=> 'add_date_gteq',
		'date_lteq'       => 'add_date_lteq',
		'groupid'         => 'add_groupid',
		'members_gteq'    => 'add_members_gteq',
		'members_lteq'    => 'add_members_lteq',
		'discussion_gteq' => 'add_discussion_gteq',
		'discussion_lteq' => 'add_discussion_lteq',
		'message_gteq'    => 'add_messages_gteq',
		'message_lteq'    => 'add_messages_lteq',
		'picture_gteq'    => 'add_pictures_gteq',
		'picture_lteq'    => 'add_pictures_lteq',
		'member'          => 'add_member',
		'membertype'      => 'add_membertype',
		'creator'         => 'add_creator',
		'pending'         => 'add_pending',
		'type'            => 'add_type',
		'moderatedgms'    => 'add_moderatedgms',
		'subscribed'      => 'add_subscribed'
	);

	/**
	* List of valid sorting fields.
	* Key is the unique ID (from the form), value is the column name
	*
	* @var	array
	*/
	var $valid_sort = array(
		'members'     => 'socialgroup.members',
		'created'     => 'socialgroup.dateline',
		'name'        => 'socialgroup.name',
		'category'    => 'sgc.title',
		'pictures'    => 'socialgroup.picturecount', // see constructor: this is modified
		'messages'    => 'socialgroup.visible',
		'lastpost'    => 'socialgroup.lastpost',
		'discussions' => 'socialgroup.discussions'
	);

	/**
	* @var	vB_Registry
	*/
	var $registry = null;

	/**
	* List of errors (DM style)
	*
	* @var	array
	*/
	var $errors = array();

	/**
	* Where clause pieces. Will be ANDed together
	*
	* @var	array
	*/
	var $where = array();

	/**
	* List of joins necessary
	*
	* @var	array
	*/
	var $joins = array();

	/**
	* The Query Limit offset
	*
	* @var	integer
	*/
	var $limitoffset = 0;

	/**
	* The Query Limit
	*
	* @var	integer
	*/
	var $limit = 0;

	/**
	* Constructor.
	*
	* @param	vB_Registry
	*/
	function vB_SGSearchGenerator(&$registry)
	{
		$this->registry =& $registry;

		// need to update the picture count
		if (isset($this->valid_sort['pictures']))
		{
			$this->valid_sort['pictures'] = 'IF(socialgroup.options & ' . $registry->bf_misc_socialgroupoptions['enable_group_albums'] . ', socialgroup.picturecount, 0)';
		}
	}

	/**
	* Determines whether the current search has errors
	*
	* @return	boolean
	*/
	function has_errors()
	{
		return !empty($this->errors);
	}

	/**
	* Verifies the sorting field and grabs the necessary data
	*
	* @param	string	(In/Out) The specified sort field, translated to the column name
	* @param	string	(In/Out) The specified sort order, translated to the appropriate safe value
	* @param	string	(Output) Raw sort field passed in
	* @param	string	(Output) Raw sort order passed in
	*
	* @return	bool	Returns true unless something fails. (Always returns true right now)
	*/
	function verify_sort(&$sort, &$sortorder, &$sort_raw, &$sortorder_raw, &$sort_criteria)
	{
		$sort_raw = $sort;
		$sortorder_raw = $sortorder;

		if (!isset($this->valid_sort["$sort"]))
		{
			$sort = 'socialgroup.dateline';
			$sort_raw = 'dateline';
		}
		else
		{
			$sort = $this->valid_sort["$sort"];
		}

		switch (strtolower($sortorder))
		{
			case 'asc':
			case 'desc':
				break;
			default:
				$sortorder = 'DESC';
				$sortorder_raw = 'DESC';
		}

		$sort_criteria = $sort . ' ' . $sortorder;

		if ($sort_raw != 'created')
		{
			$newsort = 'created';
			$newsort_order = $sortorder;
			$this->verify_sort($newsort, $newsort_order, $newsort_raw, $newsort_order_raw, $newsort_criteria);
			$sort_criteria .= ', ' . $newsort_criteria;
		}

		return true;
	}

	/**
	* Adds a search criteria
	*
	* @param	string	Name of criteria
	* @param	mixed	How to restrict the criteria
	*
	* @return	boolean	True on success
	*/
	function add($name, $value)
	{
		if (!isset($this->valid_fields["$name"]))
		{
			$this->error('sg_search_field_x_unknown', htmlspecialchars_uni($name));
			return SG_SEARCHGEN_CRITERIA_FAILED;
		}

		$raw = $value;
		$add_method = $this->valid_fields["$name"];
		return $this->$add_method($name, $value);
	}

	/**
	* Adds an error to the list, phrased for the current user. 1 or more arguments
	*
	* @param	string	Error phrase name
	*/
	function error($errorphrase)
	{
		$args = func_get_args();

		if (is_array($errorphrase))
		{
			$error = fetch_error($errorphrase);
		}
		else
		{
			$error = call_user_func_array('fetch_error', $args);
		}

		$this->errors[] = $error;
	}

	/**
	* Generates the search query bits
	*
	* @return	array|false	False if error, array consisting of joins and where clause otherwise
	*/
	function generate()
	{
		if (!$this->has_errors())
		{
			if (!empty($this->limit))
			{
				$limit = "LIMIT " . (!empty($this->limitoffset) ? $this->limitoffset . ',' : '') . $this->limit;
			}
			else
			{
				$limit = '';
			}

			return array(
				'columns' => '',
				'joins'   => implode("\n", $this->joins),
				'where'   => implode("\nAND ", $this->where),
				'limit'   => $limit
			);
		}
		else
		{
			return false;
		}
	}

	/**
	* Prepares a criteria that may either be a scalar or an array
	*
	* @param	mixed		Value to process
	* @param	callback	Callback function to call on each value
	* @param	string		Text to implode the array with
	*
	* @return	mixed		Returns true if the array is empty, otherwise the processed values
	*/
	function prepare_scalar_array($value, $callback = '', $array_splitter = ',')
	{
		if (is_array($value))
		{
			if ($callback)
			{
				$value = array_map($callback, $value);
			}

			$value = array_values($value);
			if (count($value) == 0 OR (count($value) == 1 AND empty($value[0])))
			{
				return call_user_func($callback, '');
			}
			else
			{
				return implode($array_splitter, $value);
			}
		}
		else if ($callback)
		{
			return call_user_func($callback, $value);
		}
		else
		{
			return $value;
		}
	}

	/**
	* Adds group ID criteria
	*
	* @param	string
	* @param	integer|array
	*
	* @return	bool