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) 2005-2009 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.Generic;
  34 using System.Collections.Specialized;
  35 using System.Globalization;
  36 using System.IO;
  37 using System.Security.Permissions;
  38 using System.Text;
  39 using System.Web.Util;
  40
  41 namespace System.Web {
  42
  43 #if !MONOTOUCH
  44         // CAS - no InheritanceDemand here as the class is sealed
  45         [AspNetHostingPermission (SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
  46 #endif
  47         public sealed class HttpUtility
  48         {
  49                 sealed class HttpQSCollection : NameValueCollection
  50                 {
  51                         public override string ToString ()
  52                         {
  53                                 int count = Count;
  54                                 if (count == 0)
  55                                         return "";
  56                                 StringBuilder sb = new StringBuilder ();
  57                                 string [] keys = AllKeys;
  58                                 for (int i = 0; i < count; i++) {
  59                                         sb.AppendFormat ("{0}={1}&", keys [i], this [keys [i]]);
  60                                 }
  61                                 if (sb.Length > 0)
  62                                         sb.Length--;
  63                                 return sb.ToString ();
  64                         }
  65                 }
  66                 #region Fields
  67
  68                 static Hashtable entities;
  69                 static object lock_ = new object ();
  70
  71                 #endregion // Fields
  72
  73                 static Hashtable Entities {
  74                         get {
  75                                 lock (lock_) {
  76                                         if (entities == null)
  77                                                 InitEntities ();
  78
  79                                         return entities;
  80                                 }
  81                         }
  82                 }
  83
  84                 #region Constructors
  85
  86                 static void InitEntities ()
  87                 {
  88                         // Build the hash table of HTML entity references.  This list comes
  89                         // from the HTML 4.01 W3C recommendation.
  90                         entities = new Hashtable ();
  91                         entities.Add ("nbsp", '\u00A0');
  92                         entities.Add ("iexcl", '\u00A1');
  93                         entities.Add ("cent", '\u00A2');
  94                         entities.Add ("pound", '\u00A3');
  95                         entities.Add ("curren", '\u00A4');
  96                         entities.Add ("yen", '\u00A5');
  97                         entities.Add ("brvbar", '\u00A6');
  98                         entities.Add ("sect", '\u00A7');
  99                         entities.Add ("uml", '\u00A8');
 100                         entities.Add ("copy", '\u00A9');
 101                         entities.Add ("ordf", '\u00AA');
 102                         entities.Add ("laquo", '\u00AB');
 103                         entities.Add ("not", '\u00AC');
 104                         entities.Add ("shy", '\u00AD');
 105                         entities.Add ("reg", '\u00AE');
 106                         entities.Add ("macr", '\u00AF');
 107                         entities.Add ("deg", '\u00B0');
 108                         entities.Add ("plusmn", '\u00B1');
 109                         entities.Add ("sup2", '\u00B2');
 110                         entities.Add ("sup3", '\u00B3');
 111                         entities.Add ("acute", '\u00B4');
 112                         entities.Add ("micro", '\u00B5');
 113                         entities.Add ("para", '\u00B6');
 114                         entities.Add ("middot", '\u00B7');
 115                         entities.Add ("cedil", '\u00B8');
 116                         entities.Add ("sup1", '\u00B9');
 117                         entities.Add ("ordm", '\u00BA');
 118                         entities.Add ("raquo", '\u00BB');
 119                         entities.Add ("frac14", '\u00BC');
 120                         entities.Add ("frac12", '\u00BD');
 121                         entities.Add ("frac34", '\u00BE');
 122                         entities.Add ("iquest", '\u00BF');
 123                         entities.Add ("Agrave", '\u00C0');
 124                         entities.Add ("Aacute", '\u00C1');
 125                         entities.Add ("Acirc", '\u00C2');
 126                         entities.Add ("Atilde", '\u00C3');
 127                         entities.Add ("Auml", '\u00C4');
 128                         entities.Add ("Aring", '\u00C5');
 129                         entities.Add ("AElig", '\u00C6');
 130                         entities.Add ("Ccedil", '\u00C7');
 131                         entities.Add ("Egrave", '\u00C8');
 132                         entities.Add ("Eacute", '\u00C9');
 133                         entities.Add ("Ecirc", '\u00CA');
 134                         entities.Add ("Euml", '\u00CB');
 135                         entities.Add ("Igrave", '\u00CC');
 136                         entities.Add ("Iacute", '\u00CD');
 137                         entities.Add ("Icirc", '\u00CE');
 138                         entities.Add ("Iuml", '\u00CF');
 139                         entities.Add ("ETH", '\u00D0');
 140                         entities.Add ("Ntilde", '\u00D1');
 141                         entities.Add ("Ograve", '\u00D2');
 142                         entities.Add ("Oacute", '\u00D3');
 143                         entities.Add ("Ocirc", '\u00D4');
 144                         entities.Add ("Otilde", '\u00D5');
 145                         entities.Add ("Ouml", '\u00D6');
 146                         entities.Add ("times", '\u00D7');
 147                         entities.Add ("Oslash", '\u00D8');
 148                         entities.Add ("Ugrave", '\u00D9');
 149                         entities.Add ("Uacute", '\u00DA');
 150                         entities.Add ("Ucirc", '\u00DB');
 151                         entities.Add ("Uuml", '\u00DC');
 152                         entities.Add ("Yacute", '\u00DD');
 153                         entities.Add ("THORN", '\u00DE');
 154                         entities.Add ("szlig", '\u00DF');
 155                         entities.Add ("agrave", '\u00E0');
 156                         entities.Add ("aacute", '\u00E1');
 157                         entities.Add ("acirc", '\u00E2');
 158                         entities.Add ("atilde", '\u00E3');
