summaryrefslogtreecommitdiff
path: root/libavutil/eval.c
blob: 48f8e66ec6ce0ca6f314e386d092bafe0dd684a1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
/*
 * Copyright (c) 2002-2006 Michael Niedermayer <michaelni@gmx.at>
 * Copyright (c) 2006 Oded Shimon <ods15@ods15.dyndns.org>
 *
 * This file is part of Libav.
 *
 * Libav is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * Libav is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * simple arithmetic expression evaluator.
 *
 * see http://joe.hotchkiss.com/programming/eval/eval.html
 */

#include "attributes.h"
#include "avutil.h"
#include "common.h"
#include "eval.h"
#include "log.h"
#include "mathematics.h"
#include "avstring.h"

typedef struct Parser {
    const AVClass *class;
    int stack_index;
    char *s;
    const double *const_values;
    const char * const *const_names;          // NULL terminated
    double (* const *funcs1)(void *, double a);           // NULL terminated
    const char * const *func1_names;          // NULL terminated
    double (* const *funcs2)(void *, double a, double b); // NULL terminated
    const char * const *func2_names;          // NULL terminated
    void *opaque;
    int log_offset;
    void *log_ctx;
#define VARS 10
    double var[VARS];
} Parser;

static const AVClass class = { "Eval", av_default_item_name, NULL, LIBAVUTIL_VERSION_INT, offsetof(Parser,log_offset), offsetof(Parser,log_ctx) };

static const int8_t si_prefixes['z' - 'E' + 1] = {
    ['y'-'E']= -24,
    ['z'-'E']= -21,
    ['a'-'E']= -18,
    ['f'-'E']= -15,
    ['p'-'E']= -12,
    ['n'-'E']= - 9,
    ['u'-'E']= - 6,
    ['m'-'E']= - 3,
    ['c'-'E']= - 2,
    ['d'-'E']= - 1,
    ['h'-'E']=   2,
    ['k'-'E']=   3,
    ['K'-'E']=   3,
    ['M'-'E']=   6,
    ['G'-'E']=   9,
    ['T'-'E']=  12,
    ['P'-'E']=  15,
    ['E'-'E']=  18,
    ['Z'-'E']=  21,
    ['Y'-'E']=  24,
};

double av_strtod(const char *numstr, char **tail)
{
    double d;
    char *next;
    d = strtod(numstr, &next);
    /* if parsing succeeded, check for and interpret postfixes */
    if (next!=numstr) {
        if (next[0] == 'd' && next[1] == 'B') {
            /* treat dB as decibels instead of decibytes */
            d = pow(10, d / 20);
            next += 2;
        } else if (*next >= 'E' && *next <= 'z') {
            int e= si_prefixes[*next - 'E'];
            if (e) {
                if (next[1] == 'i') {
                    d*= pow( 2, e/0.3);
                    next+=2;
                } else {
                    d*= pow(10, e);
                    next++;
                }
            }
        }

        if (*next=='B') {
            d*=8;
            next++;
        }
    }
    /* if requested, fill in tail with the position after the last parsed
       character */
    if (tail)
        *tail = next;
    return d;
}

#define IS_IDENTIFIER_CHAR(c) ((c) - '0' <= 9U || (c) - 'a' <= 25U || (c) - 'A' <= 25U || (c) == '_')

static int strmatch(const char *s, const char *prefix)
{
    int i;
    for (i=0; prefix[i]; i++) {
        if (prefix[i] != s[i]) return 0;
    }
    /* return 1 only if the s identifier is terminated */
    return !IS_IDENTIFIER_CHAR(s[i]);
}

struct AVExpr {
    enum {
        e_value, e_const, e_func0, e_func1, e_func2,
        e_squish, e_gauss, e_ld, e_isnan, e_isinf,
        e_mod, e_max, e_min, e_eq, e_gt, e_gte,
        e_pow, e_mul, e_div, e_add,
        e_last, e_st, e_while, e_floor, e_ceil, e_trunc,
        e_sqrt, e_not,
    } type;
    double value; // is sign in other types
    union {
        int const_index;
        double (*func0)(double);
        double (*func1)(void *, double);
        double (*func2)(void *, double, double);
    } a;
    struct AVExpr *param[2];
};

