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387 lines
12 KiB
TypeScript
387 lines
12 KiB
TypeScript
import { snowflakeIdv1Option } from "./snowflakeIdv1Option"
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/**
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*
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*/
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export class snowflakeIdv1 {
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/**
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* 雪花计算方法，（1-漂移算法|2-传统算法），默认 1
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*/
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private Method
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/**
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* 基础时间（ms 单位），不能超过当前系统时间
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*/
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private BaseTime
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/**
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* 机器码，必须由外部设定，最大值 2^WorkerIdBitLength-1
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*/
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private WorkerId
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/**
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* 机器码位长，默认值 6，取值范围 [1, 15](要求：序列数位长+机器码位长不超过 22)
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*/
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private WorkerIdBitLength
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/**
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* 序列数位长，默认值 6，取值范围 [3, 21](要求：序列数位长+机器码位长不超过 22)
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*/
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private SeqBitLength
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/**
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* 最大序列数（含），设置范围 [MinSeqNumber, 2^SeqBitLength-1]，默认值 0，表示最大序列数取最大值（2^SeqBitLength-1]）
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*/
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private MaxSeqNumber
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/**
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* 最小序列数（含），默认值 5，取值范围 [5, MaxSeqNumber]，每毫秒的前 5 个序列数对应编号 0-4 是保留位，其中 1-4 是时间回拨相应预留位，0 是手工新值预留位
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*/
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private MinSeqNumber
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/**
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* 最大漂移次数（含），默认 2000，推荐范围 500-10000（与计算能力有关）
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*/
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private TopOverCostCount
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/**
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*
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*/
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private _TimestampShift
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/**
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*
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*/
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private _CurrentSeqNumber
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/**
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*
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*/
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private _LastTimeTick: bigint
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/**
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* 回拨次序, 支持 4 次回拨次序（避免回拨重叠导致 ID 重复）
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*/
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private _TurnBackTimeTick: bigint
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/**
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*
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*/
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private _TurnBackIndex
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/**
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*
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*/
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private _IsOverCost
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/**
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*
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*/
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private _OverCostCountInOneTerm
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/**
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*Creates an instance of Genid.
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* @author zhupengfeivip
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* @param {{
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* BaseTime: 1577836800000, // 基础时间（ms 单位），默认2020年1月1日，不能超过当前系统时间，一旦投入使用就不能再更改，更改后产生的ID可能会和以前的重复
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* WorkerId: Number, // 机器码，必须由外部设定，最大值 2^WorkerIdBitLength-1
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* WorkerIdBitLength: 6, // 机器码位长，默认值 6，取值范围 [1, 15](要求：序列数位长+机器码位长不超过 22)
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* SeqBitLength: 6, // 序列数位长，默认值 6，取值范围 [3, 21](要求：序列数位长+机器码位长不超过 22)
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* MaxSeqNumber: 5, // 最大序列数（含），设置范围 [MinSeqNumber, 2^SeqBitLength-1]，默认值 0，表示最大序列数取最大值（2^SeqBitLength-1]）
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* MinSeqNumber: 5, // 最小序列数（含），默认值 5，取值范围 [5, MaxSeqNumber]，每毫秒的前 5 个序列数对应编号 0-4 是保留位，其中 1-4 是时间回拨相应预留位，0 是手工新值预留位
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* TopOverCostCount: 2000// 最大漂移次数（含），默认 2000，推荐范围 500-10000（与计算能力有关）
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* }} options
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* @memberof Genid
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*/
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constructor(options: snowflakeIdv1Option) {
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if (options.workerId === undefined)
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throw new Error("lost WorkerId")
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// 1.BaseTime 2020年1月1日 Wed, 01 Jan 2020 00:00:00 GMT 0时区的2020年1月1日
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const BaseTime = 1577836800000
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if (!options.baseTime || options.baseTime < 0)
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options.baseTime = BaseTime
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// 2.WorkerIdBitLength
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const WorkerIdBitLength = 6
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if (!options.workerIdBitLength || options.workerIdBitLength < 0)
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options.workerIdBitLength = WorkerIdBitLength
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// 4.SeqBitLength
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const SeqBitLength = 6
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if (!options.seqBitLength || options.seqBitLength < 0)
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options.seqBitLength = SeqBitLength
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// 5.MaxSeqNumber
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if (options.maxSeqNumber == undefined || options.maxSeqNumber <= 0)
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options.maxSeqNumber = (1 << options.seqBitLength) - 1
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// 6.MinSeqNumber
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const MinSeqNumber = 5
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if (options.minSeqNumber == undefined || options.minSeqNumber < 0)
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options.minSeqNumber = MinSeqNumber
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// 7.Others
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const topOverCostCount = 2000
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if (options.topOverCostCount == undefined || options.topOverCostCount < 0)
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options.topOverCostCount = topOverCostCount
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if (options.method !== 2)
