mcs/class/corlib/Mono.Security/Uri.cs

   1 //
   2 // Mono.Security.Uri
   3 //      Adapted from System.Uri (in System.dll assembly) for its use in corlib
   4 //
   5 // Authors:
   6 //    Lawrence Pit (loz@cable.a2000.nl)
   7 //    Garrett Rooney (rooneg@electricjellyfish.net)
   8 //    Ian MacLean (ianm@activestate.com)
   9 //    Ben Maurer (bmaurer@users.sourceforge.net)
  10 //    Atsushi Enomoto (atsushi@ximian.com)
  11 //    Stephane Delcroix  <stephane@delcroix.org>
  12 //
  13 // (C) 2001 Garrett Rooney
  14 // (C) 2003 Ian MacLean
  15 // (C) 2003 Ben Maurer
  16 // (C) 2003 Novell inc.
  17 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
  18 //
  19 // Permission is hereby granted, free of charge, to any person obtaining
  20 // a copy of this software and associated documentation files (the
  21 // "Software"), to deal in the Software without restriction, including
  22 // without limitation the rights to use, copy, modify, merge, publish,
  23 // distribute, sublicense, and/or sell copies of the Software, and to
  24 // permit persons to whom the Software is furnished to do so, subject to
  25 // the following conditions:
  26 //
  27 // The above copyright notice and this permission notice shall be
  28 // included in all copies or substantial portions of the Software.
  29 //
  30 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  31 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  32 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  33 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  34 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  35 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  36 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  37 //
  38
  39 using System;
  40 using System.IO;
  41 using System.Text;
  42 using System.Collections;
  43 using System.Globalization;
  44
  45 // See RFC 2396 for more info on URI's.
  46
  47 // TODO: optimize by parsing host string only once
  48
  49 namespace Mono.Security {
  50
  51 #if INSIDE_CORLIB
  52         internal
  53 #else
  54         public
  55 #endif
  56         enum UriPartial {
  57                 Scheme = 0,
  58                 Authority = 1,
  59                 Path = 2,
  60         }
  61
  62 #if INSIDE_CORLIB
  63         internal
  64 #else
  65         public
  66 #endif
  67         class Uri {
  68
  69                 // NOTES:
  70                 // o  scheme excludes the scheme delimiter
  71                 // o  port is -1 to indicate no port is defined
  72                 // o  path is empty or starts with / when scheme delimiter == "://"
  73                 // o  query is empty or starts with ? char, escaped.
  74                 // o  fragment is empty or starts with # char, unescaped.
  75                 // o  all class variables are in escaped format when they are escapable,
  76                 //    except cachedToString.
  77                 // o  UNC is supported, as starts with "\\" for windows,
  78                 //    or "//" with unix.
  79
  80                 private bool isUnixFilePath = false;
  81                 private string source;
  82                 private string scheme = String.Empty;
  83                 private string host = String.Empty;
  84                 private int port = -1;
  85                 private string path = String.Empty;
  86                 private string query = String.Empty;
  87                 private string fragment = String.Empty;
  88                 private string userinfo = String.Empty;
  89                 private bool isUnc = false;
  90                 private bool isOpaquePart = false;
  91
  92                 private string [] segments;
  93
  94                 private bool userEscaped = false;
  95                 private string cachedAbsoluteUri = null;
  96                 private string cachedToString = null;
  97                 private string cachedLocalPath = null;
  98                 private int cachedHashCode = 0;
  99                 private bool reduce = true;
 100
 101                 private static readonly string hexUpperChars = "0123456789ABCDEF";
 102
 103                 // Fields
 104
 105                 public static readonly string SchemeDelimiter = "://";
 106                 public static readonly string UriSchemeFile = "file";
 107                 public static readonly string UriSchemeFtp = "ftp";
 108                 public static readonly string UriSchemeGopher = "gopher";
 109                 public static readonly string UriSchemeHttp = "http";
 110                 public static readonly string UriSchemeHttps = "https";
 111                 public static readonly string UriSchemeMailto = "mailto";
 112                 public static readonly string UriSchemeNews = "news";
 113                 public static readonly string UriSchemeNntp = "nntp";
 114
 115                 // Constructors
 116
 117                 public Uri (string uriString) : this (uriString, false)
 118                 {
 119                 }
 120
 121                 public Uri (string uriString, bool dontEscape)
 122                 {
 123                         userEscaped = dontEscape;
 124                         source = uriString;
 125                         Parse ();
 126                 }
 127
 128                 public Uri (string uriString, bool dontEscape, bool reduce)
 129                 {
 130                         userEscaped = dontEscape;
 131                         source = uriString;
 132                         this.reduce = reduce;
 133                         Parse ();
 134                 }
 135
 136                 public Uri (Uri baseUri, string relativeUri)
 137                         : this (baseUri, relativeUri, false)
 138                 {
 139                 }
 140
 141                 public Uri (Uri baseUri, string relativeUri, bool dontEscape)
 142                 {
 143                         if (baseUri == null)
 144                                 throw new NullReferenceException ("baseUri");
 145
 146                         // See RFC 2396 Par 5.2 and Appendix C
 147
 148                         userEscaped = dontEscape;
 149
 150                         if (relativeUri == null)
 151                                 throw new NullReferenceException ("relativeUri");
 152
 153                         // Check Windows UNC (for // it is scheme/host separator)
 154                         if (relativeUri.StartsWith ("\\\\")) {
 155                                 source = relativeUri;
 156                                 Parse ();
 157                                 return;
 158                         }
 159
 160                         int pos = relativeUri.IndexOf (':');
 161                         if (pos != -1) {
 162
 163                                 int pos2 = relativeUri.IndexOfAny (new char [] {'/', '\\', '?'});
 164
 165                                 // pos2 < 0 ... e.g. mailto
 166                                 // pos2 > pos ... to block ':' in query part
 167                                 if (pos2 > pos || pos2 < 0) {
 168                                         // equivalent to new Uri (relativeUri, dontEscape)
 169                                         source = relativeUri;
 170                                         Parse ();
 171
 172                                         return;
 173                                 }
 174                         }
 175
 176                         this.scheme = baseUri.scheme;
 177                         this.host = baseUri.host;
 178                         this.port = baseUri.port;
 179                         this.userinfo = baseUri.userinfo;
 180                         this.isUnc = baseUri.isUnc;
 181                         this.isUnixFilePath = baseUri.isUnixFilePath;
 182                         this.isOpaquePart = baseUri.isOpaquePart;
 183
 184                         if (relativeUri == String.Empty) {
 185                                 this.path = baseUri.path;
 186                                 this.query = baseUri.query;
 187                                 this.fragment = baseUri.fragment;
 188                                 return;
 189                         }
 190
 191                         // 8 fragment
 192                         // Note that in relative constructor, file URI cannot handle '#' as a filename character, but just regarded as a fragment identifier.
