mcs/class/corlib/System/String.cs

   1 // -*- Mode: C++; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*-
   2 //
   3 // System.String.cs
   4 //
   5 // Author:
   6 //   Jeffrey Stedfast (fejj@ximian.com)
   7 //
   8 // (C) 2001 Ximian, Inc.  http://www.ximian.com
   9 //
  10
  11 // FIXME: from what I gather from msdn, when a function is to return an empty string
  12 //        we should be returning this.Empty - some methods do this and others don't.
  13
  14 // FIXME: I didn't realise until later that `string' has a .Length method and so
  15 //        I am missing some proper bounds-checking in some methods. Find these
  16 //        instances and throw the ArgumentOutOfBoundsException at the programmer.
  17 //        I like pelting programmers with ArgumentOutOfBoundsException's :-)
  18
  19 // FIXME: The ToLower(), ToUpper(), and Compare(..., bool ignoreCase) methods
  20 //        need to be made unicode aware.
  21
  22 // FIXME: when you have a char carr[], does carr.Length include the terminating null char?
  23
  24 using System;
  25 using System.Text;
  26 using System.Collections;
  27 using System.Globalization;
  28 using System.Runtime.CompilerServices;
  29
  30 namespace System {
  31
  32         public sealed class String : IComparable, ICloneable, IConvertible, IEnumerable {
  33                 public static readonly string Empty = "";
  34                 private char[] c_str;
  35                 private int length;
  36
  37                 // Constructors
  38                 unsafe public String (char *value)
  39                 {
  40                         int i;
  41
  42                         // FIXME: can I do value.Length here?
  43                         if (value == null) {
  44                                 this.length = 0;
  45                         } else {
  46                                 for (i = 0; *(value + i) != '\0'; i++);
  47                                 this.length = i;
  48                         }
  49
  50                         this.c_str = new char [this.length + 1];
  51                         for (i = 0; i < this.length; i++)
  52                                 this.c_str[i] = *(value + i);
  53                         this.c_str[i] = '\0';
  54                 }
  55
  56                 public String (char[] value)
  57                 {
  58                         int i;
  59
  60                         // FIXME: value.Length includes the terminating null char?
  61                         this.length = value != null ? strlen (value): 0;
  62                         this.c_str = new char [this.length + 1];
  63                         for (i = 0; i < this.length; i++)
  64                                 this.c_str[i] = value[i];
  65                         this.c_str[i] = '\0';
  66                 }
  67
  68                 unsafe public String (sbyte *value)
  69                 {
  70                         // FIXME: consider unicode?
  71                         int i;
  72
  73                         // FIXME: can I do value.Length here? */
  74                         if (value == null) {
  75                                 this.length = 0;
  76                         } else {
  77                                 for (i = 0; *(value + i) != '\0'; i++);
  78                                 this.length = i;
  79                         }
  80
  81                         this.c_str = new char [this.length + 1];
  82                         for (i = 0; i < this.length; i++)
  83                                 this.c_str[i] = (char) *(value + i);
  84                         this.c_str[i] = '\0';
  85                 }
  86
  87                 public String (char c, int count)
  88                 {
  89                         int i;
  90
  91                         this.length = count;
  92                         this.c_str = new char [count + 1];
  93                         for (i = 0; i < count; i++)
  94                                 this.c_str[i] = c;
  95                         this.c_str[i] = '\0';
  96                 }
  97
  98                 unsafe public String (char *value, int startIndex, int length)
  99                 {
 100                         int i;
 101
 102                         if (value == null && startIndex != 0 && length != 0)
 103                                 throw new ArgumentNullException ();
 104
 105                         if (startIndex < 0 || length < 0)
 106                                 throw new ArgumentOutOfRangeException ();
 107
 108                         this.length = length;
 109                         this.c_str = new char [length + 1];
 110                         for (i = 0; i < length; i++)
 111                                 this.c_str[i] = *(value + startIndex + i);
 112                         this.c_str[i] = '\0';
 113                 }
 114
 115                 public String (char[] value, int startIndex, int length)
 116                 {
 117                         int i;
 118
 119                         if (value == null && startIndex != 0 && length != 0)
 120                                 throw new ArgumentNullException ();
 121
 122                         if (startIndex < 0 || length < 0)
 123                                 throw new ArgumentOutOfRangeException ();
 124
 125                         this.length = length;
 126                         this.c_str = new char [length + 1];
 127                         for (i = 0; i < length; i++)
 128                                 this.c_str[i] = value[startIndex + i];
 129                         this.c_str[i] = '\0';
 130                 }
 131
 132                 unsafe public String (sbyte *value, int startIndex, int length)
 133                 {
 134                         // FIXME: consider unicode?
 135                         int i;
 136
 137                         if (value == null && startIndex != 0 && length != 0)
 138                                 throw new ArgumentNullException ();
 139
 140                         if (startIndex < 0 || length < 0)
 141                                 throw new ArgumentOutOfRangeException ();
 142
 143                         this.length = length;
 144                         this.c_str = new char [length + 1];
 145                         for (i = 0; i < length; i++)
 146                                 this.c_str[i] = (char) *(value + startIndex + i);
 147                         this.c_str[i] = '\0';
 148                 }
 149
 150                 unsafe public String (sbyte *value, int startIndex, int length, Encoding enc)
 151                 {
 152                         // FIXME: implement me
 153                 }
 154
 155                 ~String ()
 156                 {
 157                         // FIXME: is there anything we need to do here?
 158                         /*base.Finalize ();*/
 159                 }
 160
 161                 // Properties
 162                 public int Length {
 163                         get {
 164                                 return this.length;
 165                         }
 166                 }
 167
 168                 // FIXME: is this correct syntax??
