<?php
/*
 * MemCached PHP client
 * Copyright (c) 2003
 * Ryan Gilfether <hotrodder@rocketmail.com>
 * http://www.gilfether.com
 *
 * Originally translated from Brad Fitzpatrick's <brad@danga.com> MemCached Perl client
 * See the memcached website:
 * http://www.danga.com/memcached/
 *
 * This module is Copyright (c) 2003 Ryan Gilfether.
 * All rights reserved.
 * You may distribute under the terms of the GNU General Public License
 * This is free software. IT COMES WITHOUT WARRANTY OF ANY KIND.
 *
 */

/**
 * version string
 */
define("MC_VERSION", "1.0.10");
/**
 * int, buffer size used for sending and receiving
 * data from sockets
 */
define("MC_BUFFER_SZ", 1024);
/**
 * MemCached error numbers
 */
define("MC_ERR_NOT_ACTIVE", 1001);        // no active servers
define("MC_ERR_SOCKET_WRITE", 1002);        // socket_write() failed
define("MC_ERR_SOCKET_READ", 1003);        // socket_read() failed
define("MC_ERR_SOCKET_CONNECT", 1004);        // failed to connect to host
define("MC_ERR_DELETE", 1005);                // delete() did not recieve DELETED command
define("MC_ERR_HOST_FORMAT", 1006);        // sock_to_host() invalid host format
define("MC_ERR_HOST_DEAD", 1007);        // sock_to_host() host is dead
define("MC_ERR_GET_SOCK", 1008);        // get_sock() failed to find a valid socket
define("MC_ERR_SET", 1009);                // _set() failed to receive the STORED response
define("MC_ERR_GET_KEY", 1010);                // _load_items no values returned for key(s)
define("MC_ERR_LOADITEM_END", 1011);        // _load_items failed to receive END response
define("MC_ERR_LOADITEM_BYTES", 1012);        // _load_items bytes read larger than bytes available


/**
 * MemCached PHP client Class.
 *
 * Communicates with the MemCached server, and executes the MemCached protocol
 * MemCached available at http://www.danga.com/memcached
 *
 * @author Ryan Gilfether <ryan@gilfether.com>
 * @package MemCachedClient
 * @access public
 * @version 1.0.10
 */
class MemCachedClient
{
    /**
     * array of servers no long available
     * @var array
     */
    var $host_dead;
    /**
     * array of open sockets
     * @var array
     */
    var $cache_sock;
    /**
     * determine if debugging is either on or off
     * @var bool
     */
    var $debug;
    /**
     * array of servers to attempt to use, "host:port" string format
     * @var array
     */
    var $servers;
    /**
     * count of currently active connections to servers
     * @var int
     */
    var $active;
    /**
     * error code if one is set
     * @var int
     */
    var $errno;
    /**
     * string describing error
     * @var string
     */
    var $errstr;
    /**
     * size of val to force compression; 0 turns off; defaults 1
     * @ var int
     */
    var $compress = 1;
    /**
     * temp flag to turn compression on/off; defaults on
     * @ var int
     */
    var $comp_active = 1;

    /**
     * array that contains parsed out buckets
     * @ var array
     */
    var $bucket;


    /**
     * Constructor
     *
     * Creates a new MemCachedClient object
         * Takes one parameter, a array of options.  The most important key is
         * $options["servers"], but that can also be set later with the set_servers()
         * method.  The servers must be an array of hosts, each of which is
         * either a scalar of the form <10.0.0.10:11211> or an array of the
         * former and an integer weight value.  (the default weight if
         * unspecified is 1.)  It's recommended that weight values be kept as low
         * as possible, as this module currently allocates memory for bucket
         * distribution proportional to the total host weights.
         * $options["debug"] turns the debugging on if set to true
     *
     * @access public
     * @param array $option an array of servers and debug status
     * @return object MemCachedClient the new MemCachedClient object
     */
        function MemCachedClient($options = 0)
        {
                if(is_array($options))
                {
                        $this->set_servers($options["servers"]);
                        $this->debug = $options["debug"];
                        $this->compress = $options["compress"];
                        $this->cache_sock = array();
                }

