system/core/URI.php - code-igniter-v3-giggi - Gitiles

 <?php
 /**
  * CodeIgniter
  *
  * An open source application development framework for PHP
  *
  * This content is released under the MIT License (MIT)
  *
  * Copyright (c) 2014 - 2018, 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 - 2018, 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');

 /**
  * URI Class
  *
  * Parses URIs and determines routing
  *
  * @package		CodeIgniter
  * @subpackage	Libraries
  * @category	URI
  * @author		EllisLab Dev Team
  * @link		https://codeigniter.com/user_guide/libraries/uri.html
  */
 class CI_URI {

 	/**
 	 * List of cached URI segments
 	 *
 	 * @var	array
 	 */
 	public $keyval = array();

 	/**
 	 * Current URI string
 	 *
 	 * @var	string
 	 */
 	public $uri_string = '';

 	/**
 	 * List of URI segments
 	 *
 	 * Starts at 1 instead of 0.
 	 *
 	 * @var	array
 	 */
 	public $segments = array();

 	/**
 	 * List of routed URI segments
 	 *
 	 * Starts at 1 instead of 0.
 	 *
 	 * @var	array
 	 */
 	public $rsegments = array();

 	/**
 	 * Permitted URI chars
 	 *
 	 * PCRE character group allowed in URI segments
 	 *
 	 * @var	string
 	 */
 	protected $_permitted_uri_chars;

 	/**
 	 * Class constructor
 	 *
 	 * @return	void
 	 */
 	public function __construct()
 	{
 		$this->config =& load_class('Config', 'core');

 		// If query strings are enabled, we don't need to parse any segments.
 		// However, they don't make sense under CLI.
 		if (is_cli() OR $this->config->item('enable_query_strings') !== TRUE)
 		{
 			$this->_permitted_uri_chars = $this->config->item('permitted_uri_chars');

 			// If it's a CLI request, ignore the configuration
 			if (is_cli())
 			{
 				$uri = $this->_parse_argv();
 			}
 			else
 			{
 				$protocol = $this->config->item('uri_protocol');
 				empty($protocol) && $protocol = 'REQUEST_URI';

 				switch ($protocol)
 				{
 					case 'AUTO': // For BC purposes only
 					case 'REQUEST_URI':
 						$uri = $this->_parse_request_uri();
 						break;
 					case 'QUERY_STRING':
 						$uri = $this->_parse_query_string();
 						break;
 					case 'PATH_INFO':
 					default:
 						$uri = isset($_SERVER[$protocol])
 							? $_SERVER[$protocol]
 							: $this->_parse_request_uri();
 						break;
 				}
 			}

 			$this->_set_uri_string($uri);
 		}

 		log_message('info', 'URI Class Initialized');
 	}

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

 	/**
 	 * Set URI String
 	 *
 	 * @param 	string	$str
 	 * @return	void
 	 */
 	protected function _set_uri_string($str)
 	{
 		// Filter out control characters and trim slashes
 		$this->uri_string = trim(remove_invisible_characters($str, FALSE), '/');

 		if ($this->uri_string !== '')
 		{
 			// Remove the URL suffix, if present
 			if (($suffix = (string) $this->config->item('url_suffix')) !== '')
 			{
 				$slen = strlen($suffix);

 				if (substr($this->uri_string, -$slen) === $suffix)
 				{
 					$this->uri_string = substr($this->uri_string, 0, -$slen);
 				}
 			}

 			$this->segments[0] = NULL;
 			// Populate the segments array
 			foreach (explode('/', trim($this->uri_string, '/')) as $val)
 			{
 				$val = trim($val);
 				// Filter segments for security
 				$this->filter_uri($val);

 				if ($val !== '')
 				{
 					$this->segments[] = $val;
 				}
 			}

 			unset($this->segments[0]);
 		}
 	}

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

 	/**
 	 * Parse REQUEST_URI
 	 *
 	 * Will parse REQUEST_URI and automatically detect the URI from it,
 	 * while fixing the query string if necessary.
 	 *
 	 * @return	string
 	 */
 	protected function _parse_request_uri()
 	{
 		if ( ! isset($_SERVER['REQUEST_URI'], $_SERVER['SCRIPT_NAME']))
 		{
 			return '';
 		}

