angelovcom.net

IRI.php (28553B)

---

 <?php
 /**
  * IRI parser/serialiser/normaliser
  *
  * @package Requests
  * @subpackage Utilities
  */
 
 /**
  * IRI parser/serialiser/normaliser
  *
  * Copyright (c) 2007-2010, Geoffrey Sneddon and Steve Minutillo.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  *  * Redistributions of source code must retain the above copyright notice,
  *       this list of conditions and the following disclaimer.
  *
  *  * Redistributions in binary form must reproduce the above copyright notice,
  *       this list of conditions and the following disclaimer in the documentation
  *       and/or other materials provided with the distribution.
  *
  *  * Neither the name of the SimplePie Team nor the names of its contributors
  *       may be used to endorse or promote products derived from this software
  *       without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS AND CONTRIBUTORS BE
  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  *
  * @package Requests
  * @subpackage Utilities
  * @author Geoffrey Sneddon
  * @author Steve Minutillo
  * @copyright 2007-2009 Geoffrey Sneddon and Steve Minutillo
  * @license http://www.opensource.org/licenses/bsd-license.php
  * @link http://hg.gsnedders.com/iri/
  *
  * @property string $iri IRI we're working with
  * @property-read string $uri IRI in URI form, {@see to_uri}
  * @property string $scheme Scheme part of the IRI
  * @property string $authority Authority part, formatted for a URI (userinfo + host + port)
  * @property string $iauthority Authority part of the IRI (userinfo + host + port)
  * @property string $userinfo Userinfo part, formatted for a URI (after '://' and before '@')
  * @property string $iuserinfo Userinfo part of the IRI (after '://' and before '@')
  * @property string $host Host part, formatted for a URI
  * @property string $ihost Host part of the IRI
  * @property string $port Port part of the IRI (after ':')
  * @property string $path Path part, formatted for a URI (after first '/')
  * @property string $ipath Path part of the IRI (after first '/')
  * @property string $query Query part, formatted for a URI (after '?')
  * @property string $iquery Query part of the IRI (after '?')
  * @property string $fragment Fragment, formatted for a URI (after '#')
  * @property string $ifragment Fragment part of the IRI (after '#')
  */
 class Requests_IRI {
 	/**
 	 * Scheme
 	 *
 	 * @var string|null
 	 */
 	protected $scheme = null;
 
 	/**
 	 * User Information
 	 *
 	 * @var string|null
 	 */
 	protected $iuserinfo = null;
 
 	/**
 	 * ihost
 	 *
 	 * @var string|null
 	 */
 	protected $ihost = null;
 
 	/**
 	 * Port
 	 *
 	 * @var string|null
 	 */
 	protected $port = null;
 
 	/**
 	 * ipath
 	 *
 	 * @var string
 	 */
 	protected $ipath = '';
 
 	/**
 	 * iquery
 	 *
 	 * @var string|null
 	 */
 	protected $iquery = null;
 
 	/**
 	 * ifragment|null
 	 *
 	 * @var string
 	 */
 	protected $ifragment = null;
 
 	/**
 	 * Normalization database
 	 *
 	 * Each key is the scheme, each value is an array with each key as the IRI
 	 * part and value as the default value for that part.
 	 *
 	 * @var array
 	 */
 	protected $normalization = array(
 		'acap' => array(
 			'port' => 674
 		),
 		'dict' => array(
 			'port' => 2628
 		),
 		'file' => array(
 			'ihost' => 'localhost'
 		),
 		'http' => array(
 			'port' => 80,
 		),
 		'https' => array(
 			'port' => 443,
 		),
 	);
 
 	/**
 	 * Return the entire IRI when you try and read the object as a string
 	 *
 	 * @return string
 	 */
 	public function __toString() {
 		return $this->get_iri();
 	}
 
 	/**
 	 * Overload __set() to provide access via properties
 	 *
 	 * @param string $name Property name
 	 * @param mixed $value Property value
 	 */
 	public function __set($name, $value) {
 		if (method_exists($this, 'set_' . $name)) {
 			call_user_func(array($this, 'set_' . $name), $value);
 		}
 		elseif (
 			   $name === 'iauthority'
 			|| $name === 'iuserinfo'
 			|| $name === 'ihost'
 			|| $name === 'ipath'
 			|| $name === 'iquery'
 			|| $name === 'ifragment'
 		) {
 			call_user_func(array($this, 'set_' . substr($name, 1)), $value);
 		}
 	}
 