static double eval_expr(Parser *p, AVExpr *e)
{
    switch (e->type) {
        case e_value:  return e->value;
        case e_const:  return e->value * p->const_values[e->a.const_index];
        case e_func0:  return e->value * e->a.func0(eval_expr(p, e->param[0]));
        case e_func1:  return e->value * e->a.func1(p->opaque, eval_expr(p, e->param[0]));
        case e_func2:  return e->value * e->a.func2(p->opaque, eval_expr(p, e->param[0]), eval_expr(p, e->param[1]));
        case e_squish: return 1/(1+exp(4*eval_expr(p, e->param[0])));
        case e_gauss: { double d = eval_expr(p, e->param[0]); return exp(-d*d/2)/sqrt(2*M_PI); }
        case e_ld:     return e->value * p->var[av_clip(eval_expr(p, e->param[0]), 0, VARS-1)];
        case e_isnan:  return e->value * !!isnan(eval_expr(p, e->param[0]));
        case e_isinf:  return e->value * !!isinf(eval_expr(p, e->param[0]));
        case e_floor:  return e->value * floor(eval_expr(p, e->param[0]));
        case e_ceil :  return e->value * ceil (eval_expr(p, e->param[0]));
        case e_trunc:  return e->value * trunc(eval_expr(p, e->param[0]));
        case e_sqrt:   return e->value * sqrt (eval_expr(p, e->param[0]));
        case e_not:    return e->value * eval_expr(p, e->param[0]) == 0;
        case e_while: {
            double d = NAN;
            while (eval_expr(p, e->param[0]))
                d=eval_expr(p, e->param[1]);
            return d;
        }
        default: {
            double d = eval_expr(p, e->param[0]);
            double d2 = eval_expr(p, e->param[1]);
            switch (e->type) {
                case e_mod: return e->value * (d - floor(d/d2)*d2);
                case e_max: return e->value * (d >  d2 ?   d : d2);
                case e_min: return e->value * (d <  d2 ?   d : d2);
                case e_eq:  return e->value * (d == d2 ? 1.0 : 0.0);
                case e_gt:  return e->value * (d >  d2 ? 1.0 : 0.0);
                case e_gte: return e->value * (d >= d2 ? 1.0 : 0.0);
                case e_pow: return e->value * pow(d, d2);
                case e_mul: return e->value * (d * d2);
                case e_div: return e->value * (d / d2);
                case e_add: return e->value * (d + d2);
                case e_last:return e->value * d2;
                case e_st : return e->value * (p->var[av_clip(d, 0, VARS-1)]= d2);
            }
        }
    }
    return NAN;
}

static int parse_expr(AVExpr **e, Parser *p);

void av_expr_free(AVExpr *e)
{
    if (!e) return;
    av_expr_free(e->param[0]);
    av_expr_free(e->param[1]);
    av_freep(&e);
}

static int parse_primary(AVExpr **e, Parser *p)
{
    AVExpr *d = av_mallocz(sizeof(AVExpr));
    char *next = p->s, *s0 = p->s;
    int ret, i;

    if (!d)
        return AVERROR(ENOMEM);

    /* number */
    d->value = av_strtod(p->s, &next);
    if (next != p->s) {
        d->type = e_value;
        p->s= next;
        *e = d;
        return 0;
    }
    d->value = 1;

    /* named constants */
    for (i=0; p->const_names && p->const_names[i]; i++) {
        if (strmatch(p->s, p->const_names[i])) {
            p->s+= strlen(p->const_names[i]);
            d->type = e_const;
            d->a.const_index = i;
            *e = d;
            return 0;
        }
    }

    p->s= strchr(p->s, '(');
    if (p->s==NULL) {
        av_log(p, AV_LOG_ERROR, "Undefined constant or missing '(' in '%s'\n", s0);
        p->s= next;
        av_expr_free(d);
        return AVERROR(EINVAL);
    }
    p->s++; // "("
    if (*next == '(') { // special case do-nothing
        av_freep(&d);
        if ((ret = parse_expr(&d, p)) < 0)
            return ret;
        if (p->s[0] != ')') {
            av_log(p, AV_LOG_ERROR, "Missing ')' in '%s'\n", s0);
            av_expr_free(d);
            return AVERROR(EINVAL);
        }
        p->s++; // ")"
        *e = d;
        return 0;
    }
    if ((ret = parse_expr(&(d->param[0]), p)) < 0) {
        av_expr_free(d);
        return ret;
    }
    if (p->s[0]== ',') {
        p->s++; // ","
        parse_expr(&d->param[1], p);
    }
    if (p->s[0] != ')') {
        av_log(p, AV_LOG_ERROR, "Missing ')' or too many args in '%s'\n", s0);
        av_expr_free(d);
        return AVERROR(EINVAL);
    }
    p->s++; // ")"