 193                         pos = relativeUri.IndexOf ('#');
 194                         if (pos != -1) {
 195                                 fragment = relativeUri.Substring (pos);
 196                                 // fragment is not escaped.
 197                                 relativeUri = relativeUri.Substring (0, pos);
 198                         }
 199
 200                         // 6 query
 201                         pos = relativeUri.IndexOf ('?');
 202                         if (pos != -1) {
 203                                 query = relativeUri.Substring (pos);
 204                                 if (!userEscaped)
 205                                         query = EscapeString (query);
 206                                 relativeUri = relativeUri.Substring (0, pos);
 207                         }
 208
 209                         if (relativeUri.Length > 0 && relativeUri [0] == '/') {
 210                                 if (relativeUri.Length > 1 && relativeUri [1] == '/') {
 211                                         source = scheme + ':' + relativeUri;
 212                                         Parse ();
 213                                         return;
 214                                 } else {
 215                                         path = relativeUri;
 216                                         if (!userEscaped)
 217                                                 path = EscapeString (path);
 218                                         return;
 219                                 }
 220                         }
 221
 222                         // par 5.2 step 6 a)
 223                         path = baseUri.path;
 224                         if (relativeUri.Length > 0 || query.Length > 0) {
 225                                 pos = path.LastIndexOf ('/');
 226                                 if (pos >= 0)
 227                                         path = path.Substring (0, pos + 1);
 228                         }
 229
 230                         if(relativeUri.Length == 0)
 231                                 return;
 232
 233                         // 6 b)
 234                         path += relativeUri;
 235
 236                         // 6 c)
 237                         int startIndex = 0;
 238                         while (true) {
 239                                 pos = path.IndexOf ("./", startIndex);
 240                                 if (pos == -1)
 241                                         break;
 242                                 if (pos == 0)
 243                                         path = path.Remove (0, 2);
 244                                 else if (path [pos - 1] != '.')
 245                                         path = path.Remove (pos, 2);
 246                                 else
 247                                         startIndex = pos + 1;
 248                         }
 249
 250                         // 6 d)
 251                         if (path.Length > 1 &&
 252                             path [path.Length - 1] == '.' &&
 253                             path [path.Length - 2] == '/')
 254                                 path = path.Remove (path.Length - 1, 1);
 255
 256                         // 6 e)
 257                         startIndex = 0;
 258                         while (true) {
 259                                 pos = path.IndexOf ("/../", startIndex);
 260                                 if (pos == -1)
 261                                         break;
 262                                 if (pos == 0) {
 263                                         startIndex = 3;
 264                                         continue;
 265                                 }
 266                                 int pos2 = path.LastIndexOf ('/', pos - 1);
 267                                 if (pos2 == -1) {
 268                                         startIndex = pos + 1;
 269                                 } else {
 270                                         if (path.Substring (pos2 + 1, pos - pos2 - 1) != "..")
 271                                                 path = path.Remove (pos2 + 1, pos - pos2 + 3);
 272                                         else
 273                                                 startIndex = pos + 1;
 274                                 }
 275                         }
 276
 277                         // 6 f)
 278                         if (path.Length > 3 && path.EndsWith ("/..")) {
 279                                 pos = path.LastIndexOf ('/', path.Length - 4);
 280                                 if (pos != -1)
 281                                         if (path.Substring (pos + 1, path.Length - pos - 4) != "..")
 282                                                 path = path.Remove (pos + 1, path.Length - pos - 1);
 283                         }
 284
 285                         if (!userEscaped)
 286                                 path = EscapeString (path);
 287                 }
 288
 289                 // Properties
 290
 291                 public string AbsolutePath {
 292                         get { return path; }
 293                 }
 294
 295                 public string AbsoluteUri {
 296                         get {
 297                                 if (cachedAbsoluteUri == null) {
 298                                         cachedAbsoluteUri = GetLeftPart (UriPartial.Path) + query + fragment;
 299                                 }
 300                                 return cachedAbsoluteUri;
 301                         }
 302                 }
 303
 304                 public string Authority {
 305                         get {
 306                                 return (GetDefaultPort (scheme) == port)
 307                                      ? host : host + ":" + port;
 308                         }
 309                 }
 310
 311                 public string Fragment {
 312                         get { return fragment; }
 313                 }
 314
 315                 public string Host {
 316                         get { return host; }
 317                 }
 318
 319 /*              public UriHostNameType HostNameType {
 320                         get {
 321                                 UriHostNameType ret = CheckHostName (host);
 322                                 if (ret != UriHostNameType.Unknown)
 323                                         return ret;
 324
 325                                 // looks it always returns Basic...
