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<?php

/**

 * CodeIgniter

 *

 * An open source application development framework for PHP

 *

 * This content is released under the MIT License (MIT)

 *

 * Copyright (c) 2014 - 2016, British Columbia Institute of Technology

 *

 * 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 - 2016, British Columbia Institute of Technology (http://bcit.ca/)

 * @license	http://opensource.org/licenses/MIT	MIT License

 * @link	https://codeigniter.com

 * @since	Version 1.0.0

 * @filesource

 */

defined('BASEPATH') OR exit('No direct script access allowed');

/**

 * Common Functions

 *

 * Loads the base classes and executes the request.

 *

 * @package		CodeIgniter

 * @subpackage	CodeIgniter

 * @category	Common Functions

 * @author		EllisLab Dev Team

 * @link		https://codeigniter.com/user_guide/

 */

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

if ( ! function_exists('is_php'))

{

	/**

	 * Determines if the current version of PHP is equal to or greater than the supplied value

	 *

	 * @param	string

	 * @return	bool	TRUE if the current version is $version or higher

	 */

	function is_php($version)

	{

		static $_is_php;

		$version = (string) $version;

		if ( ! isset($_is_php[$version]))

		{

			$_is_php[$version] = version_compare(PHP_VERSION, $version, '>=');

		}

		return $_is_php[$version];

	}

}

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

if ( ! function_exists('is_really_writable'))

{

	/**

	 * Tests for file writability

	 *

	 * is_writable() returns TRUE on Windows servers when you really can't write to

	 * the file, based on the read-only attribute. is_writable() is also unreliable

	 * on Unix servers if safe_mode is on.

	 *

	 * @link	https://bugs.php.net/bug.php?id=54709

	 * @param	string

	 * @return	bool

	 */

	function is_really_writable($file)

	{

		// If we're on a Unix server with safe_mode off we call is_writable

		if (DIRECTORY_SEPARATOR === '/' && (is_php('5.4') OR ! ini_get('safe_mode')))

		{

			return is_writable($file);

		}

		/* For Windows servers and safe_mode "on" installations we'll actually

		 * write a file then read it. Bah...

		 */

		if (is_dir($file))

		{

			$file = rtrim($file, '/').'/'.md5(mt_rand());

			if (($fp = @fopen($file, 'ab')) === FALSE)

			{

				return FALSE;

			}

			fclose($fp);

			@chmod($file, 0777);

			@unlink($file);

			return TRUE;

		}

		elseif ( ! is_file($file) OR ($fp = @fopen($file, 'ab')) === FALSE)

		{

			return FALSE;

		}

		fclose($fp);

		return TRUE;

	}

}

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

if ( ! function_exists('load_class'))

{

	/**

	 * Class registry

	 *

	 * This function acts as a singleton. If the requested class does not

	 * exist it is instantiated and set to a static variable. If it has

	 * previously been instantiated the variable is returned.

	 *

	 * @param	string	the class name being requested

	 * @param	string	the directory where the class should be found

	 * @param	string	an optional argument to pass to the class constructor

	 * @return	object

	 */

	function &load_class($class, $directory = 'libraries', $param = NULL)

	{

		static $_classes = array();

		// Does the class exist? If so, we're done...

		if (isset($_classes[$class]))

		{

			return $_classes[$class];

		}

		$name = FALSE;

		// Look for the class first in the local application/libraries folder

		// then in the native system/libraries folder

		foreach (array(APPPATH, BASEPATH) as $path)

		{

			if (file_exists($path.$directory.'/'.$class.'.php'))

			{

				$name = 'CI_'.$class;

				if (class_exists($name, FALSE) === FALSE)

				{

					require_once($path.$directory.'/'.$class.'.php');

				}

				break;

			}

		}

		// Is the request a class extension? If so we load it too

		if (file_exists(APPPATH.$directory.'/'.config_item('subclass_prefix').$class.'.php'))

		{

			$name = config_item('subclass_prefix').$class;

			if (class_exists($name, FALSE) === FALSE)

			{

				require_once(APPPATH.$directory.'/'.$name.'.php');

			}

		}

		// Did we find the class?

		if ($name === FALSE)

