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 // Authors:
   6 //   Jeffrey Stedfast (fejj@ximian.com)
   7 //   Dan Lewis (dihlewis@yahoo.co.uk)
   8 //
   9 // (C) 2001 Ximian, Inc.  http://www.ximian.com
  10 //
  11
  12 // FIXME: from what I gather from msdn, when a function is to return an empty string
  13 //        we should be returning this.Empty - some methods do this and others don't.
  14
  15 // FIXME: I didn't realise until later that `string' has a .Length method and so
  16 //        I am missing some proper bounds-checking in some methods. Find these
  17 //        instances and throw the ArgumentOutOfBoundsException at the programmer.
  18 //        I like pelting programmers with ArgumentOutOfBoundsException's :-)
  19
  20 // FIXME: The ToLower(), ToUpper(), and Compare(..., bool ignoreCase) methods
  21 //        need to be made unicode aware.
  22
  23 // FIXME: when you have a char carr[], does carr.Length include the terminating null char?
  24
  25 using System;
  26 using System.Text;
  27 using System.Collections;
  28 using System.Globalization;
  29 using System.Runtime.CompilerServices;
  30
  31 namespace System {
  32
  33         //[DefaultMemberName("Chars")]
  34         public sealed class String : IComparable, ICloneable, IConvertible, IEnumerable {
  35                 public static readonly string Empty = "";
  36                 private char[] c_str;
  37                 private int length;
  38
  39                 // Constructors
  40
  41                 internal String (int storage)
  42                 {
  43                         if (storage < 0)
  44                                 throw new ArgumentOutOfRangeException ();
  45                         length = storage;
  46                         c_str = new char [storage];
  47                 }
  48
  49                 [CLSCompliant(false)]
  50                 unsafe public String (char *value)
  51                 {
  52                         int i;
  53
  54                         // FIXME: can I do value.Length here?
  55                         if (value == null) {
  56                                 this.length = 0;
  57                         } else {
  58                                 for (i = 0; *(value + i) != '\0'; i++);
  59                                 this.length = i;
  60                         }
  61
  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                 }
  66
  67                 public String (char[] value)
  68                 {
  69                         int i;
  70
  71                         // FIXME: value.Length includes the terminating null char?
  72                         this.length = value != null ? strlen (value): 0;
  73                         this.c_str = new char [this.length + 1];
  74                         for (i = 0; i < this.length; i++)
  75                                 this.c_str[i] = value[i];
  76                 }
  77
  78                 [CLSCompliant(false)]
  79                 unsafe public String (sbyte *value)
  80                 {
  81                         // FIXME: consider unicode?
  82                         int i;
  83
  84                         // FIXME: can I do value.Length here? */
  85                         if (value == null) {
  86                                 this.length = 0;
  87                         } else {
  88                                 for (i = 0; *(value + i) != '\0'; i++);
  89                                 this.length = i;
  90                         }
  91
  92                         this.c_str = new char [this.length + 1];
  93                         for (i = 0; i < this.length; i++)
  94                                 this.c_str[i] = (char) *(value + i);
  95                 }
  96
  97                 public String (char c, int count)
  98                 {
  99                         int i;
 100
 101                         this.length = count;
 102                         this.c_str = new char [count + 1];
 103                         for (i = 0; i < count; i++)
 104                                 this.c_str[i] = c;
 105                 }
 106
 107                 [CLSCompliant(false)]
 108                 unsafe public String (char *value, int startIndex, int length)
 109                 {
 110                         int i;
 111
 112                         if (value == null && startIndex != 0 && length != 0)
 113                                 throw new ArgumentNullException ();
 114
 115                         if (startIndex < 0 || length < 0)
 116                                 throw new ArgumentOutOfRangeException ();
 117
 118                         this.length = length;
 119                         this.c_str = new char [length + 1];
 120                         for (i = 0; i < length; i++)
 121                                 this.c_str[i] = *(value + startIndex + i);
 122                 }
 123
 124                 public String (char[] value, int startIndex, int length)
 125                 {
 126                         int i;
 127
 128                         if (value == null && startIndex != 0 && length != 0)
 129                                 throw new ArgumentNullException ();
 130
 131                         if (startIndex < 0 || length < 0)
 132                                 throw new ArgumentOutOfRangeException ();
 133
 134                         this.length = length;
 135                         this.c_str = new char [length + 1];
 136                         for (i = 0; i < length; i++)
 137                                 this.c_str[i] = value[startIndex + i];
 138                 }
 139
 140                 [CLSCompliant(false)]
 141                 unsafe public String (sbyte *value, int startIndex, int length)
 142                 {
 143                         // FIXME: consider unicode?
 144                         int i;
 145
 146                         if (value == null && startIndex != 0 && length != 0)
 147                                 throw new ArgumentNullException ();
 148
 149                         if (startIndex < 0 || length < 0)
 150                                 throw new ArgumentOutOfRangeException ();
 151
 152                         this.length = length;
 153                         this.c_str = new char [length + 1];
 154                         for (i = 0; i < length; i++)
 155                                 this.c_str[i] = (char) *(value + startIndex + i);
 156                 }
 157
 158                 [CLSCompliant(false)][MonoTODO]
 159                 unsafe public String (sbyte *value, int startIndex, int length, Encoding enc)
 160                 {
 161                         // FIXME: implement me
 162                 }
 163
 164                 ~String ()
 165                 {
 166                         // FIXME: is there anything we need to do here?
