FFmpeg: libavutil/eval.c Source File

00001 /*
00002  * Copyright (c) 2002-2006 Michael Niedermayer <michaelni@gmx.at>
00003  * Copyright (c) 2006 Oded Shimon <ods15@ods15.dyndns.org>
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00029 #include "avutil.h"
00030 #include "eval.h"
00031 
00032 typedef struct Parser {
00033     const AVClass *class;
00034     int stack_index;
00035     char *s;
00036     const double *const_values;
00037     const char * const *const_names;          // NULL terminated
00038     double (* const *funcs1)(void *, double a);           // NULL terminated
00039     const char * const *func1_names;          // NULL terminated
00040     double (* const *funcs2)(void *, double a, double b); // NULL terminated
00041     const char * const *func2_names;          // NULL terminated
00042     void *opaque;
00043     int log_offset;
00044     void *log_ctx;
00045 #define VARS 10
00046     double var[VARS];
00047 } Parser;
00048 
00049 static const AVClass class = { "Eval", av_default_item_name, NULL, LIBAVUTIL_VERSION_INT, offsetof(Parser,log_offset), offsetof(Parser,log_ctx) };
00050 
00051 static const int8_t si_prefixes['z' - 'E' + 1] = {
00052     ['y'-'E']= -24,
00053     ['z'-'E']= -21,
00054     ['a'-'E']= -18,
00055     ['f'-'E']= -15,
00056     ['p'-'E']= -12,
00057     ['n'-'E']= - 9,
00058     ['u'-'E']= - 6,
00059     ['m'-'E']= - 3,
00060     ['c'-'E']= - 2,
00061     ['d'-'E']= - 1,
00062     ['h'-'E']=   2,
00063     ['k'-'E']=   3,
00064     ['K'-'E']=   3,
00065     ['M'-'E']=   6,
00066     ['G'-'E']=   9,
00067     ['T'-'E']=  12,
00068     ['P'-'E']=  15,
00069     ['E'-'E']=  18,
00070     ['Z'-'E']=  21,
00071     ['Y'-'E']=  24,
00072 };
00073 
00074 double av_strtod(const char *numstr, char **tail)
00075 {
00076     double d;
00077     char *next;
00078     if(numstr[0]=='0' && (numstr[1]|0x20)=='x') {
00079         d = strtoul(numstr, &next, 16);
00080     } else
00081         d = strtod(numstr, &next);
00082     /* if parsing succeeded, check for and interpret postfixes */
00083     if (next!=numstr) {
00084         if (*next >= 'E' && *next <= 'z') {
00085             int e= si_prefixes[*next - 'E'];
00086             if (e) {
00087                 if (next[1] == 'i') {
00088                     d*= pow( 2, e/0.3);
00089                     next+=2;
00090                 } else {
00091                     d*= pow(10, e);
00092                     next++;
00093                 }
00094             }
00095         }
00096 
00097         if (*next=='B') {
00098             d*=8;
00099             next++;
00100         }
00101     }
00102     /* if requested, fill in tail with the position after the last parsed
00103        character */
00104     if (tail)
00105         *tail = next;
00106     return d;
00107 }
00108 
00109 #define IS_IDENTIFIER_CHAR(c) ((c) - '0' <= 9U || (c) - 'a' <= 25U || (c) - 'A' <= 25U || (c) == '_')
00110 
00111 static int strmatch(const char *s, const char *prefix)
00112 {
00113     int i;
00114     for (i=0; prefix[i]; i++) {
00115         if (prefix[i] != s[i]) return 0;
00116     }
00117     /* return 1 only if the s identifier is terminated */
00118     return !IS_IDENTIFIER_CHAR(s[i]);
00119 }
00120 
00121 struct AVExpr {
00122     enum {
00123         e_value, e_const, e_func0, e_func1, e_func2,
00124         e_squish, e_gauss, e_ld, e_isnan,
00125         e_mod, e_max, e_min, e_eq, e_gt, e_gte,
00126         e_pow, e_mul, e_div, e_add,
00127         e_last, e_st, e_while, e_floor, e_ceil, e_trunc,
00128         e_sqrt, e_not,
00129     } type;
00130     double value; // is sign in other types
00131     union {
00132         int const_index;
00133         double (*func0)(double);
00134         double (*func1)(void *, double);
00135         double (*func2)(void *, double, double);
00136     } a;
00137     struct AVExpr *param[2];
00138 };
00139 
00140 static double eval_expr(Parser *p, AVExpr *e)