 		// parse_url() returns false if no host is present, but the path or query string
 		// contains a colon followed by a number
 		$uri = parse_url('http://dummy'.$_SERVER['REQUEST_URI']);
 		$query = isset($uri['query']) ? $uri['query'] : '';
 		$uri = isset($uri['path']) ? $uri['path'] : '';

 		if (isset($_SERVER['SCRIPT_NAME'][0]))
 		{
 			if (strpos($uri, $_SERVER['SCRIPT_NAME']) === 0)
 			{
 				$uri = (string) substr($uri, strlen($_SERVER['SCRIPT_NAME']));
 			}
 			elseif (strpos($uri, dirname($_SERVER['SCRIPT_NAME'])) === 0)
 			{
 				$uri = (string) substr($uri, strlen(dirname($_SERVER['SCRIPT_NAME'])));
 			}
 		}

 		// This section ensures that even on servers that require the URI to be in the query string (Nginx) a correct
 		// URI is found, and also fixes the QUERY_STRING server var and $_GET array.
 		if (trim($uri, '/') === '' && strncmp($query, '/', 1) === 0)
 		{
 			$query = explode('?', $query, 2);
 			$uri = $query[0];
 			$_SERVER['QUERY_STRING'] = isset($query[1]) ? $query[1] : '';
 		}
 		else
 		{
 			$_SERVER['QUERY_STRING'] = $query;
 		}

 		parse_str($_SERVER['QUERY_STRING'], $_GET);

 		if ($uri === '/' OR $uri === '')
 		{
 			return '/';
 		}

 		// Do some final cleaning of the URI and return it
 		return $this->_remove_relative_directory($uri);
 	}

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

 	/**
 	 * Parse QUERY_STRING
 	 *
 	 * Will parse QUERY_STRING and automatically detect the URI from it.
 	 *
 	 * @return	string
 	 */
 	protected function _parse_query_string()
 	{
 		$uri = isset($_SERVER['QUERY_STRING']) ? $_SERVER['QUERY_STRING'] : @getenv('QUERY_STRING');

 		if (trim($uri, '/') === '')
 		{
 			return '';
 		}
 		elseif (strncmp($uri, '/', 1) === 0)
 		{
 			$uri = explode('?', $uri, 2);
 			$_SERVER['QUERY_STRING'] = isset($uri[1]) ? $uri[1] : '';
 			$uri = $uri[0];
 		}

 		parse_str($_SERVER['QUERY_STRING'], $_GET);

 		return $this->_remove_relative_directory($uri);
 	}

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

 	/**
 	 * Parse CLI arguments
 	 *
 	 * Take each command line argument and assume it is a URI segment.
 	 *
 	 * @return	string
 	 */
 	protected function _parse_argv()
 	{
 		$args = array_slice($_SERVER['argv'], 1);
 		return $args ? implode('/', $args) : '';
 	}

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

 	/**
 	 * Remove relative directory (../) and multi slashes (///)
 	 *
 	 * Do some final cleaning of the URI and return it, currently only used in self::_parse_request_uri()
 	 *
 	 * @param	string	$uri
 	 * @return	string
 	 */
 	protected function _remove_relative_directory($uri)
 	{
 		$uris = array();
 		$tok = strtok($uri, '/');
 		while ($tok !== FALSE)
 		{
 			if (( ! empty($tok) OR $tok === '0') && $tok !== '..')
 			{
 				$uris[] = $tok;
 			}
 			$tok = strtok('/');
 		}

 		return implode('/', $uris);
 	}

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

 	/**
 	 * Filter URI
 	 *
 	 * Filters segments for malicious characters.
 	 *
 	 * @param	string	$str
 	 * @return	void
 	 */
 	public function filter_uri(&$str)
 	{
 		if ( ! empty($str) && ! empty($this->_permitted_uri_chars) && ! preg_match('/^['.$this->_permitted_uri_chars.']+$/i'.(UTF8_ENABLED ? 'u' : ''), $str))
 		{
 			show_error('The URI you submitted has disallowed characters.', 400);
 		}
 	}

