cds/os/win/timer.h

   1 //$$CDS-header$$
   2
   3 #ifndef __CDS_OS_WIN_TIMER_H
   4 #define __CDS_OS_WIN_TIMER_H
   5
   6 #ifndef __CDS_OS_TIMER_H
   7 #   error "<cds/os/timer.h> must be included"
   8 #endif
   9
  10 #include <windows.h>
  11
  12 //@cond none
  13 namespace cds { namespace OS {
  14     CDS_CXX11_INLINE_NAMESPACE namespace Win32 {
  15
  16         /// High resolution timer
  17         /**
  18             Implementation of high resolution timer for Windows platforms.
  19             The implementation build on QueryPerformanceCounter API.
  20         */
  21         class Timer {
  22         public:
  23             typedef LARGE_INTEGER    native_timer_type        ;    ///< Native timer type
  24             typedef long long        native_duration_type    ;    ///< Native duration type
  25
  26         private:
  27             native_timer_type    m_nFrequency;
  28             native_timer_type    m_nStart;
  29
  30         public:
  31             Timer()
  32             {
  33                 ::QueryPerformanceFrequency( &m_nFrequency );
  34                 current( m_nStart );
  35             }
  36
  37             /// Places into \p tmr the current time in native Windows format
  38             static void current( native_timer_type& tmr )
  39             {
  40                 ::QueryPerformanceCounter( &tmr );
  41             }
  42
  43             /// Returns current time in native Windows format
  44             static native_timer_type current()
  45             {
  46                 native_timer_type    tmr;
  47                 current(tmr);
  48                 return tmr;
  49             }
  50
  51             /// Sets internal start time to current time. Returns duration from prevoius start time to current.
  52             double reset()
  53             {
  54                 native_timer_type nCur;
  55                 current( nCur );
  56                 double dblRet = double(nCur.QuadPart - m_nStart.QuadPart) / m_nFrequency.QuadPart;
  57                 m_nStart.QuadPart = nCur.QuadPart;
  58                 return dblRet;
  59             }
  60
  61             /// Translates \p dur from native format to seconds
  62             double duration( native_duration_type dur )
  63             {
  64                 return double( dur ) / m_nFrequency.QuadPart;
  65             }
  66
  67             /// Returns duration (in seconds) from start time to current
  68             double duration()
  69             {
  70                 return duration( native_duration() );
  71             }
  72
  73             /// Returns duration (in native format) from start time to current
  74             native_duration_type    native_duration()
  75             {
  76                 native_timer_type ts;
  77                 current( ts );
  78                 return native_duration( m_nStart, ts );
  79             }
  80
  81             /// Calculates duration (in native format) between \p nEnd and \p nStart
  82             static native_duration_type    native_duration( const native_timer_type& nStart, const native_timer_type& nEnd )
  83             {
  84                 return nEnd.QuadPart - nStart.QuadPart;
  85             }
  86
  87             static unsigned long long random_seed()
  88             {
  89                 return current().QuadPart;
  90             }
  91         };
  92
  93
  94     }   // namespace Win32
  95
  96 #ifndef CDS_CXX11_INLINE_NAMESPACE_SUPPORT
  97     typedef Win32::Timer    Timer;
  98 #endif
  99
 100 }}  // namespae cds::OS
 101 //@endcond
 102
 103 #endif // #ifndef __CDS_OS_WIN_TIMER_H