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         [Serializable]
  35         public sealed class String : IComparable, ICloneable, IConvertible, IEnumerable {
  36                 public static readonly string Empty = "";
  37                 private char[] c_str;
  38                 private int length;
  39
  40                 // Constructors
  41
  42                 internal String (int storage)
  43                 {
  44                         if (storage < 0)
  45                                 throw new ArgumentOutOfRangeException ();
  46                         length = storage;
  47                         c_str = new char [storage];
  48                 }
  49
  50                 [CLSCompliant(false)]
  51                 unsafe public String (char *value)
  52                 {
  53                         int i;
  54
  55                         // FIXME: can I do value.Length here?
  56                         if (value == null) {
  57                                 this.length = 0;
  58                         } else {
  59                                 for (i = 0; *(value + i) != '\0'; i++);
  60                                 this.length = i;
  61                         }
  62
  63                         this.c_str = new char [this.length + 1];
  64                         for (i = 0; i < this.length; i++)
  65                                 this.c_str[i] = *(value + i);
  66                 }
  67
  68                 public String (char[] value)
  69                 {
  70                         int i;
  71
  72                         // FIXME: value.Length includes the terminating null char?
  73                         this.length = value != null ? strlen (value): 0;
  74                         this.c_str = new char [this.length + 1];
  75                         for (i = 0; i < this.length; i++)
  76                                 this.c_str[i] = value[i];
  77                 }
  78
  79                 [CLSCompliant(false)]
  80                 unsafe public String (sbyte *value)
  81                 {
  82                         // FIXME: consider unicode?
  83                         int i;
  84
  85                         // FIXME: can I do value.Length here? */
  86                         if (value == null) {
  87                                 this.length = 0;
  88                         } else {
  89                                 for (i = 0; *(value + i) != '\0'; i++);
  90                                 this.length = i;
  91                         }
  92
  93                         this.c_str = new char [this.length + 1];
  94                         for (i = 0; i < this.length; i++)
  95                                 this.c_str[i] = (char) *(value + i);
  96                 }
  97
  98                 public String (char c, int count)
  99                 {
 100                         int i;
 101
 102                         this.length = count;
 103                         this.c_str = new char [count + 1];
 104                         for (i = 0; i < count; i++)
 105                                 this.c_str[i] = c;
 106                 }
 107
 108                 [CLSCompliant(false)]
 109                 unsafe public String (char *value, int startIndex, int length)
 110                 {
 111                         int i;
 112
 113                         if (value == null && startIndex != 0 && length != 0)
 114                                 throw new ArgumentNullException ();
 115
 116                         if (startIndex < 0 || length < 0)
 117                                 throw new ArgumentOutOfRangeException ();
 118
 119                         this.length = length;
 120                         this.c_str = new char [length + 1];
 121                         for (i = 0; i < length; i++)
 122                                 this.c_str[i] = *(value + startIndex + i);
 123                 }
 124
 125                 public String (char[] value, int startIndex, int length)
 126                 {
 127                         int i;
 128
 129                         if (value == null && startIndex != 0 && length != 0)
 130                                 throw new ArgumentNullException ();
 131
 132                         if (startIndex < 0 || length < 0)
 133                                 throw new ArgumentOutOfRangeException ();
 134
 135                         this.length = length;
 136                         this.c_str = new char [length + 1];
 137                         for (i = 0; i < length; i++)
 138                                 this.c_str[i] = value[startIndex + i];
 139                 }
 140
 141                 [CLSCompliant(false)]
 142                 unsafe public String (sbyte *value, int startIndex, int length)
 143                 {
 144                         // FIXME: consider unicode?
