_div, 1, e1, e2);
542  if (!e0) {
543  av_expr_free(e1);
544  av_expr_free(e2);
545  return AVERROR(ENOMEM);
546  }
547  }
548  *e = e0;
549  return 0;
550 }
551 
552 static int parse_subexpr(AVExpr **e, Parser *p)
553 {
554  int ret;
555  AVExpr *e0, *e1, *e2;
556  if ((ret = parse_term(&e0, p)) < 0)
557  return ret;
558  while (*p->s == '+' || *p->s == '-') {
559  e1 = e0;
560  if ((ret = parse_term(&e2, p)) < 0) {
561  av_expr_free(e1);
562  return ret;
563  }
564  e0 = make_eval_expr(e_add, 1, e1, e2);
565  if (!e0) {
566  av_expr_free(e1);
567  av_expr_free(e2);
568  return AVERROR(ENOMEM);
569  }
570  };
571 
572  *e = e0;
573  return 0;
574 }
575 
576 static int parse_expr(AVExpr **e, Parser *p)
577 {
578  int ret;
579  AVExpr *e0, *e1, *e2;
580  if (p->stack_index <= 0) //protect against stack overflows
581  return AVERROR(EINVAL);
582  p->stack_index--;
583 
584  if ((ret = parse_subexpr(&e0, p)) < 0)
585  return ret;
586  while (*p->s == ';') {
587  p->s++;
588  e1 = e0;
589  if ((ret = parse_subexpr(&e2, p)) < 0) {
590  av_expr_free(e1);
591  return ret;
592  }
593  e0 = make_eval_expr(e_last, 1, e1, e2);
594  if (!e0) {
595  av_expr_free(e1);
596  av_expr_free(e2);
597  return AVERROR(ENOMEM);
598  }
599  };
600 
601  p->stack_index++;
602  *e = e0;
603  return 0;
604 }
605 
606 static int verify_expr(AVExpr *e)
607 {
608  if (!e) return 0;
609  switch (e->type) {
610  case e_value:
611  case e_const: return 1;
612  case e_func0:
613  case e_func1:
614  case e_squish:
615  case e_ld:
616  case e_gauss:
617  case e_isnan:
618  case e_isinf:
619  case e_floor:
620  case e_ceil:
621  case e_trunc:
622  case e_sqrt:
623  case e_not:
624  case e_random:
625  return verify_expr(e->param[0]) && !e->param[1];
626  case e_print:
627  return verify_expr(e->param[0])
628  && (!e->param[1] || verify_expr(e->param[1]));
629  case e_if:
630  case e_ifnot:
631  case e_taylor:
632  return verify_expr(e->param[0]) && verify_expr(e->param[1])
633  && (!e->param[2] || verify_expr(e->param[2]));
634  case e_between:
635  return verify_expr(e->param[0]) &&
636  verify_expr(e->param[1]) &&
637  verify_expr(e->param[2]);
638  default: return verify_expr(e->param[0]) && verify_expr(e->param[1]) && !e->param[2];
639  }
640 }
641 
642 int av_expr_parse(AVExpr **expr, const char *s,
643  const char * const *const_names,
644  const char * const *func1_names, double (* const *funcs1)(void *, double),
645  const char * const *func2_names, double (* const *funcs2)(void *, double, double),
646  int log_offset, void *log_ctx)
647 {
648  Parser p = { 0 };
649  AVExpr *e = NULL;
650  char *w = av_malloc(strlen(s) + 1);
651  char *wp = w;
652  const char *s0 = s;
653  int ret = 0;
654 
655  if (!w)
656  return AVERROR(ENOMEM);
657 
658  while (*s)
659  if (!av_isspace(*s++)) *wp++ = s[-1];
660  *wp++ = 0;
661 
662  p.class = &eval_class;
663  p.stack_index=100;
664  p.s= w;
665  p.const_names = const_names;
666  p.funcs1 = funcs1;
667  p.func1_names = func1_names;
668  p.funcs2 = funcs2;
669  p.func2_names = func2_names;
670  p.log_offset = log_offset;
671  p.log_ctx = log_ctx;
672 
673  if ((ret = parse_expr(&e, &p)) < 0)
674  goto end;
675  if (*p.s) {
676  av_expr_free(e);
677  av_log(&p, AV_LOG_ERROR, "Invalid chars '%s' at the end of expression '%s'\n", p.s, s0);
678  ret = AVERROR(EINVAL);
679  goto end;
680  }
681  if (!verify_expr(e)) {
682  av_expr_free(e);
683  ret = AVERROR(EINVAL);
684  goto end;
685  }
686  e->var= av_mallocz(sizeof(double) *VARS);
687  *expr = e;
688 end:
689  av_free(w);
690  return ret;
691 }
692 
693 double av_expr_eval(AVExpr *e, const double *const_values, void *opaque)
694 {
695  Parser p = { 0 };
696  p.var= e->var;
697 
698  p.const_values = const_values;
699  p.opaque = opaque;
700  return eval_expr(&p, e);
701 }
702 
703 int av_expr_parse_and_eval(double *d, const char *s,
704  const char * const *const_names, const double *const_values,
705  const char * const *func1_names, double (* const *funcs1)(void *, double),
