source: subversion/trunk/roundcubemail/program/include/rcube_imap_generic.php @ 4088

<?php

/*
 +-----------------------------------------------------------------------+
 | program/include/rcube_imap_generic.php                                |
 |                                                                       |
 | This file is part of the Roundcube Webmail client                     |
 | Copyright (C) 2005-2010, Roundcube Dev. - Switzerland                 |
 | Licensed under the GNU GPL                                            |
 |                                                                       |
 | PURPOSE:                                                              |
 |   Provide alternative IMAP library that doesn't rely on the standard  |
 |   C-Client based version. This allows to function regardless          |
 |   of whether or not the PHP build it's running on has IMAP            |
 |   functionality built-in.                                             |
 |                                                                       |
 |   Based on Iloha IMAP Library. See http://ilohamail.org/ for details  |
 |                                                                       |
 +-----------------------------------------------------------------------+
 | Author: Aleksander Machniak <alec@alec.pl>                            |
 | Author: Ryo Chijiiwa <Ryo@IlohaMail.org>                              |
 +-----------------------------------------------------------------------+

 $Id$

*/


/**
 * Struct representing an e-mail message header
 *
 * @package    Mail
 * @author     Aleksander Machniak <alec@alec.pl>
 */
class rcube_mail_header
{
        public $id;
        public $uid;
        public $subject;
        public $from;
        public $to;
        public $cc;
        public $replyto;
        public $in_reply_to;
        public $date;
        public $messageID;
        public $size;
        public $encoding;
        public $charset;
        public $ctype;
        public $flags;
        public $timestamp;
        public $f;
        public $body_structure;
        public $internaldate;
        public $references;
        public $priority;
        public $mdn_to;
        public $mdn_sent = false;
        public $is_draft = false;
        public $seen = false;
        public $deleted = false;
        public $recent = false;
        public $answered = false;
        public $forwarded = false;
        public $junk = false;
        public $flagged = false;
        public $has_children = false;
        public $depth = 0;
        public $unread_children = 0;
        public $others = array();
}

// For backward compatibility with cached messages (#1486602)
class iilBasicHeader extends rcube_mail_header
{
}

/**
 * PHP based wrapper class to connect to an IMAP server
 *
 * @package    Mail
 * @author     Aleksander Machniak <alec@alec.pl>
 */
class rcube_imap_generic
{
    public $error;
    public $errornum;
        public $message;
        public $rootdir;
        public $delimiter;
        public $permanentflags = array();
    public $flags = array(
        'SEEN'     => '\\Seen',
        'DELETED'  => '\\Deleted',
        'RECENT'   => '\\Recent',
        'ANSWERED' => '\\Answered',
        'DRAFT'    => '\\Draft',
        'FLAGGED'  => '\\Flagged',
        'FORWARDED' => '$Forwarded',
        'MDNSENT'  => '$MDNSent',
        '*'        => '\\*',
    );

        private $exists;
        private $recent;
    private $selected;
        private $fp;
        private $host;
        private $logged = false;
        private $capability = array();
        private $capability_readed = false;
    private $prefs;

    const ERROR_OK = 0;
    const ERROR_NO = -1;
    const ERROR_BAD = -2;
    const ERROR_BYE = -3;
    const ERROR_COMMAND = -5;
    const ERROR_UNKNOWN = -4;

    /**
     * Object constructor
     */
    function __construct()
    {
    }

    function putLine($string, $endln=true)
    {
        if (!$this->fp)
            return false;

                if (!empty($this->prefs['debug_mode'])) {
                write_log('imap', 'C: '. rtrim($string));
            }

        $res = fwrite($this->fp, $string . ($endln ? "\r\n" : ''));

                if ($res === false) {
                @fclose($this->fp);
                $this->fp = null;
                }

        return $res;
    }

    // $this->putLine replacement with Command Continuation Requests (RFC3501 7.5) support
    function putLineC($string, $endln=true)
    {
        if (!$this->fp)
            return false;

            if ($endln)
                    $string .= "\r\n";

            $res = 0;
            if ($parts = preg_split('/(\{[0-9]+\}\r\n)/m', $string, -1, PREG_SPLIT_DELIM_CAPTURE)) {
                    for ($i=0, $cnt=count($parts); $i<$cnt; $i++) {
                            if (preg_match('/^\{[0-9]+\}\r\n$/', $parts[$i+1])) {
                                    $bytes = $this->putLine($parts[$i].$parts[$i+1], false);
                    if ($bytes === false)
                        return false;
                    $res += $bytes;
                                    $line = $this->readLine(1000);
                                    // handle error in command
                                    if ($line[0] != '+')
                                            return false;
                                    $i++;
                            }
                            else {
                                    $bytes = $this->putLine($parts[$i], false);
                    if ($bytes === false)
                        return false;
                    $res += $bytes;
                }
                    }
            }

            return $res;
    }

    function readLine($size=1024)
    {
                $line = '';

            if (!$this->fp) {
                return NULL;
            }

            if (!$size) {
                    $size = 1024;
            }

            do {
                    if (feof($this->fp)) {
                            return $line ? $line : NULL;
                    }

                $buffer = fgets($this->fp, $size);

                if ($buffer === false) {
                @fclose($this->fp);
                $this->fp = null;
                        break;
                }
                    if (!empty($this->prefs['debug_mode'])) {
                            write_log('imap', 'S: '. rtrim($buffer));
                }
            $line .= $buffer;
            } while ($buffer[strlen($buffer)-1] != "\n");

            return $line;
    }

    function multLine($line, $escape=false)
    {
            $line = rtrim($line);
            if (preg_match('/\{[0-9]+\}$/', $line)) {
                    $out = '';

                    preg_match_all('/(.*)\{([0-9]+)\}$/', $line, $a);
                    $bytes = $a[2][0];
                    while (strlen($out) < $bytes) {
                            $line = $this->readBytes($bytes);
                            if ($line === NULL)
                                    break;
                            $out .= $line;
                    }

                    $line = $a[1][0] . '"' . ($escape ? $this->Escape($out) : $out) . '"';
            }

        return $line;
    }

    function readBytes($bytes)
    {
            $data = '';
            $len  = 0;
            while ($len < $bytes && !feof($this->fp))
            {
                    $d = fread($this->fp, $bytes-$len);
                    if (!empty($this->prefs['debug_mode'])) {
                            write_log('imap', 'S: '. $d);
            }
            $data .= $d;
                    $data_len = strlen($data);
                    if ($len == $data_len) {
                    break; // nothing was read -> exit to avoid apache lockups
                }
                $len = $data_len;
            }

            return $data;
    }

    // don't use it in loops, until you exactly know what you're doing
    function readReply(&$untagged=null)
    {
            do {
                    $line = trim($this->readLine(1024));
            // store untagged response lines
                    if ($line[0] == '*')
                $untagged[] = $line;
            } while ($line[0] == '*');

        if ($untagged)
            $untagged = join("\n", $untagged);

            return $line;
    }

    function parseResult($string, $err_prefix='')
    {
            if (preg_match('/^[a-z0-9*]+ (OK|NO|BAD|BYE)(.*)$/i', trim($string), $matches)) {
                    $res = strtoupper($matches[1]);
            $str = trim($matches[2]);

                    if ($res == 'OK') {
                            return self::ERROR_OK;
                    } else if ($res == 'NO') {
                $this->errornum = self::ERROR_NO;
                    } else if ($res == 'BAD') {
                            $this->errornum = self::ERROR_BAD;
                    } else if ($res == 'BYE') {
                @fclose($this->fp);
                $this->fp = null;
                            $this->errornum = self::ERROR_BYE;
                    }

            if ($str)
                $this->error = $err_prefix ? $err_prefix.$str : $str;

                return $this->errornum;
            }
            return self::ERROR_UNKNOWN;
    }

    private function set_error($code, $msg='')
    {
        $this->errornum = $code;
        $this->error    = $msg;
    }

