lazarus新的判断字符串是否为UTF8

调用IsStringUTF8来判断string是否包含UTF8（中文）；

procedure TForm1.Button1Click(Sender: TObject);
begin
  if IsStringUTF8(edit1.Text)  then
     memo1.Lines.Add(s+'--包含中文')
  else
     memo1.Lines.Add(s+'--包含不中文');
end;

function IsStringUTF8(strtmp: string): Boolean;
var
  nBytes: byte;
  chr: byte;
  bAllAscii: Boolean;
  i: Integer;
  lengths:integer;
  str:PChar;
begin
  lengths:=length(strtmp);
  nBytes := 0;
  bAllAscii := TRUE;
  for i := 1 to lengths do
  begin
    chr := ord(strtmp[i]);
    if (chr and $80) <> 0 then
      bAllAscii := FALSE;

    if nBytes = 0 then
    begin
      if chr >= $80 then
      begin
        if chr >= $FC then
          nBytes := 6
        else if chr >= $F8 then
          nBytes := 5
        else if chr >= $F0 then
          nBytes := 4
        else if chr >= $E0 then
          nBytes := 3
        else if chr >= $C0 then
          nBytes := 2
        else
          Exit(FALSE);

        Dec(nBytes);
      end;
    end
    else
    begin
      if (chr and $C0) <> $80 then
        Exit(FALSE);

      Dec(nBytes);
    end;
  end;

  if nBytes > 0 then
    Exit(FALSE);

  if bAllAscii then
    Exit(FALSE);

  Result := TRUE;
end;