yading@11: /*
yading@11:  * Copyright (c) 2002-2006 Michael Niedermayer <michaelni@gmx.at>
yading@11:  * Copyright (c) 2006 Oded Shimon <ods15@ods15.dyndns.org>
yading@11:  *
yading@11:  * This file is part of FFmpeg.
yading@11:  *
yading@11:  * FFmpeg is free software; you can redistribute it and/or
yading@11:  * modify it under the terms of the GNU Lesser General Public
yading@11:  * License as published by the Free Software Foundation; either
yading@11:  * version 2.1 of the License, or (at your option) any later version.
yading@11:  *
yading@11:  * FFmpeg is distributed in the hope that it will be useful,
yading@11:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@11:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@11:  * Lesser General Public License for more details.
yading@11:  *
yading@11:  * You should have received a copy of the GNU Lesser General Public
yading@11:  * License along with FFmpeg; if not, write to the Free Software
yading@11:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@11:  */
yading@11: 
yading@11: /**
yading@11:  * @file
yading@11:  * simple arithmetic expression evaluator.
yading@11:  *
yading@11:  * see http://joe.hotchkiss.com/programming/eval/eval.html
yading@11:  */
yading@11: 
yading@11: #include <float.h>
yading@11: #include "avutil.h"
yading@11: #include "common.h"
yading@11: #include "eval.h"
yading@11: #include "log.h"
yading@11: #include "mathematics.h"
yading@11: #include "time.h"
yading@11: #include "avstring.h"
yading@11: 
yading@11: typedef struct Parser {
yading@11:     const AVClass *class;
yading@11:     int stack_index;
yading@11:     char *s;
yading@11:     const double *const_values;
yading@11:     const char * const *const_names;          // NULL terminated
yading@11:     double (* const *funcs1)(void *, double a);           // NULL terminated
yading@11:     const char * const *func1_names;          // NULL terminated
yading@11:     double (* const *funcs2)(void *, double a, double b); // NULL terminated
yading@11:     const char * const *func2_names;          // NULL terminated
yading@11:     void *opaque;
yading@11:     int log_offset;
yading@11:     void *log_ctx;
yading@11: #define VARS 10
yading@11:     double *var;
yading@11: } Parser;
yading@11: 
yading@11: static const AVClass class = { "Eval", av_default_item_name, NULL, LIBAVUTIL_VERSION_INT, offsetof(Parser,log_offset), offsetof(Parser,log_ctx) };
yading@11: 
yading@11: static const int8_t si_prefixes['z' - 'E' + 1] = {
yading@11:     ['y'-'E']= -24,
yading@11:     ['z'-'E']= -21,
yading@11:     ['a'-'E']= -18,
yading@11:     ['f'-'E']= -15,
yading@11:     ['p'-'E']= -12,
yading@11:     ['n'-'E']= - 9,
yading@11:     ['u'-'E']= - 6,
yading@11:     ['m'-'E']= - 3,
yading@11:     ['c'-'E']= - 2,
yading@11:     ['d'-'E']= - 1,
yading@11:     ['h'-'E']=   2,
yading@11:     ['k'-'E']=   3,
yading@11:     ['K'-'E']=   3,
yading@11:     ['M'-'E']=   6,
yading@11:     ['G'-'E']=   9,
yading@11:     ['T'-'E']=  12,
yading@11:     ['P'-'E']=  15,
yading@11:     ['E'-'E']=  18,
yading@11:     ['Z'-'E']=  21,
yading@11:     ['Y'-'E']=  24,
yading@11: };
yading@11: 
yading@11: static const struct {
yading@11:     const char *name;
yading@11:     double value;
yading@11: } constants[] = {
yading@11:     { "E",   M_E   },
yading@11:     { "PI",  M_PI  },
yading@11:     { "PHI", M_PHI },
yading@11: };
yading@11: 
yading@11: double av_strtod(const char *numstr, char **tail)
yading@11: {
yading@11:     double d;
yading@11:     char *next;
yading@11:     if(numstr[0]=='0' && (numstr[1]|0x20)=='x') {
yading@11:         d = strtoul(numstr, &next, 16);
yading@11:     } else
yading@11:         d = strtod(numstr, &next);
yading@11:     /* if parsing succeeded, check for and interpret postfixes */
yading@11:     if (next!=numstr) {
yading@11:         if (next[0] == 'd' && next[1] == 'B') {
yading@11:             /* treat dB as decibels instead of decibytes */
yading@11:             d = pow(10, d / 20);
yading@11:             next += 2;
yading@11:         } else if (*next >= 'E' && *next <= 'z') {
yading@11:             int e= si_prefixes[*next - 'E'];
yading@11:             if (e) {
yading@11:                 if (next[1] == 'i') {
yading@11:                     d*= pow( 2, e/0.3);
yading@11:                     next+=2;
yading@11:                 } else {
yading@11:                     d*= pow(10, e);
yading@11:                     next++;
yading@11:                 }
yading@11:             }
