/*
- * simple arithmetic expression evaluator
+ * Copyright (c) 2002-2006 Michael Niedermayer <michaelni@gmx.at>
+ * Copyright (c) 2006 Oded Shimon <ods15@ods15.dyndns.org>
*
- * Copyright (c) 2002 Michael Niedermayer <michaelni@gmx.at>
+ * This file is part of FFmpeg.
*
- * This library is free software; you can redistribute it and/or
+ * FFmpeg 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 of the License, or (at your option) any later version.
+ * version 2.1 of the License, or (at your option) any later version.
*
- * This library is distributed in the hope that it will be useful,
+ * FFmpeg 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 this library; if not, write to the Free Software
+ * License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- *
*/
/**
- * @file eval.c
+ * @file libavcodec/eval.c
* simple arithmetic expression evaluator.
*
* see http://joe.hotchkiss.com/programming/eval/eval.html
*/
-#include "avcodec.h"
-#include "mpegvideo.h"
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <math.h>
-
-#ifndef NAN
- #define NAN 0.0/0.0
-#endif
-
-#ifndef M_PI
-#define M_PI 3.14159265358979323846
-#endif
+#include "libavutil/avutil.h"
+#include "eval.h"
typedef struct Parser{
int stack_index;
char *s;
- double *const_value;
- const char **const_name; // NULL terminated
- double (**func1)(void *, double a); // NULL terminated
- const char **func1_name; // NULL terminated
- double (**func2)(void *, double a, double b); // NULL terminated
- char **func2_name; // NULL terminated
+ const double *const_value;
+ const char * const *const_name; // NULL terminated
+ double (* const *func1)(void *, double a); // NULL terminated
+ const char * const *func1_name; // NULL terminated
+ double (* const *func2)(void *, double a, double b); // NULL terminated
+ const char * const *func2_name; // NULL terminated
void *opaque;
+ const char **error;
+#define VARS 10
+ double var[VARS];
} Parser;
-extern double av_strtod(const char *name, char **tail);
+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,
+};
-static double evalExpression(Parser *p);
+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 >= '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;
+}
static int strmatch(const char *s, const char *prefix){
int i;
return 1;
}
-static double evalPrimary(Parser *p){
- double d, d2=NAN;
+struct AVExpr {
+ enum {
+ e_value, e_const, e_func0, e_func1, e_func2,
+ e_squish, e_gauss, e_ld,
+ 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,
+ } 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_value[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_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 AVExpr * parse_expr(Parser *p);
+
+void ff_free_expr(AVExpr * e) {
+ if (!e) return;
+ ff_free_expr(e->param[0]);
+ ff_free_expr(e->param[1]);
+ av_freep(&e);
+}
+
+static AVExpr * parse_primary(Parser *p) {
+ AVExpr * d = av_mallocz(sizeof(AVExpr));
char *next= p->s;
int i;
+ if (!d)
+ return NULL;
+
/* number */
- d= av_strtod(p->s, &next);
+ d->value = av_strtod(p->s, &next);
if(next != p->s){
+ d->type = e_value;
p->s= next;
return d;
}
+ d->value = 1;
/* named constants */
for(i=0; p->const_name && p->const_name[i]; i++){
if(strmatch(p->s, p->const_name[i])){
p->s+= strlen(p->const_name[i]);
- return p->const_value[i];
+ d->type = e_const;
+ d->a.const_index = i;
+ return d;
}
}
p->s= strchr(p->s, '(');
if(p->s==NULL){
- av_log(NULL, AV_LOG_ERROR, "Parser: missing ( in \"%s\"\n", next);
+ *p->error = "undefined constant or missing (";
p->s= next;
- return NAN;
+ ff_free_expr(d);
+ return NULL;
}
p->s++; // "("
- d= evalExpression(p);