 	/**
 	 * Overload __get() to provide access via properties
 	 *
 	 * @param string $name Property name
 	 * @return mixed
 	 */
 	public function __get($name) {
 		// isset() returns false for null, we don't want to do that
 		// Also why we use array_key_exists below instead of isset()
 		$props = get_object_vars($this);
 
 		if (
 			$name === 'iri' ||
 			$name === 'uri' ||
 			$name === 'iauthority' ||
 			$name === 'authority'
 		) {
 			$method = 'get_' . $name;
 			$return = $this->$method();
 		}
 		elseif (array_key_exists($name, $props)) {
 			$return = $this->$name;
 		}
 		// host -> ihost
 		elseif (($prop = 'i' . $name) && array_key_exists($prop, $props)) {
 			$name = $prop;
 			$return = $this->$prop;
 		}
 		// ischeme -> scheme
 		elseif (($prop = substr($name, 1)) && array_key_exists($prop, $props)) {
 			$name = $prop;
 			$return = $this->$prop;
 		}
 		else {
 			trigger_error('Undefined property: ' . get_class($this) . '::' . $name, E_USER_NOTICE);
 			$return = null;
 		}
 
 		if ($return === null && isset($this->normalization[$this->scheme][$name])) {
 			return $this->normalization[$this->scheme][$name];
 		}
 		else {
 			return $return;
 		}
 	}
 
 	/**
 	 * Overload __isset() to provide access via properties
 	 *
 	 * @param string $name Property name
 	 * @return bool
 	 */
 	public function __isset($name) {
 		return (method_exists($this, 'get_' . $name) || isset($this->$name));
 	}
 
 	/**
 	 * Overload __unset() to provide access via properties
 	 *
 	 * @param string $name Property name
 	 */
 	public function __unset($name) {
 		if (method_exists($this, 'set_' . $name)) {
 			call_user_func(array($this, 'set_' . $name), '');
 		}
 	}
 
 	/**
 	 * Create a new IRI object, from a specified string
 	 *
 	 * @param string|null $iri
 	 */
 	public function __construct($iri = null) {
 		$this->set_iri($iri);
 	}
 
 	/**
 	 * Create a new IRI object by resolving a relative IRI
 	 *
 	 * Returns false if $base is not absolute, otherwise an IRI.
 	 *
 	 * @param Requests_IRI|string $base (Absolute) Base IRI
 	 * @param Requests_IRI|string $relative Relative IRI
 	 * @return Requests_IRI|false
 	 */
 	public static function absolutize($base, $relative) {
 		if (!($relative instanceof Requests_IRI)) {
 			$relative = new Requests_IRI($relative);
 		}
 		if (!$relative->is_valid()) {
 			return false;
 		}
 		elseif ($relative->scheme !== null) {
 			return clone $relative;
 		}
 
 		if (!($base instanceof Requests_IRI)) {
 			$base = new Requests_IRI($base);
 		}
 		if ($base->scheme === null || !$base->is_valid()) {
 			return false;
 		}
 
