mcs/class/System.Web/System.Web/HttpUtility.cs

   1 //
   2 // System.Web.HttpUtility
   3 //
   4 // Authors:
   5 //   Patrik Torstensson (Patrik.Torstensson@labs2.com)
   6 //   Wictor Wilén (decode/encode functions) (wictor@ibizkit.se)
   7 //   Tim Coleman (tim@timcoleman.com)
   8 //   Gonzalo Paniagua Javier (gonzalo@ximian.com)
   9 //
  10 // Copyright (C) 2005 Novell, Inc (http://www.novell.com)
  11 //
  12 // Permission is hereby granted, free of charge, to any person obtaining
  13 // a copy of this software and associated documentation files (the
  14 // "Software"), to deal in the Software without restriction, including
  15 // without limitation the rights to use, copy, modify, merge, publish,
  16 // distribute, sublicense, and/or sell copies of the Software, and to
  17 // permit persons to whom the Software is furnished to do so, subject to
  18 // the following conditions:
  19 //
  20 // The above copyright notice and this permission notice shall be
  21 // included in all copies or substantial portions of the Software.
  22 //
  23 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  27 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  28 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  29 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  30 //
  31
  32 using System.Collections;
  33 using System.Collections.Specialized;
  34 using System.Globalization;
  35 using System.IO;
  36 using System.Security.Permissions;
  37 using System.Text;
  38 using System.Web.Util;
  39
  40 namespace System.Web {
  41
  42         // CAS - no InheritanceDemand here as the class is sealed
  43         [AspNetHostingPermission (SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
  44         public sealed class HttpUtility {
  45
  46                 #region Fields
  47
  48                 static Hashtable entities;
  49                 static object lock_ = new object ();
  50
  51                 #endregion // Fields
  52
  53                 static Hashtable Entities {
  54                         get {
  55                                 lock (lock_) {
  56                                         if (entities == null)
  57                                                 InitEntities ();
  58
  59                                         return entities;
  60                                 }
  61                         }
  62                 }
  63
  64                 #region Constructors
  65
  66                 static void InitEntities ()
  67                 {
  68                         // Build the hash table of HTML entity references.  This list comes
  69                         // from the HTML 4.01 W3C recommendation.
  70                         entities = new Hashtable ();
  71                         entities.Add ("nbsp", '\u00A0');
  72                         entities.Add ("iexcl", '\u00A1');
  73                         entities.Add ("cent", '\u00A2');
  74                         entities.Add ("pound", '\u00A3');
  75                         entities.Add ("curren", '\u00A4');
  76                         entities.Add ("yen", '\u00A5');
  77                         entities.Add ("brvbar", '\u00A6');
  78                         entities.Add ("sect", '\u00A7');
  79                         entities.Add ("uml", '\u00A8');
  80                         entities.Add ("copy", '\u00A9');
  81                         entities.Add ("ordf", '\u00AA');
  82                         entities.Add ("laquo", '\u00AB');
  83                         entities.Add ("not", '\u00AC');
  84                         entities.Add ("shy", '\u00AD');
  85                         entities.Add ("reg", '\u00AE');
  86                         entities.Add ("macr", '\u00AF');
  87                         entities.Add ("deg", '\u00B0');
  88                         entities.Add ("plusmn", '\u00B1');
  89                         entities.Add ("sup2", '\u00B2');
  90                         entities.Add ("sup3", '\u00B3');
  91                         entities.Add ("acute", '\u00B4');
  92                         entities.Add ("micro", '\u00B5');
  93                         entities.Add ("para", '\u00B6');
  94                         entities.Add ("middot", '\u00B7');
  95                         entities.Add ("cedil", '\u00B8');
  96                         entities.Add ("sup1", '\u00B9');
  97                         entities.Add ("ordm", '\u00BA');
  98                         entities.Add ("raquo", '\u00BB');
  99                         entities.Add ("frac14", '\u00BC');
 100                         entities.Add ("frac12", '\u00BD');
 101                         entities.Add ("frac34", '\u00BE');
 102                         entities.Add ("iquest", '\u00BF');
 103                         entities.Add ("Agrave", '\u00C0');
 104                         entities.Add ("Aacute", '\u00C1');
 105                         entities.Add ("Acirc", '\u00C2');
 106                         entities.Add ("Atilde", '\u00C3');
 107                         entities.Add ("Auml", '\u00C4');
 108                         entities.Add ("Aring", '\u00C5');
 109                         entities.Add ("AElig", '\u00C6');
 110                         entities.Add ("Ccedil", '\u00C7');
 111                         entities.Add ("Egrave", '\u00C8');
 112                         entities.Add ("Eacute", '\u00C9');
 113                         entities.Add ("Ecirc", '\u00CA');
 114                         entities.Add ("Euml", '\u00CB');
 115                         entities.Add ("Igrave", '\u00CC');
 116                         entities.Add ("Iacute", '\u00CD');
 117                         entities.Add ("Icirc", '\u00CE');
 118                         entities.Add ("Iuml", '\u00CF');
 119                         entities.Add ("ETH", '\u00D0');
 120                         entities.Add ("Ntilde", '\u00D1');
 121                         entities.Add ("Ograve", '\u00D2');
 122                         entities.Add ("Oacute", '\u00D3');
 123                         entities.Add ("Ocirc", '\u00D4');
 124                         entities.Add ("Otilde", '\u00D5');
 125                         entities.Add ("Ouml", '\u00D6');
 126                         entities.Add ("times", '\u00D7');
 127                         entities.Add ("Oslash", '\u00D8');
 128                         entities.Add ("Ugrave", '\u00D9');
 129                         entities.Add ("Uacute", '\u00DA');
 130                         entities.Add ("Ucirc", '\u00DB');
 131                         entities.Add ("Uuml", '\u00DC');
