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         //[DefaultMemberName("Chars")]
  33         public sealed class String : IComparable, ICloneable, IConvertible, IEnumerable {
  34                 public static readonly string Empty = "";
  35                 private char[] c_str;
  36                 private int length;
  37
  38                 // Constructors
  39
  40                 internal String (int storage)
  41                 {
  42                         length = storage;
  43                         c_str = new char [storage];
  44                 }
  45
  46                 [CLSCompliant(false)]
  47                 unsafe public String (char *value)
  48                 {
  49                         int i;
  50
  51                         // FIXME: can I do value.Length here?
  52                         if (value == null) {
  53                                 this.length = 0;
  54                         } else {
  55                                 for (i = 0; *(value + i) != '\0'; i++);
  56                                 this.length = i;
  57                         }
  58
  59                         this.c_str = new char [this.length + 1];
  60                         for (i = 0; i < this.length; i++)
  61                                 this.c_str[i] = *(value + i);
  62                 }
  63
  64                 public String (char[] value)
  65                 {
  66                         int i;
  67
  68                         // FIXME: value.Length includes the terminating null char?
  69                         this.length = value != null ? strlen (value): 0;
  70                         this.c_str = new char [this.length + 1];
  71                         for (i = 0; i < this.length; i++)
  72                                 this.c_str[i] = value[i];
  73                 }
  74
  75                 [CLSCompliant(false)]
  76                 unsafe public String (sbyte *value)
  77                 {
  78                         // FIXME: consider unicode?
  79                         int i;
  80
  81                         // FIXME: can I do value.Length here? */
  82                         if (value == null) {
  83                                 this.length = 0;
  84                         } else {
  85                                 for (i = 0; *(value + i) != '\0'; i++);
  86                                 this.length = i;
  87                         }
  88
  89                         this.c_str = new char [this.length + 1];
  90                         for (i = 0; i < this.length; i++)
  91                                 this.c_str[i] = (char) *(value + i);
  92                 }
  93
  94                 public String (char c, int count)
  95                 {
  96                         int i;
  97
  98                         this.length = count;
  99                         this.c_str = new char [count + 1];
 100                         for (i = 0; i < count; i++)
 101                                 this.c_str[i] = c;
 102                 }
 103
 104                 [CLSCompliant(false)]
 105                 unsafe public String (char *value, int startIndex, int length)
 106                 {
 107                         int i;
 108
 109                         if (value == null && startIndex != 0 && length != 0)
 110                                 throw new ArgumentNullException ();
 111
 112                         if (startIndex < 0 || length < 0)
 113                                 throw new ArgumentOutOfRangeException ();
 114
 115                         this.length = length;
 116                         this.c_str = new char [length + 1];
 117                         for (i = 0; i < length; i++)
 118                                 this.c_str[i] = *(value + startIndex + i);
 119                 }
 120
 121                 public String (char[] value, int startIndex, int length)
 122                 {
 123                         int i;
 124
 125                         if (value == null && startIndex != 0 && length != 0)
 126                                 throw new ArgumentNullException ();
 127
 128                         if (startIndex < 0 || length < 0)
 129                                 throw new ArgumentOutOfRangeException ();
 130
 131                         this.length = length;
 132                         this.c_str = new char [length + 1];
 133                         for (i = 0; i < length; i++)
 134                                 this.c_str[i] = value[startIndex + i];
 135                 }
 136
 137                 [CLSCompliant(false)]
 138                 unsafe public String (sbyte *value, int startIndex, int length)
 139                 {
 140                         // FIXME: consider unicode?
 141                         int i;
 142
 143                         if (value == null && startIndex != 0 && length != 0)
 144                                 throw new ArgumentNullException ();
 145
 146                         if (startIndex < 0 || length < 0)
 147                                 throw new ArgumentOutOfRangeException ();
 148
 149                         this.length = length;
 150                         this.c_str = new char [length + 1];
 151                         for (i = 0; i < length; i++)
 152                                 this.c_str[i] = (char) *(value + startIndex + i);
 153                 }
 154
 155                 [CLSCompliant(false)][MonoTODO]
 156                 unsafe public String (sbyte *value, int startIndex, int length, Encoding enc)
 157                 {
 158                         // FIXME: implement me
 159                 }
 160
 161                 ~String ()
 162                 {
 163                         // FIXME: is there anything we need to do here?
 164                         /*base.Finalize ();*/
 165                 }
 166
 167                 // Properties
 168                 public int Length {
 169                         get {
 170                                 return this.length;
 171                         }
 172                 }
 173
 174                 [IndexerName("Chars")]
 175                 public char this [int index] {
 176                         get {
 177                                 if (index >= this.length)
 178                                         throw new ArgumentOutOfRangeException ();
 179
 180                                 return this.c_str[index];
 181                         }
 182                 }
 183
 184                 // Private helper methods
 185                 private static int strlen (char[] str)
 186                 {
 187                         // FIXME: if str.Length includes terminating null char, then return (str.Length - 1)
 188                         return str.Length;
 189                 }
 190
 191                 [MonoTODO]
 192                 private static char tolowerordinal (char c)
 193                 {
 194                         // FIXME: implement me
 195                         return c;
 196                 }
 197
 198                 private static bool is_lwsp (char c)
 199                 {
 200                         /* this comes from the msdn docs for String.Trim() */
 201                         if ((c >= '\x9' && c <= '\xD') || c == '\x20' || c == '\xA0' ||
 202                             (c >= '\x2000' && c <= '\x200B') || c == '\x3000' || c == '\xFEFF')
 203                                 return true;
 204                         else
 205                                 return false;
 206                 }
 207
 208                 private static int BoyerMoore (char[] haystack, string needle, int startIndex, int count)
 209                 {
 210                         /* (hopefully) Unicode-safe Boyer-Moore implementation */
 211                         int[] skiptable = new int[65536];  /* our unicode-safe skip-table */
 212                         int h, n, he, ne, hc, nc, i;
 213
 214                         if (haystack == null || needle == null)
 215                                 throw new ArgumentNullException ();
 216
 217                         /* if the search buffer is shorter than the pattern buffer, we can't match */
 218                         if (count < needle.length)
 219                                 return -1;
 220
 221                         /* return an instant match if the pattern is 0-length */
 222                         if (needle.length == 0)
 223                                 return startIndex;
 224
 225                         /* set a pointer at the end of each string */
 226                         ne = needle.length - 1;      /* position of char before '\0' */
 227                         he = startIndex + count;     /* position of last valid char */
 228
 229                         /* init the skip table with the pattern length */
 230                         nc = needle.length;
 231                         for (i = 0; i < 65536; i++)
 232                                 skiptable[i] = nc;
 233
 234                         /* set the skip value for the chars that *do* appear in the
 235                          * pattern buffer (needle) to the distance from the index to
 236                          * the end of the pattern buffer. */
 237                         for (nc = 0; nc < ne; nc++)
 238                                 skiptable[(int) needle[nc]] = ne - nc;
 239
 240                         h = startIndex;
 241                         while (count >= needle.length) {