                $this->errno = 0;
                $this->errstr = "";
        }


        /**
         * sets up the list of servers and the ports to connect to
         * takes an array of servers in the same format as in the constructor
         *
         * @access public
         * @param array $servers array of servers in the format described in the constructor
         */
        function set_servers($servers)
        {
                $this->servers = $servers;
                $this->active = count($this->servers);
        }


        /**
         * if $do_debug is set to true, will print out
         * debugging info, else debug is turned off
         *
         * @access public
         * @param bool $do_debug set to true to turn debugging on, false to turn off
         */
        function set_debug($do_debug)
        {
                $this->debug = $do_debug;
        }


        /**
         * remove all cached hosts that are no longer good
         *
         * @access public
         */
        function forget_dead_hosts()
        {
                unset($this->host_dead);
        }


        /**
         * disconnects from all servers
         *
         * @access public
         */
        function disconnect_all()
        {
                foreach($this->cache_sock as $sock)
                        socket_close($sock);

                unset($this->cache_sock);
                $this->active = 0;
        }


        /**
         * removes the key from the MemCache
         * $time is the amount of time in seconds (or Unix time) until which
         * the client wishes the server to refuse "add" and "replace" commands
         * with this key. For this amount of item, the item is put into a
         * delete queue, which means that it won't possible to retrieve it by
         * the "get" command, but "add" and "replace" command with this key
         * will also fail (the "set" command will succeed, however). After the
         * time passes, the item is finally deleted from server memory.
         * The parameter $time is optional, and, if absent, defaults to 0
         * (which means that the item will be deleted immediately and further
         * storage commands with this key will succeed).
         * Possible errors set are:
         *                MC_ERR_NOT_ACTIVE
         *                MC_ERR_GET_SOCK
         *                MC_ERR_SOCKET_WRITE
         *                MC_ERR_SOCKET_READ
         *                MC_ERR_DELETE
         *
         * @access public
         * @param string $key the key to delete
         * @param timestamp $time optional, the amount of time server will refuse commands on key
         * @return bool TRUE on success, FALSE if key does not exist
         */
        function delete($key, $time = 0)
        {
                if(!$this->active)
                {
                        $this->errno = MC_ERR_NOT_ACTIVE;
                        $this->errstr = "No active servers are available";

                        if($this->debug)
                                $this->_debug("delete(): There are no active servers available.");

                        return FALSE;
                }

                $sock = $this->get_sock($key);

                if(!is_resource($sock))
                {
                        $this->errno = MC_ERR_GET_SOCK;
                        $this->errstr = "Unable to retrieve a valid socket.";

                        if($this->debug)
                                $this->_debug("delete(): get_sock() returned an invalid socket.");

                        return FALSE;
                }

                if(is_array($key))
                        $key = $key[1];

                $cmd = "delete $key $time\r\n";
                $cmd_len = strlen($cmd);
                $offset = 0;

                // now send the command
                while($offset < $cmd_len)
                {
                        $result = socket_write($sock, substr($cmd, $offset, MC_BUFFER_SZ), MC_BUFFER_SZ);

                        if($result !== FALSE)
                                $offset += $result;
                        else if($offset < $cmd_len)
                        {
                                $this->errno = MC_ERR_SOCKET_WRITE;
                                $this->errstr = "Failed to write to socket.";

                                if($this->debug)
                                {
                                        $sockerr = socket_last_error($sock);
                                        $this->_debug("delete(): socket_write() returned FALSE. Socket Error $sockerr: ".socket_strerror($sockerr));
                                }

                                return FALSE;
                        }
                }

                // now read the server's response
                if(($retval = socket_read($sock, MC_BUFFER_SZ, PHP_NORMAL_READ)) === FALSE)
                {
                        $this->errno = MC_ERR_SOCKET_READ;
                        $this->errstr = "Failed to read from socket.";