    // check if $string starts with $match (or * BYE/BAD)
    function startsWith($string, $match, $error=false, $nonempty=false)
    {
            $len = strlen($match);
            if ($len == 0) {
                    return false;
            }
        if (!$this->fp) {
            return true;
        }
            if (strncmp($string, $match, $len) == 0) {
                    return true;
            }
            if ($error && preg_match('/^\* (BYE|BAD) /i', $string, $m)) {
            if (strtoupper($m[1]) == 'BYE') {
                @fclose($this->fp);
                $this->fp = null;
            }
                    return true;
            }
        if ($nonempty && !strlen($string)) {
            return true;
        }
            return false;
    }

    function getCapability($name)
    {
            if (in_array($name, $this->capability)) {
                    return true;
            }
            else if ($this->capability_readed) {
                    return false;
            }

            // get capabilities (only once) because initial
            // optional CAPABILITY response may differ
            $this->capability = array();

            if (!$this->putLine("cp01 CAPABILITY")) {
            return false;
        }
            do {
                    $line = trim($this->readLine(1024));
                if (preg_match('/^\* CAPABILITY (.+)/i', $line, $matches)) {
                        $this->capability = explode(' ', strtoupper($matches[1]));
                }
            } while (!$this->startsWith($line, 'cp01', true));

            $this->capability_readed = true;

            if (in_array($name, $this->capability)) {
                    return true;
            }

            return false;
    }

    function clearCapability()
    {
            $this->capability = array();
            $this->capability_readed = false;
    }

    function authenticate($user, $pass, $encChallenge)
    {
        $ipad = '';
        $opad = '';

        // initialize ipad, opad
        for ($i=0; $i<64; $i++) {
            $ipad .= chr(0x36);
            $opad .= chr(0x5C);
        }

        // pad $pass so it's 64 bytes
        $padLen = 64 - strlen($pass);
        for ($i=0; $i<$padLen; $i++) {
            $pass .= chr(0);
        }

        // generate hash
        $hash  = md5($this->_xor($pass,$opad) . pack("H*", md5($this->_xor($pass, $ipad) . base64_decode($encChallenge))));

        // generate reply
        $reply = base64_encode($user . ' ' . $hash);

        // send result, get reply
        $this->putLine($reply);
        $line = $this->readLine(1024);

        // process result
        $result = $this->parseResult($line);
        if ($result == self::ERROR_OK) {
            return $this->fp;
        }

        $this->error = "Authentication for $user failed (AUTH): $line";

        return $result;
    }

    function login($user, $password)
    {
        $this->putLine('a001 LOGIN "'.$this->escape($user).'" "'.$this->escape($password).'"');

        $line = $this->readReply($untagged);

        // re-set capabilities list if untagged CAPABILITY response provided
            if (preg_match('/\* CAPABILITY (.+)/i', $untagged, $matches)) {
                    $this->capability = explode(' ', strtoupper($matches[1]));
            }

        // process result
        $result = $this->parseResult($line);

        if ($result == self::ERROR_OK) {
            return $this->fp;
        }

        @fclose($this->fp);
        $this->fp    = false;
        $this->error = "Authentication for $user failed (LOGIN): $line";

        return $result;
    }

    function getNamespace()
    {
            if (isset($this->prefs['rootdir']) && is_string($this->prefs['rootdir'])) {
                $this->rootdir = $this->prefs['rootdir'];
                    return true;
            }

            if (!is_array($data = $this->_namespace())) {
                return false;
            }

            $user_space_data = $data[0];
            if (!is_array($user_space_data)) {
                return false;
            }

            $first_userspace = $user_space_data[0];
            if (count($first_userspace)!=2) {
                return false;
            }

            $this->rootdir            = $first_userspace[0];
            $this->delimiter          = $first_userspace[1];
            $this->prefs['rootdir']   = substr($this->rootdir, 0, -1);
            $this->prefs['delimiter'] = $this->delimiter;

            return true;
    }


    /**
     * Gets the delimiter, for example:
     * INBOX.foo -> .
     * INBOX/foo -> /
     * INBOX\foo -> \
     *
     * @return mixed A delimiter (string), or false.
     * @see connect()
     */
    function getHierarchyDelimiter()
    {
            if ($this->delimiter) {
                return $this->delimiter;
            }
            if (!empty($this->prefs['delimiter'])) {
            return ($this->delimiter = $this->prefs['delimiter']);
            }

            $delimiter = false;

            // try (LIST "" ""), should return delimiter (RFC2060 Sec 6.3.8)
            if (!$this->putLine('ghd LIST "" ""')) {
                return false;
            }

            do {
                    $line = $this->readLine(1024);
                    if (preg_match('/^\* LIST \([^\)]*\) "*([^"]+)"* ""/', $line, $m)) {
                $delimiter = $this->unEscape($m[1]);
                    }
            } while (!$this->startsWith($line, 'ghd', true, true));

            if (strlen($delimiter)>0) {
                return $delimiter;
            }

            // if that fails, try namespace extension
            // try to fetch namespace data
            if (!is_array($data = $this->_namespace())) {
            return false;
        }

            // extract user space data (opposed to global/shared space)
            $user_space_data = $data[0];
            if (!is_array($user_space_data)) {
                return false;
            }

            // get first element
            $first_userspace = $user_space_data[0];
            if (!is_array($first_userspace)) {
                return false;
            }

            // extract delimiter
            $delimiter = $first_userspace[1];

            return $delimiter;
    }

    function _namespace()
    {
        if (!$this->getCapability('NAMESPACE')) {
                return false;
            }

            if (!$this->putLine("ns1 NAMESPACE")) {
            return false;
        }

            do {
                    $line = $this->readLine(1024);
                    if (preg_match('/^\* NAMESPACE/', $line)) {
                            $i = 0;
                            $data = $this->parseNamespace(substr($line,11), $i, 0, 0);
                    }
            } while (!$this->startsWith($line, 'ns1', true, true));

            if (!is_array($data)) {
                return false;
            }

        return $data;
    }

    function connect($host, $user, $password, $options=null)
    {
            // set options
            if (is_array($options)) {
            $this->prefs = $options;
        }
        // set auth method
        if (!empty($this->prefs['auth_method'])) {
            $auth_method = strtoupper($this->prefs['auth_method']);
            } else {
                $auth_method = 'CHECK';
        }

            $message = "INITIAL: $auth_method\n";

            $result = false;

            // initialize connection
            $this->error    = '';
            $this->errornum = self::ERROR_OK;
            $this->selected = '';
            $this->user     = $user;
            $this->host     = $host;
        $this->logged   = false;

            // check input
            if (empty($host)) {
                    $this->set_error(self::ERROR_BAD, "Empty host");
                    return false;
            }
        if (empty($user)) {
                $this->set_error(self::ERROR_NO, "Empty user");
                return false;
            }
            if (empty($password)) {
                $this->set_error(self::ERROR_NO, "Empty password");
                    return false;
            }

            if (!$this->prefs['port']) {
                    $this->prefs['port'] = 143;
            }
            // check for SSL
            if ($this->prefs['ssl_mode'] && $this->prefs['ssl_mode'] != 'tls') {
                    $host = $this->prefs['ssl_mode'] . '://' . $host;
            }

        // Connect
        if ($this->prefs['timeout'] > 0)
                $this->fp = @fsockopen($host, $this->prefs['port'], $errno, $errstr, $this->prefs['timeout']);
            else
                $this->fp = @fsockopen($host, $this->prefs['port'], $errno, $errstr);

            if (!$this->fp) {
                $this->set_error(self::ERROR_BAD, sprintf("Could not connect to %s:%d: %s", $host, $this->prefs['port'], $errstr));
                    return false;
            }

        if ($this->prefs['timeout'] > 0)
                stream_set_timeout($this->fp, $this->prefs['timeout']);

            $line = trim(fgets($this->fp, 8192));

            if ($this->prefs['debug_mode'] && $line) {
                    write_log('imap', 'S: '. $line);
        }

            // Connected to wrong port or connection error?
            if (!preg_match('/^\* (OK|PREAUTH)/i', $line)) {
                    if ($line)
                            $this->error = sprintf("Wrong startup greeting (%s:%d): %s", $host, $this->prefs['port'], $line);
                    else
                            $this->error = sprintf("Empty startup greeting (%s:%d)", $host, $this->prefs['port']);
                $this->errornum = self::ERROR_BAD;
                return false;
            }

            // RFC3501 [7.1] optional CAPABILITY response
            if (preg_match('/\[CAPABILITY ([^]]+)\]/i', $line, $matches)) {
                    $this->capability = explode(' ', strtoupper($matches[1]));
            }

