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 #if NET_2_0
  46                 internal const char QueryParamSeparator = ';';
  47 #else
  48                 internal const char QueryParamSeparator = '&';
  49 #endif
  50                 #region Fields
  51
  52                 static Hashtable entities;
  53                 static object lock_ = new object ();
  54
  55                 #endregion // Fields
  56
  57                 static Hashtable Entities {
  58                         get {
  59                                 lock (lock_) {
  60                                         if (entities == null)
  61                                                 InitEntities ();
  62
  63                                         return entities;
  64                                 }
  65                         }
  66                 }
  67
  68                 #region Constructors
  69
  70                 static void InitEntities ()
  71                 {
  72                         // Build the hash table of HTML entity references.  This list comes
  73                         // from the HTML 4.01 W3C recommendation.
  74                         entities = new Hashtable ();
  75                         entities.Add ("nbsp", '\u00A0');
  76                         entities.Add ("iexcl", '\u00A1');
  77                         entities.Add ("cent", '\u00A2');
  78                         entities.Add ("pound", '\u00A3');
  79                         entities.Add ("curren", '\u00A4');
  80                         entities.Add ("yen", '\u00A5');
  81                         entities.Add ("brvbar", '\u00A6');
  82                         entities.Add ("sect", '\u00A7');
  83                         entities.Add ("uml", '\u00A8');
  84                         entities.Add ("copy", '\u00A9');
  85                         entities.Add ("ordf", '\u00AA');
  86                         entities.Add ("laquo", '\u00AB');
  87                         entities.Add ("not", '\u00AC');
  88                         entities.Add ("shy", '\u00AD');
  89                         entities.Add ("reg", '\u00AE');
  90                         entities.Add ("macr", '\u00AF');
  91                         entities.Add ("deg", '\u00B0');
  92                         entities.Add ("plusmn", '\u00B1');
  93                         entities.Add ("sup2", '\u00B2');
  94                         entities.Add ("sup3", '\u00B3');
  95                         entities.Add ("acute", '\u00B4');
  96                         entities.Add ("micro", '\u00B5');
  97                         entities.Add ("para", '\u00B6');
  98                         entities.Add ("middot", '\u00B7');
  99                         entities.Add ("cedil", '\u00B8');
 100                         entities.Add ("sup1", '\u00B9');
 101                         entities.Add ("ordm", '\u00BA');
 102                         entities.Add ("raquo", '\u00BB');
 103                         entities.Add ("frac14", '\u00BC');
 104                         entities.Add ("frac12", '\u00BD');
 105                         entities.Add ("frac34", '\u00BE');
 106                         entities.Add ("iquest", '\u00BF');
 107                         entities.Add ("Agrave", '\u00C0');
 108                         entities.Add ("Aacute", '\u00C1');
 109                         entities.Add ("Acirc", '\u00C2');
 110                         entities.Add ("Atilde", '\u00C3');
 111                         entities.Add ("Auml", '\u00C4');
 112                         entities.Add ("Aring", '\u00C5');
 113                         entities.Add ("AElig", '\u00C6');
 114                         entities.Add ("Ccedil", '\u00C7');
 115                         entities.Add ("Egrave", '\u00C8');
 116                         entities.Add ("Eacute", '\u00C9');
 117                         entities.Add ("Ecirc", '\u00CA');
 118                         entities.Add ("Euml", '\u00CB');
 119                         entities.Add ("Igrave", '\u00CC');
 120                         entities.Add ("Iacute", '\u00CD');
 121                         entities.Add ("Icirc", '\u00CE');
 122                         entities.Add ("Iuml", '\u00CF');
 123                         entities.Add ("ETH", '\u00D0');
 124                         entities.Add ("Ntilde", '\u00D1');
 125                         entities.Add ("Ograve", '\u00D2');
 126                         entities.Add ("Oacute", '\u00D3');
 127                         entities.Add ("Ocirc", '\u00D4');
 128                         entities.Add ("Otilde", '\u00D5');
 129                         entities.Add ("Ouml", '\u00D6');
 130                         entities.Add ("times", '\u00D7');
 131                         entities.Add ("Oslash", '\u00D8');
 132                         entities.Add ("Ugrave", '\u00D9');
 133                         entities.Add ("Uacute", '\u00DA');
 134                         entities.Add ("Ucirc", '\u00DB');
 135                         entities.Add ("Uuml", '\u00DC');
 136                         entities.Add ("Yacute", '\u00DD');
 137                         entities.Add ("THORN", '\u00DE');
 138                         entities.Add ("szlig", '\u00DF');
 139                         entities.Add ("agrave", '\u00E0');
 140                         entities.Add ("aacute", '\u00E1');
 141                         entities.Add ("acirc", '\u00E2');
 142                         entities.Add ("atilde", '\u00E3');
 143                         entities.Add ("auml", '\u00E4');
 144                         entities.Add ("aring", '\u00E5');
 145                         entities.Add ("aelig", '\u00E6');
 146                         entities.Add ("ccedil", '\u00E7');
 147                         entities.Add ("egrave", '\u00E8');
 148                         entities.Add ("eacute", '\u00E9');
 149                         entities.Add ("ecirc", '\u00EA');
 150                         entities.Add ("euml", '\u00EB');
 151                         entities.Add ("igrave", '\u00EC');
 152                         entities.Add ("iacute", '\u00ED');
 153                         entities.Add ("icirc", '\u00EE');
 154                         entities.Add ("iuml", '\u00EF');
 155                         entities.Add ("eth", '\u00F0');
 156                         entities.Add ("ntilde", '\u00F1');
 157                         entities.Add ("ograve", '\u00F2');
 158                         entities.Add ("oacute", '\u00F3');
 159                         entities.Add ("ocirc", '\u00F4');
 160                         entities.Add ("otilde", '\u00F5');
 161                         entities.Add ("ouml", '\u00F6');