 145                         int i;
 146
 147                         if (value == null && startIndex != 0 && length != 0)
 148                                 throw new ArgumentNullException ();
 149
 150                         if (startIndex < 0 || length < 0)
 151                                 throw new ArgumentOutOfRangeException ();
 152
 153                         this.length = length;
 154                         this.c_str = new char [length + 1];
 155                         for (i = 0; i < length; i++)
 156                                 this.c_str[i] = (char) *(value + startIndex + i);
 157                 }
 158
 159                 [CLSCompliant(false)][MonoTODO]
 160                 unsafe public String (sbyte *value, int startIndex, int length, Encoding enc)
 161                 {
 162                         // FIXME: implement me
 163                 }
 164
 165                 // FIXME: is there anything we need to do here?
 166                 /*
 167                 ~String ()
 168                 {
 169                         base.Finalize ();
 170                 }
 171                 */
 172
 173                 // Properties
 174                 public int Length {
 175                         get {
 176                                 return this.length;
 177                         }
 178                 }
 179
 180                 [IndexerName("Chars")]
 181                 public char this [int index] {
 182                         get {
 183                                 if (index >= this.length)
 184                                         throw new ArgumentOutOfRangeException ();
 185
 186                                 return this.c_str[index];
 187                         }
 188                 }
 189
 190                 // Private helper methods
 191                 private static int strlen (char[] str)
 192                 {
 193                         // FIXME: if str.Length includes terminating null char, then return (str.Length - 1)
 194                         return str.Length;
 195                 }
 196
 197                 [MonoTODO]
 198                 private static char tolowerordinal (char c)
 199                 {
 200                         // FIXME: implement me
 201                         return c;
 202                 }
 203
 204                 private static bool is_lwsp (char c)
 205                 {
 206                         /* this comes from the msdn docs for String.Trim() */
 207                         if ((c >= '\x9' && c <= '\xD') || c == '\x20' || c == '\xA0' ||
 208                             (c >= '\x2000' && c <= '\x200B') || c == '\x3000' || c == '\xFEFF')
 209                                 return true;
 210                         else
 211                                 return false;
 212                 }
 213
 214                 private static int BoyerMoore (char[] haystack, string needle, int startIndex, int count)
 215                 {
 216                         /* (hopefully) Unicode-safe Boyer-Moore implementation */
 217                         int[] skiptable = new int[65536];  /* our unicode-safe skip-table */
 218                         int h, n, he, ne, hc, nc, i;
 219
 220                         if (haystack == null || needle == null)
 221                                 throw new ArgumentNullException ();
 222
 223                         /* if the search buffer is shorter than the pattern buffer, we can't match */
 224                         if (count < needle.length)
 225                                 return -1;
 226
 227                         /* return an instant match if the pattern is 0-length */
 228                         if (needle.length == 0)
 229                                 return startIndex;
 230
 231                         /* set a pointer at the end of each string */
 232                         ne = needle.length - 1;      /* position of char before '\0' */
 233                         he = startIndex + count;     /* position of last valid char */
 234
 235                         /* init the skip table with the pattern length */
 236                         nc = needle.length;
 237                         for (i = 0; i < 65536; i++)
 238                                 skiptable[i] = nc;
 239
 240                         /* set the skip value for the chars that *do* appear in the
 241                          * pattern buffer (needle) to the distance from the index to
 242                          * the end of the pattern buffer. */
 243                         for (nc = 0; nc < ne; nc++)
 244                                 skiptable[(int) needle[nc]] = ne - nc;
 245
 246                         h = startIndex;
 247                         while (count >= needle.length) {
 248                                 hc = h + needle.length - 1;  /* set the haystack compare pointer */
 249                                 nc = ne;                     /* set the needle compare pointer */
 250
 251                                 /* work our way backwards until they don't match */
 252                                 for (i = 0; nc > 0; nc--, hc--, i++)
 253                                         if (needle[nc] != haystack[hc])
 254                                                 break;
 255
 256                                 if (needle[nc] != haystack[hc]) {
 257                                         n = skiptable[(int) haystack[hc]] - i;
 258                                         h += n;
 259                                         count -= n;
 260                                 } else
 261                                         return h;
 262                         }
 263
 264                         return -1;
 265                 }
 266
 267                 // Methods
 268                 [MonoTODO]
 269                 public object Clone ()
 270                 {
 271                         // FIXME: implement me
 272                         return null;
 273                 }
 274
 275                 const int StringCompareModeDirect = 0;
 276                 const int StringCompareModeCaseInsensitive = 1;
 277                 const int StringCompareModeOrdinal = 2;
 278
 279                 internal static int _CompareGetLength (string strA, string strB)
 280                 {
 281                         if ((strA == null) || (strB == null))
 282                                         return 0;
 283                                 else
 284                                 return Math.Max (strA.Length, strB.Length);
 285                 }
 286
 287                 internal static int _CompareChar (char chrA, char chrB, CultureInfo culture,
 288                                                   int mode)
 289                 {
 290                         int result = 0;
 291
 292                         switch (mode) {
 293                         case StringCompareModeDirect:
 294                                 // FIXME: We should do a culture based comparision here,
 295                                 //        but for the moment let's do it by hand.
