Add possibility of using an array of precalculated pseudo random numbers to reduce processor load.

common.c

@@ -757,6 +757,8 @@ uint64_t ranarrayval() {
   ranarraynext = (ranarraynext++)%ranarraylength;
 }
 
+void r64arrayinit() { ranarrayinit(); }
+
 uint64_t ranarray64u() { return (ranarrayval()); }
 
 int64_t ranarray64i() { return (ranarrayval(&rx) >> 1); }

common.h

@@ -152,6 +152,10 @@ void r64init(uint64_t seed);
 uint64_t r64u();
 int64_t r64i();
 
+void r64arrayinit();
+uint64_t ranarray64u();
+int64_t ranarray64i();
+
 int debuglev;
 void die(char *format, ...);
 void warn(char *format, ...);

player.c

@@ -677,6 +677,8 @@ static inline void process_sample(int32_t sample, char **outp, enum sps_format_t
     }
     dither_mask -= 1;
     int64_t r = r64i();
+    // int64_t r = ranarray64i();
+    
     int64_t tpdf = (r & dither_mask) - (previous_random_number & dither_mask);
     previous_random_number = r;
     // add dither, allowing for clipping

shairport.c

@@ -858,6 +858,10 @@ int main(int argc, char **argv) {
   // initialise random number generator
 
   r64init(0);
+  
+  // initialise the randomw number array
+  
+  r64arrayinit();
 
   /* Check if we are called with -V or --version parameter */
   if (argc >= 2 && ((strcmp(argv[1], "-V") == 0) || (strcmp(argv[1], "--version") == 0))) {