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<?php

/**

*

* @package search

* @copyright (c) 2005 phpBB Group

* @license http://opensource.org/licenses/gpl-2.0.php GNU General Public License v2

*

*/

/**

* @ignore

*/

if (!defined('IN_PHPBB'))

{

        exit;

}

/**

* fulltext_mysql

* Fulltext search for MySQL

* @package search

*/

class phpbb_search_fulltext_mysql extends phpbb_search_base

{

        var $stats = array();

        var $word_length = array();

        var $split_words = array();

        var $search_query;

        var $common_words = array();

        var $pcre_properties = false;

        var $mbstring_regex = false;

        public function __construct(&$error)

        {

                global $config;

                $this->word_length = array('min' => $config['fulltext_mysql_min_word_len'], 'max' => $config['fulltext_mysql_max_word_len']);

                // PHP may not be linked with the bundled PCRE lib and instead with an older version

                if (phpbb_pcre_utf8_support())

                {

                        $this->pcre_properties = true;

                }

                if (function_exists('mb_ereg'))

                {

                        $this->mbstring_regex = true;

                        mb_regex_encoding('UTF-8');

                }

                $error = false;

        }

        /**

        * Returns the name of this search backend to be displayed to administrators

        *

        * @return string Name

        */

        public function get_name()

        {

                return 'MySQL Fulltext';

        }

        /**

        * Checks for correct MySQL version and stores min/max word length in the config

        */

        function init()

        {

                global $db, $user;

                if ($db->sql_layer != 'mysql4' && $db->sql_layer != 'mysqli')

                {

                        return $user->lang['FULLTEXT_MYSQL_INCOMPATIBLE_VERSION'];

                }

                $result = $db->sql_query('SHOW TABLE STATUS LIKE \'' . POSTS_TABLE . '\'');

                $info = $db->sql_fetchrow($result);

                $db->sql_freeresult($result);

                $engine = '';

                if (isset($info['Engine']))

                {

                        $engine = $info['Engine'];

                }

                else if (isset($info['Type']))

                {

                        $engine = $info['Type'];

                }

                if ($engine != 'MyISAM')

                {

                        return $user->lang['FULLTEXT_MYSQL_NOT_MYISAM'];

                }

                $sql = 'SHOW VARIABLES

                        LIKE \'ft\_%\'';

                $result = $db->sql_query($sql);

                $mysql_info = array();

                while ($row = $db->sql_fetchrow($result))

                {

                        $mysql_info[$row['Variable_name']] = $row['Value'];

                }

                $db->sql_freeresult($result);

                set_config('fulltext_mysql_max_word_len', $mysql_info['ft_max_word_len']);

                set_config('fulltext_mysql_min_word_len', $mysql_info['ft_min_word_len']);

                return false;

        }

        /**

        * Splits keywords entered by a user into an array of words stored in $this->split_words

        * Stores the tidied search query in $this->search_query

        *

        * @param string &$keywords Contains the keyword as entered by the user

        * @param string $terms is either 'all' or 'any'

        * @return bool false if no valid keywords were found and otherwise true

        */

        function split_keywords(&$keywords, $terms)

        {

                global $config, $user;

                if ($terms == 'all')

                {

                        $match                = array('#\sand\s#iu', '#\sor\s#iu', '#\snot\s#iu', '#(^|\s)\+#', '#(^|\s)-#', '#(^|\s)\|#');

                        $replace        = array(' +', ' |', ' -', ' +', ' -', ' |');

                        $keywords = preg_replace($match, $replace, $keywords);

                }

                // Filter out as above

                $split_keywords = preg_replace("#[\n\r\t]+#", ' ', trim(htmlspecialchars_decode($keywords)));

                // Split words

                if ($this->pcre_properties)

                {

                        $split_keywords = preg_replace('#([^\p{L}\p{N}\'*"()])#u', '$1$1', str_replace('\'\'', '\' \'', trim($split_keywords)));

                }

                else if ($this->mbstring_regex)

                {

                        $split_keywords = mb_ereg_replace('([^\w\'*"()])', '\\1\\1', str_replace('\'\'', '\' \'', trim($split_keywords)));

                }

                else

                {

                        $split_keywords = preg_replace('#([^\w\'*"()])#u', '$1$1', str_replace('\'\'', '\' \'', trim($split_keywords)));

                }

                if ($this->pcre_properties)

                {

                        $matches = array();