                        if($this->debug)
                        {
                                $sockerr = socket_last_error($sock);
                                $this->_debug("delete(): socket_read() returned FALSE. Socket Error $sockerr: ".socket_strerror($sockerr));
                        }

                        return FALSE;
                }

                // remove the \r\n from the end
                $retval = rtrim($retval);

                // now read the server's response
                if($retval == "DELETED")
                        return TRUE;
                else
                {
                        // something went wrong, create the error
                        $this->errno = MC_ERR_DELETE;
                        $this->errstr = "Failed to receive DELETED response from server.";

                        if($this->debug)
                                $this->_debug("delete(): Failed to receive DELETED response from server. Received $retval instead.");

                        return FALSE;
                }
        }


        /**
         * Like set(), but only stores in memcache if the key doesn't already exist.
         * Possible errors set are:
         *                MC_ERR_NOT_ACTIVE
         *                MC_ERR_GET_SOCK
         *                MC_ERR_SOCKET_WRITE
         *                MC_ERR_SOCKET_READ
         *                MC_ERR_SET
         *
         * @access public
         * @param string $key the key to set
         * @param mixed $val the value of the key
         * @param timestamp $exptime optional, the to to live of the key
         * @return bool TRUE on success, else FALSE
         */
        function add($key, $val, $exptime = 0)
        {
                return $this->_set("add", $key, $val, $exptime);
        }


        /**
         * Like set(), but only stores in memcache if the key already exists.
         * returns TRUE on success else FALSE
         * Possible errors set are:
         *                MC_ERR_NOT_ACTIVE
         *                MC_ERR_GET_SOCK
         *                MC_ERR_SOCKET_WRITE
         *                MC_ERR_SOCKET_READ
         *                MC_ERR_SET
         *
         * @access public
         * @param string $key the key to set
         * @param mixed $val the value of the key
         * @param timestamp $exptime optional, the to to live of the key
         * @return bool TRUE on success, else FALSE
         */
        function replace($key, $val, $exptime = 0)
        {
                return $this->_set("replace", $key, $val, $exptime);
        }


        /**
         * Unconditionally sets a key to a given value in the memcache.  Returns true
         * if it was stored successfully.
         * The $key can optionally be an arrayref, with the first element being the
         * hash value, as described above.
         * Possible errors set are:
         *                MC_ERR_NOT_ACTIVE
         *                MC_ERR_GET_SOCK
         *                MC_ERR_SOCKET_WRITE
         *                MC_ERR_SOCKET_READ
         *                MC_ERR_SET
         *
         * @access public
         * @param string $key the key to set
         * @param mixed $val the value of the key
         * @param timestamp $exptime optional, the to to live of the key
         * @return bool TRUE on success, else FALSE
         */
        function set($key, $val, $exptime = 0)
        {
                return $this->_set("set", $key, $val, $exptime);
        }


        /**
         * Retrieves a key from the memcache.  Returns the value (automatically
         * unserialized, if necessary) or FALSE if it fails.
         * The $key can optionally be an array, with the first element being the
         * hash value, if you want to avoid making this module calculate a hash
         * value.  You may prefer, for example, to keep all of a given user's
         * objects on the same memcache server, so you could use the user's
         * unique id as the hash value.
         * Possible errors set are:
         *                MC_ERR_GET_KEY
         *
         * @access public
         * @param string $key the key to retrieve
         * @return mixed the value of the key, FALSE on error
         */
        function get($key)
        {
                $val =& $this->get_multi($key);

                if(!$val)
                {
                        $this->errno = MC_ERR_GET_KEY;
                        $this->errstr = "No value found for key $key";

                        if($this->debug)
                                $this->_debug("get(): No value found for key $key");

                        return FALSE;
                }

                return $val[$key];
        }


        /**
         * just like get(), but takes an array of keys, returns FALSE on error
         * Possible errors set are:
         *                MC_ERR_NOT_ACTIVE
         *
         * @access public
         * @param array $keys the keys to retrieve
         * @return array the value of each key, FALSE on error
         */
        function get_multi($keys)
        {
                $sock_keys = array();
                $socks = array();
                $val = 0;

                if(!$this->active)
                {
                        $this->errno = MC_ERR_NOT_ACTIVE;
                        $this->errstr = "No active servers are available";