 169                 public char this [int index] {
 170                         get {
 171                                 if (index > this.length)
 172                                         throw new ArgumentOutOfRangeException ();
 173
 174                                 return this.c_str[index];
 175                         }
 176                 }
 177
 178                 // Private helper methods
 179                 private static int strlen (char[] str)
 180                 {
 181                         // FIXME: if str.Length includes terminating null char, then return (str.Length - 1)
 182                         return str.Length;
 183                 }
 184
 185                 private static char tolowerordinal (char c)
 186                 {
 187                         // FIXME: implement me
 188                         return c;
 189                 }
 190
 191                 private static bool is_lwsp (char c)
 192                 {
 193                         /* this comes from the msdn docs for String.Trim() */
 194                         if ((c >= '\x9' && c <= '\xD') || c == '\x20' || c == '\xA0' ||
 195                             (c >= '\x2000' && c <= '\x200B') || c == '\x3000' || c == '\xFEFF')
 196                                 return true;
 197                         else
 198                                 return false;
 199                 }
 200
 201                 private static int BoyerMoore (char[] haystack, string needle, int startIndex, int count)
 202                 {
 203                         /* (hopefully) Unicode-safe Boyer-Moore implementation */
 204                         int[] skiptable = new int[65536];  /* our unicode-safe skip-table */
 205                         int h, n, he, ne, hc, nc, i;
 206
 207                         if (haystack == null || needle == null)
 208                                 throw new ArgumentNullException ();
 209
 210                         /* if the search buffer is shorter than the pattern buffer, we can't match */
 211                         if (count < needle.Length)
 212                                 return -1;
 213
 214                         /* return an instant match if the pattern is 0-length */
 215                         if (needle.Length == 0)
 216                                 return startIndex;
 217
 218                         /* set a pointer at the end of each string */
 219                         ne = needle.Length - 1;      /* position of char before '\0' */
 220                         he = startIndex + count;     /* position of last valid char */
 221
 222                         /* init the skip table with the pattern length */
 223                         for (i = 0; i < 65536; i++)
 224                                 skiptable[i] = needle.Length;
 225
 226                         /* set the skip value for the chars that *do* appear in the
 227                          * pattern buffer (needle) to the distance from the index to
 228                          * the end of the pattern buffer. */
 229                         for (nc = 0; nc < ne; nc++)
 230                                 skiptable[(int) needle[nc]] = ne - nc;
 231
 232                         h = startIndex;
 233                         while (count >= needle.Length) {
 234                                 hc = h + needle.Length - 1;  /* set the haystack compare pointer */
 235                                 nc = ne;                     /* set the needle compare pointer */
 236
 237                                 /* work our way backwards until they don't match */
 238                                 for (i = 0; nc > 0; nc--, hc--, i++)
 239                                         if (needle[nc] != haystack[hc])
 240                                                 break;
 241
 242                                 if (needle[nc] != haystack[hc]) {
 243                                         n = skiptable[(int) haystack[hc]] - i;
 244                                         h += n;
 245                                         count -= n;
 246                                 } else
 247                                         return h;
 248                         }
 249
 250                         return -1;
 251                 }
 252
 253                 // Methods
 254                 public object Clone ()
 255                 {
 256                         // FIXME: implement me
 257                         return null;
 258                 }
 259
 260                 public static int Compare (string strA, string strB)
 261                 {
 262                         int i;
 263
 264                         /* Does this remind anyone of the nautilus string.h wrappers? ;-) */
 265                         if (strA == null) {
 266                                 if (strB == null)
 267                                         return 0;
 268                                 else
 269                                         return -1;
 270                         } else if (strB == null)
 271                                 return 1;
 272
 273                         for (i = 0; strA[i] == strB[i] && strA[i] != '\0'; i++);
 274
 275                         return ((int) (strA[i] - strB[i]));
 276                 }
 277
 278                 public static int Compare (string strA, string strB, bool ignoreCase)
 279                 {
 280                         int i;
 281
 282                         if (!ignoreCase)
 283                                 return Compare (strA, strB);
 284
 285                         /*
 286                          * And here I thought Eazel developers were on crack...
 287                          * if a string is null it should pelt the programmer with
 288                          * ArgumentNullExceptions, damnit!
 289                          */
 290                         if (strA == null) {
 291                                 if (strB == null)
 292                                         return 0;
 293                                 else
 294                                         return -1;
 295                         } else if (strB == null)
 296                                 return 1;
 297
 298                         for (i = 0; strA[i] != '\0' && strB[i] != '\0'; i++) {
 299                                 if (Char.ToLower (strA[i]) != Char.ToLower (strB[i]))
 300                                         break;
 301                         }
 302
 303                         return ((int) (strA[i] - strB[i]));
 304                 }
 305
 306                 public static int Compare (string strA, string strB, bool ignoreCase, CultureInfo culture)
 307                 {
 308                         // FIXME: implement me
 309                         return 0;
 310                 }
 311
 312                 public static int Compare (string strA, int indexA, string strB, int indexB, int length)
 313                 {
 314                         int i;
 315
 316                         if (length < 0 || indexA < 0 || indexB < 0)
 317                                 throw new ArgumentOutOfRangeException ();
 318
 319                         if (indexA > strA.Length || indexB > strB.Length)
 320                                 throw new ArgumentOutOfRangeException ();
 321
 322                         /* And again with the ("" > null) logic... lord have mercy! */
 323                         if (strA == null) {
 324                                 if (strB == null)
 325                                         return 0;
 326                                 else
 327                                         return -1;
 328                         } else if (strB == null)
 329                                 return 1;
 330
 331                         for (i = 0; i < length - 1; i++) {
 332                                 if (strA[indexA + i] != strB[indexB + i])
 333                                         break;
 334                         }
 335
 336                         return ((int) (strA[indexA + i] - strB[indexB + i]));
 337                 }
 338
 339                 public static int Compare (string strA, int indexA, string strB, int indexB,
 340                                            int length, bool ignoreCase)
 341                 {
 342                         int i;
 343
 344                         if (!ignoreCase)
 345                                 return Compare (strA, indexA, strB, indexB, length);
 346
 347                         if (length < 0 || indexA < 0 || indexB < 0)
 348                                 throw new ArgumentOutOfRangeException ();
 349
 350                         if (indexA > strA.Length || indexB > strB.Length)
 351                                 throw new ArgumentOutOfRangeException ();
 352
 353                         /* When will the hurting stop!?!? */
 354                         if (strA == null) {
 355                                 if (strB == null)
 356                                         return 0;
 357                                 else
 358                                         return -1;
 359                         } else if (strB == null)
 360                                 return 1;
 361
 362                         for (i = 0; i < length - 1; i++) {
 363                                 if (Char.ToLower (strA[indexA + i]) != Char.ToLower (strB[indexB + i]))
 364                                         break;
 365                         }
 366
 367                         return ((int) (strA[indexA + i] - strB[indexB + i]));
 368                 }
 369
 370                 public static int Compare (string strA, int indexA, string strB, int indexB,
 371                                            int length, bool ignoreCase, CultureInfo culture)
 372                 {
 373                         if (culture == null)
 374                                 throw new ArgumentNullException ();
 375
 376                         if (length < 0 || indexA < 0 || indexB < 0)
 377                                 throw new ArgumentOutOfRangeException ();
 378
 379                         if (indexA > strA.Length || indexB > strB.Length)
 380                                 throw new ArgumentOutOfRangeException ();
 381
 382                         /* I can't take it anymore! */
 383                         if (strA == null) {
 384                                 if (strB == null)
 385                                         return 0;
 386                                 else
 387                                         return -1;
 388                         } else if (strB == null)