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

 	/**
 	 * Fetch URI Segment
 	 *
 	 * @see		CI_URI::$segments
 	 * @param	int		$n		Index
 	 * @param	mixed		$no_result	What to return if the segment index is not found
 	 * @return	mixed
 	 */
 	public function segment($n, $no_result = NULL)
 	{
 		return isset($this->segments[$n]) ? $this->segments[$n] : $no_result;
 	}

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

 	/**
 	 * Fetch URI "routed" Segment
 	 *
 	 * Returns the re-routed URI segment (assuming routing rules are used)
 	 * based on the index provided. If there is no routing, will return
 	 * the same result as CI_URI::segment().
 	 *
 	 * @see		CI_URI::$rsegments
 	 * @see		CI_URI::segment()
 	 * @param	int		$n		Index
 	 * @param	mixed		$no_result	What to return if the segment index is not found
 	 * @return	mixed
 	 */
 	public function rsegment($n, $no_result = NULL)
 	{
 		return isset($this->rsegments[$n]) ? $this->rsegments[$n] : $no_result;
 	}

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

 	/**
 	 * URI to assoc
 	 *
 	 * Generates an associative array of URI data starting at the supplied
 	 * segment index. For example, if this is your URI:
 	 *
 	 *	example.com/user/search/name/joe/location/UK/gender/male
 	 *
 	 * You can use this method to generate an array with this prototype:
 	 *
 	 *	array (
 	 *		name => joe
 	 *		location => UK
 	 *		gender => male
 	 *	 )
 	 *
 	 * @param	int	$n		Index (default: 3)
 	 * @param	array	$default	Default values
 	 * @return	array
 	 */
 	public function uri_to_assoc($n = 3, $default = array())
 	{
 		return $this->_uri_to_assoc($n, $default, 'segment');
 	}

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

 	/**
 	 * Routed URI to assoc
 	 *
 	 * Identical to CI_URI::uri_to_assoc(), only it uses the re-routed
 	 * segment array.
 	 *
 	 * @see		CI_URI::uri_to_assoc()
 	 * @param 	int	$n		Index (default: 3)
 	 * @param 	array	$default	Default values
 	 * @return 	array
 	 */
 	public function ruri_to_assoc($n = 3, $default = array())
 	{
 		return $this->_uri_to_assoc($n, $default, 'rsegment');
 	}

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

 	/**
 	 * Internal URI-to-assoc
 	 *
 	 * Generates a key/value pair from the URI string or re-routed URI string.
 	 *
 	 * @used-by	CI_URI::uri_to_assoc()
 	 * @used-by	CI_URI::ruri_to_assoc()
 	 * @param	int	$n		Index (default: 3)
 	 * @param	array	$default	Default values
 	 * @param	string	$which		Array name ('segment' or 'rsegment')
 	 * @return	array
 	 */
 	protected function _uri_to_assoc($n = 3, $default = array(), $which = 'segment')
 	{
 		if ( ! is_numeric($n))
 		{
 			return $default;
 		}

 		if (isset($this->keyval[$which], $this->keyval[$which][$n]))
 		{
 			return $this->keyval[$which][$n];
 		}

 		$total_segments = "total_{$which}s";
 		$segment_array = "{$which}_array";

 		if ($this->$total_segments() < $n)
 		{
 			return (count($default) === 0)
 				? array()
 				: array_fill_keys($default, NULL);
 		}

 		$segments = array_slice($this->$segment_array(), ($n - 1));
 		$i = 0;
 		$lastval = '';
 		$retval = array();
 		foreach ($segments as $seg)
 		{
 			if ($i % 2)
 			{
 				$retval[$lastval] = $seg;
 			}
 			else
 			{
 				$retval[$seg] = NULL;
 				$lastval = $seg;
 			}

 			$i++;
 		}

 		if (count($default) > 0)
 		{
 			foreach ($default as $val)
 			{
 				if ( ! array_key_exists($val, $retval))
 				{
 					$retval[$val] = NULL;
 				}
 			}
 		}

 		// Cache the array for reuse
 		isset($this->keyval[$which]) OR $this->keyval[$which] = array();
 		$this->keyval[$which][$n] = $retval;
 		return $retval;
 	}