 242                                 hc = h + needle.length - 1;  /* set the haystack compare pointer */
 243                                 nc = ne;                     /* set the needle compare pointer */
 244
 245                                 /* work our way backwards until they don't match */
 246                                 for (i = 0; nc > 0; nc--, hc--, i++)
 247                                         if (needle[nc] != haystack[hc])
 248                                                 break;
 249
 250                                 if (needle[nc] != haystack[hc]) {
 251                                         n = skiptable[(int) haystack[hc]] - i;
 252                                         h += n;
 253                                         count -= n;
 254                                 } else
 255                                         return h;
 256                         }
 257
 258                         return -1;
 259                 }
 260
 261                 // Methods
 262                 [MonoTODO]
 263                 public object Clone ()
 264                 {
 265                         // FIXME: implement me
 266                         return null;
 267                 }
 268
 269                 public static int Compare (string strA, string strB)
 270                 {
 271                         int min, i;
 272
 273                         if (strA == null) {
 274                                 if (strB == null)
 275                                         return 0;
 276                                 else
 277                                         return -1;
 278                         } else if (strB == null)
 279                                 return 1;
 280
 281                         min = strA.length < strB.length ? strA.length : strB.length;
 282
 283                         for (i = 0; i < min; i++) {
 284                                 if (strA.c_str[i] != strB.c_str[i]) {
 285                                         return (int)strA.c_str[i] - (int)strB.c_str[i];
 286                                 }
 287                         }
 288                         if (strA.length == strB.length) {
 289                                 return 0;
 290                         }
 291                         if (strA.length > min) {
 292                                 return 1;
 293                         } else {
 294                                 return -1;
 295                         }
 296                 }
 297
 298                 public static int Compare (string strA, string strB, bool ignoreCase)
 299                 {
 300                         int min, i;
 301
 302                         if (!ignoreCase)
 303                                 return Compare (strA, strB);
 304
 305                         /*
 306                          * And here I thought Eazel developers were on crack...
 307                          * if a string is null it should pelt the programmer with
 308                          * ArgumentNullExceptions, damnit!
 309                          */
 310                         if (strA == null) {
 311                                 if (strB == null)
 312                                         return 0;
 313                                 else
 314                                         return -1;
 315                         } else if (strB == null)
 316                                 return 1;
 317
 318                         min = strA.length < strB.length ? strA.length : strB.length;
 319
 320                         for (i = 0; i < min; i++) {
 321                                 if (Char.ToLower (strA.c_str[i]) != Char.ToLower (strB.c_str[i])) {
 322                                         return (int)strA.c_str[i] - (int)strB.c_str[i];
 323                                 }
 324                         }
 325                         if (strA.length == strB.length) {
 326                                 return 0;
 327                         }
 328                         if (strA.length > min) {
 329                                 return 1;
 330                         } else {
 331                                 return -1;
 332                         }
 333                 }
 334
 335                 [MonoTODO]
 336                 public static int Compare (string strA, string strB, bool ignoreCase, CultureInfo culture)
 337                 {
 338                         // FIXME: implement me
 339                         return 0;
 340                 }
 341
 342                 public static int Compare (string strA, int indexA, string strB, int indexB, int length)
 343                 {
 344                         int i;
 345
 346                         if (length < 0 || indexA < 0 || indexB < 0)
 347                                 throw new ArgumentOutOfRangeException ();
 348
 349                         if (indexA > strA.Length || indexB > strB.Length)
 350                                 throw new ArgumentOutOfRangeException ();
 351
 352                         /* And again with the ("" > null) logic... lord have mercy! */
 353                         if (strA == null) {
 354                                 if (strB == null)
 355                                         return 0;
 356                                 else
 357                                         return -1;
 358                         } else if (strB == null)
 359                                 return 1;
 360
 361                         for (i = 0; i < length - 1; i++) {
 362                                 if (strA[indexA + i] != strB[indexB + i])
 363                                         break;
 364                         }
 365
 366                         return ((int) (strA[indexA + i] - strB[indexB + i]));
 367                 }
 368
 369                 public static int Compare (string strA, int indexA, string strB, int indexB,
 370                                            int length, bool ignoreCase)
 371                 {
 372                         int i;
 373
 374                         if (!ignoreCase)
 375                                 return Compare (strA, indexA, strB, indexB, length);
 376
 377                         if (length < 0 || indexA < 0 || indexB < 0)
 378                                 throw new ArgumentOutOfRangeException ();
 379
 380                         if (indexA > strA.Length || indexB > strB.Length)
 381                                 throw new ArgumentOutOfRangeException ();
 382
 383                         /* When will the hurting stop!?!? */
 384                         if (strA == null) {
 385                                 if (strB == null)
 386                                         return 0;
 387                                 else
 388                                         return -1;
 389                         } else if (strB == null)
 390                                 return 1;
 391
 392                         for (i = 0; i < length - 1; i++) {
 393                                 if (Char.ToLower (strA[indexA + i]) != Char.ToLower (strB[indexB + i]))
 394                                         break;
 395                         }
 396
 397                         return ((int) (strA[indexA + i] - strB[indexB + i]));
 398                 }
 399
 400                 [MonoTODO]
 401                 public static int Compare (string strA, int indexA, string strB, int indexB,
 402                                            int length, bool ignoreCase, CultureInfo culture)
 403                 {
 404                         if (culture == null)
 405                                 throw new ArgumentNullException ();
 406
 407                         if (length < 0 || indexA < 0 || indexB < 0)
 408                                 throw new ArgumentOutOfRangeException ();
 409
 410                         if (indexA > strA.Length || indexB > strB.Length)
 411                                 throw new ArgumentOutOfRangeException ();
 412
 413                         /* I can't take it anymore! */
 414                         if (strA == null) {
 415                                 if (strB == null)
 416                                         return 0;
 417                                 else
 418                                         return -1;
 419                         } else if (strB == null)
 420                                 return 1;
 421
 422                         // FIXME: implement me
 423                         return 0;
 424                 }
 425
 426                 public static int CompareOrdinal (string strA, string strB)
 427                 {
 428                         int i;
 429
 430                         /* Please God, make it stop! */
 431                         if (strA == null) {
 432                                 if (strB == null)
 433                                         return 0;
 434                                 else
 435                                         return -1;
 436                         } else if (strB == null)
 437                                 return 1;
 438
 439                         for (i = 0; i < strA.Length && i < strB.Length; i++) {
 440                                 char cA, cB;
 441
 442                                 cA = tolowerordinal (strA[i]);
 443                                 cB = tolowerordinal (strB[i]);
 444
 445                                 if (cA != cB)
 446                                         break;
 447                         }
 448