 326                                 return UriHostNameType.Basic; //.Unknown;
 327                         }
 328                 }*/
 329
 330                 public bool IsDefaultPort {
 331                         get { return GetDefaultPort (scheme) == port; }
 332                 }
 333
 334                 public bool IsFile {
 335                         get { return (scheme == UriSchemeFile); }
 336                 }
 337
 338                 public bool IsLoopback {
 339                         get {
 340                                 if (host == String.Empty)
 341                                         return false;
 342
 343                                 if (host == "loopback" || host == "localhost")
 344                                         return true;
 345 /*
 346                                 try {
 347                                         if (IPAddress.Loopback.Equals (IPAddress.Parse (host)))
 348                                                 return true;
 349                                 } catch (FormatException) {}
 350
 351                                 try {
 352                                         return IPv6Address.IsLoopback (IPv6Address.Parse (host));
 353                                 } catch (FormatException) {}
 354 */
 355                                 return false;
 356                         }
 357                 }
 358
 359                 public bool IsUnc {
 360                         // rule: This should be true only if
 361                         //   - uri string starts from "\\", or
 362                         //   - uri string starts from "//" (Samba way)
 363                         get { return isUnc; }
 364                 }
 365
 366                 public string LocalPath {
 367                         get {
 368                                 if (cachedLocalPath != null)
 369                                         return cachedLocalPath;
 370                                 if (!IsFile)
 371                                         return AbsolutePath;
 372
 373                                 bool windows = (path.Length > 3 && path [1] == ':' &&
 374                                                 (path [2] == '\\' || path [2] == '/'));
 375
 376                                 if (!IsUnc) {
 377                                         string p = Unescape (path);
 378                                         if (System.IO.Path.DirectorySeparatorChar == '\\' || windows)
 379                                                 cachedLocalPath = p.Replace ('/', '\\');
 380                                         else
 381                                                 cachedLocalPath = p;
 382                                 } else {
 383                                         // support *nix and W32 styles
 384                                         if (path.Length > 1 && path [1] == ':')
 385                                                 cachedLocalPath = Unescape (path.Replace (Path.AltDirectorySeparatorChar, Path.DirectorySeparatorChar));
 386
 387                                         // LAMESPEC: ok, now we cannot determine
 388                                         // if such URI like "file://foo/bar" is
 389                                         // Windows UNC or unix file path, so
 390                                         // they should be handled differently.
 391                                         else if (System.IO.Path.DirectorySeparatorChar == '\\')
 392                                                 cachedLocalPath = "\\\\" + Unescape (host + path.Replace ('/', '\\'));
 393                                         else
 394                                                 cachedLocalPath = Unescape (path);
 395                                 }
 396                                 if (cachedLocalPath == String.Empty)
 397                                         cachedLocalPath = Path.DirectorySeparatorChar.ToString ();
 398                                 return cachedLocalPath;
 399                         }
 400                 }
 401
 402                 public string PathAndQuery {
 403                         get { return path + query; }
 404                 }
 405
 406                 public int Port {
 407                         get { return port; }
 408                 }
 409
 410                 public string Query {
 411                         get { return query; }
 412                 }
 413
 414                 public string Scheme {
 415                         get { return scheme; }
 416                 }
 417
 418                 public string [] Segments {
 419                         get {
 420                                 if (segments != null)
 421                                         return segments;
 422
 423                                 if (path.Length == 0) {
 424                                         segments = new string [0];
 425                                         return segments;
 426                                 }
 427
 428                                 string [] parts = path.Split ('/');
 429                                 segments = parts;
 430                                 bool endSlash = path.EndsWith ("/");
 431                                 if (parts.Length > 0 && endSlash) {
 432                                         string [] newParts = new string [parts.Length - 1];
 433                                         Array.Copy (parts, 0, newParts, 0, parts.Length - 1);
 434                                         parts = newParts;
 435                                 }
 436
 437                                 int i = 0;
 438                                 if (IsFile && path.Length > 1 && path [1] == ':') {
 439                                         string [] newParts = new string [parts.Length + 1];
 440                                         Array.Copy (parts, 1, newParts, 2, parts.Length - 1);
 441                                         parts = newParts;
 442                                         parts [0] = path.Substring (0, 2);
 443                                         parts [1] = String.Empty;
 444                                         i++;
 445                                 }
 446
 447                                 int end = parts.Length;
 448                                 for (; i < end; i++)
 449                                         if (i != end - 1 || endSlash)
 450                                                 parts [i] += '/';
 451
 452                                 segments = parts;
 453                                 return segments;
 454                         }
 455                 }
 456
 457                 public bool UserEscaped {
 458                         get { return userEscaped; }
 459                 }
 460
 461                 public string UserInfo {
 462                         get { return userinfo; }
 463                 }
 464
 465
 466                 // Methods
 467
 468 /*              public static UriHostNameType CheckHostName (string name)
 469                 {
 470                         if (name == null || name.Length == 0)
 471                                 return UriHostNameType.Unknown;
 472
 473                         if (IsIPv4Address (name))
 474                                 return UriHostNameType.IPv4;
 475
 476                         if (IsDomainAddress (name))
 477                                 return UriHostNameType.Dns;
 478
 479                         try {
 480                                 IPv6Address.Parse (name);
 481                                 return UriHostNameType.IPv6;
 482                         } catch (FormatException) {}
 483
 484                         return UriHostNameType.Unknown;
 485                 }*/
 486
 487                 internal static bool IsIPv4Address (string name)
 488                 {
 489                         string [] captures = name.Split (new char [] {'.'});
 490                         if (captures.Length != 4)
 491                                 return false;
 492                         for (int i = 0; i < 4; i++) {
 493                                 try {
 494                                         int d = Int32.Parse (captures [i], CultureInfo.InvariantCulture);
 495                                         if (d < 0 || d > 255)
 496                                                 return false;
 497                                 } catch (Exception) {
 498                                         return false;
 499                                 }
 500                         }
 501                         return true;
 502                 }
 503
 504                 internal static bool IsDomainAddress (string name)
 505                 {
 506                         int len = name.Length;
 507
 508                         if (name [len - 1] == '.')