                        preg_match_all('#(?:[^\p{L}\p{N}*"()]|^)([+\-|]?(?:[\p{L}\p{N}*"()]+\'?)*[\p{L}\p{N}*"()])(?:[^\p{L}\p{N}*"()]|$)#u', $split_keywords, $matches);

                        $this->split_words = $matches[1];

                }

                else if ($this->mbstring_regex)

                {

                        mb_ereg_search_init($split_keywords, '(?:[^\w*"()]|^)([+\-|]?(?:[\w*"()]+\'?)*[\w*"()])(?:[^\w*"()]|$)');

                        while (($word = mb_ereg_search_regs()))

                        {

                                $this->split_words[] = $word[1];

                        }

                }

                else

                {

                        $matches = array();

                        preg_match_all('#(?:[^\w*"()]|^)([+\-|]?(?:[\w*"()]+\'?)*[\w*"()])(?:[^\w*"()]|$)#u', $split_keywords, $matches);

                        $this->split_words = $matches[1];

                }

                // We limit the number of allowed keywords to minimize load on the database

                if ($config['max_num_search_keywords'] && sizeof($this->split_words) > $config['max_num_search_keywords'])

                {

                        trigger_error($user->lang('MAX_NUM_SEARCH_KEYWORDS_REFINE', $config['max_num_search_keywords'], sizeof($this->split_words)));

                }

                // to allow phrase search, we need to concatenate quoted words

                $tmp_split_words = array();

                $phrase = '';

                foreach ($this->split_words as $word)

                {

                        if ($phrase)

                        {

                                $phrase .= ' ' . $word;

                                if (strpos($word, '"') !== false && substr_count($word, '"') % 2 == 1)

                                {

                                        $tmp_split_words[] = $phrase;

                                        $phrase = '';

                                }

                        }

                        else if (strpos($word, '"') !== false && substr_count($word, '"') % 2 == 1)

                        {

                                $phrase = $word;

                        }

                        else

                        {

                                $tmp_split_words[] = $word . ' ';

                        }

                }

                if ($phrase)

                {

                        $tmp_split_words[] = $phrase;

                }

                $this->split_words = $tmp_split_words;

                unset($tmp_split_words);

                unset($phrase);

                foreach ($this->split_words as $i => $word)

                {

                        $clean_word = preg_replace('#^[+\-|"]#', '', $word);

                        // check word length

                        $clean_len = utf8_strlen(str_replace('*', '', $clean_word));

                        if (($clean_len < $config['fulltext_mysql_min_word_len']) || ($clean_len > $config['fulltext_mysql_max_word_len']))

                        {

                                $this->common_words[] = $word;

                                unset($this->split_words[$i]);

                        }

                }

                if ($terms == 'any')

                {

                        $this->search_query = '';

                        foreach ($this->split_words as $word)

                        {

                                if ((strpos($word, '+') === 0) || (strpos($word, '-') === 0) || (strpos($word, '|') === 0))

                                {

                                        $word = substr($word, 1);

                                }

                                $this->search_query .= $word . ' ';

                        }

                }

                else

                {

                        $this->search_query = '';

                        foreach ($this->split_words as $word)

                        {

                                if ((strpos($word, '+') === 0) || (strpos($word, '-') === 0))

                                {

                                        $this->search_query .= $word . ' ';

                                }

                                else if (strpos($word, '|') === 0)

                                {

                                        $this->search_query .= substr($word, 1) . ' ';

                                }

                                else

                                {

                                        $this->search_query .= '+' . $word . ' ';

                                }

                        }

                }

                $this->search_query = utf8_htmlspecialchars($this->search_query);

                if ($this->search_query)

                {

                        $this->split_words = array_values($this->split_words);

                        sort($this->split_words);

                        return true;

                }

                return false;

        }

        /**

        * Turns text into an array of words

        */

        function split_message($text)

        {

                global $config;

                // Split words

                if ($this->pcre_properties)

                {

                        $text = preg_replace('#([^\p{L}\p{N}\'*])#u', '$1$1', str_replace('\'\'', '\' \'', trim($text)));

                }

                else if ($this->mbstring_regex)

                {

                        $text = mb_ereg_replace('([^\w\'*])', '\\1\\1', str_replace('\'\'', '\' \'', trim($text)));

                }

                else

                {

                        $text = preg_replace('#([^\w\'*])#u', '$1$1', str_replace('\'\'', '\' \'', trim($text)));

