Detekce hypertextového odkazu

function make_clickable($text)
  {
   $text = preg_replace('#(script|about|applet|activex|chrome):#is', "\\1:", $text);

   // pridame mezeru aby sel porovnavat text na zacatku prvniho radku
   $ret = ' ' . $text;

   // najde "xxxx://yyyy" URL na zacatku radku nebo za mezerou
   // xxxx mohou byt jen alfa znaky
   // yyyy je cokoliv az k prvni mezere, odradkovani, carce, uvozovce nebo mene nez
   $ret = preg_replace("#(^|[\n ])([\w]+?://[\w\#$%&~/.\-;:=,?@\[\]+]*)#is", "\\1<a href=\"\\2\" target=\"_blank\">\\2</a>", $ret);

   // najde "www|ftp.xxxx.yyyy[/zzzz]" url
   // musi obsahovat alespon dve tecky...xxxx obsahuje alfanumericke znaky nebo -
   // zzzz je volitelne..opet cokoliv az k prvni mezere, odradkovani, carce, uvozovce nebo mene nez
   $ret = preg_replace("#(^|[\n ])((www|ftp)\.[\w\#$%&~/.\-;:=,?@\[\]+]*)#is", "\\1<a href=\"http://\\2\" target=\"_blank\">\\2</a>", $ret);

   // najde email@domena adresu na zacatku radku nebo po mezere
   // platne znaky; alfanumericke, "-", "_" a,nebo ".".
   $ret = preg_replace("#(^|[\n ])([a-z0-9&\-_.]+?)@([\w\-]+\.([\w\-\.]+\.)*[\w]+)#i", "\\1<a href=\"mailto:\\2@\\3\">\\2@\\3</a>", $ret);

   // odstranit mezeru na zacatku..
   $ret = substr($ret, 1);

   return($ret);
  }

function make_clickable($text){
    // match protocol://address/path/
    $text = preg_replace_callback("#(^| |\n)([a-zA-Z]+://)([.]?[?=&a-zA-Z0-9_/-])*#", create_function('$part',
                            '$text_link = (strlen($part[0]) > 19) ? substr($part[0],0,14) . "..." . substr($part[0],-2) : $part[0];
                            return $part[1] . "<a href=\"{$part[0]}\" title=\"Odkaz: {$part[0]}\" target=\"_blank\">{$text_link}</a>";')
                            , $text);

    // match http://www.something
    //added |\n so catches new lines as well and not links in the [url=...] tags or in quotes
    $text = preg_replace_callback("#(^| |\n)(www([.]?[?=&a-zA-Z0-9_/-])*)#", create_function('$part',
                            '$text_link = (strlen($part[2]) > 15) ? substr($part[2],0,10) . "..." . substr($part[2],-2) : $part[2];
                            return $part[1] . "<a href=\"http://{$part[2]}\" title=\"Odkaz: http://{$part[2]}\"; target=\"_blank\">{$text_link}</a>";')
                            , $text);

    // return $text
    return $text;
    }