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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 "internal.h"
35 #include "log.h"
36 #include "mathematics.h"
37 #include "time.h"
38 #include "avstring.h"
39 #include "timer.h"
40 
41 typedef struct Parser {
42  const AVClass *class;
44  char *s;
45  const double *const_values;
46  const char * const *const_names; // NULL terminated
47  double (* const *funcs1)(void *, double a); // NULL terminated
48  const char * const *func1_names; // NULL terminated
49  double (* const *funcs2)(void *, double a, double b); // NULL terminated
50  const char * const *func2_names; // NULL terminated
51  void *opaque;
53  void *log_ctx;
54 #define VARS 10
55  double *var;
56 } Parser;
57 
58 static const AVClass eval_class = { "Eval", av_default_item_name, NULL, LIBAVUTIL_VERSION_INT, offsetof(Parser,log_offset), offsetof(Parser,log_ctx) };
59 
60 static const struct {
61  double bin_val;
62  double dec_val;
63  int8_t exp;
64 } si_prefixes['z' - 'E' + 1] = {
65  ['y'-'E']= { 8.271806125530276749e-25, 1e-24, -24 },
66  ['z'-'E']= { 8.4703294725430034e-22, 1e-21, -21 },
67  ['a'-'E']= { 8.6736173798840355e-19, 1e-18, -18 },
68  ['f'-'E']= { 8.8817841970012523e-16, 1e-15, -15 },
69  ['p'-'E']= { 9.0949470177292824e-13, 1e-12, -12 },
70  ['n'-'E']= { 9.3132257461547852e-10, 1e-9, -9 },
71  ['u'-'E']= { 9.5367431640625e-7, 1e-6, -6 },
72  ['m'-'E']= { 9.765625e-4, 1e-3, -3 },
73  ['c'-'E']= { 9.8431332023036951e-3, 1e-2, -2 },
74  ['d'-'E']= { 9.921256574801246e-2, 1e-1, -1 },
75  ['h'-'E']= { 1.0159366732596479e2, 1e2, 2 },
76  ['k'-'E']= { 1.024e3, 1e3, 3 },
77  ['K'-'E']= { 1.024e3, 1e3, 3 },
78  ['M'-'E']= { 1.048576e6, 1e6, 6 },
79  ['G'-'E']= { 1.073741824e9, 1e9, 9 },
80  ['T'-'E']= { 1.099511627776e12, 1e12, 12 },
81  ['P'-'E']= { 1.125899906842624e15, 1e15, 15 },
82  ['E'-'E']= { 1.152921504606847e18, 1e18, 18 },
83  ['Z'-'E']= { 1.1805916207174113e21, 1e21, 21 },
84  ['Y'-'E']= { 1.2089258196146292e24, 1e24, 24 },
85 };
86 
87 static const struct {
88  const char *name;
89  double value;
90 } constants[] = {
91  { "E", M_E },
92  { "PI", M_PI },
93  { "PHI", M_PHI },
94  { "QP2LAMBDA", FF_QP2LAMBDA },
95 };
96 
97 double av_strtod(const char *numstr, char **tail)
98 {
99  double d;
100  char *next;
101  if(numstr[0]=='0' && (numstr[1]|0x20)=='x') {
102  d = strtoul(numstr, &next, 16);
103  } else
104  d = strtod(numstr, &next);
105  /* if parsing succeeded, check for and interpret postfixes */
106  if (next!=numstr) {
107  if (next[0] == 'd' && next[1] == 'B') {
108  /* treat dB as decibels instead of decibytes */
109  d = ff_exp10(d / 20);
110  next += 2;
111  } else if (*next >= 'E' && *next <= 'z') {
112  int e= si_prefixes[*next - 'E'].exp;
113  if (e) {
114  if (next[1] == 'i') {
115  d*= si_prefixes[*next - 'E'].bin_val;
116  next+=2;
117  } else {
118  d*= si_prefixes[*next - 'E'].dec_val;
119  next++;
120  }
121  }
122  }
123 
124  if (*next=='B') {
125  d*=8;
126  next++;
127  }
128  }
129  /* if requested, fill in tail with the position after the last parsed
130  character */
131  if (tail)
132  *tail = next;
133  return d;
134 }
135 
136 #define IS_IDENTIFIER_CHAR(c) ((c) - '0' <= 9U || (c) - 'a' <= 25U || (c) - 'A' <= 25U || (c) == '_')
137 
138 static int strmatch(const char *s, const char *prefix)
139 {
140  int i;
141  for (i=0; prefix[i]; i++) {
142  if (prefix[i] != s[i]) return 0;
143  }
144  /* return 1 only if the s identifier is terminated */
145  return !IS_IDENTIFIER_CHAR(s[i]);
146 }
147 
148 struct AVExpr {
149  enum {
157  } type;
158  double value; // is sign in other types
159  union {
161  double (*func0)(double);
162  double (*func1)(void *, double);
163  double (*func2)(void *, double, double);
164  } a;
165  struct AVExpr *param[3];
166  double *var;
