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                         NumberStyles hexa = NumberStyles.HexNumber;
 387                         MemoryStream bytes = new MemoryStream ();
 388
 389                         for (int i = 0; i < len; i++) {
 390                                 if (s [i] == '%' && i + 2 < len) {
 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                                                 output.Append ((char) Int32.Parse (s.Substring (i + 2, 4), hexa));
 397                                                 i += 5;
 398                                         } else {
 399                                                 bytes.WriteByte ((byte) Int32.Parse (s.Substring (i + 1, 2), hexa));
 400                                                 i += 2;
 401                                         }
 402                                         continue;
 403                                 }
 404
 405                                 if (bytes.Length > 0) {
 406                                         output.Append (GetChars (bytes, e));
 407                                         bytes.SetLength (0);
 408                                 }
 409
 410                                 if (s [i] == '+') {
 411                                         output.Append (' ');
 412                                 } else {
 413                                         output.Append (s [i]);
 414                                 }
 415                         }
 416
 417                         if (bytes.Length > 0) {
 418                                 output.Append (GetChars (bytes, e));
 419                         }
 420
 421                         bytes = null;
 422                         return output.ToString ();
 423                 }
 424
 425                 public static string UrlDecode (byte [] bytes, Encoding e)
 426                 {
 427                         if (bytes == null)
 428                                 return null;
 429
 430                         return UrlDecode (bytes, 0, bytes.Length, e);
 431                 }
 432
 433                 private static int GetInt (byte b)
 434                 {
 435                         char c = Char.ToUpper ((char) b);
 436                         if (c >= '0' && c <= '9')
 437                                 return c - '0';
 438
 439                         if (c < 'A' || c > 'F')
 440                                 return 0;
 441
 442                         return (c - 'A' + 10);
 443                 }
 444
 445                 private static char GetChar (byte [] bytes, int offset, int length)
 446                 {
 447                         int value = 0;
 448                         int end = length + offset;
 449                         for (int i = offset; i < end; i++)
 450                                 value = (value << 4) + GetInt (bytes [i]);
 451
 452                         return (char) value;
 453                 }
 454
 455                 public static string UrlDecode (byte [] bytes, int offset, int count, Encoding e)
 456                 {
 457                         if (bytes == null)
 458                                 return null;
 459                         if (count == 0)
 460                                 return String.Empty;
 461
 462                         if (bytes == null)
 463                                 throw new ArgumentNullException ("bytes");
 464
 465                         if (offset < 0 || offset > bytes.Length)
 466                                 throw new ArgumentOutOfRangeException ("offset");
 467
 468                         if (count < 0 || offset + count > bytes.Length)
 469                                 throw new ArgumentOutOfRangeException ("count");
 470
 471                         StringBuilder output = new StringBuilder ();
 472                         MemoryStream acc = new MemoryStream ();
 473
 474                         int end = count + offset;
 475                         for (int i = offset; i < end; i++) {
 476                                 if (bytes [i] == '%' && i + 2 < count) {
 477                                         if (bytes [i + 1] == (byte) 'u' && i + 5 < end) {
 478                                                 if (acc.Length > 0) {
 479                                                         output.Append (GetChars (acc, e));
 480                                                         acc.SetLength (0);
 481                                                 }
 482                                                 output.Append (GetChar (bytes, i + 2, 4));
 483                                                 i += 5;
 484                                         } else {
 485                                                 acc.WriteByte ((byte) GetChar (bytes, i + 1, 2));
 486                                                 i += 2;
 487                                         }
 488                                         continue;
 489                                 }
 490
 491                                 if (acc.Length > 0) {
 492                                         output.Append (GetChars (acc, e));
 493                                         acc.SetLength (0);
 494                                 }
 495
 496                                 if (bytes [i] == '+') {
 497                                         output.Append (' ');
 498                                 } else {
 499                                         output.Append ((char) bytes [i]);
 500                                 }
 501                         }
 502
 503                         if (acc.Length > 0) {
 504                                 output.Append (GetChars (acc, e));
 505                         }
 506
 507                         acc = null;
 508                         return output.ToString ();
 509                 }
 510
 511                 public static byte [] UrlDecodeToBytes (byte [] bytes)
 512                 {
 513                         if (bytes == null)
 514                                 return null;
 515
 516                         return UrlDecodeToBytes (bytes, 0, bytes.Length);
 517                 }
 518
 519                 public static byte [] UrlDecodeToBytes (string str)
 520                 {
 521                         return UrlDecodeToBytes (str, Encoding.UTF8);
 522                 }
 523
 524                 public static byte [] UrlDecodeToBytes (string str, Encoding e)
 525                 {
 526                         if (str == null)
 527                                 return null;
 528
 529                         if (e == null)
 530                                 throw new ArgumentNullException ("e");
 531
 532                         return UrlDecodeToBytes (e.GetBytes (str));
 533                 }
 534
 535                 public static byte [] UrlDecodeToBytes (byte [] bytes, int offset, int count)
 536                 {
 537                         if (bytes == null)
 538                                 return null;
 539                         if (count == 0)
 540                                 return new byte [0];
 541
 542                         int len = bytes.Length;
 543                         if (offset < 0 || offset >= len)
 544                                 throw new ArgumentOutOfRangeException("offset");
 545
 546                         if (count < 0 || offset > len - count)
