Getting "ÿþI" as output data when reading from a .log file using delphi

I am trying to read data from a .log file and process its contents. The log file is created by another application. When I use the readln command in Delphi and display the contents of the file in a memo, I only get the one line of data (ÿþI) from a file with over 6000 lines of data.

    procedure TForm1.Button1Click(Sender: TObject);
    Var
        F : TextFile;
        s : string;
    begin
        AssignFile(F, 'data.log');
        Reset开发者_Go百科(F);

        while not Eof(F) do
        begin
            Readln(F, s);
            Memo1.Lines.Add(s);
        end;
    end;

Does anyone know what the problem might be?

---

As Michael said, you are dealing with a UTF-16 encoded file, so you will have to load and decode it manually. There are various WideString-based TStringList-like classes floating around online, or Borland has its own implementation in the WideStrings unit, try using one of them instead of Pascal file I/O, eg:

procedure TForm1.Button1Click(Sender: TObject);
var
  SL : TWideStringList;
  I: Integer;
  s : string;
begin
  SL := TWideStringList.Create;
  try
    SL.LoadFromFile('data.log');
    Memo1.Lines.BeginUpdate;
    try
      for I := 0 to SL.Count-1 do
        Memo1.Lines.Add(SL[I]);
    finally
      Memo1.Lines.EndUpdate;
    end;
  finally
    SL.Free;
  end;
end; 

Or:

uses
  .., WideStrings;

procedure TForm1.Button1Click(Sender: TObject);
var
  SL : TWideStringList;
begin
  SL := TWideStringList.Create;
  try
    SL.LoadFromFile('data.log');
    Memo1.Lines.Assign(SL);
  finally
    SL.Free;
  end;
end; 

Alternatively, install a copy of TNTWare or TMS, which both have Unicode-enabled components. Then you should be able to just LoadFromFile() the .log file directly into whicher Unicode Memo component you chose to use.

---

You're dealing with a UTF-16 file (as evidenced by the first two characters), and Delphi 2007 is not prepared for that, so it stops reading on the first $0 byte, because Readln thinks the line ends there.

You'll need to use a different method of reading the file, and you'll have to read into a WideString (and probably convert that to a string). Since Delphi 2007 is not properly Unicode-capable, I think you'll also have to do your own line splitting, but I don't have that available here, so I'm not completely certain.

---

As mentioned in my comment to Remy's answer, there is a TWideStrings/TWideStringList declared in WideStrings:

uses WidesStrings;
//...
var
  Ws: TWideStrings;
  s: string;
  i: Integer;
begin
  Ws := TWideStringList.Create;
  try
    ws.LoadFromFile('C:\temp\UniTest.txt');
    for i := 0 to ws.Count - 1 do
    begin
      s := ws[i];
      Memo1.Lines.Add(s);
    end;
  finally
    ws.Free;
  end;
end;

Note however that is isn't a TStrings descendant, so it can't be directly assigned to TStrings properties like TMemo.Lines, you have to add them one by one.

It also doesn't seem to handle the BOM (your ÿþ) or big-endian encoding