 167                         /*base.Finalize ();*/
 168                 }
 169
 170                 // Properties
 171                 public int Length {
 172                         get {
 173                                 return this.length;
 174                         }
 175                 }
 176
 177                 [IndexerName("Chars")]
 178                 public char this [int index] {
 179                         get {
 180                                 if (index >= this.length)
 181                                         throw new ArgumentOutOfRangeException ();
 182
 183                                 return this.c_str[index];
 184                         }
 185                 }
 186
 187                 // Private helper methods
 188                 private static int strlen (char[] str)
 189                 {
 190                         // FIXME: if str.Length includes terminating null char, then return (str.Length - 1)
 191                         return str.Length;
 192                 }
 193
 194                 [MonoTODO]
 195                 private static char tolowerordinal (char c)
 196                 {
 197                         // FIXME: implement me
 198                         return c;
 199                 }
 200
 201                 private static bool is_lwsp (char c)
 202                 {
 203                         /* this comes from the msdn docs for String.Trim() */
 204                         if ((c >= '\x9' && c <= '\xD') || c == '\x20' || c == '\xA0' ||
 205                             (c >= '\x2000' && c <= '\x200B') || c == '\x3000' || c == '\xFEFF')
 206                                 return true;
 207                         else
 208                                 return false;
 209                 }
 210
 211                 private static int BoyerMoore (char[] haystack, string needle, int startIndex, int count)
 212                 {
 213                         /* (hopefully) Unicode-safe Boyer-Moore implementation */
 214                         int[] skiptable = new int[65536];  /* our unicode-safe skip-table */
 215                         int h, n, he, ne, hc, nc, i;
 216
 217                         if (haystack == null || needle == null)
 218                                 throw new ArgumentNullException ();
 219
 220                         /* if the search buffer is shorter than the pattern buffer, we can't match */
 221                         if (count < needle.length)
 222                                 return -1;
 223
 224                         /* return an instant match if the pattern is 0-length */
 225                         if (needle.length == 0)
 226                                 return startIndex;
 227
 228                         /* set a pointer at the end of each string */
 229                         ne = needle.length - 1;      /* position of char before '\0' */
 230                         he = startIndex + count;     /* position of last valid char */
 231
 232                         /* init the skip table with the pattern length */
 233                         nc = needle.length;
 234                         for (i = 0; i < 65536; i++)
 235                                 skiptable[i] = nc;
 236
 237                         /* set the skip value for the chars that *do* appear in the
 238                          * pattern buffer (needle) to the distance from the index to
 239                          * the end of the pattern buffer. */
 240                         for (nc = 0; nc < ne; nc++)
 241                                 skiptable[(int) needle[nc]] = ne - nc;
 242
 243                         h = startIndex;
 244                         while (count >= needle.length) {
 245                                 hc = h + needle.length - 1;  /* set the haystack compare pointer */
 246                                 nc = ne;                     /* set the needle compare pointer */
 247
 248                                 /* work our way backwards until they don't match */
 249                                 for (i = 0; nc > 0; nc--, hc--, i++)
 250                                         if (needle[nc] != haystack[hc])
 251                                                 break;
 252
 253                                 if (needle[nc] != haystack[hc]) {
 254                                         n = skiptable[(int) haystack[hc]] - i;
 255                                         h += n;
 256                                         count -= n;
 257                                 } else
 258                                         return h;
 259                         }
 260
 261                         return -1;
 262                 }
 263
 264                 // Methods
 265                 [MonoTODO]
 266                 public object Clone ()
 267                 {
 268                         // FIXME: implement me
 269                         return null;
 270                 }
 271
 272                 internal enum _StringCompareMode {
 273                         CompareDirect,
 274                         CompareCaseInsensitive,
 275                         CompareOrdinal
 276                 };
 277
 278                 internal static int _CompareGetLength (string strA, string strB)
 279                 {
 280                         if ((strA == null) || (strB == null))
 281                                         return 0;
 282                                 else
 283                                 return Math.Max (strA.Length, strB.Length);
 284                 }
 285
 286                 internal static int _CompareChar (char chrA, char chrB, CultureInfo culture,
 287                                                   _StringCompareMode mode)
 288                 {
 289                         int result = 0;
 290
 291                         switch (mode) {
 292                         case _StringCompareMode.CompareDirect:
 293                                 // FIXME: We should do a culture based comparision here,
 294                                 //        but for the moment let's do it by hand.
 295                                 //        In the microsoft runtime, uppercase letters
 296                                 //        sort after lowercase letters in the default
 297                                 //        culture.
 298                                 if (Char.IsUpper (chrA) && Char.IsLower (chrB))
 299                                 return 1;
 300                                 else if (Char.IsLower (chrA) && Char.IsUpper (chrB))
 301                                 return -1;
 302                                 result = (int) (chrA - chrB);
 303                                 break;
 304                         case _StringCompareMode.CompareCaseInsensitive:
 305                                 result = (int) (Char.ToLower (chrA) - Char.ToLower (chrB));
 306                                 break;
 307                         case _StringCompareMode.CompareOrdinal:
 308                                 result = (int) (tolowerordinal (chrA) - tolowerordinal (chrB));
 309                                 break;
 310                         }
 311
 312                         if (result == 0)
 313                                         return 0;
 314                         else if (result < 0)
 315                                         return -1;
 316                         else
 317                                 return 1;
 318                 }
 319
 320                 [MonoTODO]
 321                 internal static int _Compare (string strA, int indexA, string strB, int indexB,
 322                                               int length, CultureInfo culture,
 323                                               _StringCompareMode mode)
 324
 325                 {
 326                         int i;
 327
 328                         /* When will the hurting stop!?!? */
 329                         if (strA == null) {
 330                                 if (strB == null)
 331                                         return 0;
 332                                 else
 333                                         return -1;
 334                         } else if (strB == null)
 335                                 return 1;
 336
 337                         if (length < 0 || indexA < 0 || indexB < 0)
 338                                 throw new ArgumentOutOfRangeException ();
 339
 340                         if (indexA > strA.Length || indexB > strB.Length)
 341                                 throw new ArgumentOutOfRangeException ();
 342
 343                         // FIXME: Implement culture
 344                         if (culture != null)
 345                                 throw new NotImplementedException ();
 346
 347                         for (i = 0; i < length - 1; i++) {
 348                                 if ((indexA+i >= strA.Length) || (indexB+i >= strB.Length))
 349                                         break;
 350
 351                                 if (_CompareChar (strA[indexA+i], strB[indexB+i], culture, mode) != 0)
 352                                         break;
 353                 }
 354
 355                         if (indexA+i >= strA.Length) {
 356                                 if (indexB+i >= strB.Length)
 357                                         return 0;
 358                                 else
 359                                         return -1;
 360                         } else if (indexB+i >= strB.Length)
 361                                 return 1;
 362
 363                         return _CompareChar (strA[indexA+i], strB[indexB+i], culture, mode);
 364                 }
 365
 366
 367                 public static int Compare (string strA, string strB)
 368                 {
 369                         return Compare (strA, strB, false);
 370                 }
 371
 372                 public static int Compare (string strA, string strB, bool ignoreCase)
 373                 {
 374                         return Compare (strA, strB, ignoreCase, null);
 375                         }
 376
 377                 public static int Compare (string strA, string strB, bool ignoreCase, CultureInfo culture)
 378                 {
 379                         return Compare (strA, 0, strB, 0,
 380                                         _CompareGetLength (strA, strB),