            $this->message .= $line;

            // TLS connection
            if ($this->prefs['ssl_mode'] == 'tls' && $this->getCapability('STARTTLS')) {
                if (version_compare(PHP_VERSION, '5.1.0', '>=')) {
                $this->putLine("tls0 STARTTLS");

                            $line = $this->readLine(4096);
                if (!preg_match('/^tls0 OK/', $line)) {
                                    $this->set_error(self::ERROR_BAD, "Server responded to STARTTLS with: $line");
                    return false;
                }

                            if (!stream_socket_enable_crypto($this->fp, true, STREAM_CRYPTO_METHOD_TLS_CLIENT)) {
                                    $this->set_error(self::ERROR_BAD, "Unable to negotiate TLS");
                                    return false;
                            }

                            // Now we're authenticated, capabilities need to be reread
                            $this->clearCapability();
                }
            }

            $orig_method = $auth_method;

            if ($auth_method == 'CHECK') {
                    // check for supported auth methods
                    if ($this->getCapability('AUTH=CRAM-MD5') || $this->getCapability('AUTH=CRAM_MD5')) {
                            $auth_method = 'AUTH';
                    }
                    else {
                            // default to plain text auth
                            $auth_method = 'PLAIN';
                    }
            }

            if ($auth_method == 'AUTH') {
                    // do CRAM-MD5 authentication
                    $this->putLine("a000 AUTHENTICATE CRAM-MD5");
                    $line = trim($this->readLine(1024));

                    if ($line[0] == '+') {
                            // got a challenge string, try CRAM-MD5
                            $result = $this->authenticate($user, $password, substr($line,2));

                            // stop if server sent BYE response
                            if ($result == self::ERROR_BYE) {
                                    return false;
                            }
                    }

                    if (!is_resource($result) && $orig_method == 'CHECK') {
                            $auth_method = 'PLAIN';
                    }
            }

            if ($auth_method == 'PLAIN') {
                    // do plain text auth
                    $result = $this->login($user, $password);
            }

            if (is_resource($result)) {
            if ($this->prefs['force_caps']) {
                            $this->clearCapability();
            }
                    $this->getNamespace();
            $this->logged = true;

                    return true;
            } else {
                    return false;
            }
    }

    function connected()
    {
                return ($this->fp && $this->logged) ? true : false;
    }

    function close()
    {
            if ($this->logged && $this->putLine("I LOGOUT")) {
                    if (!feof($this->fp))
                            fgets($this->fp, 1024);
            }
                @fclose($this->fp);
                $this->fp = false;
    }

    function select($mailbox)
    {
            if (empty($mailbox)) {
                    return false;
            }
            if ($this->selected == $mailbox) {
                    return true;
            }

        $command = "sel1 SELECT \"".$this->escape($mailbox).'"';

            if (!$this->putLine($command)) {
            $this->set_error(self::ERROR_COMMAND, "Unable to send command: $command");
            return false;
        }

                do {
                        $line = rtrim($this->readLine(512));

                        if (preg_match('/^\* ([0-9]+) (EXISTS|RECENT)$/', $line, $m)) {
                            $token = strtolower($m[2]);
                            $this->$token = (int) $m[1];
                        }
                        else if (preg_match('/\[?PERMANENTFLAGS\s+\(([^\)]+)\)\]/U', $line, $match)) {
                            $this->permanentflags = explode(' ', $match[1]);
                        }
                } while (!$this->startsWith($line, 'sel1', true, true));

        if ($this->parseResult($line, 'SELECT: ') == self::ERROR_OK) {
                    $this->selected = $mailbox;
                        return true;
                }

        return false;
    }

    function checkForRecent($mailbox)
    {
            if (empty($mailbox)) {
                    $mailbox = 'INBOX';
            }

            $this->select($mailbox);
            if ($this->selected == $mailbox) {
                    return $this->recent;
            }

            return false;
    }

    function countMessages($mailbox, $refresh = false)
    {
            if ($refresh) {
                    $this->selected = '';
            }

            $this->select($mailbox);
            if ($this->selected == $mailbox) {
                    return $this->exists;
            }

        return false;
    }

    function sort($mailbox, $field, $add='', $is_uid=FALSE, $encoding = 'US-ASCII')
    {
            $field = strtoupper($field);
            if ($field == 'INTERNALDATE') {
                $field = 'ARRIVAL';
            }

            $fields = array('ARRIVAL' => 1,'CC' => 1,'DATE' => 1,
            'FROM' => 1, 'SIZE' => 1, 'SUBJECT' => 1, 'TO' => 1);

            if (!$fields[$field]) {
                return false;
            }

            /*  Do "SELECT" command */
            if (!$this->select($mailbox)) {
                return false;
            }

            $is_uid = $is_uid ? 'UID ' : '';

            // message IDs
            if (is_array($add))
                    $add = $this->compressMessageSet(join(',', $add));

            $command  = "s ".$is_uid."SORT ($field) $encoding ALL";
            $line     = '';
            $data     = '';

            if (!empty($add))
                $command .= ' '.$add;

            if (!$this->putLineC($command)) {
            $this->set_error(self::ERROR_COMMAND, "Unable to send command: $command");
                return false;
            }
            do {
                    $line = rtrim($this->readLine());
                    if (!$data && preg_match('/^\* SORT/', $line)) {
                            $data .= substr($line, 7);
                } else if (preg_match('/^[0-9 ]+$/', $line)) {
                            $data .= $line;
                    }
            } while (!$this->startsWith($line, 's ', true, true));

            $result_code = $this->parseResult($line, 'SORT: ');
            if ($result_code != self::ERROR_OK) {
            return false;
            }

            return preg_split('/\s+/', $data, -1, PREG_SPLIT_NO_EMPTY);
    }

    function fetchHeaderIndex($mailbox, $message_set, $index_field='', $skip_deleted=true, $uidfetch=false)
    {
            if (is_array($message_set)) {
                    if (!($message_set = $this->compressMessageSet(join(',', $message_set))))
                            return false;
            } else {
                    list($from_idx, $to_idx) = explode(':', $message_set);
                    if (empty($message_set) ||
                            (isset($to_idx) && $to_idx != '*' && (int)$from_idx > (int)$to_idx)) {
                            return false;
                    }
            }

            $index_field = empty($index_field) ? 'DATE' : strtoupper($index_field);

        $fields_a['DATE']         = 1;
            $fields_a['INTERNALDATE'] = 4;
        $fields_a['ARRIVAL']      = 4;
            $fields_a['FROM']         = 1;
        $fields_a['REPLY-TO']     = 1;
            $fields_a['SENDER']       = 1;
        $fields_a['TO']           = 1;
            $fields_a['CC']           = 1;
        $fields_a['SUBJECT']      = 1;
            $fields_a['UID']          = 2;
        $fields_a['SIZE']         = 2;
            $fields_a['SEEN']         = 3;
        $fields_a['RECENT']       = 3;
            $fields_a['DELETED']      = 3;

        if (!($mode = $fields_a[$index_field])) {
                return false;
            }

        /*  Do "SELECT" command */
            if (!$this->select($mailbox)) {
                    return false;
            }

        // build FETCH command string
            $key     = 'fhi0';
            $cmd     = $uidfetch ? 'UID FETCH' : 'FETCH';
            $deleted = $skip_deleted ? ' FLAGS' : '';

            if ($mode == 1 && $index_field == 'DATE')
                    $request = " $cmd $message_set (INTERNALDATE BODY.PEEK[HEADER.FIELDS (DATE)]$deleted)";
            else if ($mode == 1)
                    $request = " $cmd $message_set (BODY.PEEK[HEADER.FIELDS ($index_field)]$deleted)";
            else if ($mode == 2) {
                    if ($index_field == 'SIZE')
                            $request = " $cmd $message_set (RFC822.SIZE$deleted)";
                    else
                            $request = " $cmd $message_set ($index_field$deleted)";
            } else if ($mode == 3)
                    $request = " $cmd $message_set (FLAGS)";
            else // 4
                    $request = " $cmd $message_set (INTERNALDATE$deleted)";

            $request = $key . $request;

            if (!$this->putLine($request)) {
            $this->set_error(self::ERROR_COMMAND, "Unable to send command: $request");
                    return false;
        }