 389                                 return 1;
 390                         // FIXME: implement me
 391                         return 0;
 392                 }
 393
 394                 public static int CompareOrdinal (string strA, string strB)
 395                 {
 396                         int i;
 397
 398                         /* Please God, make it stop! */
 399                         if (strA == null) {
 400                                 if (strB == null)
 401                                         return 0;
 402                                 else
 403                                         return -1;
 404                         } else if (strB == null)
 405                                 return 1;
 406
 407                         for (i = 0; strA[i] != '\0'; i++) {
 408                                 char cA, cB;
 409
 410                                 cA = tolowerordinal (strA[i]);
 411                                 cB = tolowerordinal (strB[i]);
 412
 413                                 if (cA != cB)
 414                                         break;
 415                         }
 416
 417                         return ((int) (strA[i] - strB[i]));
 418                 }
 419
 420                 public static int CompareOrdinal (string strA, int indexA, string strB, int indexB,
 421                                                   int length)
 422                 {
 423                         int i;
 424
 425                         if (length < 0 || indexA < 0 || indexB < 0)
 426                                 throw new ArgumentOutOfRangeException ();
 427
 428                         /* Nooooooooo!! */
 429                         if (strA == null) {
 430                                 if (strB == null)
 431                                         return 0;
 432                                 else
 433                                         return -1;
 434                         } else if (strB == null)
 435                                 return 1;
 436
 437                         for (i = 0; i < length; i++) {
 438                                 char cA, cB;
 439
 440                                 cA = tolowerordinal (strA[indexA + i]);
 441                                 cB = tolowerordinal (strB[indexB + i]);
 442
 443                                 if (cA != cB)
 444                                         break;
 445                         }
 446
 447                         return ((int) (strA[indexA + i] - strB[indexB + i]));
 448                 }
 449
 450                 public int CompareTo (object obj)
 451                 {
 452                         return Compare (this, obj == null ? null : obj.ToString ());
 453                 }
 454
 455                 public int CompareTo (string str)
 456                 {
 457                         return Compare (this, str);
 458                 }
 459
 460                 public static string Concat (object arg)
 461                 {
 462                         return arg != null ? arg.ToString () : String.Empty;
 463                 }
 464
 465                 public static string Concat (params object[] args)
 466                 {
 467                         string[] strings;
 468                         char[] str;
 469                         int len, i;
 470
 471                         if (args == null)
 472                                 throw new ArgumentNullException ();
 473
 474                         strings = new string [args.Length];
 475                         len = 0;
 476                         i = 0;
 477                         foreach (object arg in args) {
 478                                 /* use Empty for each null argument */
 479                                 if (arg == null)
 480                                         strings[i] = String.Empty;
 481                                 else
 482                                         strings[i] = arg.ToString ();
 483                                 len += strings[i].Length;
 484                                 i++;
 485                         }
 486
 487                         if (len == 0)
 488                                 return String.Empty;
 489
 490                         str = new char [len + 1];
 491                         i = 0;
 492                         for (int j = 0; j < strings.Length; j++)
 493                                 for (int k = 0; k < strings[j].Length; k++)
 494                                         str[i++] = strings[j][k];
 495                         str[i] = '\0';
 496
 497                         return new String (str);
 498                 }
 499
 500                 public static string Concat (params string[] values)
 501                 {
 502                         int len, i;
 503                         char[] str;
 504
 505                         if (values == null)
 506                                 throw new ArgumentNullException ();
 507
 508                         len = 0;
 509                         foreach (string value in values)
 510                                 len += value != null ? value.Length : 0;
 511
 512                         if (len == 0)
 513                                 return String.Empty;
 514
 515                         str = new char [len + 1];
 516                         i = 0;
 517                         foreach (string value in values) {
 518                                 if (value == null)
 519                                         continue;
 520
 521                                 for (int j = 0; j < value.Length; j++)
 522                                         str[i++] = value[j];
 523                         }
 524                         str[i] = '\0';
 525
 526                         return new String (str);
 527                 }
 528
 529                 public static string Concat (object arg0, object arg1)
 530                 {
 531                         string str0 = arg0 != null ? arg0.ToString () : String.Empty;
 532                         string str1 = arg1 != null ? arg1.ToString () : String.Empty;
 533
 534                         return Concat (str0, str1);
 535                 }
 536
 537                 public static string Concat (string str0, string str1)
 538                 {
 539                         char[] concat;
 540                         int i, j, len;
 541
 542                         if (str0 == null)
 543                                 str0 = String.Empty;
 544                         if (str1 == null)
 545                                 str1 = String.Empty;
 546
 547                         len = str0.Length + str1.Length;
 548                         if (len == 0)
 549                                 return String.Empty;
 550
 551                         concat = new char [len + 1];
 552                         for (i = 0; i < str0.Length; i++)
 553                                 concat[i] = str0[i];
 554                         for (j = 0 ; j < str1.Length; j++)
 555                                 concat[i + j] = str1[j];
 556                         concat[len] = '\0';
 557
 558                         return new String (concat);
 559                 }
 560
 561                 public static string Concat (object arg0, object arg1, object arg2)
 562                 {
 563                         string str0 = arg0 != null ? arg0.ToString () : String.Empty;
 564                         string str1 = arg1 != null ? arg1.ToString () : String.Empty;
 565                         string str2 = arg2 != null ? arg2.ToString () : String.Empty;
 566
 567                         return Concat (str0, str1, str2);
 568                 }
 569
 570                 public static string Concat (string str0, string str1, string str2)
 571                 {
 572                         char[] concat;
 573                         int i, j, k, len;
 574
 575                         if (str0 == null)
 576                                 str0 = String.Empty;
 577                         if (str1 == null)
 578                                 str1 = String.Empty;
 579                         if (str2 == null)
 580                                 str2 = String.Empty;
 581
 582                         len = str0.Length + str1.Length + str2.Length;
 583                         if (len == 0)
 584                                 return String.Empty;
 585
 586                         concat = new char [len + 1];
 587                         for (i = 0; i < str0.Length; i++)
 588                                 concat[i] = str0[i];
 589                         for (j = 0; j < str1.Length; j++)
 590                                 concat[i + j] = str1[j];
 591                         for (k = 0; k < str2.Length; k++)
 592                                 concat[i + j + k] = str2[k];
 593                         concat[len] = '\0';
 594
 595                         return new String (concat);
 596                 }
 597
 598                 public static string Concat (string str0, string str1, string str2, string str3)
 599                 {
 600                         char[] concat;
 601                         int i, j, k, l, len;
 602
 603                         if (str0 == null)
 604                                 str0 = String.Empty;
 605                         if (str1 == null)
 606                                 str1 = String.Empty;
 607                         if (str2 == null)
 608                                 str2 = String.Empty;
 609                         if (str3 == null)
 610                                 str3 = String.Empty;
 611
 612                         len = str0.Length + str1.Length + str2.Length + str3.Length;
 613                         if (len == 0)
 614                                 return String.Empty;
 615
 616                         concat = new char [len + 1];
 617                         for (i = 0; i < str0.Length; i++)
 618                                 concat[i] = str0[i];
 619                         for (j = 0; j < str1.Length; j++)
 620                                 concat[i + j] = str1[j];
 621                         for (k = 0; k < str2.Length; k++)
 622                                 concat[i + j + k] = str2[k];
 623                         for (l = 0; l < str3.Length; l++)
 624                                 concat[i + j + k + l] = str3[l];
 625                         concat[len] = '\0';
 626
 627                         return new String (concat);
 628                 }
 629
 630                 public static string Copy (string str)
 631                 {
 632                         // FIXME: how do I *copy* a string if I can only have 1 of each?
