[MN-dev] [mndiff]: r121 - trunk/noe/random_internal.h

[michael]

Author: michael
Date: Mon Nov 24 19:58:36 2008
New Revision: 121

Log:
Adding a random number generator.


Added:
   trunk/noe/random_internal.h

Added: trunk/noe/random_internal.h
==============================================================================
--- (empty file)
+++ trunk/noe/random_internal.h	Mon Nov 24 19:58:36 2008
@@ -0,0 +1,40 @@
+/*
+ *   Copyright (C) 2008 Michael Niedermayer <michaelni at gmx.at>
+ *
+ *   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; either version 2 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.
+ *
+ *   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 Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ *   This code implements the KISS99 PRNG algorithm from George Marsaglia
+ */
+
+typedef struct KISSState{
+    uint32_t z,w,jsr,jcong;
+}KISSState;
+
+static uint32_t get_random(KISSState *s){
+    s->z    = (s->z>>16) + 36969*(s->z&0xFFFF);
+    s->w    = (s->w>>16) + 18000*(s->w&0xFFFF);
+    s->jsr ^= s->jsr<<17;
+    s->jsr ^= s->jsr>>13;
+    s->jsr ^= s->jsr<< 5;
+    s->jcong= 1234567 + 69069*s->jcong; 
+    return (s->w + (s->z<<16)) ^ s->jcong) + s->jsr;
+}
+
+static void init_random(KISSState *s, uint32_t seed){
+    s->z    = 362436069 ^   seed;
+    s->w    = 521288629 ^ (987654321*seed);
+    s->jsr  = 123456789 +   seed;
+    s->jcong= 380116160 -  314159265*seed;
+}