 162                         entities.Add ("divide", '\u00F7');
 163                         entities.Add ("oslash", '\u00F8');
 164                         entities.Add ("ugrave", '\u00F9');
 165                         entities.Add ("uacute", '\u00FA');
 166                         entities.Add ("ucirc", '\u00FB');
 167                         entities.Add ("uuml", '\u00FC');
 168                         entities.Add ("yacute", '\u00FD');
 169                         entities.Add ("thorn", '\u00FE');
 170                         entities.Add ("yuml", '\u00FF');
 171                         entities.Add ("fnof", '\u0192');
 172                         entities.Add ("Alpha", '\u0391');
 173                         entities.Add ("Beta", '\u0392');
 174                         entities.Add ("Gamma", '\u0393');
 175                         entities.Add ("Delta", '\u0394');
 176                         entities.Add ("Epsilon", '\u0395');
 177                         entities.Add ("Zeta", '\u0396');
 178                         entities.Add ("Eta", '\u0397');
 179                         entities.Add ("Theta", '\u0398');
 180                         entities.Add ("Iota", '\u0399');
 181                         entities.Add ("Kappa", '\u039A');
 182                         entities.Add ("Lambda", '\u039B');
 183                         entities.Add ("Mu", '\u039C');
 184                         entities.Add ("Nu", '\u039D');
 185                         entities.Add ("Xi", '\u039E');
 186                         entities.Add ("Omicron", '\u039F');
 187                         entities.Add ("Pi", '\u03A0');
 188                         entities.Add ("Rho", '\u03A1');
 189                         entities.Add ("Sigma", '\u03A3');
 190                         entities.Add ("Tau", '\u03A4');
 191                         entities.Add ("Upsilon", '\u03A5');
 192                         entities.Add ("Phi", '\u03A6');
 193                         entities.Add ("Chi", '\u03A7');
 194                         entities.Add ("Psi", '\u03A8');
 195                         entities.Add ("Omega", '\u03A9');
 196                         entities.Add ("alpha", '\u03B1');
 197                         entities.Add ("beta", '\u03B2');
 198                         entities.Add ("gamma", '\u03B3');
 199                         entities.Add ("delta", '\u03B4');
 200                         entities.Add ("epsilon", '\u03B5');
 201                         entities.Add ("zeta", '\u03B6');
 202                         entities.Add ("eta", '\u03B7');
 203                         entities.Add ("theta", '\u03B8');
 204                         entities.Add ("iota", '\u03B9');
 205                         entities.Add ("kappa", '\u03BA');
 206                         entities.Add ("lambda", '\u03BB');
 207                         entities.Add ("mu", '\u03BC');
 208                         entities.Add ("nu", '\u03BD');
 209                         entities.Add ("xi", '\u03BE');
 210                         entities.Add ("omicron", '\u03BF');
 211                         entities.Add ("pi", '\u03C0');
 212                         entities.Add ("rho", '\u03C1');
 213                         entities.Add ("sigmaf", '\u03C2');
 214                         entities.Add ("sigma", '\u03C3');
 215                         entities.Add ("tau", '\u03C4');
 216                         entities.Add ("upsilon", '\u03C5');
 217                         entities.Add ("phi", '\u03C6');
 218                         entities.Add ("chi", '\u03C7');
 219                         entities.Add ("psi", '\u03C8');
 220                         entities.Add ("omega", '\u03C9');
 221                         entities.Add ("thetasym", '\u03D1');
 222                         entities.Add ("upsih", '\u03D2');
 223                         entities.Add ("piv", '\u03D6');
 224                         entities.Add ("bull", '\u2022');
 225                         entities.Add ("hellip", '\u2026');
 226                         entities.Add ("prime", '\u2032');
 227                         entities.Add ("Prime", '\u2033');
 228                         entities.Add ("oline", '\u203E');
 229                         entities.Add ("frasl", '\u2044');
 230                         entities.Add ("weierp", '\u2118');
 231                         entities.Add ("image", '\u2111');
 232                         entities.Add ("real", '\u211C');
 233                         entities.Add ("trade", '\u2122');
 234                         entities.Add ("alefsym", '\u2135');
 235                         entities.Add ("larr", '\u2190');
 236                         entities.Add ("uarr", '\u2191');
 237                         entities.Add ("rarr", '\u2192');
 238                         entities.Add ("darr", '\u2193');
 239                         entities.Add ("harr", '\u2194');
 240                         entities.Add ("crarr", '\u21B5');
 241                         entities.Add ("lArr", '\u21D0');
 242                         entities.Add ("uArr", '\u21D1');
 243                         entities.Add ("rArr", '\u21D2');
 244                         entities.Add ("dArr", '\u21D3');
 245                         entities.Add ("hArr", '\u21D4');
 246                         entities.Add ("forall", '\u2200');
 247                         entities.Add ("part", '\u2202');
 248                         entities.Add ("exist", '\u2203');
 249                         entities.Add ("empty", '\u2205');
 250                         entities.Add ("nabla", '\u2207');
 251                         entities.Add ("isin", '\u2208');
 252                         entities.Add ("notin", '\u2209');
 253                         entities.Add ("ni", '\u220B');
 254                         entities.Add ("prod", '\u220F');
 255                         entities.Add ("sum", '\u2211');
 256                         entities.Add ("minus", '\u2212');
 257                         entities.Add ("lowast", '\u2217');
 258                         entities.Add ("radic", '\u221A');
 259                         entities.Add ("prop", '\u221D');
 260                         entities.Add ("infin", '\u221E');
 261                         entities.Add ("ang", '\u2220');
 262                         entities.Add ("and", '\u2227');
 263                         entities.Add ("or", '\u2228');
 264                         entities.Add ("cap", '\u2229');
 265                         entities.Add ("cup", '\u222A');
 266                         entities.Add ("int", '\u222B');
 267                         entities.Add ("there4", '\u2234');
 268                         entities.Add ("sim", '\u223C');
 269                         entities.Add ("cong", '\u2245');
