380 lines
10 KiB
C#
380 lines
10 KiB
C#
/*
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* 版权属于：yitter(yitter@126.com)
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* 开源地址：https://github.com/yitter/idgenerator
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* 版权协议：MIT
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* 版权说明：只要保留本版权，你可以免费使用、修改、分发本代码。
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* 免责条款：任何因为本代码产生的系统、法律、政治、宗教问题，均与版权所有者无关。
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*
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*/
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using System;
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using System.Threading;
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using System.Threading.Tasks;
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namespace Yitter.IdGenerator
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{
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/// <summary>
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/// 雪花漂移算法
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/// </summary>
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internal class SnowWorkerM1 : ISnowWorker
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{
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/// <summary>
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/// 基础时间
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/// </summary>
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protected readonly DateTime BaseTime;
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/// <summary>
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/// 机器码
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/// </summary>
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protected readonly ushort WorkerId = 0;
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/// <summary>
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/// 机器码位长
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/// </summary>
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protected readonly byte WorkerIdBitLength = 0;
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/// <summary>
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/// 自增序列数位长
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/// </summary>
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protected readonly byte SeqBitLength = 0;
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/// <summary>
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/// 最大序列数（含）
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/// </summary>
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protected readonly int MaxSeqNumber = 0;
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/// <summary>
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/// 最小序列数（含）
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/// </summary>
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protected readonly ushort MinSeqNumber = 0;
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/// <summary>
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/// 最大漂移次数（含）
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/// </summary>
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protected int TopOverCostCount = 0;
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protected byte _TimestampShift = 0;
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protected static object _SyncLock = new object();
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protected ushort _CurrentSeqNumber = 0;
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protected long _LastTimeTick = 0; // -1L
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protected long _TurnBackTimeTick = 0; // -1L;
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protected byte _TurnBackIndex = 0;
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protected bool _IsOverCost = false;
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protected int _OverCostCountInOneTerm = 0;
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#if DEBUG
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protected int _GenCountInOneTerm = 0;
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protected int _TermIndex = 0;
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#endif
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public Action<OverCostActionArg> GenAction { get; set; }
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//private static long _StartTimeTick = 0;
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//private static long _BaseTimeTick = 0;
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public SnowWorkerM1(IdGeneratorOptions options)
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{
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// 1.BaseTime
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if (options.BaseTime != DateTime.MinValue)
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{
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BaseTime = options.BaseTime;
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}
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// 2.WorkerIdBitLength
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if (options.WorkerIdBitLength == 0)
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{
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WorkerIdBitLength = 6;
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}
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else
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{
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WorkerIdBitLength = options.WorkerIdBitLength;
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}
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// 3.WorkerId
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WorkerId = options.WorkerId;
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// 4.SeqBitLength
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if (options.SeqBitLength == 0)
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{
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SeqBitLength = 6;
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}
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else
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{
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SeqBitLength = options.SeqBitLength;
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}
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// 5.MaxSeqNumber
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if (options.MaxSeqNumber <= 0)
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{
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MaxSeqNumber = (1 << SeqBitLength) - 1;
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}
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else
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{
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MaxSeqNumber = options.MaxSeqNumber;
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}
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// 6.MinSeqNumber
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MinSeqNumber = options.MinSeqNumber;
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// 7.Others
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TopOverCostCount = options.TopOverCostCount;
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//if (TopOverCostCount == 0)
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//{
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// TopOverCostCount = 2000;
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//}
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_TimestampShift = (byte)(WorkerIdBitLength + SeqBitLength);
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_CurrentSeqNumber = options.MinSeqNumber;
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//_BaseTimeTick = BaseTime.Ticks;
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//_StartTimeTick = (long)(DateTime.UtcNow.Subtract(BaseTime).TotalMilliseconds) - Environment.TickCount;
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}
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#if DEBUG
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private void DoGenIdAction(OverCostActionArg arg)
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{
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//return;
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Task.Run(() =>
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{
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GenAction(arg);
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});
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}
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private void BeginOverCostAction(in long useTimeTick)
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{
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if (GenAction == null)
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{
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return;
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}
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DoGenIdAction(new OverCostActionArg(
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WorkerId,
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useTimeTick,
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1,
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_OverCostCountInOneTerm,
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_GenCountInOneTerm,
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_TermIndex));
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}
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private void EndOverCostAction(in long useTimeTick)
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{
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//if (_TermIndex > 10000)
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//{
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// _TermIndex = 0;
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//}
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if (GenAction == null)
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{
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return;
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}
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DoGenIdAction(new OverCostActionArg(
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WorkerId,
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useTimeTick,
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2,
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_OverCostCountInOneTerm,
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_GenCountInOneTerm,
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_TermIndex));
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}
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private void BeginTurnBackAction(in long useTimeTick)
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{
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if (GenAction == null)
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{
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return;
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}
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DoGenIdAction(new OverCostActionArg(
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WorkerId,
