+/**
+ * Decodes a RFC 822 Date-header into a timestamp
+ *
+ * @param array dateParts the Date-header split by whitespace
+ * @return int the timestamp calculated from the header
+ */
+function getTimeStamp($dateParts) {
+ /* $dateParts[0] == <day of week> Mon, Tue, Wed
+ * $dateParts[1] == <day of month> 23
+ * $dateParts[2] == <month> Jan, Feb, Mar
+ * $dateParts[3] == <year> 1999
+ * $dateParts[4] == <time> 18:54:23 (HH:MM:SS)
+ * $dateParts[5] == <from GMT> +0100
+ * $dateParts[6] == <zone> (EDT)
+ *
+ * NOTE: In RFC 822, it states that <day of week> is optional.
+ * In that case, dateParts[0] would be the <day of month>
+ * and everything would be bumped up one.
+ */
+
+ /*
+ * Simply check to see if the first element in the dateParts
+ * array is an integer or not.
+ * Since the day of week is optional, this check is needed.
+ */
+ if (count($dateParts) <2) {
+ return -1;
+ } else if (count($dateParts) ==3) {
+ if (substr_count($dateParts[0],'-') == 2 &&
+ substr_count($dateParts[1],':') == 2) {
+ // dd-Month-yyyy 23:19:05 +0200
+ // redefine the date
+ $aDate = explode('-',$dateParts[0]);
+ $newDate = array($aDate[0],$aDate[1],$aDate[2],$dateParts[1],$dateParts[2]);
+ $dateParts = $newDate;
+ }
+ }
+
+ /* remove day of week */
+ if (!is_numeric(trim($dateParts[0]))) {
+ $dataParts = array_shift($dateParts);
+ }
+ /* calculate timestamp separated from the zone and obs-zone */
+ $stamp = strtotime(implode (' ', array_splice ($dateParts,0,4)));
+ if (!isset($dateParts[0])) {
+ $dateParts[0] = '+0000';
+ }
+
+ if (!preg_match('/^[+-]{1}[0-9]{4}$/',$dateParts[0])) {
+ /* zone in obs-zone format */
+ if (preg_match('/\((.+)\)/',$dateParts[0],$regs)) {
+ $obs_zone = $regs[1];
+ } else {
+ $obs_zone = $dateParts[0];
+ }
+ return getGMTSeconds($stamp, $obs_zone);
+ } else {
+ return getGMTSeconds($stamp, $dateParts[0]);
+ }
+}