UnixTime.cs

using System;
using System.Collections.Generic;
using System.Text;

namespace UnifiProtect_ClipSaver
{
    public static class UnixTime
    {
        private static readonly DateTime UnixEpoch =
            new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);

        public static long GetUnixTime(this DateTime datetime)
        {
            return (long)datetime.Subtract(UnixEpoch).TotalSeconds;
        }

        public static long GetUnixTimeMillis(this DateTime datetime)
        {
            return (long)datetime.Subtract(UnixEpoch).TotalMilliseconds;
        }

        public static long GetCurrentUnixTimestampMillis()
        {
            return (long)(DateTime.UtcNow - UnixEpoch).TotalMilliseconds;
        }

        public static DateTime DateTimeFromUnixTimestampMillis(long millis)
        {
            return UnixEpoch.AddMilliseconds(millis);
        }

        public static long GetCurrentUnixTimestampSeconds()
        {
            return (long)(DateTime.UtcNow - UnixEpoch).TotalSeconds;
        }

        public static DateTime DateTimeFromUnixTimestampSeconds(long seconds)
        {
            return UnixEpoch.AddSeconds(seconds);
        }
    }
}