 449                         return ((int) (strA[i] - strB[i]));
 450                 }
 451
 452                 public static int CompareOrdinal (string strA, int indexA, string strB, int indexB,
 453                                                   int length)
 454                 {
 455                         int i;
 456
 457                         if (length < 0 || indexA < 0 || indexB < 0)
 458                                 throw new ArgumentOutOfRangeException ();
 459
 460                         if (strA == null) {
 461                                 if (strB == null)
 462                                         return 0;
 463                                 else
 464                                         return -1;
 465                         } else if (strB == null)
 466                                 return 1;
 467
 468                         for (i = 0; i < length; i++) {
 469                                 char cA, cB;
 470
 471                                 cA = tolowerordinal (strA[indexA + i]);
 472                                 cB = tolowerordinal (strB[indexB + i]);
 473
 474                                 if (cA != cB)
 475                                         break;
 476                         }
 477
 478                         return ((int) (strA[indexA + i] - strB[indexB + i]));
 479                 }
 480
 481                 public int CompareTo (object obj)
 482                 {
 483                         return Compare (this, obj == null ? null : obj.ToString ());
 484                 }
 485
 486                 public int CompareTo (string str)
 487                 {
 488                         return Compare (this, str);
 489                 }
 490
 491                 public static string Concat (object arg)
 492                 {
 493                         return arg != null ? arg.ToString () : String.Empty;
 494                 }
 495
 496                 public static string Concat (params object[] args)
 497                 {
 498                         string[] strings;
 499                         char[] str;
 500                         int len, i;
 501
 502                         if (args == null)
 503                                 throw new ArgumentNullException ();
 504
 505                         strings = new string [args.Length];
 506                         len = 0;
 507                         i = 0;
 508                         foreach (object arg in args) {
 509                                 /* use Empty for each null argument */
 510                                 if (arg == null)
 511                                         strings[i] = String.Empty;
 512                                 else
 513                                         strings[i] = arg.ToString ();
 514                                 len += strings[i].length;
 515                                 i++;
 516                         }
 517
 518                         if (len == 0)
 519                                 return String.Empty;
 520
 521                         String res = new String (len);
 522                         str = res.c_str;
 523                         i = 0;
 524                         for (int j = 0; j < strings.Length; j++)
 525                                 for (int k = 0; k < strings[j].length; k++)
 526                                         str[i++] = strings[j].c_str[k];
 527
 528                         return res;
 529                 }
 530
 531                 public static string Concat (params string[] values)
 532                 {
 533                         int len, i;
 534                         char[] str;
 535
 536                         if (values == null)
 537                                 throw new ArgumentNullException ();
 538
 539                         len = 0;
 540                         foreach (string value in values)
 541                                 len += value != null ? value.Length : 0;
 542
 543                         if (len == 0)
 544                                 return String.Empty;
 545
 546                         String res = new String (len);
 547                         str = res.c_str;
 548                         i = 0;
 549                         foreach (string value in values) {
 550                                 if (value == null)
 551                                         continue;
 552
 553                                 for (int j = 0; j < value.length; j++)
 554                                         str[i++] = value.c_str[j];
 555                         }
 556
 557                         return res;
 558                 }
 559
 560                 public static string Concat (object arg0, object arg1)
 561                 {
 562                         string str0 = arg0 != null ? arg0.ToString () : String.Empty;
 563                         string str1 = arg1 != null ? arg1.ToString () : String.Empty;
 564
 565                         return Concat (str0, str1);
 566                 }
 567
 568                 public static string Concat (string str0, string str1)
 569                 {
 570                         char[] concat;
 571                         int i, j, len;
 572
 573                         if (str0 == null)
 574                                 str0 = String.Empty;
 575                         if (str1 == null)
 576                                 str1 = String.Empty;
 577
 578                         len = str0.length + str1.length;
 579                         if (len == 0)
 580                                 return String.Empty;
 581
 582                         String res = new String (len);
 583
 584                         concat = res.c_str;
 585                         for (i = 0; i < str0.length; i++)
 586                                 concat[i] = str0.c_str[i];
 587                         for (j = 0 ; j < str1.length; j++)
 588                                 concat[i + j] = str1.c_str[j];
 589
 590                         return res;
 591                 }
 592
 593                 public static string Concat (object arg0, object arg1, object arg2)
 594                 {
 595                         string str0 = arg0 != null ? arg0.ToString () : String.Empty;
 596                         string str1 = arg1 != null ? arg1.ToString () : String.Empty;
 597                         string str2 = arg2 != null ? arg2.ToString () : String.Empty;
 598
 599                         return Concat (str0, str1, str2);
 600                 }
 601
 602                 public static string Concat (string str0, string str1, string str2)
 603                 {
 604                         char[] concat;
 605                         int i, j, k, len;
 606
 607                         if (str0 == null)
 608                                 str0 = String.Empty;
 609                         if (str1 == null)
 610                                 str1 = String.Empty;
 611                         if (str2 == null)
 612                                 str2 = String.Empty;
 613
 614                         len = str0.length + str1.length + str2.length;
 615                         if (len == 0)
 616                                 return String.Empty;
 617
 618                         String res = new String (len);
 619
 620                         concat = res.c_str;
 621                         for (i = 0; i < str0.length; i++)
 622                                 concat[i] = str0.c_str[i];
 623                         for (j = 0; j < str1.length; j++)
 624                                 concat[i + j] = str1.c_str[j];
 625                         for (k = 0; k < str2.length; k++)
 626                                 concat[i + j + k] = str2.c_str[k];
 627
 628                         return res;
 629                 }
 630
 631                 public static string Concat (string str0, string str1, string str2, string str3)
 632                 {
 633                         char[] concat;
 634                         int i, j, k, l, len;
 635
 636                         if (str0 == null)
 637                                 str0 = String.Empty;
 638                         if (str1 == null)
 639                                 str1 = String.Empty;
 640                         if (str2 == null)
 641                                 str2 = String.Empty;
 642                         if (str3 == null)
 643                                 str3 = String.Empty;
 644
 645                         len = str0.length + str1.length + str2.length + str3.length;
 646                         if (len == 0)
 647                                 return String.Empty;
 648                         String res = new String (len);
 649
 650                         concat = res.c_str;
 651                         for (i = 0; i < str0.length; i++)
 652                                 concat[i] = str0.c_str[i];
 653                         for (j = 0; j < str1.length; j++)
 654                                 concat[i + j] = str1.c_str[j];
 655                         for (k = 0; k < str2.length; k++)
 656                                 concat[i + j + k] = str2.c_str[k];
 657                         for (l = 0; l < str3.length; l++)
 658                                 concat[i + j + k + l] = str3.c_str[l];
 659
 660                         return res;
 661                 }
 662
 663                 public static string Copy (string str)
 664                 {
 665                         // FIXME: how do I *copy* a string if I can only have 1 of each?
