From 5d8375007754101ff2889d0e79486c8f9b7cf5ab Mon Sep 17 00:00:00 2001
From: Rob Mensching <rob@firegiant.com>
Date: Sun, 3 Sep 2017 11:22:38 -0700
Subject: Initial commit

---
 src/dutil/perfutil.cpp | 67 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 67 insertions(+)
 create mode 100644 src/dutil/perfutil.cpp

(limited to 'src/dutil/perfutil.cpp')

diff --git a/src/dutil/perfutil.cpp b/src/dutil/perfutil.cpp
new file mode 100644
index 00000000..5c4e0774
--- /dev/null
+++ b/src/dutil/perfutil.cpp
@@ -0,0 +1,67 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
+
+#include "precomp.h"
+
+static BOOL vfHighPerformanceCounter = TRUE;   // assume the system has a high performance counter
+static double vdFrequency = 1;
+
+
+/********************************************************************
+ PerfInitialize - initializes internal static variables
+
+********************************************************************/
+extern "C" void DAPI PerfInitialize(
+    )
+{
+    LARGE_INTEGER liFrequency = { };
+
+    //
+    // check for high perf counter
+    //
+    if (!::QueryPerformanceFrequency(&liFrequency))
+    {
+        vfHighPerformanceCounter = FALSE;
+        vdFrequency = 1000;  // ticks are measured in milliseconds
+    }
+    else
+        vdFrequency = static_cast<double>(liFrequency.QuadPart);
+}
+
+
+/********************************************************************
+ PerfClickTime - resets the clicker, or returns elapsed time since last call
+
+ NOTE: if pliElapsed is NULL, resets the elapsed time
+       if pliElapsed is not NULL, returns perf number since last call to PerfClickTime()
+********************************************************************/
+extern "C" void DAPI PerfClickTime(
+    __out_opt LARGE_INTEGER* pliElapsed
+    )
+{
+    static LARGE_INTEGER liStart = { };
+    LARGE_INTEGER* pli = pliElapsed;
+
+    if (!pli)  // if elapsed time time was not requested, reset the start time
+        pli = &liStart;
+
+    if (vfHighPerformanceCounter)
+        ::QueryPerformanceCounter(pli);
+    else
+        pli->QuadPart = ::GetTickCount();
+
+    if (pliElapsed)
+        pliElapsed->QuadPart -= liStart.QuadPart;
+}
+
+
+/********************************************************************
+ PerfConvertToSeconds - converts perf number to seconds
+
+********************************************************************/
+extern "C" double DAPI PerfConvertToSeconds(
+    __in const LARGE_INTEGER* pli
+    )
+{
+    Assert(0 < vdFrequency);
+    return pli->QuadPart / vdFrequency;
+}
-- 
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