yading@11:         }
yading@11: 
yading@11:         if (*next=='B') {
yading@11:             d*=8;
yading@11:             next++;
yading@11:         }
yading@11:     }
yading@11:     /* if requested, fill in tail with the position after the last parsed
yading@11:        character */
yading@11:     if (tail)
yading@11:         *tail = next;
yading@11:     return d;
yading@11: }
yading@11: 
yading@11: #define IS_IDENTIFIER_CHAR(c) ((c) - '0' <= 9U || (c) - 'a' <= 25U || (c) - 'A' <= 25U || (c) == '_')
yading@11: 
yading@11: static int strmatch(const char *s, const char *prefix)
yading@11: {
yading@11:     int i;
yading@11:     for (i=0; prefix[i]; i++) {
yading@11:         if (prefix[i] != s[i]) return 0;
yading@11:     }
yading@11:     /* return 1 only if the s identifier is terminated */
yading@11:     return !IS_IDENTIFIER_CHAR(s[i]);
yading@11: }
yading@11: 
yading@11: struct AVExpr {
yading@11:     enum {
yading@11:         e_value, e_const, e_func0, e_func1, e_func2,
yading@11:         e_squish, e_gauss, e_ld, e_isnan, e_isinf,
yading@11:         e_mod, e_max, e_min, e_eq, e_gt, e_gte, e_lte, e_lt,
yading@11:         e_pow, e_mul, e_div, e_add,
yading@11:         e_last, e_st, e_while, e_taylor, e_root, e_floor, e_ceil, e_trunc,
yading@11:         e_sqrt, e_not, e_random, e_hypot, e_gcd,
yading@11:         e_if, e_ifnot, e_print, e_bitand, e_bitor, e_between,
yading@11:     } type;
yading@11:     double value; // is sign in other types
yading@11:     union {
yading@11:         int const_index;
yading@11:         double (*func0)(double);
yading@11:         double (*func1)(void *, double);
yading@11:         double (*func2)(void *, double, double);
yading@11:     } a;
yading@11:     struct AVExpr *param[3];
yading@11:     double *var;
yading@11: };
yading@11: 
yading@11: static double etime(double v)
yading@11: {
yading@11:     return av_gettime() * 0.000001;
yading@11: }
yading@11: 
yading@11: static double eval_expr(Parser *p, AVExpr *e)
yading@11: {
yading@11:     switch (e->type) {
yading@11:         case e_value:  return e->value;
yading@11:         case e_const:  return e->value * p->const_values[e->a.const_index];
yading@11:         case e_func0:  return e->value * e->a.func0(eval_expr(p, e->param[0]));
yading@11:         case e_func1:  return e->value * e->a.func1(p->opaque, eval_expr(p, e->param[0]));
yading@11:         case e_func2:  return e->value * e->a.func2(p->opaque, eval_expr(p, e->param[0]), eval_expr(p, e->param[1]));
yading@11:         case e_squish: return 1/(1+exp(4*eval_expr(p, e->param[0])));
yading@11:         case e_gauss: { double d = eval_expr(p, e->param[0]); return exp(-d*d/2)/sqrt(2*M_PI); }
yading@11:         case e_ld:     return e->value * p->var[av_clip(eval_expr(p, e->param[0]), 0, VARS-1)];
yading@11:         case e_isnan:  return e->value * !!isnan(eval_expr(p, e->param[0]));
yading@11:         case e_isinf:  return e->value * !!isinf(eval_expr(p, e->param[0]));
yading@11:         case e_floor:  return e->value * floor(eval_expr(p, e->param[0]));
yading@11:         case e_ceil :  return e->value * ceil (eval_expr(p, e->param[0]));
yading@11:         case e_trunc:  return e->value * trunc(eval_expr(p, e->param[0]));
yading@11:         case e_sqrt:   return e->value * sqrt (eval_expr(p, e->param[0]));
yading@11:         case e_not:    return e->value * (eval_expr(p, e->param[0]) == 0);
yading@11:         case e_if:     return e->value * (eval_expr(p, e->param[0]) ? eval_expr(p, e->param[1]) :
yading@11:                                           e->param[2] ? eval_expr(p, e->param[2]) : 0);
yading@11:         case e_ifnot:  return e->value * (!eval_expr(p, e->param[0]) ? eval_expr(p, e->param[1]) :
yading@11:                                           e->param[2] ? eval_expr(p, e->param[2]) : 0);
yading@11:         case e_between: {
yading@11:             double d = eval_expr(p, e->param[0]);
yading@11:             return e->value * (d >= eval_expr(p, e->param[1]) &&
yading@11:                                d <= eval_expr(p, e->param[2]));
yading@11:         }
yading@11:         case e_print: {
yading@11:             double x = eval_expr(p, e->param[0]);
yading@11:             int level = e->param[1] ? av_clip(eval_expr(p, e->param[1]), INT_MIN, INT_MAX) : AV_LOG_INFO;
yading@11:             av_log(p, level, "%f\n", x);
yading@11:             return x;
yading@11:         }
yading@11:         case e_random:{
yading@11:             int idx= av_clip(eval_expr(p, e->param[0]), 0, VARS-1);
