FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
eval.c
Go to the documentation of this file.
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 = { "Eval", av_default_item_name, NULL, LIBAVUTIL_VERSION_INT, offsetof(Parser,log_offset), offsetof(Parser,log_ctx) };
61 
62 static const struct {
63  double bin_val;
64  double dec_val;
65  int8_t exp;
66 } si_prefixes['z' - 'E' + 1] = {
67  ['y'-'E']= { 8.271806125530276749e-25, 1e-24, -24 },
68  ['z'-'E']= { 8.4703294725430034e-22, 1e-21, -21 },
69  ['a'-'E']= { 8.6736173798840355e-19, 1e-18, -18 },
70  ['f'-'E']= { 8.8817841970012523e-16, 1e-15, -15 },
71  ['p'-'E']= { 9.0949470177292824e-13, 1e-12, -12 },
72  ['n'-'E']= { 9.3132257461547852e-10, 1e-9, -9 },
73  ['u'-'E']= { 9.5367431640625e-7, 1e-6, -6 },
74  ['m'-'E']= { 9.765625e-4, 1e-3, -3 },
75  ['c'-'E']= { 9.8431332023036951e-3, 1e-2, -2 },
76  ['d'-'E']= { 9.921256574801246e-2, 1e-1, -1 },
77  ['h'-'E']= { 1.0159366732596479e2, 1e2, 2 },
78  ['k'-'E']= { 1.024e3, 1e3, 3 },
79  ['K'-'E']= { 1.024e3, 1e3, 3 },
80  ['M'-'E']= { 1.048576e6, 1e6, 6 },
81  ['G'-'E']= { 1.073741824e9, 1e9, 9 },
82  ['T'-'E']= { 1.099511627776e12, 1e12, 12 },
83  ['P'-'E']= { 1.125899906842624e15, 1e15, 15 },
84  ['E'-'E']= { 1.152921504606847e18, 1e18, 18 },
85  ['Z'-'E']= { 1.1805916207174113e21, 1e21, 21 },
86  ['Y'-'E']= { 1.2089258196146292e24, 1e24, 24 },
87 };
88 
89 static const struct {
90  const char *name;
91  double value;
92 } constants[] = {
93  { "E", M_E },
94  { "PI", M_PI },
95  { "PHI", M_PHI },
96  { "QP2LAMBDA", FF_QP2LAMBDA },
97 };
98 
99 double av_strtod(const char *numstr, char **tail)
100 {
101  double d;
102  char *next;
103  if(numstr[0]=='0' && (numstr[1]|0x20)=='x') {
104  d = strtoul(numstr, &next, 16);
105  } else
106  d = strtod(numstr, &next);
107  /* if parsing succeeded, check for and interpret postfixes */
108  if (next!=numstr) {
109  if (next[0] == 'd' && next[1] == 'B') {
110  /* treat dB as decibels instead of decibytes */
111  d = ff_exp10(d / 20);
112  next += 2;
113  } else if (*next >= 'E' && *next <= 'z') {
114  int e= si_prefixes[*next - 'E'].exp;
115  if (e) {
116  if (next[1] == 'i') {
117  d*= si_prefixes[*next - 'E'].bin_val;
118  next+=2;
119  } else {
120  d*= si_prefixes[*next - 'E'].dec_val;
121  next++;
122  }
123  }
124  }
125 
126  if (*next=='B') {
127  d*=8;
128  next++;
129  }
130  }
131  /* if requested, fill in tail with the position after the last parsed
132  character */
133  if (tail)
134  *tail = next;
135  return d;
136 }
137 
138 #define IS_IDENTIFIER_CHAR(c) ((c) - '0' <= 9U || (c) - 'a' <= 25U || (c) - 'A' <= 25U || (c) == '_')
139 
140 static int strmatch(const char *s, const char *prefix)
141 {
142  int i;
143  for (i=0; prefix[i]; i++) {
144  if (prefix[i] != s[i]) return 0;
145  }
146  /* return 1 only if the s identifier is terminated */
147  return !IS_IDENTIFIER_CHAR(s[i]);
148 }
149 
150 struct AVExpr {