    d->type = e_func0;
         if (strmatch(next, "sinh"  )) d->a.func0 = sinh;
    else if (strmatch(next, "cosh"  )) d->a.func0 = cosh;
    else if (strmatch(next, "tanh"  )) d->a.func0 = tanh;
    else if (strmatch(next, "sin"   )) d->a.func0 = sin;
    else if (strmatch(next, "cos"   )) d->a.func0 = cos;
    else if (strmatch(next, "tan"   )) d->a.func0 = tan;
    else if (strmatch(next, "atan"  )) d->a.func0 = atan;
    else if (strmatch(next, "asin"  )) d->a.func0 = asin;
    else if (strmatch(next, "acos"  )) d->a.func0 = acos;
    else if (strmatch(next, "exp"   )) d->a.func0 = exp;
    else if (strmatch(next, "log"   )) d->a.func0 = log;
    else if (strmatch(next, "abs"   )) d->a.func0 = fabs;
    else if (strmatch(next, "squish")) d->type = e_squish;
    else if (strmatch(next, "gauss" )) d->type = e_gauss;
    else if (strmatch(next, "mod"   )) d->type = e_mod;
    else if (strmatch(next, "max"   )) d->type = e_max;
    else if (strmatch(next, "min"   )) d->type = e_min;
    else if (strmatch(next, "eq"    )) d->type = e_eq;
    else if (strmatch(next, "gte"   )) d->type = e_gte;
    else if (strmatch(next, "gt"    )) d->type = e_gt;
    else if (strmatch(next, "lte"   )) { AVExpr *tmp = d->param[1]; d->param[1] = d->param[0]; d->param[0] = tmp; d->type = e_gte; }
    else if (strmatch(next, "lt"    )) { AVExpr *tmp = d->param[1]; d->param[1] = d->param[0]; d->param[0] = tmp; d->type = e_gt; }
    else if (strmatch(next, "ld"    )) d->type = e_ld;
    else if (strmatch(next, "isnan" )) d->type = e_isnan;
    else if (strmatch(next, "isinf" )) d->type = e_isinf;
    else if (strmatch(next, "st"    )) d->type = e_st;
    else if (strmatch(next, "while" )) d->type = e_while;
    else if (strmatch(next, "floor" )) d->type = e_floor;
    else if (strmatch(next, "ceil"  )) d->type = e_ceil;
    else if (strmatch(next, "trunc" )) d->type = e_trunc;
    else if (strmatch(next, "sqrt"  )) d->type = e_sqrt;
    else if (strmatch(next, "not"   )) d->type = e_not;
    else {
        for (i=0; p->func1_names && p->func1_names[i]; i++) {
            if (strmatch(next, p->func1_names[i])) {
                d->a.func1 = p->funcs1[i];
                d->type = e_func1;
                *e = d;
                return 0;
            }
        }

        for (i=0; p->func2_names && p->func2_names[i]; i++) {
            if (strmatch(next, p->func2_names[i])) {
                d->a.func2 = p->funcs2[i];
                d->type = e_func2;
                *e = d;
                return 0;
            }
        }

        av_log(p, AV_LOG_ERROR, "Unknown function in '%s'\n", s0);
        av_expr_free(d);
        return AVERROR(EINVAL);
    }

    *e = d;
    return 0;
}

static AVExpr *new_eval_expr(int type, int value, AVExpr *p0, AVExpr *p1)
{
    AVExpr *e = av_mallocz(sizeof(AVExpr));
    if (!e)
        return NULL;
    e->type     =type   ;
    e->value    =value  ;
    e->param[0] =p0     ;
    e->param[1] =p1     ;
    return e;
}

static int parse_pow(AVExpr **e, Parser *p, int *sign)
{
    *sign= (*p->s == '+') - (*p->s == '-');
    p->s += *sign&1;
    return parse_primary(e, p);
}

static int parse_dB(AVExpr **e, Parser *p, int *sign)
{
    /* do not filter out the negative sign when parsing a dB value.
       for example, -3dB is not the same as -(3dB) */
    if (*p->s == '-') {
        char *next;
        double av_unused ignored = strtod(p->s, &next);
        if (next != p->s && next[0] == 'd' && next[1] == 'B') {
            *sign = 0;
            return parse_primary(e, p);
        }
    }
    return parse_pow(e, p, sign);
}