 547                                 throw new ArgumentOutOfRangeException("count");
 548
 549                         MemoryStream result = new MemoryStream ();
 550                         int end = offset + count;
 551                         for (int i = offset; i < end; i++){
 552                                 char c = (char) bytes [i];
 553                                 if (c == '+')
 554                                         c = ' ';
 555                                 else if (c == '%' && i < end - 2) {
 556                                         c = GetChar (bytes, i + 1, 2);
 557                                         i += 2;
 558                                 }
 559                                 result.WriteByte ((byte) c);
 560                         }
 561
 562                         return result.ToArray ();
 563                 }
 564
 565                 public static string UrlEncode(string str)
 566                 {
 567                         return UrlEncode(str, Encoding.UTF8);
 568                 }
 569
 570                 public static string UrlEncode (string s, Encoding Enc)
 571                 {
 572                         if (s == null)
 573                                 return null;
 574
 575                         if (s == "")
 576                                 return "";
 577
 578                         byte [] bytes = Enc.GetBytes (s);
 579                         return Encoding.ASCII.GetString (UrlEncodeToBytes (bytes, 0, bytes.Length));
 580                 }
 581
 582                 public static string UrlEncode (byte [] bytes)
 583                 {
 584                         if (bytes == null)
 585                                 return null;
 586
 587                         if (bytes.Length == 0)
 588                                 return "";
 589
 590                         return Encoding.ASCII.GetString (UrlEncodeToBytes (bytes, 0, bytes.Length));
 591                 }
 592
 593                 public static string UrlEncode (byte [] bytes, int offset, int count)
 594                 {
 595                         if (bytes == null)
 596                                 return null;
 597
 598                         if (bytes.Length == 0)
 599                                 return "";
 600
 601                         return Encoding.ASCII.GetString (UrlEncodeToBytes (bytes, offset, count));
 602                 }
 603
 604                 public static byte [] UrlEncodeToBytes (string str)
 605                 {
 606                         return UrlEncodeToBytes (str, Encoding.UTF8);
 607                 }
 608
 609                 public static byte [] UrlEncodeToBytes (string str, Encoding e)
 610                 {
 611                         if (str == null)
 612                                 return null;
 613
 614                         if (str == "")
 615                                 return new byte [0];
 616
 617                         byte [] bytes = e.GetBytes (str);
 618                         return UrlEncodeToBytes (bytes, 0, bytes.Length);
 619                 }
 620
 621                 public static byte [] UrlEncodeToBytes (byte [] bytes)
 622                 {
 623                         if (bytes == null)
 624                                 return null;
 625
 626                         if (bytes.Length == 0)
 627                                 return new byte [0];
 628
 629                         return UrlEncodeToBytes (bytes, 0, bytes.Length);
 630                 }
 631
 632                 static char [] hexChars = "0123456789abcdef".ToCharArray ();
 633
 634                 public static byte [] UrlEncodeToBytes (byte [] bytes, int offset, int count)
 635                 {
 636                         if (bytes == null)
 637                                 return null;
 638
 639                         int len = bytes.Length;
 640                         if (len == 0)
 641                                 return new byte [0];
 642
 643                         if (offset < 0 || offset >= len)
 644                                 throw new ArgumentOutOfRangeException("offset");
 645
 646                         if (count < 0 || count > len - offset)
 647                                 throw new ArgumentOutOfRangeException("count");
 648
 649                         MemoryStream result = new MemoryStream ();
 650                         int end = offset + count;
 651                         for (int i = offset; i < end; i++) {
 652                                 char c = (char) bytes [i];
 653                                 if ((c == ' ') || (c < '0' && c != '-' && c != '.') ||
 654                                     (c < 'A' && c > '9') ||
 655                                     (c > 'Z' && c < 'a' && c != '_') ||
 656                                     (c > 'z')) {
 657                                         result.WriteByte ((byte) '%');
 658                                         int idx = ((int) c) >> 4;
 659                                         result.WriteByte ((byte) hexChars [idx]);
 660                                         idx = ((int) c) & 0x0F;
 661                                         result.WriteByte ((byte) hexChars [idx]);
 662                                 } else {
 663                                         result.WriteByte ((byte) c);
 664                                 }
 665                         }
 666
 667                         return result.ToArray ();
 668                 }
 669
 670                 public static string UrlEncodeUnicode (string str)
 671                 {
 672                         if (str == null)
 673                                 return null;
 674
 675                         StringBuilder result = new StringBuilder ();
 676                         foreach (char c in str){
 677                                 int idx;
 678
 679                                 if (c > 255) {
 680                                         result.Append ("%u");
 681                                         idx = ((int) c) >> 24;
 682                                         result.Append (hexChars [idx]);
 683                                         idx = (((int) c) >> 16) & 0x0F;
 684                                         result.Append (hexChars [idx]);
 685                                         idx = (((int) c) >> 8) & 0x0F;
 686                                         result.Append (hexChars [idx]);
 687                                         idx = ((int) c) & 0x0F;
 688                                         result.Append (hexChars [idx]);
 689                                         continue;
 690                                 }
 691
 692                                 if ((c == ' ') || (c < '0' && c != '-' && c != '.') ||
 693                                     (c < 'A' && c > '9') ||
 694                                     (c > 'Z' && c < 'a' && c != '_') ||
 695                                     (c > 'z')) {
 696                                         result.Append ("%00");
 697                                         idx = ((int) c) >> 4;
 698                                         result.Append (hexChars [idx]);
 699                                         idx = ((int) c) & 0x0F;
 700                                         result.Append (hexChars [idx]);
 701                                         continue;