151  enum {
159  } type;
160  double value; // is sign in other types
161  union {
163  double (*func0)(double);
164  double (*func1)(void *, double);
165  double (*func2)(void *, double, double);
166  } a;
167  struct AVExpr *param[3];
168  double *var;
169 };
170 
171 static double etime(double v)
172 {
173  return av_gettime() * 0.000001;
174 }
175 
176 static double eval_expr(Parser *p, AVExpr *e)
177 {
178  switch (e->type) {
179  case e_value: return e->value;
180  case e_const: return e->value * p->const_values[e->a.const_index];
181  case e_func0: return e->value * e->a.func0(eval_expr(p, e->param[0]));
182  case e_func1: return e->value * e->a.func1(p->opaque, eval_expr(p, e->param[0]));
183  case e_func2: return e->value * e->a.func2(p->opaque, eval_expr(p, e->param[0]), eval_expr(p, e->param[1]));
184  case e_squish: return 1/(1+exp(4*eval_expr(p, e->param[0])));
185  case e_gauss: { double d = eval_expr(p, e->param[0]); return exp(-d*d/2)/sqrt(2*M_PI); }
186  case e_ld: return e->value * p->var[av_clip(eval_expr(p, e->param[0]), 0, VARS-1)];
187  case e_isnan: return e->value * !!isnan(eval_expr(p, e->param[0]));
188  case e_isinf: return e->value * !!isinf(eval_expr(p, e->param[0]));
189  case e_floor: return e->value * floor(eval_expr(p, e->param[0]));
190  case e_ceil : return e->value * ceil (eval_expr(p, e->param[0]));
191  case e_trunc: return e->value * trunc(eval_expr(p, e->param[0]));
192  case e_sqrt: return e->value * sqrt (eval_expr(p, e->param[0]));
193  case e_not: return e->value * (eval_expr(p, e->param[0]) == 0);
194  case e_if: 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_ifnot: return e->value * (!eval_expr(p, e->param[0]) ? eval_expr(p, e->param[1]) :
197  e->param[2] ? eval_expr(p, e->param[2]) : 0);
198  case e_clip: {
199  double x = eval_expr(p, e->param[0]);
200  double min = eval_expr(p, e->param[1]), max = eval_expr(p, e->param[2]);
201  if (isnan(min) || isnan(max) || isnan(x) || min > max)
202  return NAN;
203  return e->value * av_clipd(eval_expr(p, e->param[0]), min, max);
204  }
205  case e_between: {
206  double d = eval_expr(p, e->param[0]);
207  return e->value * (d >= eval_expr(p, e->param[1]) &&
208  d <= eval_expr(p, e->param[2]));
209  }
210  case e_print: {
211  double x = eval_expr(p, e->param[0]);
212  int level = e->param[1] ? av_clip(eval_expr(p, e->param[1]), INT_MIN, INT_MAX) : AV_LOG_INFO;
213  av_log(p, level, "%f\n", x);
214  return x;
215  }
216  case e_random:{
217  int idx= av_clip(eval_expr(p, e->param[0]), 0, VARS-1);
218  uint64_t r= isnan(p->var[idx]) ? 0 : p->var[idx];
219  r= r*1664525+1013904223;
220  p->var[idx]= r;
221  return e->value * (r * (1.0/UINT64_MAX));
222  }
223  case e_while: {
224  double d = NAN;
225  while (eval_expr(p, e->param[0]))
226  d=eval_expr(p, e->param[1]);
227  return d;
228  }
229  case e_taylor: {
230  double t = 1, d = 0, v;
231  double x = eval_expr(p, e->param[1]);