 132                         entities.Add ("Yacute", '\u00DD');
 133                         entities.Add ("THORN", '\u00DE');
 134                         entities.Add ("szlig", '\u00DF');
 135                         entities.Add ("agrave", '\u00E0');
 136                         entities.Add ("aacute", '\u00E1');
 137                         entities.Add ("acirc", '\u00E2');
 138                         entities.Add ("atilde", '\u00E3');
 139                         entities.Add ("auml", '\u00E4');
 140                         entities.Add ("aring", '\u00E5');
 141                         entities.Add ("aelig", '\u00E6');
 142                         entities.Add ("ccedil", '\u00E7');
 143                         entities.Add ("egrave", '\u00E8');
 144                         entities.Add ("eacute", '\u00E9');
 145                         entities.Add ("ecirc", '\u00EA');
 146                         entities.Add ("euml", '\u00EB');
 147                         entities.Add ("igrave", '\u00EC');
 148                         entities.Add ("iacute", '\u00ED');
 149                         entities.Add ("icirc", '\u00EE');
 150                         entities.Add ("iuml", '\u00EF');
 151                         entities.Add ("eth", '\u00F0');
 152                         entities.Add ("ntilde", '\u00F1');
 153                         entities.Add ("ograve", '\u00F2');
 154                         entities.Add ("oacute", '\u00F3');
 155                         entities.Add ("ocirc", '\u00F4');
 156                         entities.Add ("otilde", '\u00F5');
 157                         entities.Add ("ouml", '\u00F6');
 158                         entities.Add ("divide", '\u00F7');
 159                         entities.Add ("oslash", '\u00F8');
 160                         entities.Add ("ugrave", '\u00F9');
 161                         entities.Add ("uacute", '\u00FA');
 162                         entities.Add ("ucirc", '\u00FB');
 163                         entities.Add ("uuml", '\u00FC');
 164                         entities.Add ("yacute", '\u00FD');
 165                         entities.Add ("thorn", '\u00FE');
 166                         entities.Add ("yuml", '\u00FF');
 167                         entities.Add ("fnof", '\u0192');
 168                         entities.Add ("Alpha", '\u0391');
 169                         entities.Add ("Beta", '\u0392');
 170                         entities.Add ("Gamma", '\u0393');
 171                         entities.Add ("Delta", '\u0394');
 172                         entities.Add ("Epsilon", '\u0395');
 173                         entities.Add ("Zeta", '\u0396');
 174                         entities.Add ("Eta", '\u0397');
 175                         entities.Add ("Theta", '\u0398');
 176                         entities.Add ("Iota", '\u0399');
 177                         entities.Add ("Kappa", '\u039A');
 178                         entities.Add ("Lambda", '\u039B');
 179                         entities.Add ("Mu", '\u039C');
 180                         entities.Add ("Nu", '\u039D');
 181                         entities.Add ("Xi", '\u039E');
 182                         entities.Add ("Omicron", '\u039F');
 183                         entities.Add ("Pi", '\u03A0');
 184                         entities.Add ("Rho", '\u03A1');
 185                         entities.Add ("Sigma", '\u03A3');
 186                         entities.Add ("Tau", '\u03A4');
 187                         entities.Add ("Upsilon", '\u03A5');
 188                         entities.Add ("Phi", '\u03A6');
 189                         entities.Add ("Chi", '\u03A7');
 190                         entities.Add ("Psi", '\u03A8');
 191                         entities.Add ("Omega", '\u03A9');
 192                         entities.Add ("alpha", '\u03B1');
 193                         entities.Add ("beta", '\u03B2');
 194                         entities.Add ("gamma", '\u03B3');
 195                         entities.Add ("delta", '\u03B4');
 196                         entities.Add ("epsilon", '\u03B5');
 197                         entities.Add ("zeta", '\u03B6');
 198                         entities.Add ("eta", '\u03B7');
 199                         entities.Add ("theta", '\u03B8');
 200                         entities.Add ("iota", '\u03B9');
 201                         entities.Add ("kappa", '\u03BA');
 202                         entities.Add ("lambda", '\u03BB');
 203                         entities.Add ("mu", '\u03BC');
 204                         entities.Add ("nu", '\u03BD');
 205                         entities.Add ("xi", '\u03BE');
 206                         entities.Add ("omicron", '\u03BF');
 207                         entities.Add ("pi", '\u03C0');
 208                         entities.Add ("rho", '\u03C1');
 209                         entities.Add ("sigmaf", '\u03C2');
 210                         entities.Add ("sigma", '\u03C3');
 211                         entities.Add ("tau", '\u03C4');
 212                         entities.Add ("upsilon", '\u03C5');
 213                         entities.Add ("phi", '\u03C6');
 214                         entities.Add ("chi", '\u03C7');
 215                         entities.Add ("psi", '\u03C8');
 216                         entities.Add ("omega", '\u03C9');
 217                         entities.Add ("thetasym", '\u03D1');
 218                         entities.Add ("upsih", '\u03D2');
 219                         entities.Add ("piv", '\u03D6');
 220                         entities.Add ("bull", '\u2022');
 221                         entities.Add ("hellip", '\u2026');
 222                         entities.Add ("prime", '\u2032');
 223                         entities.Add ("Prime", '\u2033');
 224                         entities.Add ("oline", '\u203E');
 225                         entities.Add ("frasl", '\u2044');
 226                         entities.Add ("weierp", '\u2118');
 227                         entities.Add ("image", '\u2111');
 228                         entities.Add ("real", '\u211C');
 229                         entities.Add ("trade", '\u2122');
 230                         entities.Add ("alefsym", '\u2135');
 231                         entities.Add ("larr", '\u2190');
 232                         entities.Add ("uarr", '\u2191');
 233                         entities.Add ("rarr", '\u2192');
 234                         entities.Add ("darr", '\u2193');
 235                         entities.Add ("harr", '\u2194');
 236                         entities.Add ("crarr", '\u21B5');
