sn-tex: Fix indentation (remove tabs).

[sort-networks.git] / src / sn_random.c

diff --git a/src/sn_random.c b/src/sn_random.c
index 5a156d2..bd4701b 100644 (file)
--- a/src/sn_random.c
+++ b/src/sn_random.c
@@ -2,18 +2,19 @@
  * libsortnetwork - src/sn_random.c
  * Copyright (C) 2008-2010  Florian octo Forster
  *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License as published by the
- * Free Software Foundation; only version 2 of the License is applicable.
+ * 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 2.1 of the License, or (at
+ * your option) any later version.
  *
- * This program 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
- * General Public License for more details.
+ * 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 General Public License along
- * with this program; if not, write to the Free Software Foundation, Inc.,
- * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ * 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  *
  * Authors:
  *   Florian octo Forster <ff at octo.it>
@@ -39,7 +40,8 @@
 #include "sn_random.h"
 
 static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
-static unsigned int seed;
+static unsigned int seed0;
+static unsigned int seed1;
 static int have_init = 0;
 
 static int read_dev_random (void *buffer, size_t buffer_size)
@@ -50,7 +52,7 @@ static int read_dev_random (void *buffer, size_t buffer_size)
   char *buffer_position;
   size_t yet_to_read;
 
-  fd = open ("/dev/random", O_RDONLY);
+  fd = open ("/dev/urandom", O_RDONLY);
   if (fd < 0)
   {
     perror ("open");
@@ -85,27 +87,37 @@ static int read_dev_random (void *buffer, size_t buffer_size)
 
 static void do_init (void)
 {
-  int status;
+  if (have_init)
+    return;
 
-  status = read_dev_random (&seed, sizeof (seed));
-  if (status == 0)
-    have_init = 1;
+  read_dev_random (&seed0, sizeof (seed0));
+  read_dev_random (&seed1, sizeof (seed1));
+  have_init = 1;
 } /* void do_init */
 
+int sn_random_init (void)
+{
+  have_init = 0;
+  do_init ();
+
+  return (0);
+}
+
 int sn_random (void)
 {
-  int ret;
+  int r0;
+  int r1;
 
   pthread_mutex_lock (&lock);
 
-  if (have_init == 0)
-    do_init ();
+  do_init ();
 
-  ret = rand_r (&seed);
+  r0 = rand_r (&seed0);
+  r1 = rand_r (&seed1);
 
   pthread_mutex_unlock (&lock);
 
-  return (ret);
+  return (r0 ^ r1);
 } /* int sn_random */
 
 int sn_true_random (void)