Convert RFC1123-style time differences to N-seconds (PHP)

td2sec.php

/**                                                                             
 * Convert RFC1123-style time differences to N-seconds                          
 *                                                                
 * If unixtime is given, convert first it to RFC1123-style time                 
 * differences by date( "O" ).                                                  
 *                                                                              
 * @since  2008-10-03                                                           
 * @param  string                                                               
 * @return int                                                                  
 */
function td2sec( $str ) {
  if ( preg_match( '/\A[0-9]+\z/', $str ) > 0 ) {
    $str = date( "O", $str );
  }

  if ( preg_match( '/\A([+-])([0-9]{2})([0-9]{2})\z/', $str, $match ) > 0 ) {
    return sprintf( "%s%d",
                     $match[1], 
                     (int)$match[2] * 3600 + (int)$match[3] * 60 );
  }
}