dedecms如何增加和调用自定义函数

//通过会员ID调用会员uname名称的函数 
function GetMemberName($str){ 
global $dsql; 
$row = $dsql->GetOne("SELECT uname FROM `dede_member` WHERE mid = '$str' "); 
return $row[uname]; 
}

//通过栏目ID号获取栏目保存目录
function GetTypeUrl($tid)
{
 global $dsql;
 global $cfg_cmspath;
 $query ="select typedir from `dede_arctype` where id=$tid";
 if($row=$dsql->getone($query))
 {
  $temp=str_replace("{cmspath}",$cfg_cmspath,$row['typedir']).'/';
 }
 return $temp;
}

//通过文档ID获取文档静态url地址
if(!function_exists('GetArcUrl'))
 { 
function GetArcUrl($id)
 {
 global $dsql; 
$arcRow = $dsql->GetOne("SELECT * FROM dede_archives WHERE `id` = '{$id}'"); 
$typeRow = $dsql->GetOne("SELECT * FROM dede_arctype WHERE `id` = '{$arcRow['typeid']}'"); 
$arcurl = GetFileUrl($id,$arcRow['typeid'],$arcRow['senddate'],$arcRow['title'],$arcRow['ismake'], $arcRow['arcrank'],$typeRow['namerule'],$typeRow['typedir'] ,$arcRow['money'],$arcRow['filename'],$typeRow['moresite'],$typeRow['siteurl'], $typeRow['sitepath']); return $arcurl; 
 } 
}