这段ASP查找替换代码,该如何用PHP改写呢？谢谢，急

$betw = strpos($SourceCode,"<TABLE bgColor=#e6e6e6 border=0 cellPadding=0 cellSpacing=0 width=100") - strpos($SourceCode,"<tr><td align=right><font class=c size=\"-1\">到<a href=\"http://forum.baidu.com/cgi-bin/forum/board_show.cgi?id=1&age=60\">搜索援助中心</a>");$first=strpos($SourceCode,"<TABLE bgColor=#e6e6e6 border=0 cellPadding=0 cellSpacing=0 width=100");$SourceCode = substr($SourceCode,$first,$betw);$SourceCode = str_replace ("/baidu?","search.asp?",$SourceCode);$tt1 = explode("<ol>",$SourceCode);