 		if ($relative->get_iri() !== '') {
 			if ($relative->iuserinfo !== null || $relative->ihost !== null || $relative->port !== null) {
 				$target = clone $relative;
 				$target->scheme = $base->scheme;
 			}
 			else {
 				$target = new Requests_IRI;
 				$target->scheme = $base->scheme;
 				$target->iuserinfo = $base->iuserinfo;
 				$target->ihost = $base->ihost;
 				$target->port = $base->port;
 				if ($relative->ipath !== '') {
 					if ($relative->ipath[0] === '/') {
 						$target->ipath = $relative->ipath;
 					}
 					elseif (($base->iuserinfo !== null || $base->ihost !== null || $base->port !== null) && $base->ipath === '') {
 						$target->ipath = '/' . $relative->ipath;
 					}
 					elseif (($last_segment = strrpos($base->ipath, '/')) !== false) {
 						$target->ipath = substr($base->ipath, 0, $last_segment + 1) . $relative->ipath;
 					}
 					else {
 						$target->ipath = $relative->ipath;
 					}
 					$target->ipath = $target->remove_dot_segments($target->ipath);
 					$target->iquery = $relative->iquery;
 				}
 				else {
 					$target->ipath = $base->ipath;
 					if ($relative->iquery !== null) {
 						$target->iquery = $relative->iquery;
 					}
 					elseif ($base->iquery !== null) {
 						$target->iquery = $base->iquery;
 					}
 				}
 				$target->ifragment = $relative->ifragment;
 			}
 		}
 		else {
 			$target = clone $base;
 			$target->ifragment = null;
 		}
 		$target->scheme_normalization();
 		return $target;
 	}
 
 	/**
 	 * Parse an IRI into scheme/authority/path/query/fragment segments
 	 *
 	 * @param string $iri
 	 * @return array
 	 */
 	protected function parse_iri($iri) {
 		$iri = trim($iri, "\x20\x09\x0A\x0C\x0D");
 		$has_match = preg_match('/^((?P<scheme>[^:\/?#]+):)?(\/\/(?P<authority>[^\/?#]*))?(?P<path>[^?#]*)(\?(?P<query>[^#]*))?(#(?P<fragment>.*))?$/', $iri, $match);
 		if (!$has_match) {
 			throw new Requests_Exception('Cannot parse supplied IRI', 'iri.cannot_parse', $iri);
 		}
 
 		if ($match[1] === '') {
 			$match['scheme'] = null;
 		}
 		if (!isset($match[3]) || $match[3] === '') {
 			$match['authority'] = null;
 		}
 		if (!isset($match[5])) {
 			$match['path'] = '';
 		}
 		if (!isset($match[6]) || $match[6] === '') {
 			$match['query'] = null;
 		}
 		if (!isset($match[8]) || $match[8] === '') {
 			$match['fragment'] = null;
 		}
 		return $match;
 	}
 
 	/**
 	 * Remove dot segments from a path
 	 *
 	 * @param string $input
 	 * @return string
 	 */
 	protected function remove_dot_segments($input) {
 		$output = '';
 		while (strpos($input, './') !== false || strpos($input, '/.') !== false || $input === '.' || $input === '..') {
 			// A: If the input buffer begins with a prefix of "../" or "./",
 			// then remove that prefix from the input buffer; otherwise,
 			if (strpos($input, '../') === 0) {
 				$input = substr($input, 3);
 			}
 			elseif (strpos($input, './') === 0) {
 				$input = substr($input, 2);
 			}
 			// B: if the input buffer begins with a prefix of "/./" or "/.",
 			// where "." is a complete path segment, then replace that prefix
 			// with "/" in the input buffer; otherwise,
 			elseif (strpos($input, '/./') === 0) {
 				$input = substr($input, 2);
 			}
 			elseif ($input === '/.') {
 				$input = '/';
 			}
 			// C: if the input buffer begins with a prefix of "/../" or "/..",
 			// where ".." is a complete path segment, then replace that prefix
 			// with "/" in the input buffer and remove the last segment and its
 			// preceding "/" (if any) from the output buffer; otherwise,
 			elseif (strpos($input, '/../') === 0) {
 				$input = substr($input, 3);
 				$output = substr_replace($output, '', strrpos($output, '/'));
 			}
 			elseif ($input === '/..') {
 				$input = '/';
 				$output = substr_replace($output, '', strrpos($output, '/'));
 			}
 			// D: if the input buffer consists only of "." or "..", then remove
 			// that from the input buffer; otherwise,
 			elseif ($input === '.' || $input === '..') {
 				$input = '';
 			}
 			// E: move the first path segment in the input buffer to the end of
 			// the output buffer, including the initial "/" character (if any)
 			// and any subsequent characters up to, but not including, the next
 			// "/" character or the end of the input buffer
 			elseif (($pos = strpos($input, '/', 1)) !== false) {
 				$output .= substr($input, 0, $pos);
 				$input = substr_replace($input, '', 0, $pos);
 			}
 			else {
 				$output .= $input;
 				$input = '';
 			}
 		}
 		return $output . $input;
 	}
 