 666                         if (str == null)
 667                                 throw new ArgumentNullException ();
 668
 669                         return str;
 670                 }
 671
 672                 public void CopyTo (int sourceIndex, char[] destination, int destinationIndex, int count)
 673                 {
 674                         // LAMESPEC: should I null-terminate?
 675                         int i;
 676
 677                         if (destination == null)
 678                                 throw new ArgumentNullException ();
 679
 680                         if (sourceIndex < 0 || destinationIndex < 0 || count < 0)
 681                                 throw new ArgumentOutOfRangeException ();
 682
 683                         if (sourceIndex + count > this.length)
 684                                 throw new ArgumentOutOfRangeException ();
 685
 686                         if (destinationIndex + count > destination.Length)
 687                                 throw new ArgumentOutOfRangeException ();
 688
 689                         for (i = 0; i < count; i++)
 690                                 destination[destinationIndex + i] = this.c_str[sourceIndex + i];
 691                 }
 692
 693                 public bool EndsWith (string value)
 694                 {
 695                         bool endswith = true;
 696                         int start, i;
 697
 698                         if (value == null)
 699                                 throw new ArgumentNullException ();
 700
 701                         start = this.length - value.length;
 702                         if (start < 0)
 703                                 return false;
 704
 705                         for (i = start; i < this.length && endswith; i++)
 706                                 endswith = this.c_str[i] == value.c_str[i - start];
 707
 708                         return endswith;
 709                 }
 710
 711                 public override bool Equals (object obj)
 712                 {
 713                         if (!(obj is String))
 714                                 return false;
 715
 716                         return this == (String) obj;
 717                 }
 718
 719                 public bool Equals (string value)
 720                 {
 721                         return this == value;
 722                 }
 723
 724                 public static bool Equals (string a, string b)
 725                 {
 726                         return a == b;
 727                 }
 728
 729                 [MonoTODO]
 730                 public static string Format (string format, object arg0)
 731                 {
 732                         // FIXME: implement me
 733                         return format+arg0.ToString();
 734                 }
 735
 736                 [MonoTODO]
 737                 public static string Format (string format, params object[] args)
 738                 {
 739                         // FIXME: implement me
 740                         Console.WriteLine (args[0].ToString());
 741                         if (args.Length == 1)
 742                                 return format+args[0].ToString();
 743                         if (args.Length == 2)
 744                                 return format+args[0].ToString()+args[1].ToString();
 745                         if (args.Length == 3)
 746                                 return format+args[0].ToString()+args[1].ToString()+args[2].ToString();
 747                         if (args.Length == 4)
 748                                 return format+args[0].ToString()+args[1].ToString()+args[2].ToString()+args[3].ToString();
 749                         Console.WriteLine ("String.Format with args: "+args.Length.ToString());
 750                         return format;
 751                 }
 752
 753                 [MonoTODO]
 754                 public static string Format (IFormatProvider provider, string format, params object[] args)
 755                 {
 756                         // FIXME: implement me
 757                         return null;
 758                 }
 759
 760                 [MonoTODO]
 761                 public static string Format (string format, object arg0, object arg1)
 762                 {
 763                         // FIXME: implement me
 764                         return format+arg0.ToString()+arg1.ToString();
 765                 }
 766
 767                 [MonoTODO]
 768                 public static string Format (string format, object arg0, object arg1, object arg2)
 769                 {
 770                         // FIXME: implement me
 771                         return format+arg0.ToString()+arg1.ToString()+arg2.ToString();
 772                 }
 773
 774                 public CharEnumerator GetEnumerator ()
 775                 {
 776                         return new CharEnumerator (this);
 777                 }
 778
 779                 IEnumerator IEnumerable.GetEnumerator ()
 780                 {
 781                         return new CharEnumerator (this);
 782                 }
 783
 784                 public override int GetHashCode ()
 785                 {
 786                         int h = 0;
 787                         int i;
 788                         for (i = 0; i < length; ++i)
 789                                 h = (h << 5) - h + c_str [i];
 790                         return h;
 791                 }
 792
 793                 public TypeCode GetTypeCode ()
 794                 {
 795                         return TypeCode.String;
 796                 }
 797
 798                 public int IndexOf (char value)
 799                 {
 800                         return IndexOf (value, 0, this.length);
 801                 }
 802
 803                 public int IndexOf (string value)
 804                 {
 805                         return IndexOf (value, 0, this.length);
 806                 }
 807
 808                 public int IndexOf (char value, int startIndex)
 809                 {
 810                         return IndexOf (value, startIndex, this.length - startIndex);
 811                 }
 812
 813                 public int IndexOf (string value, int startIndex)
 814                 {
 815                         return IndexOf (value, startIndex, this.length - startIndex);
 816                 }
 817
 818                 public int IndexOf (char value, int startIndex, int count)
 819                 {
 820                         int i;
 821
 822                         if (startIndex < 0 || count < 0 || startIndex + count > this.length)
 823                                 throw new ArgumentOutOfRangeException ();
 824
 825                         for (i = startIndex; i - startIndex < count; i++)
 826                                 if (this.c_str[i] == value)
 827                                         return i;
 828
 829                         return -1;
 830                 }
 831
 832                 public int IndexOf (string value, int startIndex, int count)
 833                 {
 834                         if (value == null)
 835                                 throw new ArgumentNullException ();
 836
 837                         if (startIndex < 0 || count < 0 || startIndex + count > this.length)
 838                                 throw new ArgumentOutOfRangeException ();
 839
 840                         return BoyerMoore (this.c_str, value, startIndex, count);
 841 #if XXX
 842                         int i;
 843                         for (i = startIndex; i - startIndex + value.Length <= count; ) {
 844                                 if (this.c_str[i] == value[0]) {
 845                                         bool equal = true;
 846                                         int j, nexti = 0;
 847
 848                                         for (j = 1; equal && j < value.Length; j++) {
 849                                                 equal = this.c_str[i + j] == value[j];
 850                                                 if (this.c_str[i + j] == value[0] && nexti == 0)
 851                                                         nexti = i + j;
 852                                         }
 853
 854                                         if (equal)
 855                                                 return i;
 856
 857                                         if (nexti != 0)
 858                                                 i = nexti;
 859                                         else
 860                                                 i += j;
 861                                 } else
 862                                         i++;
