ESC-108 Develop support classes for numerical collection

Stuff moved over and adapted from simulator code.  Basic, simple
counters and min/max/mean accumulators.

1 files changed, 140 insertions, 0 deletions

diff --git a/indra/newview/llsimplestat.h b/indra/newview/llsimplestat.h
new file mode 100644
index 0000000000..f8f4be0390
--- /dev/null
+++ b/indra/newview/llsimplestat.h
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+/** 
+ * @file llsimplestat.h
+ * @brief Runtime statistics accumulation.
+ *
+ * $LicenseInfo:firstyear=2010&license=viewergpl$
+ * 
+ * Copyright (c) 2010, Linden Research, Inc.
+ * 
+ * Second Life Viewer Source Code
+ * 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://secondlifegrid.net/programs/open_source/licensing/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://secondlifegrid.net/programs/open_source/licensing/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.
+ * $/LicenseInfo$
+ */
+
+#ifndef LL_SIMPLESTAT_H
+#define LL_SIMPLESTAT_H
+
+// History
+//
+// The original source for this code is the server repositories'
+// llcommon/llstat.h file.  This particular code was added after the
+// viewer/server code schism but before the effort to convert common
+// code to libraries was complete.  Rather than add to merge issues,
+// the needed code was cut'n'pasted into this new header as it isn't
+// too awful a burden.  Post-modularization, we can look at removing
+// this redundancy.
+
+
+/**
+ * @class LLSimpleStatCounter
+ * @brief Just counts events.
+ *
+ * Really not needed but have a pattern in mind in the future.
+ * Interface limits what can be done at that's just fine.
+ *
+ * *TODO:  Update/transfer unit tests
+ * Unit tests:  indra/test/llcommon_llstat_tut.cpp
+ */
+class LLSimpleStatCounter
+{
+public:
+	inline LLSimpleStatCounter()		{ reset(); }
+	// Default destructor and assignment operator are valid
+
+	inline void reset()					{ mCount = 0; }
+
+	inline U32 operator++()				{ return ++mCount; }
+
+	inline U32 getCount() const			{ return mCount; }
+		
+protected:
+	U32			mCount;
+};
+
+
+/**
+ * @class LLSimpleStatMMM
+ * @brief Templated collector of min, max and mean data for stats.
+ *
+ * Fed a stream of data samples, keeps a running account of the
+ * min, max and mean seen since construction or the last reset()
+ * call.  A freshly-constructed or reset instance returns counts
+ * and values of zero.
+ *
+ * Overflows and underflows (integer, inf or -inf) and NaN's
+ * are the caller's problem.  As is loss of precision when
+ * the running sum's exponent (when parameterized by a floating
+ * point of some type) differs from a given data sample's.
+ *
+ * Unit tests:  indra/test/llcommon_llstat_tut.cpp
+ */
+template <typename VALUE_T = F32>
+class LLSimpleStatMMM
+{
+public:
+	typedef VALUE_T Value;
+	
+public:
+	LLSimpleStatMMM()				{ reset(); }
+	// Default destructor and assignment operator are valid
+
+	/**
+	 * Resets the object returning all counts and derived
+	 * values back to zero.
+	 */
+	void reset()
+		{
+			mCount = 0;
+			mMin = Value(0);
+			mMax = Value(0);
+			mTotal = Value(0);
+		}
+
+	void record(Value v)
+		{
+			if (mCount)
+			{
+				mMin = llmin(mMin, v);
+				mMax = llmax(mMax, v);
+			}
+			else
+			{
+				mMin = v;
+				mMax = v;
+			}
+			mTotal += v;
+			++mCount;
+		}
+
+	inline U32 getCount() const		{ return mCount; }
+	inline Value getMin() const		{ return mMin; }
+	inline Value getMax() const		{ return mMax; }
+	inline Value getMean() const	{ return mCount ? mTotal / mCount : mTotal; }
+		
+protected:
+	U32			mCount;
+	Value		mMin;
+	Value		mMax;
+	Value		mTotal;
+};
+
+#endif // LL_SIMPLESTAT_H