 296                                 //        In the microsoft runtime, uppercase letters
 297                                 //        sort after lowercase letters in the default
 298                                 //        culture.
 299                                 if (Char.IsUpper (chrA) && Char.IsLower (chrB))
 300                                 return 1;
 301                                 else if (Char.IsLower (chrA) && Char.IsUpper (chrB))
 302                                 return -1;
 303                                 result = (int) (chrA - chrB);
 304                                 break;
 305                         case StringCompareModeCaseInsensitive:
 306                                 result = (int) (Char.ToLower (chrA) - Char.ToLower (chrB));
 307                                 break;
 308                         case StringCompareModeOrdinal:
 309                                 result = (int) (tolowerordinal (chrA) - tolowerordinal (chrB));
 310                                 break;
 311                         }
 312
 313                         if (result == 0)
 314                                         return 0;
 315                         else if (result < 0)
 316                                         return -1;
 317                         else
 318                                 return 1;
 319                 }
 320
 321                 [MonoTODO]
 322                 internal static int _Compare (string strA, int indexA, string strB, int indexB,
 323                                               int length, CultureInfo culture,
 324                                               int mode)
 325
 326                 {
 327                         int i;
 328
 329                         /* When will the hurting stop!?!? */
 330                         if (strA == null) {
 331                                 if (strB == null)
 332                                         return 0;
 333                                 else
 334                                         return -1;
 335                         } else if (strB == null)
 336                                 return 1;
 337
 338                         if (length < 0 || indexA < 0 || indexB < 0)
 339                                 throw new ArgumentOutOfRangeException ();
 340
 341                         if (indexA > strA.Length || indexB > strB.Length)
 342                                 throw new ArgumentOutOfRangeException ();
 343
 344                         // FIXME: Implement culture
 345                         if (culture != null)
 346                                 throw new NotImplementedException ();
 347
 348                         for (i = 0; i < length - 1; i++) {
 349                                 if ((indexA+i >= strA.Length) || (indexB+i >= strB.Length))
 350                                         break;
 351
 352                                 if (_CompareChar (strA[indexA+i], strB[indexB+i], culture, mode) != 0)
 353                                         break;
 354                 }
 355
 356                         if (indexA+i >= strA.Length) {
 357                                 if (indexB+i >= strB.Length)
 358                                         return 0;
 359                                 else
 360                                         return -1;
 361                         } else if (indexB+i >= strB.Length)
 362                                 return 1;
 363
 364                         return _CompareChar (strA[indexA+i], strB[indexB+i], culture, mode);
 365                 }
 366
 367
 368                 public static int Compare (string strA, string strB)
 369                 {
 370                         return Compare (strA, strB, false);
 371                 }
 372
 373                 public static int Compare (string strA, string strB, bool ignoreCase)
 374                 {
 375                         return Compare (strA, strB, ignoreCase, null);
 376                         }
 377
 378                 public static int Compare (string strA, string strB, bool ignoreCase, CultureInfo culture)
 379                 {
 380                         return Compare (strA, 0, strB, 0,
 381                                         _CompareGetLength (strA, strB),
 382                                         ignoreCase, culture);
 383                 }
 384
 385                 public static int Compare (string strA, int indexA, string strB, int indexB, int length)
 386                 {
 387                         return  Compare (strA, indexA, strB, indexB, length, false);
 388                 }
 389
 390                 public static int Compare (string strA, int indexA, string strB, int indexB,
 391                                            int length, bool ignoreCase)
 392                 {
 393                         return Compare (strA, indexA, strB, indexB, length, ignoreCase, null);