yading@11:             uint64_t r= isnan(p->var[idx]) ? 0 : p->var[idx];
yading@11:             r= r*1664525+1013904223;
yading@11:             p->var[idx]= r;
yading@11:             return e->value * (r * (1.0/UINT64_MAX));
yading@11:         }
yading@11:         case e_while: {
yading@11:             double d = NAN;
yading@11:             while (eval_expr(p, e->param[0]))
yading@11:                 d=eval_expr(p, e->param[1]);
yading@11:             return d;
yading@11:         }
yading@11:         case e_taylor: {
yading@11:             double t = 1, d = 0, v;
yading@11:             double x = eval_expr(p, e->param[1]);
yading@11:             int id = e->param[2] ? av_clip(eval_expr(p, e->param[2]), 0, VARS-1) : 0;
yading@11:             int i;
yading@11:             double var0 = p->var[id];
yading@11:             for(i=0; i<1000; i++) {
yading@11:                 double ld = d;
yading@11:                 p->var[id] = i;
yading@11:                 v = eval_expr(p, e->param[0]);
yading@11:                 d += t*v;
yading@11:                 if(ld==d && v)
yading@11:                     break;
yading@11:                 t *= x / (i+1);
yading@11:             }
yading@11:             p->var[id] = var0;
yading@11:             return d;
yading@11:         }
yading@11:         case e_root: {
yading@11:             int i, j;
yading@11:             double low = -1, high = -1, v, low_v = -DBL_MAX, high_v = DBL_MAX;
yading@11:             double var0 = p->var[0];
yading@11:             double x_max = eval_expr(p, e->param[1]);
yading@11:             for(i=-1; i<1024; i++) {
yading@11:                 if(i<255) {
yading@11:                     p->var[0] = av_reverse[i&255]*x_max/255;
yading@11:                 } else {
yading@11:                     p->var[0] = x_max*pow(0.9, i-255);
yading@11:                     if (i&1) p->var[0] *= -1;
yading@11:                     if (i&2) p->var[0] += low;
yading@11:                     else     p->var[0] += high;
yading@11:                 }
yading@11:                 v = eval_expr(p, e->param[0]);
yading@11:                 if (v<=0 && v>low_v) {
yading@11:                     low    = p->var[0];
yading@11:                     low_v  = v;
yading@11:                 }
yading@11:                 if (v>=0 && v<high_v) {
yading@11:                     high   = p->var[0];
yading@11:                     high_v = v;
yading@11:                 }
yading@11:                 if (low>=0 && high>=0){
yading@11:                     for (j=0; j<1000; j++) {
yading@11:                         p->var[0] = (low+high)*0.5;
yading@11:                         if (low == p->var[0] || high == p->var[0])
yading@11:                             break;
yading@11:                         v = eval_expr(p, e->param[0]);
yading@11:                         if (v<=0) low = p->var[0];
yading@11:                         if (v>=0) high= p->var[0];
yading@11:                         if (isnan(v)) {
yading@11:                             low = high = v;
yading@11:                             break;
yading@11:                         }
yading@11:                     }
yading@11:                     break;
yading@11:                 }
yading@11:             }
yading@11:             p->var[0] = var0;
yading@11:             return -low_v<high_v ? low : high;
yading@11:         }
yading@11:         default: {
yading@11:             double d = eval_expr(p, e->param[0]);
yading@11:             double d2 = eval_expr(p, e->param[1]);
yading@11:             switch (e->type) {
yading@11:                 case e_mod: return e->value * (d - floor((!CONFIG_FTRAPV || d2) ? d / d2 : d * INFINITY) * d2);
yading@11:                 case e_gcd: return e->value * av_gcd(d,d2);
yading@11:                 case e_max: return e->value * (d >  d2 ?   d : d2);
yading@11:                 case e_min: return e->value * (d <  d2 ?   d : d2);
yading@11:                 case e_eq:  return e->value * (d == d2 ? 1.0 : 0.0);
yading@11:                 case e_gt:  return e->value * (d >  d2 ? 1.0 : 0.0);
yading@11:                 case e_gte: return e->value * (d >= d2 ? 1.0 : 0.0);
yading@11:                 case e_lt:  return e->value * (d <  d2 ? 1.0 : 0.0);
yading@11:                 case e_lte: return e->value * (d <= d2 ? 1.0 : 0.0);
yading@11:                 case e_pow: return e->value * pow(d, d2);
yading@11:                 case e_mul: return e->value * (d * d2);