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

 	/**
 	 * Assoc to URI
 	 *
 	 * Generates a URI string from an associative array.
 	 *
 	 * @param	array	$array	Input array of key/value pairs
 	 * @return	string	URI string
 	 */
 	public function assoc_to_uri($array)
 	{
 		$temp = array();
 		foreach ((array) $array as $key => $val)
 		{
 			$temp[] = $key;
 			$temp[] = $val;
 		}

 		return implode('/', $temp);
 	}

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

 	/**
 	 * Slash segment
 	 *
 	 * Fetches an URI segment with a slash.
 	 *
 	 * @param	int	$n	Index
 	 * @param	string	$where	Where to add the slash ('trailing' or 'leading')
 	 * @return	string
 	 */
 	public function slash_segment($n, $where = 'trailing')
 	{
 		return $this->_slash_segment($n, $where, 'segment');
 	}

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

 	/**
 	 * Slash routed segment
 	 *
 	 * Fetches an URI routed segment with a slash.
 	 *
 	 * @param	int	$n	Index
 	 * @param	string	$where	Where to add the slash ('trailing' or 'leading')
 	 * @return	string
 	 */
 	public function slash_rsegment($n, $where = 'trailing')
 	{
 		return $this->_slash_segment($n, $where, 'rsegment');
 	}

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

 	/**
 	 * Internal Slash segment
 	 *
 	 * Fetches an URI Segment and adds a slash to it.
 	 *
 	 * @used-by	CI_URI::slash_segment()
 	 * @used-by	CI_URI::slash_rsegment()
 	 *
 	 * @param	int	$n	Index
 	 * @param	string	$where	Where to add the slash ('trailing' or 'leading')
 	 * @param	string	$which	Array name ('segment' or 'rsegment')
 	 * @return	string
 	 */
 	protected function _slash_segment($n, $where = 'trailing', $which = 'segment')
 	{
 		$leading = $trailing = '/';

 		if ($where === 'trailing')
 		{
 			$leading	= '';
 		}
 		elseif ($where === 'leading')
 		{
 			$trailing	= '';
 		}

 		return $leading.$this->$which($n).$trailing;
 	}

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

 	/**
 	 * Segment Array
 	 *
 	 * @return	array	CI_URI::$segments
 	 */
 	public function segment_array()
 	{
 		return $this->segments;
 	}

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

 	/**
 	 * Routed Segment Array
 	 *
 	 * @return	array	CI_URI::$rsegments
 	 */
 	public function rsegment_array()
 	{
 		return $this->rsegments;
 	}

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

 	/**
 	 * Total number of segments
 	 *
 	 * @return	int
 	 */
 	public function total_segments()
 	{
 		return count($this->segments);
 	}

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

 	/**
 	 * Total number of routed segments
 	 *
 	 * @return	int
 	 */
 	public function total_rsegments()
 	{
 		return count($this->rsegments);
 	}

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

 	/**
 	 * Fetch URI string
 	 *
 	 * @return	string	CI_URI::$uri_string
 	 */
 	public function uri_string()
 	{
 		return $this->uri_string;
 	}

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

 	/**
 	 * Fetch Re-routed URI string
 	 *
 	 * @return	string
 	 */
 	public function ruri_string()
 	{
 		return ltrim(load_class('Router', 'core')->directory, '/').implode('/', $this->rsegments);
 	}

 }
	<?php
	/**
	* CodeIgniter
	*
	* An open source application development framework for PHP
	*
	* This content is released under the MIT License (MIT)
	*
	* Copyright (c) 2014 - 2018, 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 - 2018, 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');

	/**
	* URI Class
	*
	* Parses URIs and determines routing
	*
	* @package CodeIgniter
	* @subpackage Libraries
	* @category URI
	* @author EllisLab Dev Team
	* @link https://codeigniter.com/user_guide/libraries/uri.html
	*/
	class CI_URI {

	/**
	* List of cached URI segments
	*
	* @var array
	*/
	public $keyval = array();

	/**
	* Current URI string
	*
	* @var string
	*/
	public $uri_string = '';

	/**
	* List of URI segments
	*
	* Starts at 1 instead of 0.
	*
	* @var array
	*/
	public $segments = array();

	/**
	* List of routed URI segments
	*
	* Starts at 1 instead of 0.
	*
	* @var array
	*/
	public $rsegments = array();

	/**
	* Permitted URI chars
	*
	* PCRE character group allowed in URI segments
	*
	* @var string
	*/
	protected $_permitted_uri_chars;

