FFmpeg: libavutil/eval.c Source File

FFmpeg
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;
45   int stack_index;
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;
54   int log_offset;
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,
166  } type;
167   double value; // is sign in other types
168  union {
169   int const_index;
170   double (*func0)(double);
171   double (*func1)(void *, double);
172   double (*func2)(void *, double, double);
173  } a;
174   struct AVExpr *param[3];
175   double *var;
176 };
177 
178  static double etime(double v)
179 {
180  return av_gettime() * 0.000001;
181 }
182 
183  static double eval_expr(Parser *p, AVExpr *e)
184 {
185  switch (e->type) {
186  case e_value: return e->value;
187  case e_const: return e->value * p->const_values[e->a.const_index];
188  case e_func0: return e->value * e->a.func0(eval_expr(p, e->param[0]));
189  case e_func1: return e->value * e->a.func1(p->opaque, eval_expr(p, e->param[0]));
190  case e_func2: return e->value * e->a.func2(p->opaque, eval_expr(p, e->param[0]), eval_expr(p, e->param[1]));
191  case e_squish: return 1/(1+exp(4*eval_expr(p, e->param[0])));
192  case e_gauss: { double d = eval_expr(p, e->param[0]); return exp(-d*d/2)/sqrt(2*M_PI); }
193  case e_ld: return e->value * p->var[av_clip(eval_expr(p, e->param[0]), 0, VARS-1)];
194  case e_isnan: return e->value * !!isnan(eval_expr(p, e->param[0]));
195  case e_isinf: return e->value * !!isinf(eval_expr(p, e->param[0]));
196  case e_floor: return e->value * floor(eval_expr(p, e->param[0]));
197  case e_ceil : return e->value * ceil (eval_expr(p, e->param[0]));
198  case e_trunc: return e->value * trunc(eval_expr(p, e->param[0]));
199  case e_round: return e->value * round(eval_expr(p, e->param[0]));
200  case e_sqrt: return e->value * sqrt (eval_expr(p, e->param[0]));
201  case e_not: return e->value * (eval_expr(p, e->param[0]) == 0);
202  case e_if: return e->value * (eval_expr(p, e->param[0]) ? eval_expr(p, e->param[1]) :
203  e->param[2] ? eval_expr(p, e->param[2]) : 0);
204  case e_ifnot: 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_clip: {
207  double x = eval_expr(p, e->param[0]);
208  double min = eval_expr(p, e->param[1]), max = eval_expr(p, e->param[2]);
209  if (isnan(min) || isnan(max) || isnan(x) || min > max)
210  return NAN;
211  return e->value * av_clipd(eval_expr(p, e->param[0]), min, max);
212  }
213  case e_between: {
214  double d = eval_expr(p, e->param[0]);
215  return e->value * (d >= eval_expr(p, e->param[1]) &&
216  d <= eval_expr(p, e->param[2]));
217  }
218  case e_lerp: {
219  double v0 = eval_expr(p, e->param[0]);
220  double v1 = eval_expr(p, e->param[1]);
221  double f = eval_expr(p, e->param[2]);
222  return v0 + (v1 - v0) * f;
223  }
224  case e_print: {
225  double x = eval_expr(p, e->param[0]);
226  int level = e->param[1] ? av_clip(eval_expr(p, e->param[1]), INT_MIN, INT_MAX) : AV_LOG_INFO;
227  av_log(p, level, "%f\n", x);
228  return x;
229  }
230  case e_random:{
231  int idx= av_clip(eval_expr(p, e->param[0]), 0, VARS-1);