yading@11:                 case e_div: return e->value * ((!CONFIG_FTRAPV || d2 ) ? (d / d2) : d * INFINITY);
yading@11:                 case e_add: return e->value * (d + d2);
yading@11:                 case e_last:return e->value * d2;
yading@11:                 case e_st : return e->value * (p->var[av_clip(d, 0, VARS-1)]= d2);
yading@11:                 case e_hypot:return e->value * (sqrt(d*d + d2*d2));
yading@11:                 case e_bitand: return isnan(d) || isnan(d2) ? NAN : e->value * ((long int)d & (long int)d2);
yading@11:                 case e_bitor:  return isnan(d) || isnan(d2) ? NAN : e->value * ((long int)d | (long int)d2);
yading@11:             }
yading@11:         }
yading@11:     }
yading@11:     return NAN;
yading@11: }
yading@11: 
yading@11: static int parse_expr(AVExpr **e, Parser *p);
yading@11: 
yading@11: void av_expr_free(AVExpr *e)
yading@11: {
yading@11:     if (!e) return;
yading@11:     av_expr_free(e->param[0]);
yading@11:     av_expr_free(e->param[1]);
yading@11:     av_expr_free(e->param[2]);
yading@11:     av_freep(&e->var);
yading@11:     av_freep(&e);
yading@11: }
yading@11: 
yading@11: static int parse_primary(AVExpr **e, Parser *p)
yading@11: {
yading@11:     AVExpr *d = av_mallocz(sizeof(AVExpr));
yading@11:     char *next = p->s, *s0 = p->s;
yading@11:     int ret, i;
yading@11: 
yading@11:     if (!d)
yading@11:         return AVERROR(ENOMEM);
yading@11: 
yading@11:     /* number */
yading@11:     d->value = av_strtod(p->s, &next);
yading@11:     if (next != p->s) {
yading@11:         d->type = e_value;
yading@11:         p->s= next;
yading@11:         *e = d;
yading@11:         return 0;
yading@11:     }
yading@11:     d->value = 1;
yading@11: 
yading@11:     /* named constants */
yading@11:     for (i=0; p->const_names && p->const_names[i]; i++) {
yading@11:         if (strmatch(p->s, p->const_names[i])) {
yading@11:             p->s+= strlen(p->const_names[i]);
yading@11:             d->type = e_const;
yading@11:             d->a.const_index = i;
yading@11:             *e = d;
yading@11:             return 0;
yading@11:         }
yading@11:     }
yading@11:     for (i = 0; i < FF_ARRAY_ELEMS(constants); i++) {
yading@11:         if (strmatch(p->s, constants[i].name)) {
yading@11:             p->s += strlen(constants[i].name);
yading@11:             d->type = e_value;
yading@11:             d->value = constants[i].value;
yading@11:             *e = d;
yading@11:             return 0;
yading@11:         }
yading@11:     }
yading@11: 
yading@11:     p->s= strchr(p->s, '(');
yading@11:     if (p->s==NULL) {
yading@11:         av_log(p, AV_LOG_ERROR, "Undefined constant or missing '(' in '%s'\n", s0);
yading@11:         p->s= next;
yading@11:         av_expr_free(d);
yading@11:         return AVERROR(EINVAL);
yading@11:     }
yading@11:     p->s++; // "("
yading@11:     if (*next == '(') { // special case do-nothing
yading@11:         av_freep(&d);
yading@11:         if ((ret = parse_expr(&d, p)) < 0)
yading@11:             return ret;
yading@11:         if (p->s[0] != ')') {
yading@11:             av_log(p, AV_LOG_ERROR, "Missing ')' in '%s'\n", s0);
yading@11:             av_expr_free(d);
yading@11:             return AVERROR(EINVAL);
yading@11:         }
yading@11:         p->s++; // ")"
yading@11:         *e = d;
yading@11:         return 0;
yading@11:     }
yading@11:     if ((ret = parse_expr(&(d->param[0]), p)) < 0) {
yading@11:         av_expr_free(d);
yading@11:         return ret;
yading@11:     }
yading@11:     if (p->s[0]== ',') {
yading@11:         p->s++; // ","
yading@11:         parse_expr(&d->param[1], p);
yading@11:     }
yading@11:     if (p->s[0]== ',') {
yading@11:         p->s++; // ","
yading@11:         parse_expr(&d->param[2], p);
yading@11:     }
yading@11:     if (p->s[0] != ')') {
yading@11:         av_log(p, AV_LOG_ERROR, "Missing ')' or too many args in '%s'\n", s0);
yading@11:         av_expr_free(d);
yading@11:         return AVERROR(EINVAL);
yading@11:     }
yading@11:     p->s++; // ")"
yading@11: 
yading@11:     d->type = e_func0;
yading@11:          if (strmatch(next, "sinh"  )) d->a.func0 = sinh;
yading@11:     else if (strmatch(next, "cosh"  )) d->a.func0 = cosh;
yading@11:     else if (strmatch(next, "tanh"  )) d->a.func0 = tanh;
yading@11:     else if (strmatch(next, "sin"   )) d->a.func0 = sin;
yading@11:     else if (strmatch(next, "cos"   )) d->a.func0 = cos;
yading@11:     else if (strmatch(next, "tan"   )) d->a.func0 = tan;