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options.method = 1
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else
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options.method = 2
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this.Method = BigInt(options.method)
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this.BaseTime = BigInt(options.baseTime)
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this.WorkerId = BigInt(options.workerId)
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this.WorkerIdBitLength = BigInt(options.workerIdBitLength)
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this.SeqBitLength = BigInt(options.seqBitLength)
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this.MaxSeqNumber = BigInt(options.maxSeqNumber)
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this.MinSeqNumber = BigInt(options.minSeqNumber)
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this.TopOverCostCount = BigInt(options.topOverCostCount)
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const timestampShift = this.WorkerIdBitLength + this.SeqBitLength
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const currentSeqNumber = this.MinSeqNumber
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this._TimestampShift = timestampShift
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this._CurrentSeqNumber = currentSeqNumber
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this._LastTimeTick = BigInt(0)
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this._TurnBackTimeTick = BigInt(0)
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this._TurnBackIndex = 0
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this._IsOverCost = false
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this._OverCostCountInOneTerm = 0
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}
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/**
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* 当前序列号超过最大范围，开始透支使用序号号的通知事件，，本项暂未实现
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* @returns
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*/
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private BeginOverCostAction(useTimeTick: any) {
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}
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/**
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* 当前序列号超过最大范围，结束透支使用序号号的通知事件，，本项暂未实现
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* @returns
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*/
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private EndOverCostAction(useTimeTick: any) {
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// if m1._TermIndex > 10000 {
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// m1._TermIndex = 0
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// }
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}
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/**
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* 开始时间回拨通知，本项暂未实现
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* @returns
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*/
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private BeginTurnBackAction(useTimeTick: any) {
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}
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/**
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* 结束时间回拨通知，本项暂未实现
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* @returns
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*/
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private EndTurnBackAction(useTimeTick: any) {
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}
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/**
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* 雪花漂移算法
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* @returns
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*/
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private NextOverCostId(): bigint {
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const currentTimeTick = this.GetCurrentTimeTick()
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if (currentTimeTick > this._LastTimeTick) {
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this.EndOverCostAction(currentTimeTick)
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//当前时间大于上次时间，说明是时间是递增的，这是正常情况
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this._LastTimeTick = currentTimeTick
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this._CurrentSeqNumber = this.MinSeqNumber
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this._IsOverCost = false
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this._OverCostCountInOneTerm = 0
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// this._GenCountInOneTerm = 0
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return this.CalcId(this._LastTimeTick)
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}
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if (this._OverCostCountInOneTerm >= this.TopOverCostCount) {
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//当前漂移次数超过最大限制
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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。（该情况发生概率很低）
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this.EndOverCostAction(currentTimeTick)
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this._LastTimeTick = this.GetNextTimeTick()
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this._CurrentSeqNumber = this.MinSeqNumber
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this._IsOverCost = false
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this._OverCostCountInOneTerm = 0
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// this._GenCountInOneTerm = 0
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return this.CalcId(this._LastTimeTick)
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}
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if (this._CurrentSeqNumber > this.MaxSeqNumber) {
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//当前序列数超过最大限制，则要提前透支
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this._LastTimeTick++
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this._CurrentSeqNumber = this.MinSeqNumber
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this._IsOverCost = true
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this._OverCostCountInOneTerm++
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// this._GenCountInOneTerm++
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return this.CalcId(this._LastTimeTick)
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}
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// this._GenCountInOneTerm++
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return this.CalcId(this._LastTimeTick)
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}
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/**
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* 常规雪花算法
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* @returns
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*/
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private NextNormalId() {
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const currentTimeTick = this.GetCurrentTimeTick()
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if (currentTimeTick < this._LastTimeTick) {
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if (this._TurnBackTimeTick < 1) {
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this._TurnBackTimeTick = this._LastTimeTick - BigInt(1)
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this._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 (this._TurnBackIndex > 4)
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this._TurnBackIndex = 1
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this.BeginTurnBackAction(this._TurnBackTimeTick)
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}
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return this.CalcTurnBackId(this._TurnBackTimeTick)
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}
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// 时间追平时，_TurnBackTimeTick 清零
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if (this._TurnBackTimeTick > 0) {
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this.EndTurnBackAction(this._TurnBackTimeTick)
