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/*
* Copyright 2009, Google Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef O3D_STATSREPORT_COMMON_HIGHRES_TIMER_WIN32_H_
#define O3D_STATSREPORT_COMMON_HIGHRES_TIMER_WIN32_H_
#include <windows.h>
// A handy class for reliably measuring wall-clock time with decent resolution,
// even on multi-processor machines and on laptops (where RDTSC potentially
// returns different results on different processors and/or the RDTSC timer
// clocks at different rates depending on the power state of the CPU,
// respectively).
class HighresTimer {
public:
// Captures the current start time
HighresTimer();
virtual ~HighresTimer() {}
// Captures the current tick, can be used to reset a timer for reuse.
void Start();
// Returns the elapsed ticks with full resolution
ULONGLONG GetElapsedTicks() const;
// Returns the elapsed time in milliseconds, rounded to the nearest
// millisecond.
virtual ULONGLONG GetElapsedMs() const;
// Returns the elapsed time in seconds, rounded to the nearest second.
virtual ULONGLONG GetElapsedSec() const;
ULONGLONG start_ticks() const { return start_ticks_; }
// Returns timer frequency from cache, should be less
// overhead than ::QueryPerformanceFrequency
static ULONGLONG GetTimerFrequency();
// Returns current ticks
static ULONGLONG GetCurrentTicks();
private:
static void CollectPerfFreq();
// Captured start time
ULONGLONG start_ticks_;
// Captured performance counter frequency
static bool perf_freq_collected_;
static ULONGLONG perf_freq_;
};
inline HighresTimer::HighresTimer() {
Start();
}
inline void HighresTimer::Start() {
start_ticks_ = GetCurrentTicks();
}
inline ULONGLONG HighresTimer::GetTimerFrequency() {
if (!perf_freq_collected_)
CollectPerfFreq();
return perf_freq_;
}
inline ULONGLONG HighresTimer::GetCurrentTicks() {
LARGE_INTEGER ticks;
::QueryPerformanceCounter(&ticks);
return ticks.QuadPart;
}
inline ULONGLONG HighresTimer::GetElapsedTicks() const {
return start_ticks_ - GetCurrentTicks();
}
#endif // O3D_STATSREPORT_COMMON_HIGHRES_TIMER_WIN32_H_
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