	/**
	* Class constructor
	*
	* @return void
	*/
	public function __construct()
	{
	$this->config =& load_class('Config', 'core');

	// If query strings are enabled, we don't need to parse any segments.
	// However, they don't make sense under CLI.
	if (is_cli() OR $this->config->item('enable_query_strings') !== TRUE)
	{
	$this->_permitted_uri_chars = $this->config->item('permitted_uri_chars');

	// If it's a CLI request, ignore the configuration
	if (is_cli())
	{
	$uri = $this->_parse_argv();
	}
	else
	{
	$protocol = $this->config->item('uri_protocol');
	empty($protocol) && $protocol = 'REQUEST_URI';

	switch ($protocol)
	{
	case 'AUTO': // For BC purposes only
	case 'REQUEST_URI':
	$uri = $this->_parse_request_uri();
	break;
	case 'QUERY_STRING':
	$uri = $this->_parse_query_string();
	break;
	case 'PATH_INFO':
	default:
	$uri = isset($_SERVER[$protocol])
	? $_SERVER[$protocol]
	: $this->_parse_request_uri();
	break;
	}
	}

	$this->_set_uri_string($uri);
	}

	log_message('info', 'URI Class Initialized');
	}

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

	/**
	* Set URI String
	*
	* @param string $str
	* @return void
	*/
	protected function _set_uri_string($str)
	{
	// Filter out control characters and trim slashes
	$this->uri_string = trim(remove_invisible_characters($str, FALSE), '/');

	if ($this->uri_string !== '')
	{
	// Remove the URL suffix, if present
	if (($suffix = (string) $this->config->item('url_suffix')) !== '')
	{
	$slen = strlen($suffix);

	if (substr($this->uri_string, -$slen) === $suffix)
	{
	$this->uri_string = substr($this->uri_string, 0, -$slen);
	}
	}

	$this->segments[0] = NULL;
	// Populate the segments array
	foreach (explode('/', trim($this->uri_string, '/')) as $val)
	{
	$val = trim($val);
	// Filter segments for security
	$this->filter_uri($val);

	if ($val !== '')
	{
	$this->segments[] = $val;
	}
	}

	unset($this->segments[0]);
	}
	}

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

	/**
	* Parse REQUEST_URI
	*
	* Will parse REQUEST_URI and automatically detect the URI from it,
	* while fixing the query string if necessary.
	*
	* @return string
	*/
	protected function _parse_request_uri()
	{
	if ( ! isset($_SERVER['REQUEST_URI'], $_SERVER['SCRIPT_NAME']))
	{
	return '';
	}

	// parse_url() returns false if no host is present, but the path or query string
	// contains a colon followed by a number
	$uri = parse_url('http://dummy'.$_SERVER['REQUEST_URI']);
	$query = isset($uri['query']) ? $uri['query'] : '';
	$uri = isset($uri['path']) ? $uri['path'] : '';

	if (isset($_SERVER['SCRIPT_NAME'][0]))
	{
	if (strpos($uri, $_SERVER['SCRIPT_NAME']) === 0)
	{
	$uri = (string) substr($uri, strlen($_SERVER['SCRIPT_NAME']));
	}
	elseif (strpos($uri, dirname($_SERVER['SCRIPT_NAME'])) === 0)
	{
	$uri = (string) substr($uri, strlen(dirname($_SERVER['SCRIPT_NAME'])));
	}
	}

	// This section ensures that even on servers that require the URI to be in the query string (Nginx) a correct
	// URI is found, and also fixes the QUERY_STRING server var and $_GET array.
	if (trim($uri, '/') === '' && strncmp($query, '/', 1) === 0)
	{
	$query = explode('?', $query, 2);
	$uri = $query[0];
	$_SERVER['QUERY_STRING'] = isset($query[1]) ? $query[1] : '';
	}
	else
	{
	$_SERVER['QUERY_STRING'] = $query;
	}

	parse_str($_SERVER['QUERY_STRING'], $_GET);

	if ($uri === '/' OR $uri === '')
	{
	return '/';
	}

	// Do some final cleaning of the URI and return it
	return $this->_remove_relative_directory($uri);
	}