yading@11:     else if (strmatch(next, "atan"  )) d->a.func0 = atan;
yading@11:     else if (strmatch(next, "asin"  )) d->a.func0 = asin;
yading@11:     else if (strmatch(next, "acos"  )) d->a.func0 = acos;
yading@11:     else if (strmatch(next, "exp"   )) d->a.func0 = exp;
yading@11:     else if (strmatch(next, "log"   )) d->a.func0 = log;
yading@11:     else if (strmatch(next, "abs"   )) d->a.func0 = fabs;
yading@11:     else if (strmatch(next, "time"  )) d->a.func0 = etime;
yading@11:     else if (strmatch(next, "squish")) d->type = e_squish;
yading@11:     else if (strmatch(next, "gauss" )) d->type = e_gauss;
yading@11:     else if (strmatch(next, "mod"   )) d->type = e_mod;
yading@11:     else if (strmatch(next, "max"   )) d->type = e_max;
yading@11:     else if (strmatch(next, "min"   )) d->type = e_min;
yading@11:     else if (strmatch(next, "eq"    )) d->type = e_eq;
yading@11:     else if (strmatch(next, "gte"   )) d->type = e_gte;
yading@11:     else if (strmatch(next, "gt"    )) d->type = e_gt;
yading@11:     else if (strmatch(next, "lte"   )) d->type = e_lte;
yading@11:     else if (strmatch(next, "lt"    )) d->type = e_lt;
yading@11:     else if (strmatch(next, "ld"    )) d->type = e_ld;
yading@11:     else if (strmatch(next, "isnan" )) d->type = e_isnan;
yading@11:     else if (strmatch(next, "isinf" )) d->type = e_isinf;
yading@11:     else if (strmatch(next, "st"    )) d->type = e_st;
yading@11:     else if (strmatch(next, "while" )) d->type = e_while;
yading@11:     else if (strmatch(next, "taylor")) d->type = e_taylor;
yading@11:     else if (strmatch(next, "root"  )) d->type = e_root;
yading@11:     else if (strmatch(next, "floor" )) d->type = e_floor;
yading@11:     else if (strmatch(next, "ceil"  )) d->type = e_ceil;
yading@11:     else if (strmatch(next, "trunc" )) d->type = e_trunc;
yading@11:     else if (strmatch(next, "sqrt"  )) d->type = e_sqrt;
yading@11:     else if (strmatch(next, "not"   )) d->type = e_not;
yading@11:     else if (strmatch(next, "pow"   )) d->type = e_pow;
yading@11:     else if (strmatch(next, "print" )) d->type = e_print;
yading@11:     else if (strmatch(next, "random")) d->type = e_random;
yading@11:     else if (strmatch(next, "hypot" )) d->type = e_hypot;
yading@11:     else if (strmatch(next, "gcd"   )) d->type = e_gcd;
yading@11:     else if (strmatch(next, "if"    )) d->type = e_if;
yading@11:     else if (strmatch(next, "ifnot" )) d->type = e_ifnot;
yading@11:     else if (strmatch(next, "bitand")) d->type = e_bitand;
yading@11:     else if (strmatch(next, "bitor" )) d->type = e_bitor;
yading@11:     else if (strmatch(next, "between"))d->type = e_between;
yading@11:     else {
yading@11:         for (i=0; p->func1_names && p->func1_names[i]; i++) {
yading@11:             if (strmatch(next, p->func1_names[i])) {
yading@11:                 d->a.func1 = p->funcs1[i];
yading@11:                 d->type = e_func1;
yading@11:                 *e = d;
yading@11:                 return 0;
yading@11:             }
yading@11:         }
yading@11: 
yading@11:         for (i=0; p->func2_names && p->func2_names[i]; i++) {
yading@11:             if (strmatch(next, p->func2_names[i])) {
yading@11:                 d->a.func2 = p->funcs2[i];
yading@11:                 d->type = e_func2;
yading@11:                 *e = d;
yading@11:                 return 0;
yading@11:             }
yading@11:         }
yading@11: 
yading@11:         av_log(p, AV_LOG_ERROR, "Unknown function in '%s'\n", s0);
yading@11:         av_expr_free(d);
yading@11:         return AVERROR(EINVAL);
yading@11:     }
yading@11: 
yading@11:     *e = d;
yading@11:     return 0;
yading@11: }
yading@11: 
yading@11: static AVExpr *make_eval_expr(int type, int value, AVExpr *p0, AVExpr *p1)
yading@11: {
yading@11:     AVExpr *e = av_mallocz(sizeof(AVExpr));
yading@11:     if (!e)
yading@11:         return NULL;
yading@11:     e->type     =type   ;
yading@11:     e->value    =value  ;
yading@11:     e->param[0] =p0     ;
yading@11:     e->param[1] =p1     ;
yading@11:     return e;
yading@11: }
yading@11: 
yading@11: static int parse_pow(AVExpr **e, Parser *p, int *sign)
yading@11: {
yading@11:     *sign= (*p->s == '+') - (*p->s == '-');
yading@11:     p->s += *sign&1;
yading@11:     return parse_primary(e, p);
yading@11: }
yading@11: 
yading@11: static int parse_dB(AVExpr **e, Parser *p, int *sign)
yading@11: {
yading@11:     /* do not filter out the negative sign when parsing a dB value.
