FFmpeg  4.3
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 "ffmath.h"
35 #include "internal.h"
36 #include "log.h"
37 #include "mathematics.h"
38 #include "time.h"
39 #include "avstring.h"
40 #include "timer.h"
41 #include "reverse.h"
42 
43 typedef struct Parser {
44  const AVClass *class;
46  char *s;
47  const double *const_values;
48  const char * const *const_names; // NULL terminated
49  double (* const *funcs1)(void *, double a); // NULL terminated
50  const char * const *func1_names; // NULL terminated
51  double (* const *funcs2)(void *, double a, double b); // NULL terminated
52  const char * const *func2_names; // NULL terminated
53  void *opaque;
55  void *log_ctx;
56 #define VARS 10
57  double *var;
58 } Parser;
59 
60 static const AVClass eval_class = {
61  .class_name = "Eval",
62  .item_name = av_default_item_name,
63  .option = NULL,
64  .version = LIBAVUTIL_VERSION_INT,
65  .log_level_offset_offset = offsetof(Parser, log_offset),
66  .parent_log_context_offset = offsetof(Parser, log_ctx),
67 };
68 
69 static const struct {
70  double bin_val;
71  double dec_val;
72  int8_t exp;
73 } si_prefixes['z' - 'E' + 1] = {
74  ['y'-'E']= { 8.271806125530276749e-25, 1e-24, -24 },
75  ['z'-'E']= { 8.4703294725430034e-22, 1e-21, -21 },
76  ['a'-'E']= { 8.6736173798840355e-19, 1e-18, -18 },
77  ['f'-'E']= { 8.8817841970012523e-16, 1e-15, -15 },
78  ['p'-'E']= { 9.0949470177292824e-13, 1e-12, -12 },
79  ['n'-'E']= { 9.3132257461547852e-10, 1e-9, -9 },
80  ['u'-'E']= { 9.5367431640625e-7, 1e-6, -6 },
81  ['m'-'E']= { 9.765625e-4, 1e-3, -3 },
82  ['c'-'E']= { 9.8431332023036951e-3, 1e-2, -2 },
83  ['d'-'E']= { 9.921256574801246e-2, 1e-1, -1 },
84  ['h'-'E']= { 1.0159366732596479e2, 1e2, 2 },
85  ['k'-'E']= { 1.024e3, 1e3, 3 },
86  ['K'-'E']= { 1.024e3, 1e3, 3 },
87  ['M'-'E']= { 1.048576e6, 1e6, 6 },
88  ['G'-'E']= { 1.073741824e9, 1e9, 9 },
89  ['T'-'E']= { 1.099511627776e12, 1e12, 12 },
90  ['P'-'E']= { 1.125899906842624e15, 1e15, 15 },
91  ['E'-'E']= { 1.152921504606847e18, 1e18, 18 },
92  ['Z'-'E']= { 1.1805916207174113e21, 1e21, 21 },
93  ['Y'-'E']= { 1.2089258196146292e24, 1e24, 24 },
94 };
95 
96 static const struct {
97  const char *name;
98  double value;
99 } constants[] = {
100  { "E", M_E },
101  { "PI", M_PI },
102  { "PHI", M_PHI },
103  { "QP2LAMBDA", FF_QP2LAMBDA },
104 };
105 
106 double av_strtod(const char *numstr, char **tail)
107 {
108  double d;
109  char *next;
110  if(numstr[0]=='0' && (numstr[1]|0x20)=='x') {
111  d = strtoul(numstr, &next, 16);
112  } else
113  d = strtod(numstr, &next);
114  /* if parsing succeeded, check for and interpret postfixes */
115  if (next!=numstr) {
116  if (next[0] == 'd' && next[1] == 'B') {
117  /* treat dB as decibels instead of decibytes */
118  d = ff_exp10(d / 20);
119  next += 2;
120  } else if (*next >= 'E' && *next <= 'z') {
121  int e= si_prefixes[*next - 'E'].exp;
122  if (e) {
123  if (next[1] == 'i') {
124  d*= si_prefixes[*next - 'E'].bin_val;
125  next+=2;
126  } else {
127  d*= si_prefixes[*next - 'E'].dec_val;
128  next++;
129  }
130  }
131  }
132 
133  if (*next=='B') {
134  d*=8;
135  next++;
136  }
137  }
138  /* if requested, fill in tail with the position after the last parsed
139  character */
140  if (tail)
141  *tail = next;
142  return d;
