记录雪花算法Snowflake

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using System; using System.Diagnostics; using System.Threading; using NewLife.Common;   namespace NewLife.Data {     /// <summary>流式Id</summary>     [Obsolete("=>SnowFlake")]     public class FlowId : Snowflake { }       /// <summary>雪花算法。分布式Id</summary>     /// <remarks>     /// 文档 https://www.yuque.com/smartstone/nx/snow_flake     ///     /// 使用一个 64 bit 的 long 型的数字作为全局唯一 id。在分布式系统中的应用十分广泛，且ID 引入了时间戳，基本上保持自增。     /// 1bit保留 + 41bit时间戳 + 10bit机器 + 12bit序列号     /// </remarks>     public class Snowflake     {         #region 属性         /// <summary>开始时间戳。首次使用前设置，否则无效，默认1970-1-1</summary>         public DateTime StartTimestamp { get; set; } = new DateTime(1970, 1, 1);           /// <summary>机器Id，取10位</summary>         public Int32 WorkerId { get; set; }           private Int32 _Sequence;         /// <summary>序列号，取12位</summary>         public Int32 Sequence { get => _Sequence; set => _Sequence = value; }           private Int64 _msStart;         private Stopwatch _watch;         private Int64 _lastTime;         #endregion           #region 核心方法         private void Init()         {             // 初始化WorkerId，取5位实例加上5位进程，确保同一台机器的WorkerId不同             if (WorkerId <= 0)             {                 var nodeId = SysConfig.Current.Instance;                 var pid = Process.GetCurrentProcess().Id;                 var tid = Thread.CurrentThread.ManagedThreadId;                 //WorkerId = ((nodeId & 0x1F) << 5) | (pid & 0x1F);                 //WorkerId = (nodeId ^ pid ^ tid) & 0x3FF;                 WorkerId = ((nodeId & 0x1F) << 5) | ((pid ^ tid) & 0x1F);             }               // 记录此时距离起点的毫秒数以及开机嘀嗒数             if (_watch == null)             {                 _msStart = (Int64)(DateTime.Now - StartTimestamp).TotalMilliseconds;                 _watch = Stopwatch.StartNew();             }         }           /// <summary>获取下一个Id</summary>         /// <returns></returns>         public virtual Int64 NewId()         {             Init();               // 此时嘀嗒数减去起点嘀嗒数，加上七点毫秒数             //var ms = (Int64)(DateTime.Now - StartTimestamp).TotalMilliseconds;             var ms = _watch.ElapsedMilliseconds + _msStart;             var wid = WorkerId & 0x3FF;             var seq = Interlocked.Increment(ref _Sequence) & 0x0FFF;               //!!! 避免时间倒退             if (ms < _lastTime) ms = _lastTime;               // 相同毫秒内，如果序列号用尽，则可能超过4096，导致生成重复Id             // 睡眠1毫秒，抢占它的位置 @656092719（广西-风吹面）             if (_lastTime == ms && seq == 0)             {                 //ms++;                 // spin等1000次耗时141us，10000次耗时397us，100000次耗时3231us。@i9-10900k                 //Thread.SpinWait(1000);                 while (_lastTime == ms) ms = _watch.ElapsedMilliseconds + _msStart;             }             _lastTime = ms;               /*              * 每个毫秒内_Sequence没有归零，主要是为了安全，避免被人猜测得到前后Id。              * 而毫秒内的顺序，重要性不大。              */               return (ms << (10 + 12)) | (Int64)(wid << 12) | (Int64)seq;         }           /// <summary>获取指定时间的Id，带上节点和序列号。可用于根据业务时间构造插入Id</summary>         /// <param name="time">时间</param>         /// <returns></returns>         public virtual Int64 NewId(DateTime time)         {             Init();               var ms = (Int64)(time - StartTimestamp).TotalMilliseconds;             var wid = WorkerId & 0x3FF;             var seq = Interlocked.Increment(ref _Sequence) & 0x0FFF;               return (ms << (10 + 12)) | (Int64)(wid << 12) | (Int64)seq;         }           /// <summary>时间转为Id，不带节点和序列号。可用于构建时间片段查询</summary>         /// <param name="time">时间</param>         /// <returns></returns>         public virtual Int64 GetId(DateTime time)         {             var t = (Int64)(time - StartTimestamp).TotalMilliseconds;             return t << (10 + 12);         }           /// <summary>尝试分析</summary>         /// <param name="id"></param>         /// <param name="time">时间</param>         /// <param name="workerId">节点</param>         /// <param name="sequence">序列号</param>         /// <returns></returns>         public virtual Boolean TryParse(Int64 id, out DateTime time, out Int32 workerId, out Int32 sequence)         {             time = StartTimestamp.AddMilliseconds(id >> (10 + 12));             workerId = (Int32)((id >> 12) & 0x3FF);             sequence = (Int32)(id & 0x0FFF);               return true;         }         #endregion     } }

代码地址：https://github.com/NewLifeX/X/blob/master/NewLife.Core/Data/Snowflake.cs