 381                                         ignoreCase, culture);
 382                 }
 383
 384                 public static int Compare (string strA, int indexA, string strB, int indexB, int length)
 385                 {
 386                         return  Compare (strA, indexA, strB, indexB, length, false);
 387                 }
 388
 389                 public static int Compare (string strA, int indexA, string strB, int indexB,
 390                                            int length, bool ignoreCase)
 391                 {
 392                         return Compare (strA, indexA, strB, indexB, length, ignoreCase, null);
 393                 }
 394
 395                 public static int Compare (string strA, int indexA, string strB, int indexB,
 396                                            int length, bool ignoreCase, CultureInfo culture)
 397                 {
 398                         _StringCompareMode mode;
 399
 400                         mode = ignoreCase ? _StringCompareMode.CompareCaseInsensitive :
 401                                 _StringCompareMode.CompareDirect;
 402
 403                         return _Compare (strA, indexA, strB, indexB, length, culture, mode);
 404                 }
 405
 406                 public static int CompareOrdinal (string strA, string strB)
 407                 {
 408                         return CompareOrdinal (strA, 0, strB, 0, _CompareGetLength (strA, strB));
 409                         }
 410
 411                 public static int CompareOrdinal (string strA, int indexA, string strB, int indexB,
 412                                                   int length)
 413                 {
 414                         return _Compare (strA, indexA, strB, indexB, length, null,
 415                                          _StringCompareMode.CompareOrdinal);
 416                 }
 417
 418                 public int CompareTo (object obj)
 419                 {
 420                         return Compare (this, obj == null ? null : obj.ToString ());
 421                 }
 422
 423                 public int CompareTo (string str)
 424                 {
 425                         return Compare (this, str);
 426                 }
 427
 428                 public static string Concat (object arg)
 429                 {
 430                         return arg != null ? arg.ToString () : String.Empty;
 431                 }
 432
 433                 public static string Concat (params object[] args)
 434                 {
 435                         string[] strings;
 436                         char[] str;
 437                         int len, i;
 438
 439                         if (args == null)
 440                                 throw new ArgumentNullException ();
 441
 442                         strings = new string [args.Length];
 443                         len = 0;
 444                         i = 0;
 445                         foreach (object arg in args) {
 446                                 /* use Empty for each null argument */
 447                                 if (arg == null)
 448                                         strings[i] = String.Empty;
 449                                 else
 450                                         strings[i] = arg.ToString ();
 451                                 len += strings[i].length;
 452                                 i++;
 453                         }
 454
 455                         if (len == 0)
 456                                 return String.Empty;
 457
 458                         String res = new String (len);
 459                         str = res.c_str;
 460                         i = 0;
 461                         for (int j = 0; j < strings.Length; j++)
 462                                 for (int k = 0; k < strings[j].length; k++)
 463                                         str[i++] = strings[j].c_str[k];
 464
 465                         return res;
 466                 }
 467
 468                 public static string Concat (params string[] values)
 469                 {
 470                         int len, i;
 471                         char[] str;
 472
 473                         if (values == null)
 474                                 throw new ArgumentNullException ();
 475
 476                         len = 0;
 477                         foreach (string value in values)
 478                                 len += value != null ? value.Length : 0;
 479
 480                         if (len == 0)
 481                                 return String.Empty;
 482
 483                         String res = new String (len);
 484                         str = res.c_str;
 485                         i = 0;
 486                         foreach (string value in values) {
 487                                 if (value == null)
 488                                         continue;
 489
 490                                 for (int j = 0; j < value.length; j++)
 491                                         str[i++] = value.c_str[j];
 492                         }
 493
 494                         return res;
 495                 }
 496
 497                 public static string Concat (object arg0, object arg1)
 498                 {
 499                         string str0 = arg0 != null ? arg0.ToString () : String.Empty;
 500                         string str1 = arg1 != null ? arg1.ToString () : String.Empty;
 501
 502                         return Concat (str0, str1);
 503                 }
 504
 505                 public static string Concat (string str0, string str1)
 506                 {
 507                         char[] concat;
 508                         int i, j, len;
 509
 510                         if (str0 == null)
 511                                 str0 = String.Empty;
 512                         if (str1 == null)
 513                                 str1 = String.Empty;
 514
 515                         len = str0.length + str1.length;
 516                         if (len == 0)
 517                                 return String.Empty;
 518
 519                         String res = new String (len);
 520
 521                         concat = res.c_str;
 522                         for (i = 0; i < str0.length; i++)
 523                                 concat[i] = str0.c_str[i];
 524                         for (j = 0 ; j < str1.length; j++)
 525                                 concat[i + j] = str1.c_str[j];
 526
 527                         return res;
 528                 }
 529
 530                 public static string Concat (object arg0, object arg1, object arg2)
 531                 {
 532                         string str0 = arg0 != null ? arg0.ToString () : String.Empty;
 533                         string str1 = arg1 != null ? arg1.ToString () : String.Empty;
 534                         string str2 = arg2 != null ? arg2.ToString () : String.Empty;
 535
 536                         return Concat (str0, str1, str2);
 537                 }
 538
 539                 public static string Concat (string str0, string str1, string str2)
 540                 {
 541                         char[] concat;
 542                         int i, j, k, len;
 543
 544                         if (str0 == null)
 545                                 str0 = String.Empty;
 546                         if (str1 == null)
 547                                 str1 = String.Empty;
 548                         if (str2 == null)
 549                                 str2 = String.Empty;
 550
 551                         len = str0.length + str1.length + str2.length;
 552                         if (len == 0)
 553                                 return String.Empty;
 554
 555                         String res = new String (len);
 556
 557                         concat = res.c_str;
 558                         for (i = 0; i < str0.length; i++)
 559                                 concat[i] = str0.c_str[i];
 560                         for (j = 0; j < str1.length; j++)
 561                                 concat[i + j] = str1.c_str[j];
 562                         for (k = 0; k < str2.length; k++)
 563                                 concat[i + j + k] = str2.c_str[k];
 564
 565                         return res;
 566                 }
 567
 568                 public static string Concat (string str0, string str1, string str2, string str3)
 569                 {
 570                         char[] concat;
 571                         int i, j, k, l, len;
 572
 573                         if (str0 == null)
 574                                 str0 = String.Empty;
 575                         if (str1 == null)
 576                                 str1 = String.Empty;
 577                         if (str2 == null)
 578                                 str2 = String.Empty;
 579                         if (str3 == null)
 580                                 str3 = String.Empty;
 581
 582                         len = str0.length + str1.length + str2.length + str3.length;
 583                         if (len == 0)
 584                                 return String.Empty;
 585                         String res = new String (len);
 586
 587                         concat = res.c_str;
 588                         for (i = 0; i < str0.length; i++)
 589                                 concat[i] = str0.c_str[i];
 590                         for (j = 0; j < str1.length; j++)
 591                                 concat[i + j] = str1.c_str[j];
 592                         for (k = 0; k < str2.length; k++)
 593                                 concat[i + j + k] = str2.c_str[k];
 594                         for (l = 0; l < str3.length; l++)
 595                                 concat[i + j + k + l] = str3.c_str[l];
 596
 597                         return res;
 598                 }
 599
 600                 public static string Copy (string str)
 601                 {
 602                         // FIXME: how do I *copy* a string if I can only have 1 of each?
 603                         if (str == null)
 604                                 throw new ArgumentNullException ();
 605
 606                         return str;
 607                 }
 608
 609                 public void CopyTo (int sourceIndex, char[] destination, int destinationIndex, int count)
 610                 {
 611                         // LAMESPEC: should I null-terminate?