00141 {
00142     switch (e->type) {
00143         case e_value:  return e->value;
00144         case e_const:  return e->value * p->const_values[e->a.const_index];
00145         case e_func0:  return e->value * e->a.func0(eval_expr(p, e->param[0]));
00146         case e_func1:  return e->value * e->a.func1(p->opaque, eval_expr(p, e->param[0]));
00147         case e_func2:  return e->value * e->a.func2(p->opaque, eval_expr(p, e->param[0]), eval_expr(p, e->param[1]));
00148         case e_squish: return 1/(1+exp(4*eval_expr(p, e->param[0])));
00149         case e_gauss: { double d = eval_expr(p, e->param[0]); return exp(-d*d/2)/sqrt(2*M_PI); }
00150         case e_ld:     return e->value * p->var[av_clip(eval_expr(p, e->param[0]), 0, VARS-1)];
00151         case e_isnan:  return e->value * !!isnan(eval_expr(p, e->param[0]));
00152         case e_floor:  return e->value * floor(eval_expr(p, e->param[0]));
00153         case e_ceil :  return e->value * ceil (eval_expr(p, e->param[0]));
00154         case e_trunc:  return e->value * trunc(eval_expr(p, e->param[0]));
00155         case e_sqrt:   return e->value * sqrt (eval_expr(p, e->param[0]));
00156         case e_not:    return e->value * eval_expr(p, e->param[0]) == 0;
00157         case e_while: {
00158             double d = NAN;
00159             while (eval_expr(p, e->param[0]))
00160                 d=eval_expr(p, e->param[1]);
00161             return d;
00162         }
00163         default: {
00164             double d = eval_expr(p, e->param[0]);
00165             double d2 = eval_expr(p, e->param[1]);
00166             switch (e->type) {
00167                 case e_mod: return e->value * (d - floor(d/d2)*d2);
00168                 case e_max: return e->value * (d >  d2 ?   d : d2);
00169                 case e_min: return e->value * (d <  d2 ?   d : d2);
00170                 case e_eq:  return e->value * (d == d2 ? 1.0 : 0.0);
00171                 case e_gt:  return e->value * (d >  d2 ? 1.0 : 0.0);
00172                 case e_gte: return e->value * (d >= d2 ? 1.0 : 0.0);
00173                 case e_pow: return e->value * pow(d, d2);
00174                 case e_mul: return e->value * (d * d2);
00175                 case e_div: return e->value * (d / d2);
00176                 case e_add: return e->value * (d + d2);
00177                 case e_last:return e->value * d2;
00178                 case e_st : return e->value * (p->var[av_clip(d, 0, VARS-1)]= d2);
00179             }
00180         }
00181     }
00182     return NAN;
00183 }
00184 
00185 static int parse_expr(AVExpr **e, Parser *p);
00186 
00187 void av_expr_free(AVExpr *e)
00188 {
00189     if (!e) return;
00190     av_expr_free(e->param[0]);
00191     av_expr_free(e->param[1]);
00192     av_freep(&e);
00193 }
00194 
00195 static int parse_primary(AVExpr **e, Parser *p)
00196 {
00197     AVExpr *d = av_mallocz(sizeof(AVExpr));
00198     char *next = p->s, *s0 = p->s;
00199     int ret, i;
00200 
00201     if (!d)
00202         return AVERROR(ENOMEM);
00203 
00204     /* number */
00205     d->value = av_strtod(p->s, &next);
00206     if (next != p->s) {
00207         d->type = e_value;
00208         p->s= next;
00209         *e = d;
00210         return 0;
00211     }
00212     d->value = 1;
00213 
00214     /* named constants */
00215     for (i=0; p->const_names && p->const_names[i]; i++) {
00216         if (strmatch(p->s, p->const_names[i])) {
00217             p->s+= strlen(p->const_names[i]);
00218             d->type = e_const;
00219             d->a.const_index = i;
00220             *e = d;
00221             return 0;
00222         }
00223     }
00224 
00225     p->s= strchr(p->s, '(');
00226     if (p->s==NULL) {
00227         av_log(p, AV_LOG_ERROR, "Undefined constant or missing '(' in '%s'\n", s0);
00228         p->s= next;
00229         av_expr_free(d);
00230         return AVERROR(EINVAL);
00231     }
00232     p->s++; // "("