232  uint64_t r= isnan(p->var[idx]) ? 0 : p->var[idx];
233  r= r*1664525+1013904223;
234  p->var[idx]= r;
235  return e->value * (r * (1.0/UINT64_MAX));
236  }
237  case e_while: {
238  double d = NAN;
239  while (eval_expr(p, e->param[0]))
240  d=eval_expr(p, e->param[1]);
241  return d;
242  }
243  case e_taylor: {
244  double t = 1, d = 0, v;
245  double x = eval_expr(p, e->param[1]);
246  int id = e->param[2] ? av_clip(eval_expr(p, e->param[2]), 0, VARS-1) : 0;
247  int i;
248  double var0 = p->var[id];
249  for(i=0; i<1000; i++) {
250  double ld = d;
251  p->var[id] = i;
252  v = eval_expr(p, e->param[0]);
253  d += t*v;
254  if(ld==d && v)
255  break;
256  t *= x / (i+1);
257  }
258  p->var[id] = var0;
259  return d;
260  }
261  case e_root: {
262  int i, j;
263  double low = -1, high = -1, v, low_v = -DBL_MAX, high_v = DBL_MAX;
264  double var0 = p->var[0];
265  double x_max = eval_expr(p, e->param[1]);
266  for(i=-1; i<1024; i++) {
267  if(i<255) {
268  p->var[0] = ff_reverse[i&255]*x_max/255;
269  } else {
270  p->var[0] = x_max*pow(0.9, i-255);
271  if (i&1) p->var[0] *= -1;
272  if (i&2) p->var[0] += low;
273  else p->var[0] += high;
274  }
275  v = eval_expr(p, e->param[0]);
276  if (v<=0 && v>low_v) {
277  low = p->var[0];
278  low_v = v;
279  }
280  if (v>=0 && v<high_v) {
281  high = p->var[0];
282  high_v = v;
283  }
284  if (low>=0 && high>=0){
285  for (j=0; j<1000; j++) {
286  p->var[0] = (low+high)*0.5;
287  if (low == p->var[0] || high == p->var[0])
288  break;
289  v = eval_expr(p, e->param[0]);
290  if (v<=0) low = p->var[0];
291  if (v>=0) high= p->var[0];
292  if (isnan(v)) {
293  low = high = v;
294  break;
295  }
296  }
297  break;
298  }
299  }
300  p->var[0] = var0;
301  return -low_v<high_v ? low : high;
302  }
303  default: {
304  double d = eval_expr(p, e->param[0]);
305  double d2 = eval_expr(p, e->param[1]);
306  switch (e->type) {
307  case e_mod: return e->value * (d - floor((!CONFIG_FTRAPV || d2) ? d / d2 : d * INFINITY) * d2);
308  case e_gcd: return e->value * av_gcd(d,d2);
309  case e_max: return e->value * (d > d2 ? d : d2);
310  case e_min: return e->value * (d < d2 ? d : d2);
311  case e_eq: return e->value * (d == d2 ? 1.0 : 0.0);
312  case e_gt: return e->value * (d > d2 ? 1.0 : 0.0);
313  case e_gte: return e->value * (d >= d2 ? 1.0 : 0.0);
314  case e_lt: return e->value * (d < d2 ? 1.0 : 0.0);
315  case e_lte: return e->value * (d <= d2 ? 1.0 : 0.0);
316  case e_pow: return e->value * pow(d, d2);
317  case e_mul: return e->value * (d * d2);
318  case e_div: return e->value * ((!CONFIG_FTRAPV || d2 ) ? (d / d2) : d * INFINITY);
319  case e_add: return e->value * (d + d2);
320  case e_last:return e->value * d2;
321  case e_st : return e->value * (p->var[av_clip(d, 0, VARS-1)]= d2);
322  case e_hypot:return e->value * hypot(d, d2);
323  case e_atan2:return e->value * atan2(d, d2);
324  case e_bitand: return isnan(d) || isnan(d2) ? NAN : e->value * ((long int)d & (long int)d2);
325  case e_bitor: return isnan(d) || isnan(d2) ? NAN : e->value * ((long int)d | (long int)d2);
326  }
327  }
328  }
329  return NAN;
330 }
