voku / portable-utf8

   */

  public static function removeBOM($str = '', $utf8 = true, $utf16 = true, $utf32 = true)

  {

    if ($utf8 === true) {

      // UTF-8

      /** @noinspection PhpUsageOfSilenceOperatorInspection */

      if (0 === strpos($str, @pack('CCC', 0xef, 0xbb, 0xbf)) || 0 === strpos($str, '')) {

        $str = substr($str, 3);

      }

    }

    if ($utf32 === true) {

      // UTF-32 (BE)

    if ($utf16 === true) {

      // UTF-16 (BE)

      /** @noinspection PhpUsageOfSilenceOperatorInspection */

      if (0 === strpos($str, @pack('CC', 0xfe, 0xff)) || 0 === strpos($str, 'þÿ')) {

        $str = substr($str, 2);

      }

      // UTF-16 (LE)

      /** @noinspection PhpUsageOfSilenceOperatorInspection */

      // UTF-16 (LE)

      /** @noinspection PhpUsageOfSilenceOperatorInspection */

      if (0 === strpos($str, @pack('CC', 0xff, 0xfe)) || 0 === strpos($str, 'ÿþ')) {

        $str = substr($str, 2);

      }

    }

    return $str;