143 }
144 
145 #define IS_IDENTIFIER_CHAR(c) ((c) - '0' <= 9U || (c) - 'a' <= 25U || (c) - 'A' <= 25U || (c) == '_')
146 
147 static int strmatch(const char *s, const char *prefix)
148 {
149  int i;
150  for (i=0; prefix[i]; i++) {
151  if (prefix[i] != s[i]) return 0;
152  }
153  /* return 1 only if the s identifier is terminated */
154  return !IS_IDENTIFIER_CHAR(s[i]);
155 }
156 
157 struct AVExpr {
158  enum {
159  e_value, e_const, e_func0, e_func1, e_func2,
160  e_squish, e_gauss, e_ld, e_isnan, e_isinf,
161  e_mod, e_max, e_min, e_eq, e_gt, e_gte, e_lte, e_lt,
162  e_pow, e_mul, e_div, e_add,
163  e_last, e_st, e_while, e_taylor, e_root, e_floor, e_ceil, e_trunc, e_round,
164  e_sqrt, e_not, e_random, e_hypot, e_gcd,
165  e_if, e_ifnot, e_print, e_bitand, e_bitor, e_between, e_clip, e_atan2, e_lerp,
167  } type;
168  double value; // is sign in other types
170  union {
171  double (*func0)(double);
172  double (*func1)(void *, double);
173  double (*func2)(void *, double, double);
174  } a;
175  struct AVExpr *param[3];
176  double *var;
177 };
178 
179 static double etime(double v)
180 {
181  return av_gettime() * 0.000001;
182 }
183 
184 static double eval_expr(Parser *p, AVExpr *e)
185 {
186  switch (e->type) {
187  case e_value: return e->value;
188  case e_const: return e->value * p->const_values[e->const_index];
189  case e_func0: return e->value * e->a.func0(eval_expr(p, e->param[0]));
190  case e_func1: return e->value * e->a.func1(p->opaque, eval_expr(p, e->param[0]));
191  case e_func2: return e->value * e->a.func2(p->opaque, eval_expr(p, e->param[0]), eval_expr(p, e->param[1]));
192  case e_squish: return 1/(1+exp(4*eval_expr(p, e->param[0])));
193  case e_gauss: { double d = eval_expr(p, e->param[0]); return exp(-d*d/2)/sqrt(2*M_PI); }
194  case e_ld: return e->value * p->var[av_clip(eval_expr(p, e->param[0]), 0, VARS-1)];
195  case e_isnan: return e->value * !!isnan(eval_expr(p, e->param[0]));
196  case e_isinf: return e->value * !!isinf(eval_expr(p, e->param[0]));
197  case e_floor: return e->value * floor(eval_expr(p, e->param[0]));
198  case e_ceil : return e->value * ceil (eval_expr(p, e->param[0]));
199  case e_trunc: return e->value * trunc(eval_expr(p, e->param[0]));
200  case e_round: return e->value * round(eval_expr(p, e->param[0]));
201  case e_sgn: return e->value * FFDIFFSIGN(eval_expr(p, e->param[0]), 0);
202  case e_sqrt: return e->value * sqrt (eval_expr(p, e->param[0]));
203  case e_not: return e->value * (eval_expr(p, e->param[0]) == 0);
204  case e_if: return e->value * (eval_expr(p, e->param[0]) ? eval_expr(p, e->param[1]) :
205  e->param[2] ? eval_expr(p, e->param[2]) : 0);
206  case e_ifnot: return e->value * (!eval_expr(p, e->param[0]) ? eval_expr(p, e->param[1]) :
207  e->param[2] ? eval_expr(p, e->param[2]) : 0);
208  case e_clip: {
209  double x = eval_expr(p, e->param[0]);
210  double min = eval_expr(p, e->param[1]), max = eval_expr(p, e->param[2]);
211  if (isnan(min) || isnan(max) || isnan(x) || min > max)
212  return NAN;
213  return e->value * av_clipd(eval_expr(p, e->param[0]), min, max);
214  }
215  case e_between: {
216  double d = eval_expr(p, e->param[0]);
217  return e->value * (d >= eval_expr(p, e->param[1]) &&
218  d <= eval_expr(p, e->param[2]));
219  }
