/*
* simple arithmetic expression evaluator
*
- * Copyright (c) 2002 Michael Niedermayer <michaelni@gmx.at>
+ * Copyright (c) 2002-2006 Michael Niedermayer <michaelni@gmx.at>
+ * Copyright (c) 2006 Oded Shimon <ods15@ods15.dyndns.org>
*
* This file is part of FFmpeg.
*
* You should have received a copy of the GNU Lesser General Public
* 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 "eval.h"
#include <stdio.h>
#include <stdlib.h>
typedef struct Parser{
int stack_index;
char *s;
- double *const_value;
- const char **const_name; // NULL terminated
+ const double *const_value;
+ const char * const *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 char **func2_name; // NULL terminated
void *opaque;
- char **error;
+ const char **error;
+#define VARS 10
+ double var[VARS];
} Parser;
-static double evalExpression(Parser *p);
-
-static int8_t si_prefixes['z' - 'E' + 1]={
+static const int8_t si_prefixes['z' - 'E' + 1]={
['y'-'E']= -24,
['z'-'E']= -21,
['a'-'E']= -18,
if(*next=='B') {
d*=8;
- *next++;
+ next++;
}
}
/* if requested, fill in tail with the position after the last parsed
return 1;
}
-static double evalPrimary(Parser *p){
- double d, d2=NAN;
+struct ff_expr_s {
+ 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;
+ AVEvalExpr * param[2];
+};
+
+static double eval_expr(Parser * p, AVEvalExpr * 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 AVEvalExpr * parse_expr(Parser *p);
+
+void ff_eval_free(AVEvalExpr * e) {
+ if (!e) return;
+ ff_eval_free(e->param[0]);
+ ff_eval_free(e->param[1]);
+ av_freep(&e);
+}
+
+static AVEvalExpr * parse_primary(Parser *p) {
+ AVEvalExpr * d = av_mallocz(sizeof(AVEvalExpr));
char *next= p->s;
int i;
/* 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){
- *p->error = "missing (";
+ *p->error = "undefined constant or missing (";
p->s= next;
- return NAN;
+ ff_eval_free(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_eval_free(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] != ')'){
*p->error = "missing )";
- return NAN;
+ ff_eval_free(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" ) ) { AVEvalExpr * tmp = d->param[1]; d->param[1] = d->param[0]; d->param[0] = tmp; d->type = e_gt; }
+ else if( strmatch(next, "lt" ) ) { AVEvalExpr * 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;
}
}
*p->error = "unknown function";
- return NAN;
+ ff_eval_free(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 AVEvalExpr * new_eval_expr(int type, int value, AVEvalExpr *p0, AVEvalExpr *p1){
+ AVEvalExpr * e = av_mallocz(sizeof(AVEvalExpr));
+ e->type =type ;
+ e->value =value ;
+ e->param[0] =p0 ;
+ e->param[1] =p1 ;
+ return e;
+}
+
+static AVEvalExpr * parse_pow(Parser *p, int *sign){
+ *sign= (*p->s == '+') - (*p->s == '-');
+ p->s += *sign&1;
+ return parse_primary(p);
}
-static double evalFactor(Parser *p){
- double ret= evalPow(p);
+static AVEvalExpr * parse_factor(Parser *p){
+ int sign, sign2;
+ AVEvalExpr * 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->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 AVEvalExpr * parse_term(Parser *p){
+ AVEvalExpr * 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));
}
- return ret;
+ return e;
}
-static double evalExpression(Parser *p){
- double ret= 0;
+static AVEvalExpr * parse_subexpr(Parser *p) {
+ AVEvalExpr * e = parse_term(p);
+ while(*p->s == '+' || *p->s == '-') {
+ e= new_eval_expr(e_add, 1, e, parse_term(p));
+ };
+
+ return e;
+}
+
+static AVEvalExpr * parse_expr(Parser *p) {
+ AVEvalExpr * 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));
+ };
p->stack_index++;
- return ret;
+ return e;
+}
+
+static int verify_expr(AVEvalExpr * 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_eval2(char *s, double *const_value, const char **const_name,
+AVEvalExpr * ff_parse(const char *s, const char * const *const_name,
double (**func1)(void *, double), const char **func1_name,
- double (**func2)(void *, double, double), char **func2_name,
- void *opaque, char **error){
+ double (**func2)(void *, double, double), const char **func2_name,
+ const char **error){
Parser p;
+ AVEvalExpr * e;
+ char w[strlen(s) + 1], * wp = w;
+
+ 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.opaque = opaque;
p.error= error;
- return evalExpression(&p);
+ e = parse_expr(&p);
+ if (!verify_expr(e)) {
+ ff_eval_free(e);
+ return NULL;
+ }
+ return e;
}
-#if LIBAVCODEC_VERSION_INT < ((52<<16)+(0<<8)+0)
-attribute_deprecated double ff_eval(char *s, double *const_value, const char **const_name,
+double ff_parse_eval(AVEvalExpr * e, const double *const_value, void *opaque) {
+ Parser p;
+
+ p.const_value= const_value;
+ p.opaque = opaque;
+ return eval_expr(&p, e);
+}
+
+double ff_eval2(const char *s, const double *const_value, const char * const *const_name,
double (**func1)(void *, double), const char **func1_name,
- double (**func2)(void *, double, double), char **func2_name,
- void *opaque){
- char *error=NULL;
- double ret;
- ret = ff_eval2(s, const_value, const_name, func1, func1_name, func2, func2_name, opaque, &error);
- if (error)
- av_log(NULL, AV_LOG_ERROR, "Error evaluating \"%s\": %s\n", s, error);
- return ret;
+ double (**func2)(void *, double, double), const char **func2_name,
+ void *opaque, const char **error){
+ AVEvalExpr * e = ff_parse(s, const_name, func1, func1_name, func2, func2_name, error);
+ double d;
+ if (!e) return NAN;
+ d = ff_parse_eval(e, const_value, opaque);
+ ff_eval_free(e);
+ return d;
}
-#endif
#ifdef TEST
#undef printf
"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_eval2("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_eval2("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_eval2("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_eval2")
}
+ return 0;
}
#endif
projects / ffmpeg / blobdiff