167 };
168 
169 static double etime(double v)
170 {
171  return av_gettime() * 0.000001;
172 }
173 
174 static double eval_expr(Parser *p, AVExpr *e)
175 {
176  switch (e->type) {
177  case e_value: return e->value;
178  case e_const: return e->value * p->const_values[e->a.const_index];
179  case e_func0: return e->value * e->a.func0(eval_expr(p, e->param[0]));
180  case e_func1: return e->value * e->a.func1(p->opaque, eval_expr(p, e->param[0]));
181  case e_func2: return e->value * e->a.func2(p->opaque, eval_expr(p, e->param[0]), eval_expr(p, e->param[1]));
182  case e_squish: return 1/(1+exp(4*eval_expr(p, e->param[0])));
183  case e_gauss: { double d = eval_expr(p, e->param[0]); return exp(-d*d/2)/sqrt(2*M_PI); }
184  case e_ld: return e->value * p->var[av_clip(eval_expr(p, e->param[0]), 0, VARS-1)];
185  case e_isnan: return e->value * !!isnan(eval_expr(p, e->param[0]));
186  case e_isinf: return e->value * !!isinf(eval_expr(p, e->param[0]));
187  case e_floor: return e->value * floor(eval_expr(p, e->param[0]));
188  case e_ceil : return e->value * ceil (eval_expr(p, e->param[0]));
189  case e_trunc: return e->value * trunc(eval_expr(p, e->param[0]));
190  case e_sqrt: return e->value * sqrt (eval_expr(p, e->param[0]));
191  case e_not: return e->value * (eval_expr(p, e->param[0]) == 0);
192  case e_if: return e->value * (eval_expr(p, e->param[0]) ? eval_expr(p, e->param[1]) :
193  e->param[2] ? eval_expr(p, e->param[2]) : 0);
194  case e_ifnot: return e->value * (!eval_expr(p, e->param[0]) ? eval_expr(p, e->param[1]) :
195  e->param[2] ? eval_expr(p, e->param[2]) : 0);
196  case e_clip: {
197  double x = eval_expr(p, e->param[0]);
198  double min = eval_expr(p, e->param[1]), max = eval_expr(p, e->param[2]);
199  if (isnan(min) || isnan(max) || isnan(x) || min > max)
200  return NAN;
201  return e->value * av_clipd(eval_expr(p, e->param[0]), min, max);
202  }
203  case e_between: {
204  double d = eval_expr(p, e->param[0]);
205  return e->value * (d >= eval_expr(p, e->param[1]) &&
206  d <= eval_expr(p, e->param[2]));
207  }
208  case e_print: {
209  double x = eval_expr(p, e->param[0]);
210  int level = e->param[1] ? av_clip(eval_expr(p, e->param[1]), INT_MIN, INT_MAX) : AV_LOG_INFO;
211  av_log(p, level, "%f\n", x);
212  return x;
213  }
214  case e_random:{
215  int idx= av_clip(eval_expr(p, e->param[0]), 0, VARS-1);
216  uint64_t r= isnan(p->var[idx]) ? 0 : p->var[idx];
217  r= r*1664525+1013904223;
218  p->var[idx]= r;
219  return e->value * (r * (1.0/UINT64_MAX));
220  }
221  case e_while: {
222  double d = NAN;
223  while (eval_expr(p, e->param[0]))
224  d=eval_expr(p, e->param[1]);
225  return d;
226  }
227  case e_taylor: {
228  double t = 1, d = 0, v;
229  double x = eval_expr(p, e->param[1]);
230  int id = e->param[2] ? av_clip(eval_expr(p, e->param[2]), 0, VARS-1) : 0;
231  int i;
232  double var0 = p->var[id];
233  for(i=0; i<1000; i++) {
234  double ld = d;
235  p->var[id] = i;
236  v = eval_expr(p, e->param[0]);
237  d += t*v;
238  if(ld==d && v)
239  break;
240  t *= x / (i+1);
241  }
242  p->var[id] = var0;
243  return d;
244  }
245  case e_root: {
246  int i, j;
247  double low = -1, high = -1, v, low_v = -DBL_MAX, high_v = DBL_MAX;
248  double var0 = p->var[0];
249  double x_max = eval_expr(p, e->param[1]);
250  for(i=-1; i<1024; i++) {
251  if(i<255) {
252  p->var[0] = ff_reverse[i&255]*x_max/255;
253  } else {
254  p->var[0] = x_max*pow(0.9, i-255);
255  if (i&1) p->var[0] *= -1;
256  if (i&2) p->var[0] += low;
257  else p->var[0] += high;
258  }
259  v = eval_expr(p, e->param[0]);
260  if (v<=0 && v>low_v) {
261  low = p->var[0];
262  low_v = v;
263  }
264  if (v>=0 && v<high_v) {
265  high = p->var[0];
266  high_v = v;
267  }
268  if (low>=0 && high>=0){
269  for (j=0; j<1000; j++) {
270  p->var[0] = (low+high)*0.5;
