function ReadFile(FileName: String): AnsiString;
var
  F :File;
  Buffer :AnsiString;
  Size :Integer;
  ReadBytes :Integer;
  DefaultFileMode:Byte;
begin
  Result := '';
  DefaultFileMode := FileMode;
  FileMode := 0;
  AssignFile(F, FileName);
  Reset(F, 1);

  if (IOResult = 0) then
  begin
    Size := FileSize(F);
    while (Size > 1024) do
    begin
      SetLength(Buffer, 1024);
      BlockRead(F, Buffer[1], 1024, ReadBytes);
      Result := Result + Buffer;
      Dec(Size, ReadBytes);
    end;
    SetLength(Buffer, Size);
    BlockRead(F, Buffer[1], Size);
    Result := Result + Buffer;
    CloseFile(F);
  end;

  FileMode := DefaultFileMode;
end;