/**
* Converts Unix timestamp to historic date timestamp
*
* @param int $pn_timestamp A Unix-format timestamp
* @return float Equivalent value as floating point historic timestamp value, or null if Unix timestamp was not valid.
*/
function caUnixTimestampToHistoricTimestamps($pn_timestamp)
{
$o_tep = new TimeExpressionParser();
return $o_tep->unixToHistoricTimestamp($pn_timestamp);
}