232  int id = e->param[2] ? av_clip(eval_expr(p, e->param[2]), 0, VARS-1) : 0;
233  int i;
234  double var0 = p->var[id];
235  for(i=0; i<1000; i++) {
236  double ld = d;
237  p->var[id] = i;
238  v = eval_expr(p, e->param[0]);
239  d += t*v;
240  if(ld==d && v)
241  break;
242  t *= x / (i+1);
243  }
244  p->var[id] = var0;
245  return d;
246  }
247  case e_root: {
248  int i, j;
249  double low = -1, high = -1, v, low_v = -DBL_MAX, high_v = DBL_MAX;
250  double var0 = p->var[0];
251  double x_max = eval_expr(p, e->param[1]);
252  for(i=-1; i<1024; i++) {
253  if(i<255) {
254  p->var[0] = ff_reverse[i&255]*x_max/255;
255  } else {
256  p->var[0] = x_max*pow(0.9, i-255);
257  if (i&1) p->var[0] *= -1;
258  if (i&2) p->var[0] += low;
259  else p->var[0] += high;
260  }
261  v = eval_expr(p, e->param[0]);
262  if (v<=0 && v>low_v) {
263  low = p->var[0];
264  low_v = v;
265  }
266  if (v>=0 && v<high_v) {
267  high = p->var[0];
268  high_v = v;
269  }
270  if (low>=0 && high>=0){
271  for (j=0; j<1000; j++) {
272  p->var[0] = (low+high)*0.5;
273  if (low == p->var[0] || high == p->var[0])
274  break;
275  v = eval_expr(p, e->param[0]);
276  if (v<=0) low = p->var[0];
277  if (v>=0) high= p->var[0];
278  if (isnan(v)) {
279  low = high = v;
280  break;
281  }
282  }
283  break;
284  }
285  }
286  p->var[0] = var0;
287  return -low_v<high_v ? low : high;
288  }
289  default: {
290  double d = eval_expr(p, e->param[0]);
291  double d2 = eval_expr(p, e->param[1]);
292  switch (e->type) {
293  case e_mod: return e->value * (d - floor((!CONFIG_FTRAPV || d2) ? d / d2 : d * INFINITY) * d2);
294  case e_gcd: return e->value * av_gcd(d,d2);
295  case e_max: return e->value * (d > d2 ? d : d2);
296  case e_min: return e->value * (d < d2 ? d : d2);
297  case e_eq: return e->value * (d == d2 ? 1.0 : 0.0);
298  case e_gt: return e->value * (d > d2 ? 1.0 : 0.0);
299  case e_gte: return e->value * (d >= d2 ? 1.0 : 0.0);
300  case e_lt: return e->value * (d < d2 ? 1.0 : 0.0);
301  case e_lte: return e->value * (d <= d2 ? 1.0 : 0.0);
302  case e_pow: return e->value * pow(d, d2);
303  case e_mul: return e->value * (d * d2);
304  case e_div: return e->value * ((!CONFIG_FTRAPV || d2 ) ? (d / d2) : d * INFINITY);
305  case e_add: return e->value * (d + d2);
306  case e_last:return e->value * d2;
307  case e_st : return e->value * (p->var[av_clip(d, 0, VARS-1)]= d2);
308  case e_hypot:return e->value * hypot(d, d2);
309  case e_atan2:return e->value * atan2(d, d2);
310  case e_bitand: return isnan(d) || isnan(d2) ? NAN : e->value * ((long int)d & (long int)d2);
311  case e_bitor: return isnan(d) || isnan(d2) ? NAN : e->value * ((long int)d | (long int)d2);
312  }
313  }
314  }
315  return NAN;
316 }
317 
318 static int parse_expr(AVExpr **e, Parser *p);
319 
321 {
322  if (!e) return;
323  av_expr_free(e->param[0]);
324  av_expr_free(e->param[1]);
325  av_expr_free(e->param[2]);