 702                                 }
 703
 704                                 result.Append (c);
 705                         }
 706
 707                         return result.ToString ();
 708                 }
 709
 710                 public static byte [] UrlEncodeUnicodeToBytes (string str)
 711                 {
 712                         if (str == null)
 713                                 return null;
 714
 715                         if (str == "")
 716                                 return new byte [0];
 717
 718                         return Encoding.ASCII.GetBytes (UrlEncodeUnicode (str));
 719                 }
 720
 721                 /// <summary>
 722                 /// Decodes an HTML-encoded string and returns the decoded string.
 723                 /// </summary>
 724                 /// <param name="s">The HTML string to decode. </param>
 725                 /// <returns>The decoded text.</returns>
 726                 public static string HtmlDecode (string s)
 727                 {
 728                         if (s == null)
 729                                 throw new ArgumentNullException ("s");
 730
 731                         if (s.IndexOf ('&') == -1)
 732                                 return s;
 733
 734                         StringBuilder entity = new StringBuilder ();
 735                         StringBuilder output = new StringBuilder ();
 736                         int len = s.Length;
 737                         // 0 -> nothing,
 738                         // 1 -> right after '&'
 739                         // 2 -> between '&' and ';' but no '#'
 740                         // 3 -> '#' found after '&' and getting numbers
 741                         int state = 0;
 742                         int number = 0;
 743                         bool have_trailing_digits = false;
 744
 745                         for (int i = 0; i < len; i++) {
 746                                 char c = s [i];
 747                                 if (state == 0) {
 748                                         if (c == '&') {
 749                                                 entity.Append (c);
 750                                                 state = 1;
 751                                         } else {
 752                                                 output.Append (c);
 753                                         }
 754                                         continue;
 755                                 }
 756
 757                                 if (c == '&') {
 758                                         state = 1;
 759                                         if (have_trailing_digits) {
 760                                                 entity.Append (number.ToString (CultureInfo.InvariantCulture));
 761                                                 have_trailing_digits = false;
 762                                         }
 763
 764                                         output.Append (entity.ToString ());
 765                                         entity.Length = 0;
 766                                         entity.Append ('&');
 767                                         continue;
 768                                 }
 769
 770                                 if (state == 1) {
 771                                         if (c == ';') {
 772                                                 state = 0;
 773                                                 output.Append (entity.ToString ());
 774                                                 output.Append (c);
 775                                                 entity.Length = 0;
 776                                         } else {
 777                                                 number = 0;
 778                                                 if (c != '#') {
 779                                                         state = 2;
 780                                                 } else {
 781                                                         state = 3;
 782                                                 }
 783                                                 entity.Append (c);
 784                                         }
 785                                 } else if (state == 2) {
 786                                         entity.Append (c);
 787                                         if (c == ';') {
 788                                                 string key = entity.ToString ();
 789                                                 if (key.Length > 1 && Entities.ContainsKey (key.Substring (1, key.Length - 2)))
 790                                                         key = Entities [key.Substring (1, key.Length - 2)].ToString ();
 791
 792                                                 output.Append (key);
 793                                                 state = 0;
 794                                                 entity.Length = 0;
 795                                         }
 796                                 } else if (state == 3) {
 797                                         if (c == ';') {
 798                                                 if (number > 65535) {
 799                                                         output.Append ("&#");
 800                                                         output.Append (number.ToString (CultureInfo.InvariantCulture));
 801                                                         output.Append (";");
 802                                                 } else {
 803                                                         output.Append ((char) number);
 804                                                 }
 805                                                 state = 0;
 806                                                 entity.Length = 0;
 807                                                 have_trailing_digits = false;
 808                                         } else if (Char.IsDigit (c)) {
 809                                                 number = number * 10 + ((int) c - '0');
 810                                                 have_trailing_digits = true;
 811                                         } else {
 812                                                 state = 2;
 813                                                 if (have_trailing_digits) {
 814                                                         entity.Append (number.ToString (CultureInfo.InvariantCulture));
 815                                                         have_trailing_digits = false;
 816                                                 }
 817                                                 entity.Append (c);
 818                                         }
 819                                 }
 820                         }
 821
 822                         if (entity.Length > 0) {
 823                                 output.Append (entity.ToString ());
 824                         } else if (have_trailing_digits) {
 825                                 output.Append (number.ToString (CultureInfo.InvariantCulture));
 826                         }
 827                         return output.ToString ();
 828                 }
 829
 830                 /// <summary>
 831                 /// Decodes an HTML-encoded string and sends the resulting output to a TextWriter output stream.
