国外PHP代码的中文搜索

大家好，我用了askpert这个问吧程序，但是不支持中文搜索？如何修改才能支持中文搜索啊？默认源码是UTF8
感谢

下面为它的search代码：

<?
//
// Askpert
//
// Basic Search engine class
// search.php
//
// (C) 2004 W3matter LLC
// This is commercial software!
// Please read the license at:
// http://www.w3matter.com/license
//

// Handles indexing and searching
// Stores results in the database
//

class search
{
// The document being searched for
var $query;

// The document itself
var $document;

// query suff
var $keywords;
var $limit;
var $page;
var $pagesize;
var $results;

// Internal stuff
var $db;
var $words;
var $stopwords;

function search()
{
global $DEFAULT;

// Connect to database
$this->db = new database();
$this->db->connect();

// Loadup stopwords
$this->stopwords = array_flip(explode("|", str_replace(array("\n", "\r"), "", implode("|", file("lang/stopwords.txt")))));

// Create a document object
$this->document = new document();

return(TRUE);
}

// Conduct a query
function query()
{
global $DEFAULT;

// Create an empty set of results
$this->results = array();

// Parse the query string and remove stopwords
$text = @str_replace(array("\n", "\r"), " ", @strtolower(@trim($this->keywords)));
$words = @preg_split('/\W+/', $text, -1, PREG_SPLIT_NO_EMPTY);
if(@count($words) == 0)
return(FALSE);

$words = array_count_values($words);
$w = array();
reset($words);
while(list($word,$n) = each($words))
{
if(!$this->stopwords[$word])
{
$id = $this->db->get_keyword($word, FALSE);
if($id)
$out[] = $id;
}
}

if(count($out) == 0)
return(FALSE);

// Get ranked list of documents that match
$inlist = implode(",", array_values($out));
$docs = $this->db->getsql("SELECT docid, sum(score) AS rank
FROM ax_search
WHERE keywordid IN ($inlist)
GROUP BY docid
ORDER BY rank DESC
LIMIT 100");

if(count($docs) == 0)
return(FALSE);

// Loadup the list of documents
foreach($docs as $rec)
{
$d = $this->db->getsql("SELECT id,subject,content FROM ax_questions WHERE id='$rec[docid]'");
if($d[0][id])
{
$x = new document();
$x->id = $d[0][id];
$x->title = stripslashes($d[0][subject]);
$x->body = substr(stripslashes(str_replace(array("\n","\r")," ", $d[0][content])),0,128) . "...";
$this->results[] = $x;
}
}

return(TRUE);
}


// Index something existing in the document class
function index()
{
if(!$this->document->id)
return(FALSE);

// Delete if this document was previously indexed
$id = $this->document->id;
$exists = $this->db->getsql("SELECT docid FROM ax_search WHERE docid='$id'");
if($exists[0][docid] > 0)
$this->db->getsql("DELETE FROM ax_search WHERE docid='$id'");

// Parse the title and the body
$this->words = array();
$this->parse($this->document->title, $id, 1.5);
$this->parse($this->document->body, $id, 1);

if(count($this->words) > 0)
{
reset($this->words);
while(list($keywordid,$score) = each($this->words))
$this->db->getsql("INSERT INTO ax_search (keywordid, docid, score) VALUES ('$keywordid', '$id', '$score')");
}

return(TRUE);
}


// Parse a document and return its keyword properties
// also kill stopwords, and store the document
function parse($text="", $id=0, $punch=1)
{
$text = str_replace(array("\n", "\r"), " ", strtolower(trim($text)));
$words = preg_split('/\W+/', $text, -1, PREG_SPLIT_NO_EMPTY);
if(count($words) == 0)
return(FALSE);

// Grab the word count
$words = array_count_values($words);

// Store the document
reset($words);
while(list($word,$cnt) = each($words))
{
if($this->stopwords[$word])
continue;

$keywordid = $this->db->get_keyword($word, TRUE);
$c = $cnt * $punch;
$this->words[$keywordid] += $c;
}

return(TRUE);
}

}

// The search document
class document
{
var $id;
var $title;
var $body;
}

?>