            $result = array();

            do {
                    $line = rtrim($this->readLine(200));
                    $line = $this->multLine($line);

                    if (preg_match('/^\* ([0-9]+) FETCH/', $line, $m)) {
                $id     = $m[1];
                            $flags  = NULL;

                            if ($skip_deleted && preg_match('/FLAGS \(([^)]+)\)/', $line, $matches)) {
                                    $flags = explode(' ', strtoupper($matches[1]));
                                    if (in_array('\\DELETED', $flags)) {
                                            $deleted[$id] = $id;
                                            continue;
                                    }
                            }

                            if ($mode == 1 && $index_field == 'DATE') {
                                    if (preg_match('/BODY\[HEADER\.FIELDS \("*DATE"*\)\] (.*)/', $line, $matches)) {
                                            $value = preg_replace(array('/^"*[a-z]+:/i'), '', $matches[1]);
                                            $value = trim($value);
                                            $result[$id] = $this->strToTime($value);
                                    }
                                    // non-existent/empty Date: header, use INTERNALDATE
                                    if (empty($result[$id])) {
                                            if (preg_match('/INTERNALDATE "([^"]+)"/', $line, $matches))
                                                    $result[$id] = $this->strToTime($matches[1]);
                                            else
                                                    $result[$id] = 0;
                                    }
                            } else if ($mode == 1) {
                                    if (preg_match('/BODY\[HEADER\.FIELDS \("?(FROM|REPLY-TO|SENDER|TO|SUBJECT)"?\)\] (.*)/', $line, $matches)) {
                                            $value = preg_replace(array('/^"*[a-z]+:/i', '/\s+$/sm'), array('', ''), $matches[2]);
                                            $result[$id] = trim($value);
                                    } else {
                                            $result[$id] = '';
                                    }
                            } else if ($mode == 2) {
                                    if (preg_match('/\((UID|RFC822\.SIZE) ([0-9]+)/', $line, $matches)) {
                                            $result[$id] = trim($matches[2]);
                                    } else {
                                            $result[$id] = 0;
                                    }
                            } else if ($mode == 3) {
                                    if (!$flags && preg_match('/FLAGS \(([^)]+)\)/', $line, $matches)) {
                                            $flags = explode(' ', $matches[1]);
                                    }
                                    $result[$id] = in_array('\\'.$index_field, $flags) ? 1 : 0;
                            } else if ($mode == 4) {
                                    if (preg_match('/INTERNALDATE "([^"]+)"/', $line, $matches)) {
                                            $result[$id] = $this->strToTime($matches[1]);
                                    } else {
                                            $result[$id] = 0;
                                    }
                            }
                    }
            } while (!$this->startsWith($line, $key, true, true));

            return $result;
    }

    private function compressMessageSet($message_set)
    {
            // given a comma delimited list of independent mid's,
            // compresses by grouping sequences together

            // if less than 255 bytes long, let's not bother
            if (strlen($message_set)<255) {
                return $message_set;
            }

            // see if it's already been compress
            if (strpos($message_set, ':') !== false) {
                return $message_set;
            }

            // separate, then sort
            $ids = explode(',', $message_set);
            sort($ids);

            $result = array();
            $start  = $prev = $ids[0];

            foreach ($ids as $id) {
                    $incr = $id - $prev;
                    if ($incr > 1) {                    //found a gap
                            if ($start == $prev) {
                                $result[] = $prev;      //push single id
                            } else {
                                $result[] = $start . ':' . $prev;   //push sequence as start_id:end_id
                            }
                        $start = $id;                   //start of new sequence
                    }
                    $prev = $id;
            }

            // handle the last sequence/id
            if ($start==$prev) {
                $result[] = $prev;
            } else {
            $result[] = $start.':'.$prev;
            }

            // return as comma separated string
            return implode(',', $result);
    }

    function UID2ID($folder, $uid)
    {
            if ($uid > 0) {
                $id_a = $this->search($folder, "UID $uid");
                if (is_array($id_a) && count($id_a) == 1) {
                        return $id_a[0];
                    }
            }
            return false;
    }

    function ID2UID($folder, $id)
    {
            if (empty($id)) {
                return  -1;
            }

        if (!$this->select($folder)) {
            return -1;
        }

            $result = -1;
        $command = "fuid FETCH $id (UID)";

                if (!$this->putLine($command)) {
            $this->set_error(self::ERROR_COMMAND, "Unable to send command: $command");
            return -1;
        }

            do {
                    $line = rtrim($this->readLine(1024));
                        if (preg_match("/^\* $id FETCH \(UID (.*)\)/i", $line, $r)) {
                                $result = $r[1];
                        }
                } while (!$this->startsWith($line, 'fuid', true, true));

        return $result;
    }

    function fetchUIDs($mailbox, $message_set=null)
    {
            if (is_array($message_set))
                    $message_set = join(',', $message_set);
        else if (empty($message_set))
                    $message_set = '1:*';

            return $this->fetchHeaderIndex($mailbox, $message_set, 'UID', false);
    }

    function fetchHeaders($mailbox, $message_set, $uidfetch=false, $bodystr=false, $add='')
    {
            $result = array();

            if (!$this->select($mailbox)) {
                    return false;
            }

            if (is_array($message_set))
                    $message_set = join(',', $message_set);

            $message_set = $this->compressMessageSet($message_set);

            if ($add)
                    $add = ' '.trim($add);

            /* FETCH uid, size, flags and headers */
            $key          = 'FH12';
            $request  = $key . ($uidfetch ? ' UID' : '') . " FETCH $message_set ";
            $request .= "(UID RFC822.SIZE FLAGS INTERNALDATE ";
            if ($bodystr)
                    $request .= "BODYSTRUCTURE ";
            $request .= "BODY.PEEK[HEADER.FIELDS (DATE FROM TO SUBJECT CONTENT-TYPE ";
            $request .= "LIST-POST DISPOSITION-NOTIFICATION-TO".$add.")])";

            if (!$this->putLine($request)) {
            $this->set_error(self::ERROR_COMMAND, "Unable to send command: $request");
                    return false;
            }
            do {
                    $line = $this->readLine(1024);
                    $line = $this->multLine($line);

            if (!$line)
                break;

                    if (preg_match('/^\* ([0-9]+) FETCH/', $line, $m)) {
                            $id = intval($m[1]);

                            $result[$id]            = new rcube_mail_header;
                            $result[$id]->id        = $id;
                            $result[$id]->subject   = '';
                            $result[$id]->messageID = 'mid:' . $id;

                            $lines = array();
                            $ln = 0;

                            // Sample reply line:
                            // * 321 FETCH (UID 2417 RFC822.SIZE 2730 FLAGS (\Seen)
                            // INTERNALDATE "16-Nov-2008 21:08:46 +0100" BODYSTRUCTURE (...)
                            // BODY[HEADER.FIELDS ...

                            if (preg_match('/^\* [0-9]+ FETCH \((.*) BODY/s', $line, $matches)) {
                                    $str = $matches[1];

                                    // swap parents with quotes, then explode
                                    $str = preg_replace('/[()]/', '"', $str);
                                    $a = rcube_explode_quoted_string(' ', $str);

                                    // did we get the right number of replies?
                                    $parts_count = count($a);
                                    if ($parts_count>=6) {
                                            for ($i=0; $i<$parts_count; $i=$i+2) {
                                                    if ($a[$i] == 'UID')
                                                            $result[$id]->uid = intval($a[$i+1]);
                                                    else if ($a[$i] == 'RFC822.SIZE')
                                                            $result[$id]->size = intval($a[$i+1]);
                                                else if ($a[$i] == 'INTERNALDATE')
                                                        $time_str = $a[$i+1];
                                                else if ($a[$i] == 'FLAGS')
                                                        $flags_str = $a[$i+1];
                                        }

                                            $time_str = str_replace('"', '', $time_str);

                                            // if time is gmt...
                                $time_str = str_replace('GMT','+0000',$time_str);

                                            $result[$id]->internaldate = $time_str;
                                        $result[$id]->timestamp = $this->StrToTime($time_str);
                                        $result[$id]->date = $time_str;
                                }

                                // BODYSTRUCTURE
                                    if($bodystr) {
                                            while (!preg_match('/ BODYSTRUCTURE (.*) BODY\[HEADER.FIELDS/s', $line, $m)) {
                                                    $line2 = $this->readLine(1024);
                                                $line .= $this->multLine($line2, true);
                                        }
                                        $result[$id]->body_structure = $m[1];
                                }

                                // the rest of the result
                                preg_match('/ BODY\[HEADER.FIELDS \(.*?\)\]\s*(.*)$/s', $line, $m);
                                $reslines = explode("\n", trim($m[1], '"'));
                                // re-parse (see below)
                                    foreach ($reslines as $resln) {
                                        if (ord($resln[0])<=32) {
                                                $lines[$ln] .= (empty($lines[$ln])?'':"\n").trim($resln);
                                        } else {
                                                $lines[++$ln] = trim($resln);
                                            }
                                }
                        }

                                // Start parsing headers.  The problem is, some header "lines" take up multiple lines.
                                // So, we'll read ahead, and if the one we're reading now is a valid header, we'll
                                // process the previous line.  Otherwise, we'll keep adding the strings until we come
                                // to the next valid header line.