326  av_freep(&e->var);
327  av_freep(&e);
328 }
329 
330 static int parse_primary(AVExpr **e, Parser *p)
331 {
332  AVExpr *d = av_mallocz(sizeof(AVExpr));
333  char *next = p->s, *s0 = p->s;
334  int ret, i;
335 
336  if (!d)
337  return AVERROR(ENOMEM);
338 
339  /* number */
340  d->value = av_strtod(p->s, &next);
341  if (next != p->s) {
342  d->type = e_value;
343  p->s= next;
344  *e = d;
345  return 0;
346  }
347  d->value = 1;
348 
349  /* named constants */
350  for (i=0; p->const_names && p->const_names[i]; i++) {
351  if (strmatch(p->s, p->const_names[i])) {
352  p->s+= strlen(p->const_names[i]);
353  d->type = e_const;
354  d->a.const_index = i;
355  *e = d;
356  return 0;
357  }
358  }
359  for (i = 0; i < FF_ARRAY_ELEMS(constants); i++) {
360  if (strmatch(p->s, constants[i].name)) {
361  p->s += strlen(constants[i].name);
362  d->type = e_value;
363  d->value = constants[i].value;
364  *e = d;
365  return 0;
366  }
367  }
368 
369  p->s= strchr(p->s, '(');
370  if (!p->s) {
371  av_log(p, AV_LOG_ERROR, "Undefined constant or missing '(' in '%s'\n", s0);
372  p->s= next;
373  av_expr_free(d);
374  return AVERROR(EINVAL);
375  }
376  p->s++; // "("
377  if (*next == '(') { // special case do-nothing
378  av_freep(&d);
379  if ((ret = parse_expr(&d, p)) < 0)
380  return ret;
381  if (p->s[0] != ')') {
382  av_log(p, AV_LOG_ERROR, "Missing ')' in '%s'\n", s0);
383  av_expr_free(d);
384  return AVERROR(EINVAL);
385  }
386  p->s++; // ")"
387  *e = d;
388  return 0;
389  }
390  if ((ret = parse_expr(&(d->param[0]), p)) < 0) {
391  av_expr_free(d);
392  return ret;
393  }
394  if (p->s[0]== ',') {
395  p->s++; // ","
396  parse_expr(&d->param[1], p);
397  }
398  if (p->s[0]== ',') {
399  p->s++; // ","
400  parse_expr(&d->param[2], p);
401  }
402  if (p->s[0] != ')') {
403  av_log(p, AV_LOG_ERROR, "Missing ')' or too many args in '%s'\n", s0);
404  av_expr_free(d);
405  return AVERROR(EINVAL);
406  }
407  p->s++; // ")"
408 
409  d->type = e_func0;
410  if (strmatch(next, "sinh" )) d->a.func0 = sinh;
411  else if (strmatch(next, "cosh" )) d->a.func0 = cosh;
412  else if (strmatch(next, "tanh" )) d->a.func0 = tanh;
413  else if (strmatch(next, "sin" )) d->a.func0 = sin;
414  else if (strmatch(next, "cos" )) d->a.func0 = cos;
415  else if (strmatch(next, "tan" )) d->a.func0 = tan;
416  else if (strmatch(next, "atan" )) d->a.func0 = atan;
417  else if (strmatch(next, "asin" )) d->a.func0 = asin;
418  else if (strmatch(next, "acos" )) d->a.func0 = acos;
419  else if (strmatch(next, "exp" )) d->a.func0 = exp;
420  else if (strmatch(next, "log" )) d->a.func0 = log;
421  else if (strmatch(next, "abs" )) d->a.func0 = fabs;
422  else if (strmatch(next, "time" )) d->a.func0 = etime;
423  else if (strmatch(next, "squish")) d->type = e_squish;
424  else if (strmatch(next, "gauss" )) d->type = e_gauss;
425  else if (strmatch(next, "mod" )) d->type = e_mod;
