combined ids

combined-ids.php

<?php

function compositeId($calendarId, \DateTime $start) {
  static $startOfTime = 1410963347;
  $time = ($start->getTimestamp() - $startOfTime) / 60 / 5;
  if ($time & 0xFFFF0000) {
    throw new RuntimeException(sprintf('We have ran out of time: %s!', $start->format('Y-m-d H:i:s')));
  }
  if ($calendarId & 0xFFFF0000) {
    throw new RuntimeException(sprintf('We are too successful (calendarId: %d)', $calendarId));
  }
  
  return $time + ($calendar << 16);
}
function reverseCompositeId($compositeId) {
  static $startOfTime = 1410963347;
  return [
    $compositeId >> 16,
    DateTime::createFromFormat('U', ($compositeId & 0xFFFF) * 60 * 5 + $startOfTime),
  ];
}