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   1  <?php
   2  /**
   3   * IRI parser/serialiser/normaliser
   4   *
   5   * @package Requests
   6   * @subpackage Utilities
   7   */
   8  
   9  /**
  10   * IRI parser/serialiser/normaliser
  11   *
  12   * Copyright (c) 2007-2010, Geoffrey Sneddon and Steve Minutillo.
  13   * All rights reserved.
  14   *
  15   * Redistribution and use in source and binary forms, with or without
  16   * modification, are permitted provided that the following conditions are met:
  17   *
  18   *  * Redistributions of source code must retain the above copyright notice,
  19   *       this list of conditions and the following disclaimer.
  20   *
  21   *  * Redistributions in binary form must reproduce the above copyright notice,
  22   *       this list of conditions and the following disclaimer in the documentation
  23   *       and/or other materials provided with the distribution.
  24   *
  25   *  * Neither the name of the SimplePie Team nor the names of its contributors
  26   *       may be used to endorse or promote products derived from this software
  27   *       without specific prior written permission.
  28   *
  29   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  30   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  31   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  32   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS AND CONTRIBUTORS BE
  33   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  34   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  35   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  36   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  37   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  38   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  39   * POSSIBILITY OF SUCH DAMAGE.
  40   *
  41   * @package Requests
  42   * @subpackage Utilities
  43   * @author Geoffrey Sneddon
  44   * @author Steve Minutillo
  45   * @copyright 2007-2009 Geoffrey Sneddon and Steve Minutillo
  46   * @license http://www.opensource.org/licenses/bsd-license.php
  47   * @link http://hg.gsnedders.com/iri/
  48   *
  49   * @property string $iri IRI we're working with
  50   * @property-read string $uri IRI in URI form, {@see to_uri}
  51   * @property string $scheme Scheme part of the IRI
  52   * @property string $authority Authority part, formatted for a URI (userinfo + host + port)
  53   * @property string $iauthority Authority part of the IRI (userinfo + host + port)
  54   * @property string $userinfo Userinfo part, formatted for a URI (after '://' and before '@')
  55   * @property string $iuserinfo Userinfo part of the IRI (after '://' and before '@')
  56   * @property string $host Host part, formatted for a URI
  57   * @property string $ihost Host part of the IRI
  58   * @property string $port Port part of the IRI (after ':')
  59   * @property string $path Path part, formatted for a URI (after first '/')
  60   * @property string $ipath Path part of the IRI (after first '/')
  61   * @property string $query Query part, formatted for a URI (after '?')
  62   * @property string $iquery Query part of the IRI (after '?')
  63   * @property string $fragment Fragment, formatted for a URI (after '#')
  64   * @property string $ifragment Fragment part of the IRI (after '#')
  65   */
  66  class Requests_IRI {
  67      /**
  68       * Scheme
  69       *
  70       * @var string|null
  71       */
  72      protected $scheme = null;
  73  
  74      /**
  75       * User Information
  76       *
  77       * @var string|null
  78       */
  79      protected $iuserinfo = null;
  80  
  81      /**
  82       * ihost
  83       *
  84       * @var string|null
  85       */
  86      protected $ihost = null;
  87  
  88      /**
  89       * Port
  90       *
  91       * @var string|null
  92       */
  93      protected $port = null;
  94  
  95      /**
  96       * ipath
  97       *
  98       * @var string
  99       */
 100      protected $ipath = '';
 101  
 102      /**
 103       * iquery
 104       *
 105       * @var string|null
 106       */
 107      protected $iquery = null;
 108  
 109      /**
 110       * ifragment|null
 111       *
 112       * @var string
 113       */
 114      protected $ifragment = null;
 115  
 116      /**
 117       * Normalization database
 118       *
 119       * Each key is the scheme, each value is an array with each key as the IRI
 120       * part and value as the default value for that part.
