<?php
/*
 * Project:     MagpieRSS: a simple RSS integration tool
 * File:        rss_utils.inc, utility methods for working with RSS
 * Author:      Kellan Elliott-McCrea <kellan@protest.net>
 * Version:		0.51
 * License:		GPL
 *
 * The lastest version of MagpieRSS can be obtained from:
 * http://magpierss.sourceforge.net
 *
 * For questions, help, comments, discussion, etc., please join the
 * Magpie mailing list:
 * magpierss-general@lists.sourceforge.net
 */

/*======================================================================*\
    Function: parse_w3cdtf
    Purpose:  parse a W3CDTF date into unix epoch

	NOTE: http://www.w3.org/TR/NOTE-datetime
\*======================================================================*/

function parse_w3cdtf ($date_str)
{ 
    // regex to match wc3dtf
    $pat = "/(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2})(:(\d{2}))?(?:([-+])(\d{2}):?(\d{2})|(Z))?/";

    if (preg_match($pat, $date_str, $match)) {
        list($year, $month, $day, $hours, $minutes, $seconds) =
        array($match[1], $match[2], $match[3], $match[4], $match[5], $match[6]); 
        // calc epoch for current date assuming GMT
        $epoch = gmmktime($hours, $minutes, $seconds, $month, $day, $year);

        $offset = 0;
        if ($match[10] == 'Z') {
            // zulu time, aka GMT
        } else {
            list($tz_mod, $tz_hour, $tz_min) =
            array($match[8], $match[9], $match[10]); 
            // zero out the variables
            if (! $tz_hour) {
                $tz_hour = 0;
            } 
            if (! $tz_min) {
                $tz_min = 0;
            } 

            $offset_secs = (($tz_hour * 60) + $tz_min) * 60; 
            // is timezone ahead of GMT?  then subtract offset
            
            if ($tz_mod == '+') {
                $offset_secs = $offset_secs * -1;
            } 

            $offset = $offset_secs;
        } 
        $epoch = $epoch + $offset;
        return $epoch;
    } else {
        return -1;
    } 
} 

?>