 633                         if (str == null)
 634                                 throw new ArgumentNullException ();
 635
 636                         return str;
 637                 }
 638
 639                 public void CopyTo (int sourceIndex, char[] destination, int destinationIndex, int count)
 640                 {
 641                         // LAMESPEC: should I null-terminate?
 642                         int i;
 643
 644                         if (destination == null)
 645                                 throw new ArgumentNullException ();
 646
 647                         if (sourceIndex < 0 || destinationIndex < 0 || count < 0)
 648                                 throw new ArgumentOutOfRangeException ();
 649
 650                         if (sourceIndex + count > this.length)
 651                                 throw new ArgumentOutOfRangeException ();
 652
 653                         if (destinationIndex + count > destination.Length)
 654                                 throw new ArgumentOutOfRangeException ();
 655
 656                         for (i = 0; i < count; i++)
 657                                 destination[destinationIndex + i] = this.c_str[sourceIndex + i];
 658                 }
 659
 660                 public bool EndsWith (string value)
 661                 {
 662                         bool endswith = true;
 663                         int start, i;
 664
 665                         if (value == null)
 666                                 throw new ArgumentNullException ();
 667
 668                         start = this.length - value.Length;
 669                         if (start < 0)
 670                                 return false;
 671
 672                         for (i = start; i < this.length && endswith; i++)
 673                                 endswith = this.c_str[i] == value[i - start];
 674
 675                         return endswith;
 676                 }
 677
 678                 public override bool Equals (object obj)
 679                 {
 680                         if (!(obj is String))
 681                                 return false;
 682
 683                         return this == (String) obj;
 684                 }
 685
 686                 public bool Equals (string value)
 687                 {
 688                         return this == value;
 689                 }
 690
 691                 public static bool Equals (string a, string b)
 692                 {
 693                         return a == b;
 694                 }
 695
 696                 public static string Format (string format, object arg0)
 697                 {
 698                         // FIXME: implement me
 699                         return null;
 700                 }
 701
 702                 public static string Format (string format, params object[] args)
 703                 {
 704                         // FIXME: implement me
 705                         return null;
 706                 }
 707
 708                 public static string Format (IFormatProvider provider, string format, params object[] args)
 709                 {
 710                         // FIXME: implement me
 711                         return null;
 712                 }
 713
 714                 public static string Format (string format, object arg0, object arg1)
 715                 {
 716                         // FIXME: implement me
 717                         return null;
 718                 }
 719
 720                 public static string Format (string format, object arg0, object arg1, object arg2)
 721                 {
 722                         // FIXME: implement me
 723                         return null;
 724                 }
 725
 726                 //public CharEnumerator GetEnumerator ()
 727                 public IEnumerator GetEnumerator ()
 728                 {
 729                         // FIXME: implement me
 730                         return null;
 731                 }
 732
 733                 public override int GetHashCode ()
 734                 {
 735                         // FIXME: implement me
 736                         return 0;
 737                 }
 738
 739                 public new Type GetType ()
 740                 {
 741                         // FIXME: implement me
 742                         return null;
 743                 }
 744
 745                 public TypeCode GetTypeCode ()
 746                 {
 747                         // FIXME: implement me
 748                         return 0;
 749                 }
 750
 751                 public int IndexOf (char value)
 752                 {
 753                         return IndexOf (value, 0, this.length);
 754                 }
 755
 756                 public int IndexOf (string value)
 757                 {
 758                         return IndexOf (value, 0, this.length);
 759                 }
 760
 761                 public int IndexOf (char value, int startIndex)
 762                 {
 763                         return IndexOf (value, startIndex, this.length - startIndex);
 764                 }
 765
 766                 public int IndexOf (string value, int startIndex)
 767                 {
 768                         return IndexOf (value, startIndex, this.length - startIndex);
 769                 }
 770
 771                 public int IndexOf (char value, int startIndex, int count)
 772                 {
 773                         int i;
 774
 775                         if (startIndex < 0 || count < 0 || startIndex + count > this.length)
 776                                 throw new ArgumentOutOfRangeException ();
 777
 778                         for (i = startIndex; i - startIndex < count; i++)
 779                                 if (this.c_str[i] == value)
 780                                         return i;
 781
 782                         return -1;
 783                 }
 784
 785                 public int IndexOf (string value, int startIndex, int count)
 786                 {
 787                         int i;
 788
 789                         if (value == null)
 790                                 throw new ArgumentNullException ();
 791
 792                         if (startIndex < 0 || count < 0 || startIndex + count > this.length)
 793                                 throw new ArgumentOutOfRangeException ();
 794
 795                         return BoyerMoore (this.c_str, value, startIndex, count);
 796 #if XXX
 797                         for (i = startIndex; i - startIndex + value.Length <= count; ) {
 798                                 if (this.c_str[i] == value[0]) {
 799                                         bool equal = true;
 800                                         int j, nexti = 0;
 801
 802                                         for (j = 1; equal && value[j] != '\0'; j++) {
 803                                                 equal = this.c_str[i + j] == value[j];
 804                                                 if (this.c_str[i + j] == value[0] && nexti == 0)
 805                                                         nexti = i + j;
 806                                         }
 807
 808                                         if (equal)
 809                                                 return i;
 810
 811                                         if (nexti != 0)
 812                                                 i = nexti;
 813                                         else
