Интерфейс факторизации уровня /dr/

type
  Factorizer = class;

  InterceptionResult = (ContinueFactorization, ContinueAndReport);
  Interception = class
    constructor Create(theFact: Factorizer);
    function Intercept: InterceptionResult;
    function GetReport: TObject;
    procedure Reported;
  private
    fact: Factorizer;
  end;

  Algorithm = interface
    function Factor(const n: BigInt; interception: Interception): BigInt;
    function CreateReport: TObject;
  end;

  Reporter = interface
    procedure Report(rep: TObject);
  end;

  PrimeStatus = (ValidPrime, StillNonPrime, DecompositionFailed);
  NumberDecomposition = array of record
    value: BigInt;
    times: integer;
    status: PrimeStatus;
  end;

  FactorizationStatus = (FactorizationReady, FactorizationInProgress,
    FactorizationCompleted, FactorizationStopped, FactorizationError);

  Factorizer = class
    constructor Create(useAlgo: Algorithm; useReporter: Reporter; completionCallback: TNotifyEvent);
    destructor Destroy; override;
    procedure Run(const value: BigInt);
    function Status: FactorizationStatus;
    function Decomposition: NumberDecomposition;
    function ErrorMessage: string;
    procedure Stop;
  private type
    FactorizationThread = class(TThread)
      constructor Create(theFact: Factorizer);
    protected
      procedure Execute; override;
    private
      fact: Factorizer;
    end;

  var
    cs: TRTLCriticalSection;
    algo: Algorithm;
    decomp: NumberDecomposition;
    _reporter: Reporter;
    _report: TObject;
    _status: FactorizationStatus;
    onComplete: TNotifyEvent;
    errmsg: string;
    thread: FactorizationThread;
    procedure Lock;
    procedure Unlock;
    function Intercept: InterceptionResult;
    procedure AddAnswer(const value: BigInt);
    procedure RemoveAnswer(const value: BigInt);
  end;
  EFactorizationStopped = class(Exception) end;