WDL/db2val.h

   1 #ifndef _WDL_DB2VAL_H_
   2 #define _WDL_DB2VAL_H_
   3
   4 #include <math.h>
   5
   6 #define TWENTY_OVER_LN10 8.6858896380650365530225783783321
   7 #define LN10_OVER_TWENTY 0.11512925464970228420089957273422
   8 #define DB2VAL(x) exp((x)*LN10_OVER_TWENTY)
   9
  10 static inline double VAL2DB(double x)
  11 {
  12   if (x < 0.0000000298023223876953125) return -150.0;
  13   double v=log(x)*TWENTY_OVER_LN10;
  14   return v<-150.0?-150.0:v;
  15 }
  16
  17 static inline double VAL2DB_EX(double x, double mindb)
  18 {
  19   return x <= DB2VAL(mindb) ? mindb : (log(x)*TWENTY_OVER_LN10);
  20 }
  21
  22 #endif