 159                         entities.Add ("auml", '\u00E4');
 160                         entities.Add ("aring", '\u00E5');
 161                         entities.Add ("aelig", '\u00E6');
 162                         entities.Add ("ccedil", '\u00E7');
 163                         entities.Add ("egrave", '\u00E8');
 164                         entities.Add ("eacute", '\u00E9');
 165                         entities.Add ("ecirc", '\u00EA');
 166                         entities.Add ("euml", '\u00EB');
 167                         entities.Add ("igrave", '\u00EC');
 168                         entities.Add ("iacute", '\u00ED');
 169                         entities.Add ("icirc", '\u00EE');
 170                         entities.Add ("iuml", '\u00EF');
 171                         entities.Add ("eth", '\u00F0');
 172                         entities.Add ("ntilde", '\u00F1');
 173                         entities.Add ("ograve", '\u00F2');
 174                         entities.Add ("oacute", '\u00F3');
 175                         entities.Add ("ocirc", '\u00F4');
 176                         entities.Add ("otilde", '\u00F5');
 177                         entities.Add ("ouml", '\u00F6');
 178                         entities.Add ("divide", '\u00F7');
 179                         entities.Add ("oslash", '\u00F8');
 180                         entities.Add ("ugrave", '\u00F9');
 181                         entities.Add ("uacute", '\u00FA');
 182                         entities.Add ("ucirc", '\u00FB');
 183                         entities.Add ("uuml", '\u00FC');
 184                         entities.Add ("yacute", '\u00FD');
 185                         entities.Add ("thorn", '\u00FE');
 186                         entities.Add ("yuml", '\u00FF');
 187                         entities.Add ("fnof", '\u0192');
 188                         entities.Add ("Alpha", '\u0391');
 189                         entities.Add ("Beta", '\u0392');
 190                         entities.Add ("Gamma", '\u0393');
 191                         entities.Add ("Delta", '\u0394');
 192                         entities.Add ("Epsilon", '\u0395');
 193                         entities.Add ("Zeta", '\u0396');
 194                         entities.Add ("Eta", '\u0397');
 195                         entities.Add ("Theta", '\u0398');
 196                         entities.Add ("Iota", '\u0399');
 197                         entities.Add ("Kappa", '\u039A');
 198                         entities.Add ("Lambda", '\u039B');
 199                         entities.Add ("Mu", '\u039C');
 200                         entities.Add ("Nu", '\u039D');
 201                         entities.Add ("Xi", '\u039E');
 202                         entities.Add ("Omicron", '\u039F');
 203                         entities.Add ("Pi", '\u03A0');
 204                         entities.Add ("Rho", '\u03A1');
 205                         entities.Add ("Sigma", '\u03A3');
 206                         entities.Add ("Tau", '\u03A4');
 207                         entities.Add ("Upsilon", '\u03A5');
 208                         entities.Add ("Phi", '\u03A6');
 209                         entities.Add ("Chi", '\u03A7');
 210                         entities.Add ("Psi", '\u03A8');
 211                         entities.Add ("Omega", '\u03A9');
 212                         entities.Add ("alpha", '\u03B1');
 213                         entities.Add ("beta", '\u03B2');
 214                         entities.Add ("gamma", '\u03B3');
 215                         entities.Add ("delta", '\u03B4');
 216                         entities.Add ("epsilon", '\u03B5');
 217                         entities.Add ("zeta", '\u03B6');
 218                         entities.Add ("eta", '\u03B7');
 219                         entities.Add ("theta", '\u03B8');
 220                         entities.Add ("iota", '\u03B9');
 221                         entities.Add ("kappa", '\u03BA');
 222                         entities.Add ("lambda", '\u03BB');
 223                         entities.Add ("mu", '\u03BC');
 224                         entities.Add ("nu", '\u03BD');
 225                         entities.Add ("xi", '\u03BE');
 226                         entities.Add ("omicron", '\u03BF');
 227                         entities.Add ("pi", '\u03C0');
 228                         entities.Add ("rho", '\u03C1');
 229                         entities.Add ("sigmaf", '\u03C2');
 230                         entities.Add ("sigma", '\u03C3');
 231                         entities.Add ("tau", '\u03C4');
 232                         entities.Add ("upsilon", '\u03C5');
 233                         entities.Add ("phi", '\u03C6');
 234                         entities.Add ("chi", '\u03C7');
 235                         entities.Add ("psi", '\u03C8');
 236                         entities.Add ("omega", '\u03C9');
 237                         entities.Add ("thetasym", '\u03D1');
 238                         entities.Add ("upsih", '\u03D2');
 239                         entities.Add ("piv", '\u03D6');
 240                         entities.Add ("bull", '\u2022');
 241                         entities.Add ("hellip", '\u2026');
 242                         entities.Add ("prime", '\u2032');
 243                         entities.Add ("Prime", '\u2033');
 244                         entities.Add ("oline", '\u203E');
 245                         entities.Add ("frasl", '\u2044');
 246                         entities.Add ("weierp", '\u2118');
 247                         entities.Add ("image", '\u2111');
 248                         entities.Add ("real", '\u211C');
 249                         entities.Add ("trade", '\u2122');
 250                         entities.Add ("alefsym", '\u2135');
 251                         entities.Add ("larr", '\u2190');
 252                         entities.Add ("uarr", '\u2191');
 253                         entities.Add ("rarr", '\u2192');
 254                         entities.Add ("darr", '\u2193');
 255                         entities.Add ("harr", '\u2194');
 256                         entities.Add ("crarr", '\u21B5');
 257                         entities.Add ("lArr", '\u21D0');
 258                         entities.Add ("uArr", '\u21D1');
 259                         entities.Add ("rArr", '\u21D2');
 260                         entities.Add ("dArr", '\u21D3');
 261                         entities.Add ("hArr", '\u21D4');
 262                         entities.Add ("forall", '\u2200');
 263                         entities.Add ("part", '\u2202');
 264                         entities.Add ("exist", '\u2203');
 265                         entities.Add ("empty", '\u2205');
 266                         entities.Add ("nabla", '\u2207');
