+ * Compute eastern for selected year
+ *
+ * @param string $year The eastern year
+ *
+ * @return DateTime The eastern date
+ */
+ public function getEastern(string $year): \DateTime {
+ //Set static results
+ static $results = [];
+
+ //Check if already computed
+ if (isset($results[$year])) {
+ //Return computed eastern
+ return $results[$year];
+ }
+
+ $d = (19 * ($year % 19) + 24) % 30;
+
+ $e = (2 * ($year % 4) + 4 * ($year % 7) + 6 * $d + 5) % 7;
+
+ $day = 22 + $d + $e;
+
+ $month = 3;
+
+ if ($day > 31) {
+ $day = $d + $e - 9;
+ $month = 4;
+ } elseif ($d == 29 && $e == 6) {
+ $day = 10;
+ $month = 4;
+ } elseif ($d == 28 && $e == 6) {
+ $day = 18;
+ $month = 4;
+ }
+
+ //Store eastern in data
+ return ($results[$year] = new \DateTime(sprintf('%04d-%02d-%02d', $year, $month, $day)));
+ }
+
+ /**
+ * Gets number formatter instance matching locale and style.