426  else if (strmatch(next, "max" )) d->type = e_max;
427  else if (strmatch(next, "min" )) d->type = e_min;
428  else if (strmatch(next, "eq" )) d->type = e_eq;
429  else if (strmatch(next, "gte" )) d->type = e_gte;
430  else if (strmatch(next, "gt" )) d->type = e_gt;
431  else if (strmatch(next, "lte" )) d->type = e_lte;
432  else if (strmatch(next, "lt" )) d->type = e_lt;
433  else if (strmatch(next, "ld" )) d->type = e_ld;
434  else if (strmatch(next, "isnan" )) d->type = e_isnan;
435  else if (strmatch(next, "isinf" )) d->type = e_isinf;
436  else if (strmatch(next, "st" )) d->type = e_st;
437  else if (strmatch(next, "while" )) d->type = e_while;
438  else if (strmatch(next, "taylor")) d->type = e_taylor;
439  else if (strmatch(next, "root" )) d->type = e_root;
440  else if (strmatch(next, "floor" )) d->type = e_floor;
441  else if (strmatch(next, "ceil" )) d->type = e_ceil;
442  else if (strmatch(next, "trunc" )) d->type = e_trunc;
443  else if (strmatch(next, "sqrt" )) d->type = e_sqrt;
444  else if (strmatch(next, "not" )) d->type = e_not;
445  else if (strmatch(next, "pow" )) d->type = e_pow;
446  else if (strmatch(next, "print" )) d->type = e_print;
447  else if (strmatch(next, "random")) d->type = e_random;
448  else if (strmatch(next, "hypot" )) d->type = e_hypot;
449  else if (strmatch(next, "gcd" )) d->type = e_gcd;
450  else if (strmatch(next, "if" )) d->type = e_if;
451  else if (strmatch(next, "ifnot" )) d->type = e_ifnot;
452  else if (strmatch(next, "bitand")) d->type = e_bitand;
453  else if (strmatch(next, "bitor" )) d->type = e_bitor;
454  else if (strmatch(next, "between"))d->type = e_between;
455  else if (strmatch(next, "clip" )) d->type = e_clip;
456  else if (strmatch(next, "atan2" )) d->type = e_atan2;
457  else {
458  for (i=0; p->func1_names && p->func1_names[i]; i++) {
459  if (strmatch(next, p->func1_names[i])) {
460  d->a.func1 = p->funcs1[i];
461  d->type = e_func1;
462  *e = d;
463  return 0;
464  }
465  }
466 
467  for (i=0; p->func2_names && p->func2_names[i]; i++) {
468  if (strmatch(next, p->func2_names[i])) {
469  d->a.func2 = p->funcs2[i];
470  d->type = e_func2;
471  *e = d;
472  return 0;
473  }
474  }
475 
476  av_log(p, AV_LOG_ERROR, "Unknown function in '%s'\n", s0);
477  av_expr_free(d);
478  return AVERROR(EINVAL);
479  }
480 
481  *e = d;
482  return 0;
483 }
484 
485 static AVExpr *make_eval_expr(int type, int value, AVExpr *p0, AVExpr *p1)
486 {
487  AVExpr *e = av_mallocz(sizeof(AVExpr));
488  if (!e)
489  return NULL;
490  e->type =type ;
491  e->value =value ;
492  e->param[0] =p0 ;
493  e->param[1] =p1 ;
494  return e;
495 }
496 
497 static int parse_pow(AVExpr **e, Parser *p, int *sign)
498 {
499  *sign= (*p->s == '+') - (*p->s == '-');
500  p->s += *sign&1;
501  return parse_primary(e, p);
502 }
503 
504 static int parse_dB(AVExpr **e, Parser *p, int *sign)
505 {
506  /* do not filter out the negative sign when parsing a dB value.