                            do {
                                    $line = rtrim($this->readLine(300), "\r\n");

                                // The preg_match below works around communigate imap, which outputs " UID <number>)".
                                // Without this, the while statement continues on and gets the "FH0 OK completed" message.
                                // If this loop gets the ending message, then the outer loop does not receive it from radline on line 1249.
                                // This in causes the if statement on line 1278 to never be true, which causes the headers to end up missing
                                    // If the if statement was changed to pick up the fh0 from this loop, then it causes the outer loop to spin
                                // An alternative might be:
                                // if (!preg_match("/:/",$line) && preg_match("/\)$/",$line)) break;
                                // however, unsure how well this would work with all imap clients.
                                if (preg_match("/^\s*UID [0-9]+\)$/", $line)) {
                                        break;
                                    }

                                // handle FLAGS reply after headers (AOL, Zimbra?)
                                if (preg_match('/\s+FLAGS \((.*)\)\)$/', $line, $matches)) {
                                        $flags_str = $matches[1];
                                        break;
                                    }

                                if (ord($line[0])<=32) {
                                        $lines[$ln] .= (empty($lines[$ln])?'':"\n").trim($line);
                                } else {
                                        $lines[++$ln] = trim($line);
                                    }
                        // patch from "Maksim Rubis" <siburny@hotmail.com>
                        } while ($line[0] != ')' && !$this->startsWith($line, $key, true));

                        if (strncmp($line, $key, strlen($key))) {
                                // process header, fill rcube_mail_header obj.
                                // initialize
                                if (is_array($headers)) {
                                        reset($headers);
                                            while (list($k, $bar) = each($headers)) {
                                                $headers[$k] = '';
                                        }
                                }

                                // create array with header field:data
                                while ( list($lines_key, $str) = each($lines) ) {
                                        list($field, $string) = $this->splitHeaderLine($str);

                                        $field  = strtolower($field);
                                        $string = preg_replace('/\n\s*/', ' ', $string);

                                        switch ($field) {
                                        case 'date';
                                                $result[$id]->date = $string;
                                                $result[$id]->timestamp = $this->strToTime($string);
                                        break;
                                        case 'from':
                                                $result[$id]->from = $string;
                                                break;
                                        case 'to':
                                                $result[$id]->to = preg_replace('/undisclosed-recipients:[;,]*/', '', $string);
                                                break;
                                        case 'subject':
                                                $result[$id]->subject = $string;
                                                break;
                                        case 'reply-to':
                                                $result[$id]->replyto = $string;
                                                break;
                                        case 'cc':
                                                $result[$id]->cc = $string;
                                                break;
                                        case 'bcc':
                                                $result[$id]->bcc = $string;
                                                break;
                                        case 'content-transfer-encoding':
                                                $result[$id]->encoding = $string;
                                                break;
                                        case 'content-type':
                                                $ctype_parts = preg_split('/[; ]/', $string);
                                                $result[$id]->ctype = array_shift($ctype_parts);
                                                if (preg_match('/charset\s*=\s*"?([a-z0-9\-\.\_]+)"?/i', $string, $regs)) {
                                                        $result[$id]->charset = $regs[1];
                                                }
                                                break;
                                            case 'in-reply-to':
                                                $result[$id]->in_reply_to = str_replace(array("\n", '<', '>'), '', $string);
                                                break;
                                        case 'references':
                                                $result[$id]->references = $string;
                                                break;
                                        case 'return-receipt-to':
                                        case 'disposition-notification-to':
                                            case 'x-confirm-reading-to':
                                                $result[$id]->mdn_to = $string;
                                                break;
                                        case 'message-id':
                                                $result[$id]->messageID = $string;
                                                break;
                                            case 'x-priority':
                                                if (preg_match('/^(\d+)/', $string, $matches))
                                                        $result[$id]->priority = intval($matches[1]);
                                                break;
                                        default:
                                                if (strlen($field) > 2)
                                                        $result[$id]->others[$field] = $string;
                                                    break;
                                        } // end switch ()
                                } // end while ()
                            }

                        // process flags
                        if (!empty($flags_str)) {
                                $flags_str = preg_replace('/[\\\"]/', '', $flags_str);
                                $flags_a   = explode(' ', $flags_str);

                                    if (is_array($flags_a)) {
                                        foreach($flags_a as $flag) {
                                                $flag = strtoupper($flag);
                                                if ($flag == 'SEEN') {
                                                    $result[$id]->seen = true;
                                                } else if ($flag == 'DELETED') {
                                                    $result[$id]->deleted = true;
                                                } else if ($flag == 'RECENT') {
                                                    $result[$id]->recent = true;
                                                } else if ($flag == 'ANSWERED') {
                                                        $result[$id]->answered = true;
                                                } else if ($flag == '$FORWARDED') {
                                                        $result[$id]->forwarded = true;
                                                } else if ($flag == 'DRAFT') {
                                                        $result[$id]->is_draft = true;
                                                } else if ($flag == '$MDNSENT') {
                                                        $result[$id]->mdn_sent = true;
                                                } else if ($flag == 'FLAGGED') {
                                                         $result[$id]->flagged = true;
                                                    }
                                        }
                                        $result[$id]->flags = $flags_a;
                                }
                            }
                }
            } while (!$this->startsWith($line, $key, true));

        return $result;
    }

    function fetchHeader($mailbox, $id, $uidfetch=false, $bodystr=false, $add='')
    {
            $a  = $this->fetchHeaders($mailbox, $id, $uidfetch, $bodystr, $add);
            if (is_array($a)) {
                    return array_shift($a);
            }
            return false;
    }

    function sortHeaders($a, $field, $flag)
    {
            if (empty($field)) {
                $field = 'uid';
            }
        else {
            $field = strtolower($field);
        }

            if ($field == 'date' || $field == 'internaldate') {
                $field = 'timestamp';
            }
        if (empty($flag)) {
                $flag = 'ASC';
            } else {
                $flag = strtoupper($flag);
        }

            $stripArr = ($field=='subject') ? array('Re: ','Fwd: ','Fw: ','"') : array('"');

            $c = count($a);
            if ($c > 0) {

                        // Strategy:
                        // First, we'll create an "index" array.
                        // Then, we'll use sort() on that array,
                        // and use that to sort the main array.

