XML parse file with highlight link

bumbar

I have very simple XML Parser.

<?php
$file = "xml_beginner.xml";

function contents($parser, $data){
echo $data;
}

function startTag($parser, $data){
echo "<b>";
}

function endTag($parser, $data){
echo "</b><br />";
}

$xml_parser = xml_parser_create();

xml_set_element_handler($xml_parser, "startTag", "endTag");

xml_set_character_data_handler($xml_parser, "contents");

$fp = fopen($file, "r");

$data = fread($fp, 80000);

if(!(xml_parse($xml_parser, $data, feof($fp)))){
die("Error on line " . xml_get_current_line_number($xml_parser));
}

xml_parser_free($xml_parser);

fclose($fp);

My quest: can I get $data (content file) and manipulate $data before output parsing? I want use $output = preg_replace("^{[a-zA_Z]{3}.[a-zA-Z.-]{1,100}.(html|com|net|org|info|biz|eu|name|us|co.uk|org.uk|bg|de|fr)^",} "<a href=\"$0\">$0</a>", $data); to highlight url link in content.

thanks!