 	/**
 	 * Replace invalid character with percent encoding
 	 *
 	 * @param string $string Input string
 	 * @param string $extra_chars Valid characters not in iunreserved or
 	 *                            iprivate (this is ASCII-only)
 	 * @param bool $iprivate Allow iprivate
 	 * @return string
 	 */
 	protected function replace_invalid_with_pct_encoding($string, $extra_chars, $iprivate = false) {
 		// Normalize as many pct-encoded sections as possible
 		$string = preg_replace_callback('/(?:%[A-Fa-f0-9]{2})+/', array($this, 'remove_iunreserved_percent_encoded'), $string);
 
 		// Replace invalid percent characters
 		$string = preg_replace('/%(?![A-Fa-f0-9]{2})/', '%25', $string);
 
 		// Add unreserved and % to $extra_chars (the latter is safe because all
 		// pct-encoded sections are now valid).
 		$extra_chars .= 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-._~%';
 
 		// Now replace any bytes that aren't allowed with their pct-encoded versions
 		$position = 0;
 		$strlen = strlen($string);
 		while (($position += strspn($string, $extra_chars, $position)) < $strlen) {
 			$value = ord($string[$position]);
 
 			// Start position
 			$start = $position;
 
 			// By default we are valid
 			$valid = true;
 
 			// No one byte sequences are valid due to the while.
 			// Two byte sequence:
 			if (($value & 0xE0) === 0xC0) {
 				$character = ($value & 0x1F) << 6;
 				$length = 2;
 				$remaining = 1;
 			}
 			// Three byte sequence:
 			elseif (($value & 0xF0) === 0xE0) {
 				$character = ($value & 0x0F) << 12;
 				$length = 3;
 				$remaining = 2;
 			}
 			// Four byte sequence:
 			elseif (($value & 0xF8) === 0xF0) {
 				$character = ($value & 0x07) << 18;
 				$length = 4;
 				$remaining = 3;
 			}
 			// Invalid byte:
 			else {
 				$valid = false;
 				$length = 1;
 				$remaining = 0;
 			}
 
 			if ($remaining) {
 				if ($position + $length <= $strlen) {
 					for ($position++; $remaining; $position++) {
 						$value = ord($string[$position]);
 
 						// Check that the byte is valid, then add it to the character:
 						if (($value & 0xC0) === 0x80) {
 							$character |= ($value & 0x3F) << (--$remaining * 6);
 						}
 						// If it is invalid, count the sequence as invalid and reprocess the current byte:
 						else {
 							$valid = false;
 							$position--;
 							break;
 						}
 					}
 				}
 				else {
 					$position = $strlen - 1;
 					$valid = false;
 				}
 			}
 
 			// Percent encode anything invalid or not in ucschar
 			if (
 				// Invalid sequences
 				!$valid
 				// Non-shortest form sequences are invalid
 				|| $length > 1 && $character <= 0x7F
 				|| $length > 2 && $character <= 0x7FF
 				|| $length > 3 && $character <= 0xFFFF
 				// Outside of range of ucschar codepoints
 				// Noncharacters
 				|| ($character & 0xFFFE) === 0xFFFE
 				|| $character >= 0xFDD0 && $character <= 0xFDEF
 				|| (
 					// Everything else not in ucschar
 					   $character > 0xD7FF && $character < 0xF900
 					|| $character < 0xA0
 					|| $character > 0xEFFFD
 				)
 				&& (
 					// Everything not in iprivate, if it applies
 					   !$iprivate
 					|| $character < 0xE000
 					|| $character > 0x10FFFD
 				)
 			) {
 				// If we were a character, pretend we weren't, but rather an error.
 				if ($valid) {
 					$position--;
 				}
 
 				for ($j = $start; $j <= $position; $j++) {
 					$string = substr_replace($string, sprintf('%%%02X', ord($string[$j])), $j, 1);
 					$j += 2;
 					$position += 2;
 					$strlen += 2;
 				}
 			}
 		}
 
 		return $string;
 	}
 
 	/**
 	 * Callback function for preg_replace_callback.
 	 *
 	 * Removes sequences of percent encoded bytes that represent UTF-8
 	 * encoded characters in iunreserved
 	 *
 	 * @param array $match PCRE match
 	 * @return string Replacement
 	 */
 	protected function remove_iunreserved_percent_encoded($match) {
 		// As we just have valid percent encoded sequences we can just explode
 		// and ignore the first member of the returned array (an empty string).
 		$bytes = explode('%', $match[0]);
 