331 
332 static int parse_expr(AVExpr **e, Parser *p);
333 
334  void av_expr_free(AVExpr *e)
335 {
336  if (!e) return;
337  av_expr_free(e->param[0]);
338  av_expr_free(e->param[1]);
339  av_expr_free(e->param[2]);
340  av_freep(&e->var);
341  av_freep(&e);
342 }
343 
344  static int parse_primary(AVExpr **e, Parser *p)
345 {
346  AVExpr *d = av_mallocz(sizeof(AVExpr));
347  char *next = p->s, *s0 = p->s;
348  int ret, i;
349 
350  if (!d)
351  return AVERROR(ENOMEM);
352 
353  /* number */
354  d->value = av_strtod(p->s, &next);
355  if (next != p->s) {
356  d->type = e_value;
357  p->s= next;
358  *e = d;
359  return 0;
360  }
361  d->value = 1;
362 
363  /* named constants */
364  for (i=0; p->const_names && p->const_names[i]; i++) {
365  if (strmatch(p->s, p->const_names[i])) {
366  p->s+= strlen(p->const_names[i]);
367  d->type = e_const;
368  d->a.const_index = i;
369  *e = d;
370  return 0;
371  }
372  }
373  for (i = 0; i < FF_ARRAY_ELEMS(constants); i++) {
374  if (strmatch(p->s, constants[i].name)) {
375  p->s += strlen(constants[i].name);
376  d->type = e_value;
377  d->value = constants[i].value;
378  *e = d;
379  return 0;
380  }
381  }
382 
383  p->s= strchr(p->s, '(');
384  if (!p->s) {
385  av_log(p, AV_LOG_ERROR, "Undefined constant or missing '(' in '%s'\n", s0);
386  p->s= next;
387  av_expr_free(d);
388  return AVERROR(EINVAL);
389  }
390  p->s++; // "("
391  if (*next == '(') { // special case do-nothing
392  av_freep(&d);
393  if ((ret = parse_expr(&d, p)) < 0)
394  return ret;
395  if (p->s[0] != ')') {
396  av_log(p, AV_LOG_ERROR, "Missing ')' in '%s'\n", s0);
397  av_expr_free(d);
398  return AVERROR(EINVAL);
399  }
400  p->s++; // ")"
401  *e = d;
402  return 0;
403  }
404  if ((ret = parse_expr(&(d->param[0]), p)) < 0) {
405  av_expr_free(d);
406  return ret;
407  }
408  if (p->s[0]== ',') {
409  p->s++; // ","
410  parse_expr(&d->param[1], p);
411  }
412  if (p->s[0]== ',') {
413  p->s++; // ","
414  parse_expr(&d->param[2], p);
415  }
416  if (p->s[0] != ')') {
417  av_log(p, AV_LOG_ERROR, "Missing ')' or too many args in '%s'\n", s0);
418  av_expr_free(d);
419  return AVERROR(EINVAL);
420  }
421  p->s++; // ")"
422 
423  d->type = e_func0;
424  if (strmatch(next, "sinh" )) d->a.func0 = sinh;
425  else if (strmatch(next, "cosh" )) d->a.func0 = cosh;
426  else if (strmatch(next, "tanh" )) d->a.func0 = tanh;
427  else if (strmatch(next, "sin" )) d->a.func0 = sin;
428  else if (strmatch(next, "cos" )) d->a.func0 = cos;
429  else if (strmatch(next, "tan" )) d->a.func0 = tan;
430  else if (strmatch(next, "atan" )) d->a.func0 = atan;
431  else if (strmatch(next, "asin" )) d->a.func0 = asin;
432  else if (strmatch(next, "acos" )) d->a.func0 = acos;
433  else if (strmatch(next, "exp" )) d->a.func0 = exp;
434  else if (strmatch(next, "log" )) d->a.func0 = log;
435  else if (strmatch(next, "abs" )) d->a.func0 = fabs;
436  else if (strmatch(next, "time" )) d->a.func0 = etime;
437  else if (strmatch(next, "squish")) d->type = e_squish;
438  else if (strmatch(next, "gauss" )) d->type = e_gauss;