220  case e_lerp: {
221  double v0 = eval_expr(p, e->param[0]);
222  double v1 = eval_expr(p, e->param[1]);
223  double f = eval_expr(p, e->param[2]);
224  return v0 + (v1 - v0) * f;
225  }
226  case e_print: {
227  double x = eval_expr(p, e->param[0]);
228  int level = e->param[1] ? av_clip(eval_expr(p, e->param[1]), INT_MIN, INT_MAX) : AV_LOG_INFO;
229  av_log(p, level, "%f\n", x);
230  return x;
231  }
232  case e_random:{
233  int idx= av_clip(eval_expr(p, e->param[0]), 0, VARS-1);
234  uint64_t r= isnan(p->var[idx]) ? 0 : p->var[idx];
235  r= r*1664525+1013904223;
236  p->var[idx]= r;
237  return e->value * (r * (1.0/UINT64_MAX));
238  }
239  case e_while: {
240  double d = NAN;
241  while (eval_expr(p, e->param[0]))
242  d=eval_expr(p, e->param[1]);
243  return d;
244  }
245  case e_taylor: {
246  double t = 1, d = 0, v;
247  double x = eval_expr(p, e->param[1]);
248  int id = e->param[2] ? av_clip(eval_expr(p, e->param[2]), 0, VARS-1) : 0;
249  int i;
250  double var0 = p->var[id];
251  for(i=0; i<1000; i++) {
252  double ld = d;
253  p->var[id] = i;
254  v = eval_expr(p, e->param[0]);
255  d += t*v;
256  if(ld==d && v)
257  break;
258  t *= x / (i+1);
259  }
260  p->var[id] = var0;
261  return d;
262  }
263  case e_root: {
264  int i, j;
265  double low = -1, high = -1, v, low_v = -DBL_MAX, high_v = DBL_MAX;
266  double var0 = p->var[0];
267  double x_max = eval_expr(p, e->param[1]);
268  for(i=-1; i<1024; i++) {
269  if(i<255) {
270  p->var[0] = ff_reverse[i&255]*x_max/255;
271  } else {
272  p->var[0] = x_max*pow(0.9, i-255);
273  if (i&1) p->var[0] *= -1;
274  if (i&2) p->var[0] += low;
275  else p->var[0] += high;
276  }
277  v = eval_expr(p, e->param[0]);
278  if (v<=0 && v>low_v) {
279  low = p->var[0];
280  low_v = v;
281  }
282  if (v>=0 && v<high_v) {
283  high = p->var[0];
284  high_v = v;
285  }
286  if (low>=0 && high>=0){
287  for (j=0; j<1000; j++) {
288  p->var[0] = (low+high)*0.5;
289  if (low == p->var[0] || high == p->var[0])
290  break;
291  v = eval_expr(p, e->param[0]);
292  if (v<=0) low = p->var[0];
293  if (v>=0) high= p->var[0];
294  if (isnan(v)) {
295  low = high = v;
296  break;
297  }
298  }
299  break;
300  }
301  }
302  p->var[0] = var0;
303  return -low_v<high_v ? low : high;
304  }
305  default: {
306  double d = eval_expr(p, e->param[0]);
307  double d2 = eval_expr(p, e->param[1]);
308  switch (e->type) {
309  case e_mod: return e->value * (d - floor((!CONFIG_FTRAPV || d2) ? d / d2 : d * INFINITY) * d2);
310  case e_gcd: return e->value * av_gcd(d,d2);
311  case e_max: return e->value * (d > d2 ? d : d2);
312  case e_min: return e->value * (d < d2 ? d : d2);
313  case e_eq: return e->value * (d == d2 ? 1.0 : 0.0);
314  case e_gt: return e->value * (d > d2 ? 1.0 : 0.0);
315  case e_gte: return e->value * (d >= d2 ? 1.0 : 0.0);
316  case e_lt: return e->value * (d < d2 ? 1.0 : 0.0);
317  case e_lte: return e->value * (d <= d2 ? 1.0 : 0.0);
318  case e_pow: return e->value * pow(d, d2);
319  case e_mul: return e->value * (d * d2);
320  case e_div: return e->value * ((!CONFIG_FTRAPV || d2 ) ? (d / d2) : d * INFINITY);
321  case e_add: return e->value * (d + d2);
322  case e_last:return e->value * d2;
323  case e_st : return e->value * (p->var[av_clip(d, 0, VARS-1)]= d2);