 863                         }
 864
 865                         return -1;
 866 #endif
 867                 }
 868
 869                 public int IndexOfAny (char[] values)
 870                 {
 871                         return IndexOfAny (values, 0, this.length);
 872                 }
 873
 874                 public int IndexOfAny (char[] values, int startIndex)
 875                 {
 876                         return IndexOfAny (values, startIndex, this.length - startIndex);
 877                 }
 878
 879                 public int IndexOfAny (char[] values, int startIndex, int count)
 880                 {
 881                         if (values == null)
 882                                 throw new ArgumentNullException ();
 883
 884                         if (startIndex < 0 || count < 0 || startIndex + count > this.length)
 885                                 throw new ArgumentOutOfRangeException ();
 886
 887                         for (int i = startIndex; i < startIndex + count; i++) {
 888                                 for (int j = 0; j < strlen (values); j++) {
 889                                         if (this.c_str[i] == values[j])
 890                                                 return i;
 891                                 }
 892                         }
 893
 894                         return -1;
 895                 }
 896
 897                 public string Insert (int startIndex, string value)
 898                 {
 899                         char[] str;
 900                         int i, j;
 901
 902                         if (value == null)
 903                                 throw new ArgumentNullException ();
 904
 905                         if (startIndex < 0 || startIndex > this.length)
 906                                 throw new ArgumentOutOfRangeException ();
 907
 908                         String res = new String (value.length + this.length);
 909
 910                         str = res.c_str;
 911                         for (i = 0; i < startIndex; i++)
 912                                 str[i] = this.c_str[i];
 913                         for (j = 0; j < value.length; j++)
 914                                 str[i + j] = value.c_str[j];
 915                         for ( ; i < this.length; i++)
 916                                 str[i + j] = this.c_str[i];
 917
 918                         return res;
 919                 }
 920
 921                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
 922                 public extern static string Intern (string str);
 923
 924                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
 925                 public extern static string IsInterned (string str);
 926
 927                 public static string Join (string separator, string[] value)
 928                 {
 929                         return Join (separator, value, 0, value.Length);
 930                 }
 931
 932                 public static string Join (string separator, string[] value, int startIndex, int count)
 933                 {
 934                         // LAMESPEC: msdn doesn't specify what happens when separator is null
 935                         int len, i, j, used;
 936                         char[] str;
 937
 938                         if (separator == null || value == null)
 939                                 throw new ArgumentNullException ();
 940
 941                         if (startIndex + count > value.Length)
 942                                 throw new ArgumentOutOfRangeException ();
 943
 944                         len = 0;
 945                         for (i = startIndex, used = 0; used < count; i++, used++) {
 946                                 if (i != startIndex)
 947                                         len += separator.length;
 948
 949                                 len += value[i].length;
 950                         }
 951
 952                         // We have no elements to join?
 953                         if (i == startIndex)
 954                                 return String.Empty;
 955
 956                         String res = new String (len);
 957
 958                         str = res.c_str;
 959                         for (i = 0; i < value[startIndex].length; i++)
 960                                 str[i] = value[startIndex][i];
 961
 962                         used = 1;
 963                         for (j = startIndex + 1; used < count; j++, used++) {
 964                                 int k;
 965
 966                                 for (k = 0; k < separator.length; k++)
 967                                         str[i++] = separator.c_str[k];
 968                                 for (k = 0; k < value[j].length; k++)
 969                                         str[i++] = value[j].c_str[k];
 970                         }
 971
 972                         return res;
 973                 }
 974
 975                 public int LastIndexOf (char value)
 976                 {
 977                         int i = this.length;
 978                         if (i == 0)
 979                                 return -1;
 980                         --i;
 981                         for (; i >= 0; i--) {
 982                                 if (this.c_str[i] == value)
 983                                         return i;
 984                         }
 985
 986                         return -1;
 987                 }
 988
 989                 public int LastIndexOf (string value)
 990                 {
 991                         return LastIndexOf (value, this.length - 1, this.length);
 992                 }
 993
 994                 public int LastIndexOf (char value, int startIndex)
 995                 {
 996                         if (startIndex < 0 || startIndex >= this.length)
 997                                 throw new ArgumentOutOfRangeException ();
 998
 999                         for (int i = startIndex; i >= 0; i--) {
1000                                 if (this.c_str[i] == value)
1001                                         return i;
1002                         }
1003
1004                         return -1;
1005                 }
1006
1007                 public int LastIndexOf (string value, int startIndex)
1008                 {
1009                         return LastIndexOf (value, startIndex, startIndex + 1);
1010                 }
1011
1012                 public int LastIndexOf (char value, int startIndex, int count)
1013                 {
1014                         if (startIndex < 0 || count < 0)
1015                                 throw new ArgumentOutOfRangeException ();
1016
1017                         if (startIndex >= this.length || startIndex - count + 1 < 0)
1018                                 throw new ArgumentOutOfRangeException ();
1019
1020                         for (int i = startIndex; i > startIndex - count; i--) {
1021                                 if (this.c_str[i] == value)
1022                                         return i;
1023                         }
1024
1025                         return -1;
1026                 }
1027
1028                 public int LastIndexOf (string value, int startIndex, int count)
1029                 {
1030                         // LAMESPEC: currently I'm using startIndex as the 0-position in the comparison,
1031                         //           but maybe it's the end-position in MS's implementation?
1032                         //           msdn is unclear on this point. I think this is correct though.
1033                         int i, len;
1034
1035                         if (value == null)
1036                                 throw new ArgumentNullException ();
1037
1038                         if (startIndex < 0 || startIndex >= this.length)
1039                                 throw new ArgumentOutOfRangeException ();
1040
1041                         if (count < 0 || startIndex - count + 1 < 0)
1042                                 throw new ArgumentOutOfRangeException ();
1043
1044                         if (value == String.Empty)
1045                                 return startIndex;
1046
1047                         if (startIndex + value.length > this.length) {
1048                                 /* just a little optimization */
1049                                 int start;
1050
1051                                 start = this.length - value.length;
1052                                 count -= startIndex - start;
1053                                 startIndex = start;
1054                         }
1055
1056                         // FIXME: use a reversed-unicode-safe-Boyer-Moore?
