76 lines
2.1 KiB
C#
76 lines
2.1 KiB
C#
// Copyright 2022 Robotec.ai.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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using System;
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using System.Diagnostics;
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namespace ROS2
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{
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/// <summary>
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/// DateTime based clock that has resolution increased using Stopwatch.
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/// DateTime is used to synchronize since Stopwatch tends to drift.
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/// </summary>
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public class DotnetTimeSource : ITimeSource
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{
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private readonly double maxUnsyncedSeconds = 10;
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private Stopwatch stopwatch = new Stopwatch();
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private readonly object mutex = new object();
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private double systemTimeIntervalStart = 0;
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private double stopwatchStartTimeStamp;
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private double TotalSystemTimeSeconds()
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{
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return TimeSpan.FromTicks(DateTime.UtcNow.Ticks).TotalSeconds;
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}
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private void UpdateSystemTime()
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{
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systemTimeIntervalStart = TotalSystemTimeSeconds();
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stopwatchStartTimeStamp = Stopwatch.GetTimestamp();
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}
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public DotnetTimeSource()
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{
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UpdateSystemTime();
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}
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public void GetTime(out int seconds, out uint nanoseconds)
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{
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lock(mutex) // Threading
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{
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double endTimestamp = Stopwatch.GetTimestamp();
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var durationInSeconds = endTimestamp - stopwatchStartTimeStamp;
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double timeOffset = 0;
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if (durationInSeconds >= maxUnsyncedSeconds)
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{ // acquire DateTime to sync
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UpdateSystemTime();
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}
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else
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{ // use Stopwatch offset
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timeOffset = durationInSeconds;
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}
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TimeUtils.TimeFromTotalSeconds(systemTimeIntervalStart + timeOffset, out seconds, out nanoseconds);
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}
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}
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}
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} // namespace ROS2
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