271  if (low == p->var[0] || high == p->var[0])
272  break;
273  v = eval_expr(p, e->param[0]);
274  if (v<=0) low = p->var[0];
275  if (v>=0) high= p->var[0];
276  if (isnan(v)) {
277  low = high = v;
278  break;
279  }
280  }
281  break;
282  }
283  }
284  p->var[0] = var0;
285  return -low_v<high_v ? low : high;
286  }
287  default: {
288  double d = eval_expr(p, e->param[0]);
289  double d2 = eval_expr(p, e->param[1]);
290  switch (e->type) {
291  case e_mod: return e->value * (d - floor((!CONFIG_FTRAPV || d2) ? d / d2 : d * INFINITY) * d2);
292  case e_gcd: return e->value * av_gcd(d,d2);
293  case e_max: return e->value * (d > d2 ? d : d2);
294  case e_min: return e->value * (d < d2 ? d : d2);
295  case e_eq: return e->value * (d == d2 ? 1.0 : 0.0);
296  case e_gt: return e->value * (d > d2 ? 1.0 : 0.0);
297  case e_gte: return e->value * (d >= d2 ? 1.0 : 0.0);
298  case e_lt: return e->value * (d < d2 ? 1.0 : 0.0);
299  case e_lte: return e->value * (d <= d2 ? 1.0 : 0.0);
300  case e_pow: return e->value * pow(d, d2);
301  case e_mul: return e->value * (d * d2);
302  case e_div: return e->value * ((!CONFIG_FTRAPV || d2 ) ? (d / d2) : d * INFINITY);
303  case e_add: return e->value * (d + d2);
304  case e_last:return e->value * d2;
305  case e_st : return e->value * (p->var[av_clip(d, 0, VARS-1)]= d2);
306  case e_hypot:return e->value * hypot(d, d2);
307  case e_bitand: return isnan(d) || isnan(d2) ? NAN : e->value * ((long int)d & (long int)d2);
308  case e_bitor: return isnan(d) || isnan(d2) ? NAN : e->value * ((long int)d | (long int)d2);
309  }
310  }
311  }
312  return NAN;
313 }
314 
315 static int parse_expr(AVExpr **e, Parser *p);
316 
318 {
319  if (!e) return;
320  av_expr_free(e->param[0]);
321  av_expr_free(e->param[1]);
322  av_expr_free(e->param[2]);
323  av_freep(&e->var);
324  av_freep(&e);
325 }
326 
327 static int parse_primary(AVExpr **e, Parser *p)
328 {
329  AVExpr *d = av_mallocz(sizeof(AVExpr));
330  char *next = p->s, *s0 = p->s;
331  int ret, i;
332 
333  if (!d)
334  return AVERROR(ENOMEM);
335 
336  /* number */
337  d->value = av_strtod(p->s, &next);
338  if (next != p->s) {
339  d->type = e_value;
340  p->s= next;
341  *e = d;
342  return 0;
343  }
344  d->value = 1;
345 
346  /* named constants */
347  for (i=0; p->const_names && p->const_names[i]; i++) {
348  if (strmatch(p->s, p->const_names[i])) {
349  p->s+= strlen(p->const_names[i]);
350  d->type = e_const;
351  d->a.const_index = i;
352  *e = d;
353  return 0;
354  }
355  }
356  for (i = 0; i < FF_ARRAY_ELEMS(constants); i++) {
357  if (strmatch(p->s, constants[i].name)) {
358  p->s += strlen(constants[i].name);
359  d->type = e_value;
360  d->value = constants[i].value;
361  *e = d;
362  return 0;
363  }
364  }
365 
366  p->s= strchr(p->s, '(');
367  if (!p->s) {
368  av_log(p, AV_LOG_ERROR, "Undefined constant or missing '(' in '%s'\n", s0);
369  p->s= next;
370  av_expr_free(d);
371  return AVERROR(EINVAL);
372  }
373  p->s++; // "("
374  if (*next == '(') { // special case do-nothing
375  av_freep(&d);
376  if ((ret = parse_expr(&d, p)) < 0)
377  return ret;
378  if (p->s[0] != ')') {
379  av_log(p, AV_LOG_ERROR, "Missing ')' in '%s'\n", s0);
380  av_expr_free(d);
381  return AVERROR(EINVAL);
382  }
383  p->s++; // ")"
384  *e = d;
385  return 0;
386  }
387  if ((ret = parse_expr(&(d->param[0]), p)) < 0) {
388  av_expr_free(d);
389  return ret;
390  }
391  if (p->s[0]== ',') {
392  p->s++; // ","
393  parse_expr(&d->param[1], p);
394  }
395  if (p->s[0]== ',') {
396  p->s++; // ","
397  parse_expr(&d->param[2], p);
398  }
399  if (p->s[0] != ')') {
400  av_log(p, AV_LOG_ERROR, "Missing ')' or too many args in '%s'\n", s0);
401  av_expr_free(d);
402  return AVERROR(EINVAL);
403  }
404  p->s++; // ")"
405 
406  d->type = e_func0;
