round.hpp

Go to the documentation of this file.

// SPDX-License-Identifier: BSL-1.0
// SPDX-FileCopyrightText: Copyright (C) 2019 Tobias Hienzsch
 
#ifndef TETL_CHRONO_ROUND_HPP
#define TETL_CHRONO_ROUND_HPP
 
#include <etl/_chrono/duration_cast.hpp>
#include <etl/_chrono/time_point_cast.hpp>
#include <etl/_type_traits/is_arithmetic.hpp>
 
namespace etl::chrono {
 
/// \ingroup chrono
template <typename To, typename Rep, typename Period>
    requires(detail::is_duration_v<To>)
[[nodiscard]] constexpr auto
round(duration<Rep, Period> const& dur) noexcept(is_arithmetic_v<Rep> and is_arithmetic_v<typename To::rep>) -> To
{
    auto const low      = floor<To>(dur);
    auto const high     = low + To{1};
    auto const lowDiff  = dur - low;
    auto const highDiff = high - dur;
    if (lowDiff < highDiff) {
        return low;
    }
    if (lowDiff > highDiff) {
        return high;
    }
    return low.count() & 1 ? high : low;
}
 
/// \ingroup chrono
template <typename To, typename Clock, typename Duration>
    requires(detail::is_duration_v<To>)
[[nodiscard]] constexpr auto round(time_point<Clock, Duration> const& tp) -> time_point<Clock, To>
{
    return time_point<Clock, To>{round<To>(tp.time_since_epoch())};
}
 
} // namespace etl::chrono
 
#endif // TETL_CHRONO_ROUND_HPP