 237                         entities.Add ("lArr", '\u21D0');
 238                         entities.Add ("uArr", '\u21D1');
 239                         entities.Add ("rArr", '\u21D2');
 240                         entities.Add ("dArr", '\u21D3');
 241                         entities.Add ("hArr", '\u21D4');
 242                         entities.Add ("forall", '\u2200');
 243                         entities.Add ("part", '\u2202');
 244                         entities.Add ("exist", '\u2203');
 245                         entities.Add ("empty", '\u2205');
 246                         entities.Add ("nabla", '\u2207');
 247                         entities.Add ("isin", '\u2208');
 248                         entities.Add ("notin", '\u2209');
 249                         entities.Add ("ni", '\u220B');
 250                         entities.Add ("prod", '\u220F');
 251                         entities.Add ("sum", '\u2211');
 252                         entities.Add ("minus", '\u2212');
 253                         entities.Add ("lowast", '\u2217');
 254                         entities.Add ("radic", '\u221A');
 255                         entities.Add ("prop", '\u221D');
 256                         entities.Add ("infin", '\u221E');
 257                         entities.Add ("ang", '\u2220');
 258                         entities.Add ("and", '\u2227');
 259                         entities.Add ("or", '\u2228');
 260                         entities.Add ("cap", '\u2229');
 261                         entities.Add ("cup", '\u222A');
 262                         entities.Add ("int", '\u222B');
 263                         entities.Add ("there4", '\u2234');
 264                         entities.Add ("sim", '\u223C');
 265                         entities.Add ("cong", '\u2245');
 266                         entities.Add ("asymp", '\u2248');
 267                         entities.Add ("ne", '\u2260');
 268                         entities.Add ("equiv", '\u2261');
 269                         entities.Add ("le", '\u2264');
 270                         entities.Add ("ge", '\u2265');
 271                         entities.Add ("sub", '\u2282');
 272                         entities.Add ("sup", '\u2283');
 273                         entities.Add ("nsub", '\u2284');
 274                         entities.Add ("sube", '\u2286');
 275                         entities.Add ("supe", '\u2287');
 276                         entities.Add ("oplus", '\u2295');
 277                         entities.Add ("otimes", '\u2297');
 278                         entities.Add ("perp", '\u22A5');
 279                         entities.Add ("sdot", '\u22C5');
 280                         entities.Add ("lceil", '\u2308');
 281                         entities.Add ("rceil", '\u2309');
 282                         entities.Add ("lfloor", '\u230A');
 283                         entities.Add ("rfloor", '\u230B');
 284                         entities.Add ("lang", '\u2329');
 285                         entities.Add ("rang", '\u232A');
 286                         entities.Add ("loz", '\u25CA');
 287                         entities.Add ("spades", '\u2660');
 288                         entities.Add ("clubs", '\u2663');
 289                         entities.Add ("hearts", '\u2665');
 290                         entities.Add ("diams", '\u2666');
 291                         entities.Add ("quot", '\u0022');
 292                         entities.Add ("amp", '\u0026');
 293                         entities.Add ("lt", '\u003C');
 294                         entities.Add ("gt", '\u003E');
 295                         entities.Add ("OElig", '\u0152');
 296                         entities.Add ("oelig", '\u0153');
 297                         entities.Add ("Scaron", '\u0160');
 298                         entities.Add ("scaron", '\u0161');
 299                         entities.Add ("Yuml", '\u0178');
 300                         entities.Add ("circ", '\u02C6');
 301                         entities.Add ("tilde", '\u02DC');
 302                         entities.Add ("ensp", '\u2002');
 303                         entities.Add ("emsp", '\u2003');
 304                         entities.Add ("thinsp", '\u2009');
 305                         entities.Add ("zwnj", '\u200C');
 306                         entities.Add ("zwj", '\u200D');
 307                         entities.Add ("lrm", '\u200E');
 308                         entities.Add ("rlm", '\u200F');
 309                         entities.Add ("ndash", '\u2013');
 310                         entities.Add ("mdash", '\u2014');
 311                         entities.Add ("lsquo", '\u2018');
 312                         entities.Add ("rsquo", '\u2019');
 313                         entities.Add ("sbquo", '\u201A');
 314                         entities.Add ("ldquo", '\u201C');
 315                         entities.Add ("rdquo", '\u201D');
 316                         entities.Add ("bdquo", '\u201E');
 317                         entities.Add ("dagger", '\u2020');
 318                         entities.Add ("Dagger", '\u2021');
 319                         entities.Add ("permil", '\u2030');
 320                         entities.Add ("lsaquo", '\u2039');
 321                         entities.Add ("rsaquo", '\u203A');
 322                         entities.Add ("euro", '\u20AC');
 323                 }
 324
 325                 public HttpUtility ()
 326                 {
 327                 }
 328
 329                 #endregion // Constructors
 330
 331                 #region Methods
 332
 333                 public static void HtmlAttributeEncode (string s, TextWriter output)
 334                 {
 335                         output.Write(HtmlAttributeEncode(s));
 336                 }
 337
 338                 public static string HtmlAttributeEncode (string s)
 339                 {
 340                         if (null == s)
 341                                 return null;
 342
 343                         if (s.IndexOf ('&') == -1 && s.IndexOf ('"') == -1)
 344                                 return s;
 345
 346                         StringBuilder output = new StringBuilder ();
 347                         foreach (char c in s)
 348                                 switch (c) {
 349                                 case '&' :
 350                                         output.Append ("&amp;");
 351                                         break;
 352                                 case '"' :
 353                                         output.Append ("&quot;");
 354                                         break;