static int parse_factor(AVExpr **e, Parser *p)
{
    int sign, sign2, ret;
    AVExpr *e0, *e1, *e2;
    if ((ret = parse_dB(&e0, p, &sign)) < 0)
        return ret;
    while(p->s[0]=='^'){
        e1 = e0;
        p->s++;
        if ((ret = parse_dB(&e2, p, &sign2)) < 0) {
            av_expr_free(e1);
            return ret;
        }
        e0 = new_eval_expr(e_pow, 1, e1, e2);
        if (!e0) {
            av_expr_free(e1);
            av_expr_free(e2);
            return AVERROR(ENOMEM);
        }
        if (e0->param[1]) e0->param[1]->value *= (sign2|1);
    }
    if (e0) e0->value *= (sign|1);

    *e = e0;
    return 0;
}

static int parse_term(AVExpr **e, Parser *p)
{
    int ret;
    AVExpr *e0, *e1, *e2;
    if ((ret = parse_factor(&e0, p)) < 0)
        return ret;
    while (p->s[0]=='*' || p->s[0]=='/') {
        int c= *p->s++;
        e1 = e0;
        if ((ret = parse_factor(&e2, p)) < 0) {
            av_expr_free(e1);
            return ret;
        }
        e0 = new_eval_expr(c == '*' ? e_mul : e_div, 1, e1, e2);
        if (!e0) {
            av_expr_free(e1);
            av_expr_free(e2);
            return AVERROR(ENOMEM);
        }
    }
    *e = e0;
    return 0;
}

static int parse_subexpr(AVExpr **e, Parser *p)
{
    int ret;
    AVExpr *e0, *e1, *e2;
    if ((ret = parse_term(&e0, p)) < 0)
        return ret;
    while (*p->s == '+' || *p->s == '-') {
        e1 = e0;
        if ((ret = parse_term(&e2, p)) < 0) {
            av_expr_free(e1);
            return ret;
        }
        e0 = new_eval_expr(e_add, 1, e1, e2);
        if (!e0) {
            av_expr_free(e1);
            av_expr_free(e2);
            return AVERROR(ENOMEM);
        }
    };

    *e = e0;
    return 0;
}

static int parse_expr(AVExpr **e, Parser *p)
{
    int ret;
    AVExpr *e0, *e1, *e2;
    if (p->stack_index <= 0) //protect against stack overflows
        return AVERROR(EINVAL);
    p->stack_index--;

    if ((ret = parse_subexpr(&e0, p)) < 0)
        return ret;
    while (*p->s == ';') {
        p->s++;
        e1 = e0;
        if ((ret = parse_subexpr(&e2, p)) < 0) {
            av_expr_free(e1);
            return ret;
        }
        e0 = new_eval_expr(e_last, 1, e1, e2);
        if (!e0) {
            av_expr_free(e1);
            av_expr_free(e2);
            return AVERROR(ENOMEM);
        }
    };

    p->stack_index++;
    *e = e0;
    return 0;
}

static int verify_expr(AVExpr *e)
{
    if (!e) return 0;
    switch (e->type) {
        case e_value:
        case e_const: return 1;
        case e_func0:
        case e_func1:
        case e_squish:
        case e_ld:
        case e_gauss:
        case e_isnan:
        case e_isinf:
        case e_floor:
        case e_ceil:
        case e_trunc:
        case e_sqrt:
        case e_not:
            return verify_expr(e->param[0]);
        default: return verify_expr(e->param[0]) && verify_expr(e->param[1]);
    }
}

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)
{
    Parser p = { 0 };
    AVExpr *e = NULL;
    char *w = av_malloc(strlen(s) + 1);
    char *wp = w;
    const char *s0 = s;
    int ret = 0;

    if (!w)
        return AVERROR(ENOMEM);

    while (*s)
        if (!av_isspace(*s++)) *wp++ = s[-1];
    *wp++ = 0;

    p.class      = &class;
    p.stack_index=100;
    p.s= w;
    p.const_names = const_names;
    p.funcs1      = funcs1;
    p.func1_names = func1_names;
    p.funcs2      = funcs2;
    p.func2_names = func2_names;
    p.log_offset = log_offset;
    p.log_ctx    = log_ctx;

    if ((ret = parse_expr(&e, &p)) < 0)
        goto end;
    if (*p.s) {
        av_expr_free(e);
        av_log(&p, AV_LOG_ERROR, "Invalid chars '%s' at the end of expression '%s'\n", p.s, s0);
        ret = AVERROR(EINVAL);
        goto end;
    }
    if (!verify_expr(e)) {
        av_expr_free(e);
        ret = AVERROR(EINVAL);
        goto end;
    }
    *expr = e;
end:
    av_free(w);
    return ret;
}

double av_expr_eval(AVExpr *e, const double *const_values, void *opaque)
{
    Parser p = { 0 };

    p.const_values = const_values;
    p.opaque     = opaque;
    return eval_expr(&p, e);
}