 612                         int i;
 613
 614                         if (destination == null)
 615                                 throw new ArgumentNullException ();
 616
 617                         if (sourceIndex < 0 || destinationIndex < 0 || count < 0)
 618                                 throw new ArgumentOutOfRangeException ();
 619
 620                         if (sourceIndex + count > this.length)
 621                                 throw new ArgumentOutOfRangeException ();
 622
 623                         if (destinationIndex + count > destination.Length)
 624                                 throw new ArgumentOutOfRangeException ();
 625
 626                         for (i = 0; i < count; i++)
 627                                 destination[destinationIndex + i] = this.c_str[sourceIndex + i];
 628                 }
 629
 630                 public bool EndsWith (string value)
 631                 {
 632                         bool endswith = true;
 633                         int start, i;
 634
 635                         if (value == null)
 636                                 throw new ArgumentNullException ();
 637
 638                         start = this.length - value.length;
 639                         if (start < 0)
 640                                 return false;
 641
 642                         for (i = start; i < this.length && endswith; i++)
 643                                 endswith = this.c_str[i] == value.c_str[i - start];
 644
 645                         return endswith;
 646                 }
 647
 648                 public override bool Equals (object obj)
 649                 {
 650                         if (!(obj is String))
 651                                 return false;
 652
 653                         return this == (String) obj;
 654                 }
 655
 656                 public bool Equals (string value)
 657                 {
 658                         return this == value;
 659                 }
 660
 661                 public static bool Equals (string a, string b)
 662                 {
 663                         return a == b;
 664                 }
 665
 666                 public static string Format (string format, object arg0) {
 667                         return Format (null, format, new object[] { arg0 });
 668                 }
 669
 670                 public static string Format (string format, object arg0, object arg1) {
 671                         return Format (null, format, new object[] { arg0, arg1 });
 672                 }
 673
 674                 public static string Format (string format, object arg0, object arg1, object arg2) {
 675                         return Format (null, format, new object[] { arg0, arg1, arg2 });
 676                 }
 677
 678                 public static string Format (string format, params object[] args) {
 679                         return Format (null, format, args);
 680                 }
 681
 682                 public static string Format (IFormatProvider provider, string format, params object[] args) {
 683                         if (format == null || args == null)
 684                                 throw new ArgumentNullException ();
 685
 686                         StringBuilder result = new StringBuilder ();
 687
 688                         int ptr = 0;
 689                         int start = ptr;
 690                         while (ptr < format.Length) {
 691                                 char c = format[ptr ++];
 692
 693                                 if (c == '{') {
 694                                         result.Append (format, start, ptr - start - 1);
 695
 696                                         // check for escaped open bracket
 697
 698                                         if (format[ptr] == '{') {
 699                                                 start = ptr ++;
 700                                                 continue;
 701                                         }
 702
 703                                         // parse specifier
 704
 705                                         int n, width;
 706                                         bool left_align;
 707                                         string arg_format;
 708
 709                                         ParseFormatSpecifier (format, ref ptr, out n, out width, out left_align, out arg_format);
 710                                         if (n >= args.Length)
 711                                                 throw new FormatException ("Index (zero based) must be greater than or equal to zero and less than the size of the argument list.");
 712
 713                                         // format argument
 714
 715                                         object arg = args[n];
 716
 717                                         string str;
 718                                         if (arg == null)
 719                                                 str = "";
 720                                         else if (arg is IFormattable)
 721                                                 str = ((IFormattable)arg).ToString (arg_format, provider);
 722                                         else
 723                                                 str = arg.ToString ();
 724
 725                                         // pad formatted string and append to result
 726
 727                                         if (width > str.Length) {
 728                                                 string pad = new String (' ', width - str.Length);
 729
 730                                                 if (left_align) {
 731                                                         result.Append (str);
 732                                                         result.Append (pad);
 733                                                 }
 734                                                 else {
 735                                                         result.Append (pad);
 736                                                         result.Append (str);
 737                                                 }
 738                                         }
 739                                         else
 740                                                 result.Append (str);
 741
 742                                         start = ptr;
 743                                 }
 744                                 else if (c == '}' && format[ptr] == '}') {
 745                                         result.Append (format, start, ptr - start - 1);
 746                                         start = ptr ++;
 747                                 }
 748                         }
 749
 750                         if (start < format.Length)
 751                                 result.Append (format.Substring (start));
 752
 753                         return result.ToString ();
 754                 }
 755
 756                 public CharEnumerator GetEnumerator ()
 757                 {
 758                         return new CharEnumerator (this);
 759                 }
 760
 761                 IEnumerator IEnumerable.GetEnumerator ()
 762                 {
 763                         return new CharEnumerator (this);
 764                 }
 765
 766                 public override int GetHashCode ()
 767                 {
 768                         int h = 0;
 769                         int i;
 770                         for (i = 0; i < length; ++i)
 771                                 h = (h << 5) - h + c_str [i];
 772                         return h;
 773                 }
 774
 775                 public TypeCode GetTypeCode ()
 776                 {
 777                         return TypeCode.String;
 778                 }
 779
 780                 public int IndexOf (char value)
 781                 {
 782                         return IndexOf (value, 0, this.length);
 783                 }
 784
 785                 public int IndexOf (string value)
 786                 {
 787                         return IndexOf (value, 0, this.length);
 788                 }
 789
 790                 public int IndexOf (char value, int startIndex)
 791                 {
 792                         return IndexOf (value, startIndex, this.length - startIndex);
 793                 }
 794
 795                 public int IndexOf (string value, int startIndex)
 796                 {
 797                         return IndexOf (value, startIndex, this.length - startIndex);
 798                 }
 799
 800                 public int IndexOf (char value, int startIndex, int count)
 801                 {
 802                         int i;
 803
 804                         if (startIndex < 0 || count < 0 || startIndex + count > this.length)
 805                                 throw new ArgumentOutOfRangeException ();
 806
 807                         for (i = startIndex; i - startIndex < count; i++)
 808                                 if (this.c_str[i] == value)
 809                                         return i;
 810
 811                         return -1;
 812                 }
 813
 814                 public int IndexOf (string value, int startIndex, int count)
 815                 {
 816                         if (value == null)
 817                                 throw new ArgumentNullException ();
 818
 819                         if (startIndex < 0 || count < 0 || startIndex + count > this.length)
 820                                 throw new ArgumentOutOfRangeException ();
 821
 822                         return BoyerMoore (this.c_str, value, startIndex, count);
 823 #if XXX
 824                         int i;
 825                         for (i = startIndex; i - startIndex + value.Length <= count; ) {
 826                                 if (this.c_str[i] == value[0]) {
 827                                         bool equal = true;
 828                                         int j, nexti = 0;
 829
 830                                         for (j = 1; equal && j < value.Length; j++) {