 		// Initialize the new string (this is what will be returned) and that
 		// there are no bytes remaining in the current sequence (unsurprising
 		// at the first byte!).
 		$string = '';
 		$remaining = 0;
 
 		// Loop over each and every byte, and set $value to its value
 		for ($i = 1, $len = count($bytes); $i < $len; $i++) {
 			$value = hexdec($bytes[$i]);
 
 			// If we're the first byte of sequence:
 			if (!$remaining) {
 				// Start position
 				$start = $i;
 
 				// By default we are valid
 				$valid = true;
 
 				// One byte sequence:
 				if ($value <= 0x7F) {
 					$character = $value;
 					$length = 1;
 				}
 				// Two byte sequence:
 				elseif (($value & 0xE0) === 0xC0) {
 					$character = ($value & 0x1F) << 6;
 					$length = 2;
 					$remaining = 1;
 				}
 				// Three byte sequence:
 				elseif (($value & 0xF0) === 0xE0) {
 					$character = ($value & 0x0F) << 12;
 					$length = 3;
 					$remaining = 2;
 				}
 				// Four byte sequence:
 				elseif (($value & 0xF8) === 0xF0) {
 					$character = ($value & 0x07) << 18;
 					$length = 4;
 					$remaining = 3;
 				}
 				// Invalid byte:
 				else {
 					$valid = false;
 					$remaining = 0;
 				}
 			}
 			// Continuation byte:
 			else {
 				// Check that the byte is valid, then add it to the character:
 				if (($value & 0xC0) === 0x80) {
 					$remaining--;
 					$character |= ($value & 0x3F) << ($remaining * 6);
 				}
 				// If it is invalid, count the sequence as invalid and reprocess the current byte as the start of a sequence:
 				else {
 					$valid = false;
 					$remaining = 0;
 					$i--;
 				}
 			}
 
 			// If we've reached the end of the current byte sequence, append it to Unicode::$data
 			if (!$remaining) {
 				// Percent encode anything invalid or not in iunreserved
 				if (
 					// Invalid sequences
 					!$valid
 					// Non-shortest form sequences are invalid
 					|| $length > 1 && $character <= 0x7F
 					|| $length > 2 && $character <= 0x7FF
 					|| $length > 3 && $character <= 0xFFFF
 					// Outside of range of iunreserved codepoints
 					|| $character < 0x2D
 					|| $character > 0xEFFFD
 					// Noncharacters
 					|| ($character & 0xFFFE) === 0xFFFE
 					|| $character >= 0xFDD0 && $character <= 0xFDEF
 					// Everything else not in iunreserved (this is all BMP)
 					|| $character === 0x2F
 					|| $character > 0x39 && $character < 0x41
 					|| $character > 0x5A && $character < 0x61
 					|| $character > 0x7A && $character < 0x7E
 					|| $character > 0x7E && $character < 0xA0
 					|| $character > 0xD7FF && $character < 0xF900
 				) {
 					for ($j = $start; $j <= $i; $j++) {
 						$string .= '%' . strtoupper($bytes[$j]);
 					}
 				}
 				else {
 					for ($j = $start; $j <= $i; $j++) {
 						$string .= chr(hexdec($bytes[$j]));
 					}
 				}
 			}
 		}
 