1057                         len = value.length - 1;
1058                         for (i = startIndex; i > startIndex - count; i--) {
1059                                 if (this.c_str[i + len] == value.c_str[len]) {
1060                                         bool equal = true;
1061                                         int j;
1062
1063                                         for (j = len - 1; equal && j >= 0; j--)
1064                                                 equal = this.c_str[i + j] == value.c_str[j];
1065
1066                                         if (equal)
1067                                                 return i;
1068                                 }
1069                         }
1070
1071                         return -1;
1072                 }
1073
1074                 public int LastIndexOfAny (char[] values)
1075                 {
1076                         return LastIndexOfAny (values, this.length - 1, this.length);
1077                 }
1078
1079                 public int LastIndexOfAny (char[] values, int startIndex)
1080                 {
1081                         return LastIndexOfAny (values, startIndex, startIndex + 1);
1082                 }
1083
1084                 public int LastIndexOfAny (char[] values, int startIndex, int count)
1085                 {
1086                         int i;
1087
1088                         if (values == null)
1089                                 throw new ArgumentNullException ();
1090
1091                         if (startIndex < 0 || count < 0 || startIndex - count + 1 < 0)
1092                                 throw new ArgumentOutOfRangeException ();
1093
1094                         for (i = startIndex; i > startIndex - count; i--) {
1095                                 for (int j = 0; j < strlen (values); j++) {
1096                                         if (this.c_str[i] == values[j])
1097                                                 return i;
1098                                 }
1099                         }
1100
1101                         return -1;
1102                 }
1103
1104                 public string PadLeft (int totalWidth)
1105                 {
1106                         return PadLeft (totalWidth, ' ');
1107                 }
1108
1109                 public string PadLeft (int totalWidth, char padChar)
1110                 {
1111                         char[] str;
1112                         int i, j;
1113
1114                         if (totalWidth < 0)
1115                                 throw new ArgumentException ();
1116
1117                         str = new char [totalWidth > this.length ? totalWidth : this.length];
1118                         for (i = 0; i < totalWidth - this.length; i++)
1119                                 str[i] = padChar;
1120
1121                         for (j = 0; j < this.length; i++, j++)
1122                                 str[i] = this.c_str[j];
1123
1124                         return new String (str);
1125                 }
1126
1127                 public string PadRight (int totalWidth)
1128                 {
1129                         return PadRight (totalWidth, ' ');
1130                 }
1131
1132                 public string PadRight (int totalWidth, char padChar)
1133                 {
1134                         char[] str;
1135                         int i;
1136
1137                         if (totalWidth < 0)
1138                                 throw new ArgumentException ();
1139
1140                         str = new char [totalWidth > this.length ? totalWidth : this.length];
1141                         for (i = 0; i < this.length; i++)
1142                                 str[i] = this.c_str[i];
1143
1144                         for ( ; i < str.Length; i++)
1145                                 str[i] = padChar;
1146
1147                         return new String (str);
1148                 }
1149
1150                 public string Remove (int startIndex, int count)
1151                 {
1152                         char[] str;
1153                         int i, j, len;
1154
1155                         if (startIndex < 0 || count < 0 || startIndex + count > this.length)
1156                                 throw new ArgumentOutOfRangeException ();
1157
1158                         len = this.length - count;
1159                         if (len == 0)
1160                                 return String.Empty;
1161
1162                         String res = new String (len);
1163                         str = res.c_str;
1164                         for (i = 0; i < startIndex; i++)
1165                                 str[i] = this.c_str[i];
1166                         for (j = i + count; j < this.length; j++)
1167                                 str[i++] = this.c_str[j];
1168
1169                         return res;
1170                 }
1171
1172                 public string Replace (char oldChar, char newChar)
1173                 {
1174                         char[] str;
1175                         int i;
1176
1177                         String res = new String (length);
1178                         str = res.c_str;
1179                         for (i = 0; i < this.length; i++) {
1180                                 if (this.c_str[i] == oldChar)
1181                                         str[i] = newChar;
1182                                 else
1183                                         str[i] = this.c_str[i];
1184                         }
1185
1186                         return res;
1187                 }
1188
1189                 public string Replace (string oldValue, string newValue)
1190                 {
1191                         // LAMESPEC: msdn doesn't specify what to do if either args is null
1192                         int index, len, i, j;
1193                         char[] str;
1194
1195                         if (oldValue == null || newValue == null)
1196                                 throw new ArgumentNullException ();
1197
1198                         // Use IndexOf in case I later rewrite it to use Boyer-Moore
1199                         index = IndexOf (oldValue, 0);
1200                         if (index == -1) {
1201                                 // This is the easy one ;-)
1202                                 return Substring (0, this.length);
1203                         }
1204
1205                         len = this.length - oldValue.length + newValue.length;
1206                         if (len == 0)
1207                                 return String.Empty;
1208
1209                         String res = new String (len);
1210                         str = res.c_str;
1211                         for (i = 0; i < index; i++)
1212                                 str[i] = this.c_str[i];
1213                         for (j = 0; j < newValue.length; j++)
1214                                 str[i++] = newValue[j];
1215                         for (j = index + oldValue.length; j < this.length; j++)
1216                                 str[i++] = this.c_str[j];
1217
1218                         return res;
1219                 }
1220
1221                 private int splitme (char[] separators, int startIndex)
1222                 {
1223                         /* this is basically a customized IndexOfAny() for the Split() methods */
1224                         for (int i = startIndex; i < this.length; i++) {
1225                                 if (separators != null) {
1226                                         foreach (char sep in separators) {
1227                                                 if (this.c_str[i] == sep)
1228                                                         return i - startIndex;
1229                                         }
1230                                 } else if (is_lwsp (this.c_str[i])) {
1231                                         return i - startIndex;
1232                                 }
1233                         }
1234
1235                         return -1;
1236                 }
1237
1238                 public string[] Split (params char[] separator)
1239                 {
1240                         /**
1241                          * split:
1242                          * @separator: delimiting chars or null to split on whtspc
1243                          *
1244                          * Returns: 1. An array consisting of a single
1245                          * element (@this) if none of the delimiting
1246                          * chars appear in @this. 2. An array of
1247                          * substrings which are delimited by one of
1248                          * the separator chars. 3. An array of
1249                          * substrings separated by whitespace if
1250                          * @separator is null. The Empty string should
1251                          * be returned wherever 2 delimiting chars are
1252                          * adjacent.