 355                                 default:
 356                                         output.Append (c);
 357                                         break;
 358                                 }
 359
 360                         return output.ToString();
 361                 }
 362
 363                 public static string UrlDecode (string str)
 364                 {
 365                         return UrlDecode(str, Encoding.UTF8);
 366                 }
 367
 368                 private static char [] GetChars (MemoryStream b, Encoding e)
 369                 {
 370                         return e.GetChars (b.GetBuffer (), 0, (int) b.Length);
 371                 }
 372
 373                 public static string UrlDecode (string s, Encoding e)
 374                 {
 375                         if (null == s)
 376                                 return null;
 377
 378                         if (s.IndexOf ('%') == -1 && s.IndexOf ('+') == -1)
 379                                 return s;
 380
 381                         if (e == null)
 382                                 e = Encoding.UTF8;
 383
 384                         StringBuilder output = new StringBuilder ();
 385                         long len = s.Length;
 386                         MemoryStream bytes = new MemoryStream ();
 387                         int xchar;
 388
 389                         for (int i = 0; i < len; i++) {
 390                                 if (s [i] == '%' && i + 2 < len && s [i + 1] != '%') {
 391                                         if (s [i + 1] == 'u' && i + 5 < len) {
 392                                                 if (bytes.Length > 0) {
 393                                                         output.Append (GetChars (bytes, e));
 394                                                         bytes.SetLength (0);
 395                                                 }
 396
 397                                                 xchar = GetChar (s, i + 2, 4);
 398                                                 if (xchar != -1) {
 399                                                         output.Append ((char) xchar);
 400                                                         i += 5;
 401                                                 } else {
 402                                                         output.Append ('%');
 403                                                 }
 404                                         } else if ((xchar = GetChar (s, i + 1, 2)) != -1) {
 405                                                 bytes.WriteByte ((byte) xchar);
 406                                                 i += 2;
 407                                         } else {
 408                                                 output.Append ('%');
 409                                         }
 410                                         continue;
 411                                 }
 412
 413                                 if (bytes.Length > 0) {
 414                                         output.Append (GetChars (bytes, e));
 415                                         bytes.SetLength (0);
 416                                 }
 417
 418                                 if (s [i] == '+') {
 419                                         output.Append (' ');
 420                                 } else {
 421                                         output.Append (s [i]);
 422                                 }
 423                         }
 424
 425                         if (bytes.Length > 0) {
 426                                 output.Append (GetChars (bytes, e));
 427                         }
 428
 429                         bytes = null;
 430                         return output.ToString ();
 431                 }
 432
 433                 public static string UrlDecode (byte [] bytes, Encoding e)
 434                 {
 435                         if (bytes == null)
 436                                 return null;
 437
 438                         return UrlDecode (bytes, 0, bytes.Length, e);
 439                 }
 440
 441                 private static int GetInt (byte b)
 442                 {
 443                         char c = (char) b;
 444                         if (c >= '0' && c <= '9')
 445                                 return c - '0';
 446
 447                         if (c >= 'a' && c <= 'f')
 448                                 return c - 'a' + 10;
 449
 450                         if (c >= 'A' && c <= 'F')
 451                                 return c - 'A' + 10;
 452
 453                         return -1;
 454                 }
 455
 456                 private static int GetChar (byte [] bytes, int offset, int length)
 457                 {
 458                         int value = 0;
 459                         int end = length + offset;
 460                         for (int i = offset; i < end; i++) {
 461                                 int current = GetInt (bytes [i]);
 462                                 if (current == -1)
 463                                         return -1;
 464                                 value = (value << 4) + current;
 465                         }
 466
 467                         return value;
 468                 }
 469
 470                 private static int GetChar (string str, int offset, int length)
 471                 {
 472                         int val = 0;
 473                         int end = length + offset;
 474                         for (int i = offset; i < end; i++) {
 475                                 char c = str [i];
 476                                 if (c > 127)
 477                                         return -1;
 478
 479                                 int current = GetInt ((byte) c);
 480                                 if (current == -1)
 481                                         return -1;
 482                                 val = (val << 4) + current;
 483                         }
 484
 485                         return val;
 486                 }
 487
 488                 public static string UrlDecode (byte [] bytes, int offset, int count, Encoding e)
 489                 {
 490                         if (bytes == null)
 491                                 return null;
 492                         if (count == 0)
 493                                 return String.Empty;
 494
 495                         if (bytes == null)
 496                                 throw new ArgumentNullException ("bytes");
 497
 498                         if (offset < 0 || offset > bytes.Length)