 		// If we have any bytes left over they are invalid (i.e., we are
 		// mid-way through a multi-byte sequence)
 		if ($remaining) {
 			for ($j = $start; $j < $len; $j++) {
 				$string .= '%' . strtoupper($bytes[$j]);
 			}
 		}
 
 		return $string;
 	}
 
 	protected function scheme_normalization() {
 		if (isset($this->normalization[$this->scheme]['iuserinfo']) && $this->iuserinfo === $this->normalization[$this->scheme]['iuserinfo']) {
 			$this->iuserinfo = null;
 		}
 		if (isset($this->normalization[$this->scheme]['ihost']) && $this->ihost === $this->normalization[$this->scheme]['ihost']) {
 			$this->ihost = null;
 		}
 		if (isset($this->normalization[$this->scheme]['port']) && $this->port === $this->normalization[$this->scheme]['port']) {
 			$this->port = null;
 		}
 		if (isset($this->normalization[$this->scheme]['ipath']) && $this->ipath === $this->normalization[$this->scheme]['ipath']) {
 			$this->ipath = '';
 		}
 		if (isset($this->ihost) && empty($this->ipath)) {
 			$this->ipath = '/';
 		}
 		if (isset($this->normalization[$this->scheme]['iquery']) && $this->iquery === $this->normalization[$this->scheme]['iquery']) {
 			$this->iquery = null;
 		}
 		if (isset($this->normalization[$this->scheme]['ifragment']) && $this->ifragment === $this->normalization[$this->scheme]['ifragment']) {
 			$this->ifragment = null;
 		}
 	}
 
 	/**
 	 * Check if the object represents a valid IRI. This needs to be done on each
 	 * call as some things change depending on another part of the IRI.
 	 *
 	 * @return bool
 	 */
 	public function is_valid() {
 		$isauthority = $this->iuserinfo !== null || $this->ihost !== null || $this->port !== null;
 		if ($this->ipath !== '' &&
 			(
 				$isauthority && $this->ipath[0] !== '/' ||
 				(
 					$this->scheme === null &&
 					!$isauthority &&
 					strpos($this->ipath, ':') !== false &&
 					(strpos($this->ipath, '/') === false ? true : strpos($this->ipath, ':') < strpos($this->ipath, '/'))
 				)
 			)
 		) {
 			return false;
 		}
 
 		return true;
 	}
 
 	/**
 	 * Set the entire IRI. Returns true on success, false on failure (if there
 	 * are any invalid characters).
 	 *
 	 * @param string $iri
 	 * @return bool
 	 */
 	protected function set_iri($iri) {
 		static $cache;
 		if (!$cache) {
 			$cache = array();
 		}
 
 		if ($iri === null) {
 			return true;
 		}
 		if (isset($cache[$iri])) {
 			list($this->scheme,
 				 $this->iuserinfo,
 				 $this->ihost,
 				 $this->port,
 				 $this->ipath,
 				 $this->iquery,
 				 $this->ifragment,
 				 $return) = $cache[$iri];
 			return $return;
 		}
 
 		$parsed = $this->parse_iri((string) $iri);
 
 		$return = $this->set_scheme($parsed['scheme'])
 			&& $this->set_authority($parsed['authority'])
 			&& $this->set_path($parsed['path'])
 			&& $this->set_query($parsed['query'])
 			&& $this->set_fragment($parsed['fragment']);
 
 		$cache[$iri] = array($this->scheme,
 							 $this->iuserinfo,
 							 $this->ihost,
 							 $this->port,
 							 $this->ipath,
 							 $this->iquery,
 							 $this->ifragment,
 							 $return);
 		return $return;
 	}
 
 	/**
 	 * Set the scheme. Returns true on success, false on failure (if there are
 	 * any invalid characters).
 	 *
 	 * @param string $scheme
 	 * @return bool
 	 */
 	protected function set_scheme($scheme) {
 		if ($scheme === null) {
 			$this->scheme = null;
 		}
 		elseif (!preg_match('/^[A-Za-z][0-9A-Za-z+\-.]*$/', $scheme)) {
 			$this->scheme = null;
 			return false;
 		}
 		else {
 			$this->scheme = strtolower($scheme);
 		}
 		return true;
 	}
 