 121       *
 122       * @var array
 123       */
 124      protected $normalization = array(
 125          'acap' => array(
 126              'port' => 674
 127          ),
 128          'dict' => array(
 129              'port' => 2628
 130          ),
 131          'file' => array(
 132              'ihost' => 'localhost'
 133          ),
 134          'http' => array(
 135              'port' => 80,
 136          ),
 137          'https' => array(
 138              'port' => 443,
 139          ),
 140      );
 141  
 142      /**
 143       * Return the entire IRI when you try and read the object as a string
 144       *
 145       * @return string
 146       */
 147  	public function __toString() {
 148          return $this->get_iri();
 149      }
 150  
 151      /**
 152       * Overload __set() to provide access via properties
 153       *
 154       * @param string $name Property name
 155       * @param mixed $value Property value
 156       */
 157  	public function __set($name, $value) {
 158          if (method_exists($this, 'set_' . $name)) {
 159              call_user_func(array($this, 'set_' . $name), $value);
 160          }
 161          elseif (
 162                 $name === 'iauthority'
 163              || $name === 'iuserinfo'
 164              || $name === 'ihost'
 165              || $name === 'ipath'
 166              || $name === 'iquery'
 167              || $name === 'ifragment'
 168          ) {
 169              call_user_func(array($this, 'set_' . substr($name, 1)), $value);
 170          }
 171      }
 172  
 173      /**
 174       * Overload __get() to provide access via properties
 175       *
 176       * @param string $name Property name
 177       * @return mixed
 178       */
 179  	public function __get($name) {
 180          // isset() returns false for null, we don't want to do that
 181          // Also why we use array_key_exists below instead of isset()
 182          $props = get_object_vars($this);
 183  
 184          if (
 185              $name === 'iri' ||
 186              $name === 'uri' ||
 187              $name === 'iauthority' ||
 188              $name === 'authority'
 189          ) {
 190              $method = 'get_' . $name;
 191              $return = $this->$method();
 192          }
 193          elseif (array_key_exists($name, $props)) {
 194              $return = $this->$name;
 195          }
 196          // host -> ihost
 197          elseif (($prop = 'i' . $name) && array_key_exists($prop, $props)) {
 198              $name = $prop;
 199              $return = $this->$prop;
 200          }
 201          // ischeme -> scheme
 202          elseif (($prop = substr($name, 1)) && array_key_exists($prop, $props)) {
 203              $name = $prop;
 204              $return = $this->$prop;
 205          }
 206          else {
 207              trigger_error('Undefined property: ' . get_class($this) . '::' . $name, E_USER_NOTICE);
 208              $return = null;
 209          }
 210  
 211          if ($return === null && isset($this->normalization[$this->scheme][$name])) {
 212              return $this->normalization[$this->scheme][$name];
 213          }
 214          else {
 215              return $return;
 216          }
 217      }
 218  
 219      /**
 220       * Overload __isset() to provide access via properties
 221       *
 222       * @param string $name Property name
 223       * @return bool
 224       */
 225  	public function __isset($name) {
 226          return (method_exists($this, 'get_' . $name) || isset($this->$name));
 227      }
 228  
 229      /**
 230       * Overload __unset() to provide access via properties
 231       *
 232       * @param string $name Property name
 233       */
 234  	public function __unset($name) {
 235          if (method_exists($this, 'set_' . $name)) {
 236              call_user_func(array($this, 'set_' . $name), '');
 237          }
 238      }
 239  
 240      /**
 241       * Create a new IRI object, from a specified string
 242       *
 243       * @param string|null $iri
 244       */
 245  	public function __construct($iri = null) {
 246          $this->set_iri($iri);
 247      }
 248  
 249      /**
 250       * Create a new IRI object by resolving a relative IRI
 251       *
 252       * Returns false if $base is not absolute, otherwise an IRI.
 253       *
 254       * @param Requests_IRI|string $base (Absolute) Base IRI
 255       * @param Requests_IRI|string $relative Relative IRI
 256       * @return Requests_IRI|false
 257       */
 258  	public static function absolutize($base, $relative) {
 259          if (!($relative instanceof Requests_IRI)) {
 260              $relative = new Requests_IRI($relative);
 261          }
 262          if (!$relative->is_valid()) {
 263              return false;
 264          }
 265          elseif ($relative->scheme !== null) {
 266              return clone $relative;
 267          }
 268  
 269          if (!($base instanceof Requests_IRI)) {
 270              $base = new Requests_IRI($base);
 271          }
 272          if ($base->scheme === null || !$base->is_valid()) {
 273              return false;
 274          }
 275  
 276          if ($relative->get_iri() !== '') {
 277              if ($relative->iuserinfo !== null || $relative->ihost !== null || $relative->port !== null) {
 278                  $target = clone $relative;
 279                  $target->scheme = $base->scheme;
 280              }
 281              else {
 282                  $target = new Requests_IRI;
 283                  $target->scheme = $base->scheme;
 284                  $target->iuserinfo = $base->iuserinfo;
 285                  $target->ihost = $base->ihost;
 286                  $target->port = $base->port;
 287                  if ($relative->ipath !== '') {
 288                      if ($relative->ipath[0] === '/') {
 289                          $target->ipath = $relative->ipath;
 290                      }
 291                      elseif (($base->iuserinfo !== null || $base->ihost !== null || $base->port !== null) && $base->ipath === '') {
 292                          $target->ipath = '/' . $relative->ipath;
 293                      }
 294                      elseif (($last_segment = strrpos($base->ipath, '/')) !== false) {