 267                         entities.Add ("isin", '\u2208');
 268                         entities.Add ("notin", '\u2209');
 269                         entities.Add ("ni", '\u220B');
 270                         entities.Add ("prod", '\u220F');
 271                         entities.Add ("sum", '\u2211');
 272                         entities.Add ("minus", '\u2212');
 273                         entities.Add ("lowast", '\u2217');
 274                         entities.Add ("radic", '\u221A');
 275                         entities.Add ("prop", '\u221D');
 276                         entities.Add ("infin", '\u221E');
 277                         entities.Add ("ang", '\u2220');
 278                         entities.Add ("and", '\u2227');
 279                         entities.Add ("or", '\u2228');
 280                         entities.Add ("cap", '\u2229');
 281                         entities.Add ("cup", '\u222A');
 282                         entities.Add ("int", '\u222B');
 283                         entities.Add ("there4", '\u2234');
 284                         entities.Add ("sim", '\u223C');
 285                         entities.Add ("cong", '\u2245');
 286                         entities.Add ("asymp", '\u2248');
 287                         entities.Add ("ne", '\u2260');
 288                         entities.Add ("equiv", '\u2261');
 289                         entities.Add ("le", '\u2264');
 290                         entities.Add ("ge", '\u2265');
 291                         entities.Add ("sub", '\u2282');
 292                         entities.Add ("sup", '\u2283');
 293                         entities.Add ("nsub", '\u2284');
 294                         entities.Add ("sube", '\u2286');
 295                         entities.Add ("supe", '\u2287');
 296                         entities.Add ("oplus", '\u2295');
 297                         entities.Add ("otimes", '\u2297');
 298                         entities.Add ("perp", '\u22A5');
 299                         entities.Add ("sdot", '\u22C5');
 300                         entities.Add ("lceil", '\u2308');
 301                         entities.Add ("rceil", '\u2309');
 302                         entities.Add ("lfloor", '\u230A');
 303                         entities.Add ("rfloor", '\u230B');
 304                         entities.Add ("lang", '\u2329');
 305                         entities.Add ("rang", '\u232A');
 306                         entities.Add ("loz", '\u25CA');
 307                         entities.Add ("spades", '\u2660');
 308                         entities.Add ("clubs", '\u2663');
 309                         entities.Add ("hearts", '\u2665');
 310                         entities.Add ("diams", '\u2666');
 311                         entities.Add ("quot", '\u0022');
 312                         entities.Add ("amp", '\u0026');
 313                         entities.Add ("lt", '\u003C');
 314                         entities.Add ("gt", '\u003E');
 315                         entities.Add ("OElig", '\u0152');
 316                         entities.Add ("oelig", '\u0153');
 317                         entities.Add ("Scaron", '\u0160');
 318                         entities.Add ("scaron", '\u0161');
 319                         entities.Add ("Yuml", '\u0178');
 320                         entities.Add ("circ", '\u02C6');
 321                         entities.Add ("tilde", '\u02DC');
 322                         entities.Add ("ensp", '\u2002');
 323                         entities.Add ("emsp", '\u2003');
 324                         entities.Add ("thinsp", '\u2009');
 325                         entities.Add ("zwnj", '\u200C');
 326                         entities.Add ("zwj", '\u200D');
 327                         entities.Add ("lrm", '\u200E');
 328                         entities.Add ("rlm", '\u200F');
 329                         entities.Add ("ndash", '\u2013');
 330                         entities.Add ("mdash", '\u2014');
 331                         entities.Add ("lsquo", '\u2018');
 332                         entities.Add ("rsquo", '\u2019');
 333                         entities.Add ("sbquo", '\u201A');
 334                         entities.Add ("ldquo", '\u201C');
 335                         entities.Add ("rdquo", '\u201D');
 336                         entities.Add ("bdquo", '\u201E');
 337                         entities.Add ("dagger", '\u2020');
 338                         entities.Add ("Dagger", '\u2021');
 339                         entities.Add ("permil", '\u2030');
 340                         entities.Add ("lsaquo", '\u2039');
 341                         entities.Add ("rsaquo", '\u203A');
 342                         entities.Add ("euro", '\u20AC');
 343                 }
 344
 345                 public HttpUtility ()
 346                 {
 347                 }
 348
 349                 #endregion // Constructors
 350
 351                 #region Methods
 352
 353                 public static void HtmlAttributeEncode (string s, TextWriter output)
 354                 {
 355                         output.Write(HtmlAttributeEncode(s));
 356                 }
 357
 358                 public static string HtmlAttributeEncode (string s)
 359                 {
 360                         if (null == s)
 361                                 return null;
 362
 363                         bool needEncode = false;
 364                         for (int i = 0; i < s.Length; i++) {
 365                                 if (s [i] == '&' || s [i] == '"' || s [i] == '<') {
 366                                         needEncode = true;
 367                                         break;
 368                                 }
 369                         }
 370
 371                         if (!needEncode)
 372                                 return s;
 373
 374                         StringBuilder output = new StringBuilder ();
 375                         int len = s.Length;
 376                         for (int i = 0; i < len; i++)
 377                                 switch (s [i]) {
 378                                 case '&' :
 379                                         output.Append ("&amp;");
 380                                         break;
 381                                 case '"' :
 382                                         output.Append ("&quot;");
 383                                         break;
 384                                 case '<':
 385                                         output.Append ("&lt;");
 386                                         break;
 387                                 default:
 388                                         output.Append (s [i]);
 389                                         break;
 390                                 }
 391