 	/**
 	 * Set the authority. Returns true on success, false on failure (if there are
 	 * any invalid characters).
 	 *
 	 * @param string $authority
 	 * @return bool
 	 */
 	protected function set_authority($authority) {
 		static $cache;
 		if (!$cache) {
 			$cache = array();
 		}
 
 		if ($authority === null) {
 			$this->iuserinfo = null;
 			$this->ihost = null;
 			$this->port = null;
 			return true;
 		}
 		if (isset($cache[$authority])) {
 			list($this->iuserinfo,
 				 $this->ihost,
 				 $this->port,
 				 $return) = $cache[$authority];
 
 			return $return;
 		}
 
 		$remaining = $authority;
 		if (($iuserinfo_end = strrpos($remaining, '@')) !== false) {
 			$iuserinfo = substr($remaining, 0, $iuserinfo_end);
 			$remaining = substr($remaining, $iuserinfo_end + 1);
 		}
 		else {
 			$iuserinfo = null;
 		}
 		if (($port_start = strpos($remaining, ':', strpos($remaining, ']'))) !== false) {
 			$port = substr($remaining, $port_start + 1);
 			if ($port === false || $port === '') {
 				$port = null;
 			}
 			$remaining = substr($remaining, 0, $port_start);
 		}
 		else {
 			$port = null;
 		}
 
 		$return = $this->set_userinfo($iuserinfo) &&
 				  $this->set_host($remaining) &&
 				  $this->set_port($port);
 
 		$cache[$authority] = array($this->iuserinfo,
 								   $this->ihost,
 								   $this->port,
 								   $return);
 
 		return $return;
 	}
 
 	/**
 	 * Set the iuserinfo.
 	 *
 	 * @param string $iuserinfo
 	 * @return bool
 	 */
 	protected function set_userinfo($iuserinfo) {
 		if ($iuserinfo === null) {
 			$this->iuserinfo = null;
 		}
 		else {
 			$this->iuserinfo = $this->replace_invalid_with_pct_encoding($iuserinfo, '!$&\'()*+,;=:');
 			$this->scheme_normalization();
 		}
 
 		return true;
 	}
 
 	/**
 	 * Set the ihost. Returns true on success, false on failure (if there are
 	 * any invalid characters).
 	 *
 	 * @param string $ihost
 	 * @return bool
 	 */
 	protected function set_host($ihost) {
 		if ($ihost === null) {
 			$this->ihost = null;
 			return true;
 		}
 		if (substr($ihost, 0, 1) === '[' && substr($ihost, -1) === ']') {
 			if (Requests_IPv6::check_ipv6(substr($ihost, 1, -1))) {
 				$this->ihost = '[' . Requests_IPv6::compress(substr($ihost, 1, -1)) . ']';
 			}
 			else {
 				$this->ihost = null;
 				return false;
 			}
 		}
 		else {
 			$ihost = $this->replace_invalid_with_pct_encoding($ihost, '!$&\'()*+,;=');
 
 			// Lowercase, but ignore pct-encoded sections (as they should
 			// remain uppercase). This must be done after the previous step
 			// as that can add unescaped characters.
 			$position = 0;
 			$strlen = strlen($ihost);
 			while (($position += strcspn($ihost, 'ABCDEFGHIJKLMNOPQRSTUVWXYZ%', $position)) < $strlen) {
 				if ($ihost[$position] === '%') {
 					$position += 3;
 				}
 				else {
 					$ihost[$position] = strtolower($ihost[$position]);
 					$position++;
 				}
 			}
 
 			$this->ihost = $ihost;
 		}
 
 		$this->scheme_normalization();
 
 		return true;
 	}
 
 	/**
 	 * Set the port. Returns true on success, false on failure (if there are
 	 * any invalid characters).
 	 *
 	 * @param string $port
 	 * @return bool
 	 */
 	protected function set_port($port) {
 		if ($port === null) {
 			$this->port = null;
 			return true;
 		}
 
 		if (strspn($port, '0123456789') === strlen($port)) {
 			$this->port = (int) $port;
 			$this->scheme_normalization();
 			return true;
 		}
 
 		$this->port = null;
 		return false;
 	}
 
 	/**
 	 * Set the ipath.
 	 *
 	 * @param string $ipath
 	 * @return bool
 	 */
 	protected function set_path($ipath) {
 		static $cache;
 		if (!$cache) {
 			$cache = array();
 		}
 
