1 files changed, 48 insertions, 0 deletions
diff --git a/lib/qrand.c b/lib/qrand.c
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+/* Pseudo Random Sequence
+ * Copyright (C) 2010 Chris Hall (GMCH), Highwayman
+ *
+ * This file is part of GNU Zebra.
+ *
+ * GNU Zebra 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; either version 2, or (at your
+ * option) any later version.
+ *
+ * GNU Zebra 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Zebra; see the file COPYING.  If not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include "qrand.h"
+
+/*==============================================================================
+ * Simple 32 bit random sequence.
+ */
+
+/*------------------------------------------------------------------------------
+ * Return next in the given sequence.
+ *
+ * Returns value in range 0..range-1, or 0..0x7FFF_FFFF if range == 0
+ *
+ * If range == 1, returns 0 every time !
+ */
+extern int
+qrand(qrand_seq seq, int range)
+{
+  uint64_t  r ;
+
+  r = seq->last ^ 3141592653 ;
+  r = ((r * 2650845021) + 5) & 0xFFFFFFFF ;     /* see Knuth    */
+  seq->last = r ;
+
+  if (range == 0)
+    return r >> 1 ;
+  else
+    return (r % range) ;
+} ;