 392                         return output.ToString();
 393                 }
 394
 395                 public static string UrlDecode (string str)
 396                 {
 397                         return UrlDecode(str, Encoding.UTF8);
 398                 }
 399
 400                 static char [] GetChars (MemoryStream b, Encoding e)
 401                 {
 402                         return e.GetChars (b.GetBuffer (), 0, (int) b.Length);
 403                 }
 404
 405                 static void WriteCharBytes (IList buf, char ch, Encoding e)
 406                 {
 407                         if (ch > 255) {
 408                                 foreach (byte b in e.GetBytes (new char[] { ch }))
 409                                         buf.Add (b);
 410                         } else
 411                                 buf.Add ((byte)ch);
 412                 }
 413
 414                 public static string UrlDecode (string s, Encoding e)
 415                 {
 416                         if (null == s)
 417                                 return null;
 418
 419                         if (s.IndexOf ('%') == -1 && s.IndexOf ('+') == -1)
 420                                 return s;
 421
 422                         if (e == null)
 423                                 e = Encoding.UTF8;
 424
 425                         long len = s.Length;
 426                         var bytes = new List <byte> ();
 427                         int xchar;
 428                         char ch;
 429
 430                         for (int i = 0; i < len; i++) {
 431                                 ch = s [i];
 432                                 if (ch == '%' && i + 2 < len && s [i + 1] != '%') {
 433                                         if (s [i + 1] == 'u' && i + 5 < len) {
 434                                                 // unicode hex sequence
 435                                                 xchar = GetChar (s, i + 2, 4);
 436                                                 if (xchar != -1) {
 437                                                         WriteCharBytes (bytes, (char)xchar, e);
 438                                                         i += 5;
 439                                                 } else
 440                                                         WriteCharBytes (bytes, '%', e);
 441                                         } else if ((xchar = GetChar (s, i + 1, 2)) != -1) {
 442                                                 WriteCharBytes (bytes, (char)xchar, e);
 443                                                 i += 2;
 444                                         } else {
 445                                                 WriteCharBytes (bytes, '%', e);
 446                                         }
 447                                         continue;
 448                                 }
 449
 450                                 if (ch == '+')
 451                                         WriteCharBytes (bytes, ' ', e);
 452                                 else
 453                                         WriteCharBytes (bytes, ch, e);
 454                         }
 455
 456                         byte[] buf = bytes.ToArray ();
 457                         bytes = null;
 458                         return e.GetString (buf);
 459
 460                 }
 461
 462                 public static string UrlDecode (byte [] bytes, Encoding e)
 463                 {
 464                         if (bytes == null)
 465                                 return null;
 466
 467                         return UrlDecode (bytes, 0, bytes.Length, e);
 468                 }
 469
 470                 static int GetInt (byte b)
 471                 {
 472                         char c = (char) b;
 473                         if (c >= '0' && c <= '9')
 474                                 return c - '0';
 475
 476                         if (c >= 'a' && c <= 'f')
 477                                 return c - 'a' + 10;
 478
 479                         if (c >= 'A' && c <= 'F')
 480                                 return c - 'A' + 10;
 481
 482                         return -1;
 483                 }
 484
 485                 static int GetChar (byte [] bytes, int offset, int length)
 486                 {
 487                         int value = 0;
 488                         int end = length + offset;
 489                         for (int i = offset; i < end; i++) {
 490                                 int current = GetInt (bytes [i]);
 491                                 if (current == -1)
 492                                         return -1;
 493                                 value = (value << 4) + current;
 494                         }
 495
 496                         return value;
 497                 }
 498
 499                 static int GetChar (string str, int offset, int length)
 500                 {
 501                         int val = 0;
 502                         int end = length + offset;
 503                         for (int i = offset; i < end; i++) {
 504                                 char c = str [i];
 505                                 if (c > 127)
 506                                         return -1;
 507
 508                                 int current = GetInt ((byte) c);
 509                                 if (current == -1)
 510                                         return -1;
 511                                 val = (val << 4) + current;
 512                         }
 513
 514                         return val;
 515                 }
 516
 517                 public static string UrlDecode (byte [] bytes, int offset, int count, Encoding e)
 518                 {
 519                         if (bytes == null)
 520                                 return null;
 521                         if (count == 0)
 522                                 return String.Empty;
 523
 524                         if (bytes == null)
 525                                 throw new ArgumentNullException ("bytes");
 526
 527                         if (offset < 0 || offset > bytes.Length)
 528                                 throw new ArgumentOutOfRangeException ("offset");
 529
 530                         if (count < 0 || offset + count > bytes.Length)
 531                                 throw new ArgumentOutOfRangeException ("count");
 532
 533                         StringBuilder output = new StringBuilder ();
 534                         MemoryStream acc = new MemoryStream ();
 535
 536                         int end = count + offset;
 537                         int xchar;
 538                         for (int i = offset; i < end; i++) {
 539                                 if (bytes [i] == '%' && i + 2 < count && bytes [i + 1] != '%') {
