1 files changed, 88 insertions, 0 deletions

diff --git a/linden/indra/llmath/llrand.h b/linden/indra/llmath/llrand.h
new file mode 100644
index 0000000..db9f353
--- /dev/null
+++ b/linden/indra/llmath/llrand.h
@@ -0,0 +1,88 @@
+/** 
+ * @file llrand.h
+ * @brief Some useful math functions.
+ *
+ * Copyright (c) 2000-2007, Linden Research, Inc.
+ * 
+ * The source code in this file ("Source Code") is provided by Linden Lab
+ * to you under the terms of the GNU General Public License, version 2.0
+ * ("GPL"), unless you have obtained a separate licensing agreement
+ * ("Other License"), formally executed by you and Linden Lab.  Terms of
+ * the GPL can be found in doc/GPL-license.txt in this distribution, or
+ * online at http://secondlife.com/developers/opensource/gplv2
+ * 
+ * There are special exceptions to the terms and conditions of the GPL as
+ * it is applied to this Source Code. View the full text of the exception
+ * in the file doc/FLOSS-exception.txt in this software distribution, or
+ * online at http://secondlife.com/developers/opensource/flossexception
+ * 
+ * By copying, modifying or distributing this software, you acknowledge
+ * that you have read and understood your obligations described above,
+ * and agree to abide by those obligations.
+ * 
+ * ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
+ * WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
+ * COMPLETENESS OR PERFORMANCE.
+ */
+
+#ifndef LL_LLRAND_H
+#define LL_LLRAND_H
+
+// As long as you #include "llviewerprecompiledheaders.h", 
+// you can use "gLindenLabRandomNumber.llfrand( range );" which returns a
+// random number F32 ranging from 0.0f to range. 
+// -Ventrella - Sept 30, 2005
+
+// Slams Intel processors into Single Precision FP mode
+// (which is not any faster on modern hardware)
+void slamFPCW( void );
+
+class LLRand
+{
+public:
+        LLRand(U32 seed) : mSeed(seed) {}
+        ~LLRand() {}
+
+        void seed(U32 seed) { mSeed = seed; }
+
+        U32  llrand()   
+        { 
+                mSeed = U64L(1664525) * mSeed + U64L(1013904223); 
+                return (U32)mSeed; 
+        }
+
+        U32  llrand(U32 val)    
+        { 
+                mSeed = U64L(1664525) * mSeed + U64L(1013904223); 
+                return (U32)(mSeed) % val; 
+        }
+
+        // val is the maximum
+        F32  llfrand(F32 val)
+        {
+                const U32 FP_ONE  = 0x3f800000;
+                const U32 FP_MASK = 0x007fffff;
+                U32 ir = llrand();
+
+                ir = FP_ONE | (FP_MASK & ir);
+                
+                // generate random float
+                F32     fr = (*(F32 *)&ir);
+
+                // correct to [0..1)
+                fr -= 1.f;
+
+                fr *= val;
+
+                return fr;
+        }
+        
+public:
+        U64 mSeed;
+};
+
+F32     frand(F32 val);
+
+extern LLRand   gLindenLabRandomNumber;
+
+#endif