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)
{
    AVExpr *e = NULL;
    int ret = av_expr_parse(&e, s, const_names, func1_names, funcs1, func2_names, funcs2, log_offset, log_ctx);

    if (ret < 0) {
        *d = NAN;
        return ret;
    }
    *d = av_expr_eval(e, const_values, opaque);
    av_expr_free(e);
    return isnan(*d) ? AVERROR(EINVAL) : 0;
}

#ifdef TEST
#include <string.h>

static const double const_values[] = {
    M_PI,
    M_E,
    0
};

static const char *const const_names[] = {
    "PI",
    "E",
    0
};

int main(int argc, char **argv)
{
    int i;
    double d;
    const char *const *expr;
    static const char *const exprs[] = {
        "",
        "1;2",
        "-20",
        "-PI",
        "+PI",
        "1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)",
        "80G/80Gi",
        "1k",
        "1Gi",
        "1gi",
        "1GiFoo",
        "1k+1k",
        "1Gi*3foo",
        "foo",
        "foo(",
        "foo()",
        "foo)",
        "sin",
        "sin(",
        "sin()",
        "sin)",
        "sin 10",
        "sin(1,2,3)",
        "sin(1 )",
        "1",
        "1foo",
        "bar + PI + E + 100f*2 + foo",
        "13k + 12f - foo(1, 2)",
        "1gi",
        "1Gi",
        "st(0, 123)",
        "st(1, 123); ld(1)",
        "lte(0, 1)",
        "lte(1, 1)",
        "lte(1, 0)",
        "lt(0, 1)",
        "lt(1, 1)",
        "gt(1, 0)",
        "gt(2, 7)",
        "gte(122, 122)",
        /* compute 1+2+...+N */
        "st(0, 1); while(lte(ld(0), 100), st(1, ld(1)+ld(0));st(0, ld(0)+1)); ld(1)",
        /* compute Fib(N) */
        "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)",
        "while(0, 10)",
        "st(0, 1); while(lte(ld(0),100), st(1, ld(1)+ld(0)); st(0, ld(0)+1))",
        "isnan(1)",
        "isnan(NAN)",
        "isnan(INF)",
        "isinf(1)",
        "isinf(NAN)",
        "isinf(INF)",
        "floor(NAN)",
        "floor(123.123)",
        "floor(-123.123)",
        "trunc(123.123)",
        "trunc(-123.123)",
        "ceil(123.123)",
        "ceil(-123.123)",
        "sqrt(1764)",
        "isnan(sqrt(-1))",
        "not(1)",
        "not(NAN)",
        "not(0)",
        "6.0206dB",
        "-3.0103dB",
        NULL
    };

    for (expr = exprs; *expr; expr++) {
        printf("Evaluating '%s'\n", *expr);
        av_expr_parse_and_eval(&d, *expr,
                               const_names, const_values,
                               NULL, NULL, NULL, NULL, NULL, 0, NULL);
        if (isnan(d))
            printf("'%s' -> nan\n\n", *expr);
        else
            printf("'%s' -> %f\n\n", *expr, d);
    }

    av_expr_parse_and_eval(&d, "1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)",
                           const_names, const_values,
                           NULL, NULL, NULL, NULL, NULL, 0, NULL);
    printf("%f == 12.7\n", d);
    av_expr_parse_and_eval(&d, "80G/80Gi",
                           const_names, const_values,
                           NULL, NULL, NULL, NULL, NULL, 0, NULL);
    printf("%f == 0.931322575\n", d);

    if (argc > 1 && !strcmp(argv[1], "-t")) {
        for (i = 0; i < 1050; i++) {
            START_TIMER;
            av_expr_parse_and_eval(&d, "1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)",
                                   const_names, const_values,
                                   NULL, NULL, NULL, NULL, NULL, 0, NULL);
            STOP_TIMER("av_expr_parse_and_eval");
        }
    }

    return 0;
}
#endif