X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavcodec%2Feval.c;h=5b0e51d627e248de3aafa5aa534ab183ceea65d2;hb=79b0b66ba07890c4f71b42d2554d73db537bec97;hp=8d06f7fc8a5ac2cf1a9e0efc8abdcab9a95f1627;hpb=3aa102be84e4fe0bd8fc8be1fc62a3e498388a10;p=ffmpeg diff --git a/libavcodec/eval.c b/libavcodec/eval.c index 8d06f7fc8a5..5b0e51d627e 100644 --- a/libavcodec/eval.c +++ b/libavcodec/eval.c @@ -15,55 +15,48 @@ * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA * */ - /* +/** + * @file eval.c + * simple arithmetic expression evaluator. + * * see http://joe.hotchkiss.com/programming/eval/eval.html */ +#include "avcodec.h" +#include "mpegvideo.h" + #include #include #include #include -#define STACK_SIZE 100 +#ifndef NAN + #define NAN 0 +#endif + +#ifndef M_PI +#define M_PI 3.14159265358979323846 +#endif typedef struct Parser{ - double stack[STACK_SIZE]; int stack_index; char *s; double *const_value; - char **const_name; // NULL terminated + const char **const_name; // NULL terminated double (**func1)(void *, double a); // NULL terminated - char **func1_name; // NULL terminated + const char **func1_name; // NULL terminated double (**func2)(void *, double a, double b); // NULL terminated char **func2_name; // NULL terminated void *opaque; } Parser; -static void evalExpression(Parser *p); - -static void push(Parser *p, double d){ - if(p->stack_index+1>= STACK_SIZE){ - fprintf(stderr, "stack overflow in the parser\n"); - return; - } - p->stack[ p->stack_index++ ]= d; -//printf("push %f\n", d); fflush(stdout); -} +static double evalExpression(Parser *p); -static double pop(Parser *p){ - if(p->stack_index<=0){ - fprintf(stderr, "stack underflow in the parser\n"); - return NAN; - } -//printf("pop\n"); fflush(stdout); - return p->stack[ --p->stack_index ]; -} - -static int strmatch(char *s, char *prefix){ +static int strmatch(const char *s, const char *prefix){ int i; for(i=0; prefix[i]; i++){ if(prefix[i] != s[i]) return 0; @@ -71,7 +64,7 @@ static int strmatch(char *s, char *prefix){ return 1; } -static void evalPrimary(Parser *p){ +static double evalPrimary(Parser *p){ double d, d2=NAN; char *next= p->s; int i; @@ -79,35 +72,35 @@ static void evalPrimary(Parser *p){ /* number */ d= strtod(p->s, &next); if(next != p->s){ - push(p, d); p->s= next; - return; + return d; } - + /* named constants */ - for(i=0; p->const_name[i]; i++){ + for(i=0; p->const_name && p->const_name[i]; i++){ if(strmatch(p->s, p->const_name[i])){ - push(p, p->const_value[i]); p->s+= strlen(p->const_name[i]); - return; + return p->const_value[i]; } } - + p->s= strchr(p->s, '('); if(p->s==NULL){ - fprintf(stderr, "Parser: missing ( in \"%s\"\n", next); - return; + av_log(NULL, AV_LOG_ERROR, "Parser: missing ( in \"%s\"\n", next); + return NAN; } p->s++; // "(" - evalExpression(p); - d= pop(p); - p->s++; // ")" or "," - if(p->s[-1]== ','){ - evalExpression(p); - d2= pop(p); - p->s++; // ")" + d= evalExpression(p); + if(p->s[0]== ','){ + p->s++; // "," + d2= evalExpression(p); } - + if(p->s[0] != ')'){ + av_log(NULL, AV_LOG_ERROR, "Parser: missing ) in \"%s\"\n", next); + return NAN; + } + 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); @@ -118,115 +111,84 @@ static void evalPrimary(Parser *p){ 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= abs(d); + 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{ - int error=1; for(i=0; p->func1_name && p->func1_name[i]; i++){ if(strmatch(next, p->func1_name[i])){ - d= p->func1[i](p->opaque, d); - error=0; - break; + return p->func1[i](p->opaque, d); } } for(i=0; p->func2_name && p->func2_name[i]; i++){ if(strmatch(next, p->func2_name[i])){ - d= p->func2[i](p->opaque, d, d2); - error=0; - break; + return p->func2[i](p->opaque, d, d2); } } - if(error){ - fprintf(stderr, "Parser: unknown function in \"%s\"\n", next); - return; - } - } - - if(p->s[-1]!= ')'){ - fprintf(stderr, "Parser: missing ) in \"%s\"\n", next); - return; - } - push(p, d); -} - -static void evalPow(Parser *p){ - int neg= 0; - if(p->s[0]=='+') p->s++; - - if(p->s[0]=='-'){ - neg= 1; - p->s++; + av_log(NULL, AV_LOG_ERROR, "Parser: unknown function in \"%s\"\n", next); + return NAN; } - - if(p->s[0]=='('){ - p->s++;; - evalExpression(p); - if(p->s[0]!=')') - fprintf(stderr, "Parser: missing )\n"); - p->s++; - }else{ - evalPrimary(p); - } - - if(neg) push(p, -pop(p)); + return d; } -static void evalFactor(Parser *p){ - evalPow(p); - while(p->s[0]=='^'){ - double d; +static double evalPow(Parser *p){ + int sign= (*p->s == '+') - (*p->s == '-'); + p->s += sign&1; + return (sign|1) * evalPrimary(p); +} +static double evalFactor(Parser *p){ + double ret= evalPow(p); + while(p->s[0]=='^'){ p->s++; - evalPow(p); - d= pop(p); - push(p, pow(pop(p), d)); + ret= pow(ret, evalPow(p)); } + return ret; } -static void evalTerm(Parser *p){ - evalFactor(p); +static double evalTerm(Parser *p){ + double ret= evalFactor(p); while(p->s[0]=='*' || p->s[0]=='/'){ - int inv= p->s[0]=='/'; - double d; - - p->s++; - evalFactor(p); - d= pop(p); - if(inv) d= 1.0/d; - push(p, d * pop(p)); + if(*p->s++ == '*') ret*= evalFactor(p); + else ret/= evalFactor(p); } + return ret; } -static void evalExpression(Parser *p){ - evalTerm(p); - while(p->s[0]=='+' || p->s[0]=='-'){ - int sign= p->s[0]=='-'; - double d; +static double evalExpression(Parser *p){ + double ret= 0; - p->s++; - evalTerm(p); - d= pop(p); - if(sign) d= -d; - push(p, d + pop(p)); - } + if(p->stack_index <= 0) //protect against stack overflows + return NAN; + p->stack_index--; + + do{ + ret += evalTerm(p); + }while(*p->s == '+' || *p->s == '-'); + + p->stack_index++; + + return ret; } -double ff_eval(char *s, double *const_value, char **const_name, - double (**func1)(void *, double), char **func1_name, +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){ Parser p; - - p.stack_index=0; + + p.stack_index=100; p.s= s; p.const_value= const_value; p.const_name = const_name; @@ -235,7 +197,30 @@ double ff_eval(char *s, double *const_value, char **const_name, p.func2 = func2; p.func2_name = func2_name; p.opaque = opaque; - - evalExpression(&p); - return pop(&p); + + return evalExpression(&p); +} + +#ifdef TEST +#undef printf +static double const_values[]={ + M_PI, + M_E, + 0 +}; +static const char *const_names[]={ + "PI", + "E", + 0 +}; +main(){ + 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)); + + 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") + } } +#endif