From 55431ec82f1db436938125d9d6169aab79cbd3d3 Mon Sep 17 00:00:00 2001
From: Mike Buland <eichlan@xagasoft.com>
Date: Fri, 4 May 2012 18:44:53 +0000
Subject: Two basic random number generators, Cmwc is supposed to be a pretty
 good one.

I need to get the base class and singleton interface in place.
---
 src/experimental/randombasic.cpp | 20 ++++++++++++++--
 src/experimental/randombasic.h   |  6 ++++-
 src/experimental/randomcmwc.cpp  | 52 ++++++++++++++++++++++++++++++++++++++++
 src/experimental/randomcmwc.h    | 29 ++++++++++++++++++++++
 4 files changed, 104 insertions(+), 3 deletions(-)
 create mode 100644 src/experimental/randomcmwc.cpp
 create mode 100644 src/experimental/randomcmwc.h

diff --git a/src/experimental/randombasic.cpp b/src/experimental/randombasic.cpp
index 03bf7fe..ac591be 100644
--- a/src/experimental/randombasic.cpp
+++ b/src/experimental/randombasic.cpp
@@ -8,8 +8,24 @@
 #include "bu/randombasic.h"
 
 Bu::RandomBasic::RandomBasic() :
-	c( 6364136223846793005 ),
-	m( 1442695040888963407 )
+	a( 6364136223846793005 ),
+	c( 1442695040888963407 ),
+	x( 0 )
 {
 }
 
+Bu::RandomBasic::~RandomBasic()
+{
+}
+
+void Bu::RandomBasic::seed( int32_t iSeed )
+{
+	c = iSeed;
+}
+
+int32_t Bu::RandomBasic::rand()
+{
+	x = (a*x + c);
+	return (int32_t)x;
+}
+
diff --git a/src/experimental/randombasic.h b/src/experimental/randombasic.h
index 2ba7bd3..6eab9dc 100644
--- a/src/experimental/randombasic.h
+++ b/src/experimental/randombasic.h
@@ -17,8 +17,12 @@ namespace Bu
 		RandomBasic();
 		virtual ~RandomBasic();
 
+		void seed( int32_t iSeed );
+
+		int32_t rand();
+
 	private:
-		int64_t c, m, a;
+		int64_t a, c, x;
 	};
 };
 
diff --git a/src/experimental/randomcmwc.cpp b/src/experimental/randomcmwc.cpp
new file mode 100644
index 0000000..97f7262
--- /dev/null
+++ b/src/experimental/randomcmwc.cpp
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2007-2012 Xagasoft, All rights reserved.
+ *
+ * This file is part of the libbu++ library and is released under the
+ * terms of the license contained in the file LICENSE.
+ */
+
+#include "bu/randomcmwc.h"
+
+#define PHI 0x9e3779b9
+
+RandomCmwc::RandomCmwc() :
+	q( NULL ),
+	c( 362436 )
+{
+	q = new uint32_t[4096];
+}
+
+RandomCmwc::~RandomCmwc()
+{
+	delete[] q;
+}
+
+void RandomCmwc::seed( int32_t iSeed )
+{
+	int i;
+
+	Q[0] = iSeed;
+	Q[1] = iSeed + PHI;
+	Q[2] = iSeed + PHI + PHI;
+
+	for (i = 3; i < 4096; i++)
+		Q[i] = Q[i - 3] ^ Q[i - 2] ^ PHI ^ i;	
+}
+
+int32_t RandomCmwc::rand()
+{
+	uint64_t t, a = 18782LL;
+	static uint32_t i = 4095;
+	uint32_t x, r = 0xfffffffe;
+	i = (i + 1) & 4095;
+	t = a * Q[i] + c;
+	c = (t >> 32);
+	x = t + c;
+	if( x < c )
+	{
+		x++;
+		c++;
+	}
+	return (Q[i] = r - x);
+}
+
diff --git a/src/experimental/randomcmwc.h b/src/experimental/randomcmwc.h
new file mode 100644
index 0000000..3a05383
--- /dev/null
+++ b/src/experimental/randomcmwc.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2007-2012 Xagasoft, All rights reserved.
+ *
+ * This file is part of the libbu++ library and is released under the
+ * terms of the license contained in the file LICENSE.
+ */
+#ifndef BU_RANDOM_CMWC_H
+#define BU_RANDOM_CMWC_H
+
+#include <stdint.h>
+
+namespace Bu
+{
+	class RandomCmwc
+	{
+	public:
+		RandomCmwc();
+		virtual ~RandomCmwc();
+
+		void seed( int32_t iSeed );
+
+		int32_t rand();
+
+	private:
+		uint32_t *q, c;
+	};
+};
+
+#endif
-- 
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