                        if($this->debug)
                                $this->_debug("get_multi(): There are no active servers available.");

                        return FALSE;
                }

                if(!is_array($keys))
                {
                        $arr[] = $keys;
                        $keys = $arr;
                }

                foreach($keys as $k)
                {
                        $sock = $this->get_sock($k);

                        if($sock)
                        {
                                $k = is_array($k) ? $k[1] : $k;

                                if(!isset($sock_keys[$sock]) || !is_array($sock_keys[$sock]))
                                        $sock_keys[$sock] = array();

                                // if $sock_keys[$sock] doesn't exist, create it
                                if(!$sock_keys[$sock])
                                        $socks[] = $sock;

                                $sock_keys[$sock][] = $k;
                        }
                }

                if(!is_array($socks))
                {
                        $arr[] = $socks;
                        $socks = $arr;
                }

                foreach($socks as $s)
                {
                        $this->_load_items($s, $val, $sock_keys[$sock]);
                }

                if($this->debug)
                {
                        while(list($k, $v) = @each($val))
                                $this->_debug("MemCache: got $k = $v\n");
                }

                return $val;
        }


        /**
         * Sends a command to the server to atomically increment the value for
         * $key by $value, or by 1 if $value is undefined.  Returns FALSE if $key
         * doesn't exist on server, otherwise it returns the new value after
         * incrementing.  Value should be zero or greater.  Overflow on server
         * is not checked.  Be aware of values approaching 2**32.  See decr.
         * ONLY WORKS WITH NUMERIC VALUES
         * Possible errors set are:
         *                MC_ERR_NOT_ACTIVE
         *                MC_ERR_GET_SOCK
         *                MC_ERR_SOCKET_WRITE
         *                MC_ERR_SOCKET_READ
         *
         * @access public
         * @param string $key the keys to increment
         * @param int $value the amount to increment the key by
         * @return int the new value of the key, else FALSE
         */
        function incr($key, $value = 1)
        {
                return $this->_incrdecr("incr", $key, $value);
        }


        /**
         * Like incr, but decrements.  Unlike incr, underflow is checked and new
         * values are capped at 0.  If server value is 1, a decrement of 2
         * returns 0, not -1.
         * ONLY WORKS WITH NUMERIC VALUES
         * Possible errors set are:
         *                MC_ERR_NOT_ACTIVE
         *                MC_ERR_GET_SOCK
         *                MC_ERR_SOCKET_WRITE
         *                MC_ERR_SOCKET_READ
         *
         * @access public
         * @param string $key the keys to increment
         * @param int $value the amount to increment the key bye
         * @return int the new value of the key, else FALSE
         */
        function decr($key, $value = 1)
        {
                return $this->_incrdecr("decr", $key, $value);
        }


        /**
         * When a function returns FALSE, an error code is set.
         * This funtion will return the error code.
         * See error_string()
         *
         * @access public
         * @return int the value of the last error code
         */
        function error()
        {
                return $this->errno;
        }


        /**
         * Returns a string describing the error set in error()
         * See error()
         *
         * @access public
         * @return int a string describing the error code given
         */
        function error_string()
        {
                return $this->errstr;
        }


        /**
         * Resets the error number and error string
         *
         * @access public
         */
        function error_clear()
        {
                // reset to no error
                $this->errno = 0;
                $this->errstr = "";
        }


        /**
         *        temporarily sets compression on or off
         *        turning it off, and then back on will result in the compression threshold going
         *        back to the original setting from $options
         *        @param int $setting setting of compression (0=off|1=on)
         */

         function set_compression($setting=1) {
                 if ($setting != 0) {
                         $this->comp_active = 1;
                 } else {
                         $this->comp_active = 0;
                 }
         }



