new ratecontrol code

Originally committed as revision 862 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 241 insertions, 0 deletions

diff --git a/libavcodec/eval.c b/libavcodec/eval.c
new file mode 100644
index 0000000000..8d06f7fc8a
--- /dev/null
+++ b/libavcodec/eval.c
@@ -0,0 +1,241 @@
+/*
+ * simple arithmetic expression evaluator
+ *
+ * Copyright (c) 2002 Michael Niedermayer <michaelni@gmx.at>
+ *
+ * This library 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.
+ *
+ * This library 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
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+ /*
+ * see http://joe.hotchkiss.com/programming/eval/eval.html
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+
+#define STACK_SIZE 100
+
+typedef struct Parser{
+    double stack[STACK_SIZE];
+    int stack_index;
+    char *s;
+    double *const_value;
+    char **const_name;          // NULL terminated
+    double (**func1)(void *, double a); // NULL terminated
+    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 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){
+    int i;
+    for(i=0; prefix[i]; i++){
+        if(prefix[i] != s[i]) return 0;
+    }
+    return 1;
+}
+
+static void evalPrimary(Parser *p){
+    double d, d2=NAN;
+    char *next= p->s;
+    int i;
+
+    /* number */
+    d= strtod(p->s, &next);
+    if(next != p->s){
+        push(p, d);
+        p->s= next;
+        return;
+    }
+    
+    /* named constants */
+    for(i=0; 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;
+        }
+    }
+    
+    p->s= strchr(p->s, '(');
+    if(p->s==NULL){
+        fprintf(stderr, "Parser: missing ( in \"%s\"\n", next);
+        return;
+    }
+    p->s++; // "("
+    evalExpression(p);
+    d= pop(p);
+    p->s++; // ")" or ","
+    if(p->s[-1]== ','){
+        evalExpression(p);
+        d2= pop(p);
+        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= abs(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, "lt"    ) ) d= d > d2 ? 0.0 : 1.0;
+    else if( strmatch(next, "eq"    ) ) d= d == d2 ? 1.0 : 0.0;
+//    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;
+            }
+        }
+
+        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;
+            }
+        }
+
+        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++;
+    }
+    
+    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));
+}
+
+static void evalFactor(Parser *p){
+    evalPow(p);
+    while(p->s[0]=='^'){
+        double d;
+
+        p->s++;
+        evalPow(p);
+        d= pop(p);
+        push(p, pow(pop(p), d));
+    }
+}
+
+static void evalTerm(Parser *p){
+    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));
+    }
+}
+
+static void evalExpression(Parser *p){
+    evalTerm(p);
+    while(p->s[0]=='+' || p->s[0]=='-'){
+        int sign= p->s[0]=='-';
+        double d;
+
+        p->s++;
+        evalTerm(p);
+        d= pop(p);
+        if(sign) d= -d;
+        push(p, d + pop(p));
+    }
+}
+
+double ff_eval(char *s, double *const_value, char **const_name,
+               double (**func1)(void *, double), char **func1_name, 
+               double (**func2)(void *, double, double), char **func2_name,
+               void *opaque){
+    Parser p;
+    
+    p.stack_index=0;
+    p.s= s;
+    p.const_value= const_value;
+    p.const_name = const_name;
+    p.func1      = func1;
+    p.func1_name = func1_name;
+    p.func2      = func2;
+    p.func2_name = func2_name;
+    p.opaque     = opaque;
+    
+    evalExpression(&p);
+    return pop(&p);
+}