706  const char * const *func2_names, double (* const *funcs2)(void *, double, double),
707  void *opaque, int log_offset, void *log_ctx)
708 {
709  AVExpr *e = NULL;
710  int ret = av_expr_parse(&e, s, const_names, func1_names, funcs1, func2_names, funcs2, log_offset, log_ctx);
711 
712  if (ret < 0) {
713  *d = NAN;
714  return ret;
715  }
716  *d = av_expr_eval(e, const_values, opaque);
717  av_expr_free(e);
718  return isnan(*d) ? AVERROR(EINVAL) : 0;
719 }
720 
721 #ifdef TEST
722 #include <string.h>
723 
724 static const double const_values[] = {
725  M_PI,
726  M_E,
727  0
728 };
729 
730 static const char *const const_names[] = {
731  "PI",
732  "E",
733  0
734 };
735 
736 int main(int argc, char **argv)
737 {
738  int i;
739  double d;
740  const char *const *expr;
741  static const char *const exprs[] = {
742  "",
743  "1;2",
744  "-20",
745  "-PI",
746  "+PI",
747  "1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)",
748  "80G/80Gi",
749  "1k",
750  "1Gi",
751  "1gi",
752  "1GiFoo",
753  "1k+1k",
754  "1Gi*3foo",
755  "foo",
756  "foo(",
757  "foo()",
758  "foo)",
759  "sin",
760  "sin(",
761  "sin()",
762  "sin)",
763  "sin 10",
764  "sin(1,2,3)",
765  "sin(1 )",
766  "1",
767  "1foo",
768  "bar + PI + E + 100f*2 + foo",
769  "13k + 12f - foo(1, 2)",
770  "1gi",
771  "1Gi",
772  "st(0, 123)",
773  "st(1, 123); ld(1)",
774  "lte(0, 1)",
775  "lte(1, 1)",
776  "lte(1, 0)",
777  "lt(0, 1)",
778  "lt(1, 1)",
779  "gt(1, 0)",
780  "gt(2, 7)",
781  "gte(122, 122)",
782  /* compute 1+2+...+N */
783  "st(0, 1); while(lte(ld(0), 100), st(1, ld(1)+ld(0));st(0, ld(0)+1)); ld(1)",
784  /* compute Fib(N) */
785  "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)",
786  "while(0, 10)",
787  "st(0, 1); while(lte(ld(0),100), st(1, ld(1)+ld(0)); st(0, ld(0)+1))",
788  "isnan(1)",
789  "isnan(NAN)",
790  "isnan(INF)",
791  "isinf(1)",
792  "isinf(NAN)",
793  "isinf(INF)",
794  "floor(NAN)",
795  "floor(123.123)",
796  "floor(-123.123)",
797  "trunc(123.123)",
798  "trunc(-123.123)",
799  "ceil(123.123)",
800  "ceil(-123.123)",
801  "sqrt(1764)",
802  "isnan(sqrt(-1))",
803  "not(1)",
804  "not(NAN)",
805  "not(0)",
806  "6.0206dB",
807  "-3.0103dB",
808  "pow(0,1.23)",
809  "pow(PI,1.23)",
810  "PI^1.23",
811  "pow(-1,1.23)",
812  "if(1, 2)",
813  "if(1, 1, 2)",
814  "if(0, 1, 2)",
815  "ifnot(0, 23)",
816  "ifnot(1, NaN) + if(0, 1)",
817  "ifnot(1, 1, 2)",
818  "ifnot(0, 1, 2)",
819  "taylor(1, 1)",
820  "taylor(eq(mod(ld(1),4),1)-eq(mod(ld(1),4),3), PI/2, 1)",
821  "root(sin(ld(0))-1, 2)",
822  "root(sin(ld(0))+6+sin(ld(0)/12)-log(ld(0)), 100)",
823  "7000000B*random(0)",
824  "squish(2)",
825  "gauss(0.1)",
826  "hypot(4,3)",
827  "gcd(30,55)*print(min(9,1))",
828  "bitor(42, 12)",
829  "bitand(42, 12)",
830  "bitand(NAN, 1)",
831  "between(10, -3, 10)",
832  "between(-4, -2, -1)",
833  "between(1,2)",
834  NULL
835  };
836 
837  for (expr = exprs; *expr; expr++) {
838  printf("Evaluating '%s'\n", *expr);
839  av_expr_parse_and_eval(&d, *expr,
840  const_names, const_values,
841  NULL, NULL, NULL, NULL, NULL, 0, NULL);
842  if (isnan(d))
843  printf("'%s' -> nan\n\n", *expr);
844  else
845  printf("'%s' -> %f\n\n", *expr, d);
846  }
847 
848  av_expr_parse_and_eval(&d, "1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)",
849  const_names, const_values,
850  NULL, NULL, NULL, NULL, NULL, 0, NULL);
851  printf("%f == 12.7\n", d);
852  av_expr_parse_and_eval(&d, "80G/80Gi",
853  const_names, const_values,
854  NULL, NULL, NULL, NULL, NULL, 0, NULL);
855  printf("%f == 0.931322575\n", d);
856 
857  if (argc > 1 && !strcmp(argv[1], "-t")) {
858  for (i = 0; i < 1050; i++) {
859  START_TIMER;
860  av_expr_parse_and_eval(&d, "1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)",
861  const_names, const_values,
862  NULL, NULL, NULL, NULL, NULL, 0, NULL);
863  STOP_TIMER("av_expr_parse_and_eval");
864  }
865  }
866 
867  return 0;
868 }
869 #endif
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