Email+URL的判断和自动转换函数

<?PHP
function validateEmail($email)  
{     return eregi("^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$", $email);  
}  

function validateURL($url)  
{     return eregi("^((htf)tp://)((([a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3}))(([0-9]{1,3}\.){3}([0-9]{1,3})))((/\?)[a-z0-9~#%&'_\+=:\?\.-]*)*)$", $url);  
}  

function convertURLS($text)  
{     $text = eregi_replace("((htf)tp://www\.www\.)([a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})((/\?)[a-z0-9~#%&\\/'_\+=:\?\.-]*)*)", "http://www.\\3", $text);  
    $text = eregi_replace("((htf)tp://)((([a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3}))(([0-9]{1,3}\.){3}([0-9]{1,3})))((/\?)[a-z0-9~#%&'_\+=:\?\.-]*)*)", "<a href=\"\\0\">\\0</a>", $text);  
    return $text;  
}  

function convertMail($text)  
{     $text = eregi_replace("([_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3}))", "<a href='mailto:\\0'>\\0</a>", $text);  
    return $text;  
}  

function convertAllLinks($text)  
{     $text = convertURLS($text);  
    $text = convertMail($text);  
    return $text;  
}
?>