 831                                                 equal = this.c_str[i + j] == value[j];
 832                                                 if (this.c_str[i + j] == value[0] && nexti == 0)
 833                                                         nexti = i + j;
 834                                         }
 835
 836                                         if (equal)
 837                                                 return i;
 838
 839                                         if (nexti != 0)
 840                                                 i = nexti;
 841                                         else
 842                                                 i += j;
 843                                 } else
 844                                         i++;
 845                         }
 846
 847                         return -1;
 848 #endif
 849                 }
 850
 851                 public int IndexOfAny (char[] values)
 852                 {
 853                         return IndexOfAny (values, 0, this.length);
 854                 }
 855
 856                 public int IndexOfAny (char[] values, int startIndex)
 857                 {
 858                         return IndexOfAny (values, startIndex, this.length - startIndex);
 859                 }
 860
 861                 public int IndexOfAny (char[] values, int startIndex, int count)
 862                 {
 863                         if (values == null)
 864                                 throw new ArgumentNullException ();
 865
 866                         if (startIndex < 0 || count < 0 || startIndex + count > this.length)
 867                                 throw new ArgumentOutOfRangeException ();
 868
 869                         for (int i = startIndex; i < startIndex + count; i++) {
 870                                 for (int j = 0; j < strlen (values); j++) {
 871                                         if (this.c_str[i] == values[j])
 872                                                 return i;
 873                                 }
 874                         }
 875
 876                         return -1;
 877                 }
 878
 879                 public string Insert (int startIndex, string value)
 880                 {
 881                         char[] str;
 882                         int i, j;
 883
 884                         if (value == null)
 885                                 throw new ArgumentNullException ();
 886
 887                         if (startIndex < 0 || startIndex > this.length)
 888                                 throw new ArgumentOutOfRangeException ();
 889
 890                         String res = new String (value.length + this.length);
 891
 892                         str = res.c_str;
 893                         for (i = 0; i < startIndex; i++)
 894                                 str[i] = this.c_str[i];
 895                         for (j = 0; j < value.length; j++)
 896                                 str[i + j] = value.c_str[j];
 897                         for ( ; i < this.length; i++)
 898                                 str[i + j] = this.c_str[i];
 899
 900                         return res;
 901                 }
 902
 903                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
 904                 internal extern static string _Intern (string str);
 905
 906                 public static string Intern (string str)
 907                 {
 908                         if (str == null)
 909                                 throw new ArgumentNullException ();
 910
 911                         return _Intern (str);
 912                 }
 913
 914                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
 915                 internal extern static string _IsInterned (string str);
 916
 917                 public static string IsInterned (string str)
 918                 {
 919                         if (str == null)
 920                                 throw new ArgumentNullException ();
 921
 922                         return _IsInterned (str);
 923                 }
 924
 925                 public static string Join (string separator, string[] value)
 926                 {
 927                         if (value == null)
 928                                 throw new ArgumentNullException ();
 929
 930                         return Join (separator, value, 0, value.Length);
 931                 }
 932
 933                 public static string Join (string separator, string[] value, int startIndex, int count)
 934                 {
 935                         // LAMESPEC: msdn doesn't specify what happens when separator is null
 936                         int len, i, j, used;
 937                         char[] str;
 938
 939                         if (separator == null || value == null)
 940                                 throw new ArgumentNullException ();
 941
 942                         if (startIndex + count > value.Length)
 943                                 throw new ArgumentOutOfRangeException ();
 944
 945                         len = 0;
 946                         for (i = startIndex, used = 0; used < count; i++, used++) {
 947                                 if (i != startIndex)
 948                                         len += separator.length;
 949
 950                                 len += value[i].length;
 951                         }
 952
 953                         // We have no elements to join?
 954                         if (i == startIndex)
 955                                 return String.Empty;
 956
 957                         String res = new String (len);
 958
 959                         str = res.c_str;
 960                         for (i = 0; i < value[startIndex].length; i++)
 961                                 str[i] = value[startIndex][i];
 962
 963                         used = 1;
 964                         for (j = startIndex + 1; used < count; j++, used++) {
 965                                 int k;
 966
 967                                 for (k = 0; k < separator.length; k++)
 968                                         str[i++] = separator.c_str[k];
 969                                 for (k = 0; k < value[j].length; k++)
 970                                         str[i++] = value[j].c_str[k];
 971                         }
 972
 973                         return res;
 974                 }
 975
 976                 public int LastIndexOf (char value)
 977                 {
 978                         int i = this.length;
 979                         if (i == 0)
 980                                 return -1;
 981                         --i;
 982                         for (; i >= 0; i--) {
 983                                 if (this.c_str[i] == value)
 984                                         return i;
 985                         }
 986
 987                         return -1;
 988                 }
 989
 990                 public int LastIndexOf (string value)
 991                 {
 992                         if (value == null)
 993                                 throw new ArgumentNullException ();
 994                         if (value.length == 0)
 995                                 return 0;
 996                         if (this.length == 0)
 997                                 return -1;
 998
 999                         return LastIndexOf (value, this.length - 1, this.length);
1000                 }
1001
1002                 public int LastIndexOf (char value, int startIndex)
1003                 {
1004                         if (startIndex < 0 || startIndex >= this.length)
1005                                 throw new ArgumentOutOfRangeException ();
1006
1007                         for (int i = startIndex; i >= 0; i--) {
1008                                 if (this.c_str[i] == value)
1009                                         return i;
1010                         }
1011
1012                         return -1;
1013                 }
1014
1015                 public int LastIndexOf (string value, int startIndex)
1016                 {
1017                         return LastIndexOf (value, startIndex, startIndex + 1);
1018                 }
1019
1020                 public int LastIndexOf (char value, int startIndex, int count)
1021                 {
1022                         if (startIndex < 0 || count < 0)
1023                                 throw new ArgumentOutOfRangeException ();
1024
1025                         if (startIndex >= this.length || startIndex - count + 1 < 0)
1026                                 throw new ArgumentOutOfRangeException ();
1027
1028                         for (int i = startIndex; i > startIndex - count; i--) {
1029                                 if (this.c_str[i] == value)
1030                                         return i;
1031                         }
1032
1033                         return -1;
1034                 }
1035
1036                 public int LastIndexOf (string value, int startIndex, int count)
1037                 {
1038                         // startIndex points to the end of value, ie. we're searching backwards.
1039                         int i, len;
1040
1041                         if (value == null)
1042                                 throw new ArgumentNullException ();
1043
1044                         if (startIndex < 0 || startIndex > this.length)
1045                                 throw new ArgumentOutOfRangeException ();
1046
1047                         if (count < 0 || startIndex - count + 1 < 0)
1048                                 throw new ArgumentOutOfRangeException ();
1049
1050                         if (value.length > startIndex)
1051                                 return -1;
1052
1053                         if (value == String.Empty)
1054                                 return startIndex;
1055
1056                         if (startIndex == this.length)
1057                                 startIndex--;
1058
1059                         // FIXME: use a reversed-unicode-safe-Boyer-Moore?