 270                         entities.Add ("asymp", '\u2248');
 271                         entities.Add ("ne", '\u2260');
 272                         entities.Add ("equiv", '\u2261');
 273                         entities.Add ("le", '\u2264');
 274                         entities.Add ("ge", '\u2265');
 275                         entities.Add ("sub", '\u2282');
 276                         entities.Add ("sup", '\u2283');
 277                         entities.Add ("nsub", '\u2284');
 278                         entities.Add ("sube", '\u2286');
 279                         entities.Add ("supe", '\u2287');
 280                         entities.Add ("oplus", '\u2295');
 281                         entities.Add ("otimes", '\u2297');
 282                         entities.Add ("perp", '\u22A5');
 283                         entities.Add ("sdot", '\u22C5');
 284                         entities.Add ("lceil", '\u2308');
 285                         entities.Add ("rceil", '\u2309');
 286                         entities.Add ("lfloor", '\u230A');
 287                         entities.Add ("rfloor", '\u230B');
 288                         entities.Add ("lang", '\u2329');
 289                         entities.Add ("rang", '\u232A');
 290                         entities.Add ("loz", '\u25CA');
 291                         entities.Add ("spades", '\u2660');
 292                         entities.Add ("clubs", '\u2663');
 293                         entities.Add ("hearts", '\u2665');
 294                         entities.Add ("diams", '\u2666');
 295                         entities.Add ("quot", '\u0022');
 296                         entities.Add ("amp", '\u0026');
 297                         entities.Add ("lt", '\u003C');
 298                         entities.Add ("gt", '\u003E');
 299                         entities.Add ("OElig", '\u0152');
 300                         entities.Add ("oelig", '\u0153');
 301                         entities.Add ("Scaron", '\u0160');
 302                         entities.Add ("scaron", '\u0161');
 303                         entities.Add ("Yuml", '\u0178');
 304                         entities.Add ("circ", '\u02C6');
 305                         entities.Add ("tilde", '\u02DC');
 306                         entities.Add ("ensp", '\u2002');
 307                         entities.Add ("emsp", '\u2003');
 308                         entities.Add ("thinsp", '\u2009');
 309                         entities.Add ("zwnj", '\u200C');
 310                         entities.Add ("zwj", '\u200D');
 311                         entities.Add ("lrm", '\u200E');
 312                         entities.Add ("rlm", '\u200F');
 313                         entities.Add ("ndash", '\u2013');
 314                         entities.Add ("mdash", '\u2014');
 315                         entities.Add ("lsquo", '\u2018');
 316                         entities.Add ("rsquo", '\u2019');
 317                         entities.Add ("sbquo", '\u201A');
 318                         entities.Add ("ldquo", '\u201C');
 319                         entities.Add ("rdquo", '\u201D');
 320                         entities.Add ("bdquo", '\u201E');
 321                         entities.Add ("dagger", '\u2020');
 322                         entities.Add ("Dagger", '\u2021');
 323                         entities.Add ("permil", '\u2030');
 324                         entities.Add ("lsaquo", '\u2039');
 325                         entities.Add ("rsaquo", '\u203A');
 326                         entities.Add ("euro", '\u20AC');
 327                 }
 328
 329                 public HttpUtility ()
 330                 {
 331                 }
 332
 333                 #endregion // Constructors
 334
 335                 #region Methods
 336
 337                 public static void HtmlAttributeEncode (string s, TextWriter output)
 338                 {
 339                         output.Write(HtmlAttributeEncode(s));
 340                 }
 341
 342                 public static string HtmlAttributeEncode (string s)
 343                 {
 344                         if (null == s)
 345                                 return null;
 346
 347                         if (s.IndexOf ('&') == -1 && s.IndexOf ('"') == -1 && s.IndexOf ('<') == -1)
 348                                 return s;
 349
 350                         StringBuilder output = new StringBuilder ();
 351                         foreach (char c in s)
 352                                 switch (c) {
 353                                 case '&' :
 354                                         output.Append ("&amp;");
 355                                         break;
 356                                 case '"' :
 357                                         output.Append ("&quot;");
 358                                         break;
 359                                 case '<':
 360                                         output.Append ("&lt;");
 361                                         break;
 362                                 default:
 363                                         output.Append (c);
 364                                         break;
 365                                 }
 366
 367                         return output.ToString();
 368                 }
 369
 370                 public static string UrlDecode (string str)
 371                 {
 372                         return UrlDecode(str, Encoding.UTF8);
 373                 }
 374
 375                 private static char [] GetChars (MemoryStream b, Encoding e)
 376                 {
 377                         return e.GetChars (b.GetBuffer (), 0, (int) b.Length);
 378                 }
 379
 380                 public static string UrlDecode (string s, Encoding e)
 381                 {
 382                         if (null == s)
 383                                 return null;
 384
 385                         if (s.IndexOf ('%') == -1 && s.IndexOf ('+') == -1)
 386                                 return s;
 387
 388                         if (e == null)
 389                                 e = Encoding.UTF8;
 390
 391                         StringBuilder output = new StringBuilder ();
 392                         long len = s.Length;
 393                         MemoryStream bytes = new MemoryStream ();
 394                         int xchar;
 395
 396                         for (int i = 0; i < len; i++) {
 397                                 if (s [i] == '%' && i + 2 < len && s [i + 1] != '%') {
 398                                         if (s [i + 1] == 'u' && i + 5 < len) {
 399                                                 if (bytes.Length > 0) {