1253                          **/
1254                         // FIXME: would using a Queue be better?
1255                         string[] strings;
1256                         ArrayList list;
1257                         int index, len;
1258
1259                         list = new ArrayList ();
1260                         for (index = 0, len = 0; index < this.length; index += len + 1) {
1261                                 len = splitme (separator, index);
1262                                 len = len > -1 ? len : this.length - index;
1263                                 if (len == 0) {
1264                                         list.Add (String.Empty);
1265                                 } else {
1266                                         char[] str;
1267                                         int i;
1268
1269                                         str = new char [len];
1270                                         for (i = 0; i < len; i++)
1271                                                 str[i] = this.c_str[index + i];
1272
1273                                         list.Add (new String (str));
1274                                 }
1275                         }
1276
1277                         strings = new string [list.Count];
1278                         if (list.Count == 1) {
1279                                 /* special case for an array holding @this */
1280                                 strings[0] = this;
1281                         } else {
1282                                 for (index = 0; index < list.Count; index++)
1283                                         strings[index] = (string) list[index];
1284                         }
1285
1286                         return strings;
1287                 }
1288
1289                 public string[] Split (char[] separator, int maxCount)
1290                 {
1291                         // FIXME: what to do if maxCount <= 0?
1292                         // FIXME: would using Queue be better than ArrayList?
1293                         string[] strings;
1294                         ArrayList list;
1295                         int index, len, used;
1296
1297                         used = 0;
1298                         list = new ArrayList ();
1299                         for (index = 0, len = 0; index < this.length && used < maxCount; index += len + 1) {
1300                                 len = splitme (separator, index);
1301                                 len = len > -1 ? len : this.length - index;
1302                                 if (len == 0) {
1303                                         list.Add (String.Empty);
1304                                 } else {
1305                                         char[] str;
1306                                         int i;
1307
1308                                         str = new char [len];
1309                                         for (i = 0; i < len; i++)
1310                                                 str[i] = this.c_str[index + i];
1311
1312                                         list.Add (new String (str));
1313                                 }
1314                                 used++;
1315                         }
1316
1317                         /* fit the remaining chunk of the @this into it's own element */
1318                         if (index != this.length) {
1319                                 char[] str;
1320                                 int i;
1321
1322                                 str = new char [this.length - index];
1323                                 for (i = index; i < this.length; i++)
1324                                         str[i - index] = this.c_str[i];
1325
1326                                 list.Add (new String (str));
1327                         }
1328
1329                         strings = new string [list.Count];
1330                         if (list.Count == 1) {
1331                                 /* special case for an array holding @this */
1332                                 strings[0] = this;
1333                         } else {
1334                                 for (index = 0; index < list.Count; index++)
1335                                         strings[index] = (string) list[index];
1336                         }
1337
1338                         return strings;
1339                 }
1340
1341                 public bool StartsWith (string value)
1342                 {
1343                         bool startswith = true;
1344                         int i;
1345
1346                         if (value == null)
1347                                 throw new ArgumentNullException ();
1348
1349                         if (value.length > this.length)
1350                                 return false;
1351
1352                         for (i = 0; i < value.length && startswith; i++)
1353                                 startswith = startswith && value.c_str[i] == this.c_str[i];
1354
1355                         return startswith;
1356                 }
1357
1358                 public string Substring (int startIndex)
1359                 {
1360                         char[] str;
1361                         int i, len;
1362
1363                         if (startIndex < 0 || startIndex > this.length)
1364                                 throw new ArgumentOutOfRangeException ();
1365
1366                         len = this.length - startIndex;
1367                         if (len == 0)
1368                                 return String.Empty;
1369                         String res = new String (len);
1370                         str = res.c_str;
1371                         for (i = startIndex; i < this.length; i++)
1372                                 str[i - startIndex] = this.c_str[i];
1373
1374                         return res;
1375                 }
1376
1377                 public string Substring (int startIndex, int length)
1378                 {
1379                         char[] str;
1380                         int i;
1381
1382                         if (startIndex < 0 || length < 0 || startIndex + length > this.length)
1383                                 throw new ArgumentOutOfRangeException ();
1384
1385                         if (length == 0)
1386                                 return String.Empty;
1387
1388                         String res = new String (length);
1389                         str = res.c_str;
1390                         for (i = startIndex; i < startIndex + length; i++)
1391                                 str[i - startIndex] = this.c_str[i];
1392
1393                         return res;
1394                 }
1395
1396                 [MonoTODO]
1397                 public bool ToBoolean (IFormatProvider provider)
1398                 {
1399                         // FIXME: implement me
1400                         throw new NotImplementedException ();
1401                 }
1402
1403                 [MonoTODO]
1404                 public byte ToByte (IFormatProvider provider)
1405                 {
1406                         // FIXME: implement me
1407                         throw new NotImplementedException ();
1408                 }
1409
1410                 [MonoTODO]
1411                 public char ToChar (IFormatProvider provider)
1412                 {
1413                         // FIXME: implement me
1414                         throw new NotImplementedException ();
1415                 }
1416
1417                 public char[] ToCharArray ()
1418                 {
1419                         return ToCharArray (0, this.length);
1420                 }
1421
1422                 public char[] ToCharArray (int startIndex, int length)
1423                 {
1424                         char[] chars;
1425                         int i;
1426
1427                         if (startIndex < 0 || length < 0 || startIndex + length > this.length)
1428                                 throw new ArgumentOutOfRangeException ();
1429
1430                         chars = new char [length];
1431                         for (i = startIndex; i < length; i++)
1432                                 chars[i - startIndex] = this.c_str[i];
1433
1434                         return chars;
1435                 }
1436
1437                 [MonoTODO]
1438                 public DateTime ToDateTime (IFormatProvider provider)
1439                 {
1440                         // FIXME: implement me
1441                         // return new DateTime (0);
1442                         throw new NotImplementedException ();
1443                 }
1444
1445                 [MonoTODO]
1446                 public decimal ToDecimal (IFormatProvider provider)
1447                 {
1448                         // FIXME: implement me
1449                         throw new NotImplementedException ();
1450                 }
1451
1452                 [MonoTODO]
1453                 public double ToDouble (IFormatProvider provider)
1454                 {
1455                         // FIXME: implement me
1456                         throw new NotImplementedException ();
1457                 }
1458
1459                 [MonoTODO]
1460                 public short ToInt16 (IFormatProvider provider)
1461                 {
1462                         // FIXME: implement me
1463                         throw new NotImplementedException ();
1464                 }
1465
1466                 [MonoTODO]
1467                 public int ToInt32 (IFormatProvider provider)
1468                 {