        /*
         * PRIVATE FUNCTIONS
         */


        /**
         * connects to a server
         * The $host may either a string int the form of host:port or an array of the
         * former and an integer weight value.  (the default weight if
         * unspecified is 1.) See the constructor for details
         * Possible errors set are:
         *                MC_ERR_HOST_FORMAT
         *                MC_ERR_HOST_DEAD
         *                MC_ERR_SOCKET_CONNECT
         *
         * @access private
         * @param mixed $host either an array or a string
         * @return resource the socket of the new connection, else FALSE
         */
        function sock_to_host($host)
        {
                if(is_array($host))
                        $host = array_shift($host);

                $now = time();

                // seperate the ip from the port, index 0 = ip, index 1 = port
                $conn = explode(":", $host);
                if(count($conn) != 2)
                {
                        $this->errno = MC_ERR_HOST_FORMAT;
                        $this->errstr = "Host address was not in the format of host:port";

                        if($this->debug)
                                $this->_debug("sock_to_host(): Host address was not in the format of host:port");

                        return FALSE;
                }

                if(@($this->host_dead[$host] && $this->host_dead[$host] > $now) ||
                @($this->host_dead[$conn[0]] && $this->host_dead[$conn[0]] > $now))
                {
                        $this->errno = MC_ERR_HOST_DEAD;
                        $this->errstr = "Host $host is not available.";

                        if($this->debug)
                                $this->_debug("sock_to_host(): Host $host is not available.");

                        return FALSE;
                }

                // connect to the server, if it fails, add it to the host_dead below
                $sock = socket_create (AF_INET, SOCK_STREAM, getprotobyname("TCP"));

                // we need surpress the error message if a connection fails
                if(!@socket_connect($sock, $conn[0], $conn[1]))
                {
                        $this->host_dead[$host]=$this->host_dead[$conn[0]]=$now+60+intval(rand(0, 10));

                        $this->errno = MC_ERR_SOCKET_CONNECT;
                        $this->errstr = "Failed to connect to ".$conn[0].":".$conn[1];

                        if($this->debug)
                                $this->_debug("sock_to_host(): Failed to connect to ".$conn[0].":".$conn[1]);

                        return FALSE;
                }

                // success, add to the list of sockets
                $cache_sock[$host] = $sock;

                return $sock;
        }


        /**
         * retrieves the socket associated with a key
         * Possible errors set are:
         *                MC_ERR_NOT_ACTIVE
         *                MC_ERR_GET_SOCK
         *
         * @access private
         * @param string $key the key to retrieve the socket from
         * @return resource the socket of the connection, else FALSE
         */
        function get_sock($key)
        {
                if(!$this->active)
                {
                        $this->errno = MC_ERR_NOT_ACTIVE;
                        $this->errstr = "No active servers are available";

                        if($this->debug)
                                $this->_debug("get_sock(): There are no active servers available.");

                        return FALSE;
                }

                $hv = is_array($key) ? intval($key[0]) : $this->_hashfunc($key);

                if(!isset($this->buckets))
                {
                        $bu = $this->buckets = array();

                        foreach($this->servers as $v)
                        {
                                if(is_array($v))
                                {
                                        for($i = 1;  $i <= $v[1]; ++$i)
                                                $bu[] =  $v[0];
                                }
                                else
                                        $bu[] = $v;
                        }

                        $this->buckets = $bu;
                }

                $real_key = is_array($key) ? $key[1] : $key;
                $tries = 0;
                while($tries < 20)
                {
                        $host = @$this->buckets[$hv % count($this->buckets)];
                        $sock = $this->sock_to_host($host);

                        if(is_resource($sock))
                                return $sock;

                        $hv += $this->_hashfunc($tries.$real_key);
                        ++$tries;
                }