 400                                                         output.Append (GetChars (bytes, e));
 401                                                         bytes.SetLength (0);
 402                                                 }
 403
 404                                                 xchar = GetChar (s, i + 2, 4);
 405                                                 if (xchar != -1) {
 406                                                         output.Append ((char) xchar);
 407                                                         i += 5;
 408                                                 } else {
 409                                                         output.Append ('%');
 410                                                 }
 411                                         } else if ((xchar = GetChar (s, i + 1, 2)) != -1) {
 412                                                 bytes.WriteByte ((byte) xchar);
 413                                                 i += 2;
 414                                         } else {
 415                                                 output.Append ('%');
 416                                         }
 417                                         continue;
 418                                 }
 419
 420                                 if (bytes.Length > 0) {
 421                                         output.Append (GetChars (bytes, e));
 422                                         bytes.SetLength (0);
 423                                 }
 424
 425                                 if (s [i] == '+') {
 426                                         output.Append (' ');
 427                                 } else {
 428                                         output.Append (s [i]);
 429                                 }
 430                         }
 431
 432                         if (bytes.Length > 0) {
 433                                 output.Append (GetChars (bytes, e));
 434                         }
 435
 436                         bytes = null;
 437                         return output.ToString ();
 438                 }
 439
 440                 public static string UrlDecode (byte [] bytes, Encoding e)
 441                 {
 442                         if (bytes == null)
 443                                 return null;
 444
 445                         return UrlDecode (bytes, 0, bytes.Length, e);
 446                 }
 447
 448                 private static int GetInt (byte b)
 449                 {
 450                         char c = (char) b;
 451                         if (c >= '0' && c <= '9')
 452                                 return c - '0';
 453
 454                         if (c >= 'a' && c <= 'f')
 455                                 return c - 'a' + 10;
 456
 457                         if (c >= 'A' && c <= 'F')
 458                                 return c - 'A' + 10;
 459
 460                         return -1;
 461                 }
 462
 463                 private static int GetChar (byte [] bytes, int offset, int length)
 464                 {
 465                         int value = 0;
 466                         int end = length + offset;
 467                         for (int i = offset; i < end; i++) {
 468                                 int current = GetInt (bytes [i]);
 469                                 if (current == -1)
 470                                         return -1;
 471                                 value = (value << 4) + current;
 472                         }
 473
 474                         return value;
 475                 }
 476
 477                 private static int GetChar (string str, int offset, int length)
 478                 {
 479                         int val = 0;
 480                         int end = length + offset;
 481                         for (int i = offset; i < end; i++) {
 482                                 char c = str [i];
 483                                 if (c > 127)
 484                                         return -1;
 485
 486                                 int current = GetInt ((byte) c);
 487                                 if (current == -1)
 488                                         return -1;
 489                                 val = (val << 4) + current;
 490                         }
 491
 492                         return val;
 493                 }
 494
 495                 public static string UrlDecode (byte [] bytes, int offset, int count, Encoding e)
 496                 {
 497                         if (bytes == null)
 498                                 return null;
 499                         if (count == 0)
 500                                 return String.Empty;
 501
 502                         if (bytes == null)
 503                                 throw new ArgumentNullException ("bytes");
 504
 505                         if (offset < 0 || offset > bytes.Length)
 506                                 throw new ArgumentOutOfRangeException ("offset");
 507
 508                         if (count < 0 || offset + count > bytes.Length)
 509                                 throw new ArgumentOutOfRangeException ("count");
 510
 511                         StringBuilder output = new StringBuilder ();
 512                         MemoryStream acc = new MemoryStream ();
 513
 514                         int end = count + offset;
 515                         int xchar;
 516                         for (int i = offset; i < end; i++) {
 517                                 if (bytes [i] == '%' && i + 2 < count && bytes [i + 1] != '%') {
 518                                         if (bytes [i + 1] == (byte) 'u' && i + 5 < end) {
 519                                                 if (acc.Length > 0) {
 520                                                         output.Append (GetChars (acc, e));
 521                                                         acc.SetLength (0);
 522                                                 }
 523                                                 xchar = GetChar (bytes, i + 2, 4);
 524                                                 if (xchar != -1) {
 525                                                         output.Append ((char) xchar);
 526                                                         i += 5;
 527                                                         continue;
 528                                                 }
 529                                         } else if ((xchar = GetChar (bytes, i + 1, 2)) != -1) {
 530                                                 acc.WriteByte ((byte) xchar);
 531                                                 i += 2;
