const

  IS_TEXT_UNICODE_ASCII16 = $1;

  IS_TEXT_UNICODE_REVERSE_ASCII16 = $10;

  IS_TEXT_UNICODE_STATISTICS = $2;

  IS_TEXT_UNICODE_REVERSE_STATISTICS = $20;

  IS_TEXT_UNICODE_CONTROLS = $4;

  IS_TEXT_UNICODE_REVERSE_CONTROLS = $40;

  IS_TEXT_UNICODE_SIGNATURE = $8;

  IS_TEXT_UNICODE_REVERSE_SIGNATURE = $80;

  IS_TEXT_UNICODE_ILLEGAL_CHARS = $100;

  IS_TEXT_UNICODE_ODD_LENGTH = $200;

  IS_TEXT_UNICODE_DBCS_LEADBYTE = $400;

  IS_TEXT_UNICODE_NULL_BYTES = $1000;

  IS_TEXT_UNICODE_UNICODE_MASK = $F;

  IS_TEXT_UNICODE_REVERSE_MASK = $F0;

  IS_TEXT_UNICODE_NOT_UNICODE_MASK = $F00;

  IS_TEXT_UNICODE_NOT_ASCII_MASK = $F000;

function DecordUtf8: String;

var

  MyOpt : Integer;

  Text: String;

begin

  Text := 'WWWWWWWWWWWW'; //可以为从文件中读出来的字符

  MyOpt := IS_TEXT_UNICODE_UNICODE_MASK;

  if IsTextUnicode(PChar(Text), length(Text), @MyOpt) then

    Text:= Utf8Decode(Text);

  Result := Text;

end;