.. include:: ../../Includes.txt

========================================
Feature: #87665 - Introduce BitSet class
========================================

See :issue:`87665`

Description
===========

To efficiently handle boolean flags, bit sets can be used. Therefore a new class :php:`\TYPO3\CMS\Core\Type\BitSet` has been introduced.
The bit set can be used standalone and accessed from the outside but it can also be used to create specific BitSet classes that extend the BitSet class.

The functionality is best described by an example:

::

   <?php
   declare(strict_types = 1);

   define('PERMISSIONS_NONE', 0b0); // 0
   define('PERMISSIONS_PAGE_SHOW', 0b1); // 1
   define('PERMISSIONS_PAGE_EDIT', 0b10); // 2
   define('PERMISSIONS_PAGE_DELETE', 0b100); // 4
   define('PERMISSIONS_PAGE_NEW', 0b1000); // 8
   define('PERMISSIONS_CONTENT_EDIT', 0b10000); // 16
   define('PERMISSIONS_ALL', 0b11111); // 31

   $bitSet = new \TYPO3\CMS\Core\Type\BitSet(PERMISSIONS_PAGE_SHOW | PERMISSIONS_PAGE_NEW);
   $bitSet->get(PERMISSIONS_PAGE_SHOW); // true
   $bitSet->get(PERMISSIONS_CONTENT_EDIT); // false

Another example shows how to possibly extend the :php:`\TYPO3\CMS\Core\Type\BitSet` class.

::

   <?php
   declare(strict_types = 1);

   class Permissions extends \TYPO3\CMS\Core\Type\BitSet
   {
       public const NONE = 0b0; // 0
       public const PAGE_SHOW = 0b1; // 1
       public const PAGE_EDIT = 0b10; // 2
       public const PAGE_DELETE = 0b100; // 4
       public const PAGE_NEW = 0b1000; // 8
       public const CONTENT_EDIT = 0b10000; // 16
       public const ALL = 0b11111; // 31

       /**
        * @param int $permission
        * @return bool
        */
       public function hasPermission(int $permission): bool
       {
           return $this->get($permission);
       }

       /**
        * @return bool
        */
       public function hasAllPermissions(): bool
       {
           return $this->get(static::ALL);
       }

       /**
        * @param int $permission
        */
       public function allow(int $permission): void
       {
           $this->set($permission);
       }
   }

   $permissions = new Permissions(Permissions::PAGE_SHOW | Permissions::PAGE_NEW);
   $permissions->hasPermission(Permissions::PAGE_SHOW); // true
   $permissions->hasPermission(Permissions::CONTENT_EDIT); // false


Impact
======

This class may come in handy in all situations where boolean flags need to be managed in an efficient way.

.. index:: PHP-API, ext:core