 532                                                 continue;
 533                                         }
 534                                 }
 535
 536                                 if (acc.Length > 0) {
 537                                         output.Append (GetChars (acc, e));
 538                                         acc.SetLength (0);
 539                                 }
 540
 541                                 if (bytes [i] == '+') {
 542                                         output.Append (' ');
 543                                 } else {
 544                                         output.Append ((char) bytes [i]);
 545                                 }
 546                         }
 547
 548                         if (acc.Length > 0) {
 549                                 output.Append (GetChars (acc, e));
 550                         }
 551
 552                         acc = null;
 553                         return output.ToString ();
 554                 }
 555
 556                 public static byte [] UrlDecodeToBytes (byte [] bytes)
 557                 {
 558                         if (bytes == null)
 559                                 return null;
 560
 561                         return UrlDecodeToBytes (bytes, 0, bytes.Length);
 562                 }
 563
 564                 public static byte [] UrlDecodeToBytes (string str)
 565                 {
 566                         return UrlDecodeToBytes (str, Encoding.UTF8);
 567                 }
 568
 569                 public static byte [] UrlDecodeToBytes (string str, Encoding e)
 570                 {
 571                         if (str == null)
 572                                 return null;
 573
 574                         if (e == null)
 575                                 throw new ArgumentNullException ("e");
 576
 577                         return UrlDecodeToBytes (e.GetBytes (str));
 578                 }
 579
 580                 public static byte [] UrlDecodeToBytes (byte [] bytes, int offset, int count)
 581                 {
 582                         if (bytes == null)
 583                                 return null;
 584                         if (count == 0)
 585                                 return new byte [0];
 586
 587                         int len = bytes.Length;
 588                         if (offset < 0 || offset >= len)
 589                                 throw new ArgumentOutOfRangeException("offset");
 590
 591                         if (count < 0 || offset > len - count)
 592                                 throw new ArgumentOutOfRangeException("count");
 593
 594                         MemoryStream result = new MemoryStream ();
 595                         int end = offset + count;
 596                         for (int i = offset; i < end; i++){
 597                                 char c = (char) bytes [i];
 598                                 if (c == '+') {
 599                                         c = ' ';
 600                                 } else if (c == '%' && i < end - 2) {
 601                                         int xchar = GetChar (bytes, i + 1, 2);
 602                                         if (xchar != -1) {
 603                                                 c = (char) xchar;
 604                                                 i += 2;
 605                                         }
 606                                 }
 607                                 result.WriteByte ((byte) c);
 608                         }
 609
 610                         return result.ToArray ();
 611                 }
 612
 613                 public static string UrlEncode(string str)
 614                 {
 615                         return UrlEncode(str, Encoding.UTF8);
 616                 }
 617
 618                 public static string UrlEncode (string s, Encoding Enc)
 619                 {
 620                         if (s == null)
 621                                 return null;
 622
 623                         if (s == "")
 624                                 return "";
 625
 626                         byte [] bytes = Enc.GetBytes (s);
 627                         return Encoding.ASCII.GetString (UrlEncodeToBytes (bytes, 0, bytes.Length));
 628                 }
 629
 630                 public static string UrlEncode (byte [] bytes)
 631                 {
 632                         if (bytes == null)
 633                                 return null;
 634
 635                         if (bytes.Length == 0)
 636                                 return "";
 637
 638                         return Encoding.ASCII.GetString (UrlEncodeToBytes (bytes, 0, bytes.Length));
 639                 }
 640
 641                 public static string UrlEncode (byte [] bytes, int offset, int count)
 642                 {
 643                         if (bytes == null)
 644                                 return null;
 645
 646                         if (bytes.Length == 0)
 647                                 return "";
 648
 649                         return Encoding.ASCII.GetString (UrlEncodeToBytes (bytes, offset, count));
 650                 }
 651
 652                 public static byte [] UrlEncodeToBytes (string str)
 653                 {
 654                         return UrlEncodeToBytes (str, Encoding.UTF8);
 655                 }
 656
 657                 public static byte [] UrlEncodeToBytes (string str, Encoding e)
 658                 {
 659                         if (str == null)
 660                                 return null;
 661
 662                         if (str == "")
 663                                 return new byte [0];
 664
 665                         byte [] bytes = e.GetBytes (str);
 666                         return UrlEncodeToBytes (bytes, 0, bytes.Length);
 667                 }
 668
 669                 public static byte [] UrlEncodeToBytes (byte [] bytes)
 670                 {
 671                         if (bytes == null)
 672                                 return null;
 673
 674                         if (bytes.Length == 0)
 675                                 return new byte [0];
 676
 677                         return UrlEncodeToBytes (bytes, 0, bytes.Length);
 678                 }
 679
 680                 static char [] hexChars = "0123456789abcdef".ToCharArray ();
 681                 const string notEncoded = "!'()*-._";
 682
 683                 static void UrlEncodeChar (char c, Stream result, bool isUnicode) {
 684                         if (c > 255) {
 685                                 //FIXME: what happens when there is an internal error?