 394                 }
 395
 396                 public static int Compare (string strA, int indexA, string strB, int indexB,
 397                                            int length, bool ignoreCase, CultureInfo culture)
 398                 {
 399                         int mode;
 400
 401                         mode = ignoreCase ? StringCompareModeCaseInsensitive :
 402                                 StringCompareModeDirect;
 403
 404                         return _Compare (strA, indexA, strB, indexB, length, culture, mode);
 405                 }
 406
 407                 public static int CompareOrdinal (string strA, string strB)
 408                 {
 409                         return CompareOrdinal (strA, 0, strB, 0, _CompareGetLength (strA, strB));
 410                         }
 411
 412                 public static int CompareOrdinal (string strA, int indexA, string strB, int indexB,
 413                                                   int length)
 414                 {
 415                         return _Compare (strA, indexA, strB, indexB, length, null,
 416                                          StringCompareModeOrdinal);
 417                 }
 418
 419                 public int CompareTo (object obj)
 420                 {
 421                         return Compare (this, obj == null ? null : obj.ToString ());
 422                 }
 423
 424                 public int CompareTo (string str)
 425                 {
 426                         return Compare (this, str);
 427                 }
 428
 429                 public static string Concat (object arg)
 430                 {
 431                         return arg != null ? arg.ToString () : String.Empty;
 432                 }
 433
 434                 public static string Concat (params object[] args)
 435                 {
 436                         string[] strings;
 437                         char[] str;
 438                         int len, i;
 439
 440                         if (args == null)
 441                                 throw new ArgumentNullException ();
 442
 443                         strings = new string [args.Length];
 444                         len = 0;
 445                         i = 0;
 446                         foreach (object arg in args) {
 447                                 /* use Empty for each null argument */
 448                                 if (arg == null)
 449                                         strings[i] = String.Empty;
 450                                 else
 451                                         strings[i] = arg.ToString ();
 452                                 len += strings[i].length;
 453                                 i++;
 454                         }
 455
 456                         if (len == 0)
 457                                 return String.Empty;
 458
 459                         String res = new String (len);
 460                         str = res.c_str;
 461                         i = 0;
 462                         for (int j = 0; j < strings.Length; j++)
 463                                 for (int k = 0; k < strings[j].length; k++)
 464                                         str[i++] = strings[j].c_str[k];
 465
 466                         return res;
 467                 }
 468
 469                 public static string Concat (params string[] values)
 470                 {
 471                         int len, i;
 472                         char[] str;
 473
 474                         if (values == null)
 475                                 throw new ArgumentNullException ();
 476
 477                         len = 0;
 478                         foreach (string value in values)
 479                                 len += value != null ? value.Length : 0;
 480
 481                         if (len == 0)
 482                                 return String.Empty;
 483
 484                         String res = new String (len);
 485                         str = res.c_str;
 486                         i = 0;
 487                         foreach (string value in values) {
 488                                 if (value == null)
 489                                         continue;
 490
 491                                 for (int j = 0; j < value.length; j++)
 492                                         str[i++] = value.c_str[j];
 493                         }
 494
 495                         return res;
 496                 }
 497
 498                 public static string Concat (object arg0, object arg1)
 499                 {
 500                         string str0 = arg0 != null ? arg0.ToString () : String.Empty;
 501                         string str1 = arg1 != null ? arg1.ToString () : String.Empty;
 502
 503                         return Concat (str0, str1);
 504                 }
 505