439  else if (strmatch(next, "mod" )) d->type = e_mod;
440  else if (strmatch(next, "max" )) d->type = e_max;
441  else if (strmatch(next, "min" )) d->type = e_min;
442  else if (strmatch(next, "eq" )) d->type = e_eq;
443  else if (strmatch(next, "gte" )) d->type = e_gte;
444  else if (strmatch(next, "gt" )) d->type = e_gt;
445  else if (strmatch(next, "lte" )) d->type = e_lte;
446  else if (strmatch(next, "lt" )) d->type = e_lt;
447  else if (strmatch(next, "ld" )) d->type = e_ld;
448  else if (strmatch(next, "isnan" )) d->type = e_isnan;
449  else if (strmatch(next, "isinf" )) d->type = e_isinf;
450  else if (strmatch(next, "st" )) d->type = e_st;
451  else if (strmatch(next, "while" )) d->type = e_while;
452  else if (strmatch(next, "taylor")) d->type = e_taylor;
453  else if (strmatch(next, "root" )) d->type = e_root;
454  else if (strmatch(next, "floor" )) d->type = e_floor;
455  else if (strmatch(next, "ceil" )) d->type = e_ceil;
456  else if (strmatch(next, "trunc" )) d->type = e_trunc;
457  else if (strmatch(next, "round" )) d->type = e_round;
458  else if (strmatch(next, "sqrt" )) d->type = e_sqrt;
459  else if (strmatch(next, "not" )) d->type = e_not;
460  else if (strmatch(next, "pow" )) d->type = e_pow;
461  else if (strmatch(next, "print" )) d->type = e_print;
462  else if (strmatch(next, "random")) d->type = e_random;
463  else if (strmatch(next, "hypot" )) d->type = e_hypot;
464  else if (strmatch(next, "gcd" )) d->type = e_gcd;
465  else if (strmatch(next, "if" )) d->type = e_if;
466  else if (strmatch(next, "ifnot" )) d->type = e_ifnot;
467  else if (strmatch(next, "bitand")) d->type = e_bitand;
468  else if (strmatch(next, "bitor" )) d->type = e_bitor;
469  else if (strmatch(next, "between"))d->type = e_between;
470  else if (strmatch(next, "clip" )) d->type = e_clip;
471  else if (strmatch(next, "atan2" )) d->type = e_atan2;
472  else if (strmatch(next, "lerp" )) d->type = e_lerp;
473  else {
474  for (i=0; p->func1_names && p->func1_names[i]; i++) {
475  if (strmatch(next, p->func1_names[i])) {
476  d->a.func1 = p->funcs1[i];
477  d->type = e_func1;
478  *e = d;
479  return 0;
480  }
481  }
482 
483  for (i=0; p->func2_names && p->func2_names[i]; i++) {
484  if (strmatch(next, p->func2_names[i])) {
485  d->a.func2 = p->funcs2[i];
486  d->type = e_func2;
487  *e = d;
488  return 0;
489  }
490  }
491 
492  av_log(p, AV_LOG_ERROR, "Unknown function in '%s'\n", s0);
493  av_expr_free(d);
494  return AVERROR(EINVAL);
495  }
496 
497  *e = d;
498  return 0;
499 }
500 
501  static AVExpr *make_eval_expr(int type, int value, AVExpr *p0, AVExpr *p1)
502 {
503  AVExpr *e = av_mallocz(sizeof(AVExpr));
504  if (!e)
505  return NULL;
506  e->type =type ;
507  e->value =value ;
508  e->param[0] =p0 ;
509  e->param[1] =p1 ;
510  return e;
511 }
512 
513  static int parse_pow(AVExpr **e, Parser *p, int *sign)
514 {
515  *sign= (*p->s == '+') - (*p->s == '-');
516  p->s += *sign&1;
517  return parse_primary(e, p);
518 }
519 
520  static int parse_dB(AVExpr **e, Parser *p, int *sign)
521 {
522  /* do not filter out the negative sign when parsing a dB value.