yading@11:        for example, -3dB is not the same as -(3dB) */
yading@11:     if (*p->s == '-') {
yading@11:         char *next;
yading@11:         double av_unused v = strtod(p->s, &next);
yading@11:         if (next != p->s && next[0] == 'd' && next[1] == 'B') {
yading@11:             *sign = 0;
yading@11:             return parse_primary(e, p);
yading@11:         }
yading@11:     }
yading@11:     return parse_pow(e, p, sign);
yading@11: }
yading@11: 
yading@11: static int parse_factor(AVExpr **e, Parser *p)
yading@11: {
yading@11:     int sign, sign2, ret;
yading@11:     AVExpr *e0, *e1, *e2;
yading@11:     if ((ret = parse_dB(&e0, p, &sign)) < 0)
yading@11:         return ret;
yading@11:     while(p->s[0]=='^'){
yading@11:         e1 = e0;
yading@11:         p->s++;
yading@11:         if ((ret = parse_dB(&e2, p, &sign2)) < 0) {
yading@11:             av_expr_free(e1);
yading@11:             return ret;
yading@11:         }
yading@11:         e0 = make_eval_expr(e_pow, 1, e1, e2);
yading@11:         if (!e0) {
yading@11:             av_expr_free(e1);
yading@11:             av_expr_free(e2);
yading@11:             return AVERROR(ENOMEM);
yading@11:         }
yading@11:         if (e0->param[1]) e0->param[1]->value *= (sign2|1);
yading@11:     }
yading@11:     if (e0) e0->value *= (sign|1);
yading@11: 
yading@11:     *e = e0;
yading@11:     return 0;
yading@11: }
yading@11: 
yading@11: static int parse_term(AVExpr **e, Parser *p)
yading@11: {
yading@11:     int ret;
yading@11:     AVExpr *e0, *e1, *e2;
yading@11:     if ((ret = parse_factor(&e0, p)) < 0)
yading@11:         return ret;
yading@11:     while (p->s[0]=='*' || p->s[0]=='/') {
yading@11:         int c= *p->s++;
yading@11:         e1 = e0;
yading@11:         if ((ret = parse_factor(&e2, p)) < 0) {
yading@11:             av_expr_free(e1);
yading@11:             return ret;
yading@11:         }
yading@11:         e0 = make_eval_expr(c == '*' ? e_mul : e_div, 1, e1, e2);
yading@11:         if (!e0) {
yading@11:             av_expr_free(e1);
yading@11:             av_expr_free(e2);
yading@11:             return AVERROR(ENOMEM);
yading@11:         }
yading@11:     }
yading@11:     *e = e0;
yading@11:     return 0;
yading@11: }
yading@11: 
yading@11: static int parse_subexpr(AVExpr **e, Parser *p)
yading@11: {
yading@11:     int ret;
yading@11:     AVExpr *e0, *e1, *e2;
yading@11:     if ((ret = parse_term(&e0, p)) < 0)
yading@11:         return ret;
yading@11:     while (*p->s == '+' || *p->s == '-') {
yading@11:         e1 = e0;
yading@11:         if ((ret = parse_term(&e2, p)) < 0) {
yading@11:             av_expr_free(e1);
yading@11:             return ret;
yading@11:         }
yading@11:         e0 = make_eval_expr(e_add, 1, e1, e2);
yading@11:         if (!e0) {
yading@11:             av_expr_free(e1);
yading@11:             av_expr_free(e2);
yading@11:             return AVERROR(ENOMEM);
yading@11:         }
yading@11:     };
yading@11: 
yading@11:     *e = e0;
yading@11:     return 0;
yading@11: }
yading@11: 
yading@11: static int parse_expr(AVExpr **e, Parser *p)
yading@11: {
yading@11:     int ret;
yading@11:     AVExpr *e0, *e1, *e2;
yading@11:     if (p->stack_index <= 0) //protect against stack overflows
yading@11:         return AVERROR(EINVAL);
yading@11:     p->stack_index--;
yading@11: 
yading@11:     if ((ret = parse_subexpr(&e0, p)) < 0)
yading@11:         return ret;
yading@11:     while (*p->s == ';') {
yading@11:         p->s++;
yading@11:         e1 = e0;
yading@11:         if ((ret = parse_subexpr(&e2, p)) < 0) {
yading@11:             av_expr_free(e1);
yading@11:             return ret;
yading@11:         }
yading@11:         e0 = make_eval_expr(e_last, 1, e1, e2);
yading@11:         if (!e0) {
yading@11:             av_expr_free(e1);
yading@11:             av_expr_free(e2);
yading@11:             return AVERROR(ENOMEM);
yading@11:         }
yading@11:     };
yading@11: 
yading@11:     p->stack_index++;
yading@11:     *e = e0;
yading@11:     return 0;
yading@11: }
yading@11: 
yading@11: static int verify_expr(AVExpr *e)
yading@11: {
yading@11:     if (!e) return 0;
yading@11:     switch (e->type) {
yading@11:         case e_value:
yading@11:         case e_const: return 1;
yading@11:         case e_func0:
yading@11:         case e_func1:
yading@11:         case e_squish:
yading@11:         case e_ld:
yading@11:         case e_gauss:
yading@11:         case e_isnan:
yading@11:         case e_isinf:
yading@11:         case e_floor:
yading@11:         case e_ceil:
yading@11:         case e_trunc:
yading@11:         case e_sqrt:
yading@11:         case e_not:
yading@11:         case e_random:
yading@11:             return verify_expr(e->param[0]) && !e->param[1];