 		$ipath = (string) $ipath;
 
 		if (isset($cache[$ipath])) {
 			$this->ipath = $cache[$ipath][(int) ($this->scheme !== null)];
 		}
 		else {
 			$valid = $this->replace_invalid_with_pct_encoding($ipath, '!$&\'()*+,;=@:/');
 			$removed = $this->remove_dot_segments($valid);
 
 			$cache[$ipath] = array($valid, $removed);
 			$this->ipath = ($this->scheme !== null) ? $removed : $valid;
 		}
 		$this->scheme_normalization();
 		return true;
 	}
 
 	/**
 	 * Set the iquery.
 	 *
 	 * @param string $iquery
 	 * @return bool
 	 */
 	protected function set_query($iquery) {
 		if ($iquery === null) {
 			$this->iquery = null;
 		}
 		else {
 			$this->iquery = $this->replace_invalid_with_pct_encoding($iquery, '!$&\'()*+,;=:@/?', true);
 			$this->scheme_normalization();
 		}
 		return true;
 	}
 
 	/**
 	 * Set the ifragment.
 	 *
 	 * @param string $ifragment
 	 * @return bool
 	 */
 	protected function set_fragment($ifragment) {
 		if ($ifragment === null) {
 			$this->ifragment = null;
 		}
 		else {
 			$this->ifragment = $this->replace_invalid_with_pct_encoding($ifragment, '!$&\'()*+,;=:@/?');
 			$this->scheme_normalization();
 		}
 		return true;
 	}
 
 	/**
 	 * Convert an IRI to a URI (or parts thereof)
 	 *
 	 * @param string|bool IRI to convert (or false from {@see get_iri})
 	 * @return string|false URI if IRI is valid, false otherwise.
 	 */
 	protected function to_uri($string) {
 		if (!is_string($string)) {
 			return false;
 		}
 
 		static $non_ascii;
 		if (!$non_ascii) {
 			$non_ascii = implode('', range("\x80", "\xFF"));
 		}
 
 		$position = 0;
 		$strlen = strlen($string);
 		while (($position += strcspn($string, $non_ascii, $position)) < $strlen) {
 			$string = substr_replace($string, sprintf('%%%02X', ord($string[$position])), $position, 1);
 			$position += 3;
 			$strlen += 2;
 		}
 
 		return $string;
 	}
 
 	/**
 	 * Get the complete IRI
 	 *
 	 * @return string|false
 	 */
 	protected function get_iri() {
 		if (!$this->is_valid()) {
 			return false;
 		}
 
 		$iri = '';
 		if ($this->scheme !== null) {
 			$iri .= $this->scheme . ':';
 		}
 		if (($iauthority = $this->get_iauthority()) !== null) {
 			$iri .= '//' . $iauthority;
 		}
 		$iri .= $this->ipath;
 		if ($this->iquery !== null) {
 			$iri .= '?' . $this->iquery;
 		}
 		if ($this->ifragment !== null) {
 			$iri .= '#' . $this->ifragment;
 		}
 
 		return $iri;
 	}
 
 	/**
 	 * Get the complete URI
 	 *
 	 * @return string
 	 */
 	protected function get_uri() {
 		return $this->to_uri($this->get_iri());
 	}
 
 	/**
 	 * Get the complete iauthority
 	 *
 	 * @return string|null
 	 */
 	protected function get_iauthority() {
 		if ($this->iuserinfo === null && $this->ihost === null && $this->port === null) {
 			return null;
 		}
 
 		$iauthority = '';
 		if ($this->iuserinfo !== null) {
 			$iauthority .= $this->iuserinfo . '@';
 		}
 		if ($this->ihost !== null) {
 			$iauthority .= $this->ihost;
 		}
 		if ($this->port !== null) {
 			$iauthority .= ':' . $this->port;
 		}
 		return $iauthority;
 	}
 
 	/**
 	 * Get the complete authority
 	 *
 	 * @return string
 	 */
 	protected function get_authority() {
 		$iauthority = $this->get_iauthority();
 		if (is_string($iauthority)) {
 			return $this->to_uri($iauthority);
 		}
 		else {
 			return $iauthority;
 		}
 	}
 }