From: Florian Forster <octo@collectd.org>
Date: Sun, 24 Mar 2013 13:21:27 +0000 (+0100)
Subject: rrdtool plugin: Use cdrand_range() for the random variation.
X-Git-Tag: collectd-5.3.0~18
X-Git-Url: https://git.verplant.org/?a=commitdiff_plain;h=639cdb38830b206598d99bd22898adcdba2877a3;p=collectd.git

rrdtool plugin: Use cdrand_range() for the random variation.
---

diff --git a/src/rrdtool.c b/src/rrdtool.c
index e7c48c0e..2c80762e 100644
--- a/src/rrdtool.c
+++ b/src/rrdtool.c
@@ -1,6 +1,6 @@
 /**
  * collectd - src/rrdtool.c
- * Copyright (C) 2006-2008  Florian octo Forster
+ * Copyright (C) 2006-2013  Florian octo Forster
  * Copyright (C) 2008-2008  Sebastian Harl
  * Copyright (C) 2009       Mariusz Gronczewski
  *
@@ -18,7 +18,7 @@
  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  *
  * Authors:
- *   Florian octo Forster <octo at verplant.org>
+ *   Florian octo Forster <octo at collectd.org>
  *   Sebastian Harl <sh at tokkee.org>
  *   Mariusz Gronczewski <xani666 at gmail.com>
  **/
@@ -27,6 +27,7 @@
 #include "plugin.h"
 #include "common.h"
 #include "utils_avltree.h"
+#include "utils_random.h"
 #include "utils_rrdcreate.h"
 
 #include <rrd.h>
@@ -655,11 +656,8 @@ static int rrd_cache_flush_identifier (cdtime_t timeout,
 
 static int64_t rrd_get_random_variation (void)
 {
-  double dbl_timeout;
-  cdtime_t ctm_timeout;
-  double rand_fact;
-  _Bool negative;
-  int64_t ret;
+  long min;
+  long max;
 
   if (random_timeout <= 0)
     return (0);
@@ -672,20 +670,10 @@ static int64_t rrd_get_random_variation (void)
 	  random_timeout = cache_timeout;
   }
 
-  /* This seems a bit complicated, but "random_timeout" is likely larger than
-   * RAND_MAX, so we can't simply use modulo here. */
-  dbl_timeout = CDTIME_T_TO_DOUBLE (random_timeout);
-  rand_fact = ((double) random ())
-    / ((double) RAND_MAX);
-  negative = (_Bool) (random () % 2);
+  max = (long) (random_timeout / 2);
+  min = max - ((long) random_timeout);
 
-  ctm_timeout = DOUBLE_TO_CDTIME_T (dbl_timeout * rand_fact);
-
-  ret = (int64_t) ctm_timeout;
-  if (negative)
-    ret *= -1;
-
-  return (ret);
+  return ((int64_t) cdrand_range (min, max));
 } /* int64_t rrd_get_random_variation */
 
 static int rrd_cache_insert (const char *filename,