/system/core/compat/standard.php

<?php
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2019 - 2022, 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	EllisLab Dev Team
 * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
 * @copyright	Copyright (c) 2014 - 2019, British Columbia Institute of Technology (https://bcit.ca/)
 * @copyright	Copyright (c) 2019 - 2022, CodeIgniter Foundation (https://codeigniter.com/)
 * @license	https://opensource.org/licenses/MIT	MIT License
 * @link	https://codeigniter.com
 * @since	Version 3.0.0
 * @filesource
 */
defined('BASEPATH') OR exit('No direct script access allowed');

/**
 * PHP ext/standard compatibility package
 *
 * @package		CodeIgniter
 * @subpackage	CodeIgniter
 * @category	Compatibility
 * @author		Andrey Andreev
 * @link		https://codeigniter.com/userguide3/
 */

// ------------------------------------------------------------------------

if (is_php('5.5'))
{
	return;
}

// ------------------------------------------------------------------------

if ( ! function_exists('array_column'))
{
	/**
	 * array_column()
	 *
	 * @link	http://php.net/array_column
	 * @param	array	$array
	 * @param	mixed	$column_key
	 * @param	mixed	$index_key
	 * @return	array
	 */
	function array_column(array $array, $column_key, $index_key = NULL)
	{
		if ( ! in_array($type = gettype($column_key), array('integer', 'string', 'NULL'), TRUE))
		{
			if ($type === 'double')
			{
				$column_key = (int) $column_key;
			}
			elseif ($type === 'object' && method_exists($column_key, '__toString'))
			{
				$column_key = (string) $column_key;
			}
			else
			{
				trigger_error('array_column(): The column key should be either a string or an integer', E_USER_WARNING);
				return FALSE;
			}
		}

		if ( ! in_array($type = gettype($index_key), array('integer', 'string', 'NULL'), TRUE))
		{
			if ($type === 'double')
			{
				$index_key = (int) $index_key;
			}
			elseif ($type === 'object' && method_exists($index_key, '__toString'))
			{
				$index_key = (string) $index_key;
			}
			else
			{
				trigger_error('array_column(): The index key should be either a string or an integer', E_USER_WARNING);
				return FALSE;
			}
		}

		$result = array();
		foreach ($array as &$a)
		{
			if ($column_key === NULL)
			{
				$value = $a;
			}
			elseif (is_array($a) && array_key_exists($column_key, $a))
			{
				$value = $a[$column_key];
			}
			else
			{
				continue;
			}

			if ($index_key === NULL OR ! array_key_exists($index_key, $a))
			{
				$result[] = $value;
			}
			else
			{
				$result[$a[$index_key]] = $value;
			}
		}

		return $result;
	}
}

// ------------------------------------------------------------------------

if (is_php('5.4'))
{
	return;
}

// ------------------------------------------------------------------------

if ( ! function_exists('hex2bin'))
{
	/**
	 * hex2bin()
	 *
	 * @link	http://php.net/hex2bin
	 * @param	string	$data
	 * @return	string
	 */
	function hex2bin($data)
	{
		if (in_array($type = gettype($data), array('array', 'double', 'object', 'resource'), TRUE))
		{
			if ($type === 'object' && method_exists($data, '__toString'))
			{
				$data = (string) $data;
			}
			else
			{
				trigger_error('hex2bin() expects parameter 1 to be string, '.$type.' given', E_USER_WARNING);
				return NULL;
			}
		}

		if (strlen($data) % 2 !== 0)
		{
			trigger_error('Hexadecimal input string must have an even length', E_USER_WARNING);
			return FALSE;
		}
		elseif ( ! preg_match('/^[0-9a-f]*$/i', $data))
		{
			trigger_error('Input string must be hexadecimal string', E_USER_WARNING);
			return FALSE;
		}

		return pack('H*', $data);
	}
}