 499                                 throw new ArgumentOutOfRangeException ("offset");
 500
 501                         if (count < 0 || offset + count > bytes.Length)
 502                                 throw new ArgumentOutOfRangeException ("count");
 503
 504                         StringBuilder output = new StringBuilder ();
 505                         MemoryStream acc = new MemoryStream ();
 506
 507                         int end = count + offset;
 508                         int xchar;
 509                         for (int i = offset; i < end; i++) {
 510                                 if (bytes [i] == '%' && i + 2 < count && bytes [i + 1] != '%') {
 511                                         if (bytes [i + 1] == (byte) 'u' && i + 5 < end) {
 512                                                 if (acc.Length > 0) {
 513                                                         output.Append (GetChars (acc, e));
 514                                                         acc.SetLength (0);
 515                                                 }
 516                                                 xchar = GetChar (bytes, i + 2, 4);
 517                                                 if (xchar != -1) {
 518                                                         output.Append ((char) xchar);
 519                                                         i += 5;
 520                                                         continue;
 521                                                 }
 522                                         } else if ((xchar = GetChar (bytes, i + 1, 2)) != -1) {
 523                                                 acc.WriteByte ((byte) xchar);
 524                                                 i += 2;
 525                                                 continue;
 526                                         }
 527                                 }
 528
 529                                 if (acc.Length > 0) {
 530                                         output.Append (GetChars (acc, e));
 531                                         acc.SetLength (0);
 532                                 }
 533
 534                                 if (bytes [i] == '+') {
 535                                         output.Append (' ');
 536                                 } else {
 537                                         output.Append ((char) bytes [i]);
 538                                 }
 539                         }
 540
 541                         if (acc.Length > 0) {
 542                                 output.Append (GetChars (acc, e));
 543                         }
 544
 545                         acc = null;
 546                         return output.ToString ();
 547                 }
 548
 549                 public static byte [] UrlDecodeToBytes (byte [] bytes)
 550                 {
 551                         if (bytes == null)
 552                                 return null;
 553
 554                         return UrlDecodeToBytes (bytes, 0, bytes.Length);
 555                 }
 556
 557                 public static byte [] UrlDecodeToBytes (string str)
 558                 {
 559                         return UrlDecodeToBytes (str, Encoding.UTF8);
 560                 }
 561
 562                 public static byte [] UrlDecodeToBytes (string str, Encoding e)
 563                 {
 564                         if (str == null)
 565                                 return null;
 566
 567                         if (e == null)
 568                                 throw new ArgumentNullException ("e");
 569
 570                         return UrlDecodeToBytes (e.GetBytes (str));
 571                 }
 572
 573                 public static byte [] UrlDecodeToBytes (byte [] bytes, int offset, int count)
 574                 {
 575                         if (bytes == null)
 576                                 return null;
 577                         if (count == 0)
 578                                 return new byte [0];
 579
 580                         int len = bytes.Length;
 581                         if (offset < 0 || offset >= len)
 582                                 throw new ArgumentOutOfRangeException("offset");
 583
 584                         if (count < 0 || offset > len - count)
 585                                 throw new ArgumentOutOfRangeException("count");
 586
 587                         MemoryStream result = new MemoryStream ();
 588                         int end = offset + count;
 589                         for (int i = offset; i < end; i++){
 590                                 char c = (char) bytes [i];
 591                                 if (c == '+') {
 592                                         c = ' ';
 593                                 } else if (c == '%' && i < end - 2) {
 594                                         int xchar = GetChar (bytes, i + 1, 2);
 595                                         if (xchar != -1) {
 596                                                 c = (char) xchar;
 597                                                 i += 2;
 598                                         }
 599                                 }
 600                                 result.WriteByte ((byte) c);
 601                         }
 602
 603                         return result.ToArray ();
 604                 }
 605
 606                 public static string UrlEncode(string str)
 607                 {
 608                         return UrlEncode(str, Encoding.UTF8);
 609                 }
 610
 611                 public static string UrlEncode (string s, Encoding Enc)
 612                 {
 613                         if (s == null)
 614                                 return null;
 615
 616                         if (s == "")
 617                                 return "";
 618
 619                         byte [] bytes = Enc.GetBytes (s);
 620                         return Encoding.ASCII.GetString (UrlEncodeToBytes (bytes, 0, bytes.Length));
 621                 }
 622
 623                 public static string UrlEncode (byte [] bytes)
 624                 {
 625                         if (bytes == null)
 626                                 return null;
 627
 628                         if (bytes.Length == 0)
 629                                 return "";
 630
 631                         return Encoding.ASCII.GetString (UrlEncodeToBytes (bytes, 0, bytes.Length));
 632                 }
 633
 634                 public static string UrlEncode (byte [] bytes, int offset, int count)