                }

                if ($this->pcre_properties)

                {

                        $matches = array();

                        preg_match_all('#(?:[^\p{L}\p{N}*]|^)([+\-|]?(?:[\p{L}\p{N}*]+\'?)*[\p{L}\p{N}*])(?:[^\p{L}\p{N}*]|$)#u', $text, $matches);

                        $text = $matches[1];

                }

                else if ($this->mbstring_regex)

                {

                        mb_ereg_search_init($text, '(?:[^\w*]|^)([+\-|]?(?:[\w*]+\'?)*[\w*])(?:[^\w*]|$)');

                        $text = array();

                        while (($word = mb_ereg_search_regs()))

                        {

                                $text[] = $word[1];

                        }

                }

                else

                {

                        $matches = array();

                        preg_match_all('#(?:[^\w*]|^)([+\-|]?(?:[\w*]+\'?)*[\w*])(?:[^\w*]|$)#u', $text, $matches);

                        $text = $matches[1];

                }

                // remove too short or too long words

                $text = array_values($text);

                for ($i = 0, $n = sizeof($text); $i < $n; $i++)

                {

                        $text[$i] = trim($text[$i]);

                        if (utf8_strlen($text[$i]) < $config['fulltext_mysql_min_word_len'] || utf8_strlen($text[$i]) > $config['fulltext_mysql_max_word_len'])

                        {

                                unset($text[$i]);

                        }

                }

                return array_values($text);

        }

        /**

        * Performs a search on keywords depending on display specific params. You have to run split_keywords() first.

        *

        * @param        string                $type                                contains either posts or topics depending on what should be searched for

        * @param        string                $fields                                contains either titleonly (topic titles should be searched), msgonly (only message bodies should be searched), firstpost (only subject and body of the first post should be searched) or all (all post bodies and subjects should be searched)

        * @param        string                $terms                                is either 'all' (use query as entered, words without prefix should default to "have to be in field") or 'any' (ignore search query parts and just return all posts that contain any of the specified words)

        * @param        array                $sort_by_sql                contains SQL code for the ORDER BY part of a query

        * @param        string                $sort_key                        is the key of $sort_by_sql for the selected sorting

        * @param        string                $sort_dir                        is either a or d representing ASC and DESC

        * @param        string                $sort_days                        specifies the maximum amount of days a post may be old

        * @param        array                $ex_fid_ary                        specifies an array of forum ids which should not be searched

        * @param        array                $m_approve_fid_ary        specifies an array of forum ids in which the searcher is allowed to view unapproved posts

        * @param        int                        $topic_id                        is set to 0 or a topic id, if it is not 0 then only posts in this topic should be searched

        * @param        array                $author_ary                        an array of author ids if the author should be ignored during the search the array is empty

        * @param        string                $author_name                specifies the author match, when ANONYMOUS is also a search-match

        * @param        array                &$id_ary                        passed by reference, to be filled with ids for the page specified by $start and $per_page, should be ordered

        * @param        int                        $start                                indicates the first index of the page

        * @param        int                        $per_page                        number of ids each page is supposed to contain

        * @return        boolean|int                                                total number of results

        *

        * @access        public

        */

        function keyword_search($type, $fields, $terms, $sort_by_sql, $sort_key, $sort_dir, $sort_days, $ex_fid_ary, $m_approve_fid_ary, $topic_id, $author_ary, $author_name, &$id_ary, $start, $per_page)

        {

                global $config, $db;

                // No keywords? No posts.

                if (!$this->search_query)

                {

                        return false;

                }

                // generate a search_key from all the options to identify the results

                $search_key = md5(implode('#', array(

                        implode(', ', $this->split_words),

                        $type,

                        $fields,

                        $terms,

                        $sort_days,

                        $sort_key,

                        $topic_id,

                        implode(',', $ex_fid_ary),

                        implode(',', $m_approve_fid_ary),

                        implode(',', $author_ary)

                )));

                // try reading the results from cache

                $result_count = 0;

                if ($this->obtain_ids($search_key, $result_count, $id_ary, $start, $per_page, $sort_dir) == SEARCH_RESULT_IN_CACHE)

                {

                        return $result_count;

                }

                $id_ary = array();

                $join_topic = ($type == 'posts') ? false : true;

                // Build sql strings for sorting

                $sql_sort = $sort_by_sql[$sort_key] . (($sort_dir == 'a') ? ' ASC' : ' DESC');