324  case e_hypot:return e->value * hypot(d, d2);
325  case e_atan2:return e->value * atan2(d, d2);
326  case e_bitand: return isnan(d) || isnan(d2) ? NAN : e->value * ((long int)d & (long int)d2);
327  case e_bitor: return isnan(d) || isnan(d2) ? NAN : e->value * ((long int)d | (long int)d2);
328  }
329  }
330  }
331  return NAN;
332 }
333 
334 static int parse_expr(AVExpr **e, Parser *p);
335 
337 {
338  if (!e) return;
339  av_expr_free(e->param[0]);
340  av_expr_free(e->param[1]);
341  av_expr_free(e->param[2]);
342  av_freep(&e->var);
343  av_freep(&e);
344 }
345 
346 static int parse_primary(AVExpr **e, Parser *p)
347 {
348  AVExpr *d = av_mallocz(sizeof(AVExpr));
349  char *next = p->s, *s0 = p->s;
350  int ret, i;
351 
352  if (!d)
353  return AVERROR(ENOMEM);
354 
355  /* number */
356  d->value = av_strtod(p->s, &next);
357  if (next != p->s) {
358  d->type = e_value;
359  p->s= next;
360  *e = d;
361  return 0;
362  }
363  d->value = 1;
364 
365  /* named constants */
366  for (i=0; p->const_names && p->const_names[i]; i++) {
367  if (strmatch(p->s, p->const_names[i])) {
368  p->s+= strlen(p->const_names[i]);
369  d->type = e_const;
370  d->const_index = i;
371  *e = d;
372  return 0;
373  }
374  }
375  for (i = 0; i < FF_ARRAY_ELEMS(constants); i++) {
376  if (strmatch(p->s, constants[i].name)) {
377  p->s += strlen(constants[i].name);
378  d->type = e_value;
379  d->value = constants[i].value;
380  *e = d;
381  return 0;
382  }
383  }
384 
385  p->s= strchr(p->s, '(');
386  if (!p->s) {
387  av_log(p, AV_LOG_ERROR, "Undefined constant or missing '(' in '%s'\n", s0);
388  p->s= next;
389  av_expr_free(d);
390  return AVERROR(EINVAL);
391  }
392  p->s++; // "("
393  if (*next == '(') { // special case do-nothing
394  av_freep(&d);
395  if ((ret = parse_expr(&d, p)) < 0)
396  return ret;
397  if (p->s[0] != ')') {
398  av_log(p, AV_LOG_ERROR, "Missing ')' in '%s'\n", s0);
399  av_expr_free(d);
400  return AVERROR(EINVAL);
401  }
402  p->s++; // ")"
403  *e = d;
404  return 0;
405  }
406  if ((ret = parse_expr(&(d->param[0]), p)) < 0) {
407  av_expr_free(d);
408  return ret;
409  }
410  if (p->s[0]== ',') {
411  p->s++; // ","
412  parse_expr(&d->param[1], p);
413  }
414  if (p->s[0]== ',') {
415  p->s++; // ","
416  parse_expr(&d->param[2], p);
417  }
418  if (p->s[0] != ')') {
419  av_log(p, AV_LOG_ERROR, "Missing ')' or too many args in '%s'\n", s0);
420  av_expr_free(d);
421  return AVERROR(EINVAL);
422  }
423  p->s++; // ")"
424 
425  d->type = e_func0;
426  if (strmatch(next, "sinh" )) d->a.func0 = sinh;
427  else if (strmatch(next, "cosh" )) d->a.func0 = cosh;
428  else if (strmatch(next, "tanh" )) d->a.func0 = tanh;
429  else if (strmatch(next, "sin" )) d->a.func0 = sin;
430  else if (strmatch(next, "cos" )) d->a.func0 = cos;
431  else if (strmatch(next, "tan" )) d->a.func0 = tan;
432  else if (strmatch(next, "atan" )) d->a.func0 = atan;
433  else if (strmatch(next, "asin" )) d->a.func0 = asin;
434  else if (strmatch(next, "acos" )) d->a.func0 = acos;
435  else if (strmatch(next, "exp" )) d->a.func0 = exp;
436  else if (strmatch(next, "log" )) d->a.func0 = log;
437  else if (strmatch(next, "abs" )) d->a.func0 = fabs;
438  else if (strmatch(next, "time" )) d->a.func0 = etime;
439  else if (strmatch(next, "squish")) d->type = e_squish;
