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https://gitee.com/yitter/idgenerator.git
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405 lines
10 KiB
ObjectPascal
405 lines
10 KiB
ObjectPascal
unit uSnowWorkerM1;
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interface
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uses
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uISnowWorker, uIdGeneratorOptions, System.SyncObjs, uTOverCostActionArg, System.DateUtils, System.SysUtils;
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/// <summary>
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/// 雪花漂移算法
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/// </summary>
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type
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TSnowWorkerM1 = class(TInterfacedObject, ISnowWorker)
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private
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// private static long _StartTimeTick = 0;
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// private static long _BaseTimeTick = 0;
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protected
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SyncLock: TCriticalSection;
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protected
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// FBaseTime: TDateTime;
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FBaseTime: Int64;
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FWorkerId: Word;
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FWorkerIdBitLength: Byte;
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FSeqBitLength: Byte;
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FMaxSeqNumber: Integer;
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FMinSeqNumber: Word;
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FTopOverCostCount: Integer;
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//
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FTimestampShift: Byte;
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FCurrentSeqNumber: Word;
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FLastTimeTick: Int64;
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FTurnBackTimeTick: Int64;
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FTurnBackIndex: Byte;
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FIsOverCost: Boolean;
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FOverCostCountInOneTerm: Integer;
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//
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FGenCountInOneTerm: Integer;
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FTermIndex: Integer;
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protected
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/// <summary>
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/// 基础时间
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/// </summary>
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// property BaseTime: TDateTime read FBaseTime write FBaseTime;
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property BaseTime: Int64 read FBaseTime;
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/// <summary>
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/// 机器码
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/// </summary>
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property WorkerId: Word read FWorkerId default 0;
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/// <summary>
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/// 机器码位长
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/// </summary>
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property WorkerIdBitLength: Byte read FWorkerIdBitLength default 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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property SeqBitLength: Byte read FSeqBitLength default 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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property MaxSeqNumber: Integer read FMaxSeqNumber default 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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property MinSeqNumber: Word read FMinSeqNumber default 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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property TopOverCostCount: Integer read FTopOverCostCount write FTopOverCostCount default 0;
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//
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property TimestampShift: Byte read FTimestampShift write FTimestampShift default 0;
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//
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property CurrentSeqNumber: Word read FCurrentSeqNumber write FCurrentSeqNumber;
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property LastTimeTick: Int64 read FLastTimeTick write FLastTimeTick default 0; // -1L
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property TurnBackTimeTick: Int64 read FTurnBackTimeTick write FTurnBackTimeTick default 0; // -1L;
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property TurnBackIndex: Byte read FTurnBackIndex write FTurnBackIndex default 0;
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property IsOverCost: Boolean read FIsOverCost write FIsOverCost default False;
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property OverCostCountInOneTerm: Integer read FOverCostCountInOneTerm write FOverCostCountInOneTerm default 0;
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{$IFDEF DEBUG}
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property GenCountInOneTerm: Integer read FGenCountInOneTerm write FGenCountInOneTerm default 0;
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property TermIndex: Integer read FTermIndex write FTermIndex default 0;
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{$ENDIF}
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protected
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{$IFDEF DEBUG}
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procedure DoGenIdAction(arg: TOverCostActionArg);
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procedure BeginOverCostAction(UseTimeTick: Int64);
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procedure EndOverCostAction(UseTimeTick: Int64);
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procedure BeginTurnBackAction(UseTimeTick: Int64);
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procedure EndTurnBackAction(UseTimeTick: Int64);
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{$ENDIF}
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//
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function GetSecondTimeStamp(): Int64;
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function GetMillisecondTimeStamp(): Int64;
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//
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function CalcId(UseTimeTick: Int64): Int64; virtual;
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function CalcTurnBackId(UseTimeTick: Int64): Int64; virtual;
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function NextOverCostId(): Int64;
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function GetCurrentTimeTick(): Int64; virtual;
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function GetNextTimeTick(): Int64;
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public
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// Action<OverCostActionArg> GenAction { get; set; }
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function NextId(): Int64;
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function NextNormalId(): Int64;
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constructor Create(options: TIdGeneratorOptions); overload;
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destructor Destroy(); override;
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end;
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implementation
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{ TSnowWorkerM1 }
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function TSnowWorkerM1.GetSecondTimeStamp(): Int64;
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var
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ST: TDateTime;
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begin
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ST := EncodeDateTime(1970, 1, 1, 0, 0, 0, 0);
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Result := MilliSecondsBetween(Now(), ST) - 28800; // 8*60*60;
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end;