                    // create "index" array
                    $index = array();
                    reset($a);
                    while (list($key, $val) = each($a)) {
                            if ($field == 'timestamp') {
                                    $data = $this->strToTime($val->date);
                                    if (!$data) {
                                            $data = $val->timestamp;
                        }
                            } else {
                                    $data = $val->$field;
                                    if (is_string($data)) {
                                            $data = strtoupper(str_replace($stripArr, '', $data));
                        }
                            }
                        $index[$key]=$data;
                }

                    // sort index
                $i = 0;
                if ($flag == 'ASC') {
                        asort($index);
                } else {
                    arsort($index);
                    }

                // form new array based on index
                $result = array();
                    reset($index);
                while (list($key, $val) = each($index)) {
                        $result[$key]=$a[$key];
                        $i++;
                    }
            }

            return $result;
    }

    function expunge($mailbox, $messages=NULL)
    {
            if (!$this->select($mailbox)) {
            return -1;
        }

        $c = 0;
                $command = $messages ? "exp1 UID EXPUNGE $messages" : "exp1 EXPUNGE";

                if (!$this->putLine($command)) {
            $this->set_error(self::ERROR_COMMAND, "Unable to send command: $command");
            return -1;
        }

                do {
                        $line = $this->readLine(100);
                        if ($line[0] == '*') {
                $c++;
                }
                } while (!$this->startsWith($line, 'exp1', true, true));

                if ($this->parseResult($line, 'EXPUNGE: ') == self::ERROR_OK) {
                        $this->selected = ''; // state has changed, need to reselect
                        return $c;
                }

            return -1;
    }

    function modFlag($mailbox, $messages, $flag, $mod)
    {
            if ($mod != '+' && $mod != '-') {
                return -1;
            }

            $flag = $this->flags[strtoupper($flag)];

            if (!$this->select($mailbox)) {
                return -1;
            }

        $c = 0;
        $command = "flg UID STORE $messages {$mod}FLAGS ($flag)";
            if (!$this->putLine($command)) {
            $this->set_error(self::ERROR_COMMAND, "Unable to send command: $command");
            return false;
        }

            do {
                    $line = $this->readLine();
                    if ($line[0] == '*') {
                        $c++;
            }
            } while (!$this->startsWith($line, 'flg', true, true));

            if ($this->parseResult($line, 'STORE: ') == self::ERROR_OK) {
                    return $c;
            }

            return -1;
    }

    function flag($mailbox, $messages, $flag) {
            return $this->modFlag($mailbox, $messages, $flag, '+');
    }

    function unflag($mailbox, $messages, $flag) {
            return $this->modFlag($mailbox, $messages, $flag, '-');
    }

    function delete($mailbox, $messages) {
            return $this->modFlag($mailbox, $messages, 'DELETED', '+');
    }

    function copy($messages, $from, $to)
    {
            if (empty($from) || empty($to)) {
                return -1;
            }

            if (!$this->select($from)) {
            return -1;
            }

        $command = "cpy1 UID COPY $messages \"".$this->escape($to)."\"";

        if (!$this->putLine($command)) {
            $this->set_error(self::ERROR_COMMAND, "Unable to send command: $command");
        }

        $line = $this->readReply();
            return $this->parseResult($line, 'COPY: ');
    }

    function countUnseen($folder)
    {
        $index = $this->search($folder, 'ALL UNSEEN');
        if (is_array($index))
            return count($index);
        return false;
    }

    // Don't be tempted to change $str to pass by reference to speed this up - it will slow it down by about
    // 7 times instead :-) See comments on http://uk2.php.net/references and this article:
    // http://derickrethans.nl/files/phparch-php-variables-article.pdf
    private function parseThread($str, $begin, $end, $root, $parent, $depth, &$depthmap, &$haschildren)
    {
            $node = array();
            if ($str[$begin] != '(') {
                    $stop = $begin + strspn($str, '1234567890', $begin, $end - $begin);
                    $msg = substr($str, $begin, $stop - $begin);
                    if ($msg == 0)
                        return $node;
                    if (is_null($root))
                            $root = $msg;
                    $depthmap[$msg] = $depth;
                    $haschildren[$msg] = false;
                    if (!is_null($parent))
                            $haschildren[$parent] = true;
                    if ($stop + 1 < $end)
                            $node[$msg] = $this->parseThread($str, $stop + 1, $end, $root, $msg, $depth + 1, $depthmap, $haschildren);
                    else
                            $node[$msg] = array();
            } else {
                    $off = $begin;
                    while ($off < $end) {
                            $start = $off;
                        $off++;
                        $n = 1;
                        while ($n > 0) {
                                $p = strpos($str, ')', $off);
                                    if ($p === false) {
                                            error_log('Mismatched brackets parsing IMAP THREAD response:');
                                        error_log(substr($str, ($begin < 10) ? 0 : ($begin - 10), $end - $begin + 20));
                                        error_log(str_repeat(' ', $off - (($begin < 10) ? 0 : ($begin - 10))));
                                        return $node;
                                }
                                    $p1 = strpos($str, '(', $off);
                                if ($p1 !== false && $p1 < $p) {
                                        $off = $p1 + 1;
                                        $n++;
                                } else {
                                        $off = $p + 1;
                                            $n--;
                                }
                        }
                        $node += $this->parseThread($str, $start + 1, $off - 1, $root, $parent, $depth, $depthmap, $haschildren);
                    }
            }

            return $node;
    }

    function thread($folder, $algorithm='REFERENCES', $criteria='', $encoding='US-ASCII')
    {
        $old_sel = $this->selected;

            if (!$this->select($folder)) {
                return false;
            }

        // return empty result when folder is empty and we're just after SELECT
        if ($old_sel != $folder && !$this->exists) {
            return array(array(), array(), array());
            }

        $encoding  = $encoding ? trim($encoding) : 'US-ASCII';
            $algorithm = $algorithm ? trim($algorithm) : 'REFERENCES';
            $criteria  = $criteria ? 'ALL '.trim($criteria) : 'ALL';
        $data      = '';

        $command = "thrd1 THREAD $algorithm $encoding $criteria";

            if (!$this->putLineC($command)) {
            $this->set_error(self::ERROR_COMMAND, "Unable to send command: $command");
                    return false;
            }
            do {
                    $line = trim($this->readLine());
                    if (!$data && preg_match('/^\* THREAD/', $line)) {
                        $data .= substr($line, 9);
                } else if (preg_match('/^[0-9() ]+$/', $line)) {
                        $data .= $line;
                    }
            } while (!$this->startsWith($line, 'thrd1', true, true));

        $result_code = $this->parseResult($line, 'THREAD: ');
            if ($result_code == self::ERROR_OK) {
            $depthmap    = array();
            $haschildren = array();
            $tree = $this->parseThread($data, 0, strlen($data), null, null, 0, $depthmap, $haschildren);
            return array($tree, $depthmap, $haschildren);
            }

            return false;
    }

    function search($folder, $criteria, $return_uid=false)
    {
        $old_sel = $this->selected;

            if (!$this->select($folder)) {
                return false;
            }

        // return empty result when folder is empty and we're just after SELECT
        if ($old_sel != $folder && !$this->exists) {
            return array();
            }

        $data = '';
            $query = 'srch1 ' . ($return_uid ? 'UID ' : '') . 'SEARCH ' . trim($criteria);

            if (!$this->putLineC($query)) {
            $this->set_error(self::ERROR_COMMAND, "Unable to send command: $query");
                    return false;
            }

        do {
                $line = trim($this->readLine());
                    if (!$data && preg_match('/^\* SEARCH/', $line)) {
                        $data .= substr($line, 8);
                } else if (preg_match('/^[0-9 ]+$/', $line)) {
                        $data .= $line;
                    }
        } while (!$this->startsWith($line, 'srch1', true, true));

            $result_code = $this->parseResult($line, 'SEARCH: ');
            if ($result_code == self::ERROR_OK) {
                    return preg_split('/\s+/', $data, -1, PREG_SPLIT_NO_EMPTY);
            }

            return false;
    }

    function move($messages, $from, $to)
    {
        if (!$from || !$to) {
            return -1;
        }

        $r = $this->copy($messages, $from, $to);

        if ($r==0) {
            return $this->delete($from, $messages);
        }
        return $r;
    }

    function listMailboxes($ref, $mailbox)
    {
        return $this->_listMailboxes($ref, $mailbox, false);
    }

    function listSubscribed($ref, $mailbox)
    {
        return $this->_listMailboxes($ref, $mailbox, true);
    }

    private function _listMailboxes($ref, $mailbox, $subscribed=false)
    {
                if (empty($mailbox)) {
                $mailbox = '*';
            }

            if (empty($ref) && $this->rootdir) {
                $ref = $this->rootdir;
            }

        if ($subscribed) {
            $key     = 'lsb';
            $command = 'LSUB';
        }
        else {
            $key     = 'lmb';
            $command = 'LIST';
        }

        $ref = $this->escape($ref);
        $mailbox = $this->escape($mailbox);
        $query = $key." ".$command." \"". $ref ."\" \"". $mailbox ."\"";

        // send command
            if (!$this->putLine($query)) {
            $this->set_error(self::ERROR_COMMAND, "Unable to send command: $query");
                return false;
            }

