TWriter/TReader und Stream

[Sprint]

Hier mal ein übertriebenes Beispiel:

Von einer String Variable in ein TMemoryStream und dann den TMemoryStream in TWriter schreiben:

Delphi-Quellcode:

procedure TForm1.Button1Click(Sender: TObject);
var
  Handle: Integer;
  HandleStream: THandleStream;
  MemoryStream: TMemoryStream;
  Writer: TWriter;
  S: String;
  Size: Integer;
begin

  Handle := FileCreate('M:\TEMP\TEST.TXT');
  if Handle <> -1 then
  begin
    HandleStream := THandleStream.Create(Handle);
    MemoryStream := TMemoryStream.Create;
    Writer := TWriter.Create(HandleStream, 4096);
    try
      S := 'TestString';
      MemoryStream.WriteBuffer(S[1], Length(S));
      MemoryStream.Position := 0;
      Size := MemoryStream.Size;
      Writer.WriteInteger(Size);
      Writer.Write(MemoryStream.Memory^, Size);
    finally
      Writer.Free;
      MemoryStream.Free;
      HandleStream.Free;
      FileClose(Handle);
    end;
  end;

end;

Und nun von TReader in TMemoryStream und dann in die Variable S:

Delphi-Quellcode:

procedure TForm1.Button2Click(Sender: TObject);
var
  Handle: Integer;
  HandleStream: THandleStream;
  MemoryStream: TMemoryStream;
  Reader: TReader;
  Size: Integer;
  S: String;
begin

  Handle := FileOpen('M:\TEMP\TEST.TXT', fmOpenRead);
  if Handle <> -1 then
  begin
    HandleStream := THandleStream.Create(Handle);
    MemoryStream := TMemoryStream.Create;
    Reader := TReader.Create(HandleStream, 4096);
    try
      Size := Reader.ReadInteger;
      MemoryStream.Size := Size;
      MemoryStream.Position := 0;
      Reader.Read(MemoryStream.Memory^, Size);
      MemoryStream.Position := 0;
      SetLength(S, Size);
      MemoryStream.Read(S[1], Size);
      ShowMessage(S);
    finally
      Reader.Free;
      MemoryStream.Free;
      HandleStream.Free;
      FileClose(Handle);
    end;
  end;

end;