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

	/**
	* Parse QUERY_STRING
	*
	* Will parse QUERY_STRING and automatically detect the URI from it.
	*
	* @return string
	*/
	protected function _parse_query_string()
	{
	$uri = isset($_SERVER['QUERY_STRING']) ? $_SERVER['QUERY_STRING'] : @getenv('QUERY_STRING');

	if (trim($uri, '/') === '')
	{
	return '';
	}
	elseif (strncmp($uri, '/', 1) === 0)
	{
	$uri = explode('?', $uri, 2);
	$_SERVER['QUERY_STRING'] = isset($uri[1]) ? $uri[1] : '';
	$uri = $uri[0];
	}

	parse_str($_SERVER['QUERY_STRING'], $_GET);

	return $this->_remove_relative_directory($uri);
	}

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

	/**
	* Parse CLI arguments
	*
	* Take each command line argument and assume it is a URI segment.
	*
	* @return string
	*/
	protected function _parse_argv()
	{
	$args = array_slice($_SERVER['argv'], 1);
	return $args ? implode('/', $args) : '';
	}

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

	/**
	* Remove relative directory (../) and multi slashes (///)
	*
	* Do some final cleaning of the URI and return it, currently only used in self::_parse_request_uri()
	*
	* @param string $uri
	* @return string
	*/
	protected function _remove_relative_directory($uri)
	{
	$uris = array();
	$tok = strtok($uri, '/');
	while ($tok !== FALSE)
	{
	if (( ! empty($tok) OR $tok === '0') && $tok !== '..')
	{
	$uris[] = $tok;
	}
	$tok = strtok('/');
	}

	return implode('/', $uris);
	}

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

	/**
	* Filter URI
	*
	* Filters segments for malicious characters.
	*
	* @param string $str
	* @return void
	*/
	public function filter_uri(&$str)
	{
	if ( ! empty($str) && ! empty($this->_permitted_uri_chars) && ! preg_match('/^['.$this->_permitted_uri_chars.']+$/i'.(UTF8_ENABLED ? 'u' : ''), $str))
	{
	show_error('The URI you submitted has disallowed characters.', 400);
	}
	}

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

	/**
	* Fetch URI Segment
	*
	* @see CI_URI::$segments
	* @param int $n Index
	* @param mixed $no_result What to return if the segment index is not found
	* @return mixed
	*/
	public function segment($n, $no_result = NULL)
	{
	return isset($this->segments[$n]) ? $this->segments[$n] : $no_result;
	}

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

	/**
	* Fetch URI "routed" Segment
	*
	* Returns the re-routed URI segment (assuming routing rules are used)
	* based on the index provided. If there is no routing, will return
	* the same result as CI_URI::segment().
	*
	* @see CI_URI::$rsegments
	* @see CI_URI::segment()
	* @param int $n Index
	* @param mixed $no_result What to return if the segment index is not found
	* @return mixed
	*/
	public function rsegment($n, $no_result = NULL)
	{
	return isset($this->rsegments[$n]) ? $this->rsegments[$n] : $no_result;
	}

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

	/**
	* URI to assoc
	*
	* Generates an associative array of URI data starting at the supplied
	* segment index. For example, if this is your URI:
	*
	* example.com/user/search/name/joe/location/UK/gender/male
	*
	* You can use this method to generate an array with this prototype:
	*
	* array (
	* name => joe
	* location => UK
	* gender => male
	* )
	*
	* @param int $n Index (default: 3)
	* @param array $default Default values
	* @return array
	*/
	public function uri_to_assoc($n = 3, $default = array())
	{
	return $this->_uri_to_assoc($n, $default, 'segment');
	}

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

	/**
	* Routed URI to assoc
	*
	* Identical to CI_URI::uri_to_assoc(), only it uses the re-routed
	* segment array.
	*
	* @see CI_URI::uri_to_assoc()
	* @param int $n Index (default: 3)
	* @param array $default Default values
	* @return array
	*/
	public function ruri_to_assoc($n = 3, $default = array())
	{
	return $this->_uri_to_assoc($n, $default, 'rsegment');
	}