00233     if (*next == '(') { // special case do-nothing
00234         av_freep(&d);
00235         if ((ret = parse_expr(&d, p)) < 0)
00236             return ret;
00237         if (p->s[0] != ')') {
00238             av_log(p, AV_LOG_ERROR, "Missing ')' in '%s'\n", s0);
00239             av_expr_free(d);
00240             return AVERROR(EINVAL);
00241         }
00242         p->s++; // ")"
00243         *e = d;
00244         return 0;
00245     }
00246     if ((ret = parse_expr(&(d->param[0]), p)) < 0) {
00247         av_expr_free(d);
00248         return ret;
00249     }
00250     if (p->s[0]== ',') {
00251         p->s++; // ","
00252         parse_expr(&d->param[1], p);
00253     }
00254     if (p->s[0] != ')') {
00255         av_log(p, AV_LOG_ERROR, "Missing ')' or too many args in '%s'\n", s0);
00256         av_expr_free(d);
00257         return AVERROR(EINVAL);
00258     }
00259     p->s++; // ")"
00260 
00261     d->type = e_func0;
00262          if (strmatch(next, "sinh"  )) d->a.func0 = sinh;
00263     else if (strmatch(next, "cosh"  )) d->a.func0 = cosh;
00264     else if (strmatch(next, "tanh"  )) d->a.func0 = tanh;
00265     else if (strmatch(next, "sin"   )) d->a.func0 = sin;
00266     else if (strmatch(next, "cos"   )) d->a.func0 = cos;
00267     else if (strmatch(next, "tan"   )) d->a.func0 = tan;
00268     else if (strmatch(next, "atan"  )) d->a.func0 = atan;
00269     else if (strmatch(next, "asin"  )) d->a.func0 = asin;
00270     else if (strmatch(next, "acos"  )) d->a.func0 = acos;
00271     else if (strmatch(next, "exp"   )) d->a.func0 = exp;
00272     else if (strmatch(next, "log"   )) d->a.func0 = log;
00273     else if (strmatch(next, "abs"   )) d->a.func0 = fabs;
00274     else if (strmatch(next, "squish")) d->type = e_squish;
00275     else if (strmatch(next, "gauss" )) d->type = e_gauss;
00276     else if (strmatch(next, "mod"   )) d->type = e_mod;
00277     else if (strmatch(next, "max"   )) d->type = e_max;
00278     else if (strmatch(next, "min"   )) d->type = e_min;
00279     else if (strmatch(next, "eq"    )) d->type = e_eq;
00280     else if (strmatch(next, "gte"   )) d->type = e_gte;
00281     else if (strmatch(next, "gt"    )) d->type = e_gt;
00282     else if (strmatch(next, "lte"   )) { AVExpr *tmp = d->param[1]; d->param[1] = d->param[0]; d->param[0] = tmp; d->type = e_gt; }
00283     else if (strmatch(next, "lt"    )) { AVExpr *tmp = d->param[1]; d->param[1] = d->param[0]; d->param[0] = tmp; d->type = e_gte; }
00284     else if (strmatch(next, "ld"    )) d->type = e_ld;
00285     else if (strmatch(next, "isnan" )) d->type = e_isnan;
00286     else if (strmatch(next, "st"    )) d->type = e_st;
00287     else if (strmatch(next, "while" )) d->type = e_while;
00288     else if (strmatch(next, "floor" )) d->type = e_floor;
00289     else if (strmatch(next, "ceil"  )) d->type = e_ceil;
00290     else if (strmatch(next, "trunc" )) d->type = e_trunc;
00291     else if (strmatch(next, "sqrt"  )) d->type = e_sqrt;
00292     else if (strmatch(next, "not"   )) d->type = e_not;
00293     else if (strmatch(next, "pow"   )) d->type = e_pow;
00294     else {
00295         for (i=0; p->func1_names && p->func1_names[i]; i++) {
00296             if (strmatch(next, p->func1_names[i])) {
00297                 d->a.func1 = p->funcs1[i];
00298                 d->type = e_func1;
00299                 *e = d;
00300                 return 0;
00301             }
00302         }
00303 
00304         for (i=0; p->func2_names && p->func2_names[i]; i++) {
00305             if (strmatch(next, p->func2_names[i])) {
00306                 d->a.func2 = p->funcs2[i];
00307                 d->type = e_func2;
00308                 *e = d;
00309                 return 0;
00310             }
00311         }
00312 
00313         av_log(p, AV_LOG_ERROR, "Unknown function in '%s'\n", s0);
00314         av_expr_free(d);
00315         return AVERROR(EINVAL);
00316     }