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function TSnowWorkerM1.GetMillisecondTimeStamp(): Int64;
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var
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ST: TDateTime;
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begin
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ST := EncodeDateTime(1970, 1, 1, 0, 0, 0, 0);
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Result := MilliSecondsBetween(Now(), ST) - 28800000; // 8*60*60*1000;
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end;
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constructor TSnowWorkerM1.Create(options: TIdGeneratorOptions);
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begin
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SyncLock := TCriticalSection.Create;
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// 1.BaseTime
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if (options.BaseTime <> 0) then
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FBaseTime := options.BaseTime;
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// 2.WorkerIdBitLength
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if (options.WorkerIdBitLength <> 0) then
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begin
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FWorkerIdBitLength := 6;
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end
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else
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begin
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FWorkerIdBitLength := options.WorkerIdBitLength;
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end;
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// 3.WorkerId
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FWorkerId := options.WorkerId;
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// 4.SeqBitLength
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if (options.SeqBitLength = 0) then
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begin
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FSeqBitLength := 6;
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end
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else
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begin
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FSeqBitLength := options.SeqBitLength;
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end;
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// 5.MaxSeqNumber
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if (options.MaxSeqNumber <= 0) then
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begin
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FMaxSeqNumber := (1 shl SeqBitLength) - 1;
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end
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else
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begin
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FMaxSeqNumber := options.MaxSeqNumber;
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end;
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// 6.MinSeqNumber
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FMinSeqNumber := options.MinSeqNumber;
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// 7.Others
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FTopOverCostCount := options.TopOverCostCount;
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// if (TopOverCostCount = 0) then
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// begin
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// FTopOverCostCount := 2000;
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// end;
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FTimestampShift := Byte(WorkerIdBitLength + SeqBitLength);
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FCurrentSeqNumber := options.MinSeqNumber;
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// FBaseTimeTick = BaseTime.Ticks;
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// FStartTimeTick = (long)(DateTime.UtcNow.Subtract(BaseTime).TotalMilliseconds) - Environment.TickCount;
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end;
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destructor TSnowWorkerM1.Destroy();
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begin
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SyncLock.Free;
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inherited;
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end;
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{$IFDEF DEBUG}
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procedure TSnowWorkerM1.DoGenIdAction(arg: TOverCostActionArg);
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begin
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// //return;
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// Task.Run(() =>
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// {
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// GenAction(arg);
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// });
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end;
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procedure TSnowWorkerM1.BeginOverCostAction(UseTimeTick: Int64);
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begin
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end;
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procedure TSnowWorkerM1.EndOverCostAction(UseTimeTick: Int64);
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begin
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end;
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procedure TSnowWorkerM1.BeginTurnBackAction(UseTimeTick: Int64);
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begin
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end;
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procedure TSnowWorkerM1.EndTurnBackAction(UseTimeTick: Int64);
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begin
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end;
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{$ENDIF}
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function TSnowWorkerM1.NextOverCostId(): Int64;
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var
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CurrentTimeTick: Int64;
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begin
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CurrentTimeTick := GetCurrentTimeTick();
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if (CurrentTimeTick > FLastTimeTick) then
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begin
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{$IFDEF DEBUG}
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EndOverCostAction(CurrentTimeTick);
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FGenCountInOneTerm := 0;
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{$ENDIF}
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FLastTimeTick := CurrentTimeTick;
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FCurrentSeqNumber := FMinSeqNumber;
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FIsOverCost := False;
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FOverCostCountInOneTerm := 0;
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Result := CalcId(FLastTimeTick);
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Exit;
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end;
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if (FOverCostCountInOneTerm >= FTopOverCostCount) then
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begin
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{$IFDEF DEBUG}
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EndOverCostAction(CurrentTimeTick);
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FGenCountInOneTerm := 0;
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{$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。
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// 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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FLastTimeTick := GetNextTimeTick();
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FCurrentSeqNumber := FMinSeqNumber;
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FIsOverCost := False;
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FOverCostCountInOneTerm := 0;
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Result := CalcId(FLastTimeTick);
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Exit;
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end;
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if (FCurrentSeqNumber > FMaxSeqNumber) then
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begin