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

	/**
	* Internal URI-to-assoc
	*
	* Generates a key/value pair from the URI string or re-routed URI string.
	*
	* @used-by CI_URI::uri_to_assoc()
	* @used-by CI_URI::ruri_to_assoc()
	* @param int $n Index (default: 3)
	* @param array $default Default values
	* @param string $which Array name ('segment' or 'rsegment')
	* @return array
	*/
	protected function _uri_to_assoc($n = 3, $default = array(), $which = 'segment')
	{
	if ( ! is_numeric($n))
	{
	return $default;
	}

	if (isset($this->keyval[$which], $this->keyval[$which][$n]))
	{
	return $this->keyval[$which][$n];
	}

	$total_segments = "total_{$which}s";
	$segment_array = "{$which}_array";

	if ($this->$total_segments() < $n)
	{
	return (count($default) === 0)
	? array()
	: array_fill_keys($default, NULL);
	}

	$segments = array_slice($this->$segment_array(), ($n - 1));
	$i = 0;
	$lastval = '';
	$retval = array();
	foreach ($segments as $seg)
	{
	if ($i % 2)
	{
	$retval[$lastval] = $seg;
	}
	else
	{
	$retval[$seg] = NULL;
	$lastval = $seg;
	}

	$i++;
	}

	if (count($default) > 0)
	{
	foreach ($default as $val)
	{
	if ( ! array_key_exists($val, $retval))
	{
	$retval[$val] = NULL;
	}
	}
	}

	// Cache the array for reuse
	isset($this->keyval[$which]) OR $this->keyval[$which] = array();
	$this->keyval[$which][$n] = $retval;
	return $retval;
	}

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

	/**
	* Assoc to URI
	*
	* Generates a URI string from an associative array.
	*
	* @param array $array Input array of key/value pairs
	* @return string URI string
	*/
	public function assoc_to_uri($array)
	{
	$temp = array();
	foreach ((array) $array as $key => $val)
	{
	$temp[] = $key;
	$temp[] = $val;
	}

	return implode('/', $temp);
	}

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

	/**
	* Slash segment
	*
	* Fetches an URI segment with a slash.
	*
	* @param int $n Index
	* @param string $where Where to add the slash ('trailing' or 'leading')
	* @return string
	*/
	public function slash_segment($n, $where = 'trailing')
	{
	return $this->_slash_segment($n, $where, 'segment');
	}

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

	/**
	* Slash routed segment
	*
	* Fetches an URI routed segment with a slash.
	*
	* @param int $n Index
	* @param string $where Where to add the slash ('trailing' or 'leading')
	* @return string
	*/
	public function slash_rsegment($n, $where = 'trailing')
	{
	return $this->_slash_segment($n, $where, 'rsegment');
	}

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

	/**
	* Internal Slash segment
	*
	* Fetches an URI Segment and adds a slash to it.
	*
	* @used-by CI_URI::slash_segment()
	* @used-by CI_URI::slash_rsegment()
	*
	* @param int $n Index
	* @param string $where Where to add the slash ('trailing' or 'leading')
	* @param string $which Array name ('segment' or 'rsegment')
	* @return string
	*/
	protected function _slash_segment($n, $where = 'trailing', $which = 'segment')
	{
	$leading = $trailing = '/';

	if ($where === 'trailing')
	{
	$leading = '';
	}
	elseif ($where === 'leading')
	{
	$trailing = '';
	}

	return $leading.$this->$which($n).$trailing;
	}

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

	/**
	* Segment Array
	*
	* @return array CI_URI::$segments
	*/
	public function segment_array()
	{
	return $this->segments;
	}

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

	/**
	* Routed Segment Array
	*
	* @return array CI_URI::$rsegments
	*/
	public function rsegment_array()
	{
	return $this->rsegments;
	}

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

	/**
	* Total number of segments
	*
	* @return int
	*/
	public function total_segments()
	{
	return count($this->segments);
	}

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

	/**
	* Total number of routed segments
	*
	* @return int
	*/
	public function total_rsegments()
	{
	return count($this->rsegments);
	}

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

	/**
	* Fetch URI string
	*
	* @return string CI_URI::$uri_string
	*/
	public function uri_string()
	{
	return $this->uri_string;
	}

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

	/**
	* Fetch Re-routed URI string
	*
	* @return string
	*/
	public function ruri_string()
	{
	return ltrim(load_class('Router', 'core')->directory, '/').implode('/', $this->rsegments);
	}

	}