yading@11:         case e_print:
yading@11:             return verify_expr(e->param[0])
yading@11:                    && (!e->param[1] || verify_expr(e->param[1]));
yading@11:         case e_if:
yading@11:         case e_ifnot:
yading@11:         case e_taylor:
yading@11:             return verify_expr(e->param[0]) && verify_expr(e->param[1])
yading@11:                    && (!e->param[2] || verify_expr(e->param[2]));
yading@11:         case e_between:
yading@11:             return verify_expr(e->param[0]) &&
yading@11:                    verify_expr(e->param[1]) &&
yading@11:                    verify_expr(e->param[2]);
yading@11:         default: return verify_expr(e->param[0]) && verify_expr(e->param[1]) && !e->param[2];
yading@11:     }
yading@11: }
yading@11: 
yading@11: int av_expr_parse(AVExpr **expr, const char *s,
yading@11:                   const char * const *const_names,
yading@11:                   const char * const *func1_names, double (* const *funcs1)(void *, double),
yading@11:                   const char * const *func2_names, double (* const *funcs2)(void *, double, double),
yading@11:                   int log_offset, void *log_ctx)
yading@11: {
yading@11:     Parser p = { 0 };
yading@11:     AVExpr *e = NULL;
yading@11:     char *w = av_malloc(strlen(s) + 1);
yading@11:     char *wp = w;
yading@11:     const char *s0 = s;
yading@11:     int ret = 0;
yading@11: 
yading@11:     if (!w)
yading@11:         return AVERROR(ENOMEM);
yading@11: 
yading@11:     while (*s)
yading@11:         if (!av_isspace(*s++)) *wp++ = s[-1];
yading@11:     *wp++ = 0;
yading@11: 
yading@11:     p.class      = &class;
yading@11:     p.stack_index=100;
yading@11:     p.s= w;
yading@11:     p.const_names = const_names;
yading@11:     p.funcs1      = funcs1;
yading@11:     p.func1_names = func1_names;
yading@11:     p.funcs2      = funcs2;
yading@11:     p.func2_names = func2_names;
yading@11:     p.log_offset = log_offset;
yading@11:     p.log_ctx    = log_ctx;
yading@11: 
yading@11:     if ((ret = parse_expr(&e, &p)) < 0)
yading@11:         goto end;
yading@11:     if (*p.s) {
yading@11:         av_expr_free(e);
yading@11:         av_log(&p, AV_LOG_ERROR, "Invalid chars '%s' at the end of expression '%s'\n", p.s, s0);
yading@11:         ret = AVERROR(EINVAL);
yading@11:         goto end;
yading@11:     }
yading@11:     if (!verify_expr(e)) {
yading@11:         av_expr_free(e);
yading@11:         ret = AVERROR(EINVAL);
yading@11:         goto end;
yading@11:     }
yading@11:     e->var= av_mallocz(sizeof(double) *VARS);
yading@11:     *expr = e;
yading@11: end:
yading@11:     av_free(w);
yading@11:     return ret;
yading@11: }
yading@11: 
yading@11: double av_expr_eval(AVExpr *e, const double *const_values, void *opaque)
yading@11: {
yading@11:     Parser p = { 0 };
yading@11:     p.var= e->var;
yading@11: 
yading@11:     p.const_values = const_values;
yading@11:     p.opaque     = opaque;
yading@11:     return eval_expr(&p, e);
yading@11: }
yading@11: 
yading@11: int av_expr_parse_and_eval(double *d, const char *s,
yading@11:                            const char * const *const_names, const double *const_values,
yading@11:                            const char * const *func1_names, double (* const *funcs1)(void *, double),
yading@11:                            const char * const *func2_names, double (* const *funcs2)(void *, double, double),
yading@11:                            void *opaque, int log_offset, void *log_ctx)
yading@11: {
yading@11:     AVExpr *e = NULL;
yading@11:     int ret = av_expr_parse(&e, s, const_names, func1_names, funcs1, func2_names, funcs2, log_offset, log_ctx);
yading@11: 
yading@11:     if (ret < 0) {
yading@11:         *d = NAN;
yading@11:         return ret;
yading@11:     }
yading@11:     *d = av_expr_eval(e, const_values, opaque);
yading@11:     av_expr_free(e);
yading@11:     return isnan(*d) ? AVERROR(EINVAL) : 0;
yading@11: }
yading@11: 
yading@11: #ifdef TEST
yading@11: #include <string.h>
yading@11: 
yading@11: static const double const_values[] = {
yading@11:     M_PI,
yading@11:     M_E,
yading@11:     0
yading@11: };
yading@11: 
yading@11: static const char *const const_names[] = {
yading@11:     "PI",
yading@11:     "E",
yading@11:     0
yading@11: };
yading@11: 
yading@11: int main(int argc, char **argv)
yading@11: {
yading@11:     int i;
yading@11:     double d;
yading@11:     const char *const *expr;
yading@11:     static const char *const exprs[] = {
yading@11:         "",
yading@11:         "1;2",
yading@11:         "-20",
yading@11:         "-PI",
yading@11:         "+PI",
yading@11:         "1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)",
yading@11:         "80G/80Gi",
yading@11:         "1k",