 686                                 //if (!isUnicode)
 687                                 //      throw new ArgumentOutOfRangeException ("c", c, "c must be less than 256");
 688                                 int idx;
 689                                 int i = (int) c;
 690
 691                                 result.WriteByte ((byte)'%');
 692                                 result.WriteByte ((byte)'u');
 693                                 idx = i >> 12;
 694                                 result.WriteByte ((byte)hexChars [idx]);
 695                                 idx = (i >> 8) & 0x0F;
 696                                 result.WriteByte ((byte)hexChars [idx]);
 697                                 idx = (i >> 4) & 0x0F;
 698                                 result.WriteByte ((byte)hexChars [idx]);
 699                                 idx = i & 0x0F;
 700                                 result.WriteByte ((byte)hexChars [idx]);
 701                                 return;
 702                         }
 703
 704                         if (c>' ' && notEncoded.IndexOf (c)!=-1) {
 705                                 result.WriteByte ((byte)c);
 706                                 return;
 707                         }
 708                         if (c==' ') {
 709                                 result.WriteByte ((byte)'+');
 710                                 return;
 711                         }
 712                         if (    (c < '0') ||
 713                                 (c < 'A' && c > '9') ||
 714                                 (c > 'Z' && c < 'a') ||
 715                                 (c > 'z')) {
 716                                 if (isUnicode && c > 127) {
 717                                         result.WriteByte ((byte)'%');
 718                                         result.WriteByte ((byte)'u');
 719                                         result.WriteByte ((byte)'0');
 720                                         result.WriteByte ((byte)'0');
 721                                 }
 722                                 else
 723                                         result.WriteByte ((byte)'%');
 724
 725                                 int idx = ((int) c) >> 4;
 726                                 result.WriteByte ((byte)hexChars [idx]);
 727                                 idx = ((int) c) & 0x0F;
 728                                 result.WriteByte ((byte)hexChars [idx]);
 729                         }
 730                         else
 731                                 result.WriteByte ((byte)c);
 732                 }
 733
 734                 public static byte [] UrlEncodeToBytes (byte [] bytes, int offset, int count)
 735                 {
 736                         if (bytes == null)
 737                                 return null;
 738
 739                         int len = bytes.Length;
 740                         if (len == 0)
 741                                 return new byte [0];
 742
 743                         if (offset < 0 || offset >= len)
 744                                 throw new ArgumentOutOfRangeException("offset");
 745
 746                         if (count < 0 || count > len - offset)
 747                                 throw new ArgumentOutOfRangeException("count");
 748
 749                         MemoryStream result = new MemoryStream (count);
 750                         int end = offset + count;
 751                         for (int i = offset; i < end; i++)
 752                                 UrlEncodeChar ((char)bytes [i], result, false);
 753
 754                         return result.ToArray();
 755                 }
 756
 757                 public static string UrlEncodeUnicode (string str)
 758                 {
 759                         if (str == null)
 760                                 return null;
 761
 762                         return Encoding.ASCII.GetString (UrlEncodeUnicodeToBytes (str));
 763                 }
 764
 765                 public static byte [] UrlEncodeUnicodeToBytes (string str)
 766                 {
 767                         if (str == null)
 768                                 return null;
 769
 770                         if (str == "")
 771                                 return new byte [0];
 772
 773                         MemoryStream result = new MemoryStream (str.Length);
 774                         foreach (char c in str){
 775                                 UrlEncodeChar (c, result, true);
 776                         }
 777                         return result.ToArray ();
 778                 }
 779
 780                 /// <summary>
 781                 /// Decodes an HTML-encoded string and returns the decoded string.