507  for example, -3dB is not the same as -(3dB) */
508  if (*p->s == '-') {
509  char *next;
510  double av_unused ignored = strtod(p->s, &next);
511  if (next != p->s && next[0] == 'd' && next[1] == 'B') {
512  *sign = 0;
513  return parse_primary(e, p);
514  }
515  }
516  return parse_pow(e, p, sign);
517 }
518 
519 static int parse_factor(AVExpr **e, Parser *p)
520 {
521  int sign, sign2, ret;
522  AVExpr *e0, *e1, *e2;
523  if ((ret = parse_dB(&e0, p, &sign)) < 0)
524  return ret;
525  while(p->s[0]=='^'){
526  e1 = e0;
527  p->s++;
528  if ((ret = parse_dB(&e2, p, &sign2)) < 0) {
529  av_expr_free(e1);
530  return ret;
531  }
532  e0 = make_eval_expr(e_pow, 1, e1, e2);
533  if (!e0) {
534  av_expr_free(e1);
535  av_expr_free(e2);
536  return AVERROR(ENOMEM);
537  }
538  if (e0->param[1]) e0->param[1]->value *= (sign2|1);
539  }
540  if (e0) e0->value *= (sign|1);
541 
542  *e = e0;
543  return 0;
544 }
545 
546 static int parse_term(AVExpr **e, Parser *p)
547 {
548  int ret;
549  AVExpr *e0, *e1, *e2;
550  if ((ret = parse_factor(&e0, p)) < 0)
551  return ret;
552  while (p->s[0]=='*' || p->s[0]=='/') {
553  int c= *p->s++;
554  e1 = e0;
555  if ((ret = parse_factor(&e2, p)) < 0) {
556  av_expr_free(e1);
557  return ret;
558  }
559  e0 = make_eval_expr(c == '*' ? e_mul : e_div, 1, e1, e2);
560  if (!e0) {
561  av_expr_free(e1);
562  av_expr_free(e2);
563  return AVERROR(ENOMEM);
564  }
565  }
566  *e = e0;
567  return 0;
568 }
569 
570 static int parse_subexpr(AVExpr **e, Parser *p)
571 {
572  int ret;
573  AVExpr *e0, *e1, *e2;
574  if ((ret = parse_term(&e0, p)) < 0)
575  return ret;
576  while (*p->s == '+' || *p->s == '-') {
577  e1 = e0;
578  if ((ret = parse_term(&e2, p)) < 0) {
579  av_expr_free(e1);
580  return ret;
581  }
582  e0 = make_eval_expr(e_add, 1, e1, e2);
583  if (!e0) {
584  av_expr_free(e1);
585  av_expr_free(e2);
586  return AVERROR(ENOMEM);
587  }
588  };
589 
590  *e = e0;
591  return 0;
592 }
593 
594 static int parse_expr(AVExpr **e, Parser *p)
595 {
596  int ret;
597  AVExpr *e0, *e1, *e2;
598  if (p->stack_index <= 0) //protect against stack overflows
599  return AVERROR(EINVAL);
600  p->stack_index--;
601 
602  if ((ret = parse_subexpr(&e0, p)) < 0)
603  return ret;
604  while (*p->s == ';') {
605  p->s++;
606  e1 = e0;
607  if ((ret = parse_subexpr(&e2, p)) < 0) {
608  av_expr_free(e1);
609  return ret;
610  }
611  e0 = make_eval_expr(e_last, 1, e1, e2);
612  if (!e0) {
613  av_expr_free(e1);
614  av_expr_free(e2);
615  return AVERROR(ENOMEM);
616  }
617  };
618 
619  p->stack_index++;
620  *e = e0;
621  return 0;
622 }
623 
624 static int verify_expr(AVExpr *e)
625 {
626  if (!e) return 0;
627  switch (e->type) {
628  case e_value:
629  case e_const: return 1;
630  case e_func0:
631  case e_func1:
632  case e_squish:
633  case e_ld:
634  case e_gauss:
635  case e_isnan:
636  case e_isinf:
637  case e_floor:
638  case e_ceil:
639  case e_trunc:
640  case e_sqrt:
641  case e_not:
642  case e_random:
643  return verify_expr(e->param[0]) && !e->param[1];
644  case e_print:
645  return verify_expr(e->param[0])
646  && (!e->param[1] || verify_expr(e->param[1]));
647  case e_if:
648  case e_ifnot:
649  case e_taylor:
650  return verify_expr(e->param[0]) && verify_expr(e->param[1])
651  && (!e->param[2] || verify_expr(e->param[2]));
652  case e_between:
653  case e_clip:
654  return verify_expr(e->param[0]) &&
655  verify_expr(e->param[1]) &&
656  verify_expr(e->param[2]);
657  default: return verify_expr(e->param[0]) && verify_expr(e->param[1]) && !e->param[2];
658  }
659 }
660 
661 int av_expr_parse(AVExpr **expr, const char *s,
662  const char * const *const_names,
663  const char * const *func1_names, double (* const *funcs1)(void *, double),
664  const char * const *func2_names, double (* const *funcs2)(void *, double, double),
665  int log_offset, void *log_ctx)
666 {
667  Parser p = { 0 };
668  AVExpr *e = NULL;
669  char *w = av_malloc(strlen(s) + 1);
670  char *wp = w;
671  const char *s0 = s;
672  int ret = 0;
673 
674  if (!w)
675  return AVERROR(ENOMEM);
676 
677  while (*s)
678  if (!av_isspace(*s++)) *wp++ = s[-1];
679  *wp++ = 0;
680 
681  p.class = &eval_class;
682  p.stack_index=100;
683  p.s= w;
685  p.funcs1 = funcs1;
687  p.funcs2 = funcs2;
688  p.func2_names = func2_names;
689  p.log_offset = log_offset;
690  p.log_ctx = log_ctx;
691 
692  if ((ret = parse_expr(&e, &p)) < 0)
693  goto end;
694  if (*p.s) {
695  av_log(&p, AV_LOG_ERROR, "Invalid chars '%s' at the end of expression '%s'\n", p.s, s0);
696  ret = AVERROR(EINVAL);
697  goto end;
698  }
699  if (!verify_expr(e)) {
700  ret = AVERROR(EINVAL);
701  goto end;
702  }
703  e->var= av_mallocz(sizeof(double) *VARS);
704  if (!e->var) {
705  ret = AVERROR(ENOMEM);
706  goto end;
707  }
708  *expr = e;
709  e = NULL;
710 end:
711  av_expr_free(e);
712  av_free(w);
713  return ret;
714 }
715 
716 double av_expr_eval(AVExpr *e, const double *const_values, void *opaque)
717 {
718  Parser p = { 0 };
719  p.var= e->var;
720 
722  p.opaque = opaque;
723  return eval_expr(&p, e);
724 }
725 
726 int av_expr_parse_and_eval(double *d, const char *s,
727  const char * const *const_names, const double *const_values,
728  const char * const *func1_names, double (* const *funcs1)(void *, double),
729  const char * const *func2_names, double (* const *funcs2)(void *, double, double),
730  void *opaque, int log_offset, void *log_ctx)
731 {
732  AVExpr *e = NULL;
733  int ret = av_expr_parse(&e, s, const_names, func1_names, funcs1, func2_names, funcs2, log_offset, log_ctx);
734 
735  if (ret < 0) {
736  *d = NAN;
737  return ret;
738  }
739  *d = av_expr_eval(e, const_values, opaque);
740  av_expr_free(e);
741  return isnan(*d) ? AVERROR(EINVAL) : 0;
742 }
#define VARS
Definition: eval.c:56
static int verify_expr(AVExpr *e)
Definition: eval.c:624
const char *const * func1_names
Definition: eval.c:50
#define NULL
Definition: coverity.c:32
const char * s
Definition: avisynth_c.h:768
static const char *const func1_names[]
Definition: vf_rotate.c:195
#define isinf(x)
Definition: libm.h:317
static const struct @237 constants[]
#define LIBAVUTIL_VERSION_INT
Definition: version.h:86
const uint8_t ff_reverse[256]
Definition: reverse.c:23
union AVExpr::@239 a
const char * b
Definition: vf_curves.c:113
static av_const int av_isspace(int c)
Locale-independent conversion of ASCII isspace.
