Horde_Imap_Client_Utf7imap::Utf7ImapToUtf8 PHP Method

    public static function Utf7ImapToUtf8($str)
    {
        if ($str instanceof Horde_Imap_Client_Mailbox) {
            return $str->utf8;
        }
        $str = strval($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, 'UTF-8', 'UTF7-IMAP');
        }
        $p = '';
        $ptr =& self::$_index64;
        for ($i = 0, $u7len = strlen($str); $u7len > 0; ++$i, --$u7len) {
            $u7 = $str[$i];
            if ($u7 === '&') {
                $u7 = $str[++$i];
                if (--$u7len && $u7 === '-') {
                    $p .= '&';
                    continue;
                }
                $ch = 0;
                $k = 10;
                for (; $u7len > 0; ++$i, --$u7len) {
                    $u7 = $str[$i];
                    if (ord($u7) & 0x80 || ($b = $ptr[ord($u7)]) === -1) {
                        break;
                    }
                    if ($k > 0) {
                        $ch |= $b << $k;
                        $k -= 6;
                    } else {
                        $ch |= $b >> -$k;
                        if ($ch < 0x80) {
                            /* Printable US-ASCII */
                            if (0x20 <= $ch && $ch < 0x7f) {
                                throw new Horde_Imap_Client_Exception(Horde_Imap_Client_Translation::r("Error converting UTF7-IMAP string."), Horde_Imap_Client_Exception::UTF7IMAP_CONVERSION);
                            }
                            $p .= chr($ch);
                        } else {
                            if ($ch < 0x800) {
                                $p .= chr(0xc0 | $ch >> 6) . chr(0x80 | $ch & 0x3f);
                            } else {
                                $p .= chr(0xe0 | $ch >> 12) . chr(0x80 | $ch >> 6 & 0x3f) . chr(0x80 | $ch & 0x3f);
                            }
                        }
                        $ch = $b << 16 + $k & 0xffff;
                        $k += 10;
                    }
                }
                /* Non-zero or too many extra bits -OR-
                 * Base64 not properly terminated -OR-
                 * Adjacent Base64 sections. */
                if ($ch || $k < 6 || (!$u7len || $u7 !== '-') || $u7len > 2 && $str[$i + 1] === '&' && $str[$i + 2] !== '-') {
                    throw new Horde_Imap_Client_Exception(Horde_Imap_Client_Translation::r("Error converting UTF7-IMAP string."), Horde_Imap_Client_Exception::UTF7IMAP_CONVERSION);
                }
            } elseif (ord($u7) < 0x20 || ord($u7) >= 0x7f) {
                /* Not printable US-ASCII */
                throw new Horde_Imap_Client_Exception(Horde_Imap_Client_Translation::r("Error converting UTF7-IMAP string."), Horde_Imap_Client_Exception::UTF7IMAP_CONVERSION);
            } else {
                $p .= $u7;
            }
        }
        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;
     }
 }