 509                                 return false;
 510
 511                         int count = 0;
 512                         for (int i = 0; i < len; i++) {
 513                                 char c = name [i];
 514                                 if (count == 0) {
 515                                         if (!Char.IsLetterOrDigit (c))
 516                                                 return false;
 517                                 } else if (c == '.') {
 518                                         count = 0;
 519                                 } else if (!Char.IsLetterOrDigit (c) && c != '-' && c != '_') {
 520                                         return false;
 521                                 }
 522                                 if (++count == 64)
 523                                         return false;
 524                         }
 525
 526                         return true;
 527                 }
 528
 529                 public static bool CheckSchemeName (string schemeName)
 530                 {
 531                         if (schemeName == null || schemeName.Length == 0)
 532                                 return false;
 533
 534                         if (!Char.IsLetter (schemeName [0]))
 535                                 return false;
 536
 537                         int len = schemeName.Length;
 538                         for (int i = 1; i < len; i++) {
 539                                 char c = schemeName [i];
 540                                 if (!Char.IsLetterOrDigit (c) && c != '.' && c != '+' && c != '-')
 541                                         return false;
 542                         }
 543
 544                         return true;
 545                 }
 546
 547                 public override bool Equals (object comparant)
 548                 {
 549                         if (comparant == null)
 550                                 return false;
 551
 552                         Uri uri = comparant as Uri;
 553                         if (uri == null) {
 554                                 string s = comparant as String;
 555                                 if (s == null)
 556                                         return false;
 557                                 uri = new Uri (s);
 558                         }
 559
 560                         CultureInfo inv = CultureInfo.InvariantCulture;
 561                         return ((this.scheme.ToLower (inv) == uri.scheme.ToLower (inv)) &&
 562                                 (this.userinfo.ToLower (inv) == uri.userinfo.ToLower (inv)) &&
 563                                 (this.host.ToLower (inv) == uri.host.ToLower (inv)) &&
 564                                 (this.port == uri.port) &&
 565                                 (this.path == uri.path) &&
 566                                 (this.query.ToLower (inv) == uri.query.ToLower (inv)));
 567                 }
 568
 569                 public override int GetHashCode ()
 570                 {
 571                         if (cachedHashCode == 0)
 572                                 cachedHashCode = scheme.GetHashCode ()
 573                                                + userinfo.GetHashCode ()
 574                                                + host.GetHashCode ()
 575                                                + port
 576                                                + path.GetHashCode ()
 577                                                + query.GetHashCode ();
 578                         return cachedHashCode;
 579                 }
 580
 581                 public string GetLeftPart (UriPartial part)
 582                 {
 583                         int defaultPort;
 584                         switch (part) {
 585                         case UriPartial.Scheme :
 586                                 return scheme + GetOpaqueWiseSchemeDelimiter ();
 587                         case UriPartial.Authority :
 588                                 if (host == String.Empty ||
 589                                     scheme == Uri.UriSchemeMailto ||
 590                                     scheme == Uri.UriSchemeNews)
 591                                         return String.Empty;
 592
 593                                 StringBuilder s = new StringBuilder ();
 594                                 s.Append (scheme);
 595                                 s.Append (GetOpaqueWiseSchemeDelimiter ());
 596                                 if (path.Length > 1 && path [1] == ':' && (Uri.UriSchemeFile == scheme))
 597                                         s.Append ('/');  // win32 file
 598                                 if (userinfo.Length > 0)
 599                                         s.Append (userinfo).Append ('@');
 600                                 s.Append (host);
 601                                 defaultPort = GetDefaultPort (scheme);
 602                                 if ((port != -1) && (port != defaultPort))
 603                                         s.Append (':').Append (port);
 604                                 return s.ToString ();
 605                         case UriPartial.Path :
 606                                 StringBuilder sb = new StringBuilder ();
 607                                 sb.Append (scheme);
 608                                 sb.Append (GetOpaqueWiseSchemeDelimiter ());
 609                                 if (path.Length > 1 && path [1] == ':' && (Uri.UriSchemeFile == scheme))
 610                                         sb.Append ('/');  // win32 file
 611                                 if (userinfo.Length > 0)
 612                                         sb.Append (userinfo).Append ('@');
 613                                 sb.Append (host);
 614                                 defaultPort = GetDefaultPort (scheme);
 615                                 if ((port != -1) && (port != defaultPort))
 616                                         sb.Append (':').Append (port);
 617                                 sb.Append (path);
 618                                 return sb.ToString ();
 619                         }
 620                         return null;
 621                 }
 622
 623                 public static int FromHex (char digit)
 624                 {
 625                         if ('0' <= digit && digit <= '9') {
 626                                 return (int) (digit - '0');
 627                         }
 628
 629                         if ('a' <= digit && digit <= 'f')
 630                                 return (int) (digit - 'a' + 10);
 631
 632                         if ('A' <= digit && digit <= 'F')
 633                                 return (int) (digit - 'A' + 10);
 634
 635                         throw new ArgumentException ("digit");
 636                 }
 637
 638                 public static string HexEscape (char character)
 639                 {
 640                         if (character > 255) {
 641                                 throw new ArgumentOutOfRangeException ("character");
 642                         }
 643
 644                         return "%" + hexUpperChars [((character & 0xf0) >> 4)]
 645                                    + hexUpperChars [((character & 0x0f))];
 646                 }
 647
 648                 public static char HexUnescape (string pattern, ref int index)
 649                 {
 650                         if (pattern == null)
 651                                 throw new ArgumentException ("pattern");