                $this->errno = MC_ERR_GET_SOCK;
                $this->errstr = "Unable to retrieve a valid socket.";

                if($this->debug)
                        $this->_debug("get_sock(): Unable to retrieve a valid socket.");

                return FALSE;
        }


        /**
         * increments or decrements a numerical value in memcached. this function is
         * called from incr() and decr()
         * ONLY WORKS WITH NUMERIC VALUES
         * Possible errors set are:
         *                MC_ERR_NOT_ACTIVE
         *                MC_ERR_GET_SOCK
         *                MC_ERR_SOCKET_WRITE
         *                MC_ERR_SOCKET_READ
         *
         * @access private
         * @param string $cmdname the command to send, either incr or decr
         * @param string $key the key to perform the command on
         * @param mixed $value the value to incr or decr the key value by
         * @return int the new value of the key, FALSE if something went wrong
         */
        function _incrdecr($cmdname, $key, $value)
        {
                if(!$this->active)
                {
                        $this->errno = MC_ERR_NOT_ACTIVE;
                        $this->errstr = "No active servers are available";

                        if($this->debug)
                                $this->_debug("_incrdecr(): There are no active servers available.");

                        return FALSE;
                }

                $sock = $this->get_sock($key);
                if(!is_resource($sock))
                {
                        $this->errno = MC_ERR_GET_SOCK;
                        $this->errstr = "Unable to retrieve a valid socket.";

                        if($this->debug)
                                $this->_debug("_incrdecr(): Invalid socket returned by get_sock().");

                        return FALSE;
                }

                if($value == "")
                        $value = 1;

                $cmd = "$cmdname $key $value\r\n";
                $cmd_len = strlen($cmd);
                $offset = 0;

                // write the command to the server
                while($offset < $cmd_len)
                {
                        $result = socket_write($sock, substr($cmd, $offset, MC_BUFFER_SZ), MC_BUFFER_SZ);

                        if($result !== FALSE)
                                $offset += $result;
                        else if($offset < $cmd_len)
                        {
                                $this->errno = MC_ERR_SOCKET_WRITE;
                                $this->errstr = "Failed to write to socket.";

                                if($this->debug)
                                {
                                        $sockerr = socket_last_error($sock);
                                        $this->_debug("_incrdecr(): socket_write() returned FALSE. Error $errno: ".socket_strerror($sockerr));
                                }

                                return FALSE;
                        }
                }

                // now read the server's response
                if(($retval = socket_read($sock, MC_BUFFER_SZ, PHP_NORMAL_READ)) === FALSE)
                {
                        $this->errno = MC_ERR_SOCKET_READ;
                        $this->errstr = "Failed to read from socket.";

                        if($this->debug)
                        {
                                $sockerr = socket_last_error($sock);
                                $this->_debug("_incrdecr(): socket_read() returned FALSE. Socket Error $errno: ".socket_strerror($sockerr));
                        }

                        return FALSE;
                }

                // strip the /r/n from the end and return value
                return trim($retval);
        }

        /**
         * sends the command to the server
         * Possible errors set are:
         *                MC_ERR_NOT_ACTIVE
         *                MC_ERR_GET_SOCK
         *                MC_ERR_SOCKET_WRITE
         *                MC_ERR_SOCKET_READ
         *                MC_ERR_SET
         *
         * @access private
         * @param string $cmdname the command to send, either incr or decr
         * @param string $key the key to perform the command on
         * @param mixed $value the value to set the key to
         * @param timestamp $exptime expiration time of the key
         * @return bool TRUE on success, else FALSE
         */
        function _set($cmdname, $key, $val, $exptime = 0)
        {
                if(!$this->active)
                {
                        $this->errno = MC_ERR_NOT_ACTIVE;
                        $this->errstr = "No active servers are available";

                        if($this->debug)
                                $this->_debug("_set(): No active servers are available.");

                        return FALSE;
                }

                $sock = $this->get_sock($key);
                if(!is_resource($sock))
                {
                        $this->errno = MC_ERR_GET_SOCK;
                        $this->errstr = "Unable to retrieve a valid socket.";

                        if($this->debug)
                                $this->_debug("_set(): Invalid socket returned by get_sock().");

                        return FALSE;
                }

                $flags = 0;
                $key = is_array($key) ? $key[1] : $key;