 814                                                 i += j;
 815                                 } else
 816                                         i++;
 817                         }
 818
 819                         return -1;
 820 #endif
 821                 }
 822
 823                 public int IndexOfAny (char[] values)
 824                 {
 825                         return IndexOfAny (values, 0, this.length);
 826                 }
 827
 828                 public int IndexOfAny (char[] values, int startIndex)
 829                 {
 830                         return IndexOfAny (values, startIndex, this.length - startIndex);
 831                 }
 832
 833                 public int IndexOfAny (char[] values, int startIndex, int count)
 834                 {
 835                         if (values == null)
 836                                 throw new ArgumentNullException ();
 837
 838                         if (startIndex < 0 || count < 0 || startIndex + count > this.length)
 839                                 throw new ArgumentOutOfRangeException ();
 840
 841                         for (int i = startIndex; i < startIndex + count; i++) {
 842                                 for (int j = 0; j < strlen (values); j++) {
 843                                         if (this.c_str[i] == values[j])
 844                                                 return i;
 845                                 }
 846                         }
 847
 848                         return -1;
 849                 }
 850
 851                 public string Insert (int startIndex, string value)
 852                 {
 853                         char[] str;
 854                         int i, j;
 855
 856                         if (value == null)
 857                                 throw new ArgumentNullException ();
 858
 859                         if (startIndex < 0 || startIndex > this.length)
 860                                 throw new ArgumentOutOfRangeException ();
 861
 862                         str = new char [value.Length + this.length + 1];
 863                         for (i = 0; i < startIndex; i++)
 864                                 str[i] = this.c_str[i];
 865                         for (j = 0; j < value.Length; j++)
 866                                 str[i + j] = value[j];
 867                         for ( ; i < this.length; i++)
 868                                 str[i + j] = this.c_str[i];
 869                         str[i + j] = '\0';
 870
 871                         return new String (str);
 872                 }
 873
 874                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
 875                 public extern static string Intern (string str);
 876
 877                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
 878                 public extern static string IsInterned (string str);
 879
 880                 public static string Join (string separator, string[] value)
 881                 {
 882                         return Join (separator, value, 0, value.Length);
 883                 }
 884
 885                 public static string Join (string separator, string[] value, int startIndex, int count)
 886                 {
 887                         // LAMESPEC: msdn doesn't specify what happens when separator is null
 888                         int len, i, j, used;
 889                         char[] str;
 890
 891                         if (separator == null || value == null)
 892                                 throw new ArgumentNullException ();
 893
 894                         if (startIndex + count > value.Length)
 895                                 throw new ArgumentOutOfRangeException ();
 896
 897                         len = 0;
 898                         for (i = startIndex, used = 0; used < count; i++, used++) {
 899                                 if (i != startIndex)
 900                                         len += separator.Length;
 901
 902                                 len += value[i].Length;
 903                         }
 904
 905                         // We have no elements to join?
 906                         if (i == startIndex)
 907                                 return String.Empty;
 908
 909                         str = new char [len + 1];
 910                         for (i = 0; i < value[startIndex].Length; i++)
 911                                 str[i] = value[startIndex][i];
 912
 913                         used = 1;
 914                         for (j = startIndex + 1; used < count; j++, used++) {
 915                                 int k;
 916
 917                                 for (k = 0; k < separator.Length; k++)
 918                                         str[i++] = separator[k];
 919                                 for (k = 0; k < value[j].Length; k++)
 920                                         str[i++] = value[j][k];
 921                         }
 922                         str[i] = '\0';
 923
 924                         return new String (str);
 925                 }
 926
 927                 public int LastIndexOf (char value)
 928                 {
 929                         for (int i = this.length; i >= 0; i--) {
 930                                 if (this.c_str[i] == value)
 931                                         return i;
 932                         }
 933
 934                         return -1;
 935                 }
 936
 937                 public int LastIndexOf (string value)
 938                 {
 939                         return LastIndexOf (value, this.length, this.length);
 940                 }
 941
 942                 public int LastIndexOf (char value, int startIndex)
 943                 {
 944                         if (startIndex < 0 || startIndex > this.length)
 945                                 throw new ArgumentOutOfRangeException ();
 946
 947                         for (int i = startIndex; i >= 0; i--) {
 948                                 if (this.c_str[i] == value)
 949                                         return i;
 950                         }
 951
 952                         return -1;
 953                 }
 954
 955                 public int LastIndexOf (string value, int startIndex)
 956                 {
 957                         return LastIndexOf (value, startIndex, this.length);
 958                 }
 959
 960                 public int LastIndexOf (char value, int startIndex, int count)
 961                 {
 962                         if (startIndex < 0 || count < 0)
 963                                 throw new ArgumentOutOfRangeException ();
 964
 965                         if (startIndex > this.length || startIndex - count < 0)
 966                                 throw new ArgumentOutOfRangeException ();
 967
 968                         for (int i = startIndex; i >= startIndex - count; i--) {
 969                                 if (this.c_str[i] == value)
 970                                         return i;
 971                         }
 972
 973                         return -1;
 974                 }
 975
 976                 public int LastIndexOf (string value, int startIndex, int count)
 977                 {
 978                         // LAMESPEC: currently I'm using startIndex as the 0-position in the comparison,
 979                         //           but maybe it's the end-position in MS's implementation?
 980                         //           msdn is unclear on this point. I think this is correct though.
