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- /*
- * Copyright 2017-present Facebook, Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
- #pragma once
- #include <chrono>
- #include <stdexcept>
- #include <type_traits>
- #include <folly/Portability.h>
- #include <folly/lang/Exception.h>
- #include <folly/portability/Time.h>
- /***
- * include or backport:
- * * std::chrono::ceil
- * * std::chrono::floor
- * * std::chrono::round
- */
- #if __cpp_lib_chrono >= 201510 || _MSC_VER
- namespace folly {
- namespace chrono {
- /* using override */ using std::chrono::ceil;
- /* using override */ using std::chrono::floor;
- /* using override */ using std::chrono::round;
- } // namespace chrono
- } // namespace folly
- #else
- namespace folly {
- namespace chrono {
- namespace detail {
- // from: http://en.cppreference.com/w/cpp/chrono/duration/ceil, CC-BY-SA
- template <typename T>
- struct is_duration : std::false_type {};
- template <typename Rep, typename Period>
- struct is_duration<std::chrono::duration<Rep, Period>> : std::true_type {};
- template <typename To, typename Duration>
- constexpr To ceil_impl(Duration const& d, To const& t) {
- return t < d ? t + To{1} : t;
- }
- template <typename To, typename Duration>
- constexpr To floor_impl(Duration const& d, To const& t) {
- return t > d ? t - To{1} : t;
- }
- template <typename To, typename Diff>
- constexpr To round_impl(To const& t0, To const& t1, Diff diff0, Diff diff1) {
- return diff0 < diff1 ? t0 : diff1 < diff0 ? t1 : t0.count() & 1 ? t1 : t0;
- }
- template <typename To, typename Duration>
- constexpr To round_impl(Duration const& d, To const& t0, To const& t1) {
- return round_impl(t0, t1, d - t0, t1 - d);
- }
- template <typename To, typename Duration>
- constexpr To round_impl(Duration const& d, To const& t0) {
- return round_impl(d, t0, t0 + To{1});
- }
- } // namespace detail
- // mimic: std::chrono::ceil, C++17
- // from: http://en.cppreference.com/w/cpp/chrono/duration/ceil, CC-BY-SA
- template <
- typename To,
- typename Rep,
- typename Period,
- typename = typename std::enable_if<detail::is_duration<To>::value>::type>
- constexpr To ceil(std::chrono::duration<Rep, Period> const& d) {
- return detail::ceil_impl(d, std::chrono::duration_cast<To>(d));
- }
- // mimic: std::chrono::ceil, C++17
- // from: http://en.cppreference.com/w/cpp/chrono/time_point/ceil, CC-BY-SA
- template <
- typename To,
- typename Clock,
- typename Duration,
- typename = typename std::enable_if<detail::is_duration<To>::value>::type>
- constexpr std::chrono::time_point<Clock, To> ceil(
- std::chrono::time_point<Clock, Duration> const& tp) {
- return std::chrono::time_point<Clock, To>{ceil<To>(tp.time_since_epoch())};
- }
- // mimic: std::chrono::floor, C++17
- // from: http://en.cppreference.com/w/cpp/chrono/duration/floor, CC-BY-SA
- template <
- typename To,
- typename Rep,
- typename Period,
- typename = typename std::enable_if<detail::is_duration<To>::value>::type>
- constexpr To floor(std::chrono::duration<Rep, Period> const& d) {
- return detail::floor_impl(d, std::chrono::duration_cast<To>(d));
- }
- // mimic: std::chrono::floor, C++17
- // from: http://en.cppreference.com/w/cpp/chrono/time_point/floor, CC-BY-SA
- template <
- typename To,
- typename Clock,
- typename Duration,
- typename = typename std::enable_if<detail::is_duration<To>::value>::type>
- constexpr std::chrono::time_point<Clock, To> floor(
- std::chrono::time_point<Clock, Duration> const& tp) {
- return std::chrono::time_point<Clock, To>{floor<To>(tp.time_since_epoch())};
- }
- // mimic: std::chrono::round, C++17
- // from: http://en.cppreference.com/w/cpp/chrono/duration/round, CC-BY-SA
- template <
- typename To,
- typename Rep,
- typename Period,
- typename = typename std::enable_if<
- detail::is_duration<To>::value &&
- !std::chrono::treat_as_floating_point<typename To::rep>::value>::type>
- constexpr To round(std::chrono::duration<Rep, Period> const& d) {
- return detail::round_impl(d, floor<To>(d));
- }
- // mimic: std::chrono::round, C++17
- // from: http://en.cppreference.com/w/cpp/chrono/time_point/round, CC-BY-SA
- template <
- typename To,
- typename Clock,
- typename Duration,
- typename = typename std::enable_if<
- detail::is_duration<To>::value &&
- !std::chrono::treat_as_floating_point<typename To::rep>::value>::type>
- constexpr std::chrono::time_point<Clock, To> round(
- std::chrono::time_point<Clock, Duration> const& tp) {
- return std::chrono::time_point<Clock, To>{round<To>(tp.time_since_epoch())};
- }
- } // namespace chrono
- } // namespace folly
- #endif
- namespace folly {
- namespace chrono {
- struct coarse_steady_clock {
- using rep = std::chrono::milliseconds::rep;
- using period = std::chrono::milliseconds::period;
- using duration = std::chrono::duration<rep, period>;
- using time_point = std::chrono::time_point<coarse_steady_clock, duration>;
- constexpr static bool is_steady = true;
- static time_point now() {
- #ifndef CLOCK_MONOTONIC_COARSE
- return time_point(std::chrono::duration_cast<duration>(
- std::chrono::steady_clock::now().time_since_epoch()));
- #else
- timespec ts;
- auto ret = clock_gettime(CLOCK_MONOTONIC_COARSE, &ts);
- if (ret != 0) {
- throw_exception<std::runtime_error>(
- "Error using CLOCK_MONOTONIC_COARSE.");
- }
- return time_point(std::chrono::duration_cast<duration>(
- std::chrono::seconds(ts.tv_sec) +
- std::chrono::nanoseconds(ts.tv_nsec)));
- #endif
- }
- };
- } // namespace chrono
- } // namespace folly
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