440  else if (strmatch(next, "gauss" )) d->type = e_gauss;
441  else if (strmatch(next, "mod" )) d->type = e_mod;
442  else if (strmatch(next, "max" )) d->type = e_max;
443  else if (strmatch(next, "min" )) d->type = e_min;
444  else if (strmatch(next, "eq" )) d->type = e_eq;
445  else if (strmatch(next, "gte" )) d->type = e_gte;
446  else if (strmatch(next, "gt" )) d->type = e_gt;
447  else if (strmatch(next, "lte" )) d->type = e_lte;
448  else if (strmatch(next, "lt" )) d->type = e_lt;
449  else if (strmatch(next, "ld" )) d->type = e_ld;
450  else if (strmatch(next, "isnan" )) d->type = e_isnan;
451  else if (strmatch(next, "isinf" )) d->type = e_isinf;
452  else if (strmatch(next, "st" )) d->type = e_st;
453  else if (strmatch(next, "while" )) d->type = e_while;
454  else if (strmatch(next, "taylor")) d->type = e_taylor;
455  else if (strmatch(next, "root" )) d->type = e_root;
456  else if (strmatch(next, "floor" )) d->type = e_floor;
457  else if (strmatch(next, "ceil" )) d->type = e_ceil;
458  else if (strmatch(next, "trunc" )) d->type = e_trunc;
459  else if (strmatch(next, "round" )) d->type = e_round;
460  else if (strmatch(next, "sqrt" )) d->type = e_sqrt;
461  else if (strmatch(next, "not" )) d->type = e_not;
462  else if (strmatch(next, "pow" )) d->type = e_pow;
463  else if (strmatch(next, "print" )) d->type = e_print;
464  else if (strmatch(next, "random")) d->type = e_random;
465  else if (strmatch(next, "hypot" )) d->type = e_hypot;
466  else if (strmatch(next, "gcd" )) d->type = e_gcd;
467  else if (strmatch(next, "if" )) d->type = e_if;
468  else if (strmatch(next, "ifnot" )) d->type = e_ifnot;
469  else if (strmatch(next, "bitand")) d->type = e_bitand;
470  else if (strmatch(next, "bitor" )) d->type = e_bitor;
471  else if (strmatch(next, "between"))d->type = e_between;
472  else if (strmatch(next, "clip" )) d->type = e_clip;
473  else if (strmatch(next, "atan2" )) d->type = e_atan2;
474  else if (strmatch(next, "lerp" )) d->type = e_lerp;
475  else if (strmatch(next, "sgn" )) d->type = e_sgn;
476  else {
477  for (i=0; p->func1_names && p->func1_names[i]; i++) {
478  if (strmatch(next, p->func1_names[i])) {
479  d->a.func1 = p->funcs1[i];
480  d->type = e_func1;
481  d->const_index = i;
482  *e = d;
483  return 0;
484  }
485  }
486 
487  for (i=0; p->func2_names && p->func2_names[i]; i++) {
488  if (strmatch(next, p->func2_names[i])) {
489  d->a.func2 = p->funcs2[i];
490  d->type = e_func2;
491  d->const_index = i;
492  *e = d;
493  return 0;
494  }
495  }
496 
497  av_log(p, AV_LOG_ERROR, "Unknown function in '%s'\n", s0);
498  av_expr_free(d);
499  return AVERROR(EINVAL);
500  }
501 
502  *e = d;
503  return 0;
504 }
505 
506 static AVExpr *make_eval_expr(int type, int value, AVExpr *p0, AVExpr *p1)
507 {
508  AVExpr *e = av_mallocz(sizeof(AVExpr));
509  if (!e)
510  return NULL;
511  e->type =type ;
512  e->value =value ;
513  e->param[0] =p0 ;
514  e->param[1] =p1 ;
515  return e;
516 }
517 
518 static int parse_pow(AVExpr **e, Parser *p, int *sign)
519 {
520  *sign= (*p->s == '+') - (*p->s == '-');
521  p->s += *sign&1;
522  return parse_primary(e, p);
523 }
524 
525 static int parse_dB(AVExpr **e, Parser *p, int *sign)
526 {
527  /* do not filter out the negative sign when parsing a dB value.