 506                 public static string Concat (string str0, string str1)
 507                 {
 508                         char[] concat;
 509                         int i, j, len;
 510
 511                         if (str0 == null)
 512                                 str0 = String.Empty;
 513                         if (str1 == null)
 514                                 str1 = String.Empty;
 515
 516                         len = str0.length + str1.length;
 517                         if (len == 0)
 518                                 return String.Empty;
 519
 520                         String res = new String (len);
 521
 522                         concat = res.c_str;
 523                         for (i = 0; i < str0.length; i++)
 524                                 concat[i] = str0.c_str[i];
 525                         for (j = 0 ; j < str1.length; j++)
 526                                 concat[i + j] = str1.c_str[j];
 527
 528                         return res;
 529                 }
 530
 531                 public static string Concat (object arg0, object arg1, object arg2)
 532                 {
 533                         string str0 = arg0 != null ? arg0.ToString () : String.Empty;
 534                         string str1 = arg1 != null ? arg1.ToString () : String.Empty;
 535                         string str2 = arg2 != null ? arg2.ToString () : String.Empty;
 536
 537                         return Concat (str0, str1, str2);
 538                 }
 539
 540                 public static string Concat (string str0, string str1, string str2)
 541                 {
 542                         char[] concat;
 543                         int i, j, k, len;
 544
 545                         if (str0 == null)
 546                                 str0 = String.Empty;
 547                         if (str1 == null)
 548                                 str1 = String.Empty;
 549                         if (str2 == null)
 550                                 str2 = String.Empty;
 551
 552                         len = str0.length + str1.length + str2.length;
 553                         if (len == 0)
 554                                 return String.Empty;
 555
 556                         String res = new String (len);
 557
 558                         concat = res.c_str;
 559                         for (i = 0; i < str0.length; i++)
 560                                 concat[i] = str0.c_str[i];
 561                         for (j = 0; j < str1.length; j++)
 562                                 concat[i + j] = str1.c_str[j];
 563                         for (k = 0; k < str2.length; k++)
 564                                 concat[i + j + k] = str2.c_str[k];
 565
 566                         return res;
 567                 }
 568
 569                 public static string Concat (string str0, string str1, string str2, string str3)
 570                 {
 571                         char[] concat;
 572                         int i, j, k, l, len;
 573
 574                         if (str0 == null)
 575                                 str0 = String.Empty;
 576                         if (str1 == null)
 577                                 str1 = String.Empty;
 578                         if (str2 == null)
 579                                 str2 = String.Empty;
 580                         if (str3 == null)
 581                                 str3 = String.Empty;
 582
 583                         len = str0.length + str1.length + str2.length + str3.length;
 584                         if (len == 0)
 585                                 return String.Empty;
 586                         String res = new String (len);
 587
 588                         concat = res.c_str;
 589                         for (i = 0; i < str0.length; i++)
 590                                 concat[i] = str0.c_str[i];
 591                         for (j = 0; j < str1.length; j++)
 592                                 concat[i + j] = str1.c_str[j];
 593                         for (k = 0; k < str2.length; k++)
 594                                 concat[i + j + k] = str2.c_str[k];
 595                         for (l = 0; l < str3.length; l++)
 596                                 concat[i + j + k + l] = str3.c_str[l];
 597
 598                         return res;
 599                 }
 600
 601                 public static string Copy (string str)
 602                 {
 603                         // FIXME: how do I *copy* a string if I can only have 1 of each?
 604                         if (str == null)
 605                                 throw new ArgumentNullException ();
 606
 607                         return str;
 608                 }
 609
 610                 public void CopyTo (int sourceIndex, char[] destination, int destinationIndex, int count)
 611                 {
 612                         // LAMESPEC: should I null-terminate?
