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