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this._TurnBackTimeTick = BigInt(0)
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}
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if (currentTimeTick > this._LastTimeTick) {
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this._LastTimeTick = currentTimeTick
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this._CurrentSeqNumber = this.MinSeqNumber
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return this.CalcId(this._LastTimeTick)
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}
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if (this._CurrentSeqNumber > this.MaxSeqNumber) {
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this.BeginOverCostAction(currentTimeTick)
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// this._TermIndex++
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this._LastTimeTick++
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this._CurrentSeqNumber = this.MinSeqNumber
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this._IsOverCost = true
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this._OverCostCountInOneTerm = 1
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// this._GenCountInOneTerm = 1
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return this.CalcId(this._LastTimeTick)
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}
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return this.CalcId(this._LastTimeTick)
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}
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/**
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* 生成ID
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* @param useTimeTick 时间戳
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* @returns
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*/
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private CalcId(useTimeTick: bigint) {
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//ID组成 1.相对基础时间的时间差 | 2.WorkerId | 3.序列数
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//时间差，是生成ID时的系统时间减去 BaseTime 的总时间差（毫秒单位）
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const result = BigInt(useTimeTick << this._TimestampShift) + BigInt(this.WorkerId << this.SeqBitLength) + BigInt(this._CurrentSeqNumber)
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this._CurrentSeqNumber++
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return result
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}
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/**
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* 生成时间回拨ID
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* @returns
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*/
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private CalcTurnBackId(useTimeTick: any) {
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const result = BigInt(useTimeTick << this._TimestampShift) + BigInt(this.WorkerId << this.SeqBitLength) + BigInt(this._TurnBackIndex)
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this._TurnBackTimeTick--
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return result
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}
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/**
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*
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* @returns
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*/
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private GetCurrentTimeTick() {
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const millis = BigInt((new Date()).valueOf())
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return millis - this.BaseTime
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}
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/**
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*
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* @returns
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*/
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private GetNextTimeTick() {
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let tempTimeTicker = this.GetCurrentTimeTick()
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while (tempTimeTicker <= this._LastTimeTick) {
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tempTimeTicker = this.GetCurrentTimeTick()
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}
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return tempTimeTicker
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}
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/**
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* 生成ID
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* @returns 始终输出number类型，超过时throw error
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*/
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public NextNumber(): number {
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if (this._IsOverCost) {
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//
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let id = this.NextOverCostId()
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if (id >= 9007199254740992n)
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throw Error(`${id.toString()} over max of Number 9007199254740992`)
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return parseInt(id.toString())
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} else {
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//
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let id = this.NextNormalId()
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if (id >= 9007199254740992n)
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throw Error(`${id.toString()} over max of Number 9007199254740992`)
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return parseInt(id.toString())
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}
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}
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/**
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* 生成ID
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* @returns 根据输出数值判断，小于number最大值时输出number类型，大于时输出bigint
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*/
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public NextId(): number | bigint {
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if (this._IsOverCost) {
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//
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let id = this.NextOverCostId()
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if (id >= 9007199254740992n)
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return id
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else
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return parseInt(id.toString())
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} else {
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//
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let id = this.NextNormalId()
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if (id >= 9007199254740992n)
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return id
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else
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return parseInt(id.toString())
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}
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}
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/**
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* 生成ID
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* @returns 始终输出bigint类型
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*/
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public NextBigId(): bigint {
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if (this._IsOverCost) {
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//
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return this.NextOverCostId()
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} else {
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//
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return this.NextNormalId()
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}
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}
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}
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