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[autoinstalls/wordpress.git] / wp-includes / Requests / IRI.php
diff --git a/wp-includes/Requests/IRI.php b/wp-includes/Requests/IRI.php
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+<?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
+        */
+       protected $scheme = null;
+
+       /**
+        * User Information
+        *
+        * @var string
+        */
+       protected $iuserinfo = null;
+
+       /**
+        * ihost
+        *
+        * @var string
+        */
+       protected $ihost = null;
+
+       /**
+        * Port
+        *
+        * @var string
+        */
+       protected $port = null;
+
+       /**
+        * ipath
+        *
+        * @var string
+        */
+       protected $ipath = '';
+
+       /**
+        * iquery
+        *
+        * @var string
+        */
+       protected $iquery = null;
+
+       /**
+        * ifragment
+        *
+        * @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.
+        */
+       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 IRI|string $base (Absolute) Base IRI
+        * @param IRI|string $relative Relative IRI
+        * @return IRI|false
+        */
+       public static function absolutize($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 && (
+                                       $this->ipath[0] !== '/' ||
+                                       substr($this->ipath, 0, 2) === '//'
+                               ) ||
+                               (
+                                       $this->scheme === null &&
+                                       !$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 $string;
+       }
+
+       /**
+        * Get the complete IRI
+        *
+        * @return string
+        */
+       protected function get_iri() {
+               if (!$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
+        */
+       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;
+               }
+       }
+}