 782                 /// </summary>
 783                 /// <param name="s">The HTML string to decode. </param>
 784                 /// <returns>The decoded text.</returns>
 785                 public static string HtmlDecode (string s)
 786                 {
 787                         if (s == null)
 788                                 throw new ArgumentNullException ("s");
 789
 790                         if (s.IndexOf ('&') == -1)
 791                                 return s;
 792
 793                         StringBuilder entity = new StringBuilder ();
 794                         StringBuilder output = new StringBuilder ();
 795                         int len = s.Length;
 796                         // 0 -> nothing,
 797                         // 1 -> right after '&'
 798                         // 2 -> between '&' and ';' but no '#'
 799                         // 3 -> '#' found after '&' and getting numbers
 800                         int state = 0;
 801                         int number = 0;
 802                         bool have_trailing_digits = false;
 803
 804                         for (int i = 0; i < len; i++) {
 805                                 char c = s [i];
 806                                 if (state == 0) {
 807                                         if (c == '&') {
 808                                                 entity.Append (c);
 809                                                 state = 1;
 810                                         } else {
 811                                                 output.Append (c);
 812                                         }
 813                                         continue;
 814                                 }
 815
 816                                 if (c == '&') {
 817                                         state = 1;
 818                                         if (have_trailing_digits) {
 819                                                 entity.Append (number.ToString (CultureInfo.InvariantCulture));
 820                                                 have_trailing_digits = false;
 821                                         }
 822
 823                                         output.Append (entity.ToString ());
 824                                         entity.Length = 0;
 825                                         entity.Append ('&');
 826                                         continue;
 827                                 }
 828
 829                                 if (state == 1) {
 830                                         if (c == ';') {
 831                                                 state = 0;
 832                                                 output.Append (entity.ToString ());
 833                                                 output.Append (c);
 834                                                 entity.Length = 0;
 835                                         } else {
 836                                                 number = 0;
 837                                                 if (c != '#') {
 838                                                         state = 2;
 839                                                 } else {
 840                                                         state = 3;
 841                                                 }
 842                                                 entity.Append (c);
 843                                         }
 844                                 } else if (state == 2) {
 845                                         entity.Append (c);
 846                                         if (c == ';') {
 847                                                 string key = entity.ToString ();
 848                                                 if (key.Length > 1 && Entities.ContainsKey (key.Substring (1, key.Length - 2)))
 849                                                         key = Entities [key.Substring (1, key.Length - 2)].ToString ();
 850
 851                                                 output.Append (key);
 852                                                 state = 0;
 853                                                 entity.Length = 0;
 854                                         }
 855                                 } else if (state == 3) {
 856                                         if (c == ';') {
 857                                                 if (number > 65535) {
 858                                                         output.Append ("&#");
 859                                                         output.Append (number.ToString (CultureInfo.InvariantCulture));
 860                                                         output.Append (";");
 861                                                 } else {
 862                                                         output.Append ((char) number);
 863                                                 }
 864                                                 state = 0;
 865                                                 entity.Length = 0;
 866                                                 have_trailing_digits = false;
 867                                         } else if (Char.IsDigit (c)) {
 868                                                 number = number * 10 + ((int) c - '0');
 869                                                 have_trailing_digits = true;
 870                                         } else {
 871                                                 state = 2;
 872                                                 if (have_trailing_digits) {
 873                                                         entity.Append (number.ToString (CultureInfo.InvariantCulture));
 874                                                         have_trailing_digits = false;
 875                                                 }
 876                                                 entity.Append (c);
 877                                         }
 878                                 }
 879                         }
 880
 881                         if (entity.Length > 0) {
 882                                 output.Append (entity.ToString ());
 883                         } else if (have_trailing_digits) {
 884                                 output.Append (number.ToString (CultureInfo.InvariantCulture));
 885                         }
 886                         return output.ToString ();
 887                 }
 888
 889                 /// <summary>
 890                 /// Decodes an HTML-encoded string and sends the resulting output to a TextWriter output stream.
 891                 /// </summary>
 892                 /// <param name="s">The HTML string to decode</param>
 893                 /// <param name="output">The TextWriter output stream containing the decoded string. </param>
 894                 public static void HtmlDecode(string s, TextWriter output)
 895                 {
 896                         if (s != null)
 897                                 output.Write (HtmlDecode (s));
 898                 }
 899
 900                 /// <summary>
 901                 /// HTML-encodes a string and returns the encoded string.
 902                 /// </summary>
 903                 /// <param name="s">The text string to encode. </param>
 904                 /// <returns>The HTML-encoded text.</returns>
 905                 public static string HtmlEncode (string s)
 906                 {
 907                         if (s == null)
 908                                 return null;
 909
 910                         StringBuilder output = new StringBuilder ();
 911
 912                         foreach (char c in s)
 913                                 switch (c) {
 914                                 case '&' :
 915                                         output.Append ("&amp;");
 916                                         break;
 917                                 case '>' :
 918                                         output.Append ("&gt;");
 919                                         break;
 920                                 case '<' :
 921                                         output.Append ("&lt;");
 922                                         break;
 923                                 case '"' :
 924                                         output.Append ("&quot;");
 925                                         break;
 926                                 default:
 927                                         // MS starts encoding with &# from 160 and stops at 255.