 635                 {
 636                         if (bytes == null)
 637                                 return null;
 638
 639                         if (bytes.Length == 0)
 640                                 return "";
 641
 642                         return Encoding.ASCII.GetString (UrlEncodeToBytes (bytes, offset, count));
 643                 }
 644
 645                 public static byte [] UrlEncodeToBytes (string str)
 646                 {
 647                         return UrlEncodeToBytes (str, Encoding.UTF8);
 648                 }
 649
 650                 public static byte [] UrlEncodeToBytes (string str, Encoding e)
 651                 {
 652                         if (str == null)
 653                                 return null;
 654
 655                         if (str == "")
 656                                 return new byte [0];
 657
 658                         byte [] bytes = e.GetBytes (str);
 659                         return UrlEncodeToBytes (bytes, 0, bytes.Length);
 660                 }
 661
 662                 public static byte [] UrlEncodeToBytes (byte [] bytes)
 663                 {
 664                         if (bytes == null)
 665                                 return null;
 666
 667                         if (bytes.Length == 0)
 668                                 return new byte [0];
 669
 670                         return UrlEncodeToBytes (bytes, 0, bytes.Length);
 671                 }
 672
 673                 static char [] hexChars = "0123456789abcdef".ToCharArray ();
 674                 const string notEncoded = "!'()*-._";
 675
 676                 static void UrlEncodeChar (char c, Stream result, bool isUnicode) {
 677                         if (c > 255) {
 678                                 //FIXME: what happens when there is an internal error?
 679                                 //if (!isUnicode)
 680                                 //      throw new ArgumentOutOfRangeException ("c", c, "c must be less than 256");
 681                                 int idx;
 682                                 int i = (int) c;
 683
 684                                 result.WriteByte ((byte)'%');
 685                                 result.WriteByte ((byte)'u');
 686                                 idx = i >> 12;
 687                                 result.WriteByte ((byte)hexChars [idx]);
 688                                 idx = (i >> 8) & 0x0F;
 689                                 result.WriteByte ((byte)hexChars [idx]);
 690                                 idx = (i >> 4) & 0x0F;
 691                                 result.WriteByte ((byte)hexChars [idx]);
 692                                 idx = i & 0x0F;
 693                                 result.WriteByte ((byte)hexChars [idx]);
 694                                 return;
 695                         }
 696
 697                         if (c>' ' && notEncoded.IndexOf (c)!=-1) {
 698                                 result.WriteByte ((byte)c);
 699                                 return;
 700                         }
 701                         if (c==' ') {
 702                                 result.WriteByte ((byte)'+');
 703                                 return;
 704                         }
 705                         if (    (c < '0') ||
 706                                 (c < 'A' && c > '9') ||
 707                                 (c > 'Z' && c < 'a') ||
 708                                 (c > 'z')) {
 709                                 if (isUnicode && c > 127) {
 710                                         result.WriteByte ((byte)'%');
 711                                         result.WriteByte ((byte)'u');
 712                                         result.WriteByte ((byte)'0');
 713                                         result.WriteByte ((byte)'0');
 714                                 }
 715                                 else
 716                                         result.WriteByte ((byte)'%');
 717
 718                                 int idx = ((int) c) >> 4;
 719                                 result.WriteByte ((byte)hexChars [idx]);
 720                                 idx = ((int) c) & 0x0F;
 721                                 result.WriteByte ((byte)hexChars [idx]);
 722                         }
 723                         else
 724                                 result.WriteByte ((byte)c);
 725                 }
 726
 727                 public static byte [] UrlEncodeToBytes (byte [] bytes, int offset, int count)
 728                 {
 729                         if (bytes == null)
 730                                 return null;
 731
 732                         int len = bytes.Length;
 733                         if (len == 0)
 734                                 return new byte [0];
 735
 736                         if (offset < 0 || offset >= len)
 737                                 throw new ArgumentOutOfRangeException("offset");
 738
 739                         if (count < 0 || count > len - offset)
 740                                 throw new ArgumentOutOfRangeException("count");
 741
 742                         MemoryStream result = new MemoryStream (count);
 743                         int end = offset + count;
 744                         for (int i = offset; i < end; i++)
 745                                 UrlEncodeChar ((char)bytes [i], result, false);
 746
 747                         return result.ToArray();
 748                 }
 749
 750                 public static string UrlEncodeUnicode (string str)
 751                 {
 752                         if (str == null)
 753                                 return null;
 754
 755                         return Encoding.ASCII.GetString (UrlEncodeUnicodeToBytes (str));
 756                 }
 757
 758                 public static byte [] UrlEncodeUnicodeToBytes (string str)
 759                 {
 760                         if (str == null)
 761                                 return null;
 762
 763                         if (str == "")
 764                                 return new byte [0];
 765
 766                         MemoryStream result = new MemoryStream (str.Length);
 767                         foreach (char c in str){
 768                                 UrlEncodeChar (c, result, true);
 769                         }
 770                         return result.ToArray ();
 771                 }
 772
 773                 /// <summary>
 774                 /// Decodes an HTML-encoded string and returns the decoded string.