1060                         len = value.length - 1;
1061                         for (i = startIndex; i > startIndex - count; i--) {
1062
1063                                 if (this.c_str[i] == value.c_str[len]) {
1064                                         bool equal = true;
1065                                         int j;
1066
1067                                         for (j = 0; equal && j < len; j++)
1068                                                 equal = this.c_str[i - j] == value.c_str[len - j];
1069
1070                                         if (equal)
1071                                                 return i - j;
1072                                 }
1073                         }
1074
1075                         return -1;
1076                 }
1077
1078                 public int LastIndexOfAny (char[] values)
1079                 {
1080                         return LastIndexOfAny (values, this.length - 1, this.length);
1081                 }
1082
1083                 public int LastIndexOfAny (char[] values, int startIndex)
1084                 {
1085                         return LastIndexOfAny (values, startIndex, startIndex + 1);
1086                 }
1087
1088                 public int LastIndexOfAny (char[] values, int startIndex, int count)
1089                 {
1090                         int i;
1091
1092                         if (values == null)
1093                                 throw new ArgumentNullException ();
1094
1095                         if (startIndex < 0 || count < 0 || startIndex - count + 1 < 0)
1096                                 throw new ArgumentOutOfRangeException ();
1097
1098                         for (i = startIndex; i > startIndex - count; i--) {
1099                                 for (int j = 0; j < strlen (values); j++) {
1100                                         if (this.c_str[i] == values[j])
1101                                                 return i;
1102                                 }
1103                         }
1104
1105                         return -1;
1106                 }
1107
1108                 public string PadLeft (int totalWidth)
1109                 {
1110                         return PadLeft (totalWidth, ' ');
1111                 }
1112
1113                 public string PadLeft (int totalWidth, char padChar)
1114                 {
1115                         char[] str;
1116                         int i, j;
1117
1118                         if (totalWidth < 0)
1119                                 throw new ArgumentException ();
1120
1121                         str = new char [totalWidth > this.length ? totalWidth : this.length];
1122                         for (i = 0; i < totalWidth - this.length; i++)
1123                                 str[i] = padChar;
1124
1125                         for (j = 0; j < this.length; i++, j++)
1126                                 str[i] = this.c_str[j];
1127
1128                         return new String (str);
1129                 }
1130
1131                 public string PadRight (int totalWidth)
1132                 {
1133                         return PadRight (totalWidth, ' ');
1134                 }
1135
1136                 public string PadRight (int totalWidth, char padChar)
1137                 {
1138                         char[] str;
1139                         int i;
1140
1141                         if (totalWidth < 0)
1142                                 throw new ArgumentException ();
1143
1144                         str = new char [totalWidth > this.length ? totalWidth : this.length];
1145                         for (i = 0; i < this.length; i++)
1146                                 str[i] = this.c_str[i];
1147
1148                         for ( ; i < str.Length; i++)
1149                                 str[i] = padChar;
1150
1151                         return new String (str);
1152                 }
1153
1154                 public string Remove (int startIndex, int count)
1155                 {
1156                         char[] str;
1157                         int i, j, len;
1158
1159                         if (startIndex < 0 || count < 0 || startIndex + count > this.length)
1160                                 throw new ArgumentOutOfRangeException ();
1161
1162                         len = this.length - count;
1163                         if (len == 0)
1164                                 return String.Empty;
1165
1166                         String res = new String (len);
1167                         str = res.c_str;
1168                         for (i = 0; i < startIndex; i++)
1169                                 str[i] = this.c_str[i];
1170                         for (j = i + count; j < this.length; j++)
1171                                 str[i++] = this.c_str[j];
1172
1173                         return res;
1174                 }
1175
1176                 public string Replace (char oldChar, char newChar)
1177                 {
1178                         char[] str;
1179                         int i;
1180
1181                         String res = new String (length);
1182                         str = res.c_str;
1183                         for (i = 0; i < this.length; i++) {
1184                                 if (this.c_str[i] == oldChar)
1185                                         str[i] = newChar;
1186                                 else
1187                                         str[i] = this.c_str[i];
1188                         }
1189
1190                         return res;
1191                 }
1192
1193                 public string Replace (string oldValue, string newValue)
1194                 {
1195                         // If newValue is null, oldValue is removed.
1196                         int index, len, i, j, newlen;
1197                         string thestring;
1198                         char[] str;
1199
1200                         if (oldValue == null)
1201                                 throw new ArgumentNullException ();
1202
1203                         thestring = Substring (0, this.length);
1204                         index = 0;
1205
1206                         // Runs until all occurences of oldValue have been replaced.
1207                         while (true) {
1208                                 // Use IndexOf in case I later rewrite it to use Boyer-Moore
1209                                 index = thestring.IndexOf (oldValue, index);
1210
1211                                 if (index == -1)
1212                                         return thestring;
1213
1214                                 newlen = (newValue == null) ? 0 : newValue.length;
1215                                 len = thestring.length - oldValue.length + newlen;
1216
1217                                 if (len == 0)
1218                                         return String.Empty;
1219
1220                                 String res = new String (len);
1221                                 str = res.c_str;
1222                                 for (i = 0; i < index; i++)
1223                                         str[i] = thestring.c_str[i];
1224                                 for (j = 0; j < newlen; j++)
1225                                         str[i++] = newValue[j];
1226                                 for (j = index + oldValue.length; j < thestring.length; j++)
1227                                         str[i++] = thestring.c_str[j];
1228
1229                                 // Increment index, we're already done replacing until this index.
1230                                 thestring = res;
1231                                 index += newlen;
1232                         }
1233                 }
1234
1235                 private int splitme (char[] separators, int startIndex)
1236                 {
1237                         /* this is basically a customized IndexOfAny() for the Split() methods */
1238                         for (int i = startIndex; i < this.length; i++) {
1239                                 if (separators != null) {
1240                                         foreach (char sep in separators) {
1241                                                 if (this.c_str[i] == sep)
1242                                                         return i - startIndex;
1243                                         }
1244                                 } else if (is_lwsp (this.c_str[i])) {
1245                                         return i - startIndex;
1246                                 }
1247                         }
1248
1249                         return -1;
1250                 }
1251
1252                 public string[] Split (params char[] separator)
1253                 {
1254                         /**
1255                          * split:
1256                          * @separator: delimiting chars or null to split on whtspc
1257                          *
1258                          * Returns: 1. An array consisting of a single
1259                          * element (@this) if none of the delimiting
1260                          * chars appear in @this. 2. An array of
1261                          * substrings which are delimited by one of
1262                          * the separator chars. 3. An array of
1263                          * substrings separated by whitespace if
1264                          * @separator is null. The Empty string should
1265                          * be returned wherever 2 delimiting chars are
1266                          * adjacent.
1267                          **/
1268                         // FIXME: would using a Queue be better?
1269                         string[] strings;
1270                         ArrayList list;
1271                         int index, len;
1272
1273                         list = new ArrayList ();
1274                         for (index = 0, len = 0; index < this.length; index += len + 1) {
1275                                 len = splitme (separator, index);
1276                                 len = len > -1 ? len : this.length - index;
1277                                 if (len == 0) {
1278                                         list.Add (String.Empty);
1279                                 } else {
1280                                         char[] str;
1281                                         int i;
1282
1283                                         str = new char [len];
1284                                         for (i = 0; i < len; i++)
1285                                                 str[i] = this.c_str[index + i];
1286
1287                                         list.Add (new String (str));
1288                                 }
1289                         }
1290
1291                         strings = new string [list.Count];
1292                         if (list.Count == 1) {
1293                                 /* special case for an array holding @this */
1294                                 strings[0] = this;
1295                         } else {
1296                                 for (index = 0; index < list.Count; index++)
1297                                         strings[index] = (string) list[index];
1298                         }
1299
1300                         return strings;
1301                 }
1302
1303                 public string[] Split (char[] separator, int maxCount)
1304                 {
1305                         // FIXME: would using Queue be better than ArrayList?