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{$IFDEF DEBUG}
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Inc(FGenCountInOneTerm);
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{$ENDIF}
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Inc(FLastTimeTick);
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FCurrentSeqNumber := FMinSeqNumber;
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FIsOverCost := True;
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Inc(FOverCostCountInOneTerm);
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Result := CalcId(FLastTimeTick);
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Exit;
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end;
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{$IFDEF DEBUG}
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Inc(FGenCountInOneTerm);
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{$ENDIF}
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Result := CalcId(FLastTimeTick);
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end;
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function TSnowWorkerM1.NextNormalId: Int64;
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var
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CurrentTimeTick: Int64;
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begin
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CurrentTimeTick := GetCurrentTimeTick();
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if (CurrentTimeTick < FLastTimeTick) then
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begin
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if (FTurnBackTimeTick < 1) then
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begin
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FTurnBackTimeTick := FLastTimeTick - 1;
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Inc(FTurnBackIndex);
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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 (FTurnBackIndex > 4) then
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begin
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FTurnBackIndex := 1;
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end;
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{$IFDEF DEBUG}
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BeginTurnBackAction(FTurnBackTimeTick);
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{$ENDIF}
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end;
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// Sleep(1);
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Result := CalcTurnBackId(FTurnBackTimeTick);
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Exit;
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end;
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// 时间追平时，_TurnBackTimeTick清零
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if (FTurnBackTimeTick > 0) then
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begin
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{$IFDEF DEBUG}
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EndTurnBackAction(FTurnBackTimeTick);
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{$ENDIF}
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FTurnBackTimeTick := 0;
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end;
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if (CurrentTimeTick > FLastTimeTick) then
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begin
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FLastTimeTick := CurrentTimeTick;
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FCurrentSeqNumber := FMinSeqNumber;
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Result := CalcId(FLastTimeTick);
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Exit;
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end;
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if (FCurrentSeqNumber > FMaxSeqNumber) then
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begin
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{$IFDEF DEBUG}
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BeginOverCostAction(CurrentTimeTick);
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Inc(FTermIndex);
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FGenCountInOneTerm := 1;
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{$ENDIF}
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FOverCostCountInOneTerm := 1;
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Inc(FLastTimeTick);
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FCurrentSeqNumber := FMinSeqNumber;
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FIsOverCost := True;
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Result := CalcId(FLastTimeTick);
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Exit;
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end;
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Result := CalcId(FLastTimeTick);
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end;
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function TSnowWorkerM1.CalcId(UseTimeTick: Int64): Int64;
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begin
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Result := ((UseTimeTick shl FTimestampShift) + (Int64(FWorkerId) shl FSeqBitLength) + Cardinal(FCurrentSeqNumber));
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Inc(FCurrentSeqNumber);
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end;
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function TSnowWorkerM1.CalcTurnBackId(UseTimeTick: Int64): Int64;
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begin
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Result := ((UseTimeTick shl FTimestampShift) + (Int64(FWorkerId) shl FSeqBitLength) + FTurnBackIndex);
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Dec(FTurnBackTimeTick);
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end;
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function TSnowWorkerM1.GetCurrentTimeTick(): Int64;
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var
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Millis: Int64;
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begin
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// Millis := DateTimeToUnix(Now(), False);
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Millis := GetMillisecondTimeStamp();
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Result := Millis - FBaseTime;
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end;
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function TSnowWorkerM1.GetNextTimeTick(): Int64;
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var
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TempTimeTicker: Int64;
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begin
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TempTimeTicker := GetCurrentTimeTick();
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while (TempTimeTicker <= FLastTimeTick) do
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begin
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// Sleep(1);
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TSpinWait.SpinUntil(
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function(): Boolean
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begin
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Result := False;
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end, 1);
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TempTimeTicker := GetCurrentTimeTick();
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end;
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Result := TempTimeTicker;
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end;
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function TSnowWorkerM1.NextId(): Int64;
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begin
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SyncLock.Enter;
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try
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if FIsOverCost then
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Result := NextOverCostId()
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else
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Result := NextNormalId();
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finally
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SyncLock.Leave;
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end;
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end;
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end.
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