 981                         int i, len;
 982
 983                         if (value == null)
 984                                 throw new ArgumentNullException ();
 985
 986                         if (startIndex < 0 || startIndex > this.length)
 987                                 throw new ArgumentOutOfRangeException ();
 988
 989                         if (count < 0 || startIndex - count < 0)
 990                                 throw new ArgumentOutOfRangeException ();
 991
 992                         if (value == String.Empty)
 993                                 return startIndex;
 994
 995                         if (startIndex + value.Length > this.length) {
 996                                 /* just a little optimization */
 997                                 int start;
 998
 999                                 start = this.length - value.Length;
1000                                 count -= startIndex - start;
1001                                 startIndex = start;
1002                         }
1003
1004                         // FIXME: use a reversed-unicode-safe-Boyer-Moore?
1005                         len = value.Length - 1;
1006                         for (i = startIndex; i >= startIndex - count; i--) {
1007                                 if (this.c_str[i + len] == value[len]) {
1008                                         bool equal = true;
1009                                         int j;
1010
1011                                         for (j = len - 1; equal && j >= 0; j--)
1012                                                 equal = this.c_str[i + j] == value[j];
1013
1014                                         if (equal)
1015                                                 return i;
1016                                 }
1017                         }
1018
1019                         return -1;
1020                 }
1021
1022                 public int LastIndexOfAny (char[] values)
1023                 {
1024                         return LastIndexOfAny (values, this.length, this.length);
1025                 }
1026
1027                 public int LastIndexOfAny (char[] values, int startIndex)
1028                 {
1029                         return LastIndexOfAny (values, startIndex, startIndex);
1030                 }
1031
1032                 public int LastIndexOfAny (char[] values, int startIndex, int count)
1033                 {
1034                         int i;
1035
1036                         if (values == null)
1037                                 throw new ArgumentNullException ();
1038
1039                         if (startIndex < 0 || count < 0 || startIndex - count < 0)
1040                                 throw new ArgumentOutOfRangeException ();
1041
1042                         for (i = startIndex; i >= startIndex - count; i--) {
1043                                 for (int j = 0; j < strlen (values); j++) {
1044                                         if (this.c_str[i] == values[j])
1045                                                 return i;
1046                                 }
1047                         }
1048
1049                         return -1;
1050                 }
1051
1052                 public string PadLeft (int totalWidth)
1053                 {
1054                         return PadLeft (totalWidth, ' ');
1055                 }
1056
1057                 public string PadLeft (int totalWidth, char padChar)
1058                 {
1059                         char[] str;
1060                         int i, j;
1061
1062                         if (totalWidth < 0)
1063                                 throw new ArgumentException ();
1064
1065                         str = new char [totalWidth > this.length ? totalWidth : this.length + 1];
1066                         for (i = 0; i < totalWidth - this.length; i++)
1067                                 str[i] = padChar;
1068
1069                         for (j = 0; j < this.length; i++, j++)
1070                                 str[i] = this.c_str[j];
1071
1072                         str[i] = '\0';
1073
1074                         return new String (str);
1075                 }
1076
1077                 public string PadRight (int totalWidth)
1078                 {
1079                         return PadRight (totalWidth, ' ');
1080                 }
1081
1082                 public string PadRight (int totalWidth, char padChar)
1083                 {
1084                         char[] str;
1085                         int i;
1086
1087                         if (totalWidth < 0)
1088                                 throw new ArgumentException ();
1089
1090                         str = new char [totalWidth > this.length ? totalWidth : this.length + 1];
1091                         for (i = 0; i < this.length; i++)
1092                                 str[i] = this.c_str[i];
1093
1094                         for ( ; i < str.Length; i++)
1095                                 str[i] = padChar;
1096
1097                         str[i] = '\0';
1098
1099                         return new String (str);
1100                 }
1101
1102                 public string Remove (int startIndex, int count)
1103                 {
1104                         char[] str;
1105                         int i, j, len;
1106
1107                         if (startIndex < 0 || count < 0 || startIndex + count > this.length)
1108                                 throw new ArgumentOutOfRangeException ();
1109
1110                         len = this.length - count;
1111                         if (len == 0)
1112                                 return String.Empty;
1113
1114                         str = new char [len + 1];
1115                         for (i = 0; i < startIndex; i++)
1116                                 str[i] = this.c_str[i];
1117                         for (j = i + count; j < this.length; j++)
1118                                 str[i++] = this.c_str[j];
1119                         str[i] = '\0';
1120
1121                         return new String (str);
1122                 }
1123
1124                 public string Replace (char oldChar, char newChar)
1125                 {
1126                         char[] str;
1127                         int i;
1128
1129                         str = new char [this.length + 1];
1130                         for (i = 0; i < this.length; i++) {
1131                                 if (this.c_str[i] == oldChar)
1132                                         str[i] = newChar;
1133                                 else
1134                                         str[i] = this.c_str[i];
1135                         }
1136                         str[i] = '\0';
1137
1138                         return new String (str);
1139                 }
1140
1141                 public string Replace (string oldValue, string newValue)
1142                 {
1143                         // LAMESPEC: msdn doesn't specify what to do if either args is null
1144                         int index, len, i, j;
1145                         char[] str;
1146
1147                         if (oldValue == null || newValue == null)
1148                                 throw new ArgumentNullException ();
1149
1150                         // Use IndexOf in case I later rewrite it to use Boyer-Moore
1151                         index = IndexOf (oldValue, 0);
1152                         if (index == -1) {
1153                                 // This is the easy one ;-)
1154                                 return Substring (0, this.length);
1155                         }
1156
1157                         len = this.length - oldValue.Length + newValue.Length;
1158                         if (len == 0)
1159                                 return String.Empty;
1160
1161                         str = new char [len + 1];
1162                         for (i = 0; i < index; i++)
1163                                 str[i] = this.c_str[i];
1164                         for (j = 0; j < newValue.Length; j++)
1165                                 str[i++] = newValue[j];
1166                         for (j = index + oldValue.Length; j < this.length; j++)
1167                                 str[i++] = this.c_str[j];
1168                         str[i] = '\0';
1169
1170                         return new String (str);
1171                 }
1172
1173                 private int splitme (char[] separators, int startIndex)
1174                 {
1175                         /* this is basically a customized IndexOfAny() for the Split() methods */
1176                         for (int i = startIndex; i < this.length; i++) {
1177                                 if (separators != null) {
1178                                         foreach (char sep in separators) {
1179                                                 if (this.c_str[i] == sep)
1180                                                         return i - startIndex;
1181                                         }
1182                                 } else if (is_lwsp (this.c_str[i])) {
1183                                         return i - startIndex;
1184                                 }
1185                         }
1186
1187                         return -1;
1188                 }
1189
1190                 public string[] Split (params char[] separator)
1191                 {
1192                         /**
1193                          * split:
1194                          * @separator: delimiting chars or null to split on whtspc
1195                          *
1196                          * Returns: 1. An array consisting of a single
1197                          * element (@this) if none of the delimiting
1198                          * chars appear in @this. 2. An array of
1199                          * substrings which are delimited by one of
1200                          * the separator chars. 3. An array of
1201                          * substrings separated by whitespace if
1202                          * @separator is null. The Empty string should
1203                          * be returned wherever 2 delimiting chars are
1204                          * adjacent.