 540                                         if (bytes [i + 1] == (byte) 'u' && i + 5 < end) {
 541                                                 if (acc.Length > 0) {
 542                                                         output.Append (GetChars (acc, e));
 543                                                         acc.SetLength (0);
 544                                                 }
 545                                                 xchar = GetChar (bytes, i + 2, 4);
 546                                                 if (xchar != -1) {
 547                                                         output.Append ((char) xchar);
 548                                                         i += 5;
 549                                                         continue;
 550                                                 }
 551                                         } else if ((xchar = GetChar (bytes, i + 1, 2)) != -1) {
 552                                                 acc.WriteByte ((byte) xchar);
 553                                                 i += 2;
 554                                                 continue;
 555                                         }
 556                                 }
 557
 558                                 if (acc.Length > 0) {
 559                                         output.Append (GetChars (acc, e));
 560                                         acc.SetLength (0);
 561                                 }
 562
 563                                 if (bytes [i] == '+') {
 564                                         output.Append (' ');
 565                                 } else {
 566                                         output.Append ((char) bytes [i]);
 567                                 }
 568                         }
 569
 570                         if (acc.Length > 0) {
 571                                 output.Append (GetChars (acc, e));
 572                         }
 573
 574                         acc = null;
 575                         return output.ToString ();
 576                 }
 577
 578                 public static byte [] UrlDecodeToBytes (byte [] bytes)
 579                 {
 580                         if (bytes == null)
 581                                 return null;
 582
 583                         return UrlDecodeToBytes (bytes, 0, bytes.Length);
 584                 }
 585
 586                 public static byte [] UrlDecodeToBytes (string str)
 587                 {
 588                         return UrlDecodeToBytes (str, Encoding.UTF8);
 589                 }
 590
 591                 public static byte [] UrlDecodeToBytes (string str, Encoding e)
 592                 {
 593                         if (str == null)
 594                                 return null;
 595
 596                         if (e == null)
 597                                 throw new ArgumentNullException ("e");
 598
 599                         return UrlDecodeToBytes (e.GetBytes (str));
 600                 }
 601
 602                 public static byte [] UrlDecodeToBytes (byte [] bytes, int offset, int count)
 603                 {
 604                         if (bytes == null)
 605                                 return null;
 606                         if (count == 0)
 607                                 return new byte [0];
 608
 609                         int len = bytes.Length;
 610                         if (offset < 0 || offset >= len)
 611                                 throw new ArgumentOutOfRangeException("offset");
 612
 613                         if (count < 0 || offset > len - count)
 614                                 throw new ArgumentOutOfRangeException("count");
 615
 616                         MemoryStream result = new MemoryStream ();
 617                         int end = offset + count;
 618                         for (int i = offset; i < end; i++){
 619                                 char c = (char) bytes [i];
 620                                 if (c == '+') {
 621                                         c = ' ';
 622                                 } else if (c == '%' && i < end - 2) {
 623                                         int xchar = GetChar (bytes, i + 1, 2);
 624                                         if (xchar != -1) {
 625                                                 c = (char) xchar;
 626                                                 i += 2;
 627                                         }
 628                                 }
 629                                 result.WriteByte ((byte) c);
 630                         }
 631
 632                         return result.ToArray ();
 633                 }
 634
 635                 public static string UrlEncode(string str)
 636                 {
 637                         return UrlEncode(str, Encoding.UTF8);
 638                 }
 639
 640                 public static string UrlEncode (string s, Encoding Enc)
 641                 {
 642                         if (s == null)
 643                                 return null;
 644
 645                         if (s == "")
 646                                 return "";
 647
 648                         bool needEncode = false;
 649                         int len = s.Length;
 650                         for (int i = 0; i < len; i++) {
 651                                 char c = s [i];
 652                                 if ((c < '0') || (c < 'A' && c > '9') || (c > 'Z' && c < 'a') || (c > 'z')) {
 653                                         if (NotEncoded (c))
 654                                                 continue;
 655
 656                                         needEncode = true;
 657                                         break;
 658                                 }
 659                         }
 660
 661                         if (!needEncode)
 662                                 return s;
 663
 664                         // avoided GetByteCount call
 665                         byte [] bytes = new byte[Enc.GetMaxByteCount(s.Length)];
 666                         int realLen = Enc.GetBytes (s, 0, s.Length, bytes, 0);
 667                         return Encoding.ASCII.GetString (UrlEncodeToBytes (bytes, 0, realLen));
 668                 }
 669
 670                 public static string UrlEncode (byte [] bytes)
 671                 {
 672                         if (bytes == null)
 673                                 return null;
 674
 675                         if (bytes.Length == 0)
 676                                 return "";
 677
 678                         return Encoding.ASCII.GetString (UrlEncodeToBytes (bytes, 0, bytes.Length));
 679                 }
 680
 681                 public static string UrlEncode (byte [] bytes, int offset, int count)