528  for example, -3dB is not the same as -(3dB) */
529  if (*p->s == '-') {
530  char *next;
531  double av_unused ignored = strtod(p->s, &next);
532  if (next != p->s && next[0] == 'd' && next[1] == 'B') {
533  *sign = 0;
534  return parse_primary(e, p);
535  }
536  }
537  return parse_pow(e, p, sign);
538 }
539 
540 static int parse_factor(AVExpr **e, Parser *p)
541 {
542  int sign, sign2, ret;
543  AVExpr *e0, *e1, *e2;
544  if ((ret = parse_dB(&e0, p, &sign)) < 0)
545  return ret;
546  while(p->s[0]=='^'){
547  e1 = e0;
548  p->s++;
549  if ((ret = parse_dB(&e2, p, &sign2)) < 0) {
550  av_expr_free(e1);
551  return ret;
552  }
553  e0 = make_eval_expr(e_pow, 1, e1, e2);
554  if (!e0) {
555  av_expr_free(e1);
556  av_expr_free(e2);
557  return AVERROR(ENOMEM);
558  }
559  if (e0->param[1]) e0->param[1]->value *= (sign2|1);
560  }
561  if (e0) e0->value *= (sign|1);
562 
563  *e = e0;
564  return 0;
565 }
566 
567 static int parse_term(AVExpr **e, Parser *p)
568 {
569  int ret;
570  AVExpr *e0, *e1, *e2;
571  if ((ret = parse_factor(&e0, p)) < 0)
572  return ret;
573  while (p->s[0]=='*' || p->s[0]=='/') {
574  int c= *p->s++;
575  e1 = e0;
576  if ((ret = parse_factor(&e2, p)) < 0) {
577  av_expr_free(e1);
578  return ret;
579  }
580  e0 = make_eval_expr(c == '*' ? e_mul : e_div, 1, e1, e2);
581  if (!e0) {
582  av_expr_free(e1);
583  av_expr_free(e2);
584  return AVERROR(ENOMEM);
585  }
586  }
587  *e = e0;
588  return 0;
589 }
590 
591 static int parse_subexpr(AVExpr **e, Parser *p)
592 {
593  int ret;
594  AVExpr *e0, *e1, *e2;
595  if ((ret = parse_term(&e0, p)) < 0)
596  return ret;
597  while (*p->s == '+' || *p->s == '-') {
598  e1 = e0;
599  if ((ret = parse_term(&e2, p)) < 0) {
600  av_expr_free(e1);
601  return ret;
602  }
603  e0 = make_eval_expr(e_add, 1, e1, e2);
604  if (!e0) {
605  av_expr_free(e1);
606  av_expr_free(e2);
607  return AVERROR(ENOMEM);
608  }
609  };
610 
611  *e = e0;
612  return 0;
613 }
614 
615 static int parse_expr(AVExpr **e, Parser *p)
616 {
617  int ret;
618  AVExpr *e0, *e1, *e2;
619  if (p->stack_index <= 0) //protect against stack overflows
620  return AVERROR(EINVAL);
621  p->stack_index--;
622 
623  if ((ret = parse_subexpr(&e0, p)) < 0)
624  return ret;
625  while (*p->s == ';') {
626  p->s++;
627  e1 = e0;
628  if ((ret = parse_subexpr(&e2, p)) < 0) {
629  av_expr_free(e1);
630  return ret;
631  }
632  e0 = make_eval_expr(e_last, 1, e1, e2);
633  if (!e0) {
634  av_expr_free(e1);
635  av_expr_free(e2);
636  return AVERROR(ENOMEM);
637  }
638  };
639 
640  p->stack_index++;
641  *e = e0;
642  return 0;
643 }
644 
645 static int verify_expr(AVExpr *e)
646 {
647  if (!e) return 0;
648  switch (e->type) {
649  case e_value:
650  case e_const: return 1;
651  case e_func0:
652  case e_func1:
653  case e_squish:
654  case e_ld:
655  case e_gauss:
656  case e_isnan:
657  case e_isinf:
658  case e_floor:
659  case e_ceil:
660  case e_trunc:
661  case e_round:
662  case e_sqrt:
663  case e_not:
664  case e_random:
665  case e_sgn:
666  return verify_expr(e->param[0]) && !e->param[1];
667  case e_print:
668  return verify_expr(e->param[0])
669  && (!e->param[1] || verify_expr(e->param[1]));
670  case e_if:
671  case e_ifnot:
672  case e_taylor:
673  return verify_expr(e->param[0]) && verify_expr(e->param[1])
674  && (!e->param[2] || verify_expr(e->param[2]));
675  case e_between:
676  case e_clip:
677  case e_lerp:
678  return verify_expr(e->param[0]) &&
679  verify_expr(e->param[1]) &&
680  verify_expr(e->param[2]);
681  default: return verify_expr(e->param[0]) && verify_expr(e->param[1]) && !e->param[2];
682  }
683 }
684 
685 int av_expr_parse(AVExpr **expr, const char *s,
686  const char * const *const_names,
687  const char * const *func1_names, double (* const *funcs1)(void *, double),