1205                          **/
1206                         // FIXME: would using a Queue be better?
1207                         string[] strings;
1208                         ArrayList list;
1209                         int index, len;
1210
1211                         list = new ArrayList ();
1212                         for (index = 0, len = 0; index < this.length; index += len + 1) {
1213                                 len = splitme (separator, index);
1214                                 len = len > -1 ? len : this.length - index;
1215                                 if (len == 0) {
1216                                         list.Add (String.Empty);
1217                                 } else {
1218                                         char[] str;
1219                                         int i;
1220
1221                                         str = new char [len + 1];
1222                                         for (i = 0; i < len; i++)
1223                                                 str[i] = this.c_str[index + i];
1224                                         str[i] = '\0';
1225
1226                                         list.Add (new String (str));
1227                                 }
1228                         }
1229
1230                         strings = new string [list.Count];
1231                         if (list.Count == 1) {
1232                                 /* special case for an array holding @this */
1233                                 strings[0] = this;
1234                         } else {
1235                                 for (index = 0; index < list.Count; index++)
1236                                         strings[index] = (string) list[index];
1237                         }
1238
1239                         return strings;
1240                 }
1241
1242                 public string[] Split (char[] separator, int maxCount)
1243                 {
1244                         // FIXME: what to do if maxCount <= 0?
1245                         // FIXME: would using Queue be better than ArrayList?
1246                         string[] strings;
1247                         ArrayList list;
1248                         int index, len, used;
1249
1250                         used = 0;
1251                         list = new ArrayList ();
1252                         for (index = 0, len = 0; index < this.length && used < maxCount; index += len + 1) {
1253                                 len = splitme (separator, index);
1254                                 len = len > -1 ? len : this.length - index;
1255                                 if (len == 0) {
1256                                         list.Add (String.Empty);
1257                                 } else {
1258                                         char[] str;
1259                                         int i;
1260
1261                                         str = new char [len + 1];
1262                                         for (i = 0; i < len; i++)
1263                                                 str[i] = this.c_str[index + i];
1264                                         str[i] = '\0';
1265
1266                                         list.Add (new String (str));
1267                                 }
1268                                 used++;
1269                         }
1270
1271                         /* fit the remaining chunk of the @this into it's own element */
1272                         if (index != this.length) {
1273                                 char[] str;
1274                                 int i;
1275
1276                                 str = new char [this.length - index + 1];
1277                                 for (i = index; i < this.length; i++)
1278                                         str[i - index] = this.c_str[i];
1279                                 str[i - index] = '\0';
1280
1281                                 list.Add (new String (str));
1282                         }
1283
1284                         strings = new string [list.Count];
1285                         if (list.Count == 1) {
1286                                 /* special case for an array holding @this */
1287                                 strings[0] = this;
1288                         } else {
1289                                 for (index = 0; index < list.Count; index++)
1290                                         strings[index] = (string) list[index];
1291                         }
1292
1293                         return strings;
1294                 }
1295
1296                 public bool StartsWith (string value)
1297                 {
1298                         bool startswith = true;
1299                         int i;
1300
1301                         if (value == null)
1302                                 throw new ArgumentNullException ();
1303
1304                         if (value.Length > this.length)
1305                                 return false;
1306
1307                         for (i = 0; i < value.Length && startswith; i++)
1308                                 startswith = startswith && value[i] == this.c_str[i];
1309
1310                         return startswith;
1311                 }
1312
1313                 public string Substring (int startIndex)
1314                 {
1315                         char[] str;
1316                         int i, len;
1317
1318                         if (startIndex < 0 || startIndex > this.length)
1319                                 throw new ArgumentOutOfRangeException ();
1320
1321                         len = this.length - startIndex;
1322                         if (len == 0)
1323                                 return String.Empty;
1324
1325                         str = new char [len + 1];
1326                         for (i = startIndex; i < this.length; i++)
1327                                 str[i - startIndex] = this.c_str[i];
1328                         str[i] = '\0';
1329
1330                         return new String (str);
1331                 }
1332
1333                 public string Substring (int startIndex, int length)
1334                 {
1335                         char[] str;
1336                         int i;
1337
1338                         if (startIndex < 0 || length < 0 || startIndex + length > this.length)
1339                                 throw new ArgumentOutOfRangeException ();
1340
1341                         if (length == 0)
1342                                 return String.Empty;
1343
1344                         str = new char [length + 1];
1345                         for (i = startIndex; i < startIndex + length; i++)
1346                                 str[i - startIndex] = this.c_str[i];
1347                         str[i] = '\0';
1348
1349                         return new String (str);
1350                 }
1351
1352                 public bool ToBoolean (IFormatProvider provider)
1353                 {
1354                         // FIXME: implement me
1355                         return false;
1356                 }
1357
1358                 public byte ToByte (IFormatProvider provider)
1359                 {
1360                         // FIXME: implement me
1361                         return (byte) '\0';
1362                 }
1363
1364                 public char ToChar (IFormatProvider provider)
1365                 {
1366                         // FIXME: implement me
1367                         return '\0';
1368                 }
1369
1370                 public char[] ToCharArray ()
1371                 {
1372                         return ToCharArray (0, this.length);
1373                 }
1374
1375                 public char[] ToCharArray (int startIndex, int length)
1376                 {
1377                         char[] chars;
1378                         int i;
1379
1380                         if (startIndex < 0 || length < 0 || startIndex + length > this.length)
1381                                 throw new ArgumentOutOfRangeException ();
1382
1383                         chars = new char [length + 1];
1384                         for (i = startIndex; i < length; i++)
1385                                 chars[i - startIndex] = this.c_str[i];
1386
1387                         chars[length] = '\0';
1388
1389                         return chars;
1390                 }
1391
1392                 public DateTime ToDateTime (IFormatProvider provider)
1393                 {
1394                         // FIXME: implement me
1395
1396                         return new DateTime (0);
1397                 }
1398
1399                 public decimal ToDecimal (IFormatProvider provider)
1400                 {
1401                         // FIXME: implement me
1402                         return 0.0M;
1403                 }
1404
1405                 public double ToDouble (IFormatProvider provider)
1406                 {
