uuid.pas

uuid.pas

{$mode objfpc}{$H+}

unit UUID;

interface

uses
  Classes, SysUtils, Math;

type
  TUUID = packed record
    TimeLow: LongWord;
    TimeMid: Word;
    TimeHiAndVersion: Word;
    ClockSeqHiAndReserved: Byte;
    ClockSeqLow: Byte;
    Node: array[0..5] of Byte;
  end;

function GenerateUUID: TUUID;
function UUIDToString(const UUID: TUUID): String;
function StringToUUID(const UUIDStr: String): TUUID;

implementation

function GenerateUUID: TUUID;
var
  Rand: TMemoryStream;
  Bytes: array[0..15] of Byte;
begin
  Rand := TMemoryStream.Create;
  try
    Rand.LoadFromFile('/dev/urandom');
    Rand.ReadBuffer(Bytes, SizeOf(Bytes));
  finally
    Rand.Free;
  end;

  Result.TimeLow := (Bytes[0] shl 24) or (Bytes[1] shl 16) or (Bytes[2] shl 8) or Bytes[3];
  Result.TimeMid := (Bytes[4] shl 8) or Bytes[5];
  Result.TimeHiAndVersion := (Bytes[6] shl 8) or Bytes[7];
  Result.ClockSeqHiAndReserved := Bytes[8];
  Result.ClockSeqLow := Bytes[9];
  Result.Node[0] := Bytes[10];
  Result.Node[1] := Bytes[11];
  Result.Node[2] := Bytes[12];
  Result.Node[3] := Bytes[13];
  Result.Node[4] := Bytes[14];
  Result.Node[5] := Bytes[15];
end;

function UUIDToString(const UUID: TUUID): String;
begin
  Result := Format('%.8x-%.4x-%.4x-%.2x%.2x-%.2x%.2x%.2x%.2x%.2x%.2x',
    [UUID.TimeLow, UUID.TimeMid, UUID.TimeHiAndVersion,
     UUID.ClockSeqHiAndReserved, UUID.ClockSeqLow,
     UUID.Node[0], UUID.Node[1], UUID.Node[2],
     UUID.Node[3], UUID.Node[4], UUID.Node[5]]);
end;


function StringToUUID(const UUIDStr: String): TUUID;
    var
      Parts: TStringList;
    begin
      Parts := TStringList.Create;
      try
        ExtractStrings(['-'], [' '], PChar(UUIDStr), Parts);
        Result.TimeLow := StrToInt('$' + Parts[0]);
        Result.TimeMid := StrToInt('$' + Parts[1]);
        Result.TimeHiAndVersion := StrToInt('$' + Parts[2]);
        Result.ClockSeqHiAndReserved := StrToInt('$' + Parts[3][1]);
        Result.ClockSeqLow := StrToInt('$' + Parts[3][2]);
        Result.Node[0] := StrToInt('$' + Parts[4][1] + Parts[4][2]);
        Result.Node[1] := StrToInt('$' + Parts[4][3] + Parts[4][4]);
        Result.Node[2] := StrToInt('$' + Parts[4][5] + Parts[4][6]);
        Result.Node[3] := StrToInt('$' + Parts[4][7] + Parts[4][8]);
        Result.Node[4] := StrToInt('$' + Parts[4][9] + Parts[4][10]);
        Result.Node[5] := StrToInt('$' + Parts[4][11] + Parts[4][12]);
      finally
        Parts.Free;
      end;
    end;
end.