 682                 {
 683                         if (bytes == null)
 684                                 return null;
 685
 686                         if (bytes.Length == 0)
 687                                 return "";
 688
 689                         return Encoding.ASCII.GetString (UrlEncodeToBytes (bytes, offset, count));
 690                 }
 691
 692                 public static byte [] UrlEncodeToBytes (string str)
 693                 {
 694                         return UrlEncodeToBytes (str, Encoding.UTF8);
 695                 }
 696
 697                 public static byte [] UrlEncodeToBytes (string str, Encoding e)
 698                 {
 699                         if (str == null)
 700                                 return null;
 701
 702                         if (str == "")
 703                                 return new byte [0];
 704
 705                         byte [] bytes = e.GetBytes (str);
 706                         return UrlEncodeToBytes (bytes, 0, bytes.Length);
 707                 }
 708
 709                 public static byte [] UrlEncodeToBytes (byte [] bytes)
 710                 {
 711                         if (bytes == null)
 712                                 return null;
 713
 714                         if (bytes.Length == 0)
 715                                 return new byte [0];
 716
 717                         return UrlEncodeToBytes (bytes, 0, bytes.Length);
 718                 }
 719
 720                 static char [] hexChars = "0123456789abcdef".ToCharArray ();
 721
 722                 static bool NotEncoded (char c)
 723                 {
 724                         return (c == '!' || c == '\'' || c == '(' || c == ')' || c == '*' || c == '-' || c == '.' || c == '_');
 725                 }
 726
 727                 static void UrlEncodeChar (char c, Stream result, bool isUnicode) {
 728                         if (c > 255) {
 729                                 //FIXME: what happens when there is an internal error?
 730                                 //if (!isUnicode)
 731                                 //      throw new ArgumentOutOfRangeException ("c", c, "c must be less than 256");
 732                                 int idx;
 733                                 int i = (int) c;
 734
 735                                 result.WriteByte ((byte)'%');
 736                                 result.WriteByte ((byte)'u');
 737                                 idx = i >> 12;
 738                                 result.WriteByte ((byte)hexChars [idx]);
 739                                 idx = (i >> 8) & 0x0F;
 740                                 result.WriteByte ((byte)hexChars [idx]);
 741                                 idx = (i >> 4) & 0x0F;
 742                                 result.WriteByte ((byte)hexChars [idx]);
 743                                 idx = i & 0x0F;
 744                                 result.WriteByte ((byte)hexChars [idx]);
 745                                 return;
 746                         }
 747
 748                         if (c > ' ' && NotEncoded (c)) {
 749                                 result.WriteByte ((byte)c);
 750                                 return;
 751                         }
 752                         if (c==' ') {
 753                                 result.WriteByte ((byte)'+');
 754                                 return;
 755                         }
 756                         if (    (c < '0') ||
 757                                 (c < 'A' && c > '9') ||
 758                                 (c > 'Z' && c < 'a') ||
 759                                 (c > 'z')) {
 760                                 if (isUnicode && c > 127) {
 761                                         result.WriteByte ((byte)'%');
 762                                         result.WriteByte ((byte)'u');
 763                                         result.WriteByte ((byte)'0');
 764                                         result.WriteByte ((byte)'0');
 765                                 }
 766                                 else
 767                                         result.WriteByte ((byte)'%');
 768
 769                                 int idx = ((int) c) >> 4;
 770                                 result.WriteByte ((byte)hexChars [idx]);
 771                                 idx = ((int) c) & 0x0F;
 772                                 result.WriteByte ((byte)hexChars [idx]);
 773                         }
 774                         else
 775                                 result.WriteByte ((byte)c);
 776                 }
 777
 778                 public static byte [] UrlEncodeToBytes (byte [] bytes, int offset, int count)
 779                 {
 780                         if (bytes == null)
 781                                 return null;
 782
 783                         int len = bytes.Length;
 784                         if (len == 0)
 785                                 return new byte [0];
 786
 787                         if (offset < 0 || offset >= len)
 788                                 throw new ArgumentOutOfRangeException("offset");
 789
 790                         if (count < 0 || count > len - offset)
 791                                 throw new ArgumentOutOfRangeException("count");
 792
 793                         MemoryStream result = new MemoryStream (count);
 794                         int end = offset + count;
 795                         for (int i = offset; i < end; i++)
 796                                 UrlEncodeChar ((char)bytes [i], result, false);
 797
 798                         return result.ToArray();
 799                 }
 800
 801                 public static string UrlEncodeUnicode (string str)
 802                 {
 803                         if (str == null)
 804                                 return null;
 805
 806                         return Encoding.ASCII.GetString (UrlEncodeUnicodeToBytes (str));
 807                 }
 808
 809                 public static byte [] UrlEncodeUnicodeToBytes (string str)
 810                 {
 811                         if (str == null)
 812                                 return null;
 813
 814                         if (str == "")
 815                                 return new byte [0];
 816
 817                         MemoryStream result = new MemoryStream (str.Length);
 818                         foreach (char c in str){
 819                                 UrlEncodeChar (c, result, true);
 820                         }
 821                         return result.ToArray ();
 822                 }
 823
 824                 /// <summary>
 825                 /// Decodes an HTML-encoded string and returns the decoded string.
