catch2/include/internal/catch_timer.cpp

63 lines
2.0 KiB
C++

/*
* Created by Phil on 05/08/2013.
* Copyright 2013 Two Blue Cubes Ltd. All rights reserved.
*
* Distributed under the Boost Software License, Version 1.0. (See accompanying
* file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
*/
#include "catch_timer.h"
#include <chrono>
namespace Catch {
auto getCurrentNanosecondsSinceEpoch() -> uint64_t {
return std::chrono::duration_cast<std::chrono::nanoseconds>( std::chrono::high_resolution_clock::now().time_since_epoch() ).count();
}
auto estimateClockResolution() -> double {
uint64_t sum = 0;
static const uint64_t iterations = 1000000;
for( size_t i = 0; i < iterations; ++i ) {
uint64_t ticks;
uint64_t baseTicks = getCurrentNanosecondsSinceEpoch();
do {
ticks = getCurrentNanosecondsSinceEpoch();
}
while( ticks == baseTicks );
auto delta = ticks - baseTicks;
sum += delta;
}
// We're just taking the mean, here. To do better we could take the std. dev and exclude outliers
// - and potentially do more iterations if there's a high variance.
return sum/(double)iterations;
}
auto getEstimatedClockResolution() -> double {
static auto s_resolution = estimateClockResolution();
return s_resolution;
}
void Timer::start() {
m_nanoseconds = getCurrentNanosecondsSinceEpoch();
}
auto Timer::getElapsedNanoseconds() const -> unsigned int {
return static_cast<unsigned int>(getCurrentNanosecondsSinceEpoch() - m_nanoseconds);
}
auto Timer::getElapsedMicroseconds() const -> unsigned int {
return static_cast<unsigned int>(getElapsedNanoseconds()/1000);
}
auto Timer::getElapsedMilliseconds() const -> unsigned int {
return static_cast<unsigned int>(getElapsedMicroseconds()/1000);
}
auto Timer::getElapsedSeconds() const -> double {
return getElapsedMicroseconds()/1000000.0;
}
} // namespace Catch