                $sql_sort_table = $sql_sort_join = '';

                switch ($sql_sort[0])

                {

                        case 'u':

                                $sql_sort_table        = USERS_TABLE . ' u, ';

                                $sql_sort_join        = ($type == 'posts') ? ' AND u.user_id = p.poster_id ' : ' AND u.user_id = t.topic_poster ';

                        break;

                        case 't':

                                $join_topic = true;

                        break;

                        case 'f':

                                $sql_sort_table        = FORUMS_TABLE . ' f, ';

                                $sql_sort_join        = ' AND f.forum_id = p.forum_id ';

                        break;

                }

                // Build some display specific sql strings

                switch ($fields)

                {

                        case 'titleonly':

                                $sql_match = 'p.post_subject';

                                $sql_match_where = ' AND p.post_id = t.topic_first_post_id';

                                $join_topic = true;

                        break;

                        case 'msgonly':

                                $sql_match = 'p.post_text';

                                $sql_match_where = '';

                        break;

                        case 'firstpost':

                                $sql_match = 'p.post_subject, p.post_text';

                                $sql_match_where = ' AND p.post_id = t.topic_first_post_id';

                                $join_topic = true;

                        break;

                        default:

                                $sql_match = 'p.post_subject, p.post_text';

                                $sql_match_where = '';

                        break;

                }

                if (!sizeof($m_approve_fid_ary))

                {

                        $m_approve_fid_sql = ' AND p.post_approved = 1';

                }

                else if ($m_approve_fid_ary === array(-1))

                {

                        $m_approve_fid_sql = '';

                }

                else

                {

                        $m_approve_fid_sql = ' AND (p.post_approved = 1 OR ' . $db->sql_in_set('p.forum_id', $m_approve_fid_ary, true) . ')';

                }

                $sql_select                        = (!$result_count) ? 'SQL_CALC_FOUND_ROWS ' : '';

                $sql_select                        = ($type == 'posts') ? $sql_select . 'p.post_id' : 'DISTINCT ' . $sql_select . 't.topic_id';

                $sql_from                        = ($join_topic) ? TOPICS_TABLE . ' t, ' : '';

                $field                                = ($type == 'posts') ? 'post_id' : 'topic_id';

                if (sizeof($author_ary) && $author_name)

                {

                        // first one matches post of registered users, second one guests and deleted users

                        $sql_author = ' AND (' . $db->sql_in_set('p.poster_id', array_diff($author_ary, array(ANONYMOUS)), false, true) . ' OR p.post_username ' . $author_name . ')';

                }

                else if (sizeof($author_ary))

                {

                        $sql_author = ' AND ' . $db->sql_in_set('p.poster_id', $author_ary);

                }

                else

                {

                        $sql_author = '';

                }

                $sql_where_options = $sql_sort_join;

                $sql_where_options .= ($topic_id) ? ' AND p.topic_id = ' . $topic_id : '';

                $sql_where_options .= ($join_topic) ? ' AND t.topic_id = p.topic_id' : '';

                $sql_where_options .= (sizeof($ex_fid_ary)) ? ' AND ' . $db->sql_in_set('p.forum_id', $ex_fid_ary, true) : '';

                $sql_where_options .= $m_approve_fid_sql;

                $sql_where_options .= $sql_author;

                $sql_where_options .= ($sort_days) ? ' AND p.post_time >= ' . (time() - ($sort_days * 86400)) : '';

                $sql_where_options .= $sql_match_where;

                $sql = "SELECT $sql_select

                        FROM $sql_from$sql_sort_table" . POSTS_TABLE . " p

                        WHERE MATCH ($sql_match) AGAINST ('" . $db->sql_escape(htmlspecialchars_decode($this->search_query)) . "' IN BOOLEAN MODE)

                                $sql_where_options

                        ORDER BY $sql_sort";

                $result = $db->sql_query_limit($sql, $config['search_block_size'], $start);

                while ($row = $db->sql_fetchrow($result))

                {

                        $id_ary[] = (int) $row[$field];

                }

                $db->sql_freeresult($result);

                $id_ary = array_unique($id_ary);

                if (!sizeof($id_ary))

                {

                        return false;

                }

                // if the total result count is not cached yet, retrieve it from the db

                if (!$result_count)

                {

                        $sql = 'SELECT FOUND_ROWS() as result_count';

                        $result = $db->sql_query($sql);