00317 
00318     *e = d;
00319     return 0;
00320 }
00321 
00322 static AVExpr *new_eval_expr(int type, int value, AVExpr *p0, AVExpr *p1)
00323 {
00324     AVExpr *e = av_mallocz(sizeof(AVExpr));
00325     if (!e)
00326         return NULL;
00327     e->type     =type   ;
00328     e->value    =value  ;
00329     e->param[0] =p0     ;
00330     e->param[1] =p1     ;
00331     return e;
00332 }
00333 
00334 static int parse_pow(AVExpr **e, Parser *p, int *sign)
00335 {
00336     *sign= (*p->s == '+') - (*p->s == '-');
00337     p->s += *sign&1;
00338     return parse_primary(e, p);
00339 }
00340 
00341 static int parse_factor(AVExpr **e, Parser *p)
00342 {
00343     int sign, sign2, ret;
00344     AVExpr *e0, *e1, *e2;
00345     if ((ret = parse_pow(&e0, p, &sign)) < 0)
00346         return ret;
00347     while(p->s[0]=='^'){
00348         e1 = e0;
00349         p->s++;
00350         if ((ret = parse_pow(&e2, p, &sign2)) < 0) {
00351             av_expr_free(e1);
00352             return ret;
00353         }
00354         e0 = new_eval_expr(e_pow, 1, e1, e2);
00355         if (!e0) {
00356             av_expr_free(e1);
00357             av_expr_free(e2);
00358             return AVERROR(ENOMEM);
00359         }
00360         if (e0->param[1]) e0->param[1]->value *= (sign2|1);
00361     }
00362     if (e0) e0->value *= (sign|1);
00363 
00364     *e = e0;
00365     return 0;
00366 }
00367 
00368 static int parse_term(AVExpr **e, Parser *p)
00369 {
00370     int ret;
00371     AVExpr *e0, *e1, *e2;
00372     if ((ret = parse_factor(&e0, p)) < 0)
00373         return ret;
00374     while (p->s[0]=='*' || p->s[0]=='/') {
00375         int c= *p->s++;
00376         e1 = e0;
00377         if ((ret = parse_factor(&e2, p)) < 0) {
00378             av_expr_free(e1);
00379             return ret;
00380         }
00381         e0 = new_eval_expr(c == '*' ? e_mul : e_div, 1, e1, e2);
00382         if (!e0) {
00383             av_expr_free(e1);
00384             av_expr_free(e2);
00385             return AVERROR(ENOMEM);
00386         }
00387     }
00388     *e = e0;
00389     return 0;
00390 }
00391 
00392 static int parse_subexpr(AVExpr **e, Parser *p)
00393 {
00394     int ret;
00395     AVExpr *e0, *e1, *e2;
00396     if ((ret = parse_term(&e0, p)) < 0)
00397         return ret;
00398     while (*p->s == '+' || *p->s == '-') {
00399         e1 = e0;
00400         if ((ret = parse_term(&e2, p)) < 0) {
00401             av_expr_free(e1);
00402             return ret;
00403         }
00404         e0 = new_eval_expr(e_add, 1, e1, e2);
00405         if (!e0) {
00406             av_expr_free(e1);
00407             av_expr_free(e2);
00408             return AVERROR(ENOMEM);
00409         }
00410     };
00411 
00412     *e = e0;
00413     return 0;
00414 }
00415 
00416 static int parse_expr(AVExpr **e, Parser *p)
00417 {
00418     int ret;
00419     AVExpr *e0, *e1, *e2;
00420     if (p->stack_index <= 0) //protect against stack overflows
00421         return AVERROR(EINVAL);
00422     p->stack_index--;
00423 
00424     if ((ret = parse_subexpr(&e0, p)) < 0)
00425         return ret;
00426     while (*p->s == ';') {
00427         p->s++;
00428         e1 = e0;
00429         if ((ret = parse_subexpr(&e2, p)) < 0) {
00430             av_expr_free(e1);
00431             return ret;
00432         }
00433         e0 = new_eval_expr(e_last, 1, e1, e2);
00434         if (!e0) {
00435             av_expr_free(e1);
00436             av_expr_free(e2);
00437             return AVERROR(ENOMEM);
00438         }
00439     };
00440 
00441     p->stack_index++;
00442     *e = e0;
00443     return 0;
00444 }
00445 
00446 static int verify_expr(AVExpr *e)
00447 {
00448     if (!e) return 0;
00449     switch (e->type) {
00450         case e_value:
00451         case e_const: return 1;
00452         case e_func0:
00453         case e_func1:
00454         case e_squish:
00455         case e_ld:
