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view src/win32/PerfTimer.cpp @ 4:5f6f2134e8ce

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author Robert McIntyre <rlm@mit.edu>
date Sat, 03 Mar 2012 10:35:58 -0600
parents f9f4f1b99eed
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     1 // CPerfTimer - a simple Win32 performance counter wrapper



     2 // by Dean Wyant dwyant@mindspring.com



     3 



     4 #include "stdafx.h"



     5 #include "PerfTimer.h"



     6 



     7 // Declare and initialize static member vars that get set only once and never change



     8 __int64 CPerfTimer::m_Freq = 0; 



     9 __int64 CPerfTimer::m_Adjust = 0; 



    10 



    11 // All functions defined inline for speed. After all, the performance counter is 



    12 // supposed to be able to time very short events fairly accurately.



    13 



    14 



    15 



    16 BOOL CPerfTimer::IsSupported()



    17 { // Returns FALSE if performance counter not supported.



    18 	// Call after constructing at least one CPerfTimer



    19 	return (m_Freq > 1);



    20 }



    21 



    22 const double CPerfTimer::Resolution()   



    23 { // Returns timer resolution in seconds



    24 	return 1.0/(double)m_Freq; 



    25 }



    26 



    27 const double CPerfTimer::Resolutionms() 



    28 { // Returns timer resolution in milliseconds



    29 	return 1000.0/(double)m_Freq; 



    30 }



    31 



    32 const double CPerfTimer::Resolutionus() 



    33 { // Returns timer resolution in microseconds



    34 	return 1000000.0/(double)m_Freq; 



    35 }