+ if (*next == '(') { // special case do-nothing
+ av_freep(&d);
+ d = parse_expr(p);
+ if(p->s[0] != ')'){
+ *p->error = "missing )";
+ ff_free_expr(d);
+ return NULL;
+ }
+ p->s++; // ")"
+ return d;
+ }
+ d->param[0] = parse_expr(p);
if(p->s[0]== ','){
p->s++; // ","
- d2= evalExpression(p);
+ d->param[1] = parse_expr(p);
}
if(p->s[0] != ')'){
- av_log(NULL, AV_LOG_ERROR, "Parser: missing ) in \"%s\"\n", next);
- return NAN;
+ *p->error = "missing )";
+ ff_free_expr(d);
+ return NULL;
}
p->s++; // ")"
- if( strmatch(next, "sinh" ) ) d= sinh(d);
- else if( strmatch(next, "cosh" ) ) d= cosh(d);
- else if( strmatch(next, "tanh" ) ) d= tanh(d);
- else if( strmatch(next, "sin" ) ) d= sin(d);
- else if( strmatch(next, "cos" ) ) d= cos(d);
- else if( strmatch(next, "tan" ) ) d= tan(d);
- else if( strmatch(next, "exp" ) ) d= exp(d);
- else if( strmatch(next, "log" ) ) d= log(d);
- else if( strmatch(next, "squish") ) d= 1/(1+exp(4*d));
- else if( strmatch(next, "gauss" ) ) d= exp(-d*d/2)/sqrt(2*M_PI);
- else if( strmatch(next, "abs" ) ) d= fabs(d);
- else if( strmatch(next, "max" ) ) d= d > d2 ? d : d2;
- else if( strmatch(next, "min" ) ) d= d < d2 ? d : d2;
- else if( strmatch(next, "gt" ) ) d= d > d2 ? 1.0 : 0.0;
- else if( strmatch(next, "gte" ) ) d= d >= d2 ? 1.0 : 0.0;
- else if( strmatch(next, "lt" ) ) d= d > d2 ? 0.0 : 1.0;
- else if( strmatch(next, "lte" ) ) d= d >= d2 ? 0.0 : 1.0;
- else if( strmatch(next, "eq" ) ) d= d == d2 ? 1.0 : 0.0;
- else if( strmatch(next, "(" ) ) d= d;
-// else if( strmatch(next, "l1" ) ) d= 1 + d2*(d - 1);
-// else if( strmatch(next, "sq01" ) ) d= (d >= 0.0 && d <=1.0) ? 1.0 : 0.0;
- else{
+ 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_gt; }
+ else if( strmatch(next, "lt" ) ) { AVExpr * tmp = d->param[1]; d->param[1] = d->param[0]; d->param[0] = tmp; d->type = e_gte; }
+ else if( strmatch(next, "ld" ) ) d->type = e_ld;
+ else if( strmatch(next, "st" ) ) d->type = e_st;
+ else if( strmatch(next, "while" ) ) d->type = e_while;
+ else {
for(i=0; p->func1_name && p->func1_name[i]; i++){
if(strmatch(next, p->func1_name[i])){
- return p->func1[i](p->opaque, d);
+ d->a.func1 = p->func1[i];
+ d->type = e_func1;
+ return d;
}
}
for(i=0; p->func2_name && p->func2_name[i]; i++){
if(strmatch(next, p->func2_name[i])){
- return p->func2[i](p->opaque, d, d2);
+ d->a.func2 = p->func2[i];
+ d->type = e_func2;
+ return d;
}
}
- av_log(NULL, AV_LOG_ERROR, "Parser: unknown function in \"%s\"\n", next);
- return NAN;
+ *p->error = "unknown function";
+ ff_free_expr(d);
+ return NULL;
}
return d;
}
-static double evalPow(Parser *p){
- int sign= (*p->s == '+') - (*p->s == '-');
- p->s += sign&1;
- return (sign|1) * evalPrimary(p);
+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 double evalFactor(Parser *p){
- double ret= evalPow(p);
+static AVExpr * parse_pow(Parser *p, int *sign){
+ *sign= (*p->s == '+') - (*p->s == '-');
+ p->s += *sign&1;
+ return parse_primary(p);
+}
+
+static AVExpr * parse_factor(Parser *p){
+ int sign, sign2;
+ AVExpr * e = parse_pow(p, &sign);
while(p->s[0]=='^'){
p->s++;
- ret= pow(ret, evalPow(p));
+ e= new_eval_expr(e_pow, 1, e, parse_pow(p, &sign2));
+ if (!e)
+ return NULL;
+ if (e->param[1]) e->param[1]->value *= (sign2|1);
}
- return ret;
+ if (e) e->value *= (sign|1);
+ return e;
}
-static double evalTerm(Parser *p){
- double ret= evalFactor(p);
+static AVExpr * parse_term(Parser *p){
+ AVExpr * e = parse_factor(p);
while(p->s[0]=='*' || p->s[0]=='/'){
- if(*p->s++ == '*') ret*= evalFactor(p);
- else ret/= evalFactor(p);
+ int c= *p->s++;
+ e= new_eval_expr(c == '*' ? e_mul : e_div, 1, e, parse_factor(p));