00456         case e_gauss:
00457         case e_isnan:
00458         case e_floor:
00459         case e_ceil:
00460         case e_trunc:
00461         case e_sqrt:
00462         case e_not:
00463             return verify_expr(e->param[0]);
00464         default: return verify_expr(e->param[0]) && verify_expr(e->param[1]);
00465     }
00466 }
00467 
00468 int av_expr_parse(AVExpr **expr, const char *s,
00469                   const char * const *const_names,
00470                   const char * const *func1_names, double (* const *funcs1)(void *, double),
00471                   const char * const *func2_names, double (* const *funcs2)(void *, double, double),
00472                   int log_offset, void *log_ctx)
00473 {
00474     Parser p;
00475     AVExpr *e = NULL;
00476     char *w = av_malloc(strlen(s) + 1);
00477     char *wp = w;
00478     const char *s0 = s;
00479     int ret = 0;
00480 
00481     if (!w)
00482         return AVERROR(ENOMEM);
00483 
00484     while (*s)
00485         if (!isspace(*s++)) *wp++ = s[-1];
00486     *wp++ = 0;
00487 
00488     p.class      = &class;
00489     p.stack_index=100;
00490     p.s= w;
00491     p.const_names = const_names;
00492     p.funcs1      = funcs1;
00493     p.func1_names = func1_names;
00494     p.funcs2      = funcs2;
00495     p.func2_names = func2_names;
00496     p.log_offset = log_offset;
00497     p.log_ctx    = log_ctx;
00498 
00499     if ((ret = parse_expr(&e, &p)) < 0)
00500         goto end;
00501     if (*p.s) {
00502         av_expr_free(e);
00503         av_log(&p, AV_LOG_ERROR, "Invalid chars '%s' at the end of expression '%s'\n", p.s, s0);
00504         ret = AVERROR(EINVAL);
00505         goto end;
00506     }
00507     if (!verify_expr(e)) {
00508         av_expr_free(e);
00509         ret = AVERROR(EINVAL);
00510         goto end;
00511     }
00512     *expr = e;
00513 end:
00514     av_free(w);
00515     return ret;
00516 }
00517 
00518 double av_expr_eval(AVExpr *e, const double *const_values, void *opaque)
00519 {
00520     Parser p;
00521 
00522     p.const_values = const_values;
00523     p.opaque     = opaque;
00524     return eval_expr(&p, e);
00525 }
00526 
00527 int av_expr_parse_and_eval(double *d, const char *s,
00528                            const char * const *const_names, const double *const_values,
00529                            const char * const *func1_names, double (* const *funcs1)(void *, double),
00530                            const char * const *func2_names, double (* const *funcs2)(void *, double, double),
00531                            void *opaque, int log_offset, void *log_ctx)
00532 {
00533     AVExpr *e = NULL;
00534     int ret = av_expr_parse(&e, s, const_names, func1_names, funcs1, func2_names, funcs2, log_offset, log_ctx);
00535 
00536     if (ret < 0) {
00537         *d = NAN;
00538         return ret;
00539     }
00540     *d = av_expr_eval(e, const_values, opaque);
00541     av_expr_free(e);
00542     return isnan(*d) ? AVERROR(EINVAL) : 0;
00543 }
00544 
00545 #if FF_API_OLD_EVAL_NAMES
00546 int av_parse_expr(AVExpr **expr, const char *s,
00547                   const char * const *const_names,
00548                   const char * const *func1_names, double (* const *funcs1)(void *, double),
00549                   const char * const *func2_names, double (* const *funcs2)(void *, double, double),
00550                   int log_offset, void *log_ctx)
00551 {
00552     return av_expr_parse(expr, s, const_names, func1_names, funcs1, func2_names, funcs2,
00553                       log_offset, log_ctx);
00554 }
00555 
00556 double av_eval_expr(AVExpr *e, const double *const_values, void *opaque)
00557 {
00558     return av_expr_eval(e, const_values, opaque);
00559 }
00560 
00561 int av_parse_and_eval_expr(double *res, const char *s,
00562                            const char * const *const_names, const double *const_values,