407  if (strmatch(next, "sinh" )) d->a.func0 = sinh;
408  else if (strmatch(next, "cosh" )) d->a.func0 = cosh;
409  else if (strmatch(next, "tanh" )) d->a.func0 = tanh;
410  else if (strmatch(next, "sin" )) d->a.func0 = sin;
411  else if (strmatch(next, "cos" )) d->a.func0 = cos;
412  else if (strmatch(next, "tan" )) d->a.func0 = tan;
413  else if (strmatch(next, "atan" )) d->a.func0 = atan;
414  else if (strmatch(next, "asin" )) d->a.func0 = asin;
415  else if (strmatch(next, "acos" )) d->a.func0 = acos;
416  else if (strmatch(next, "exp" )) d->a.func0 = exp;
417  else if (strmatch(next, "log" )) d->a.func0 = log;
418  else if (strmatch(next, "abs" )) d->a.func0 = fabs;
419  else if (strmatch(next, "time" )) d->a.func0 = etime;
420  else if (strmatch(next, "squish")) d->type = e_squish;
421  else if (strmatch(next, "gauss" )) d->type = e_gauss;
422  else if (strmatch(next, "mod" )) d->type = e_mod;
423  else if (strmatch(next, "max" )) d->type = e_max;
424  else if (strmatch(next, "min" )) d->type = e_min;
425  else if (strmatch(next, "eq" )) d->type = e_eq;
426  else if (strmatch(next, "gte" )) d->type = e_gte;
427  else if (strmatch(next, "gt" )) d->type = e_gt;
428  else if (strmatch(next, "lte" )) d->type = e_lte;
429  else if (strmatch(next, "lt" )) d->type = e_lt;
430  else if (strmatch(next, "ld" )) d->type = e_ld;
431  else if (strmatch(next, "isnan" )) d->type = e_isnan;
432  else if (strmatch(next, "isinf" )) d->type = e_isinf;
433  else if (strmatch(next, "st" )) d->type = e_st;
434  else if (strmatch(next, "while" )) d->type = e_while;
435  else if (strmatch(next, "taylor")) d->type = e_taylor;
436  else if (strmatch(next, "root" )) d->type = e_root;
437  else if (strmatch(next, "floor" )) d->type = e_floor;
438  else if (strmatch(next, "ceil" )) d->type = e_ceil;
439  else if (strmatch(next, "trunc" )) d->type = e_trunc;
440  else if (strmatch(next, "sqrt" )) d->type = e_sqrt;
441  else if (strmatch(next, "not" )) d->type = e_not;
442  else if (strmatch(next, "pow" )) d->type = e_pow;
443  else if (strmatch(next, "print" )) d->type = e_print;
444  else if (strmatch(next, "random")) d->type = e_random;
445  else if (strmatch(next, "hypot" )) d->type = e_hypot;
446  else if (strmatch(next, "gcd" )) d->type = e_gcd;
447  else if (strmatch(next, "if" )) d->type = e_if;
448  else if (strmatch(next, "ifnot" )) d->type = e_ifnot;
449  else if (strmatch(next, "bitand")) d->type = e_bitand;
450  else if (strmatch(next, "bitor" )) d->type = e_bitor;
451  else if (strmatch(next, "between"))d->type = e_between;
452  else if (strmatch(next, "clip" )) d->type = e_clip;
453  else {
454  for (i=0; p->func1_names && p->func1_names[i]; i++) {
455  if (strmatch(next, p->func1_names[i])) {
456  d->a.func1 = p->funcs1[i];
457  d->type = e_func1;
458  *e = d;
459  return 0;
460  }
461  }
462 
463  for (i=0; p->func2_names && p->func2_names[i]; i++) {
464  if (strmatch(next, p->func2_names[i])) {
465  d->a.func2 = p->funcs2[i];
466  d->type = e_func2;
467  *e = d;
468  return 0;
469  }
470  }
471 
472  av_log(p, AV_LOG_ERROR, "Unknown function in '%s'\n", s0);
473  av_expr_free(d);
474  return AVERROR(EINVAL);
475  }
476 
477  *e = d;
478  return 0;
479 }
480 
481 static AVExpr *make_eval_expr(int type, int value, AVExpr *p0, AVExpr *p1)
482 {
483  AVExpr *e = av_mallocz(sizeof(AVExpr));
484  if (!e)
485  return NULL;
486  e->type =type ;
487  e->value =value ;
488  e->param[0] =p0 ;
489  e->param[1] =p1 ;
490  return e;
491 }
492 
493 static int parse_pow(AVExpr **e, Parser *p, int *sign)
494 {
495  *sign= (*p->s == '+') - (*p->s == '-');
496  p->s += *sign&1;
497  return parse_primary(e, p);
498 }
499 
500 static int parse_dB(AVExpr **e, Parser *p, int *sign)
501 {
502  /* do not filter out the negative sign when parsing a dB value.