 652
 653                         if (index < 0 || index >= pattern.Length)
 654                                 throw new ArgumentOutOfRangeException ("index");
 655
 656                         int stage = 0;
 657                         int c = 0;
 658                         do {
 659                                 if (((index + 3) > pattern.Length) ||
 660                                     (pattern [index] != '%') ||
 661                                     !IsHexDigit (pattern [index + 1]) ||
 662                                     !IsHexDigit (pattern [index + 2]))
 663                                 {
 664                                         if (stage == 0)
 665                                                 return pattern [index++];
 666                                         break;
 667                                 }
 668
 669                                 index++;
 670                                 int msb = FromHex (pattern [index++]);
 671                                 int lsb = FromHex (pattern [index++]);
 672                                 int b = (msb << 4) + lsb;
 673
 674                                 if (stage == 0) {
 675                                         if (b < 0xc0)
 676                                                 return (char) b;
 677                                         else if (b < 0xE0) {
 678                                                 c = b - 0xc0;
 679                                                 stage = 2;
 680                                         } else if (b < 0xF0) {
 681                                                 c = b - 0xe0;
 682                                                 stage = 3;
 683                                         } else if (b < 0xF8) {
 684                                                 c = b - 0xf0;
 685                                                 stage = 4;
 686                                         } else if (b < 0xFB) {
 687                                                 c = b - 0xf8;
 688                                                 stage = 5;
 689                                         } else if (b < 0xFE) {
 690                                                 c = b - 0xfc;
 691                                                 stage = 6;
 692                                         }
 693                                         c <<= (stage - 1) * 6;
 694                                 }
 695                                 else
 696                                         c += (b - 0x80) << ((stage - 1) * 6);
 697 //Console.WriteLine ("stage {0}: {5:X04} <-- {1:X02}|{2:X01},{3:X01} {4}", new object [] {stage, b, msb, lsb, pattern.Substring (index), c});
 698                                 stage--;
 699                         } while (stage > 0);
 700
 701                         return (char) c;
 702                 }
 703
 704                 public static bool IsHexDigit (char digit)
 705                 {
 706                         return (('0' <= digit && digit <= '9') ||
 707                                 ('a' <= digit && digit <= 'f') ||
 708                                 ('A' <= digit && digit <= 'F'));
 709                 }
 710
 711                 public static bool IsHexEncoding (string pattern, int index)
 712                 {
 713                         if ((index + 3) > pattern.Length)
 714                                 return false;
 715
 716                         return ((pattern [index++] == '%') &&
 717                                 IsHexDigit (pattern [index++]) &&
 718                                 IsHexDigit (pattern [index]));
 719                 }
 720
 721                 public string MakeRelative (Uri toUri)
 722                 {
 723                         if ((this.Scheme != toUri.Scheme) ||
 724                             (this.Authority != toUri.Authority))
 725                                 return toUri.ToString ();
 726
 727                         if (this.path == toUri.path)
 728                                 return String.Empty;
 729
 730                         string [] segments = this.Segments;
 731                         string [] segments2 = toUri.Segments;
 732
 733                         int k = 0;
 734                         int max = System.Math.Min (segments.Length, segments2.Length);
 735                         for (; k < max; k++)
 736                                 if (segments [k] != segments2 [k])
 737                                         break;
 738
 739                         string result = String.Empty;
 740                         for (int i = k + 1; i < segments.Length; i++)
 741                                 result += "../";
 742                         for (int i = k; i < segments2.Length; i++)
 743                                 result += segments2 [i];
 744
 745                         return result;
 746                 }
 747
 748                 public override string ToString ()
 749                 {
 750                         if (cachedToString != null)
 751                                 return cachedToString;
 752                         string q = query.StartsWith ("?") ? '?' + Unescape (query.Substring (1)) : Unescape (query);
 753                         cachedToString = Unescape (GetLeftPart (UriPartial.Path), true) + q + fragment;
 754                         return cachedToString;
 755                 }
 756
 757 /*              void ISerializable.GetObjectData (SerializationInfo info,
 758                                           StreamingContext context)
 759                 {
 760                         info.AddValue ("AbsoluteUri", this.AbsoluteUri);
 761                 }*/
 762
 763
 764                 // Internal Methods
 765
 766                 protected void Escape ()
 767                 {
 768                         path = EscapeString (path);
 769                 }
 770
 771                 protected static string EscapeString (string str)
 772                 {
 773                         return EscapeString (str, false, true, true);
 774                 }
 775
 776                 internal static string EscapeString (string str, bool escapeReserved, bool escapeHex, bool escapeBrackets)
 777                 {
 778                         if (str == null)
 779                                 return String.Empty;
 780
 781                         StringBuilder s = new StringBuilder ();
 782                         int len = str.Length;
 783                         for (int i = 0; i < len; i++) {
 784                                 // reserved    = ";" | "/" | "?" | ":" | "@" | "&" | "=" | "+" | "$" | ","
 785                                 // mark        = "-" | "_" | "." | "!" | "~" | "*" | "'" | "(" | ")"
 786                                 // control     = <US-ASCII coded characters 00-1F and 7F hexadecimal>
 787                                 // space       = <US-ASCII coded character 20 hexadecimal>
 788                                 // delims      = "<" | ">" | "#" | "%" | <">
 789                                 // unwise      = "{" | "}" | "|" | "\" | "^" | "[" | "]" | "`"
 790
 791                                 // check for escape code already placed in str,
 792                                 // i.e. for encoding that follows the pattern
 793                                 // "%hexhex" in a string, where "hex" is a digit from 0-9
 794                                 // or a letter from A-F (case-insensitive).