 775                 /// </summary>
 776                 /// <param name="s">The HTML string to decode. </param>
 777                 /// <returns>The decoded text.</returns>
 778                 public static string HtmlDecode (string s)
 779                 {
 780                         if (s == null)
 781                                 throw new ArgumentNullException ("s");
 782
 783                         if (s.IndexOf ('&') == -1)
 784                                 return s;
 785
 786                         StringBuilder entity = new StringBuilder ();
 787                         StringBuilder output = new StringBuilder ();
 788                         int len = s.Length;
 789                         // 0 -> nothing,
 790                         // 1 -> right after '&'
 791                         // 2 -> between '&' and ';' but no '#'
 792                         // 3 -> '#' found after '&' and getting numbers
 793                         int state = 0;
 794                         int number = 0;
 795                         bool have_trailing_digits = false;
 796
 797                         for (int i = 0; i < len; i++) {
 798                                 char c = s [i];
 799                                 if (state == 0) {
 800                                         if (c == '&') {
 801                                                 entity.Append (c);
 802                                                 state = 1;
 803                                         } else {
 804                                                 output.Append (c);
 805                                         }
 806                                         continue;
 807                                 }
 808
 809                                 if (c == '&') {
 810                                         state = 1;
 811                                         if (have_trailing_digits) {
 812                                                 entity.Append (number.ToString (CultureInfo.InvariantCulture));
 813                                                 have_trailing_digits = false;
 814                                         }
 815
 816                                         output.Append (entity.ToString ());
 817                                         entity.Length = 0;
 818                                         entity.Append ('&');
 819                                         continue;
 820                                 }
 821
 822                                 if (state == 1) {
 823                                         if (c == ';') {
 824                                                 state = 0;
 825                                                 output.Append (entity.ToString ());
 826                                                 output.Append (c);
 827                                                 entity.Length = 0;
 828                                         } else {
 829                                                 number = 0;
 830                                                 if (c != '#') {
 831                                                         state = 2;
 832                                                 } else {
 833                                                         state = 3;
 834                                                 }
 835                                                 entity.Append (c);
 836                                         }
 837                                 } else if (state == 2) {
 838                                         entity.Append (c);
 839                                         if (c == ';') {
 840                                                 string key = entity.ToString ();
 841                                                 if (key.Length > 1 && Entities.ContainsKey (key.Substring (1, key.Length - 2)))
 842                                                         key = Entities [key.Substring (1, key.Length - 2)].ToString ();
 843
 844                                                 output.Append (key);
 845                                                 state = 0;
 846                                                 entity.Length = 0;
 847                                         }
 848                                 } else if (state == 3) {
 849                                         if (c == ';') {
 850                                                 if (number > 65535) {
 851                                                         output.Append ("&#");
 852                                                         output.Append (number.ToString (CultureInfo.InvariantCulture));
 853                                                         output.Append (";");
 854                                                 } else {
 855                                                         output.Append ((char) number);
 856                                                 }
 857                                                 state = 0;
 858                                                 entity.Length = 0;
 859                                                 have_trailing_digits = false;
 860                                         } else if (Char.IsDigit (c)) {
 861                                                 number = number * 10 + ((int) c - '0');
 862                                                 have_trailing_digits = true;
 863                                         } else {
 864                                                 state = 2;
 865                                                 if (have_trailing_digits) {
 866                                                         entity.Append (number.ToString (CultureInfo.InvariantCulture));
 867                                                         have_trailing_digits = false;
 868                                                 }
 869                                                 entity.Append (c);
 870                                         }
 871                                 }
 872                         }
 873
 874                         if (entity.Length > 0) {
 875                                 output.Append (entity.ToString ());
 876                         } else if (have_trailing_digits) {
 877                                 output.Append (number.ToString (CultureInfo.InvariantCulture));
 878                         }
 879                         return output.ToString ();
 880                 }
 881
 882                 /// <summary>
 883                 /// Decodes an HTML-encoded string and sends the resulting output to a TextWriter output stream.
 884                 /// </summary>
 885                 /// <param name="s">The HTML string to decode</param>
 886                 /// <param name="output">The TextWriter output stream containing the decoded string. </param>
 887                 public static void HtmlDecode(string s, TextWriter output)
 888                 {
 889                         if (s != null)
 890                                 output.Write (HtmlDecode (s));
 891                 }
 892
 893                 /// <summary>
 894                 /// HTML-encodes a string and returns the encoded string.