Definition: avstring.h:222
Convenience header that includes libavutil's core.
void * av_mallocz(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
Definition: mem.c:222
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:661
void * log_ctx
Definition: eval.c:55
Macro definitions for various function/variable attributes.
static int parse_dB(AVExpr **e, Parser *p, int *sign)
Definition: eval.c:504
#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:594
Definition: eval.c:43
static double(*const funcs1[])(void *, double)
Definition: vf_lut.c:195
Definition: eval.c:150
double strtod(const char *, char **)
const char *const * const_names
Definition: eval.c:48
double(* func1)(void *, double)
Definition: eval.c:164
static int parse_pow(AVExpr **e, Parser *p, int *sign)
Definition: eval.c:497
static int parse_factor(AVExpr **e, Parser *p)
Definition: eval.c:519
high precision timer, useful to profile code
#define av_log(a,...)
static const double const_values[]
Definition: eval.c:27
static int parse_subexpr(AVExpr **e, Parser *p)
Definition: eval.c:570
double(* func2)(void *, double, double)
Definition: eval.c:165
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:726
const double * const_values
Definition: eval.c:47
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:138
av_default_item_name
#define AVERROR(e)
Definition: error.h:43
int const_index
Definition: eval.c:162
#define M_E
Definition: mathematics.h:37
const char * r
Definition: vf_curves.c:111
#define s0
Definition: regdef.h:37
static int parse_term(AVExpr **e, Parser *p)
Definition: eval.c:546
int64_t av_gcd(int64_t a, int64_t b)
Compute the greatest common divisor of two integer operands.
Definition: mathematics.c:37
int8_t exp
Definition: eval.c:65
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:171
enum AVExpr::@238 type
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:140
static int parse_primary(AVExpr **e, Parser *p)
Definition: eval.c:330
double bin_val
Definition: eval.c:63
#define FF_ARRAY_ELEMS(a)
void * opaque
Definition: eval.c:53
#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:99
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:176
void av_expr_free(AVExpr *e)
Free a parsed expression previously created with av_expr_parse().
Definition: eval.c:320
double * var
Definition: eval.c:168
char * s
Definition: eval.c:46
GLint GLenum type
Definition: opengl_enc.c:105
double value
Definition: eval.c:91
Describe the class of an AVClass context structure.
Definition: log.h:67
static const AVClass eval_class
Definition: eval.c:60
double * var
Definition: eval.c:57
#define isnan(x)
Definition: libm.h:340
struct AVExpr * param[3]
Definition: eval.c:167
#define M_PHI
Definition: mathematics.h:49
double(*const funcs1)(void *, double a)
Definition: eval.c:49
const char *const * func2_names
Definition: eval.c:52
uint8_t level
Definition: svq3.c:207
internal math functions header
int
common internal and external API header
static double c[64]
int stack_index
Definition: eval.c:45
#define av_free(p)
double dec_val
Definition: eval.c:64
#define NAN
Definition: math.h:28
double(*const funcs2)(void *, double a, double b)
Definition: eval.c:51
double av_expr_eval(AVExpr *e, const double *const_values, void *opaque)
Evaluate a previously parsed expression.
Definition: eval.c:716
#define FF_QP2LAMBDA
factor to convert from H.263 QP to lambda
Definition: avutil.h:227
double(* func0)(double)
Definition: eval.c:163
static AVExpr * make_eval_expr(int type, int value, AVExpr *p0, AVExpr *p1)
Definition: eval.c:485
#define av_freep(p)
#define M_PI
Definition: mathematics.h:52
static const struct @236 si_prefixes['z'- 'E'+1]
int log_offset
Definition: eval.c:54
static const char *const const_names[]
Definition: eval.c:33
const char * name
Definition: eval.c:90
float min
enum AVCodecID id
#define av_unused
Definition: attributes.h:125
double value
Definition: eval.c:160
simple arithmetic expression evaluator
const char * name
Definition: opengl_enc.c:103