delphi GUID单元

unit uGUID;

{采用的开源算法 https://github.com/martinusso/ulid 加已改造成32位有序GUID}

interface

uses

DateUtils, SysUtils, Windows;

//有序的32位id

function GetULID(QDataTime:TDateTime):string;

function EncodeTime(Time:Int64):string;

function EncodeRandom: string;

implementation

const

ENCODING: array[0..31] of string = ('0', '1', '2', '3', '4', '5', '6', '7', '8', '9',

'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K',

'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'V', 'W', 'X',

'Y', 'Z'); // Crockford's Base32

ENCODING_LENGTH = Length(ENCODING);

function GetULID(QDataTime:TDateTime): string;

var vInt64:Int64;

begin

vInt64 := DateUtils.MilliSecondsBetween(QDataTime, UnixDateDelta);

Result := EncodeTime(vInt64) + EncodeRandom;

end;

function EncodeRandom: string;

const

ENCODED_RANDOM_LENGTH = 22;

var

I: Word;

Rand: Integer;

begin

Result := '';

for I := ENCODED_RANDOM_LENGTH downto 1 do

begin

Rand := Trunc(ENCODING_LENGTH * Random);

Result := ENCODING[Rand] + Result;

end;

function EncodeTime(Time: Int64): string;

const

ENCODED_TIME_LENGTH = 10;

var

I: Word;

M: Integer;

begin

Result := '';

for I := ENCODED_TIME_LENGTH downto 1 do

begin

M := (Time mod ENCODING_LENGTH);

Result := ENCODING[M] + Result;

Time := Trunc((Time - M) / ENCODING_LENGTH);

end;

end.

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