		{

			// Note: We use exit() rather than show_error() in order to avoid a

			// self-referencing loop with the Exceptions class

			set_status_header(503);

			echo 'Unable to locate the specified class: '.$class.'.php';

			exit(5); // EXIT_UNK_CLASS

		}

		// Keep track of what we just loaded

		is_loaded($class);

		$_classes[$class] = isset($param)

			? new $name($param)

			: new $name();

		return $_classes[$class];

	}

}

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

if ( ! function_exists('is_loaded'))

{

	/**

	 * Keeps track of which libraries have been loaded. This function is

	 * called by the load_class() function above

	 *

	 * @param	string

	 * @return	array

	 */

	function &is_loaded($class = '')

	{

		static $_is_loaded = array();

		if ($class !== '')

		{

			$_is_loaded[strtolower($class)] = $class;

		}

		return $_is_loaded;

	}

}

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

if ( ! function_exists('get_config'))

{

	/**

	 * Loads the main config.php file

	 *

	 * This function lets us grab the config file even if the Config class

	 * hasn't been instantiated yet

	 *

	 * @param	array

	 * @return	array

	 */

	function &get_config(Array $replace = array())

	{

		static $config;

		if (empty($config))

		{

			$file_path = APPPATH.'config/config.php';

			$found = FALSE;

			if (file_exists($file_path))

			{

				$found = TRUE;

				require($file_path);

			}

			// Is the config file in the environment folder?

			if (file_exists($file_path = APPPATH.'config/'.ENVIRONMENT.'/config.php'))

			{

				require($file_path);

			}

			elseif ( ! $found)

			{

				set_status_header(503);

				echo 'The configuration file does not exist.';

				exit(3); // EXIT_CONFIG

			}

			// Does the $config array exist in the file?

			if ( ! isset($config) OR ! is_array($config))

			{

				set_status_header(503);

				echo 'Your config file does not appear to be formatted correctly.';

				exit(3); // EXIT_CONFIG

			}

		}

		// Are any values being dynamically added or replaced?

		foreach ($replace as $key => $val)

		{

			$config[$key] = $val;

		}

		return $config;

	}

}

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

if ( ! function_exists('config_item'))

{

	/**

	 * Returns the specified config item

	 *

	 * @param	string

	 * @return	mixed

	 */

	function config_item($item)

	{

		static $_config;

		if (empty($_config))

		{

			// references cannot be directly assigned to static variables, so we use an array

			$_config[0] =& get_config();

		}

		return isset($_config[0][$item]) ? $_config[0][$item] : NULL;

	}

}

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

if ( ! function_exists('get_mimes'))

{

	/**

	 * Returns the MIME types array from config/mimes.php

	 *

	 * @return	array

	 */

	function &get_mimes()

	{

		static $_mimes;

		if (empty($_mimes))

		{

			if (file_exists(APPPATH.'config/'.ENVIRONMENT.'/mimes.php'))

			{

				$_mimes = include(APPPATH.'config/'.ENVIRONMENT.'/mimes.php');

			}

			elseif (file_exists(APPPATH.'config/mimes.php'))

			{

				$_mimes = include(APPPATH.'config/mimes.php');

			}

			else

			{

				$_mimes = array();

			}

		}

		return $_mimes;

	}

}

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

if ( ! function_exists('is_https'))

{

	/**

	 * Is HTTPS?

	 *

	 * Determines if the application is accessed via an encrypted

	 * (HTTPS) connection.

	 *

	 * @return	bool

	 */

	function is_https()

	{

		if ( ! empty($_SERVER['HTTPS']) && strtolower($_SERVER['HTTPS']) !== 'off')

		{

			return TRUE;

		}

		elseif (isset($_SERVER['HTTP_X_FORWARDED_PROTO']) && strtolower($_SERVER['HTTP_X_FORWARDED_PROTO']) === 'https')

		{

			return TRUE;

		}

		elseif ( ! empty($_SERVER['HTTP_FRONT_END_HTTPS']) && strtolower($_SERVER['HTTP_FRONT_END_HTTPS']) !== 'off')

		{

			return TRUE;

		}

		return FALSE;

	}

}

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

if ( ! function_exists('is_cli'))

{

	/**

	 * Is CLI?

	 *

	 * Test to see if a request was made from the command line.

