delphi版雪花算法

//Delphi版雪花算法

//作者：不得闲

//QQ: 75492895

unit DxSnowflake;

interface

uses System.SysUtils,System.SyncObjs,System.Generics.Collections,System.DateUtils;

type

TWorkerID = 0..1023;

TDxSnowflake = class

private

FWorkerID: TWorkerID;

FLocker: TCriticalSection;

fTime: Int64;

fstep: int64;

public

constructor Create;

destructor Destroy;override;

property WorkerID: TWorkerID read FWorkerID write FWorkerID;

function Generate: Int64;

end;

implementation

const

Epoch: int64 = 1539615188000; //北京时间2018-10-15号

//工作站的节点位数

WorkerNodeBits:Byte = 10;

//序列号的节点数

StepBits: Byte = 12;

timeShift: Byte = 22;

nodeShift: Byte = 12;

var

WorkerNodeMax: int64;

nodeMask:int64;

stepMask:int64;

procedure InitNodeInfo;

begin

WorkerNodeMax := -1 xor (-1 shl WorkerNodeBits);

nodeMask := WorkerNodeMax shl StepBits;

stepMask := -1 xor (-1 shl StepBits);

end;

{ TDxSnowflake }

constructor TDxSnowflake.Create;

begin

FLocker := TCriticalSection.Create;

end;

destructor TDxSnowflake.Destroy;

begin

FLocker.Free;

inherited;

end;

function TDxSnowflake.Generate: Int64;

var

curtime: Int64;

begin

FLocker.Acquire;

try

curtime := DateTimeToUnix(Now) * 1000;

if curtime = fTime then

begin

fstep := (fstep + 1) and stepMask;

if fstep = 0 then

begin

while curtime <= fTime do

curtime := DateTimeToUnix(Now) * 1000;

end;

end

else fstep := 0;

fTime := curtime;

Result := (curtime - Epoch) shl timeShift or FWorkerID shl nodeShift or fstep;

finally

FLocker.Release;

end;

initialization

InitNodeInfo;

end.

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