503  for example, -3dB is not the same as -(3dB) */
504  if (*p->s == '-') {
505  char *next;
506  double av_unused ignored = strtod(p->s, &next);
507  if (next != p->s && next[0] == 'd' && next[1] == 'B') {
508  *sign = 0;
509  return parse_primary(e, p);
510  }
511  }
512  return parse_pow(e, p, sign);
513 }
514 
515 static int parse_factor(AVExpr **e, Parser *p)
516 {
517  int sign, sign2, ret;
518  AVExpr *e0, *e1, *e2;
519  if ((ret = parse_dB(&e0, p, &sign)) < 0)
520  return ret;
521  while(p->s[0]=='^'){
522  e1 = e0;
523  p->s++;
524  if ((ret = parse_dB(&e2, p, &sign2)) < 0) {
525  av_expr_free(e1);
526  return ret;
527  }
528  e0 = make_eval_expr(e_pow, 1, e1, e2);
529  if (!e0) {
530  av_expr_free(e1);
531  av_expr_free(e2);
532  return AVERROR(ENOMEM);
533  }
534  if (e0->param[1]) e0->param[1]->value *= (sign2|1);
535  }
536  if (e0) e0->value *= (sign|1);
537 
538  *e = e0;
539  return 0;
540 }
541 
542 static int parse_term(AVExpr **e, Parser *p)
543 {
544  int ret;
545  AVExpr *e0, *e1, *e2;
546  if ((ret = parse_factor(&e0, p)) < 0)
547  return ret;
548  while (p->s[0]=='*' || p->s[0]=='/') {
549  int c= *p->s++;
550  e1 = e0;
551  if ((ret = parse_factor(&e2, p)) < 0) {
552  av_expr_free(e1);
553  return ret;
554  }
555  e0 = make_eval_expr(c == '*' ? e_mul : e_div, 1, e1, e2);
556  if (!e0) {
557  av_expr_free(e1);
558  av_expr_free(e2);
559  return AVERROR(ENOMEM);
560  }
561  }
562  *e = e0;
563  return 0;
564 }
565 
566 static int parse_subexpr(AVExpr **e, Parser *p)
567 {
568  int ret;
569  AVExpr *e0, *e1, *e2;
570  if ((ret = parse_term(&e0, p)) < 0)
571  return ret;
572  while (*p->s == '+' || *p->s == '-') {
573  e1 = e0;
574  if ((ret = parse_term(&e2, p)) < 0) {
575  av_expr_free(e1);
576  return ret;
577  }
578  e0 = make_eval_expr(e_add, 1, e1, e2);
579  if (!e0) {
580  av_expr_free(e1);
581  av_expr_free(e2);
582  return AVERROR(ENOMEM);
583  }
584  };
585 
586  *e = e0;
587  return 0;
588 }
589 
590 static int parse_expr(AVExpr **e, Parser *p)
591 {
592  int ret;
593  AVExpr *e0, *e1, *e2;
594  if (p->stack_index <= 0) //protect against stack overflows
595  return AVERROR(EINVAL);
596  p->stack_index--;
597 
598  if ((ret = parse_subexpr(&e0, p)) < 0)
599  return ret;
600  while (*p->s == ';') {
601  p->s++;
602  e1 = e0;
603  if ((ret = parse_subexpr(&e2, p)) < 0) {
604  av_expr_free(e1);
605  return ret;
606  }
607  e0 = make_eval_expr(e_last, 1, e1, e2);
608  if (!e0) {
609  av_expr_free(e1);
610  av_expr_free(e2);
611  return AVERROR(ENOMEM);
612  }
613  };
614 
615  p->stack_index++;
616  *e = e0;
617  return 0;
618 }
619 
620 static int verify_expr(AVExpr *e)
621 {
622  if (!e) return 0;
623  switch (e->type) {
624  case e_value:
625  case e_const: return 1;
626  case e_func0:
627  case e_func1:
628  case e_squish:
629  case e_ld:
630  case e_gauss:
631  case e_isnan:
632  case e_isinf:
633  case e_floor:
634  case e_ceil:
635  case e_trunc:
636  case e_sqrt:
637  case e_not:
638  case e_random:
639  return verify_expr(e->param[0]) && !e->param[1];
640  case e_print:
641  return verify_expr(e->param[0])
642  && (!e->param[1] || verify_expr(e->param[1]));
643  case e_if:
644  case e_ifnot:
645  case e_taylor:
646  return verify_expr(e->param[0]) && verify_expr(e->param[1])
647  && (!e->param[2] || verify_expr(e->param[2]));
648  case e_between:
649  case e_clip:
650  return verify_expr(e->param[0]) &&
