Converts any url in string to a html http link tag

linkify.php

<?php
function linkify($string)
{
    $reg_exUrl = "@(https://|http://|www)[^<>[:space:]]+[[:alnum:]/]@";
    $links = array();
    preg_match_all($reg_exUrl, $string, $urls);
    foreach ($urls[0] as $url) {

        $string = str_replace($url, "[[:link:".(count($links)).":]]" , $string);
        $force_http = "";
        if( strpos($url, "http://") === false && strpos($url, "https://") === false ){
            $force_http = "http://";
        }
        array_push($links, "<a target='_blank' href='{$force_http}{$url}'>{$url}</a>");
    }
    for($i =0; $i< count($links); $i++){
        $string = str_replace("[[:link:".($i).":]]", $links[$i], $string);
    }
    return $string;
}
?>