text: <?php
  
  /**
   * CodeIgniter
   *
   * An open source application development framework for PHP
   *
   * This content is released under the MIT License (MIT)
   *
   * Copyright (c) 2014-2017 British Columbia Institute of Technology
   * Copyright (c) 2019-2020 CodeIgniter Foundation
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   * THE SOFTWARE.
   *
   * @package    CodeIgniter
   * @author     CodeIgniter Dev Team
   * @copyright  2014-2017 British Columbia Institute of Technology (https://bcit.ca/)
   * @license    https://opensource.org/licenses/MIT	MIT License
   * @link       https://codeigniter.com
   * @since      Version 4.0.0
   * @filesource
   */
  
  namespace CodeIgniter\Encryption\Handlers;
  
  use CodeIgniter\Config\BaseConfig;
  use CodeIgniter\Encryption\EncrypterInterface;
  
  /**
   * Base class for encryption handling
   */
  abstract class BaseHandler implements EncrypterInterface
  {
  	/**
  	 * Logger instance to record error messages and warnings.
  	 *
  	 * @var \Psr\Log\LoggerInterface
  	 */
  	protected $logger;
  
  	//--------------------------------------------------------------------
  
  	/**
  	 * Constructor
  	 *
  	 * @param \CodeIgniter\Config\BaseConfig|null $config
  	 */
  	public function __construct(BaseConfig $config = null)
  	{
  		$config = $config ?? new \Config\Encryption();
  
  		// make the parameters conveniently accessible
  		foreach ($config as $pkey => $value) // @phpstan-ignore-line
  		{
  			$this->$pkey = $value;
  		}
  	}
  
  	/**
  	 * Byte-safe substr()
  	 *
  	 * @param  string  $str
  	 * @param  integer $start
  	 * @param  integer $length
  	 * @return string
  	 */
  	protected static function substr($str, $start, $length = null)
  	{
  		return mb_substr($str, $start, $length, '8bit');
  	}
  
  	/**
  	 * __get() magic, providing readonly access to some of our properties
  	 *
  	 * @param  string $key Property name
  	 * @return mixed
  	 */
  	public function __get($key)
  	{
  		if (in_array($key, ['cipher', 'key'], true))
  		{
  			return $this->{$key};
  		}
  
  		return null;
  	}
  
  	/**
  	 * __isset() magic, providing checking for some of our properties
  	 *
  	 * @param  string $key Property name
  	 * @return boolean
  	 */
  	public function __isset($key): bool
  	{
  		return in_array($key, ['cipher', 'key'], true);
  	}
  }
  