 832                 /// </summary>
 833                 /// <param name="s">The HTML string to decode</param>
 834                 /// <param name="output">The TextWriter output stream containing the decoded string. </param>
 835                 public static void HtmlDecode(string s, TextWriter output)
 836                 {
 837                         if (s != null)
 838                                 output.Write (HtmlDecode (s));
 839                 }
 840
 841                 /// <summary>
 842                 /// HTML-encodes a string and returns the encoded string.
 843                 /// </summary>
 844                 /// <param name="s">The text string to encode. </param>
 845                 /// <returns>The HTML-encoded text.</returns>
 846                 public static string HtmlEncode (string s)
 847                 {
 848                         if (s == null)
 849                                 return null;
 850
 851                         StringBuilder output = new StringBuilder ();
 852
 853                         foreach (char c in s)
 854                                 switch (c) {
 855                                 case '&' :
 856                                         output.Append ("&amp;");
 857                                         break;
 858                                 case '>' :
 859                                         output.Append ("&gt;");
 860                                         break;
 861                                 case '<' :
 862                                         output.Append ("&lt;");
 863                                         break;
 864                                 case '"' :
 865                                         output.Append ("&quot;");
 866                                         break;
 867                                 default:
 868                                         // MS starts encoding with &# from 160 and stops at 255.
 869                                         // We don't do that. One reason is the 65308/65310 unicode
 870                                         // characters that look like '<' and '>'.
 871                                         if (c > 159) {
 872                                                 output.Append ("&#");
 873                                                 output.Append (((int) c).ToString (CultureInfo.InvariantCulture));
 874                                                 output.Append (";");
 875                                         } else {
 876                                                 output.Append (c);
 877                                         }
 878                                         break;
 879                                 }
 880                         return output.ToString ();
 881                 }
 882
 883                 /// <summary>
 884                 /// HTML-encodes a string and sends the resulting output to a TextWriter output stream.
 885                 /// </summary>
 886                 /// <param name="s">The string to encode. </param>
 887                 /// <param name="output">The TextWriter output stream containing the encoded string. </param>
 888                 public static void HtmlEncode(string s, TextWriter output)
 889                 {
 890                         if (s != null)
 891                                 output.Write (HtmlEncode (s));
 892                 }
 893
 894 #if NET_1_1
 895                 public static string UrlPathEncode (string s)
 896                 {
 897                         if (s == null)
 898                                 return null;
 899
 900                         int idx = s.IndexOf ("?");
 901                         string s2 = null;
 902                         if (idx != -1) {
 903                                 s2 = s.Substring (0, idx-1);
 904                                 s2 = UrlEncode (s2) + s.Substring (idx);
 905                         } else {
 906                                 s2 = UrlEncode (s);
 907                         }
 908
 909                         return s2;
 910                 }
 911 #endif
 912
 913 #if NET_2_0
 914                 [MonoTODO]
 915                 public static NameValueCollection ParseQueryString (string query)
 916                 {
 917                         // LAMESPEC: default encoding not specified
 918                         throw new NotImplementedException ();
 919                 }
 920
 921                 [MonoTODO]
 922                 public static NameValueCollection ParseQueryString (string query, Encoding encoding)
 923                 {
 924                         throw new NotImplementedException ();
 925                 }
 926 #endif
 927                 #endregion // Methods
 928         }
 929 }
 930