523  for example, -3dB is not the same as -(3dB) */
524  if (*p->s == '-') {
525  char *next;
526  double av_unused ignored = strtod(p->s, &next);
527  if (next != p->s && next[0] == 'd' && next[1] == 'B') {
528  *sign = 0;
529  return parse_primary(e, p);
530  }
531  }
532  return parse_pow(e, p, sign);
533 }
534 
535  static int parse_factor(AVExpr **e, Parser *p)
536 {
537  int sign, sign2, ret;
538  AVExpr *e0, *e1, *e2;
539  if ((ret = parse_dB(&e0, p, &sign)) < 0)
540  return ret;
541  while(p->s[0]=='^'){
542  e1 = e0;
543  p->s++;
544  if ((ret = parse_dB(&e2, p, &sign2)) < 0) {
545  av_expr_free(e1);
546  return ret;
547  }
548  e0 = make_eval_expr(e_pow, 1, e1, e2);
549  if (!e0) {
550  av_expr_free(e1);
551  av_expr_free(e2);
552  return AVERROR(ENOMEM);
553  }
554  if (e0->param[1]) e0->param[1]->value *= (sign2|1);
555  }
556  if (e0) e0->value *= (sign|1);
557 
558  *e = e0;
559  return 0;
560 }
561 
562  static int parse_term(AVExpr **e, Parser *p)
563 {
564  int ret;
565  AVExpr *e0, *e1, *e2;
566  if ((ret = parse_factor(&e0, p)) < 0)
567  return ret;
568  while (p->s[0]=='*' || p->s[0]=='/') {
569  int c= *p->s++;
570  e1 = e0;
571  if ((ret = parse_factor(&e2, p)) < 0) {
572  av_expr_free(e1);
573  return ret;
574  }
575  e0 = make_eval_expr(c == '*' ? e_mul : e_div, 1, e1, e2);
576  if (!e0) {
577  av_expr_free(e1);
578  av_expr_free(e2);
579  return AVERROR(ENOMEM);
580  }
581  }
582  *e = e0;
583  return 0;
584 }
585 
586  static int parse_subexpr(AVExpr **e, Parser *p)
587 {
588  int ret;
589  AVExpr *e0, *e1, *e2;
590  if ((ret = parse_term(&e0, p)) < 0)
591  return ret;
592  while (*p->s == '+' || *p->s == '-') {
593  e1 = e0;
594  if ((ret = parse_term(&e2, p)) < 0) {
595  av_expr_free(e1);
596  return ret;
597  }
598  e0 = make_eval_expr(e_add, 1, e1, e2);
599  if (!e0) {
600  av_expr_free(e1);
601  av_expr_free(e2);
602  return AVERROR(ENOMEM);
603  }
604  };
605 
606  *e = e0;
607  return 0;
608 }
609 
610  static int parse_expr(AVExpr **e, Parser *p)
611 {
612  int ret;
613  AVExpr *e0, *e1, *e2;
614  if (p->stack_index <= 0) //protect against stack overflows
615  return AVERROR(EINVAL);
616  p->stack_index--;
617 
618  if ((ret = parse_subexpr(&e0, p)) < 0)
619  return ret;
620  while (*p->s == ';') {
621  p->s++;
622  e1 = e0;
623  if ((ret = parse_subexpr(&e2, p)) < 0) {
624  av_expr_free(e1);
625  return ret;
626  }
627  e0 = make_eval_expr(e_last, 1, e1, e2);
628  if (!e0) {
629  av_expr_free(e1);
630  av_expr_free(e2);
631  return AVERROR(ENOMEM);
632  }
633  };
634 
635  p->stack_index++;
636  *e = e0;
637  return 0;
638 }
639 
640  static int verify_expr(AVExpr *e)
641 {
642  if (!e) return 0;
643  switch (e->type) {
644  case e_value:
645  case e_const: return 1;
646  case e_func0:
647  case e_func1:
648  case e_squish:
649  case e_ld:
650  case e_gauss:
651  case e_isnan:
652  case e_isinf:
653  case e_floor:
654  case e_ceil:
655  case e_trunc:
656  case e_round:
657  case e_sqrt:
658  case e_not:
659  case e_random:
660  return verify_expr(e->param[0]) && !e->param[1];
661  case e_print:
662  return verify_expr(e->param[0])
663  && (!e->param[1] || verify_expr(e->param[1]));
664  case e_if:
665  case e_ifnot:
666  case e_taylor:
667  return verify_expr(e->param[0]) && verify_expr(e->param[1])
668  && (!e->param[2] || verify_expr(e->param[2]));
669  case e_between:
670  case e_clip:
671  case e_lerp:
672  return verify_expr(e->param[0]) &&
673  verify_expr(e->param[1]) &&
674  verify_expr(e->param[2]);
675  default: return verify_expr(e->param[0]) && verify_expr(e->param[1]) && !e->param[2];
676  }
677 }
678 
679  int av_expr_parse(AVExpr **expr, const char *s,
680  const char * const *const_names,
681  const char * const *func1_names, double (* const *funcs1)(void *, double),
682  const char * const *func2_names, double (* const *funcs2)(void *, double, double),
683  int log_offset, void *log_ctx)
684 {
685  Parser p = { 0 };
686  AVExpr *e = NULL;
687  char *w = av_malloc(strlen(s) + 1);
688  char *wp = w;
689  const char *s0 = s;
690  int ret = 0;
691 
692  if (!w)
693  return AVERROR(ENOMEM);
694 
695  while (*s)
696  if (!av_isspace(*s++)) *wp++ = s[-1];
697  *wp++ = 0;
698 
699  p.class = &eval_class;
700  p.stack_index=100;
701  p.s= w;
702  p.const_names = const_names;
703  p.funcs1 = funcs1;
704  p.func1_names = func1_names;
705  p.funcs2 = funcs2;
706  p.func2_names = func2_names;
707  p.log_offset = log_offset;
708  p.log_ctx = log_ctx;
709 
710  if ((ret = parse_expr(&e, &p)) < 0)
711  goto end;
712  if (*p.s) {
713  av_log(&p, AV_LOG_ERROR, "Invalid chars '%s' at the end of expression '%s'\n", p.s, s0);
714  ret = AVERROR(EINVAL);
715  goto end;
716  }
717  if (!verify_expr(e)) {
718  ret = AVERROR(EINVAL);
719  goto end;
720  }
721  e->var= av_mallocz(sizeof(double) *VARS);
722  if (!e->var) {
723  ret = AVERROR(ENOMEM);
724  goto end;
725  }
726  *expr = e;
727  e = NULL;
728 end:
729  av_expr_free(e);
730  av_free(w);
731  return ret;
732 }
733 
734  double av_expr_eval(AVExpr *e, const double *const_values, void *opaque)
735 {
736  Parser p = { 0 };
737  p.var= e->var;
738 
739  p.const_values = const_values;
740  p.opaque = opaque;
741  return eval_expr(&p, e);
742 }
743 
744  int av_expr_parse_and_eval(double *d, const char *s,
745  const char * const *const_names, const double *const_values,
746  const char * const *func1_names, double (* const *funcs1)(void *, double),
747  const char * const *func2_names, double (* const *funcs2)(void *, double, double),
748  void *opaque, int log_offset, void *log_ctx)
749 {
750  AVExpr *e = NULL;
751  int ret = av_expr_parse(&e, s, const_names, func1_names, funcs1, func2_names, funcs2, log_offset, log_ctx);
752 
753  if (ret < 0) {
754  *d = NAN;
755  return ret;
756  }
757  *d = av_expr_eval(e, const_values, opaque);
758  av_expr_free(e);
759  return isnan(*d) ? AVERROR(EINVAL) : 0;
760 }
VARS
#define VARS
Definition: eval.c:56
verify_expr
static int verify_expr(AVExpr *e)
Definition: eval.c:640
Parser::func1_names
const char *const * func1_names
Definition: eval.c:50
NULL
#define NULL
Definition: coverity.c:32
s
const char * s
Definition: avisynth_c.h:768
func1_names
static const char *const func1_names[]
Definition: vf_rotate.c:195
isinf
#define isinf(x)
Definition: libm.h:317
LIBAVUTIL_VERSION_INT
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
si_prefixes
static const struct @243 si_prefixes['z'- 'E'+1]
ff_reverse
const uint8_t ff_reverse[256]
Definition: reverse.c:23
b
const char * b
Definition: vf_curves.c:113
av_default_item_name
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:191
av_isspace
static av_const int av_isspace(int c)
Locale-independent conversion of ASCII isspace.