 295                          $target->ipath = substr($base->ipath, 0, $last_segment + 1) . $relative->ipath;
 296                      }
 297                      else {
 298                          $target->ipath = $relative->ipath;
 299                      }
 300                      $target->ipath = $target->remove_dot_segments($target->ipath);
 301                      $target->iquery = $relative->iquery;
 302                  }
 303                  else {
 304                      $target->ipath = $base->ipath;
 305                      if ($relative->iquery !== null) {
 306                          $target->iquery = $relative->iquery;
 307                      }
 308                      elseif ($base->iquery !== null) {
 309                          $target->iquery = $base->iquery;
 310                      }
 311                  }
 312                  $target->ifragment = $relative->ifragment;
 313              }
 314          }
 315          else {
 316              $target = clone $base;
 317              $target->ifragment = null;
 318          }
 319          $target->scheme_normalization();
 320          return $target;
 321      }
 322  
 323      /**
 324       * Parse an IRI into scheme/authority/path/query/fragment segments
 325       *
 326       * @param string $iri
 327       * @return array
 328       */
 329  	protected function parse_iri($iri) {
 330          $iri = trim($iri, "\x20\x09\x0A\x0C\x0D");
 331          $has_match = preg_match('/^((?P<scheme>[^:\/?#]+):)?(\/\/(?P<authority>[^\/?#]*))?(?P<path>[^?#]*)(\?(?P<query>[^#]*))?(#(?P<fragment>.*))?$/', $iri, $match);
 332          if (!$has_match) {
 333              throw new Requests_Exception('Cannot parse supplied IRI', 'iri.cannot_parse', $iri);
 334          }
 335  
 336          if ($match[1] === '') {
 337              $match['scheme'] = null;
 338          }
 339          if (!isset($match[3]) || $match[3] === '') {
 340              $match['authority'] = null;
 341          }
 342          if (!isset($match[5])) {
 343              $match['path'] = '';
 344          }
 345          if (!isset($match[6]) || $match[6] === '') {
 346              $match['query'] = null;
 347          }
 348          if (!isset($match[8]) || $match[8] === '') {
 349              $match['fragment'] = null;
 350          }
 351          return $match;
 352      }
 353  
 354      /**
 355       * Remove dot segments from a path
 356       *
 357       * @param string $input
 358       * @return string
 359       */
 360  	protected function remove_dot_segments($input) {
 361          $output = '';
 362          while (strpos($input, './') !== false || strpos($input, '/.') !== false || $input === '.' || $input === '..') {
 363              // A: If the input buffer begins with a prefix of "../" or "./",
 364              // then remove that prefix from the input buffer; otherwise,
 365              if (strpos($input, '../') === 0) {
 366                  $input = substr($input, 3);
 367              }
 368              elseif (strpos($input, './') === 0) {
 369                  $input = substr($input, 2);
 370              }
 371              // B: if the input buffer begins with a prefix of "/./" or "/.",
 372              // where "." is a complete path segment, then replace that prefix
 373              // with "/" in the input buffer; otherwise,
 374              elseif (strpos($input, '/./') === 0) {
 375                  $input = substr($input, 2);
 376              }
 377              elseif ($input === '/.') {
 378                  $input = '/';
 379              }
 380              // C: if the input buffer begins with a prefix of "/../" or "/..",
 381              // where ".." is a complete path segment, then replace that prefix
 382              // with "/" in the input buffer and remove the last segment and its
 383              // preceding "/" (if any) from the output buffer; otherwise,
 384              elseif (strpos($input, '/../') === 0) {
 385                  $input = substr($input, 3);
 386                  $output = substr_replace($output, '', strrpos($output, '/'));
 387              }
 388              elseif ($input === '/..') {
 389                  $input = '/';
 390                  $output = substr_replace($output, '', strrpos($output, '/'));
 391              }
 392              // D: if the input buffer consists only of "." or "..", then remove
 393              // that from the input buffer; otherwise,
 394              elseif ($input === '.' || $input === '..') {
 395                  $input = '';
 396              }
 397              // E: move the first path segment in the input buffer to the end of
 398              // the output buffer, including the initial "/" character (if any)
 399              // and any subsequent characters up to, but not including, the next
 400              // "/" character or the end of the input buffer
 401              elseif (($pos = strpos($input, '/', 1)) !== false) {
 402                  $output .= substr($input, 0, $pos);
 403                  $input = substr_replace($input, '', 0, $pos);
 404              }
 405              else {
 406                  $output .= $input;
 407                  $input = '';
 408              }
 409          }
 410          return $output . $input;
 411      }
 412  
 413      /**
 414       * Replace invalid character with percent encoding
 415       *
 416       * @param string $string Input string
 417       * @param string $extra_chars Valid characters not in iunreserved or
 418       *                            iprivate (this is ASCII-only)
 419       * @param bool $iprivate Allow iprivate
 420       * @return string
 421       */
 422  	protected function replace_invalid_with_pct_encoding($string, $extra_chars, $iprivate = false) {
 423          // Normalize as many pct-encoded sections as possible
 424          $string = preg_replace_callback('/(?:%[A-Fa-f0-9]{2})+/', array($this, 'remove_iunreserved_percent_encoded'), $string);
 425  
 426          // Replace invalid percent characters
 427          $string = preg_replace('/%(?![A-Fa-f0-9]{2})/', '%25', $string);
 428  
 429          // Add unreserved and % to $extra_chars (the latter is safe because all
 430          // pct-encoded sections are now valid).