 795                                 if (IsHexEncoding (str,i)) {
 796                                         // if ,yes , copy it as is
 797                                         s.Append(str.Substring (i, 3));
 798                                         i += 2;
 799                                         continue;
 800                                 }
 801
 802                                 byte [] data = Encoding.UTF8.GetBytes (new char[] {str[i]});
 803                                 int length = data.Length;
 804                                 for (int j = 0; j < length; j++) {
 805                                         char c = (char) data [j];
 806                                         if ((c <= 0x20) || (c >= 0x7f) ||
 807                                             ("<>%\"{}|\\^`".IndexOf (c) != -1) ||
 808                                             (escapeHex && (c == '#')) ||
 809                                             (escapeBrackets && (c == '[' || c == ']')) ||
 810                                             (escapeReserved && (";/?:@&=+$,".IndexOf (c) != -1))) {
 811                                                 s.Append (HexEscape (c));
 812                                                 continue;
 813                                         }
 814                                         s.Append (c);
 815                                 }
 816                         }
 817
 818                         return s.ToString ();
 819                 }
 820
 821                 // This method is called from .ctor(). When overriden, we can
 822                 // avoid the "absolute uri" constraints of the .ctor() by
 823                 // overriding with custom code.
 824                 protected void Parse ()
 825                 {
 826                         Parse (source);
 827
 828                         if (userEscaped)
 829                                 return;
 830
 831                         host = EscapeString (host, false, true, false);
 832                         path = EscapeString (path);
 833                 }
 834
 835                 protected string Unescape (string str)
 836                 {
 837                         return Unescape (str, false);
 838                 }
 839
 840                 internal string Unescape (string str, bool excludeSharp)
 841                 {
 842                         if (str == null)
 843                                 return String.Empty;
 844                         StringBuilder s = new StringBuilder ();
 845                         int len = str.Length;
 846                         for (int i = 0; i < len; i++) {
 847                                 char c = str [i];
 848                                 if (c == '%') {
 849                                         char x = HexUnescape (str, ref i);
 850                                         if (excludeSharp && x == '#')
 851                                                 s.Append ("%23");
 852                                         else
 853                                                 s.Append (x);
 854                                         i--;
 855                                 } else
 856                                         s.Append (c);
 857                         }
 858                         return s.ToString ();
 859                 }
 860
 861
 862                 // Private Methods
 863
 864                 private void ParseAsWindowsUNC (string uriString)
 865                 {
 866                         scheme = UriSchemeFile;
 867                         port = -1;
 868                         fragment = String.Empty;
 869                         query = String.Empty;
 870                         isUnc = true;
 871
 872                         uriString = uriString.TrimStart (new char [] {'\\'});
 873                         int pos = uriString.IndexOf ('\\');
 874                         if (pos > 0) {
 875                                 path = uriString.Substring (pos);
 876                                 host = uriString.Substring (0, pos);
 877                         } else { // "\\\\server"
 878                                 host = uriString;
 879                                 path = String.Empty;
 880                         }
 881                         path = path.Replace ("\\", "/");
 882                 }
 883
 884                 private void ParseAsWindowsAbsoluteFilePath (string uriString)
 885                 {
 886                         if (uriString.Length > 2 && uriString [2] != '\\'
 887                                         && uriString [2] != '/')
 888                                 throw new FormatException ("Relative file path is not allowed.");
 889                         scheme = UriSchemeFile;
 890                         host = String.Empty;
 891                         port = -1;
 892                         path = uriString.Replace ("\\", "/");
 893                         fragment = String.Empty;
 894                         query = String.Empty;
 895                 }
 896
 897                 private void ParseAsUnixAbsoluteFilePath (string uriString)
 898                 {
 899                         isUnixFilePath = true;
 900                         scheme = UriSchemeFile;
 901                         port = -1;
 902                         fragment = String.Empty;
 903                         query = String.Empty;
 904                         host = String.Empty;
 905                         path = null;
 906
 907                         if (uriString.StartsWith ("//")) {
 908                                 uriString = uriString.TrimStart (new char [] {'/'});
 909                                 // Now we don't regard //foo/bar as "foo" host.
 910                                 /*
 911                                 int pos = uriString.IndexOf ('/');
 912                                 if (pos > 0) {
 913                                         path = '/' + uriString.Substring (pos + 1);
 914                                         host = uriString.Substring (0, pos);
 915                                 } else { // "///server"
 916                                         host = uriString;
 917                                         path = String.Empty;
 918                                 }
 919                                 */
 920                                 path = '/' + uriString;
 921                         }
 922                         if (path == null)
 923                                 path = uriString;
 924                 }
 925
 926                 // this parse method is as relaxed as possible about the format
 927                 // it will hardly ever throw a UriFormatException
 928                 private void Parse (string uriString)
 929                 {
 930                         //
 931                         // From RFC 2396 :
 932                         //
 933                         //      ^(([^:/?#]+):)?(//([^/?#]*))?([^?#]*)(\?([^#]*))?(#(.*))?
