*/ class SplPriorityQueue extends \SplPriorityQueue implements Serializable { /** @var int Seed used to ensure queue order for items of the same priority */ protected $serial = PHP_INT_MAX; /** * Insert a value with a given priority * * Utilizes {@var $serial} to ensure that values of equal priority are * emitted in the same order in which they are inserted. * * @param TValue $datum * @param TPriority $priority * @return void */ public function insert($datum, $priority) { if (! is_array($priority)) { $priority = [$priority, $this->serial--]; } parent::insert($datum, $priority); } /** * Serialize to an array * * Array will be priority => data pairs * * @return list */ public function toArray() { $array = []; foreach (clone $this as $item) { $array[] = $item; } return $array; } /** * Serialize * * @return string */ public function serialize() { return serialize($this->__serialize()); } /** * Magic method used for serializing of an instance. * * @return array */ public function __serialize() { $clone = clone $this; $clone->setExtractFlags(self::EXTR_BOTH); $data = []; foreach ($clone as $item) { $data[] = $item; } return $data; } /** * Deserialize * * @param string $data * @return void */ public function unserialize($data) { $toUnserialize = unserialize($data); if (! is_array($toUnserialize)) { throw new UnexpectedValueException(sprintf( 'Cannot deserialize %s instance; corrupt serialization data', self::class )); } $this->__unserialize($toUnserialize); } /** * Magic method used to rebuild an instance. * * @param array $data Data array. * @return void */ public function __unserialize($data) { $this->serial = PHP_INT_MAX; foreach ($data as $item) { if (! is_array($item)) { throw new UnexpectedValueException(sprintf( 'Cannot deserialize %s instance: corrupt item; expected array, received %s', self::class, is_object($item) ? get_class($item) : gettype($item) )); } if (! array_key_exists('data', $item)) { throw new UnexpectedValueException(sprintf( 'Cannot deserialize %s instance: corrupt item; missing "data" element', self::class )); } $priority = 1; if (array_key_exists('priority', $item)) { $priority = (int) $item['priority']; } $this->insert($item['data'], $priority); } } }