1306                         string[] strings;
1307                         ArrayList list;
1308                         int index, len, used;
1309
1310                         if (maxCount == 0)
1311                                 return new string[0];
1312                         else if (maxCount < 0)
1313                                 throw new ArgumentOutOfRangeException ();
1314
1315                         used = 0;
1316                         list = new ArrayList ();
1317                         for (index = 0, len = 0; index < this.length && used < maxCount-1; index += len + 1) {
1318                                 len = splitme (separator, index);
1319                                 len = len > -1 ? len : this.length - index;
1320                                 if (len == 0) {
1321                                         list.Add (String.Empty);
1322                                 } else {
1323                                         char[] str;
1324                                         int i;
1325
1326                                         str = new char [len];
1327                                         for (i = 0; i < len; i++)
1328                                                 str[i] = this.c_str[index + i];
1329
1330                                         list.Add (new String (str));
1331                                 }
1332                                 used++;
1333                         }
1334
1335                         /* fit the remaining chunk of the @this into it's own element */
1336                         if (index < this.length - 1) {
1337                                 char[] str;
1338                                 int i;
1339
1340                                 str = new char [this.length - index];
1341                                 for (i = index; i < this.length; i++)
1342                                         str[i - index] = this.c_str[i];
1343
1344                                 list.Add (new String (str));
1345                         }
1346
1347                         strings = new string [list.Count];
1348                         if (list.Count == 1) {
1349                                 /* special case for an array holding @this */
1350                                 strings[0] = this;
1351                         } else {
1352                                 for (index = 0; index < list.Count; index++)
1353                                         strings[index] = (string) list[index];
1354                         }
1355
1356                         return strings;
1357                 }
1358
1359                 public bool StartsWith (string value)
1360                 {
1361                         bool startswith = true;
1362                         int i;
1363
1364                         if (value == null)
1365                                 throw new ArgumentNullException ();
1366
1367                         if (value.length > this.length)
1368                                 return false;
1369
1370                         for (i = 0; i < value.length && startswith; i++)
1371                                 startswith = startswith && value.c_str[i] == this.c_str[i];
1372
1373                         return startswith;
1374                 }
1375
1376                 public string Substring (int startIndex)
1377                 {
1378                         char[] str;
1379                         int i, len;
1380
1381                         if (startIndex < 0 || startIndex > this.length)
1382                                 throw new ArgumentOutOfRangeException ();
1383
1384                         len = this.length - startIndex;
1385                         if (len == 0)
1386                                 return String.Empty;
1387                         String res = new String (len);
1388                         str = res.c_str;
1389                         for (i = startIndex; i < this.length; i++)
1390                                 str[i - startIndex] = this.c_str[i];
1391
1392                         return res;
1393                 }
1394
1395                 public string Substring (int startIndex, int length)
1396                 {
1397                         char[] str;
1398                         int i;
1399
1400                         if (startIndex < 0 || length < 0 || startIndex + length > this.length)
1401                                 throw new ArgumentOutOfRangeException ();
1402
1403                         if (length == 0)
1404                                 return String.Empty;
1405
1406                         String res = new String (length);
1407                         str = res.c_str;
1408                         for (i = startIndex; i < startIndex + length; i++)
1409                                 str[i - startIndex] = this.c_str[i];
1410
1411                         return res;
1412                 }
1413
1414                 bool IConvertible.ToBoolean (IFormatProvider provider)
1415                 {
1416                         return Convert.ToBoolean (this);
1417                 }
1418
1419                 byte IConvertible.ToByte (IFormatProvider provider)
1420                 {
1421                         return Convert.ToByte (this);
1422                 }
1423
1424                 char IConvertible.ToChar (IFormatProvider provider)
1425                 {
1426                         return Convert.ToChar (this);
1427                 }
1428
1429                 public char[] ToCharArray ()
1430                 {
1431                         return ToCharArray (0, this.length);
1432                 }
1433
1434                 public char[] ToCharArray (int startIndex, int length)
1435                 {
1436                         char[] chars;
1437                         int i;
1438
1439                         if (startIndex < 0 || length < 0 || startIndex + length > this.length)
1440                                 throw new ArgumentOutOfRangeException ();
1441
1442                         chars = new char [length];
1443                         for (i = startIndex; i < length; i++)
1444                                 chars[i - startIndex] = this.c_str[i];
1445
1446                         return chars;
1447                 }
1448
1449                 DateTime IConvertible.ToDateTime (IFormatProvider provider)
1450                 {
1451                         return Convert.ToDateTime (this);
1452                 }
1453
1454                 decimal IConvertible.ToDecimal (IFormatProvider provider)
1455                 {
1456                         return Convert.ToDecimal (this);
1457                 }
1458
1459                 double IConvertible.ToDouble (IFormatProvider provider)
1460                 {
1461                         return Convert.ToDouble (this);
1462                 }
1463
1464                 short IConvertible.ToInt16 (IFormatProvider provider)
1465                 {
1466                         return Convert.ToInt16 (this);
1467                 }
1468
1469                 int IConvertible.ToInt32 (IFormatProvider provider)
1470                 {
1471                         return Convert.ToInt32 (this);
1472                 }
1473
1474                 long IConvertible.ToInt64 (IFormatProvider provider)
1475                 {
1476                         return Convert.ToInt64 (this);
1477                 }
1478
1479                 public string ToLower ()
1480                 {
1481                         char[] str;
1482                         int i;
1483
1484                         String res = new String (length);
1485                         str = res.c_str;
1486                         for (i = 0; i < this.length; i++)
1487                                 str[i] = Char.ToLower (this.c_str[i]);
1488
1489                         return res;
1490                 }
1491
1492                 [MonoTODO]
1493                 public string ToLower (CultureInfo culture)
1494                 {
1495                         // FIXME: implement me
1496                         throw new NotImplementedException ();
1497
1498                 }
1499
1500                 [CLSCompliant(false)]
1501                 sbyte IConvertible.ToSByte (IFormatProvider provider)
1502                 {
1503                         return Convert.ToSByte (this);
1504                 }
1505
1506                 float IConvertible.ToSingle (IFormatProvider provider)
1507                 {
1508                         return Convert.ToSingle (this);
1509                 }
1510
1511                 public override string ToString ()
1512                 {
1513                         return this;
1514                 }
1515
1516                 string IConvertible.ToString (IFormatProvider format)
1517                 {
1518                         return this;
1519                 }
1520
1521                 object IConvertible.ToType (Type conversionType, IFormatProvider provider)
1522                 {
1523                         return Convert.ToType (this, conversionType,  provider);
1524                 }
1525
1526                 [CLSCompliant(false)]
1527                 ushort IConvertible.ToUInt16 (IFormatProvider provider)
1528                 {
1529                         return Convert.ToUInt16 (this);
1530                 }
1531
1532                 [CLSCompliant(false)]
1533                 uint IConvertible.ToUInt32 (IFormatProvider provider)
1534                 {
1535                         return Convert.ToUInt32 (this);
1536                 }
1537
1538                 [CLSCompliant(false)]
1539                 ulong IConvertible.ToUInt64 (IFormatProvider provider)
1540                 {
1541                         return Convert.ToUInt64 (this);
1542                 }
1543
1544                 public string ToUpper ()
1545                 {
1546                         char[] str;
1547                         int i;
1548
1549                         String res = new String (length);