                        $result_count = (int) $db->sql_fetchfield('result_count');

                        $db->sql_freeresult($result);

                        if (!$result_count)

                        {

                                return false;

                        }

                }

                // store the ids, from start on then delete anything that isn't on the current page because we only need ids for one page

                $this->save_ids($search_key, implode(' ', $this->split_words), $author_ary, $result_count, $id_ary, $start, $sort_dir);

                $id_ary = array_slice($id_ary, 0, (int) $per_page);

                return $result_count;

        }

        /**

        * Performs a search on an author's posts without caring about message contents. Depends on display specific params

        *

        * @param        string                $type                                contains either posts or topics depending on what should be searched for

        * @param        boolean                $firstpost_only                if true, only topic starting posts will be considered

        * @param        array                $sort_by_sql                contains SQL code for the ORDER BY part of a query

        * @param        string                $sort_key                        is the key of $sort_by_sql for the selected sorting

        * @param        string                $sort_dir                        is either a or d representing ASC and DESC

        * @param        string                $sort_days                        specifies the maximum amount of days a post may be old

        * @param        array                $ex_fid_ary                        specifies an array of forum ids which should not be searched

        * @param        array                $m_approve_fid_ary        specifies an array of forum ids in which the searcher is allowed to view unapproved posts

        * @param        int                        $topic_id                        is set to 0 or a topic id, if it is not 0 then only posts in this topic should be searched

        * @param        array                $author_ary                        an array of author ids

        * @param        string                $author_name                specifies the author match, when ANONYMOUS is also a search-match

        * @param        array                &$id_ary                        passed by reference, to be filled with ids for the page specified by $start and $per_page, should be ordered

        * @param        int                        $start                                indicates the first index of the page

        * @param        int                        $per_page                        number of ids each page is supposed to contain

        * @return        boolean|int                                                total number of results

        *

        * @access        public

        */

        function author_search($type, $firstpost_only, $sort_by_sql, $sort_key, $sort_dir, $sort_days, $ex_fid_ary, $m_approve_fid_ary, $topic_id, $author_ary, $author_name, &$id_ary, $start, $per_page)

        {

                global $config, $db;

                // No author? No posts.

                if (!sizeof($author_ary))

                {

                        return 0;

                }

                // generate a search_key from all the options to identify the results

                $search_key = md5(implode('#', array(

                        '',

                        $type,

                        ($firstpost_only) ? 'firstpost' : '',

                        '',

                        '',

                        $sort_days,

                        $sort_key,

                        $topic_id,

                        implode(',', $ex_fid_ary),

                        implode(',', $m_approve_fid_ary),

                        implode(',', $author_ary),

                        $author_name,

                )));

                // try reading the results from cache

                $result_count = 0;

                if ($this->obtain_ids($search_key, $result_count, $id_ary, $start, $per_page, $sort_dir) == SEARCH_RESULT_IN_CACHE)

                {

                        return $result_count;

                }

                $id_ary = array();

                // Create some display specific sql strings

                if ($author_name)

                {

                        // first one matches post of registered users, second one guests and deleted users

                        $sql_author = '(' . $db->sql_in_set('p.poster_id', array_diff($author_ary, array(ANONYMOUS)), false, true) . ' OR p.post_username ' . $author_name . ')';

                }

                else

                {

                        $sql_author = $db->sql_in_set('p.poster_id', $author_ary);

                }

                $sql_fora                = (sizeof($ex_fid_ary)) ? ' AND ' . $db->sql_in_set('p.forum_id', $ex_fid_ary, true) : '';

                $sql_topic_id        = ($topic_id) ? ' AND p.topic_id = ' . (int) $topic_id : '';

                $sql_time                = ($sort_days) ? ' AND p.post_time >= ' . (time() - ($sort_days * 86400)) : '';

                $sql_firstpost = ($firstpost_only) ? ' AND p.post_id = t.topic_first_post_id' : '';

                // Build sql strings for sorting

                $sql_sort = $sort_by_sql[$sort_key] . (($sort_dir == 'a') ? ' ASC' : ' DESC');

                $sql_sort_table = $sql_sort_join = '';

                switch ($sql_sort[0])

                {

                        case 'u':

                                $sql_sort_table        = USERS_TABLE . ' u, ';

                                $sql_sort_join        = ($type == 'posts') ? ' AND u.user_id = p.poster_id ' : ' AND u.user_id = t.topic_poster ';