            // get folder list
            do {
                    $line = $this->readLine(500);
                    $line = $this->multLine($line, true);
                    $line = trim($line);

                    if (preg_match('/^\* '.$command.' \(([^\)]*)\) "*([^"]+)"* (.*)$/', $line, $m)) {
                        // folder name
                            $folders[] = preg_replace(array('/^"/', '/"$/'), '', $this->unEscape($m[3]));
                        // attributes
//                      $attrib = explode(' ', $this->unEscape($m[1]));
                        // delimiter
//                      $delim = $this->unEscape($m[2]);
                    }
            } while (!$this->startsWith($line, $key, true));

            if (is_array($folders)) {
            return $folders;
            } else if ($this->parseResult($line, $command.': ') == self::ERROR_OK) {
            return array();
        }

        return false;
    }

    function fetchMIMEHeaders($mailbox, $id, $parts, $mime=true)
    {
            if (!$this->select($mailbox)) {
                    return false;
            }

        $result = false;
            $parts  = (array) $parts;
        $key    = 'fmh0';
            $peeks  = '';
        $idx    = 0;
        $type   = $mime ? 'MIME' : 'HEADER';

            // format request
            foreach($parts as $part)
                    $peeks[] = "BODY.PEEK[$part.$type]";

            $request = "$key FETCH $id (" . implode(' ', $peeks) . ')';

            // send request
            if (!$this->putLine($request)) {
            $this->set_error(self::ERROR_COMMAND, "Unable to send command: $request");
                return false;
            }

            do {
                $line = $this->readLine(1024);
                $line = $this->multLine($line);

                    if (preg_match('/BODY\[([0-9\.]+)\.'.$type.'\]/', $line, $matches)) {
                            $idx = $matches[1];
                        $result[$idx] = preg_replace('/^(\* '.$id.' FETCH \()?\s*BODY\['.$idx.'\.'.$type.'\]\s+/', '', $line);
                        $result[$idx] = trim($result[$idx], '"');
                        $result[$idx] = rtrim($result[$idx], "\t\r\n\0\x0B");
                }
            } while (!$this->startsWith($line, $key, true));

            return $result;
    }

    function fetchPartHeader($mailbox, $id, $is_uid=false, $part=NULL)
    {
            $part = empty($part) ? 'HEADER' : $part.'.MIME';

        return $this->handlePartBody($mailbox, $id, $is_uid, $part);
    }

    function handlePartBody($mailbox, $id, $is_uid=false, $part='', $encoding=NULL, $print=NULL, $file=NULL)
    {
        if (!$this->select($mailbox)) {
            return false;
        }

            switch ($encoding) {
                    case 'base64':
                            $mode = 1;
                break;
                case 'quoted-printable':
                        $mode = 2;
                break;
                case 'x-uuencode':
                    case 'x-uue':
                case 'uue':
                case 'uuencode':
                        $mode = 3;
                break;
                default:
                        $mode = 0;
            }

        // format request
                $reply_key = '* ' . $id;
                $key       = 'ftch0';
                $request   = $key . ($is_uid ? ' UID' : '') . " FETCH $id (BODY.PEEK[$part])";

        // send request
                if (!$this->putLine($request)) {
            $this->set_error(self::ERROR_COMMAND, "Unable to send command: $request");
                    return false;
                }

                // receive reply line
                do {
                $line = rtrim($this->readLine(1024));
                $a    = explode(' ', $line);
                } while (!($end = $this->startsWith($line, $key, true)) && $a[2] != 'FETCH');

                $len    = strlen($line);
        $result = false;

                // handle empty "* X FETCH ()" response
        if ($line[$len-1] == ')' && $line[$len-2] != '(') {
                // one line response, get everything between first and last quotes
                        if (substr($line, -4, 3) == 'NIL') {
                                // NIL response
                                $result = '';
                        } else {
                            $from = strpos($line, '"') + 1;
                        $to   = strrpos($line, '"');
                        $len  = $to - $from;
                                $result = substr($line, $from, $len);
                        }

                if ($mode == 1)
                                $result = base64_decode($result);
                        else if ($mode == 2)
                                $result = quoted_printable_decode($result);
                        else if ($mode == 3)
                                $result = convert_uudecode($result);

        } else if ($line[$len-1] == '}') {
                // multi-line request, find sizes of content and receive that many bytes
                $from     = strpos($line, '{') + 1;
                $to       = strrpos($line, '}');
                $len      = $to - $from;
                $sizeStr  = substr($line, $from, $len);
                $bytes    = (int)$sizeStr;
                        $prev     = '';

                while ($bytes > 0) {
                    $line = $this->readLine(1024);

                    if ($line === NULL)
                        break;

                $len  = strlen($line);

                        if ($len > $bytes) {
                        $line = substr($line, 0, $bytes);
                                        $len = strlen($line);
                        }
                $bytes -= $len;

                        if ($mode == 1) {
                                        $line = rtrim($line, "\t\r\n\0\x0B");
                                        // create chunks with proper length for base64 decoding
                                        $line = $prev.$line;
                                        $length = strlen($line);
                                        if ($length % 4) {
                                                $length = floor($length / 4) * 4;
                                                $prev = substr($line, $length);
                                                $line = substr($line, 0, $length);
                                        }
                                        else
                                                $prev = '';

                                        if ($file)
                                                fwrite($file, base64_decode($line));
                        else if ($print)
                                                echo base64_decode($line);
                                        else
                                                $result .= base64_decode($line);
                                } else if ($mode == 2) {
                                        $line = rtrim($line, "\t\r\0\x0B");
                                        if ($file)
                                                fwrite($file, quoted_printable_decode($line));
                        else if ($print)
                                                echo quoted_printable_decode($line);
                                        else
                                                $result .= quoted_printable_decode($line);
                                } else if ($mode == 3) {
                                        $line = rtrim($line, "\t\r\n\0\x0B");
                                        if ($line == 'end' || preg_match('/^begin\s+[0-7]+\s+.+$/', $line))
                                                continue;
                                        if ($file)
                                                fwrite($file, convert_uudecode($line));
                        else if ($print)
                                                echo convert_uudecode($line);
                                        else
                                                $result .= convert_uudecode($line);
                                } else {
                                        $line = rtrim($line, "\t\r\n\0\x0B");
                                        if ($file)
                                                fwrite($file, $line . "\n");
                        else if ($print)
                                                echo $line . "\n";
                                        else
                                                $result .= $line . "\n";
                                }
                }
        }

        // read in anything up until last line
                if (!$end)
                        do {
                                $line = $this->readLine(1024);
                        } while (!$this->startsWith($line, $key, true));

                if ($result !== false) {
                if ($file) {
                        fwrite($file, $result);
                        } else if ($print) {
                        echo $result;
                } else
                        return $result;
                        return true;
                }

            return false;
    }

    function createFolder($folder)
    {
        $command = 'c CREATE "' . $this->escape($folder) . '"';
    
            if (!$this->putLine($command)) {
            $this->set_error(self::ERROR_COMMAND, "Unable to send command: $command");
            return false;
        }

            do {
                    $line = $this->readLine(300);
            } while (!$this->startsWith($line, 'c ', true, true));

            return ($this->parseResult($line, 'CREATE: ') == self::ERROR_OK);
    }

    function renameFolder($from, $to)
    {
        $command = 'r RENAME "' . $this->escape($from) . '" "' . $this->escape($to) . '"';
    
            if (!$this->putLine($command)) {
            $this->set_error(self::ERROR_COMMAND, "Unable to send command: $command");
            return false;
        }
                do {
                    $line = $this->readLine(300);
                } while (!$this->startsWith($line, 'r ', true, true));

                return ($this->parseResult($line, 'RENAME: ') == self::ERROR_OK);
    }

    function deleteFolder($folder)
    {
        $command = 'd DELETE "' . $this->escape($folder). '"';
    
            if (!$this->putLine($command)) {
            $this->set_error(self::ERROR_COMMAND, "Unable to send command: $command");
            return false;
        }
            do {
                    $line = $this->readLine(300);
            } while (!$this->startsWith($line, 'd ', true, true));

            return ($this->parseResult($line, 'DELETE: ') == self::ERROR_OK);
    }

    function clearFolder($folder)
    {
            $num_in_trash = $this->countMessages($folder);
            if ($num_in_trash > 0) {
                    $this->delete($folder, '1:*');
            }
            return ($this->expunge($folder) >= 0);
    }

    function subscribe($folder)
    {
            $command = 'sub1 SUBSCRIBE "' . $this->escape($folder). '"';

            if (!$this->putLine($command)) {
            $this->set_error(self::ERROR_COMMAND, "Unable to send command: $command");
            return false;
        }

