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   1  <?php
   2  /**
   3   * Zend Framework (http://framework.zend.com/)
   4   *
   5   * @link      http://github.com/zendframework/zf2 for the canonical source repository
   6   * @copyright Copyright (c) 2005-2015 Zend Technologies USA Inc. (http://www.zend.com)
   7   * @license   http://framework.zend.com/license/new-bsd New BSD License
   8   */
   9  
  10  namespace Zend\Stdlib;
  11  
  12  use Serializable;
  13  
  14  /**
  15   * Serializable version of SplPriorityQueue
  16   *
  17   * Also, provides predictable heap order for datums added with the same priority
  18   * (i.e., they will be emitted in the same order they are enqueued).
  19   */
  20  class SplPriorityQueue extends \SplPriorityQueue implements Serializable
  21  {
  22      /**
  23       * @var int Seed used to ensure queue order for items of the same priority
  24       */
  25      protected $serial = PHP_INT_MAX;
  26  
  27      /**
  28       * Insert a value with a given priority
  29       *
  30       * Utilizes {@var $serial} to ensure that values of equal priority are
  31       * emitted in the same order in which they are inserted.
  32       *
  33       * @param  mixed $datum
  34       * @param  mixed $priority
  35       * @return void
  36       */
  37      public function insert($datum, $priority)
  38      {
  39          if (!is_array($priority)) {
  40              $priority = array($priority, $this->serial--);
  41          }
  42          parent::insert($datum, $priority);
  43      }
  44  
  45      /**
  46       * Serialize to an array
  47       *
  48       * Array will be priority => data pairs
  49       *
  50       * @return array
  51       */
  52      public function toArray()
  53      {
  54          $array = array();
  55          foreach (clone $this as $item) {
  56              $array[] = $item;
  57          }
  58          return $array;
  59      }
  60  
  61      /**
  62       * Serialize
  63       *
  64       * @return string
  65       */
  66      public function serialize()
  67      {
  68          $clone = clone $this;
  69          $clone->setExtractFlags(self::EXTR_BOTH);
  70  
  71          $data = array();
  72          foreach ($clone as $item) {
  73              $data[] = $item;
  74          }
  75  
  76          return serialize($data);
  77      }
  78  
  79      /**
  80       * Deserialize
  81       *
  82       * @param  string $data
  83       * @return void
  84       */
  85      public function unserialize($data)
  86      {
  87          foreach (unserialize($data) as $item) {
  88              $this->insert($item['data'], $item['priority']);
  89          }
  90      }
  91  }