Horde_Imap_Client_Utf7imap::Utf8ToUtf7Imap PHP Method

    public static function Utf8ToUtf7Imap($str, $force = true)
    {
        if ($str instanceof Horde_Imap_Client_Mailbox) {
            return $str->utf7imap;
        }
        $str = strval($str);
        /* No need to do conversion if all chars are in US-ASCII range or if
         * no ampersand is present. But will assume that an already encoded
         * ampersand means string is in UTF7-IMAP already. */
        if (!$force && !preg_match('/[\\x80-\\xff]|&$|&(?![,+A-Za-z0-9]*-)/', $str)) {
            return $str;
        }
        /* Try mbstring, if available, which should be faster. Don't use the
         * IMAP utf7_* functions because they are known to be buggy. */
        if (is_null(self::$_mbstring)) {
            self::$_mbstring = extension_loaded('mbstring');
        }
        if (self::$_mbstring) {
            return @mb_convert_encoding($str, 'UTF7-IMAP', 'UTF-8');
        }
        $u8len = strlen($str);
        $i = 0;
        $base64 = false;
        $p = '';
        $ptr =& self::$_base64;
        while ($u8len) {
            $u8 = $str[$i];
            $c = ord($u8);
            if ($c < 0x80) {
                $ch = $c;
                $n = 0;
            } elseif ($c < 0xc2) {
                throw new Horde_Imap_Client_Exception(Horde_Imap_Client_Translation::r("Error converting UTF7-IMAP string."), Horde_Imap_Client_Exception::UTF7IMAP_CONVERSION);
            } elseif ($c < 0xe0) {
                $ch = $c & 0x1f;
                $n = 1;
            } elseif ($c < 0xf0) {
                $ch = $c & 0xf;
                $n = 2;
            } elseif ($c < 0xf8) {
                $ch = $c & 0x7;
                $n = 3;
            } elseif ($c < 0xfc) {
                $ch = $c & 0x3;
                $n = 4;
            } elseif ($c < 0xfe) {
                $ch = $c & 0x1;
                $n = 5;
            } else {
                throw new Horde_Imap_Client_Exception(Horde_Imap_Client_Translation::r("Error converting UTF7-IMAP string."), Horde_Imap_Client_Exception::UTF7IMAP_CONVERSION);
            }
            if ($n > --$u8len) {
                throw new Horde_Imap_Client_Exception(Horde_Imap_Client_Translation::r("Error converting UTF7-IMAP string."), Horde_Imap_Client_Exception::UTF7IMAP_CONVERSION);
            }
            ++$i;
            for ($j = 0; $j < $n; ++$j) {
                $o = ord($str[$i + $j]);
                if (($o & 0xc0) !== 0x80) {
                    throw new Horde_Imap_Client_Exception(Horde_Imap_Client_Translation::r("Error converting UTF7-IMAP string."), Horde_Imap_Client_Exception::UTF7IMAP_CONVERSION);
                }
                $ch = $ch << 6 | $o & 0x3f;
            }
            if ($n > 1 && !($ch >> $n * 5 + 1)) {
                throw new Horde_Imap_Client_Exception(Horde_Imap_Client_Translation::r("Error converting UTF7-IMAP string."), Horde_Imap_Client_Exception::UTF7IMAP_CONVERSION);
            }
            $i += $n;
            $u8len -= $n;
            if ($ch < 0x20 || $ch >= 0x7f) {
                if (!$base64) {
                    $p .= '&';
                    $base64 = true;
                    $b = 0;
                    $k = 10;
                }
                if ($ch & ~0xffff) {
                    $ch = 0xfffe;
                }
                $p .= $ptr[$b | $ch >> $k];
                $k -= 6;
                for (; $k >= 0; $k -= 6) {
                    $p .= $ptr[$ch >> $k & 0x3f];
                }
                $b = $ch << -$k & 0x3f;
                $k += 16;
            } else {
                if ($base64) {
                    if ($k > 10) {
                        $p .= $ptr[$b];
                    }
                    $p .= '-';
                    $base64 = false;
                }
                $p .= chr($ch);
                if (chr($ch) === '&') {
                    $p .= '-';
                }
            }
        }
        if ($base64) {
            if ($k > 10) {
                $p .= $ptr[$b];
            }
            $p .= '-';
        }
        return $p;
    }

 /**
  */
 public function __get($name)
 {
     switch ($name) {
         case 'list_escape':
             return preg_replace("/\\*+/", '%', $this->utf8);
         case 'utf7imap':
             if (!isset($this->_utf7imap)) {
                 $n = Horde_Imap_Client_Utf7imap::Utf8ToUtf7Imap($this->_utf8);
                 $this->_utf7imap = $n == $this->_utf8 ? true : $n;
             }
             return $this->_utf7imap === true ? $this->_utf8 : $this->_utf7imap;
         case 'utf8':
             if (!isset($this->_utf8)) {
                 $this->_utf8 = Horde_Imap_Client_Utf7imap::Utf7ImapToUtf8($this->_utf7imap);
                 if ($this->_utf8 == $this->_utf7imap) {
                     $this->_utf7imap = true;
                 }
             }
             return $this->_utf8;
     }
 }