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useTimeTick,
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8,
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0,
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0,
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_TurnBackIndex));
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}
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private void EndTurnBackAction(in long useTimeTick)
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{
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if (GenAction == null)
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{
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return;
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}
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DoGenIdAction(new OverCostActionArg(
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WorkerId,
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useTimeTick,
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9,
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0,
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0,
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_TurnBackIndex));
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}
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#endif
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protected virtual long NextOverCostId()
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{
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long currentTimeTick = GetCurrentTimeTick();
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if (currentTimeTick > _LastTimeTick)
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{
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#if DEBUG
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EndOverCostAction(currentTimeTick);
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_GenCountInOneTerm = 0;
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#endif
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_LastTimeTick = currentTimeTick;
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_CurrentSeqNumber = MinSeqNumber;
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_IsOverCost = false;
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_OverCostCountInOneTerm = 0;
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return CalcId(_LastTimeTick);
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}
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if (_OverCostCountInOneTerm >= TopOverCostCount)
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{
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#if DEBUG
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EndOverCostAction(currentTimeTick);
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_GenCountInOneTerm = 0;
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#endif
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// TODO: 在漂移终止，等待时间对齐时，如果发生时间回拨较长，则此处可能等待较长时间。可优化为：在漂移终止时增加时间回拨应对逻辑。（该情况发生概率低，暂不处理）
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_LastTimeTick = GetNextTimeTick();
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_CurrentSeqNumber = MinSeqNumber;
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_IsOverCost = false;
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_OverCostCountInOneTerm = 0;
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return CalcId(_LastTimeTick);
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}
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if (_CurrentSeqNumber > MaxSeqNumber)
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{
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#if DEBUG
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_GenCountInOneTerm++;
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#endif
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_LastTimeTick++;
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_CurrentSeqNumber = MinSeqNumber;
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_IsOverCost = true;
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_OverCostCountInOneTerm++;
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return CalcId(_LastTimeTick);
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}
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#if DEBUG
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_GenCountInOneTerm++;
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#endif
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return CalcId(_LastTimeTick);
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}
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protected virtual long NextNormalId()
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{
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long currentTimeTick = GetCurrentTimeTick();
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if (currentTimeTick < _LastTimeTick)
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{
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if (_TurnBackTimeTick < 1)
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{
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_TurnBackTimeTick = _LastTimeTick - 1;
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_TurnBackIndex++;
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// 每毫秒序列数的前5位是预留位，0用于手工新值，1-4是时间回拨次序
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// 支持4次回拨次序（避免回拨重叠导致ID重复），可无限次回拨（次序循环使用）。
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if (_TurnBackIndex > 4)
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{
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_TurnBackIndex = 1;
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}
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#if DEBUG
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BeginTurnBackAction(_TurnBackTimeTick);
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#endif
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}
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//Thread.Sleep(1);
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return CalcTurnBackId(_TurnBackTimeTick);
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}
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// 时间追平时，_TurnBackTimeTick清零
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if (_TurnBackTimeTick > 0)
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{
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#if DEBUG
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EndTurnBackAction(_TurnBackTimeTick);
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#endif
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_TurnBackTimeTick = 0;
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}
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if (currentTimeTick > _LastTimeTick)
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{
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_LastTimeTick = currentTimeTick;
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_CurrentSeqNumber = MinSeqNumber;
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return CalcId(_LastTimeTick);
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}
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if (_CurrentSeqNumber > MaxSeqNumber)
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{
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#if DEBUG
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BeginOverCostAction(currentTimeTick);
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_TermIndex++;
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_GenCountInOneTerm = 1;
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#endif
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_OverCostCountInOneTerm = 1;
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_LastTimeTick++;
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_CurrentSeqNumber = MinSeqNumber;
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_IsOverCost = true;
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return CalcId(_LastTimeTick);
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}
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return CalcId(_LastTimeTick);
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}
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protected virtual long CalcId(long useTimeTick)
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{
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var result = ((useTimeTick << _TimestampShift) +
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((long)WorkerId << SeqBitLength) +
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(uint)_CurrentSeqNumber);
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_CurrentSeqNumber++;
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return result;
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}
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protected virtual long CalcTurnBackId(long useTimeTick)
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{
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var result = ((useTimeTick << _TimestampShift) +
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((long)WorkerId << SeqBitLength) + _TurnBackIndex);
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_TurnBackTimeTick--;
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return result;
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}
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protected virtual long GetCurrentTimeTick()
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{
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//return (long)(DateTime.UtcNow - BaseTime).Ticks;
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//return (long)(_StartTimeTick + Environment.TickCount);
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return (long)(DateTime.UtcNow - BaseTime).TotalMilliseconds;
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}
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protected virtual long GetNextTimeTick()
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{
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long tempTimeTicker = GetCurrentTimeTick();
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while (tempTimeTicker <= _LastTimeTick)
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{
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//Thread.Sleep(1);
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SpinWait.SpinUntil(() => false, 1);
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tempTimeTicker = GetCurrentTimeTick();
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}
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return tempTimeTicker;
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}
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public virtual long NextId()
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{
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lock (_SyncLock)
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{
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return _IsOverCost ? NextOverCostId() : NextNormalId();
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}
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}
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}
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}
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