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time.h
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time.h
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/*
* Copyright 2016 The Cartographer Authors
*
* 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.
*/
#ifndef CARTOGRAPHER_COMMON_TIME_H_
#define CARTOGRAPHER_COMMON_TIME_H_
#include <chrono>
#include <ostream>
#include <ratio>
#include "cartographer/common/port.h"
namespace cartographer {
namespace common {
constexpr int64 kUtsEpochOffsetFromUnixEpochInSeconds =
(719162ll * 24ll * 60ll * 60ll);
struct UniversalTimeScaleClock {
using rep = int64;
using period = std::ratio<1, 10000000>;
using duration = std::chrono::duration<rep, period>;
using time_point = std::chrono::time_point<UniversalTimeScaleClock>;
static constexpr bool is_steady = true;
};
// Represents Universal Time Scale durations and timestamps which are 64-bit
// integers representing the 100 nanosecond ticks since the Epoch which is
// January 1, 1 at the start of day in UTC.
using Duration = UniversalTimeScaleClock::duration;
using Time = UniversalTimeScaleClock::time_point;
// Convenience functions to create common::Durations.
Duration FromSeconds(double seconds);
Duration FromMilliseconds(int64 milliseconds);
// Returns the given duration in seconds.
double ToSeconds(Duration duration);
// Creates a time from a Universal Time Scale.
Time FromUniversal(int64 ticks);
// Outputs the Universal Time Scale timestamp for a given Time.
int64 ToUniversal(Time time);
// For logging and unit tests, outputs the timestamp integer.
std::ostream& operator<<(std::ostream& os, Time time);
} // namespace common
} // namespace cartographer
#endif // CARTOGRAPHER_COMMON_TIME_H_