651  verify_expr(e->param[1]) &&
652  verify_expr(e->param[2]);
653  default: return verify_expr(e->param[0]) && verify_expr(e->param[1]) && !e->param[2];
654  }
655 }
656 
657 int av_expr_parse(AVExpr **expr, const char *s,
658  const char * const *const_names,
659  const char * const *func1_names, double (* const *funcs1)(void *, double),
660  const char * const *func2_names, double (* const *funcs2)(void *, double, double),
661  int log_offset, void *log_ctx)
662 {
663  Parser p = { 0 };
664  AVExpr *e = NULL;
665  char *w = av_malloc(strlen(s) + 1);
666  char *wp = w;
667  const char *s0 = s;
668  int ret = 0;
669 
670  if (!w)
671  return AVERROR(ENOMEM);
672 
673  while (*s)
674  if (!av_isspace(*s++)) *wp++ = s[-1];
675  *wp++ = 0;
676 
677  p.class = &eval_class;
678  p.stack_index=100;
679  p.s= w;
680  p.const_names = const_names;
681  p.funcs1 = funcs1;
683  p.funcs2 = funcs2;
684  p.func2_names = func2_names;
685  p.log_offset = log_offset;
686  p.log_ctx = log_ctx;
687 
688  if ((ret = parse_expr(&e, &p)) < 0)
689  goto end;
690  if (*p.s) {
691  av_log(&p, AV_LOG_ERROR, "Invalid chars '%s' at the end of expression '%s'\n", p.s, s0);
692  ret = AVERROR(EINVAL);
693  goto end;
694  }
695  if (!verify_expr(e)) {
696  ret = AVERROR(EINVAL);
697  goto end;
698  }
699  e->var= av_mallocz(sizeof(double) *VARS);
700  if (!e->var) {
701  ret = AVERROR(ENOMEM);
702  goto end;
703  }
704  *expr = e;
705  e = NULL;
706 end:
707  av_expr_free(e);
708  av_free(w);
709  return ret;
710 }
711 
712 double av_expr_eval(AVExpr *e, const double *const_values, void *opaque)
713 {
714  Parser p = { 0 };
715  p.var= e->var;
716 
717  p.const_values = const_values;
718  p.opaque = opaque;
719  return eval_expr(&p, e);
720 }
721 
722 int av_expr_parse_and_eval(double *d, const char *s,
723  const char * const *const_names, const double *const_values,
724  const char * const *func1_names, double (* const *funcs1)(void *, double),
725  const char * const *func2_names, double (* const *funcs2)(void *, double, double),
726  void *opaque, int log_offset, void *log_ctx)
727 {
728  AVExpr *e = NULL;
729  int ret = av_expr_parse(&e, s, const_names, func1_names, funcs1, func2_names, funcs2, log_offset, log_ctx);
730 
731  if (ret < 0) {
732  *d = NAN;
733  return ret;
734  }
735  *d = av_expr_eval(e, const_values, opaque);
736  av_expr_free(e);
737  return isnan(*d) ? AVERROR(EINVAL) : 0;
738 }
739 
740 #ifdef TEST
741 #include <string.h>
742 
743 static const double const_values[] = {
744  M_PI,
745  M_E,
746  0
747 };
748 
749 static const char *const const_names[] = {
750  "PI",
751  "E",
752  0
753 };
754 
755 int main(int argc, char **argv)
756 {
757  int i;
758  double d;
759  const char *const *expr;
760  static const char *const exprs[] = {
761  "",
762  "1;2",
763  "-20",
764  "-PI",
765  "+PI",
766  "1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)",
767  "80G/80Gi",
768  "1k",
769  "1Gi",
770  "1gi",
771  "1GiFoo",
772  "1k+1k",
773  "1Gi*3foo",
774  "foo",
775  "foo(",
776  "foo()",
777  "foo)",
778  "sin",
779  "sin(",
780  "sin()",
781  "sin)",
782  "sin 10",
783  "sin(1,2,3)",
784  "sin(1 )",
785  "1",
786  "1foo",
787  "bar + PI + E + 100f*2 + foo",
788  "13k + 12f - foo(1, 2)",
789  "1gi",
790  "1Gi",
791  "st(0, 123)",
792  "st(1, 123); ld(1)",
793  "lte(0, 1)",
794  "lte(1, 1)",
795  "lte(1, 0)",
796  "lt(0, 1)",
797  "lt(1, 1)",
798  "gt(1, 0)",
799  "gt(2, 7)",
