Как убрать внешние ссылки вида http://...

    function insert_smiles($text) {
        $text = nl2br(htmlspecialchars($text,ENT_NOQUOTES));
        $text = str_replace('  ', '  ', $text);
        $search = array(
                "'(.)((http|https|ftp)://[\w\d-]+\.[\w\d-]+[^\s<\"\']*[^.,;\s<\"\'\)]+)'si",
                "'([^/])(www\.[\w\d-]+\.[\w\d-]+[^\s<\"\']*[^.,;\s<\"\'\)]+)'si",
                "'([^\w\d-\.])([\w\d-\.]+@[\w\d-\.]+\.[\w]+[^.,;\s<\"\'\)]+)'si"
            );
        $replace = array(
                '$1<a href="$2" target="_blank">$2</a>',
                '$1<a href="http://$2" target="_blank">$2</a>',
                '$1<a href="mailto:$2">$2</a>'
            );
        $text = preg_replace($search, $replace, $text);
        foreach ($this -> mnemonics as $mnemonic => $value) {
            $text = str_replace($mnemonic, $value, $text);
        }
        return $text;
    }

    function insert_smiles($text) {
        $text = nl2br(htmlspecialchars($text,ENT_NOQUOTES));
        $text = str_replace('  ', '  ', $text);
        $search = array(
                /*"'(.)((http|https|ftp)://[\w\d-]+\.[\w\d-]+[^\s<\"\']*[^.,;\s<\"\'\)]+)'si",
                "'([^/])(www\.[\w\d-]+\.[\w\d-]+[^\s<\"\']*[^.,;\s<\"\'\)]+)'si",*/
                "'([^\w\d-\.])([\w\d-\.]+@[\w\d-\.]+\.[\w]+[^.,;\s<\"\'\)]+)'si"
            );
        $replace = array(
                /*'$1<a href="$2" target="_blank">$2</a>',
                '$1<a href="http://$2" target="_blank">$2</a>',*/
                '$1<a href="mailto:$2">$2</a>'
            );
        $text = preg_replace($search, $replace, $text);
        foreach ($this -> mnemonics as $mnemonic => $value) {
            $text = str_replace($mnemonic, $value, $text);
        }
        return $text;
    }