 934                         //       12            3  4          5       6  7        8 9
 935                         //
 936
 937                         if (uriString == null)
 938                                 throw new ArgumentNullException ("uriString");
 939
 940                         int len = uriString.Length;
 941                         if (len <= 1)
 942                                 throw new FormatException ();
 943
 944                         int pos = 0;
 945
 946                         // 1, 2
 947                         // Identify Windows path, unix path, or standard URI.
 948                         pos = uriString.IndexOf (':');
 949                         if (pos < 0) {
 950                                 // It must be Unix file path or Windows UNC
 951                                 if (uriString [0] == '/')
 952                                         ParseAsUnixAbsoluteFilePath (uriString);
 953                                 else if (uriString.StartsWith ("\\\\"))
 954                                         ParseAsWindowsUNC (uriString);
 955                                 else
 956                                         throw new FormatException ("URI scheme was not recognized, nor input string is not recognized as an absolute file path.");
 957                                 return;
 958                         }
 959                         else if (pos == 1) {
 960                                 if (!Char.IsLetter (uriString [0]))
 961                                         throw new FormatException ("URI scheme must start with alphabet character.");
 962                                 // This means 'a:' == windows full path.
 963                                 ParseAsWindowsAbsoluteFilePath (uriString);
 964                                 return;
 965                         }
 966
 967                         // scheme
 968                         scheme = uriString.Substring (0, pos).ToLower (CultureInfo.InvariantCulture);
 969                         // Check scheme name characters as specified in RFC2396.
 970                         if (!Char.IsLetter (scheme [0]))
 971                                         throw new FormatException ("URI scheme must start with alphabet character.");
 972                         for (int i = 1; i < scheme.Length; i++) {
 973                                 if (!Char.IsLetterOrDigit (scheme, i)) {
 974                                         switch (scheme [i]) {
 975                                         case '+':
 976                                         case '-':
 977                                         case '.':
 978                                                 break;
 979                                         default:
 980                                                 throw new FormatException ("URI scheme must consist of one of alphabet, digits, '+', '-' or '.' character.");
 981                                         }
 982                                 }
 983                         }
 984                         uriString = uriString.Substring (pos + 1);
 985
 986                         // 8 fragment
 987                         pos = uriString.IndexOf ('#');
 988                         if (!IsUnc && pos != -1) {
 989                                 fragment = uriString.Substring (pos);
 990                                 uriString = uriString.Substring (0, pos);
 991                         }
 992
 993                         // 6 query
 994                         pos = uriString.IndexOf ('?');
 995                         if (pos != -1) {
 996                                 query = uriString.Substring (pos);
 997                                 uriString = uriString.Substring (0, pos);
 998                                 if (!userEscaped)
 999                                         query = EscapeString (query);
1000                         }
1001
1002                         // 3
1003                         bool unixAbsPath = scheme == UriSchemeFile && uriString.StartsWith ("///");
1004                         if (uriString.StartsWith ("//")) {
1005                                 if (uriString.StartsWith ("////"))
1006                                         unixAbsPath = false;
1007                                 uriString = uriString.TrimStart (new char [] {'/'});
1008                                 if (uriString.Length > 1 && uriString [1] == ':')
1009                                         unixAbsPath = false;
1010                         } else if (!IsPredefinedScheme (scheme)) {
1011                                 path = uriString;
1012                                 isOpaquePart = true;
1013                                 return;
1014                         }
1015
1016                         // 5 path
1017                         pos = uriString.IndexOfAny (new char[] {'/'});
1018                         if (unixAbsPath)
1019                                 pos = -1;
1020                         if (pos == -1) {
1021                                 if ((scheme != Uri.UriSchemeMailto) &&
1022                                     (scheme != Uri.UriSchemeNews) &&
1023                                         (scheme != Uri.UriSchemeFile))
1024                                         path = "/";
1025                         } else {
1026                                 path = uriString.Substring (pos);
1027                                 uriString = uriString.Substring (0, pos);
1028                         }
1029
1030                         // 4.a user info
1031                         pos = uriString.IndexOf ("@");
1032                         if (pos != -1) {
1033                                 userinfo = uriString.Substring (0, pos);
1034                                 uriString = uriString.Remove (0, pos + 1);
1035                         }
1036
1037                         // 4.b port
1038                         port = -1;
1039                         pos = uriString.LastIndexOf (":");
1040                         if (unixAbsPath)
1041                                 pos = -1;
1042                         if (pos != -1 && pos != (uriString.Length - 1)) {
1043                                 string portStr = uriString.Remove (0, pos + 1);
1044                                 if (portStr.Length > 1 && portStr [portStr.Length - 1] != ']') {
1045                                         try {
1046                                                 port = (int) UInt32.Parse (portStr, CultureInfo.InvariantCulture);
1047                                                 uriString = uriString.Substring (0, pos);
1048                                         } catch (Exception) {
1049                                                 throw new FormatException ("Invalid URI: invalid port number");
1050                                         }
1051                                 }
1052                         }
1053                         if (port == -1) {
1054                                 port = GetDefaultPort (scheme);
1055                         }
1056
1057                         // 4 authority
1058                         host = uriString;
1059 /*                      if (host.Length > 1 && host [0] == '[' && host [host.Length - 1] == ']') {
1060                                 try {
1061                                         host = "[" + IPv6Address.Parse (host).ToString () + "]";
1062                                 } catch (Exception) {
1063                                         throw new FormatException ("Invalid URI: The hostname could not be parsed");
1064                                 }
1065                         }*/
1066
1067                         if (unixAbsPath) {
1068                                 path = '/' + uriString;
1069                                 host = String.Empty;
