diff options
author | Michael Niedermayer <michaelni@gmx.at> | 2005-01-15 23:04:41 +0300 |
---|---|---|
committer | Michael Niedermayer <michaelni@gmx.at> | 2005-01-15 23:04:41 +0300 |
commit | 67e11730fc2ef111055d6588ddc115f4de3cf7f2 (patch) | |
tree | 95cd3e7cd1d072a9ded4d0e9eb69eab2900d6848 /libavcodec/eval.c | |
parent | b349fde101d5f5296e70fef6992afcbcfc4ba2c0 (diff) |
simplify
Originally committed as revision 3841 to svn://svn.ffmpeg.org/ffmpeg/trunk
Diffstat (limited to 'libavcodec/eval.c')
-rw-r--r-- | libavcodec/eval.c | 129 |
1 files changed, 42 insertions, 87 deletions
diff --git a/libavcodec/eval.c b/libavcodec/eval.c index 257d969e97..4e1e8a3a34 100644 --- a/libavcodec/eval.c +++ b/libavcodec/eval.c @@ -42,10 +42,7 @@ #define M_PI 3.14159265358979323846 #endif -#define STACK_SIZE 100 - typedef struct Parser{ - double stack[STACK_SIZE]; int stack_index; char *s; double *const_value; @@ -57,25 +54,7 @@ typedef struct Parser{ void *opaque; } Parser; -static void evalExpression(Parser *p); - -static void push(Parser *p, double d){ - if(p->stack_index+1>= STACK_SIZE){ - av_log(NULL, AV_LOG_ERROR, "stack overflow in the parser\n"); - return; - } - p->stack[ p->stack_index++ ]= d; -//printf("push %f\n", d); fflush(stdout); -} - -static double pop(Parser *p){ - if(p->stack_index<=0){ - av_log(NULL, AV_LOG_ERROR, "stack underflow in the parser\n"); - return NAN; - } -//printf("pop\n"); fflush(stdout); - return p->stack[ --p->stack_index ]; -} +static double evalExpression(Parser *p); static int strmatch(const char *s, const char *prefix){ int i; @@ -85,7 +64,7 @@ static int strmatch(const char *s, const char *prefix){ return 1; } -static void evalPrimary(Parser *p){ +static double evalPrimary(Parser *p){ double d, d2=NAN; char *next= p->s; int i; @@ -93,36 +72,32 @@ 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 && 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){ av_log(NULL, AV_LOG_ERROR, "Parser: missing ( in \"%s\"\n", next); - return; + return NAN; } p->s++; // "(" - evalExpression(p); - d= pop(p); + d= evalExpression(p); if(p->s[0]== ','){ p->s++; // "," - evalExpression(p); - d2= pop(p); + d2= evalExpression(p); } if(p->s[0] != ')'){ av_log(NULL, AV_LOG_ERROR, "Parser: missing ) in \"%s\"\n", next); - return; + return NAN; } p->s++; // ")" @@ -144,92 +119,73 @@ static void evalPrimary(Parser *p){ 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{ 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); - goto push_ret; + 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); - goto push_ret; + return p->func2[i](p->opaque, d, d2); } } av_log(NULL, AV_LOG_ERROR, "Parser: unknown function in \"%s\"\n", next); - return; + return NAN; } -push_ret: - push(p, d); + return d; } -static void evalPow(Parser *p){ - int neg= 0; +static double evalPow(Parser *p){ if(p->s[0]=='+') p->s++; if(p->s[0]=='-'){ - neg= 1; - p->s++; - } - - if(p->s[0]=='('){ p->s++; - evalExpression(p); - - if(p->s[0]!=')') - av_log(NULL, AV_LOG_ERROR, "Parser: missing )\n"); - p->s++; - }else{ - evalPrimary(p); - } - - if(neg) push(p, -pop(p)); + return -evalPrimary(p); + }else + return evalPrimary(p); } -static void evalFactor(Parser *p){ - evalPow(p); +static double evalFactor(Parser *p){ + double ret= evalPow(p); while(p->s[0]=='^'){ - double d; - 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; - 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--; + + ret= evalTerm(p); + while(p->s[0]=='+' || p->s[0]=='-'){ + if(*p->s++ == '+') ret+= evalTerm(p); + else ret-= evalTerm(p); } + + p->stack_index++; + + return ret; } double ff_eval(char *s, double *const_value, const char **const_name, @@ -238,7 +194,7 @@ double ff_eval(char *s, double *const_value, const char **const_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; @@ -248,8 +204,7 @@ double ff_eval(char *s, double *const_value, const char **const_name, p.func2_name = func2_name; p.opaque = opaque; - evalExpression(&p); - return pop(&p); + return evalExpression(&p); } #ifdef TEST |