	 *

	 * @return 	bool

	 */

	function is_cli()

	{

		return (PHP_SAPI === 'cli' OR defined('STDIN'));

	}

}

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

if ( ! function_exists('show_error'))

{

	/**

	 * Error Handler

	 *

	 * This function lets us invoke the exception class and

	 * display errors using the standard error template located

	 * in application/views/errors/error_general.php

	 * This function will send the error page directly to the

	 * browser and exit.

	 *

	 * @param	string

	 * @param	int

	 * @param	string

	 * @return	void

	 */

	function show_error($message, $status_code = 500, $heading = 'An Error Was Encountered')

	{

		$status_code = abs($status_code);

		if ($status_code < 100)

		{

			$exit_status = $status_code + 9; // 9 is EXIT__AUTO_MIN

			if ($exit_status > 125) // 125 is EXIT__AUTO_MAX

			{

				$exit_status = 1; // EXIT_ERROR

			}

			$status_code = 500;

		}

		else

		{

			$exit_status = 1; // EXIT_ERROR

		}

		$_error =& load_class('Exceptions', 'core');

		echo $_error->show_error($heading, $message, 'error_general', $status_code);

		exit($exit_status);

	}

}

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

if ( ! function_exists('show_404'))

{

	/**

	 * 404 Page Handler

	 *

	 * This function is similar to the show_error() function above

	 * However, instead of the standard error template it displays

	 * 404 errors.

	 *

	 * @param	string

	 * @param	bool

	 * @return	void

	 */

	function show_404($page = '', $log_error = TRUE)

	{

		$_error =& load_class('Exceptions', 'core');

		$_error->show_404($page, $log_error);

		exit(4); // EXIT_UNKNOWN_FILE

	}

}

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

if ( ! function_exists('log_message'))

{

	/**

	 * Error Logging Interface

	 *

	 * We use this as a simple mechanism to access the logging

	 * class and send messages to be logged.

	 *

	 * @param	string	the error level: 'error', 'debug' or 'info'

	 * @param	string	the error message

	 * @return	void

	 */

	function log_message($level, $message)

	{

		static $_log;

		if ($_log === NULL)

		{

			// references cannot be directly assigned to static variables, so we use an array

			$_log[0] =& load_class('Log', 'core');

		}

		$_log[0]->write_log($level, $message);

	}

}

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

if ( ! function_exists('set_status_header'))

{

	/**

	 * Set HTTP Status Header

	 *

	 * @param	int	the status code

	 * @param	string

	 * @return	void

	 */

	function set_status_header($code = 200, $text = '')

	{

		if (is_cli())

		{

			return;

		}

		if (empty($code) OR ! is_numeric($code))

		{

			show_error('Status codes must be numeric', 500);

		}

		if (empty($text))

		{

			is_int($code) OR $code = (int) $code;

			$stati = array(

				100	=> 'Continue',

				101	=> 'Switching Protocols',

				200	=> 'OK',

				201	=> 'Created',

				202	=> 'Accepted',

				203	=> 'Non-Authoritative Information',

				204	=> 'No Content',

				205	=> 'Reset Content',

				206	=> 'Partial Content',

				300	=> 'Multiple Choices',

				301	=> 'Moved Permanently',

				302	=> 'Found',

				303	=> 'See Other',

				304	=> 'Not Modified',

				305	=> 'Use Proxy',

				307	=> 'Temporary Redirect',

				400	=> 'Bad Request',

				401	=> 'Unauthorized',

				402	=> 'Payment Required',

				403	=> 'Forbidden',

				404	=> 'Not Found',

				405	=> 'Method Not Allowed',

				406	=> 'Not Acceptable',

				407	=> 'Proxy Authentication Required',

				408	=> 'Request Timeout',

				409	=> 'Conflict',

				410	=> 'Gone',

				411	=> 'Length Required',

				412	=> 'Precondition Failed',

				413	=> 'Request Entity Too Large',

				414	=> 'Request-URI Too Long',

				415	=> 'Unsupported Media Type',

				416	=> 'Requested Range Not Satisfiable',

				417	=> 'Expectation Failed',

				422	=> 'Unprocessable Entity',

				500	=> 'Internal Server Error',

				501	=> 'Not Implemented',

				502	=> 'Bad Gateway',

				503	=> 'Service Unavailable',

				504	=> 'Gateway Timeout',

				505	=> 'HTTP Version Not Supported'