1550                         str = res.c_str;
1551                         for (i = 0; i < this.length; i++)
1552                                 str[i] = Char.ToUpper (this.c_str[i]);
1553
1554                         return res;
1555                 }
1556
1557                 [MonoTODO]
1558                 public string ToUpper (CultureInfo culture)
1559                 {
1560                         // FIXME: implement me
1561                         throw new NotImplementedException ();
1562                 }
1563
1564                 public string Trim ()
1565                 {
1566                         return Trim (null);
1567                 }
1568
1569                 public string Trim (params char[] trimChars)
1570                 {
1571                         int begin, end;
1572                         bool matches = false;
1573
1574                         for (begin = 0; begin < this.length; begin++) {
1575                                 if (trimChars != null) {
1576                                         matches = false;
1577                                         foreach (char c in trimChars) {
1578                                                 matches = this.c_str[begin] == c;
1579                                                 if (matches)
1580                                                         break;
1581                                         }
1582                                         if (matches)
1583                                                 continue;
1584                                 } else {
1585                                         matches = is_lwsp (this.c_str[begin]);
1586                                         if (matches)
1587                                                 continue;
1588                                 }
1589                                 break;
1590                         }
1591
1592                         for (end = this.length - 1; end > begin; end--) {
1593                                 if (trimChars != null) {
1594                                         matches = false;
1595                                         foreach (char c in trimChars) {
1596                                                 matches = this.c_str[end] == c;
1597                                                 if (matches)
1598                                                         break;
1599                                         }
1600                                         if (matches)
1601                                                 continue;
1602                                 } else {
1603                                         matches = is_lwsp (this.c_str[end]);
1604                                         if (matches)
1605                                                 continue;
1606                                 }
1607                                 break;
1608                         }
1609                         end++;
1610
1611                         if (begin >= end)
1612                                 return String.Empty;
1613
1614                         return Substring (begin, end - begin);
1615                 }
1616
1617                 public string TrimEnd (params char[] trimChars)
1618                 {
1619                         bool matches = true;
1620                         int end;
1621
1622                         for (end = this.length - 1; matches && end > 0; end--) {
1623
1624                                 if (trimChars != null) {
1625                                         matches = false;
1626                                         foreach (char c in trimChars) {
1627                                                 matches = this.c_str[end] == c;
1628                                                 if (matches)
1629                                                         break;
1630                                         }
1631                                 } else {
1632                                         matches = is_lwsp (this.c_str[end]);
1633                                 }
1634
1635                                 if (!matches)
1636                                         return Substring (0, end+1);
1637                         }
1638
1639                         if (end == 0)
1640                                 return String.Empty;
1641
1642                         return Substring (0, end);
1643                 }
1644
1645                 public string TrimStart (params char[] trimChars)
1646                 {
1647                         bool matches = true;
1648                         int begin;
1649
1650                         for (begin = 0; matches && begin < this.length; begin++) {
1651                                 if (trimChars != null) {
1652                                         matches = false;
1653                                         foreach (char c in trimChars) {
1654                                                 matches = this.c_str[begin] == c;
1655                                                 if (matches)
1656                                                         break;
1657                                         }
1658                                 } else {
1659                                         matches = is_lwsp (this.c_str[begin]);
1660                                 }
1661
1662                                 if (!matches)
1663                                         return Substring (begin, this.length - begin);
1664                         }
1665
1666                                 return String.Empty;
1667                 }
1668
1669                 // Operators
1670                 public static bool operator ==(string a, string b)
1671                 {
1672                         if ((object)a == null) {
1673                                 if ((object)b == null)
1674                                         return true;
1675                                 return false;
1676                         }
1677                         if ((object)b == null)
1678                                 return false;
1679
1680                         if (a.length != b.length)
1681                                 return false;
1682
1683                         int l = a.length;
1684                         for (int i = 0; i < l; i++)
1685                                 if (a.c_str[i] != b.c_str[i])
1686                                         return false;
1687
1688                         return true;
1689                 }
1690
1691                 public static bool operator !=(string a, string b)
1692                 {
1693                         return !(a == b);
1694                 }
1695
1696                 // private
1697
1698                 private static void ParseFormatSpecifier (string str, ref int ptr, out int n, out int width, out bool left_align, out string format) {
1699                         // parses format specifier of form:
1700                         //   N,[[-]M][:F]}
1701                         //
1702                         // where:
1703
1704                         try {
1705                                 // N = argument number (non-negative integer)
1706
1707                                 n = ParseDecimal (str, ref ptr);
1708                                 if (n < 0)
1709                                         throw new FormatException ("Input string was not in correct format.");
1710
1711                                 // M = width (non-negative integer)
1712
1713                                 if (str[ptr] == ',') {
1714                                         left_align = (str[++ ptr] == '-');
1715                                         if (left_align)
1716                                                 ++ ptr;
1717
1718                                         width = ParseDecimal (str, ref ptr);
1719                                         if (width < 0)
1720                                                 throw new FormatException ("Input string was not in correct format.");
1721                                 }
1722                                 else {
1723                                         width = 0;
1724                                         left_align = false;
1725                                 }
1726
1727                                 // F = argument format (string)
1728
1729                                 if (str[ptr] == ':') {
1730                                         int start = ++ ptr;
1731                                         while (str[ptr] != '}')
1732                                                 ++ ptr;
1733
1734                                         format = str.Substring (start, ptr - start);
1735                                 }
1736                                 else
1737                                         format = null;
1738
1739                                 if (str[ptr ++] != '}')
1740                                         throw new FormatException ("Input string was not in correct format.");
1741                         }
1742                         catch (IndexOutOfRangeException) {
1743                                 throw new FormatException ("Input string was not in correct format.");
1744                         }
1745                 }
1746
1747                 private static int ParseDecimal (string str, ref int ptr) {
1748                         int p = ptr;
1749                         int n = 0;
1750                         while (true) {
1751                                 char c = str[p];
1752                                 if (c < '0' || '9' < c)
1753                                         break;
1754
1755                                 n = n * 10 + c - '0';
1756                                 ++ p;
1757                         }
1758
1759                         if (p == ptr)
1760                                 return -1;
1761
1762                         ptr = p;
1763                         return n;
1764                 }
1765         }
1766 }