 431          $extra_chars .= 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-._~%';
 432  
 433          // Now replace any bytes that aren't allowed with their pct-encoded versions
 434          $position = 0;
 435          $strlen = strlen($string);
 436          while (($position += strspn($string, $extra_chars, $position)) < $strlen) {
 437              $value = ord($string[$position]);
 438  
 439              // Start position
 440              $start = $position;
 441  
 442              // By default we are valid
 443              $valid = true;
 444  
 445              // No one byte sequences are valid due to the while.
 446              // Two byte sequence:
 447              if (($value & 0xE0) === 0xC0) {
 448                  $character = ($value & 0x1F) << 6;
 449                  $length = 2;
 450                  $remaining = 1;
 451              }
 452              // Three byte sequence:
 453              elseif (($value & 0xF0) === 0xE0) {
 454                  $character = ($value & 0x0F) << 12;
 455                  $length = 3;
 456                  $remaining = 2;
 457              }
 458              // Four byte sequence:
 459              elseif (($value & 0xF8) === 0xF0) {
 460                  $character = ($value & 0x07) << 18;
 461                  $length = 4;
 462                  $remaining = 3;
 463              }
 464              // Invalid byte:
 465              else {
 466                  $valid = false;
 467                  $length = 1;
 468                  $remaining = 0;
 469              }
 470  
 471              if ($remaining) {
 472                  if ($position + $length <= $strlen) {
 473                      for ($position++; $remaining; $position++) {
 474                          $value = ord($string[$position]);
 475  
 476                          // Check that the byte is valid, then add it to the character:
 477                          if (($value & 0xC0) === 0x80) {
 478                              $character |= ($value & 0x3F) << (--$remaining * 6);
 479                          }
 480                          // If it is invalid, count the sequence as invalid and reprocess the current byte:
 481                          else {
 482                              $valid = false;
 483                              $position--;
 484                              break;
 485                          }
 486                      }
 487                  }
 488                  else {
 489                      $position = $strlen - 1;
 490                      $valid = false;
 491                  }
 492              }
 493  
 494              // Percent encode anything invalid or not in ucschar
 495              if (
 496                  // Invalid sequences
 497                  !$valid
 498                  // Non-shortest form sequences are invalid
 499                  || $length > 1 && $character <= 0x7F
 500                  || $length > 2 && $character <= 0x7FF
 501                  || $length > 3 && $character <= 0xFFFF
 502                  // Outside of range of ucschar codepoints
 503                  // Noncharacters
 504                  || ($character & 0xFFFE) === 0xFFFE
 505                  || $character >= 0xFDD0 && $character <= 0xFDEF
 506                  || (
 507                      // Everything else not in ucschar
 508                         $character > 0xD7FF && $character < 0xF900
 509                      || $character < 0xA0
 510                      || $character > 0xEFFFD
 511                  )
 512                  && (
 513                      // Everything not in iprivate, if it applies
 514                         !$iprivate
 515                      || $character < 0xE000
 516                      || $character > 0x10FFFD
 517                  )
 518              ) {
 519                  // If we were a character, pretend we weren't, but rather an error.
 520                  if ($valid) {
 521                      $position--;
 522                  }
 523  
 524                  for ($j = $start; $j <= $position; $j++) {
 525                      $string = substr_replace($string, sprintf('%%%02X', ord($string[$j])), $j, 1);
 526                      $j += 2;
 527                      $position += 2;
 528                      $strlen += 2;
 529                  }
 530              }
 531          }
 532  
 533          return $string;
 534      }
 535  
 536      /**
 537       * Callback function for preg_replace_callback.