1469                         // FIXME: implement me
1470                         throw new NotImplementedException ();
1471                 }
1472
1473                 [MonoTODO]
1474                 public long ToInt64 (IFormatProvider provider)
1475                 {
1476                         // FIXME: implement me
1477                         throw new NotImplementedException ();
1478                 }
1479
1480                 public string ToLower ()
1481                 {
1482                         char[] str;
1483                         int i;
1484
1485                         String res = new String (length);
1486                         str = res.c_str;
1487                         for (i = 0; i < this.length; i++)
1488                                 str[i] = Char.ToLower (this.c_str[i]);
1489
1490                         return res;
1491                 }
1492
1493                 [MonoTODO]
1494                 public string ToLower (CultureInfo culture)
1495                 {
1496                         // FIXME: implement me
1497                         throw new NotImplementedException ();
1498
1499                 }
1500
1501                 [CLSCompliant(false)][MonoTODO]
1502                 public sbyte ToSByte (IFormatProvider provider)
1503                 {
1504                         // FIXME: implement me
1505                         throw new NotImplementedException ();
1506                 }
1507
1508                 [MonoTODO]
1509                 public float ToSingle (IFormatProvider provider)
1510                 {
1511                         // FIXME: implement me
1512                         throw new NotImplementedException ();
1513                 }
1514
1515                 public override string ToString ()
1516                 {
1517                         return this;
1518                 }
1519
1520                 [MonoTODO]
1521                 public string ToString (IFormatProvider format)
1522                 {
1523                         // FIXME: implement me
1524                         throw new NotImplementedException ();
1525                 }
1526
1527                 [MonoTODO]
1528                 public object ToType (Type conversionType, IFormatProvider provider)
1529                 {
1530                         // FIXME: implement me
1531                         throw new NotImplementedException ();
1532                 }
1533
1534                 [CLSCompliant(false)][MonoTODO]
1535                 public ushort ToUInt16 (IFormatProvider provider)
1536                 {
1537                         // FIXME: implement me
1538                         throw new NotImplementedException ();
1539                 }
1540
1541                 [CLSCompliant(false)][MonoTODO]
1542                 public uint ToUInt32 (IFormatProvider provider)
1543                 {
1544                         // FIXME: implement me
1545                         throw new NotImplementedException ();
1546                 }
1547
1548                 [CLSCompliant(false)][MonoTODO]
1549                 public ulong ToUInt64 (IFormatProvider provider)
1550                 {
1551                         // FIXME: implement me
1552                         throw new NotImplementedException ();
1553                 }
1554
1555                 public string ToUpper ()
1556                 {
1557                         char[] str;
1558                         int i;
1559
1560                         String res = new String (length);
1561                         str = res.c_str;
1562                         for (i = 0; i < this.length; i++)
1563                                 str[i] = Char.ToUpper (this.c_str[i]);
1564
1565                         return res;
1566                 }
1567
1568                 [MonoTODO]
1569                 public string ToUpper (CultureInfo culture)
1570                 {
1571                         // FIXME: implement me
1572                         throw new NotImplementedException ();
1573                 }
1574
1575                 public string Trim ()
1576                 {
1577                         return Trim (null);
1578                 }
1579
1580                 public string Trim (params char[] trimChars)
1581                 {
1582                         int begin, end;
1583                         bool matches;
1584
1585                         matches = true;
1586                         for (begin = 0; matches && begin < this.length; begin++) {
1587                                 if (trimChars != null) {
1588                                         matches = false;
1589                                         foreach (char c in trimChars) {
1590                                                 matches = this.c_str[begin] == c;
1591                                                 if (matches)
1592                                                         break;
1593                                         }
1594                                 } else {
1595                                         matches = is_lwsp (this.c_str[begin]);
1596                                 }
1597                         }
1598
1599                         matches = true;
1600                         for (end = this.length - 1; matches && end > begin; end--) {
1601                                 if (trimChars != null) {
1602                                         matches = false;
1603                                         foreach (char c in trimChars) {
1604                                                 matches = this.c_str[end] == c;
1605                                                 if (matches)
1606                                                         break;
1607                                         }
1608                                 } else {
1609                                         matches = is_lwsp (this.c_str[end]);
1610                                 }
1611                         }
1612
1613                         if (begin >= end)
1614                                 return String.Empty;
1615
1616                         return Substring (begin, end - begin);
1617                 }
1618
1619                 public string TrimEnd (params char[] trimChars)
1620                 {
1621                         bool matches = true;
1622                         int end;
1623
1624                         for (end = this.length; end > 0; end--) {
1625                                 if (trimChars != null) {
1626                                         matches = false;
1627                                         foreach (char c in trimChars) {
1628                                                 matches = this.c_str[end] == c;
1629                                                 if (matches)
1630                                                         break;
1631                                         }
1632                                 } else {
1633                                         matches = is_lwsp (this.c_str[end]);
1634                                 }
1635                         }
1636
1637                         if (end == 0)
1638                                 return String.Empty;
1639
1640                         return Substring (0, end);
1641                 }
1642
1643                 public string TrimStart (params char[] trimChars)
1644                 {
1645                         bool matches = true;
1646                         int begin;
1647
1648                         for (begin = 0; matches && begin < this.length; begin++) {
1649                                 if (trimChars != null) {
1650                                         matches = false;
1651                                         foreach (char c in trimChars) {
1652                                                 matches = this.c_str[begin] == c;
1653                                                 if (matches)
1654                                                         break;
1655                                         }
1656                                 } else {
1657                                         matches = is_lwsp (this.c_str[begin]);
1658                                 }
1659                         }
1660
1661                         if (begin == this.length)
1662                                 return String.Empty;
1663
1664                         return Substring (begin, this.length - begin);
1665                 }
1666
1667                 // Operators
1668                 public static bool operator ==(string a, string b)
1669                 {
1670                         if ((object)a == null) {
1671                                 if ((object)b == null)
1672                                         return true;
1673                                 return false;
1674                         }
1675                         if ((object)b == null)
1676                                 return false;
1677
1678                         if (a.length != b.length)
1679                                 return false;
1680
1681                         int l = a.length;
1682                         for (int i = 0; i < l; i++)
1683                                 if (a.c_str[i] != b.c_str[i])
1684                                         return false;
1685
1686                         return true;
1687                 }
1688
1689                 public static bool operator !=(string a, string b)
1690                 {
1691                         return !(a == b);
1692                 }
1693         }
1694 }