+ if (!e)
+ return NULL;
}
- return ret;
+ return e;
}
-static double evalExpression(Parser *p){
- double ret= 0;
+static AVExpr * parse_subexpr(Parser *p) {
+ AVExpr * e = parse_term(p);
+ while(*p->s == '+' || *p->s == '-') {
+ e= new_eval_expr(e_add, 1, e, parse_term(p));
+ if (!e)
+ return NULL;
+ };
+
+ return e;
+}
+
+static AVExpr * parse_expr(Parser *p) {
+ AVExpr * e;
if(p->stack_index <= 0) //protect against stack overflows
- return NAN;
+ return NULL;
p->stack_index--;
- do{
- ret += evalTerm(p);
- }while(*p->s == '+' || *p->s == '-');
+ e = parse_subexpr(p);
+
+ while(*p->s == ';') {
+ p->s++;
+ e= new_eval_expr(e_last, 1, e, parse_subexpr(p));
+ if (!e)
+ return NULL;
+ };
p->stack_index++;
- return ret;
+ return e;
+}
+
+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: return verify_expr(e->param[0]);
+ default: return verify_expr(e->param[0]) && verify_expr(e->param[1]);
+ }
}
-double ff_eval(char *s, double *const_value, const char **const_name,
- double (**func1)(void *, double), const char **func1_name,
- double (**func2)(void *, double, double), char **func2_name,
- void *opaque){
+AVExpr *ff_parse_expr(const char *s, const char * const *const_name,
+ double (* const *func1)(void *, double), const char * const *func1_name,
+ double (* const *func2)(void *, double, double), const char * const *func2_name,
+ const char **error){
Parser p;
+ AVExpr *e = NULL;
+ char *w = av_malloc(strlen(s) + 1);
+ char *wp = w;
+
+ if (!w)
+ goto end;
+
+ while (*s)
+ if (!isspace(*s++)) *wp++ = s[-1];
+ *wp++ = 0;
p.stack_index=100;
- p.s= s;
- p.const_value= const_value;
+ p.s= w;
p.const_name = const_name;
p.func1 = func1;
p.func1_name = func1_name;
p.func2 = func2;
p.func2_name = func2_name;
+ p.error= error;
+
+ e = parse_expr(&p);
+ if (!verify_expr(e)) {
+ ff_free_expr(e);
+ e = NULL;
+ }
+end:
+ av_free(w);
+ return e;
+}
+
+double ff_eval_expr(AVExpr * e, const double *const_value, void *opaque) {
+ Parser p;
+
+ p.const_value= const_value;
p.opaque = opaque;
+ return eval_expr(&p, e);
+}
- return evalExpression(&p);
+double ff_parse_and_eval_expr(const char *s, const double *const_value, const char * const *const_name,
+ double (* const *func1)(void *, double), const char * const *func1_name,
+ double (* const *func2)(void *, double, double), const char * const *func2_name,
+ void *opaque, const char **error){
+ AVExpr * e = ff_parse_expr(s, const_name, func1, func1_name, func2, func2_name, error);
+ double d;
+ if (!e) return NAN;
+ d = ff_eval_expr(e, const_value, opaque);
+ ff_free_expr(e);
+ return d;
}
#ifdef TEST
"E",
0
};
-main(){
+int main(void){
int i;
- printf("%f == 12.7\n", ff_eval("1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)", const_values, const_names, NULL, NULL, NULL, NULL, NULL));
- printf("%f == 0.931322575\n", ff_eval("80G/80Gi", const_values, const_names, NULL, NULL, NULL, NULL, NULL));
+ printf("%f == 12.7\n", ff_parse_and_eval_expr("1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)", const_values, const_names, NULL, NULL, NULL, NULL, NULL, NULL));
+ printf("%f == 0.931322575\n", ff_parse_and_eval_expr("80G/80Gi", const_values, const_names, NULL, NULL, NULL, NULL, NULL, NULL));
for(i=0; i<1050; i++){
START_TIMER
- ff_eval("1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)", const_values, const_names, NULL, NULL, NULL, NULL, NULL);
- STOP_TIMER("ff_eval")
+ ff_parse_and_eval_expr("1+(5-2)^(3-1)+1/2+sin(PI)-max(-2.2,-3.1)", const_values, const_names, NULL, NULL, NULL, NULL, NULL, NULL);
+ STOP_TIMER("ff_parse_and_eval_expr")
}
+ return 0;
}
#endif
projects / ffmpeg / blobdiff