C# functions to convert to/from Unix time (seconds since Jan 1, 1970, midnight UTC)

UnixTime.cs

#region Copyright (c) 2016 Atif Aziz. All rights reserved.
//
// 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.
//
#endregion

using System;

// NOTE: .NET Framework 4.6 has built-in functions:
// - DateTimeOffset.FromUnixTimeSeconds
//   https://msdn.microsoft.com/en-us/library/system.datetimeoffset.fromunixtimeseconds.aspx
// - DateTimeOffset.ToUnixTimeSeconds
//   https://msdn.microsoft.com/en-us/library/system.datetimeoffset.tounixtimeseconds.aspx

public static class UnixTime
{
    public static DateTimeOffset Epoch = new DateTimeOffset(new DateTime(1970, 1, 1), TimeSpan.Zero);

    public static double From(DateTimeOffset time) =>
        (time.ToUniversalTime() - Epoch).TotalSeconds;

    public static double From(DateTime time) =>
        (time.ToUniversalTime() - Epoch).TotalSeconds;

    public static DateTimeOffset ToDateTimeOffset(double seconds) =>
        Epoch.AddSeconds(seconds);

    public static DateTimeOffset ToDateTime(double seconds) =>
        ToDateTimeOffset(seconds).LocalDateTime;
}