                $raw_val = $val;

                // if the value is not scalar, we need to serialize it
                if(!is_scalar($val))
                {
                        $val = serialize($val);
                        $flags |= 1;
                }

                if (($this->compress > 0) && (strlen($val) > $this->compress)) {
                        $this->_debug("_set(): compressing data. size in:".strlen($val));
                        $cval=gzcompress($val);
                        $this->_debug("_set(): done compressing data. size out:".strlen($cval));
                        if ((strlen($cval) < strlen($val)) && (strlen($val) - strlen($cval) > 2048)){
                                $flags |= 2;
                                $val=$cval;
                        }
                        unset($cval);
                }

                $len = strlen($val);
                if (!is_int($exptime))
                        $exptime = 0;

                // send off the request
                $cmd = "$cmdname $key $flags $exptime $len\r\n$val\r\n";
                $cmd_len = strlen($cmd);
                $offset = 0;

                // write the command to the server
                while($offset < $cmd_len)
                {
                        $result = socket_write($sock, substr($cmd, $offset, MC_BUFFER_SZ), MC_BUFFER_SZ);

                        if($result !== FALSE)
                                $offset += $result;
                        else if($offset < $cmd_len)
                        {
                                $this->errno = MC_ERR_SOCKET_WRITE;
                                $this->errstr = "Failed to write to socket.";

                                if($this->debug)
                                {
                                        $errno = socket_last_error($sock);
                                        $this->_debug("_set(): socket_write() returned FALSE. Error $errno: ".socket_strerror($errno));
                                }

                                return FALSE;
                        }
                }

                // now read the server's response
                if(($l_szResponse = socket_read($sock, 6, PHP_NORMAL_READ)) === FALSE)
                {
                        $this->errno = MC_ERR_SOCKET_READ;
                        $this->errstr = "Failed to read from socket.";

                        if($this->debug)
                        {
                                $errno = socket_last_error($sock);
                                $this->_debug("_set(): socket_read() returned FALSE. Error $errno: ".socket_strerror($errno));
                        }

                        return FALSE;
                }

                if($l_szResponse == "STORED")
                {
                        if($this->debug)
                                $this->_debug("MemCache: $cmdname $key = $raw_val");

                        return TRUE;
                }

                $this->errno = MC_ERR_SET;
                $this->errstr = "Failed to receive the STORED response from the server.";

                if($this->debug)
                        $this->_debug("_set(): Did not receive STORED as the server response! Received $l_szResponse instead.");

                return FALSE;
        }


        /**
         * retrieves the value, and returns it unserialized
         * Possible errors set are:
         *                MC_ERR_SOCKET_WRITE
         *                MC_ERR_SOCKET_READ
         *                MC_ERR_GET_KEY
         *                MC_ERR_LOADITEM_END
         *                MC_ERR_LOADITEM_BYTES
         *
         * @access private
         * @param resource $sock the socket to connection we are retriving from
         * @param array $val reference to the values retrieved
         * @param mixed $sock_keys either a string or an array of keys to retrieve
         * @return array TRUE on success, else FALSE
         */
        function _load_items($sock, &$val, $sock_keys)
        {
                $val = array();
                $cmd = "get ";

                if(!is_array($sock_keys))
                {
                        $arr[] = $sock_keys;
                        $sock_keys = $arr;
                }

                foreach($sock_keys as $sk)
                        $cmd .= $sk." ";

                $cmd .="\r\n";
                $cmd_len = strlen($cmd);
                $offset = 0;

                // write the command to the server
                while($offset < $cmd_len)
                {
                        $result = socket_write($sock, substr($cmd, $offset, MC_BUFFER_SZ), MC_BUFFER_SZ);

                        if($result !== FALSE)
                                $offset += $result;
                        else if($offset < $cmd_len)
                        {
                                $this->errno = MC_ERR_SOCKET_WRITE;
                                $this->errstr = "Failed to write to socket.";

