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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 
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;
55 
56 static const AVClass eval_class = { "Eval", av_default_item_name, NULL, LIBAVUTIL_VERSION_INT, offsetof(Parser,log_offset), offsetof(Parser,log_ctx) };
57 
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 };
80 
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 };
89 
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
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