688  const char * const *func2_names, double (* const *funcs2)(void *, double, double),
689  int log_offset, void *log_ctx)
690 {
691  Parser p = { 0 };
692  AVExpr *e = NULL;
693  char *w = av_malloc(strlen(s) + 1);
694  char *wp = w;
695  const char *s0 = s;
696  int ret = 0;
697 
698  if (!w)
699  return AVERROR(ENOMEM);
700 
701  while (*s)
702  if (!av_isspace(*s++)) *wp++ = s[-1];
703  *wp++ = 0;
704 
705  p.class = &eval_class;
706  p.stack_index=100;
707  p.s= w;
709  p.funcs1 = funcs1;
711  p.funcs2 = funcs2;
714  p.log_ctx = log_ctx;
715 
716  if ((ret = parse_expr(&e, &p)) < 0)
717  goto end;
718  if (*p.s) {
719  av_log(&p, AV_LOG_ERROR, "Invalid chars '%s' at the end of expression '%s'\n", p.s, s0);
720  ret = AVERROR(EINVAL);
721  goto end;
722  }
723  if (!verify_expr(e)) {
724  ret = AVERROR(EINVAL);
725  goto end;
726  }
727  e->var= av_mallocz(sizeof(double) *VARS);
728  if (!e->var) {
729  ret = AVERROR(ENOMEM);
730  goto end;
731  }
732  *expr = e;
733  e = NULL;
734 end:
735  av_expr_free(e);
736  av_free(w);
737  return ret;
738 }
739 
740 static int expr_count(AVExpr *e, unsigned *counter, int size, int type)
741 {
742  int i;
743 
744  if (!e || !counter || !size)
745  return AVERROR(EINVAL);
746 
747  for (i = 0; e->type != type && i < 3 && e->param[i]; i++)
748  expr_count(e->param[i], counter, size, type);
749 
750  if (e->type == type && e->const_index < size)
751  counter[e->const_index]++;
752 
753  return 0;
754 }
755 
756 int av_expr_count_vars(AVExpr *e, unsigned *counter, int size)
757 {
758  return expr_count(e, counter, size, e_const);
759 }
760 
761 int av_expr_count_func(AVExpr *e, unsigned *counter, int size, int arg)
762 {
763  return expr_count(e, counter, size, ((int[]){e_const, e_func1, e_func2})[arg]);
764 }
765 
766 double av_expr_eval(AVExpr *e, const double *const_values, void *opaque)
767 {
768  Parser p = { 0 };
769  p.var= e->var;
770 
772  p.opaque = opaque;
773  return eval_expr(&p, e);
774 }
775 
776 int av_expr_parse_and_eval(double *d, const char *s,
777  const char * const *const_names, const double *const_values,
778  const char * const *func1_names, double (* const *funcs1)(void *, double),
779  const char * const *func2_names, double (* const *funcs2)(void *, double, double),
780  void *opaque, int log_offset, void *log_ctx)
781 {
782  AVExpr *e = NULL;
783  int ret = av_expr_parse(&e, s, const_names, func1_names, funcs1, func2_names, funcs2, log_offset, log_ctx);
784 
785  if (ret < 0) {
786  *d = NAN;
787  return ret;
788  }
789  *d = av_expr_eval(e, const_values, opaque);
790  av_expr_free(e);
791  return isnan(*d) ? AVERROR(EINVAL) : 0;
792 }
#define VARS
Definition: eval.c:56
static int verify_expr(AVExpr *e)
Definition: eval.c:645
const char *const * func1_names
Definition: eval.c:50
#define NULL
Definition: coverity.c:32
int size
#define isinf(x)
Definition: libm.h:317
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
const uint8_t ff_reverse[256]
Definition: reverse.c:23
int av_expr_count_func(AVExpr *e, unsigned *counter, int size, int arg)
Track the presence of user provided functions and their number of occurrences in a parsed expression...
Definition: eval.c:761
enum AVExpr::@286 type
const char * b
Definition: vf_curves.c:116
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:235
static av_const int av_isspace(int c)
Locale-independent conversion of ASCII isspace.
Definition: avstring.h:222
Convenience header that includes libavutil&#39;s core.
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:685
void * log_ctx
Definition: eval.c:55
Macro definitions for various function/variable attributes.
const char * class_name
The name of the class; usually it is the same name as the context structure type to which the AVClass...