                                if($this->debug)
                                {
                                        $errno = socket_last_error($sock);
                                        $this->_debug("_load_items(): socket_write() returned FALSE. Error $errno: ".socket_strerror($errno));
                                }

                                return FALSE;
                        }
                }

                $len = 0;
                $buf = "";
                $flags_array = array();

                // now read the response from the server
                while($line = socket_read($sock, MC_BUFFER_SZ, PHP_BINARY_READ))
                {
                        // check for a socket_read error
                        if($line === FALSE)
                        {
                                $this->errno = MC_ERR_SOCKET_READ;
                                $this->errstr = "Failed to read from socket.";

                                if($this->debug)
                                {
                                        $errno = socket_last_error($sock);
                                        $this->_debug("_load_items(): socket_read() returned FALSE. Error $errno: ".socket_strerror($errno));
                                }

                                return FALSE;
                        }

                        if($len == 0)
                        {
                                $header = substr($line, 0, strpos($line, "\r\n"));
                                $matches = explode(" ", $header);

                                if(isset($matches[1]) && isset($matches[2]) && isset($matches[3]) && is_string($matches[1]) && is_numeric($matches[2]) && is_numeric($matches[3]))
                                {
                                        $rk = $matches[1];
                                        $flags = $matches[2];
                                        $len = $matches[3];

                                        if($flags)
                                                $flags_array[$rk] = $flags;

                                        $len_array[$rk] = $len;
                                        $bytes_read = 0;

                                        // get the left over data after the header is read
                                        $line = substr($line, strpos($line, "\r\n")+2, strlen($line));
                                }
                                else
                                {
                                        $this->errno = MC_ERR_GET_KEY;
                                        $this->errstr = "Requested key(s) returned no values.";

                                        // something went wrong, we never recieved the header
                                        if($this->debug)
                                                $this->_debug("_load_items(): Requested key(s) returned no values.");

                                        return FALSE;
                                }
                        }

                        // skip over the extra return or newline
                        if($line == "\r" || $line == "\n")
                                continue;

                        $bytes_read += strlen($line);
                        $buf .= $line;

                        // we read the all of the data, take in account
                        // for the /r/nEND/r/n
                        if($bytes_read == ($len + 7))
                        {
                                $end = substr($buf, $len+2, 3);
                                if($end == "END")
                                {
                                        $val[$rk] = substr($buf, 0, $len);

                                        foreach($sock_keys as $sk)
                                        {
                                                if(!isset($val[$sk]) || !isset($flags_array[$sk]))
                                                        continue;

                                                if(strlen($val[$sk]) != $len_array[$sk])
                                                        continue;
                                                if(@$flags_array[$sk] & 2)
                                                        $val[$sk] = gzuncompress($val[$sk]);

                                                if(@$flags_array[$sk] & 1)
                                                        $val[$sk] = unserialize($val[$sk]);
                                        }

                                        return TRUE;
                                }
                                else
                                {
                                        $this->errno = MC_ERR_LOADITEM_END;
                                        $this->errstr = "Failed to receive END response from server.";

                                        if($this->debug)
                                                $this->_debug("_load_items(): Failed to receive END. Received $end instead.");

                                        return FALSE;
                                }
                        }

                        // take in consideration for the "\r\nEND\r\n"
                        if($bytes_read > ($len + 7))
                        {
                                $this->errno = MC_ERR_LOADITEM_BYTES;
                                $this->errstr = "Bytes read from server greater than size of data.";

                                if($this->debug)
                                        $this->_debug("_load_items(): Bytes read is greater than requested data size.");

                                return FALSE;
                        }

                }
        }


        /**
         * creates our hash
         *
         * @access private
         * @param int $num
         * @return hash
         */
        function _hashfunc($num)
        {
                $hash = sprintf("%u",crc32($num));

                return $hash;
        }

    /**
     * function that can be overridden to handle debug output
     * by default debug info is print to the screen
     *
     * @access private
     * @param $text string to output debug info
     */
    function _debug($text)
    {
                print $text . "\r\n";
    }
}