XOOPS / XoopsCore

        $pattern     = "/(^|[^]_a-z0-9-=\"'\/])([a-z]+?):\/\/([{$valid_chars}]+[{$end_chars}])/i";

        $text = preg_replace_callback(

            $pattern,

            function ($match) {

                return $match[1] . "<a href=\"$match[2]://$match[3]\" title=\"$match[2]://$match[3]\""

                . "rel=\"external\">$match[2]://".$this->truncate($match[3]).'</a>';

            },

            $text

        );

        $pattern     = "/(^|[^]_a-z0-9-=\"'\/:\.])www\.((([a-zA-Z0-9\-]*\.){1,}){1}([a-zA-Z]{2,6}){1})((\/([a-zA-Z0-9\-\._\?\,\'\/\\+&%\$#\=~])*)*)/i";

        $text = preg_replace_callback(

            $pattern,

            function ($match) {

                return $match[1] ."<a href=\"http://www.$match[2]$match[6]\" "

                . "title=\"www.$match[2]$match[6]\" rel=\"external\">" .

                $this->truncate('www.'.$match[2].$match[6]) .'</a>';

            },

            $text

        );

        $pattern     = "/(^|[^]_a-z0-9-=\"'\/])ftp\.([a-z0-9\-]+)\.([{$valid_chars}]+[{$end_chars}])/i";

        $text = preg_replace_callback(

            $pattern,

            function ($match) {

                return $match[1]."<a href=\"ftp://ftp.$match[2].$match[3]\" "

                . "title=\"ftp.$match[2].$match[3]\" rel=\"external\">"

                . $this->truncate('ftp.'.$match[2].$match[3]) .'</a>';

            },

            $text

        );

        $pattern     = "/(^|[^]_a-z0-9-=\"'\/:\.])([-_a-z0-9\'+*$^&%=~!?{}]++(?:\.[-_a-z0-9\'+*$^&%=~!?{}]+)*+)@((?:(?![-.])[-a-z0-9.]+(?<![-.])\.[a-z]{2,6}|\d{1,3}(?:\.\d{1,3}){3})(?::\d++)?)/i";

        $text = preg_replace_callback(

            $pattern,

            function ($match) {

                return $match[1]. "<a href=\"mailto:$match[2]@$match[3]\" title=\"$match[2]@$match[3]\">"

                . $this->truncate($match[2] . "@" . $match[3]) . '</a>';

            },

            $text

        );