Use c++11 mt19937_64 as random number generator.

Author: thefallentree

src/port.c

@@ -5,22 +5,22 @@
 #include <unistd.h>
 #include <sys/resource.h>
 
-/*
- * Return a pseudo-random number in the range 0 .. n-1
- */
-// FIXME: drand48 doesn't provide enough random bits for 64bit LPC int.
-long random_number(long n)
-{
-  static char called = 0;
+#include <random>
 
-  if (!called) {
-    time_t tim;
+// Returns a pseudo-random number in the range 0 .. n-1
+int64_t random_number(int64_t n)
+{
+  static bool called = 0;
+  static std::mt19937_64 engine;
 
-    time(&tim);
-    srand48(tim);
+  if(!called) {
+    std::random_device rd;
+    engine.seed(rd());
     called = 1;
-  }               /* endif */
-  return (long)(drand48() * n);
+  }
+
+  std::uniform_int_distribution<int64_t> dist(0, n-1);
+  return dist(engine);
 }
 
 /*

src/port.h

@@ -5,7 +5,7 @@
  * port.c
  */
 #ifndef _FUNC_SPEC_
-long random_number(long);
+int64_t random_number(int64_t);
 long get_current_time(void);
 const char *time_string(time_t);
 void get_usec_clock(long *, long *);