800  "gte(122, 122)",
801  /* compute 1+2+...+N */
802  "st(0, 1); while(lte(ld(0), 100), st(1, ld(1)+ld(0));st(0, ld(0)+1)); ld(1)",
803  /* compute Fib(N) */
804  "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)",
805  "while(0, 10)",
806  "st(0, 1); while(lte(ld(0),100), st(1, ld(1)+ld(0)); st(0, ld(0)+1))",
807  "isnan(1)",
808  "isnan(NAN)",
809  "isnan(INF)",
810  "isinf(1)",
811  "isinf(NAN)",
812  "isinf(INF)",
813  "floor(NAN)",
814  "floor(123.123)",
815  "floor(-123.123)",
816  "trunc(123.123)",
817  "trunc(-123.123)",
818  "ceil(123.123)",
819  "ceil(-123.123)",
820  "sqrt(1764)",
821  "isnan(sqrt(-1))",
822  "not(1)",
823  "not(NAN)",
824  "not(0)",
825  "6.0206dB",
826  "-3.0103dB",
827  "pow(0,1.23)",
828  "pow(PI,1.23)",
829  "PI^1.23",
830  "pow(-1,1.23)",
831  "if(1, 2)",
832  "if(1, 1, 2)",
833  "if(0, 1, 2)",
834  "ifnot(0, 23)",
835  "ifnot(1, NaN) + if(0, 1)",
836  "ifnot(1, 1, 2)",
837  "ifnot(0, 1, 2)",
838  "taylor(1, 1)",
839  "taylor(eq(mod(ld(1),4),1)-eq(mod(ld(1),4),3), PI/2, 1)",
840  "root(sin(ld(0))-1, 2)",
841  "root(sin(ld(0))+6+sin(ld(0)/12)-log(ld(0)), 100)",
842  "7000000B*random(0)",
843  "squish(2)",
844  "gauss(0.1)",
845  "hypot(4,3)",
846  "gcd(30,55)*print(min(9,1))",
847  "bitor(42, 12)",
848  "bitand(42, 12)",
849  "bitand(NAN, 1)",
850  "between(10, -3, 10)",
851  "between(-4, -2, -1)",
852  "between(1,2)",
853  "clip(0, 2, 1)",
854  "clip(0/0, 1, 2)",
855  "clip(0, 0/0, 1)",
856  NULL
857  };
858 
859  for (expr = exprs; *expr; expr++) {
860  printf("Evaluating '%s'\n", *expr);
861  av_expr_parse_and_eval(&d, *expr,
862  const_names, const_values,
863  NULL, NULL, NULL, NULL, NULL, 0, NULL);
864  if (isnan(d))
865  printf("'%s' -> nan\n\n", *expr);
866  else
867  printf("'%s' -> %f\n\n", *expr, d);
868  }
869 
870  av_expr_parse_and_eval(&d, "1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)",
871  const_names, const_values,
872  NULL, NULL, NULL, NULL, NULL, 0, NULL);
873  printf("%f == 12.7\n", d);
874  av_expr_parse_and_eval(&d, "80G/80Gi",
875  const_names, const_values,
876  NULL, NULL, NULL, NULL, NULL, 0, NULL);
877  printf("%f == 0.931322575\n", d);
878 
879  if (argc > 1 && !strcmp(argv[1], "-t")) {
880  for (i = 0; i < 1050; i++) {
881  START_TIMER;
882  av_expr_parse_and_eval(&d, "1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)",
883  const_names, const_values,
884  NULL, NULL, NULL, NULL, NULL, 0, NULL);
885  STOP_TIMER("av_expr_parse_and_eval");
886  }
887  }
888 
889  return 0;
890 }
891 #endif
#define VARS
Definition: eval.c:54
static int verify_expr(AVExpr *e)
Definition: eval.c:620
const char *const * func1_names
Definition: eval.c:48
#define NULL
Definition: coverity.c:32
const char * s
Definition: avisynth_c.h:631
static const char *const func1_names[]
Definition: vf_rotate.c:184
#define isinf(x)
Definition: libm.h:317
enum AVCodecID id
Definition: mxfenc.c:104
#define LIBAVUTIL_VERSION_INT
Definition: version.h:70
const char * b
Definition: vf_curves.c:109
static av_const int av_isspace(int c)
Locale-independent conversion of ASCII isspace.
Definition: avstring.h:222
external API header
int av_expr_parse(AVExpr **expr, const char *s, const char *const *const_names, const char *const *func1_names, double(*const *funcs1)(void *, double), const char *const *func2_names, double(*const *funcs2)(void *, double, double), int log_offset, void *log_ctx)
Parse an expression.