yading@11:         "1Gi",
yading@11:         "1gi",
yading@11:         "1GiFoo",
yading@11:         "1k+1k",
yading@11:         "1Gi*3foo",
yading@11:         "foo",
yading@11:         "foo(",
yading@11:         "foo()",
yading@11:         "foo)",
yading@11:         "sin",
yading@11:         "sin(",
yading@11:         "sin()",
yading@11:         "sin)",
yading@11:         "sin 10",
yading@11:         "sin(1,2,3)",
yading@11:         "sin(1 )",
yading@11:         "1",
yading@11:         "1foo",
yading@11:         "bar + PI + E + 100f*2 + foo",
yading@11:         "13k + 12f - foo(1, 2)",
yading@11:         "1gi",
yading@11:         "1Gi",
yading@11:         "st(0, 123)",
yading@11:         "st(1, 123); ld(1)",
yading@11:         "lte(0, 1)",
yading@11:         "lte(1, 1)",
yading@11:         "lte(1, 0)",
yading@11:         "lt(0, 1)",
yading@11:         "lt(1, 1)",
yading@11:         "gt(1, 0)",
yading@11:         "gt(2, 7)",
yading@11:         "gte(122, 122)",
yading@11:         /* compute 1+2+...+N */
yading@11:         "st(0, 1); while(lte(ld(0), 100), st(1, ld(1)+ld(0));st(0, ld(0)+1)); ld(1)",
yading@11:         /* compute Fib(N) */
yading@11:         "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)",
yading@11:         "while(0, 10)",
yading@11:         "st(0, 1); while(lte(ld(0),100), st(1, ld(1)+ld(0)); st(0, ld(0)+1))",
yading@11:         "isnan(1)",
yading@11:         "isnan(NAN)",
yading@11:         "isnan(INF)",
yading@11:         "isinf(1)",
yading@11:         "isinf(NAN)",
yading@11:         "isinf(INF)",
yading@11:         "floor(NAN)",
yading@11:         "floor(123.123)",
yading@11:         "floor(-123.123)",
yading@11:         "trunc(123.123)",
yading@11:         "trunc(-123.123)",
yading@11:         "ceil(123.123)",
yading@11:         "ceil(-123.123)",
yading@11:         "sqrt(1764)",
yading@11:         "isnan(sqrt(-1))",
yading@11:         "not(1)",
yading@11:         "not(NAN)",
yading@11:         "not(0)",
yading@11:         "6.0206dB",
yading@11:         "-3.0103dB",
yading@11:         "pow(0,1.23)",
yading@11:         "pow(PI,1.23)",
yading@11:         "PI^1.23",
yading@11:         "pow(-1,1.23)",
yading@11:         "if(1, 2)",
yading@11:         "if(1, 1, 2)",
yading@11:         "if(0, 1, 2)",
yading@11:         "ifnot(0, 23)",
yading@11:         "ifnot(1, NaN) + if(0, 1)",
yading@11:         "ifnot(1, 1, 2)",
yading@11:         "ifnot(0, 1, 2)",
yading@11:         "taylor(1, 1)",
yading@11:         "taylor(eq(mod(ld(1),4),1)-eq(mod(ld(1),4),3), PI/2, 1)",
yading@11:         "root(sin(ld(0))-1, 2)",
yading@11:         "root(sin(ld(0))+6+sin(ld(0)/12)-log(ld(0)), 100)",
yading@11:         "7000000B*random(0)",
yading@11:         "squish(2)",
yading@11:         "gauss(0.1)",
yading@11:         "hypot(4,3)",
yading@11:         "gcd(30,55)*print(min(9,1))",
yading@11:         "bitor(42, 12)",
yading@11:         "bitand(42, 12)",
yading@11:         "bitand(NAN, 1)",
yading@11:         "between(10, -3, 10)",
yading@11:         "between(-4, -2, -1)",
yading@11:         "between(1,2)",
yading@11:         NULL
yading@11:     };
yading@11: 
yading@11:     for (expr = exprs; *expr; expr++) {
yading@11:         printf("Evaluating '%s'\n", *expr);
yading@11:         av_expr_parse_and_eval(&d, *expr,
yading@11:                                const_names, const_values,
yading@11:                                NULL, NULL, NULL, NULL, NULL, 0, NULL);
yading@11:         if (isnan(d))
yading@11:             printf("'%s' -> nan\n\n", *expr);
yading@11:         else
yading@11:             printf("'%s' -> %f\n\n", *expr, d);
yading@11:     }
yading@11: 
yading@11:     av_expr_parse_and_eval(&d, "1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)",
yading@11:                            const_names, const_values,
yading@11:                            NULL, NULL, NULL, NULL, NULL, 0, NULL);
yading@11:     printf("%f == 12.7\n", d);
yading@11:     av_expr_parse_and_eval(&d, "80G/80Gi",
yading@11:                            const_names, const_values,
yading@11:                            NULL, NULL, NULL, NULL, NULL, 0, NULL);
yading@11:     printf("%f == 0.931322575\n", d);
yading@11: 
yading@11:     if (argc > 1 && !strcmp(argv[1], "-t")) {
yading@11:         for (i = 0; i < 1050; i++) {
yading@11:             START_TIMER;
yading@11:             av_expr_parse_and_eval(&d, "1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)",
yading@11:                                    const_names, const_values,
yading@11:                                    NULL, NULL, NULL, NULL, NULL, 0, NULL);
yading@11:             STOP_TIMER("av_expr_parse_and_eval");
yading@11:         }
yading@11:     }
yading@11: 
yading@11:     return 0;
yading@11: }
yading@11: #endif