1407                         // FIXME: implement me
1408                         return 0.0;
1409                 }
1410
1411                 public short ToInt16 (IFormatProvider provider)
1412                 {
1413                         // FIXME: implement me
1414                         return 0;
1415                 }
1416
1417                 public int ToInt32 (IFormatProvider provider)
1418                 {
1419                         // FIXME: implement me
1420                         return 0;
1421                 }
1422
1423                 public long ToInt64 (IFormatProvider provider)
1424                 {
1425                         // FIXME: implement me
1426                         return 0;
1427                 }
1428
1429                 public string ToLower ()
1430                 {
1431                         char[] str;
1432                         int i;
1433
1434                         str = new char [this.length + 1];
1435                         for (i = 0; i < this.length; i++)
1436                                 str[i] = Char.ToLower (this.c_str[i]);
1437                         str[i] = '\0';
1438
1439                         return new String (str);
1440                 }
1441
1442                 public string ToLower (CultureInfo culture)
1443                 {
1444                         // FIXME: implement me
1445                         return null;
1446                 }
1447
1448                 public sbyte ToSByte (IFormatProvider provider)
1449                 {
1450                         // FIXME: implement me
1451                         return 0;
1452                 }
1453
1454                 public float ToSingle (IFormatProvider provider)
1455                 {
1456                         // FIXME: implement me
1457                         return 0.0F;
1458                 }
1459
1460                 public override string ToString ()
1461                 {
1462                         return Substring (0, this.length);
1463                 }
1464
1465                 public string ToString (IFormatProvider format)
1466                 {
1467                         // FIXME: implement me
1468                         return null;
1469                 }
1470
1471                 public object ToType (Type conversionType, IFormatProvider provider)
1472                 {
1473                         // FIXME: implement me
1474                         return null;
1475                 }
1476
1477                 public ushort ToUInt16 (IFormatProvider provider)
1478                 {
1479                         // FIXME: implement me
1480                         return 0;
1481                 }
1482
1483                 public uint ToUInt32 (IFormatProvider provider)
1484                 {
1485                         // FIXME: implement me
1486                         return 0;
1487                 }
1488
1489                 public ulong ToUInt64 (IFormatProvider provider)
1490                 {
1491                         // FIXME: implement me
1492                         return 0;
1493                 }
1494
1495                 public string ToUpper ()
1496                 {
1497                         char[] str;
1498                         int i;
1499
1500                         str = new char [this.length + 1];
1501                         for (i = 0; i < this.length; i++)
1502                                 str[i] = Char.ToUpper (this.c_str[i]);
1503                         str[i] = '\0';
1504
1505                         return new String (str);
1506                 }
1507
1508                 public string ToUpper (CultureInfo culture)
1509                 {
1510                         // FIXME: implement me
1511                         return null;
1512                 }
1513
1514                 public string Trim ()
1515                 {
1516                         return Trim (null);
1517                 }
1518
1519                 public string Trim (params char[] trimChars)
1520                 {
1521                         int begin, end;
1522                         bool matches;
1523
1524                         matches = true;
1525                         for (begin = 0; matches && begin < this.length; begin++) {
1526                                 if (trimChars != null) {
1527                                         matches = false;
1528                                         foreach (char c in trimChars) {
1529                                                 matches = this.c_str[begin] == c;
1530                                                 if (matches)
1531                                                         break;
1532                                         }
1533                                 } else {
1534                                         matches = is_lwsp (this.c_str[begin]);
1535                                 }
1536                         }
1537
1538                         matches = true;
1539                         for (end = this.length; end > begin; end--) {
1540                                 if (trimChars != null) {
1541                                         matches = false;
1542                                         foreach (char c in trimChars) {
1543                                                 matches = this.c_str[end] == c;
1544                                                 if (matches)
1545                                                         break;
1546                                         }
1547                                 } else {
1548                                         matches = is_lwsp (this.c_str[end]);
1549                                 }
1550                         }
1551
1552                         if (begin == end)
1553                                 return String.Empty;
1554
1555                         return Substring (begin, end - begin);
1556                 }
1557
1558                 public string TrimEnd (params char[] trimChars)
1559                 {
1560                         bool matches = true;
1561                         int end;
1562
1563                         for (end = this.length; end > 0; end--) {
1564                                 if (trimChars != null) {
1565                                         matches = false;
1566                                         foreach (char c in trimChars) {
1567                                                 matches = this.c_str[end] == c;
1568                                                 if (matches)
1569                                                         break;
1570                                         }
1571                                 } else {
1572                                         matches = is_lwsp (this.c_str[end]);
1573                                 }
1574                         }
1575
1576                         if (end == 0)
1577                                 return String.Empty;
1578
1579                         return Substring (0, end);
1580                 }
1581
1582                 public string TrimStart (params char[] trimChars)
1583                 {
1584                         bool matches = true;
1585                         int begin;
1586
1587                         for (begin = 0; matches && begin < this.length; begin++) {
1588                                 if (trimChars != null) {
1589                                         matches = false;
1590                                         foreach (char c in trimChars) {
1591                                                 matches = this.c_str[begin] == c;
1592                                                 if (matches)
1593                                                         break;
1594                                         }
1595                                 } else {
1596                                         matches = is_lwsp (this.c_str[begin]);
1597                                 }
1598                         }
1599
1600                         if (begin == this.length)
1601                                 return String.Empty;
1602
1603                         return Substring (begin, this.length - begin);
1604                 }
1605
1606                 // Operators
1607                 public static bool operator ==(string a, string b)
1608                 {
1609                         if (a.length != b.length)
1610                                 return false;
1611
1612                         int l = a.length;
1613                         for (int i = 0; i < l; i++)
1614                                 if (a.c_str [i] != b.c_str [i])
1615                                         return false;
1616
1617                         return true;
1618                 }
1619
1620                 public static bool operator !=(string a, string b)
1621                 {
1622                         return !(a == b);
1623                 }
1624         }
1625 }