<?php
 
function MontarLink($texto)
{
       if (!is_string ($texto))
           return $texto;
 
    $er = "/(https:\/\/(www\.|.*?\/)?|http:\/\/(www\.|.*?\/)?|www\.)([a-zA-Z0-9]+|_|-)+(\.(([0-9a-zA-Z]|-|_|\/|\?|=|&)+))+/i";
 
    preg_match_all ($er, $texto, $match);
 
    foreach ($match[0] as $link)
    {
 
        //coloca o 'http://' caso o link não o possua
        $link_completo = (stristr($link, "http") === false) ? "http://" . $link : $link;
 
        $link_len = strlen ($link);
 
        //troca "&" por "&", tornando o link válido pela W3C
       $web_link = str_replace ("&", "&amp;", $link_completo);
       $texto = str_ireplace ($link, "<a href=\"" . strtolower($web_link) . "\" target=\"_blank\">". (($link_len > 60) ? substr ($web_link, 0, 25). "...". substr ($web_link, -15) : $web_link) ."</a>", $texto);
 
    }
 
    return $texto;
 
}
 
echo MontarLink("ola mundo www.cade.com.br bla bla www.foo.com");

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