Common: Add Timer.h

Common/Common.vcxproj

@@ -40,6 +40,7 @@
     <ClInclude Include="Platform.h" />
     <ClInclude Include="RawString.h" />
     <ClInclude Include="StringUtil.h" />
+    <ClInclude Include="Timer.h" />
     <ClInclude Include="UnitTest.h" />
   </ItemGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />

Common/Common.vcxproj.filters

@@ -19,5 +19,6 @@
     <ClInclude Include="ControlTemplate.h" />
     <ClInclude Include="MathParser.h" />
     <ClInclude Include="UnitTest.h" />
+    <ClInclude Include="Timer.h" />
   </ItemGroup>
 </Project>

Common/Timer.h

@@ -0,0 +1,56 @@
+/*
+  Copyright (C) 2013 Rainmeter Team
+
+  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.
+*/
+
+#ifndef RM_COMMON_TIMER_H_
+#define RM_COMMON_TIMER_H_
+
+#include <Windows.h>
+
+// Performs timing using the high-resolution performance counter.
+class Timer
+{
+public:
+	void Start()
+	{
+		QueryPerformanceCounter(&m_Start);
+	}
+
+	void Stop()
+	{
+		QueryPerformanceCounter(&m_Stop);
+	}
+
+	// Returns the elapsed time in milliseconds.
+	double GetElapsed() const
+	{
+		static LARGE_INTEGER s_Frequency = []()
+		{
+			LARGE_INTEGER frequency;
+			QueryPerformanceFrequency(&frequency);
+			return frequency;
+		} ();
+
+		return (m_Stop.QuadPart - m_Start.QuadPart) * 1000.0 / s_Frequency.QuadPart;
+	}
+
+private:
+	LARGE_INTEGER m_Start;
+	LARGE_INTEGER m_Stop;
+};
+
+#endif