Definition: avstring.h:222
avutil.h
Convenience header that includes libavutil's core.
av_mallocz
void * av_mallocz(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
Definition: mem.c:236
av_expr_parse
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:679
v0
GLfloat v0
Definition: opengl_enc.c:107
Parser::log_ctx
void * log_ctx
Definition: eval.c:55
attributes.h
Macro definitions for various function/variable attributes.
AVClass::class_name
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
parse_dB
static int parse_dB(AVExpr **e, Parser *p, int *sign)
Definition: eval.c:520
av_malloc
#define av_malloc(s)
Definition: tableprint_vlc.h:31
end
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:90
parse_expr
static int parse_expr(AVExpr **e, Parser *p)
Definition: eval.c:610
Parser
Definition: eval.c:43
funcs1
static double(*const funcs1[])(void *, double)
Definition: vf_lut.c:200
AVExpr
Definition: eval.c:157
strtod
double strtod(const char *, char **)
Parser::const_names
const char *const * const_names
Definition: eval.c:48
AVExpr::func1
double(* func1)(void *, double)
Definition: eval.c:171
parse_pow
static int parse_pow(AVExpr **e, Parser *p, int *sign)
Definition: eval.c:513
parse_factor
static int parse_factor(AVExpr **e, Parser *p)
Definition: eval.c:535
timer.h
high precision timer, useful to profile code
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
const_values
static const double const_values[]
Definition: eval.c:28
parse_subexpr
static int parse_subexpr(AVExpr **e, Parser *p)
Definition: eval.c:586
AVExpr::func2
double(* func2)(void *, double, double)
Definition: eval.c:172
av_expr_parse_and_eval
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:744
Parser::const_values
const double * const_values
Definition: eval.c:47
ff_exp10
static av_always_inline double ff_exp10(double x)
Compute 10^x for floating point values.
Definition: ffmath.h:42
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
IS_IDENTIFIER_CHAR
#define IS_IDENTIFIER_CHAR(c)
Definition: eval.c:145
AVERROR
#define AVERROR(e)
Definition: error.h:43
AVExpr::const_index
int const_index
Definition: eval.c:169
M_E
#define M_E
Definition: mathematics.h:37
r
const char * r
Definition: vf_curves.c:111
s0
#define s0
Definition: regdef.h:37
parse_term
static int parse_term(AVExpr **e, Parser *p)
Definition: eval.c:562
constants
static const struct @244 constants[]
av_gcd
int64_t av_gcd(int64_t a, int64_t b)
Compute the greatest common divisor of two integer operands.