 826                 /// </summary>
 827                 /// <param name="s">The HTML string to decode. </param>
 828                 /// <returns>The decoded text.</returns>
 829                 public static string HtmlDecode (string s)
 830                 {
 831                         if (s == null)
 832                                 throw new ArgumentNullException ("s");
 833
 834                         if (s.IndexOf ('&') == -1)
 835                                 return s;
 836
 837                         StringBuilder entity = new StringBuilder ();
 838                         StringBuilder output = new StringBuilder ();
 839                         int len = s.Length;
 840                         // 0 -> nothing,
 841                         // 1 -> right after '&'
 842                         // 2 -> between '&' and ';' but no '#'
 843                         // 3 -> '#' found after '&' and getting numbers
 844                         int state = 0;
 845                         int number = 0;
 846                         bool have_trailing_digits = false;
 847
 848                         for (int i = 0; i < len; i++) {
 849                                 char c = s [i];
 850                                 if (state == 0) {
 851                                         if (c == '&') {
 852                                                 entity.Append (c);
 853                                                 state = 1;
 854                                         } else {
 855                                                 output.Append (c);
 856                                         }
 857                                         continue;
 858                                 }
 859
 860                                 if (c == '&') {
 861                                         state = 1;
 862                                         if (have_trailing_digits) {
 863                                                 entity.Append (number.ToString (Helpers.InvariantCulture));
 864                                                 have_trailing_digits = false;
 865                                         }
 866
 867                                         output.Append (entity.ToString ());
 868                                         entity.Length = 0;
 869                                         entity.Append ('&');
 870                                         continue;
 871                                 }
 872
 873                                 if (state == 1) {
 874                                         if (c == ';') {
 875                                                 state = 0;
 876                                                 output.Append (entity.ToString ());
 877                                                 output.Append (c);
 878                                                 entity.Length = 0;
 879                                         } else {
 880                                                 number = 0;
 881                                                 if (c != '#') {
 882                                                         state = 2;
 883                                                 } else {
 884                                                         state = 3;
 885                                                 }
 886                                                 entity.Append (c);
 887                                         }
 888                                 } else if (state == 2) {
 889                                         entity.Append (c);
 890                                         if (c == ';') {
 891                                                 string key = entity.ToString ();
 892                                                 if (key.Length > 1 && Entities.ContainsKey (key.Substring (1, key.Length - 2)))
 893                                                         key = Entities [key.Substring (1, key.Length - 2)].ToString ();
 894
 895                                                 output.Append (key);
 896                                                 state = 0;
 897                                                 entity.Length = 0;
 898                                         }
 899                                 } else if (state == 3) {
 900                                         if (c == ';') {
 901                                                 if (number > 65535) {
 902                                                         output.Append ("&#");
 903                                                         output.Append (number.ToString (Helpers.InvariantCulture));
 904                                                         output.Append (";");
 905                                                 } else {
 906                                                         output.Append ((char) number);
 907                                                 }
 908                                                 state = 0;
 909                                                 entity.Length = 0;
 910                                                 have_trailing_digits = false;
 911                                         } else if (Char.IsDigit (c)) {
 912                                                 number = number * 10 + ((int) c - '0');
 913                                                 have_trailing_digits = true;
 914                                         } else {
 915                                                 state = 2;
 916                                                 if (have_trailing_digits) {
 917                                                         entity.Append (number.ToString (Helpers.InvariantCulture));
 918                                                         have_trailing_digits = false;
 919                                                 }
 920                                                 entity.Append (c);
 921                                         }
 922                                 }
 923                         }
 924
 925                         if (entity.Length > 0) {
 926                                 output.Append (entity.ToString ());
 927                         } else if (have_trailing_digits) {
 928                                 output.Append (number.ToString (Helpers.InvariantCulture));
 929                         }
 930                         return output.ToString ();
 931                 }
 932
 933                 /// <summary>
 934                 /// Decodes an HTML-encoded string and sends the resulting output to a TextWriter output stream.
 935                 /// </summary>
 936                 /// <param name="s">The HTML string to decode</param>
 937                 /// <param name="output">The TextWriter output stream containing the decoded string. </param>
 938                 public static void HtmlDecode(string s, TextWriter output)
 939                 {
 940                         if (s != null)
 941                                 output.Write (HtmlDecode (s));
 942                 }
 943
 944                 /// <summary>
 945                 /// HTML-encodes a string and returns the encoded string.
 946                 /// </summary>
 947                 /// <param name="s">The text string to encode. </param>
 948                 /// <returns>The HTML-encoded text.</returns>
 949                 public static string HtmlEncode (string s)
 950                 {
 951                         if (s == null)
 952                                 return null;
 953
 954                         bool needEncode = false;
 955                         for (int i = 0; i < s.Length; i++) {
 956                                 char c = s [i];
 957                                 if (c == '&' || c == '"' || c == '<' || c == '>' || c > 159) {
 958                                         needEncode = true;
 959                                         break;
 960                                 }
 961                         }
 962
 963                         if (!needEncode)
 964                                 return s;
 965
 966                         StringBuilder output = new StringBuilder ();
 967
 968                         int len = s.Length;
 969                         for (int i = 0; i < len; i++)
 970                                 switch (s [i]) {
 971                                 case '&' :
 972                                         output.Append ("&amp;");
 973                                         break;
 974                                 case '>' :
 975                                         output.Append ("&gt;");
 976                                         break;
 977                                 case '<' :
 978                                         output.Append ("&lt;");
 979                                         break;
 980                                 case '"' :
 981                                         output.Append ("&quot;");
 982                                         break;
 983                                 default:
 984                                         // MS starts encoding with &# from 160 and stops at 255.
