OneLogin_Saml2_Utils::parseDuration PHP Method

    public static function parseDuration($duration, $timestamp = null)
    {
        assert('is_string($duration)');
        assert('is_null($timestamp) || is_int($timestamp)');
        /* Parse the duration. We use a very strict pattern. */
        $durationRegEx = '#^(-?)P(?:(?:(?:(\\d+)Y)?(?:(\\d+)M)?(?:(\\d+)D)?(?:T(?:(\\d+)H)?(?:(\\d+)M)?(?:(\\d+)S)?)?)|(?:(\\d+)W))$#D';
        if (!preg_match($durationRegEx, $duration, $matches)) {
            throw new Exception('Invalid ISO 8601 duration: ' . $duration);
        }
        $durYears = empty($matches[2]) ? 0 : (int) $matches[2];
        $durMonths = empty($matches[3]) ? 0 : (int) $matches[3];
        $durDays = empty($matches[4]) ? 0 : (int) $matches[4];
        $durHours = empty($matches[5]) ? 0 : (int) $matches[5];
        $durMinutes = empty($matches[6]) ? 0 : (int) $matches[6];
        $durSeconds = empty($matches[7]) ? 0 : (int) $matches[7];
        $durWeeks = empty($matches[8]) ? 0 : (int) $matches[8];
        if (!empty($matches[1])) {
            /* Negative */
            $durYears = -$durYears;
            $durMonths = -$durMonths;
            $durDays = -$durDays;
            $durHours = -$durHours;
            $durMinutes = -$durMinutes;
            $durSeconds = -$durSeconds;
            $durWeeks = -$durWeeks;
        }
        if ($timestamp === null) {
            $timestamp = time();
        }
        if ($durYears !== 0 || $durMonths !== 0) {
            /* Special handling of months and years, since they aren't a specific interval, but
             * instead depend on the current time.
             */
            /* We need the year and month from the timestamp. Unfortunately, PHP doesn't have the
             * gmtime function. Instead we use the gmdate function, and split the result.
             */
            $yearmonth = explode(':', gmdate('Y:n', $timestamp));
            $year = (int) $yearmonth[0];
            $month = (int) $yearmonth[1];
            /* Remove the year and month from the timestamp. */
            $timestamp -= gmmktime(0, 0, 0, $month, 1, $year);
            /* Add years and months, and normalize the numbers afterwards. */
            $year += $durYears;
            $month += $durMonths;
            while ($month > 12) {
                $year += 1;
                $month -= 12;
            }
            while ($month < 1) {
                $year -= 1;
                $month += 12;
            }
            /* Add year and month back into timestamp. */
            $timestamp += gmmktime(0, 0, 0, $month, 1, $year);
        }
        /* Add the other elements. */
        $timestamp += $durWeeks * 7 * 24 * 60 * 60;
        $timestamp += $durDays * 24 * 60 * 60;
        $timestamp += $durHours * 60 * 60;
        $timestamp += $durMinutes * 60;
        $timestamp += $durSeconds;
        return $timestamp;
    }

 /**
  * Tests the parseDuration method of the OneLogin_Saml2_Utils
  *
  * @covers OneLogin_Saml2_Utils::parseDuration
  */
 public function testParseDuration()
 {
     $duration = 'PT1393462294S';
     $timestamp = 1393876825;
     $parsedDuration = OneLogin_Saml2_Utils::parseDuration($duration, $timestamp);
     $this->assertEquals(2787339119, $parsedDuration);
     $parsedDuration2 = OneLogin_Saml2_Utils::parseDuration($duration);
     $this->assertTrue($parsedDuration2 > $parsedDuration);
     $invalidDuration = 'PT1Y';
     try {
         $parsedDuration3 = OneLogin_Saml2_Utils::parseDuration($invalidDuration);
         $this->assertFalse(true);
     } catch (Exception $e) {
         $this->assertContains('Invalid ISO 8601 duration', $e->getMessage());
     }
     $newDuration = 'P1Y1M';
     $parsedDuration4 = OneLogin_Saml2_Utils::parseDuration($newDuration, $timestamp);
     $this->assertEquals(1428091225, $parsedDuration4);
     $negDuration = '-P14M';
     $parsedDuration5 = OneLogin_Saml2_Utils::parseDuration($negDuration, $timestamp);
     $this->assertEquals(1357243225, $parsedDuration5);
 }