Definition: log.h:72
static int parse_dB(AVExpr **e, Parser *p, int *sign)
Definition: eval.c:525
#define av_malloc(s)
static const struct @285 constants[]
#define f(width, name)
Definition: cbs_vp9.c:255
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:90
union AVExpr::@287 a
static int parse_expr(AVExpr **e, Parser *p)
Definition: eval.c:615
Definition: eval.c:43
Definition: eval.c:157
double strtod(const char *, char **)
double(* func2)(void *, double, double)
Definition: eval.c:173
const char *const * const_names
Definition: eval.c:48
static int parse_pow(AVExpr **e, Parser *p, int *sign)
Definition: eval.c:518
static int parse_factor(AVExpr **e, Parser *p)
Definition: eval.c:540
#define max(a, b)
Definition: cuda_runtime.h:33
high precision timer, useful to profile code
#define av_log(a,...)
static int parse_subexpr(AVExpr **e, Parser *p)
Definition: eval.c:591
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:776
const double * const_values
Definition: eval.c:47
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:269
static av_always_inline double ff_exp10(double x)
Compute 10^x for floating point values.
Definition: ffmath.h:42
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
#define IS_IDENTIFIER_CHAR(c)
Definition: eval.c:145
static int expr_count(AVExpr *e, unsigned *counter, int size, int type)
Definition: eval.c:740
static double(*const func1[])(void *, double)
Definition: vf_rotate.c:190
#define AVERROR(e)
Definition: error.h:43
static const struct @284 si_prefixes[ 'z' - 'E'+1]
int const_index
Definition: eval.c:169
#define M_E
Definition: mathematics.h:37
const char * r
Definition: vf_curves.c:114
#define s0
Definition: regdef.h:37
const char * arg
Definition: jacosubdec.c:66
static int parse_term(AVExpr **e, Parser *p)
Definition: eval.c:567
int64_t av_gcd(int64_t a, int64_t b)
Compute the greatest common divisor of two integer operands.
Definition: mathematics.c:37
void * av_mallocz(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
Definition: mem.c:239
static av_always_inline av_const double round(double x)
Definition: libm.h:444
int8_t exp
Definition: eval.c:72
#define FFDIFFSIGN(x, y)
Comparator.
Definition: common.h:92
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:179
#define NAN
Definition: mathematics.h:64
uint8_t w
Definition: llviddspenc.c:38
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:147
static int parse_primary(AVExpr **e, Parser *p)
Definition: eval.c:346
double(*const funcs1)(void *, double a)
Definition: eval.c:49
double bin_val
Definition: eval.c:70
#define FF_ARRAY_ELEMS(a)
void * opaque
Definition: eval.c:53
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:106
const AVClass * class
Definition: eval.c:44
#define AV_LOG_INFO
Standard information.
Definition: log.h:187
static double eval_expr(Parser *p, AVExpr *e)
Definition: eval.c:184
void av_expr_free(AVExpr *e)
Free a parsed expression previously created with av_expr_parse().
Definition: eval.c:336
double * var
Definition: eval.c:176
double(* func2[])(void *, double, double)
Definition: af_afftfilt.c:121
char * s
Definition: eval.c:46
double value
Definition: eval.c:98
Describe the class of an AVClass context structure.
Definition: log.h:67
static const AVClass eval_class
Definition: eval.c:60
double(* func1)(void *, double)
Definition: eval.c:172
double * var
Definition: eval.c:57
#define isnan(x)
Definition: libm.h:340
struct AVExpr * param[3]
Definition: eval.c:175
cl_device_type type
#define M_PHI
Definition: mathematics.h:49
const char *const * func2_names
Definition: eval.c:52
uint8_t level
Definition: svq3.c:209
#define v0
Definition: regdef.h:26
internal math functions header
int
common internal and external API header
static double c[64]
int stack_index
Definition: eval.c:45
int av_expr_count_vars(AVExpr *e, unsigned *counter, int size)
Track the presence of variables and their number of occurrences in a parsed expression.
Definition: eval.c:756
#define av_free(p)
double dec_val
Definition: eval.c:71
double av_expr_eval(AVExpr *e, const double *const_values, void *opaque)
Evaluate a previously parsed expression.
Definition: eval.c:766
#define FF_QP2LAMBDA
factor to convert from H.263 QP to lambda
Definition: avutil.h:227
#define CONFIG_FTRAPV
Definition: config.h:548
static AVExpr * make_eval_expr(int type, int value, AVExpr *p0, AVExpr *p1)
Definition: eval.c:506
#define av_freep(p)
#define M_PI
Definition: mathematics.h:52
int log_offset
Definition: eval.c:54
double(*const funcs2)(void *, double a, double b)
Definition: eval.c:51
const char * name
Definition: eval.c:97
double(* func0)(double)
Definition: eval.c:171
#define INFINITY
Definition: mathematics.h:67
float min
enum AVCodecID id
#define av_unused
Definition: attributes.h:131
double value
Definition: eval.c:168
simple arithmetic expression evaluator