 928                                         // We don't do that. One reason is the 65308/65310 unicode
 929                                         // characters that look like '<' and '>'.
 930                                         if (c > 159) {
 931                                                 output.Append ("&#");
 932                                                 output.Append (((int) c).ToString (CultureInfo.InvariantCulture));
 933                                                 output.Append (";");
 934                                         } else {
 935                                                 output.Append (c);
 936                                         }
 937                                         break;
 938                                 }
 939                         return output.ToString ();
 940                 }
 941
 942                 /// <summary>
 943                 /// HTML-encodes a string and sends the resulting output to a TextWriter output stream.
 944                 /// </summary>
 945                 /// <param name="s">The string to encode. </param>
 946                 /// <param name="output">The TextWriter output stream containing the encoded string. </param>
 947                 public static void HtmlEncode(string s, TextWriter output)
 948                 {
 949                         if (s != null)
 950                                 output.Write (HtmlEncode (s));
 951                 }
 952
 953 #if NET_1_1
 954                 public static string UrlPathEncode (string s)
 955                 {
 956                         if (s == null || s.Length == 0)
 957                                 return s;
 958
 959                         MemoryStream result = new MemoryStream ();
 960                         int length = s.Length;
 961             for (int i = 0; i < length; i++) {
 962                                 UrlPathEncodeChar (s [i], result);
 963                         }
 964                         return Encoding.ASCII.GetString (result.ToArray ());
 965                 }
 966
 967                 static void UrlPathEncodeChar (char c, Stream result) {
 968                         if (c > 127) {
 969                                 byte [] bIn = Encoding.UTF8.GetBytes (c.ToString ());
 970                                 for (int i = 0; i < bIn.Length; i++) {
 971                                         result.WriteByte ((byte) '%');
 972                                         int idx = ((int) bIn [i]) >> 4;
 973                                         result.WriteByte ((byte) hexChars [idx]);
 974                                         idx = ((int) bIn [i]) & 0x0F;
 975                                         result.WriteByte ((byte) hexChars [idx]);
 976                                 }
 977                         }
 978                         else if (c == ' ') {
 979                                 result.WriteByte ((byte) '%');
 980                                 result.WriteByte ((byte) '2');
 981                                 result.WriteByte ((byte) '0');
 982                         }
 983                         else
 984                                 result.WriteByte ((byte) c);
 985                 }
 986 #endif
 987
 988 #if NET_2_0
 989                 public static NameValueCollection ParseQueryString (string query)
 990                 {
 991                         return ParseQueryString (query, Encoding.UTF8);
 992                 }
 993
 994                 public static NameValueCollection ParseQueryString (string query, Encoding encoding)
 995                 {
 996                         if (query == null)
 997                                 throw new ArgumentNullException ("query");
 998                         if (encoding == null)
 999                                 throw new ArgumentNullException ("encoding");
1000                         if (query.Length == 0 || (query.Length == 1 && query[0] == '?'))
1001                                 return new NameValueCollection ();
1002                         if (query[0] == '?')
1003                                 query = query.Substring (1);
1004
1005                         NameValueCollection result = new NameValueCollection ();
1006                         ParseQueryString (query, encoding, result);
1007                         return result;
1008                 }
1009 #endif
1010
1011                 internal static void ParseQueryString (string query, Encoding encoding, NameValueCollection result)
1012                 {
1013                         if (query.Length == 0)
1014                                 return;
1015
1016                         int namePos = 0;
1017                         bool first = true;
1018                         while (namePos <= query.Length) {
1019                                 int valuePos = -1, valueEnd = -1;
1020                                 for (int q = namePos; q < query.Length; q++) {
1021                                         if (valuePos == -1 && query[q] == '=') {
1022                                                 valuePos = q + 1;
1023                                         } else if (query[q] == ';' || query[q] == '&') {
1024                                                 valueEnd = q;
1025                                                 break;
1026                                         }
1027                                 }
1028
1029                                 if (first) {
1030                                         first = false;
1031                                         if (query [namePos] == '?')
1032                                                 namePos++;
1033                                 }
1034
1035                                 string name, value;
1036                                 if (valuePos == -1) {
1037                                         name = null;
1038                                         valuePos = namePos;
1039                                 } else {
1040                                         name = UrlDecode (query.Substring (namePos, valuePos - namePos - 1), encoding);
1041                                 }
1042                                 if (valueEnd < 0) {
1043                                         namePos = -1;
1044                                         valueEnd = query.Length;
1045                                 } else {
1046                                         namePos = valueEnd + 1;
1047                                 }
1048                                 value = UrlDecode (query.Substring (valuePos, valueEnd - valuePos), encoding);
1049
1050                                 result.Add (name, value);
1051                                 if (namePos == -1)
1052                                         break;
1053                         }
1054                 }
1055                 #endregion // Methods
1056         }
1057 }
1058