			);

			if (isset($stati[$code]))

			{

				$text = $stati[$code];

			}

			else

			{

				show_error('No status text available. Please check your status code number or supply your own message text.', 500);

			}

		}

		if (strpos(PHP_SAPI, 'cgi') === 0)

		{

			header('Status: '.$code.' '.$text, TRUE);

		}

		else

		{

			$server_protocol = isset($_SERVER['SERVER_PROTOCOL']) ? $_SERVER['SERVER_PROTOCOL'] : 'HTTP/1.1';

			header($server_protocol.' '.$code.' '.$text, TRUE, $code);

		}

	}

}

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

if ( ! function_exists('_error_handler'))

{

	/**

	 * Error Handler

	 *

	 * This is the custom error handler that is declared at the (relative)

	 * top of CodeIgniter.php. The main reason we use this is to permit

	 * PHP errors to be logged in our own log files since the user may

	 * not have access to server logs. Since this function effectively

	 * intercepts PHP errors, however, we also need to display errors

	 * based on the current error_reporting level.

	 * We do that with the use of a PHP error template.

	 *

	 * @param	int	$severity

	 * @param	string	$message

	 * @param	string	$filepath

	 * @param	int	$line

	 * @return	void

	 */

	function _error_handler($severity, $message, $filepath, $line)

	{

		$is_error = (((E_ERROR | E_COMPILE_ERROR | E_CORE_ERROR | E_USER_ERROR) & $severity) === $severity);

		// When an error occurred, set the status header to '500 Internal Server Error'

		// to indicate to the client something went wrong.

		// This can't be done within the $_error->show_php_error method because

		// it is only called when the display_errors flag is set (which isn't usually

		// the case in a production environment) or when errors are ignored because

		// they are above the error_reporting threshold.

		if ($is_error)

		{

			set_status_header(500);

		}

		// Should we ignore the error? We'll get the current error_reporting

		// level and add its bits with the severity bits to find out.

		if (($severity & error_reporting()) !== $severity)

		{

			return;

		}

		$_error =& load_class('Exceptions', 'core');

		$_error->log_exception($severity, $message, $filepath, $line);

		// Should we display the error?

		if (str_ireplace(array('off', 'none', 'no', 'false', 'null'), '', ini_get('display_errors')))

		{

			$_error->show_php_error($severity, $message, $filepath, $line);

		}

		// If the error is fatal, the execution of the script should be stopped because

		// errors can't be recovered from. Halting the script conforms with PHP's

		// default error handling. See http://www.php.net/manual/en/errorfunc.constants.php

		if ($is_error)

		{

			exit(1); // EXIT_ERROR

		}

	}

}

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

if ( ! function_exists('_exception_handler'))

{

	/**

	 * Exception Handler

	 *

	 * Sends uncaught exceptions to the logger and displays them

	 * only if display_errors is On so that they don't show up in

	 * production environments.

	 *

	 * @param	Exception	$exception

	 * @return	void

	 */

	function _exception_handler($exception)

	{

		$_error =& load_class('Exceptions', 'core');

		$_error->log_exception('error', 'Exception: '.$exception->getMessage(), $exception->getFile(), $exception->getLine());

		// Should we display the error?

		if (str_ireplace(array('off', 'none', 'no', 'false', 'null'), '', ini_get('display_errors')))

		{

			$_error->show_exception($exception);

		}

		exit(1); // EXIT_ERROR

	}

}

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

if ( ! function_exists('_shutdown_handler'))

{

	/**

	 * Shutdown Handler

	 *

	 * This is the shutdown handler that is declared at the top

	 * of CodeIgniter.php. The main reason we use this is to simulate

	 * a complete custom exception handler.

	 *

	 * E_STRICT is purposively neglected because such events may have

	 * been caught. Duplication or none? None is preferred for now.

	 *

	 * @link	http://insomanic.me.uk/post/229851073/php-trick-catching-fatal-errors-e-error-with-a

	 * @return	void

	 */

	function _shutdown_handler()

	{

		$last_error = error_get_last();

		if (isset($last_error) &&

			($last_error['type'] & (E_ERROR | E_PARSE | E_CORE_ERROR | E_CORE_WARNING | E_COMPILE_ERROR | E_COMPILE_WARNING)))

		{

			_error_handler($last_error['type'], $last_error['message'], $last_error['file'], $last_error['line']);

		}

	}

}

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

if ( ! function_exists('remove_invisible_characters'))

{

	/**

	 * Remove Invisible Characters

	 *

	 * This prevents sandwiching null characters

	 * between ascii characters, like Java\0script.