 985                                         // We don't do that. One reason is the 65308/65310 unicode
 986                                         // characters that look like '<' and '>'.
 987 #if TARGET_JVM
 988                                         if (s [i] > 159 && s [i] < 256) {
 989 #else
 990                                         if (s [i] > 159) {
 991 #endif
 992                                                 output.Append ("&#");
 993                                                 output.Append (((int) s [i]).ToString (Helpers.InvariantCulture));
 994                                                 output.Append (";");
 995                                         } else {
 996                                                 output.Append (s [i]);
 997                                         }
 998                                         break;
 999                                 }
1000                         return output.ToString ();
1001                 }
1002
1003                 /// <summary>
1004                 /// HTML-encodes a string and sends the resulting output to a TextWriter output stream.
1005                 /// </summary>
1006                 /// <param name="s">The string to encode. </param>
1007                 /// <param name="output">The TextWriter output stream containing the encoded string. </param>
1008                 public static void HtmlEncode(string s, TextWriter output)
1009                 {
1010                         if (s != null)
1011                                 output.Write (HtmlEncode (s));
1012                 }
1013
1014                 public static string UrlPathEncode (string s)
1015                 {
1016                         if (s == null || s.Length == 0)
1017                                 return s;
1018
1019                         MemoryStream result = new MemoryStream ();
1020                         int length = s.Length;
1021                         for (int i = 0; i < length; i++) {
1022                                 UrlPathEncodeChar (s [i], result);
1023                         }
1024                         return Encoding.ASCII.GetString (result.ToArray ());
1025                 }
1026
1027                 static void UrlPathEncodeChar (char c, Stream result)
1028                 {
1029                         if (c < 33 || c > 126) {
1030                                 byte [] bIn = Encoding.UTF8.GetBytes (c.ToString ());
1031                                 for (int i = 0; i < bIn.Length; i++) {
1032                                         result.WriteByte ((byte) '%');
1033                                         int idx = ((int) bIn [i]) >> 4;
1034                                         result.WriteByte ((byte) hexChars [idx]);
1035                                         idx = ((int) bIn [i]) & 0x0F;
1036                                         result.WriteByte ((byte) hexChars [idx]);
1037                                 }
1038                         }
1039                         else if (c == ' ') {
1040                                 result.WriteByte ((byte) '%');
1041                                 result.WriteByte ((byte) '2');
1042                                 result.WriteByte ((byte) '0');
1043                         }
1044                         else
1045                                 result.WriteByte ((byte) c);
1046                 }
1047
1048                 public static NameValueCollection ParseQueryString (string query)
1049                 {
1050                         return ParseQueryString (query, Encoding.UTF8);
1051                 }
1052
1053                 public static NameValueCollection ParseQueryString (string query, Encoding encoding)
1054                 {
1055                         if (query == null)
1056                                 throw new ArgumentNullException ("query");
1057                         if (encoding == null)
1058                                 throw new ArgumentNullException ("encoding");
1059                         if (query.Length == 0 || (query.Length == 1 && query[0] == '?'))
1060                                 return new NameValueCollection ();
1061                         if (query[0] == '?')
1062                                 query = query.Substring (1);
1063
1064                         NameValueCollection result = new HttpQSCollection ();
1065                         ParseQueryString (query, encoding, result);
1066                         return result;
1067                 }
1068
1069                 internal static void ParseQueryString (string query, Encoding encoding, NameValueCollection result)
1070                 {
1071                         if (query.Length == 0)
1072                                 return;
1073
1074                         string decoded = HtmlDecode (query);
1075                         int decodedLength = decoded.Length;
1076                         int namePos = 0;
1077                         bool first = true;
1078                         while (namePos <= decodedLength) {
1079                                 int valuePos = -1, valueEnd = -1;
1080                                 for (int q = namePos; q < decodedLength; q++) {
1081                                         if (valuePos == -1 && decoded [q] == '=') {
1082                                                 valuePos = q + 1;
1083                                         } else if (decoded [q] == '&') {
1084                                                 valueEnd = q;
1085                                                 break;
1086                                         }
1087                                 }
1088
1089                                 if (first) {
1090                                         first = false;
1091                                         if (decoded [namePos] == '?')
1092                                                 namePos++;
1093                                 }
1094
1095                                 string name, value;
1096                                 if (valuePos == -1) {
1097                                         name = null;
1098                                         valuePos = namePos;
1099                                 } else {
1100                                         name = UrlDecode (decoded.Substring (namePos, valuePos - namePos - 1), encoding);
1101                                 }
1102                                 if (valueEnd < 0) {
1103                                         namePos = -1;
1104                                         valueEnd = decoded.Length;
1105                                 } else {
1106                                         namePos = valueEnd + 1;
1107                                 }
1108                                 value = UrlDecode (decoded.Substring (valuePos, valueEnd - valuePos), encoding);
1109
1110                                 result.Add (name, value);
1111                                 if (namePos == -1)
1112                                         break;
1113                         }
1114                 }
1115                 #endregion // Methods
1116         }
1117 }
1118