 538       *
 539       * Removes sequences of percent encoded bytes that represent UTF-8
 540       * encoded characters in iunreserved
 541       *
 542       * @param array $match PCRE match
 543       * @return string Replacement
 544       */
 545  	protected function remove_iunreserved_percent_encoded($match) {
 546          // As we just have valid percent encoded sequences we can just explode
 547          // and ignore the first member of the returned array (an empty string).
 548          $bytes = explode('%', $match[0]);
 549  
 550          // Initialize the new string (this is what will be returned) and that
 551          // there are no bytes remaining in the current sequence (unsurprising
 552          // at the first byte!).
 553          $string = '';
 554          $remaining = 0;
 555  
 556          // Loop over each and every byte, and set $value to its value
 557          for ($i = 1, $len = count($bytes); $i < $len; $i++) {
 558              $value = hexdec($bytes[$i]);
 559  
 560              // If we're the first byte of sequence:
 561              if (!$remaining) {
 562                  // Start position
 563                  $start = $i;
 564  
 565                  // By default we are valid
 566                  $valid = true;
 567  
 568                  // One byte sequence:
 569                  if ($value <= 0x7F) {
 570                      $character = $value;
 571                      $length = 1;
 572                  }
 573                  // Two byte sequence:
 574                  elseif (($value & 0xE0) === 0xC0) {
 575                      $character = ($value & 0x1F) << 6;
 576                      $length = 2;
 577                      $remaining = 1;
 578                  }
 579                  // Three byte sequence:
 580                  elseif (($value & 0xF0) === 0xE0) {
 581                      $character = ($value & 0x0F) << 12;
 582                      $length = 3;
 583                      $remaining = 2;
 584                  }
 585                  // Four byte sequence:
 586                  elseif (($value & 0xF8) === 0xF0) {
 587                      $character = ($value & 0x07) << 18;
 588                      $length = 4;
 589                      $remaining = 3;
 590                  }
 591                  // Invalid byte:
 592                  else {
 593                      $valid = false;
 594                      $remaining = 0;
 595                  }
 596              }
 597              // Continuation byte:
 598              else {
 599                  // Check that the byte is valid, then add it to the character:
 600                  if (($value & 0xC0) === 0x80) {
 601                      $remaining--;
 602                      $character |= ($value & 0x3F) << ($remaining * 6);
 603                  }
 604                  // If it is invalid, count the sequence as invalid and reprocess the current byte as the start of a sequence:
 605                  else {
 606                      $valid = false;
 607                      $remaining = 0;
 608                      $i--;
 609                  }
 610              }
 611  
 612              // If we've reached the end of the current byte sequence, append it to Unicode::$data
 613              if (!$remaining) {
 614                  // Percent encode anything invalid or not in iunreserved
 615                  if (
 616                      // Invalid sequences
 617                      !$valid
 618                      // Non-shortest form sequences are invalid
 619                      || $length > 1 && $character <= 0x7F
 620                      || $length > 2 && $character <= 0x7FF
 621                      || $length > 3 && $character <= 0xFFFF
 622                      // Outside of range of iunreserved codepoints
 623                      || $character < 0x2D
 624                      || $character > 0xEFFFD
 625                      // Noncharacters
 626                      || ($character & 0xFFFE) === 0xFFFE
 627                      || $character >= 0xFDD0 && $character <= 0xFDEF
 628                      // Everything else not in iunreserved (this is all BMP)
 629                      || $character === 0x2F
 630                      || $character > 0x39 && $character < 0x41
 631                      || $character > 0x5A && $character < 0x61
 632                      || $character > 0x7A && $character < 0x7E
 633                      || $character > 0x7E && $character < 0xA0
 634                      || $character > 0xD7FF && $character < 0xF900
 635                  ) {
 636                      for ($j = $start; $j <= $i; $j++) {
 637                          $string .= '%' . strtoupper($bytes[$j]);
 638                      }
 639                  }
 640                  else {
 641                      for ($j = $start; $j <= $i; $j++) {
 642                          $string .= chr(hexdec($bytes[$j]));
 643                      }
 644                  }
 645              }
 646          }
 647  
 648          // If we have any bytes left over they are invalid (i.e., we are