	 *

	 * @param	string

	 * @param	bool

	 * @return	string

	 */

	function remove_invisible_characters($str, $url_encoded = TRUE)

	{

		$non_displayables = array();

		// every control character except newline (dec 10),

		// carriage return (dec 13) and horizontal tab (dec 09)

		if ($url_encoded)

		{

			$non_displayables[] = '/%0[0-8bcef]/i';	// url encoded 00-08, 11, 12, 14, 15

			$non_displayables[] = '/%1[0-9a-f]/i';	// url encoded 16-31

		}

		$non_displayables[] = '/[\x00-\x08\x0B\x0C\x0E-\x1F\x7F]+/S';	// 00-08, 11, 12, 14-31, 127

		do

		{

			$str = preg_replace($non_displayables, '', $str, -1, $count);

		}

		while ($count);

		return $str;

	}

}

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

if ( ! function_exists('html_escape'))

{

	/**

	 * Returns HTML escaped variable.

	 *

	 * @param	mixed	$var		The input string or array of strings to be escaped.

	 * @param	bool	$double_encode	$double_encode set to FALSE prevents escaping twice.

	 * @return	mixed			The escaped string or array of strings as a result.

	 */

	function html_escape($var, $double_encode = TRUE)

	{

		if (empty($var))

		{

			return $var;

		}

		if (is_array($var))

		{

			foreach (array_keys($var) as $key)

			{

				$var[$key] = html_escape($var[$key], $double_encode);

			}

			return $var;

		}

		return htmlspecialchars($var, ENT_QUOTES, config_item('charset'), $double_encode);

	}

}

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

if ( ! function_exists('_stringify_attributes'))

{

	/**

	 * Stringify attributes for use in HTML tags.

	 *

	 * Helper function used to convert a string, array, or object

	 * of attributes to a string.

	 *

	 * @param	mixed	string, array, object

	 * @param	bool

	 * @return	string

	 */

	function _stringify_attributes($attributes, $js = FALSE)

	{

		$atts = NULL;

		if (empty($attributes))

		{

			return $atts;

		}

		if (is_string($attributes))

		{

			return ' '.$attributes;

		}

		$attributes = (array) $attributes;

		foreach ($attributes as $key => $val)

		{

			$atts .= ($js) ? $key.'='.$val.',' : ' '.$key.'="'.$val.'"';

		}

		return rtrim($atts, ',');

	}

}

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

if ( ! function_exists('function_usable'))

{

	/**

	 * Function usable

	 *

	 * Executes a function_exists() check, and if the Suhosin PHP

	 * extension is loaded - checks whether the function that is

	 * checked might be disabled in there as well.

	 *

	 * This is useful as function_exists() will return FALSE for

	 * functions disabled via the *disable_functions* php.ini

	 * setting, but not for *suhosin.executor.func.blacklist* and

	 * *suhosin.executor.disable_eval*. These settings will just

	 * terminate script execution if a disabled function is executed.

	 *

	 * The above described behavior turned out to be a bug in Suhosin,

	 * but even though a fix was commited for 0.9.34 on 2012-02-12,

	 * that version is yet to be released. This function will therefore

	 * be just temporary, but would probably be kept for a few years.

	 *

	 * @link	http://www.hardened-php.net/suhosin/

	 * @param	string	$function_name	Function to check for

	 * @return	bool	TRUE if the function exists and is safe to call,

	 *			FALSE otherwise.

	 */

	function function_usable($function_name)

	{

		static $_suhosin_func_blacklist;

		if (function_exists($function_name))

		{

			if ( ! isset($_suhosin_func_blacklist))

			{

				$_suhosin_func_blacklist = extension_loaded('suhosin')

					? explode(',', trim(ini_get('suhosin.executor.func.blacklist')))

					: array();

			}

			return ! in_array($function_name, $_suhosin_func_blacklist, TRUE);

		}

		return FALSE;

	}

}