Definition: eval.c:657
void * log_ctx
Definition: eval.c:53
Macro definitions for various function/variable attributes.
static const struct @195 constants[]
static int parse_dB(AVExpr **e, Parser *p, int *sign)
Definition: eval.c:500
#define av_malloc(s)
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:90
static int parse_expr(AVExpr **e, Parser *p)
Definition: eval.c:590
Definition: eval.c:41
static double(*const funcs1[])(void *, double)
Definition: vf_lut.c:189
Definition: eval.c:148
double strtod(const char *, char **)
union AVExpr::@197 a
const char *const * const_names
Definition: eval.c:46
double(* func1)(void *, double)
Definition: eval.c:162
static int parse_pow(AVExpr **e, Parser *p, int *sign)
Definition: eval.c:493
static int parse_factor(AVExpr **e, Parser *p)
Definition: eval.c:515
high precision timer, useful to profile code
#define av_log(a,...)
static int parse_subexpr(AVExpr **e, Parser *p)
Definition: eval.c:566
double(* func2)(void *, double, double)
Definition: eval.c:163
static const struct @194 si_prefixes['z'- 'E'+1]
int av_expr_parse_and_eval(double *d, const char *s, const char *const *const_names, const double *const_values, const char *const *func1_names, double(*const *funcs1)(void *, double), const char *const *func2_names, double(*const *funcs2)(void *, double, double), void *opaque, int log_offset, void *log_ctx)
Parse and evaluate an expression.
Definition: eval.c:722
const double * const_values
Definition: eval.c:45
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
#define IS_IDENTIFIER_CHAR(c)
Definition: eval.c:136
av_default_item_name
#define AVERROR(e)
Definition: error.h:43
int const_index
Definition: eval.c:160
#define M_E
Definition: mathematics.h:31
const uint8_t ff_reverse[256]
Definition: reverse.c:23
const char * r
Definition: vf_curves.c:107
#define s0
Definition: regdef.h:37
static int parse_term(AVExpr **e, Parser *p)
Definition: eval.c:542
int64_t av_gcd(int64_t a, int64_t b)
Compute the greatest common divisor of a and b.
Definition: mathematics.c:37
int8_t exp
Definition: eval.c:63
common internal API header
static av_const double hypot(double x, double y)
Definition: libm.h:366
static double etime(double v)
Definition: eval.c:169
GLsizei GLboolean const GLfloat * value
Definition: opengl_enc.c:109
static av_always_inline av_const double trunc(double x)
Definition: libm.h:458
static int strmatch(const char *s, const char *prefix)
Definition: eval.c:138
static int parse_primary(AVExpr **e, Parser *p)
Definition: eval.c:327
double bin_val
Definition: eval.c:61
#define FF_ARRAY_ELEMS(a)
void * opaque
Definition: eval.c:51
#define INFINITY
Definition: math.h:27
int64_t av_gettime(void)
Get the current time in microseconds.
Definition: time.c:39
double av_strtod(const char *numstr, char **tail)
Parse the string in numstr and return its value as a double.
Definition: eval.c:97
const AVClass * class
Definition: eval.c:42
#define AV_LOG_INFO
Standard information.
Definition: log.h:187
static double eval_expr(Parser *p, AVExpr *e)
Definition: eval.c:174
void av_expr_free(AVExpr *e)
Free a parsed expression previously created with av_expr_parse().
Definition: eval.c:317
#define START_TIMER
Definition: timer.h:94
double * var
Definition: eval.c:166
char * s
Definition: eval.c:44
GLint GLenum type
Definition: opengl_enc.c:105
double value
Definition: eval.c:89
Describe the class of an AVClass context structure.
Definition: log.h:67
static const AVClass eval_class
Definition: eval.c:58
double * var
Definition: eval.c:55
#define isnan(x)
Definition: libm.h:340
struct AVExpr * param[3]
Definition: eval.c:165
#define M_PHI
Definition: mathematics.h:43
double(*const funcs1)(void *, double a)
Definition: eval.c:47
const char *const * func2_names
Definition: eval.c:50
uint8_t level
Definition: svq3.c:150
common internal and external API header
static double c[64]
int stack_index
Definition: eval.c:43
#define STOP_TIMER(id)
Definition: timer.h:95
#define av_free(p)
double dec_val
Definition: eval.c:62
#define NAN
Definition: math.h:28
double(*const funcs2)(void *, double a, double b)
Definition: eval.c:49
double av_expr_eval(AVExpr *e, const double *const_values, void *opaque)
Evaluate a previously parsed expression.
Definition: eval.c:712
#define FF_QP2LAMBDA
factor to convert from H.263 QP to lambda
Definition: avutil.h:219
double(* func0)(double)
Definition: eval.c:161
static AVExpr * make_eval_expr(int type, int value, AVExpr *p0, AVExpr *p1)
Definition: eval.c:481
#define av_freep(p)
static av_always_inline double ff_exp10(double x)
Compute 10^x for floating point values.
Definition: internal.h:306
#define M_PI
Definition: mathematics.h:46
int log_offset
Definition: eval.c:52
const char * name
Definition: eval.c:88
int main(int argc, char **argv)
Definition: main.c:22
enum AVExpr::@196 type
float min
void * av_mallocz(size_t size)
Allocate a block of size bytes with alignment suitable for all memory accesses (including vectors if ...
Definition: mem.c:252
#define av_unused
Definition: attributes.h:126
double value
Definition: eval.c:158
simple arithmetic expression evaluator
const char * name
Definition: opengl_enc.c:103