 649          // mid-way through a multi-byte sequence)
 650          if ($remaining) {
 651              for ($j = $start; $j < $len; $j++) {
 652                  $string .= '%' . strtoupper($bytes[$j]);
 653              }
 654          }
 655  
 656          return $string;
 657      }
 658  
 659  	protected function scheme_normalization() {
 660          if (isset($this->normalization[$this->scheme]['iuserinfo']) && $this->iuserinfo === $this->normalization[$this->scheme]['iuserinfo']) {
 661              $this->iuserinfo = null;
 662          }
 663          if (isset($this->normalization[$this->scheme]['ihost']) && $this->ihost === $this->normalization[$this->scheme]['ihost']) {
 664              $this->ihost = null;
 665          }
 666          if (isset($this->normalization[$this->scheme]['port']) && $this->port === $this->normalization[$this->scheme]['port']) {
 667              $this->port = null;
 668          }
 669          if (isset($this->normalization[$this->scheme]['ipath']) && $this->ipath === $this->normalization[$this->scheme]['ipath']) {
 670              $this->ipath = '';
 671          }
 672          if (isset($this->ihost) && empty($this->ipath)) {
 673              $this->ipath = '/';
 674          }
 675          if (isset($this->normalization[$this->scheme]['iquery']) && $this->iquery === $this->normalization[$this->scheme]['iquery']) {
 676              $this->iquery = null;
 677          }
 678          if (isset($this->normalization[$this->scheme]['ifragment']) && $this->ifragment === $this->normalization[$this->scheme]['ifragment']) {
 679              $this->ifragment = null;
 680          }
 681      }
 682  
 683      /**
 684       * Check if the object represents a valid IRI. This needs to be done on each
 685       * call as some things change depending on another part of the IRI.
 686       *
 687       * @return bool
 688       */
 689  	public function is_valid() {
 690          $isauthority = $this->iuserinfo !== null || $this->ihost !== null || $this->port !== null;
 691          if ($this->ipath !== '' &&
 692              (
 693                  $isauthority && $this->ipath[0] !== '/' ||
 694                  (
 695                      $this->scheme === null &&
 696                      !$isauthority &&
 697                      strpos($this->ipath, ':') !== false &&
 698                      (strpos($this->ipath, '/') === false ? true : strpos($this->ipath, ':') < strpos($this->ipath, '/'))
 699                  )
 700              )
 701          ) {
 702              return false;
 703          }
 704  
 705          return true;
 706      }
 707  
 708      /**
 709       * Set the entire IRI. Returns true on success, false on failure (if there
 710       * are any invalid characters).
 711       *
 712       * @param string $iri
 713       * @return bool
 714       */
 715  	protected function set_iri($iri) {
 716          static $cache;
 717          if (!$cache) {
 718              $cache = array();
 719          }
 720  
 721          if ($iri === null) {
 722              return true;
 723          }
 724          if (isset($cache[$iri])) {
 725              list($this->scheme,
 726                   $this->iuserinfo,
 727                   $this->ihost,
 728                   $this->port,
 729                   $this->ipath,
 730                   $this->iquery,
 731                   $this->ifragment,
 732                   $return) = $cache[$iri];
 733              return $return;
 734          }
 735  
 736          $parsed = $this->parse_iri((string) $iri);
 737  
 738          $return = $this->set_scheme($parsed['scheme'])
 739              && $this->set_authority($parsed['authority'])
 740              && $this->set_path($parsed['path'])
 741              && $this->set_query($parsed['query'])
 742              && $this->set_fragment($parsed['fragment']);
 743  
 744          $cache[$iri] = array($this->scheme,
 745                               $this->iuserinfo,
 746                               $this->ihost,
 747                               $this->port,
 748                               $this->ipath,
 749                               $this->iquery,
 750                               $this->ifragment,
 751                               $return);
 752          return $return;
 753      }
 754  
 755      /**
 756       * Set the scheme. Returns true on success, false on failure (if there are
 757       * any invalid characters).
 758       *
 759       * @param string $scheme
 760       * @return bool
 761       */
 762  	protected function set_scheme($scheme) {
 763          if ($scheme === null) {
 764              $this->scheme = null;
 765          }
 766          elseif (!preg_match('/^[A-Za-z][0-9A-Za-z+\-.]*$/', $scheme)) {
 767              $this->scheme = null;
 768              return false;
 769          }
 770          else {
 771              $this->scheme = strtolower($scheme);
 772          }
 773          return true;
 774      }
 775  
 776      /**
 777       * Set the authority. Returns true on success, false on failure (if there are
 778       * any invalid characters).