1070                         } else if (host.Length == 2 && host [1] == ':') {
1071                                 // windows filepath
1072                                 path = host + path;
1073                                 host = String.Empty;
1074                         } else if (isUnixFilePath) {
1075                                 uriString = "//" + uriString;
1076                                 host = String.Empty;
1077                         } else if (host.Length == 0) {
1078                                 throw new FormatException ("Invalid URI: The hostname could not be parsed");
1079                         } else if (scheme == UriSchemeFile) {
1080                                 isUnc = true;
1081                         }
1082
1083                         if ((scheme != Uri.UriSchemeMailto) &&
1084                                         (scheme != Uri.UriSchemeNews) &&
1085                                         (scheme != Uri.UriSchemeFile))
1086
1087                         if (reduce)
1088                                 path = Reduce (path);
1089                 }
1090
1091                 private static string Reduce (string path)
1092                 {
1093                         path = path.Replace ('\\','/');
1094                         string [] parts = path.Split ('/');
1095                         ArrayList result = new ArrayList ();
1096
1097                         int end = parts.Length;
1098                         for (int i = 0; i < end; i++) {
1099                                 string current = parts [i];
1100                                 if (current.Length == 0 || current == "." )
1101                                         continue;
1102
1103                                 if (current == "..") {
1104                                         if (result.Count == 0) {
1105                                                 if (i == 1) // see bug 52599
1106                                                         continue;
1107                                                 throw new Exception ("Invalid path.");
1108                                         }
1109
1110                                         result.RemoveAt (result.Count - 1);
1111                                         continue;
1112                                 }
1113
1114                                 result.Add (current);
1115                         }
1116
1117                         if (result.Count == 0)
1118                                 return "/";
1119
1120                         result.Insert (0, String.Empty);
1121
1122                         string res = String.Join ("/", (string []) result.ToArray (typeof (string)));
1123                         if (path.EndsWith ("/"))
1124                                 res += '/';
1125
1126                         return res;
1127                 }
1128
1129                 private struct UriScheme
1130                 {
1131                         public string scheme;
1132                         public string delimiter;
1133                         public int defaultPort;
1134
1135                         public UriScheme (string s, string d, int p)
1136                         {
1137                                 scheme = s;
1138                                 delimiter = d;
1139                                 defaultPort = p;
1140                         }
1141                 };
1142
1143                 static UriScheme [] schemes = new UriScheme [] {
1144                         new UriScheme (UriSchemeHttp, SchemeDelimiter, 80),
1145                         new UriScheme (UriSchemeHttps, SchemeDelimiter, 443),
1146                         new UriScheme (UriSchemeFtp, SchemeDelimiter, 21),
1147                         new UriScheme (UriSchemeFile, SchemeDelimiter, -1),
1148                         new UriScheme (UriSchemeMailto, ":", 25),
1149                         new UriScheme (UriSchemeNews, ":", -1),
1150                         new UriScheme (UriSchemeNntp, SchemeDelimiter, 119),
1151                         new UriScheme (UriSchemeGopher, SchemeDelimiter, 70),
1152                 };
1153
1154                 internal static string GetSchemeDelimiter (string scheme)
1155                 {
1156                         for (int i = 0; i < schemes.Length; i++)
1157                                 if (schemes [i].scheme == scheme)
1158                                         return schemes [i].delimiter;
1159                         return Uri.SchemeDelimiter;
1160                 }
1161
1162                 internal static int GetDefaultPort (string scheme)
1163                 {
1164                         for (int i = 0; i < schemes.Length; i++)
1165                                 if (schemes [i].scheme == scheme)
1166                                         return schemes [i].defaultPort;
1167                         return -1;
1168                 }
1169
1170                 private string GetOpaqueWiseSchemeDelimiter ()
1171                 {
1172                         if (isOpaquePart)
1173                                 return ":";
1174                         else
1175                                 return GetSchemeDelimiter (scheme);
1176                 }
1177
1178                 protected bool IsBadFileSystemCharacter (char ch)
1179                 {
1180                         // It does not always overlap with InvalidPathChars.
1181                         int chInt = (int) ch;
1182                         if (chInt < 32 || (chInt < 64 && chInt > 57))
1183                                 return true;
1184                         switch (chInt) {
1185                         case 0:
1186                         case 34: // "
1187                         case 38: // &
1188                         case 42: // *
1189                         case 44: // ,
1190                         case 47: // /
1191                         case 92: // \
1192                         case 94: // ^
1193                         case 124: // |
1194                                 return true;
1195                         }
1196
1197                         return false;
1198                 }
1199
1200
1201                 protected static bool IsExcludedCharacter (char ch)
1202                 {
1203                         if (ch <= 32 || ch >= 127)
1204                                 return true;
1205
1206                         if (ch == '"' || ch == '#' || ch == '%' || ch == '<' ||
1207                             ch == '>' || ch == '[' || ch == '\\' || ch == ']' ||
1208                             ch == '^' || ch == '`' || ch == '{' || ch == '|' ||
1209                             ch == '}')
1210                                 return true;
1211                         return false;
1212                 }
1213
1214                 private static bool IsPredefinedScheme (string scheme)
1215                 {
1216                         switch (scheme) {
1217                         case "http":
1218                         case "https":
1219                         case "file":
1220                         case "ftp":
1221                         case "nntp":
1222                         case "gopher":
1223                         case "mailto":
1224                         case "news":
1225                                 return true;
1226                         default:
1227                                 return false;
1228                         }
1229                 }
1230
1231                 protected bool IsReservedCharacter (char ch)
1232                 {
1233                         if (ch == '$' || ch == '&' || ch == '+' || ch == ',' ||
1234                             ch == '/' || ch == ':' || ch == ';' || ch == '=' ||
1235                             ch == '@')
1236                                 return true;
1237                         return false;
1238                 }
1239         }
1240 }