00563                            const char * const *func1_names, double (* const *funcs1)(void *, double),
00564                            const char * const *func2_names, double (* const *funcs2)(void *, double, double),
00565                            void *opaque, int log_offset, void *log_ctx)
00566 {
00567     return av_expr_parse_and_eval(res, s, const_names, const_values, func1_names, funcs1, func2_names, funcs2,
00568                                   opaque, log_offset, log_ctx);
00569 }
00570 
00571 void av_free_expr(AVExpr *e)
00572 {
00573     av_expr_free(e);
00574 }
00575 #endif /* FF_API_OLD_EVAL_NAMES */
00576 
00577 #ifdef TEST
00578 #undef printf
00579 static double const_values[] = {
00580     M_PI,
00581     M_E,
00582     0
00583 };
00584 
00585 static const char *const_names[] = {
00586     "PI",
00587     "E",
00588     0
00589 };
00590 
00591 int main(void)
00592 {
00593     int i;
00594     double d;
00595     const char **expr, *exprs[] = {
00596         "",
00597         "1;2",
00598         "-20",
00599         "-PI",
00600         "+PI",
00601         "1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)",
00602         "80G/80Gi"
00603         "1k",
00604         "1Gi",
00605         "1gi",
00606         "1GiFoo",
00607         "1k+1k",
00608         "1Gi*3foo",
00609         "foo",
00610         "foo(",
00611         "foo()",
00612         "foo)",
00613         "sin",
00614         "sin(",
00615         "sin()",
00616         "sin)",
00617         "sin 10",
00618         "sin(1,2,3)",
00619         "sin(1 )",
00620         "1",
00621         "1foo",
00622         "bar + PI + E + 100f*2 + foo",
00623         "13k + 12f - foo(1, 2)",
00624         "1gi",
00625         "1Gi",
00626         "st(0, 123)",
00627         "st(1, 123); ld(1)",
00628         /* compute 1+2+...+N */
00629         "st(0, 1); while(lte(ld(0), 100), st(1, ld(1)+ld(0));st(0, ld(0)+1)); ld(1)",
00630         /* compute Fib(N) */
00631         "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)",
00632         "while(0, 10)",
00633         "st(0, 1); while(lte(ld(0),100), st(1, ld(1)+ld(0)); st(0, ld(0)+1))",
00634         "isnan(1)",
00635         "isnan(NAN)",
00636         "floor(NAN)",
00637         "floor(123.123)",
00638         "floor(-123.123)",
00639         "trunc(123.123)",
00640         "trunc(-123.123)",
00641         "ceil(123.123)",
00642         "ceil(-123.123)",
00643         "sqrt(1764)",
00644         "sqrt(-1)",
00645         "not(1)",
00646         "not(NAN)",
00647         "not(0)",
00648         "pow(0,1.23)",
00649         "pow(PI,1.23)",
00650         "PI^1.23",
00651         "pow(-1,1.23)",
00652         NULL
00653     };
00654 
00655     for (expr = exprs; *expr; expr++) {
00656         printf("Evaluating '%s'\n", *expr);
00657         av_expr_parse_and_eval(&d, *expr,
00658                                const_names, const_values,
00659                                NULL, NULL, NULL, NULL, NULL, 0, NULL);
00660         printf("'%s' -> %f\n\n", *expr, d);
00661     }
00662 
00663     av_expr_parse_and_eval(&d, "1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)",
00664                            const_names, const_values,
00665                            NULL, NULL, NULL, NULL, NULL, 0, NULL);
00666     printf("%f == 12.7\n", d);
00667     av_expr_parse_and_eval(&d, "80G/80Gi",
00668                            const_names, const_values,
00669                            NULL, NULL, NULL, NULL, NULL, 0, NULL);
00670     printf("%f == 0.931322575\n", d);
00671 
00672     for (i=0; i<1050; i++) {
00673         START_TIMER
00674             av_expr_parse_and_eval(&d, "1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)",
00675                                    const_names, const_values,
00676                                    NULL, NULL, NULL, NULL, NULL, 0, NULL);
00677         STOP_TIMER("av_expr_parse_and_eval")
00678     }
00679     return 0;
00680 }
00681 #endif