 779       *
 780       * @param string $authority
 781       * @return bool
 782       */
 783  	protected function set_authority($authority) {
 784          static $cache;
 785          if (!$cache) {
 786              $cache = array();
 787          }
 788  
 789          if ($authority === null) {
 790              $this->iuserinfo = null;
 791              $this->ihost = null;
 792              $this->port = null;
 793              return true;
 794          }
 795          if (isset($cache[$authority])) {
 796              list($this->iuserinfo,
 797                   $this->ihost,
 798                   $this->port,
 799                   $return) = $cache[$authority];
 800  
 801              return $return;
 802          }
 803  
 804          $remaining = $authority;
 805          if (($iuserinfo_end = strrpos($remaining, '@')) !== false) {
 806              $iuserinfo = substr($remaining, 0, $iuserinfo_end);
 807              $remaining = substr($remaining, $iuserinfo_end + 1);
 808          }
 809          else {
 810              $iuserinfo = null;
 811          }
 812          if (($port_start = strpos($remaining, ':', strpos($remaining, ']'))) !== false) {
 813              $port = substr($remaining, $port_start + 1);
 814              if ($port === false || $port === '') {
 815                  $port = null;
 816              }
 817              $remaining = substr($remaining, 0, $port_start);
 818          }
 819          else {
 820              $port = null;
 821          }
 822  
 823          $return = $this->set_userinfo($iuserinfo) &&
 824                    $this->set_host($remaining) &&
 825                    $this->set_port($port);
 826  
 827          $cache[$authority] = array($this->iuserinfo,
 828                                     $this->ihost,
 829                                     $this->port,
 830                                     $return);
 831  
 832          return $return;
 833      }
 834  
 835      /**
 836       * Set the iuserinfo.
 837       *
 838       * @param string $iuserinfo
 839       * @return bool
 840       */
 841  	protected function set_userinfo($iuserinfo) {
 842          if ($iuserinfo === null) {
 843              $this->iuserinfo = null;
 844          }
 845          else {
 846              $this->iuserinfo = $this->replace_invalid_with_pct_encoding($iuserinfo, '!$&\'()*+,;=:');
 847              $this->scheme_normalization();
 848          }
 849  
 850          return true;
 851      }
 852  
 853      /**
 854       * Set the ihost. Returns true on success, false on failure (if there are
 855       * any invalid characters).
 856       *
 857       * @param string $ihost
 858       * @return bool
 859       */
 860  	protected function set_host($ihost) {
 861          if ($ihost === null) {
 862              $this->ihost = null;
 863              return true;
 864          }
 865          if (substr($ihost, 0, 1) === '[' && substr($ihost, -1) === ']') {
 866              if (Requests_IPv6::check_ipv6(substr($ihost, 1, -1))) {
 867                  $this->ihost = '[' . Requests_IPv6::compress(substr($ihost, 1, -1)) . ']';
 868              }
 869              else {
 870                  $this->ihost = null;
 871                  return false;
 872              }
 873          }
 874          else {
 875              $ihost = $this->replace_invalid_with_pct_encoding($ihost, '!$&\'()*+,;=');
 876  
 877              // Lowercase, but ignore pct-encoded sections (as they should
 878              // remain uppercase). This must be done after the previous step
 879              // as that can add unescaped characters.
 880              $position = 0;
 881              $strlen = strlen($ihost);
 882              while (($position += strcspn($ihost, 'ABCDEFGHIJKLMNOPQRSTUVWXYZ%', $position)) < $strlen) {
 883                  if ($ihost[$position] === '%') {
 884                      $position += 3;
 885                  }
 886                  else {
 887                      $ihost[$position] = strtolower($ihost[$position]);
 888                      $position++;
 889                  }
 890              }
 891  
 892              $this->ihost = $ihost;
 893          }
 894  
 895          $this->scheme_normalization();
 896  
 897          return true;
 898      }
 899  
 900      /**
 901       * Set the port. Returns true on success, false on failure (if there are
 902       * any invalid characters).
 903       *
 904       * @param string $port
 905       * @return bool
 906       */
 907  	protected function set_port($port) {
 908          if ($port === null) {
 909              $this->port = null;
 910              return true;
 911          }
 912  
 913          if (strspn($port, '0123456789') === strlen($port)) {
 914              $this->port = (int) $port;
 915              $this->scheme_normalization();
 916              return true;
 917          }
 918  
 919          $this->port = null;
 920          return false;
 921      }
 922  
 923      /**
 924       * Set the ipath.