                        break;

                        case 't':

                                $sql_sort_table        = ($type == 'posts' && !$firstpost_only) ? TOPICS_TABLE . ' t, ' : '';

                                $sql_sort_join        = ($type == 'posts' && !$firstpost_only) ? ' AND t.topic_id = p.topic_id ' : '';

                        break;

                        case 'f':

                                $sql_sort_table        = FORUMS_TABLE . ' f, ';

                                $sql_sort_join        = ' AND f.forum_id = p.forum_id ';

                        break;

                }

                if (!sizeof($m_approve_fid_ary))

                {

                        $m_approve_fid_sql = ' AND p.post_approved = 1';

                }

                else if ($m_approve_fid_ary == array(-1))

                {

                        $m_approve_fid_sql = '';

                }

                else

                {

                        $m_approve_fid_sql = ' AND (p.post_approved = 1 OR ' . $db->sql_in_set('p.forum_id', $m_approve_fid_ary, true) . ')';

                }

                // If the cache was completely empty count the results

                $calc_results = ($result_count) ? '' : 'SQL_CALC_FOUND_ROWS ';

                // Build the query for really selecting the post_ids

                if ($type == 'posts')

                {

                        $sql = "SELECT {$calc_results}p.post_id

                                FROM " . $sql_sort_table . POSTS_TABLE . ' p' . (($firstpost_only) ? ', ' . TOPICS_TABLE . ' t ' : ' ') . "

                                WHERE $sql_author

                                        $sql_topic_id

                                        $sql_firstpost

                                        $m_approve_fid_sql

                                        $sql_fora

                                        $sql_sort_join

                                        $sql_time

                                ORDER BY $sql_sort";

                        $field = 'post_id';

                }

                else

                {

                        $sql = "SELECT {$calc_results}t.topic_id

                                FROM " . $sql_sort_table . TOPICS_TABLE . ' t, ' . POSTS_TABLE . " p

                                WHERE $sql_author

                                        $sql_topic_id

                                        $sql_firstpost

                                        $m_approve_fid_sql

                                        $sql_fora

                                        AND t.topic_id = p.topic_id

                                        $sql_sort_join

                                        $sql_time

                                GROUP BY t.topic_id

                                ORDER BY $sql_sort";

                        $field = 'topic_id';

                }

                // Only read one block of posts from the db and then cache it

                $result = $db->sql_query_limit($sql, $config['search_block_size'], $start);

                while ($row = $db->sql_fetchrow($result))

                {

                        $id_ary[] = (int) $row[$field];

                }

                $db->sql_freeresult($result);

                // retrieve the total result count if needed

                if (!$result_count)

                {

                        $sql = 'SELECT FOUND_ROWS() as result_count';

                        $result = $db->sql_query($sql);

                        $result_count = (int) $db->sql_fetchfield('result_count');

                        $db->sql_freeresult($result);

                        if (!$result_count)

                        {

                                return false;

                        }

                }

                if (sizeof($id_ary))

                {

                        $this->save_ids($search_key, '', $author_ary, $result_count, $id_ary, $start, $sort_dir);

                        $id_ary = array_slice($id_ary, 0, $per_page);

                        return $result_count;

                }

                return false;

        }

        /**

        * Destroys cached search results, that contained one of the new words in a post so the results won't be outdated.

        *

        * @param string $mode contains the post mode: edit, post, reply, quote ...

        */

        function index($mode, $post_id, &$message, &$subject, $poster_id, $forum_id)

        {

                global $db;

                // Split old and new post/subject to obtain array of words

                $split_text = $this->split_message($message);

                $split_title = ($subject) ? $this->split_message($subject) : array();

                $words = array_unique(array_merge($split_text, $split_title));

                unset($split_text);

                unset($split_title);

                // destroy cached search results containing any of the words removed or added

                $this->destroy_cache($words, array($poster_id));

                unset($words);

        }

        /**

        * Destroy cached results, that might be outdated after deleting a post

        */

        function index_remove($post_ids, $author_ids, $forum_ids)

        {

                $this->destroy_cache(array(), $author_ids);

        }

        /**

        * Destroy old cache entries

        */

        function tidy()

        {

                global $db, $config;

                // destroy too old cached search results

                $this->destroy_cache(array());

                set_config('search_last_gc', time(), true);

        }

        /**

        * Create fulltext index

        */

        function create_index($acp_module, $u_action)