UBB代码处理函数(PHP)

本人对正则表达式不熟，不会写UBB的转换函数，后来在网上下载了一个程序，在其代码里找到了这个函数，并且运行成功，特贴出来共享一下:

function UBB2html($SourceStr){//UBB代码处理函数！目前只想支持<img><a>和mailto

 $targetstr=str_replace(array("[b]","[/b]","[u]","[/u]","[i]","[/i]"),array("","","","","",""),$SourceStr); //
 $ubbcodes['searcharray'] = array(
 "/\[url=(https?|ftp|gopher|news|telnet|mms|rtsp)([^\[]*)\](.+?)\[\/url\]/eis",
 "/\[url\]www\.([^\[]*)\[\/url\]/eis",
 "/\[url\](https?|ftp|gopher|news|telnet|mms|rtsp)([^\[]*)\[\/url\]/eis",
 "/\[email\]\s*([a-z0-9\-_.+]+)@([a-z0-9\-_]+[.][a-z0-9\-_.]+)\s*\[\/email\]/i",
 "/\[email=([a-z0-9\-_.+]+)@([a-z0-9\-_]+[.][a-z0-9\-_.]+)\](.+?)\[\/email\]/is",
 "/\[img\](.+?)\[\/img\]/is"
 );
 $ubbcodes['replacearray'] = array(
 "cvurl('\\1','\\2','\\3')",
 "cvurl('\\1')",
 "cvurl('\\1','\\2')",
 "<a href=\"mailto:\\1@\\2\">\\1@\\2</a>",
 "<a href=\"mailto:\\1@\\2\">\\3</a>",
 "<a href=\"\\1\" target=\"_blank\" title=\"点击查看大图\"><img src=\"\\1\" height=\"100\" border=\"0\"></a>"
 );
 return preg_replace($ubbcodes['searcharray'],$ubbcodes['replacearray'],$targetstr);

}