 925       *
 926       * @param string $ipath
 927       * @return bool
 928       */
 929  	protected function set_path($ipath) {
 930          static $cache;
 931          if (!$cache) {
 932              $cache = array();
 933          }
 934  
 935          $ipath = (string) $ipath;
 936  
 937          if (isset($cache[$ipath])) {
 938              $this->ipath = $cache[$ipath][(int) ($this->scheme !== null)];
 939          }
 940          else {
 941              $valid = $this->replace_invalid_with_pct_encoding($ipath, '!$&\'()*+,;=@:/');
 942              $removed = $this->remove_dot_segments($valid);
 943  
 944              $cache[$ipath] = array($valid, $removed);
 945              $this->ipath = ($this->scheme !== null) ? $removed : $valid;
 946          }
 947          $this->scheme_normalization();
 948          return true;
 949      }
 950  
 951      /**
 952       * Set the iquery.
 953       *
 954       * @param string $iquery
 955       * @return bool
 956       */
 957  	protected function set_query($iquery) {
 958          if ($iquery === null) {
 959              $this->iquery = null;
 960          }
 961          else {
 962              $this->iquery = $this->replace_invalid_with_pct_encoding($iquery, '!$&\'()*+,;=:@/?', true);
 963              $this->scheme_normalization();
 964          }
 965          return true;
 966      }
 967  
 968      /**
 969       * Set the ifragment.
 970       *
 971       * @param string $ifragment
 972       * @return bool
 973       */
 974  	protected function set_fragment($ifragment) {
 975          if ($ifragment === null) {
 976              $this->ifragment = null;
 977          }
 978          else {
 979              $this->ifragment = $this->replace_invalid_with_pct_encoding($ifragment, '!$&\'()*+,;=:@/?');
 980              $this->scheme_normalization();
 981          }
 982          return true;
 983      }
 984  
 985      /**
 986       * Convert an IRI to a URI (or parts thereof)
 987       *
 988       * @param string|bool IRI to convert (or false from {@see get_iri})
 989       * @return string|false URI if IRI is valid, false otherwise.
 990       */
 991  	protected function to_uri($string) {
 992          if (!is_string($string)) {
 993              return false;
 994          }
 995  
 996          static $non_ascii;
 997          if (!$non_ascii) {
 998              $non_ascii = implode('', range("\x80", "\xFF"));
 999          }
1000  
1001          $position = 0;
1002          $strlen = strlen($string);
1003          while (($position += strcspn($string, $non_ascii, $position)) < $strlen) {
1004              $string = substr_replace($string, sprintf('%%%02X', ord($string[$position])), $position, 1);
1005              $position += 3;
1006              $strlen += 2;
1007          }
1008  
1009          return $string;
1010      }
1011  
1012      /**
1013       * Get the complete IRI
1014       *
1015       * @return string|false
1016       */
1017  	protected function get_iri() {
1018          if (!$this->is_valid()) {
1019              return false;
1020          }
1021  
1022          $iri = '';
1023          if ($this->scheme !== null) {
1024              $iri .= $this->scheme . ':';
1025          }
1026          if (($iauthority = $this->get_iauthority()) !== null) {
1027              $iri .= '//' . $iauthority;
1028          }
1029          $iri .= $this->ipath;
1030          if ($this->iquery !== null) {
1031              $iri .= '?' . $this->iquery;
1032          }
1033          if ($this->ifragment !== null) {
1034              $iri .= '#' . $this->ifragment;
1035          }
1036  
1037          return $iri;
1038      }
1039  
1040      /**
1041       * Get the complete URI
1042       *
1043       * @return string
1044       */
1045  	protected function get_uri() {
1046          return $this->to_uri($this->get_iri());
1047      }
1048  
1049      /**
1050       * Get the complete iauthority
1051       *
1052       * @return string|null
1053       */
1054  	protected function get_iauthority() {
1055          if ($this->iuserinfo === null && $this->ihost === null && $this->port === null) {
1056              return null;
1057          }
1058  
1059          $iauthority = '';
1060          if ($this->iuserinfo !== null) {
1061              $iauthority .= $this->iuserinfo . '@';
1062          }
1063          if ($this->ihost !== null) {
1064              $iauthority .= $this->ihost;
1065          }
1066          if ($this->port !== null) {
1067              $iauthority .= ':' . $this->port;
1068          }
1069          return $iauthority;
1070      }
1071  
1072      /**
1073       * Get the complete authority
1074       *
1075       * @return string
1076       */
1077  	protected function get_authority() {
1078          $iauthority = $this->get_iauthority();
1079          if (is_string($iauthority)) {
1080              return $this->to_uri($iauthority);
1081          }
1082          else {
1083              return $iauthority;
1084          }
1085      }
1086  }