Definition: mathematics.c:37
round
static av_always_inline av_const double round(double x)
Definition: libm.h:444
exp
int8_t exp
Definition: eval.c:72
internal.h
common internal API header
hypot
static av_const double hypot(double x, double y)
Definition: libm.h:366
etime
static double etime(double v)
Definition: eval.c:178
NAN
#define NAN
Definition: mathematics.h:64
AVExpr::a
union AVExpr::@246 a
AVExpr::type
enum AVExpr::@245 type
w
uint8_t w
Definition: llviddspenc.c:38
value
GLsizei GLboolean const GLfloat * value
Definition: opengl_enc.c:109
trunc
static av_always_inline av_const double trunc(double x)
Definition: libm.h:458
strmatch
static int strmatch(const char *s, const char *prefix)
Definition: eval.c:147
parse_primary
static int parse_primary(AVExpr **e, Parser *p)
Definition: eval.c:344
bin_val
double bin_val
Definition: eval.c:70
FF_ARRAY_ELEMS
#define FF_ARRAY_ELEMS(a)
Definition: sinewin_tablegen_template.c:36
Parser::opaque
void * opaque
Definition: eval.c:53
av_gettime
int64_t av_gettime(void)
Get the current time in microseconds.
Definition: time.c:39
av_strtod
double av_strtod(const char *numstr, char **tail)
Parse the string in numstr and return its value as a double.
Definition: eval.c:106
Parser::class
const AVClass * class
Definition: eval.c:44
AV_LOG_INFO
#define AV_LOG_INFO
Standard information.
Definition: log.h:187
eval_expr
static double eval_expr(Parser *p, AVExpr *e)
Definition: eval.c:183
av_expr_free
void av_expr_free(AVExpr *e)
Free a parsed expression previously created with av_expr_parse().
Definition: eval.c:334
AVExpr::var
double * var
Definition: eval.c:175
Parser::s
char * s
Definition: eval.c:46
type
GLint GLenum type
Definition: opengl_enc.c:105
value
double value
Definition: eval.c:98
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:67
eval_class
static const AVClass eval_class
Definition: eval.c:60
Parser::var
double * var
Definition: eval.c:57
isnan
#define isnan(x)
Definition: libm.h:340
AVExpr::param
struct AVExpr * param[3]
Definition: eval.c:174
M_PHI
#define M_PHI
Definition: mathematics.h:49
Parser::funcs1
double(*const funcs1)(void *, double a)
Definition: eval.c:49
Parser::func2_names
const char *const * func2_names
Definition: eval.c:52
level
uint8_t level
Definition: svq3.c:207
ffmath.h
internal math functions header
int
int
Definition: ffmpeg_filter.c:190
common.h
common internal and external API header
c
static double c[64]
Definition: vsrc_mptestsrc.c:87
Parser::stack_index
int stack_index
Definition: eval.c:45
av_free
#define av_free(p)
Definition: tableprint_vlc.h:34
dec_val
double dec_val
Definition: eval.c:71
Parser::funcs2
double(*const funcs2)(void *, double a, double b)
Definition: eval.c:51
av_expr_eval
double av_expr_eval(AVExpr *e, const double *const_values, void *opaque)
Evaluate a previously parsed expression.
Definition: eval.c:734
FF_QP2LAMBDA
#define FF_QP2LAMBDA
factor to convert from H.263 QP to lambda
Definition: avutil.h:227
AVExpr::func0
double(* func0)(double)
Definition: eval.c:170
make_eval_expr
static AVExpr * make_eval_expr(int type, int value, AVExpr *p0, AVExpr *p1)
Definition: eval.c:501
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:35
M_PI
#define M_PI
Definition: mathematics.h:52
Parser::log_offset
int log_offset
Definition: eval.c:54
const_names
static const char *const const_names[]
Definition: eval.c:34
name
const char * name
Definition: eval.c:97
INFINITY
#define INFINITY
Definition: mathematics.h:67
min
float min
Definition: vorbis_enc_data.h:456
id
enum AVCodecID id
Definition: extract_extradata_bsf.c:250
av_unused
#define av_unused
Definition: attributes.h:125
AVExpr::value
double value
Definition: eval.c:167
a
a
Definition: h264pred_template.c:468
eval.h
simple arithmetic expression evaluator
name
const char * name
Definition: opengl_enc.c:103
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