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// Copyright (c) 2006-2018 Maxim Khizhinsky
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE or copy at http://www.boost.org/LICENSE_1_0.txt)
#ifndef CDSLIB_OS_WIN_TIMER_H
#define CDSLIB_OS_WIN_TIMER_H
#ifndef CDSLIB_OS_TIMER_H
# error "<cds/os/timer.h> must be included"
#endif
#ifndef NOMINMAX
# define NOMINMAX
#endif
#include <windows.h>
//@cond none
namespace cds { namespace OS {
inline namespace Win32 {
/// High resolution timer
/**
Implementation of high resolution timer for Windows platforms.
The implementation build on QueryPerformanceCounter API.
*/
class Timer {
public:
typedef LARGE_INTEGER native_timer_type ; ///< Native timer type
typedef long long native_duration_type ; ///< Native duration type
private:
native_timer_type m_nFrequency;
native_timer_type m_nStart;
public:
Timer()
{
::QueryPerformanceFrequency( &m_nFrequency );
current( m_nStart );
}
/// Places into \p tmr the current time in native Windows format
static void current( native_timer_type& tmr )
{
::QueryPerformanceCounter( &tmr );
}
/// Returns current time in native Windows format
static native_timer_type current()
{
native_timer_type tmr;
current(tmr);
return tmr;
}
/// Sets internal start time to current time. Returns duration from prevoius start time to current.
double reset()
{
native_timer_type nCur;
current( nCur );
double dblRet = double(nCur.QuadPart - m_nStart.QuadPart) / m_nFrequency.QuadPart;
m_nStart.QuadPart = nCur.QuadPart;
return dblRet;
}
/// Translates \p dur from native format to seconds
double duration( native_duration_type dur )
{
return double( dur ) / m_nFrequency.QuadPart;
}
/// Returns duration (in seconds) from start time to current
double duration()
{
return duration( native_duration());
}
/// Returns duration (in native format) from start time to current
native_duration_type native_duration()
{
native_timer_type ts;
current( ts );
return native_duration( m_nStart, ts );
}
/// Calculates duration (in native format) between \p nEnd and \p nStart
static native_duration_type native_duration( const native_timer_type& nStart, const native_timer_type& nEnd )
{
return nEnd.QuadPart - nStart.QuadPart;
}
static unsigned long long random_seed()
{
return current().QuadPart;
}
};
} // namespace Win32
}} // namespae cds::OS
//@endcond
#endif // #ifndef CDSLIB_OS_WIN_TIMER_H
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