        $line = trim($this->readLine(512));
            return ($this->parseResult($line, 'SUBSCRIBE: ') == self::ERROR_OK);
    }

    function unsubscribe($folder)
    {
        $command = 'usub1 UNSUBSCRIBE "' . $this->escape($folder) . '"';

            if (!$this->putLine($command)) {
            $this->set_error(self::ERROR_COMMAND, "Unable to send command: $command");
            return false;
        }

            $line = trim($this->readLine(512));
            return ($this->parseResult($line, 'UNSUBSCRIBE: ') == self::ERROR_OK);
    }

    function append($folder, &$message)
    {
            if (!$folder) {
                    return false;
            }

        $message = str_replace("\r", '', $message);
            $message = str_replace("\n", "\r\n", $message);

        $len = strlen($message);
            if (!$len) {
                    return false;
            }

            $request = 'a APPEND "' . $this->escape($folder) .'" (\\Seen) {' . $len . '}';

            if ($this->putLine($request)) {
                    $line = $this->readLine(512);

                if ($line[0] != '+') {
                        $this->parseResult($line, 'APPEND: ');
                            return false;
                }

                if (!$this->putLine($message)) {
                return false;
            }

                    do {
                            $line = $this->readLine();
                } while (!$this->startsWith($line, 'a ', true, true));

                return ($this->parseResult($line, 'APPEND: ') == self::ERROR_OK);
            }
        else {
            $this->set_error(self::ERROR_COMMAND, "Unable to send command: $request");
        }

            return false;
    }

    function appendFromFile($folder, $path, $headers=null)
    {
            if (!$folder) {
                return false;
            }

            // open message file
            $in_fp = false;
            if (file_exists(realpath($path))) {
                    $in_fp = fopen($path, 'r');
            }
            if (!$in_fp) {
                    $this->set_error(self::ERROR_UNKNOWN, "Couldn't open $path for reading");
                    return false;
            }

        $body_separator = "\r\n\r\n";
            $len = filesize($path);

            if (!$len) {
                    return false;
            }

        if ($headers) {
            $headers = preg_replace('/[\r\n]+$/', '', $headers);
            $len += strlen($headers) + strlen($body_separator);
        }

        // send APPEND command
            $request    = 'a APPEND "' . $this->escape($folder) . '" (\\Seen) {' . $len . '}';
            if ($this->putLine($request)) {
                    $line = $this->readLine(512);

                    if ($line[0] != '+') {
                            $this->parseResult($line, 'APPEND: ');
                            return false;
                    }

            // send headers with body separator
            if ($headers) {
                            $this->putLine($headers . $body_separator, false);
            }

                    // send file
                    while (!feof($in_fp) && $this->fp) {
                            $buffer = fgets($in_fp, 4096);
                            $this->putLine($buffer, false);
                    }
                    fclose($in_fp);

                    if (!$this->putLine('')) { // \r\n
                return false;
            }

                    // read response
                    do {
                            $line = $this->readLine();
                    } while (!$this->startsWith($line, 'a ', true, true));

                    
                    return ($this->parseResult($line, 'APPEND: ') == self::ERROR_OK);
            }
        else {
            $this->set_error(self::ERROR_COMMAND, "Unable to send command: $request");
        }

            return false;
    }

    function fetchStructureString($folder, $id, $is_uid=false)
    {
            if (!$this->select($folder)) {
            return false;
        }

                $key = 'F1247';
        $result = false;
        $command = $key . ($is_uid ? ' UID' : '') ." FETCH $id (BODYSTRUCTURE)";

                if ($this->putLine($command)) {
                        do {
                                $line = $this->readLine(5000);
                                $line = $this->multLine($line, true);
                                if (!preg_match("/^$key/", $line))
                                        $result .= $line;
                        } while (!$this->startsWith($line, $key, true, true));

                        $result = trim(substr($result, strpos($result, 'BODYSTRUCTURE')+13, -1));
                }
        else {
            $this->set_error(self::ERROR_COMMAND, "Unable to send command: $command");
        }

        return $result;
    }

    function getQuota()
    {
        /*
         * GETQUOTAROOT "INBOX"
         * QUOTAROOT INBOX user/rchijiiwa1
         * QUOTA user/rchijiiwa1 (STORAGE 654 9765)
         * OK Completed
         */
            $result      = false;
            $quota_lines = array();
        $command     = 'QUOT1 GETQUOTAROOT "INBOX"';

            // get line(s) containing quota info
            if ($this->putLine($command)) {
                    do {
                            $line = rtrim($this->readLine(5000));
                            if (preg_match('/^\* QUOTA /', $line)) {
                                    $quota_lines[] = $line;
                        }
                    } while (!$this->startsWith($line, 'QUOT1', true, true));
            }
        else {
            $this->set_error(self::ERROR_COMMAND, "Unable to send command: $command");
        }

            // return false if not found, parse if found
            $min_free = PHP_INT_MAX;
            foreach ($quota_lines as $key => $quota_line) {
                    $quota_line   = str_replace(array('(', ')'), '', $quota_line);
                    $parts        = explode(' ', $quota_line);
                    $storage_part = array_search('STORAGE', $parts);

                    if (!$storage_part)
                continue;

                    $used  = intval($parts[$storage_part+1]);
                    $total = intval($parts[$storage_part+2]);
                    $free  = $total - $used;

                    // return lowest available space from all quotas
                    if ($free < $min_free) {
                        $min_free          = $free;
                            $result['used']    = $used;
                            $result['total']   = $total;
                            $result['percent'] = min(100, round(($used/max(1,$total))*100));
                            $result['free']    = 100 - $result['percent'];
                    }
            }

            return $result;
    }

    private function _xor($string, $string2)
    {
            $result = '';
            $size = strlen($string);
            for ($i=0; $i<$size; $i++) {
                $result .= chr(ord($string[$i]) ^ ord($string2[$i]));
            }
            return $result;
    }

    private function strToTime($date)
    {
            // support non-standard "GMTXXXX" literal
            $date = preg_replace('/GMT\s*([+-][0-9]+)/', '\\1', $date);
        // if date parsing fails, we have a date in non-rfc format.
            // remove token from the end and try again
            while ((($ts = @strtotime($date))===false) || ($ts < 0)) {
                $d = explode(' ', $date);
                    array_pop($d);
                    if (!$d) break;
                    $date = implode(' ', $d);
            }

            $ts = (int) $ts;

            return $ts < 0 ? 0 : $ts;
    }

    private function SplitHeaderLine($string)
    {
            $pos = strpos($string, ':');
            if ($pos>0) {
                    $res[0] = substr($string, 0, $pos);
                    $res[1] = trim(substr($string, $pos+1));
                    return $res;
            }
        return $string;
    }

    private function parseNamespace($str, &$i, $len=0, $l)
    {
            if (!$l) {
                $str = str_replace('NIL', '()', $str);
            }
            if (!$len) {
                $len = strlen($str);
            }
            $data      = array();
            $in_quotes = false;
            $elem      = 0;

        for ($i; $i<$len; $i++) {
                    $c = (string)$str[$i];
                    if ($c == '(' && !$in_quotes) {
                            $i++;
                            $data[$elem] = $this->parseNamespace($str, $i, $len, $l++);
                            $elem++;
                    } else if ($c == ')' && !$in_quotes) {
                            return $data;
                } else if ($c == '\\') {
                            $i++;
                            if ($in_quotes) {
                                    $data[$elem] .= $str[$i];
                        }
                    } else if ($c == '"') {
                            $in_quotes = !$in_quotes;
                            if (!$in_quotes) {
                                    $elem++;
                        }
                    } else if ($in_quotes) {
                            $data[$elem].=$c;
                    }
            }

        return $data;
    }

    private function escape($string)
    {
            return strtr($string, array('"'=>'\\"', '\\' => '\\\\'));
    }

    private function unEscape($string)
    {
            return strtr($string, array('\\"'=>'"', '\\\\' => '\\'));
    }

}