 895                 /// </summary>
 896                 /// <param name="s">The text string to encode. </param>
 897                 /// <returns>The HTML-encoded text.</returns>
 898                 public static string HtmlEncode (string s)
 899                 {
 900                         if (s == null)
 901                                 return null;
 902
 903                         StringBuilder output = new StringBuilder ();
 904
 905                         foreach (char c in s)
 906                                 switch (c) {
 907                                 case '&' :
 908                                         output.Append ("&amp;");
 909                                         break;
 910                                 case '>' :
 911                                         output.Append ("&gt;");
 912                                         break;
 913                                 case '<' :
 914                                         output.Append ("&lt;");
 915                                         break;
 916                                 case '"' :
 917                                         output.Append ("&quot;");
 918                                         break;
 919                                 default:
 920                                         // MS starts encoding with &# from 160 and stops at 255.
 921                                         // We don't do that. One reason is the 65308/65310 unicode
 922                                         // characters that look like '<' and '>'.
 923                                         if (c > 159) {
 924                                                 output.Append ("&#");
 925                                                 output.Append (((int) c).ToString (CultureInfo.InvariantCulture));
 926                                                 output.Append (";");
 927                                         } else {
 928                                                 output.Append (c);
 929                                         }
 930                                         break;
 931                                 }
 932                         return output.ToString ();
 933                 }
 934
 935                 /// <summary>
 936                 /// HTML-encodes a string and sends the resulting output to a TextWriter output stream.
 937                 /// </summary>
 938                 /// <param name="s">The string to encode. </param>
 939                 /// <param name="output">The TextWriter output stream containing the encoded string. </param>
 940                 public static void HtmlEncode(string s, TextWriter output)
 941                 {
 942                         if (s != null)
 943                                 output.Write (HtmlEncode (s));
 944                 }
 945
 946 #if NET_1_1
 947                 public static string UrlPathEncode (string s)
 948                 {
 949                         if (s == null || s.Length == 0)
 950                                 return s;
 951
 952                         MemoryStream result = new MemoryStream ();
 953                         int length = s.Length;
 954             for (int i = 0; i < length; i++) {
 955                                 UrlPathEncodeChar (s [i], result);
 956                         }
 957                         return Encoding.ASCII.GetString (result.ToArray ());
 958                 }
 959
 960                 static void UrlPathEncodeChar (char c, Stream result) {
 961                         if (c > 127) {
 962                                 byte [] bIn = Encoding.UTF8.GetBytes (c.ToString ());
 963                                 for (int i = 0; i < bIn.Length; i++) {
 964                                         result.WriteByte ((byte) '%');
 965                                         int idx = ((int) bIn [i]) >> 4;
 966                                         result.WriteByte ((byte) hexChars [idx]);
 967                                         idx = ((int) bIn [i]) & 0x0F;
 968                                         result.WriteByte ((byte) hexChars [idx]);
 969                                 }
 970                         }
 971                         else if (c == ' ') {
 972                                 result.WriteByte ((byte) '%');
 973                                 result.WriteByte ((byte) '2');
 974                                 result.WriteByte ((byte) '0');
 975                         }
 976                         else
 977                                 result.WriteByte ((byte) c);
 978                 }
 979 #endif
 980
 981 #if NET_2_0
 982                 public static NameValueCollection ParseQueryString (string query)
 983                 {
 984                         return ParseQueryString (query, Encoding.UTF8);
 985                 }
 986
 987                 public static NameValueCollection ParseQueryString (string query, Encoding encoding)
 988                 {
 989                         if (query == null)
 990                                 throw new ArgumentNullException ("query");
 991                         if (encoding == null)
 992                                 throw new ArgumentNullException ("encoding");
 993                         if (query.Length == 0 || (query.Length == 1 && query[0] == '?'))
 994                                 return new NameValueCollection ();
 995                         if (query[0] == '?')
 996                                 query = query.Substring (1);
 997
 998                         NameValueCollection result = new NameValueCollection ();
 999                         ParseQueryString (query, encoding, result);
1000                         return result;
1001                 }
1002 #endif
1003
1004                 internal static void ParseQueryString (string query, Encoding encoding, NameValueCollection result)
1005                 {
1006                         if (query.Length == 0)
1007                                 return;
1008
1009                         int namePos = 0;
1010                         while (namePos <= query.Length) {
1011                                 int valuePos = -1, valueEnd = -1;
1012                                 for (int q = namePos; q < query.Length; q++) {
1013                                         if (valuePos == -1 && query[q] == '=') {
1014                                                 valuePos = q + 1;
1015                                         } else if (query[q] == '&') {
1016                                                 valueEnd = q;
1017                                                 break;
1018                                         }
1019                                 }
1020
1021                                 string name, value;
1022                                 if (valuePos == -1) {
1023                                         name = null;
1024                                         valuePos = namePos;
1025                                 } else {
1026                                         name = UrlDecode (query.Substring (namePos, valuePos - namePos - 1), encoding);
1027                                 }
1028                                 if (valueEnd < 0) {
1029                                         namePos = -1;
1030                                         valueEnd = query.Length;
1031                                 } else {
1032                                         namePos = valueEnd + 1;
1033                                 }
1034                                 value = UrlDecode (query.Substring (valuePos, valueEnd - valuePos), encoding);
1035
1036                                 result.Add (name, value);
1037                                 if (namePos == -1) break;
1038                         }
1039                 }
1040                 #endregion // Methods
1041         }
1042 }
1043