 613                         int i;
 614
 615                         if (destination == null)
 616                                 throw new ArgumentNullException ();
 617
 618                         if (sourceIndex < 0 || destinationIndex < 0 || count < 0)
 619                                 throw new ArgumentOutOfRangeException ();
 620
 621                         if (sourceIndex + count > this.length)
 622                                 throw new ArgumentOutOfRangeException ();
 623
 624                         if (destinationIndex + count > destination.Length)
 625                                 throw new ArgumentOutOfRangeException ();
 626
 627                         for (i = 0; i < count; i++)
 628                                 destination[destinationIndex + i] = this.c_str[sourceIndex + i];
 629                 }
 630
 631                 public bool EndsWith (string value)
 632                 {
 633                         bool endswith = true;
 634                         int start, i;
 635
 636                         if (value == null)
 637                                 throw new ArgumentNullException ();
 638
 639                         start = this.length - value.length;
 640                         if (start < 0)
 641                                 return false;
 642
 643                         for (i = start; i < this.length && endswith; i++)
 644                                 endswith = this.c_str[i] == value.c_str[i - start];
 645
 646                         return endswith;
 647                 }
 648
 649                 public override bool Equals (object obj)
 650                 {
 651                         if (!(obj is String))
 652                                 return false;
 653
 654                         return this == (String) obj;
 655                 }
 656
 657                 public bool Equals (string value)
 658                 {
 659                         return this == value;
 660                 }
 661
 662                 public static bool Equals (string a, string b)
 663                 {
 664                         return a == b;
 665                 }
 666
 667                 public static string Format (string format, object arg0) {
 668                         return Format (null, format, new object[] { arg0 });
 669                 }
 670
 671                 public static string Format (string format, object arg0, object arg1) {
 672                         return Format (null, format, new object[] { arg0, arg1 });
 673                 }
 674
 675                 public static string Format (string format, object arg0, object arg1, object arg2) {
 676                         return Format (null, format, new object[] { arg0, arg1, arg2 });
 677                 }
 678
 679                 public static string Format (string format, params object[] args) {
 680                         return Format (null, format, args);
 681                 }
 682
 683                 public static string Format (IFormatProvider provider, string format, params object[] args) {
 684                         if (format == null || args == null)
 685                                 throw new ArgumentNullException ();
 686
 687                         StringBuilder result = new StringBuilder ();
 688
 689                         int ptr = 0;
 690                         int start = ptr;
 691                         while (ptr < format.Length) {
 692                                 char c = format[ptr ++];
 693
 694                                 if (c == '{') {
 695                                         result.Append (format, start, ptr - start - 1);
 696
 697                                         // check for escaped open bracket
 698
 699                                         if (format[ptr] == '{') {
 700                                                 start = ptr ++;
 701                                                 continue;
 702                                         }
 703
 704                                         // parse specifier
 705
 706                                         int n, width;
 707                                         bool left_align;
 708                                         string arg_format;
 709
 710                                         ParseFormatSpecifier (format, ref ptr, out n, out width, out left_align, out arg_format);
 711                                         if (n >= args.Length)
 712                                                 throw new FormatException ("Index (zero based) must be greater than or equal to zero and less than the size of the argument list.");
 713
 714                                         // format argument
 715
 716                                         object arg = args[n];
 717
 718                                         string str;
 719                                         if (arg == null)
 720                                                 str = "";
 721                                         else if (arg is IFormattable)
 722                                                 str = ((IFormattable)arg).ToString (arg_format, provider);
 723                                         else
 724                                                 str = arg.ToString ();
 725
 726                                         // pad formatted string and append to result
 727
 728                                         if (width > str.Length) {
 729                                                 string pad = new String (' ', width - str.Length);
 730
 731                                                 if (left_align) {
 732                                                         result.Append (str);
 733                                                         result.Append (pad);
 734                                                 }
 735                                                 else {
 736                                                         result.Append (pad);
 737                                                         result.Append (str);
 738                                                 }
 739                                         }
 740                                         else
 741                                                 result.Append (str);
 742
 743                                         start = ptr;
 744                                 }
 745                                 else if (c == '}' && format[ptr] == '}') {
 746                                         result.Append (format, start, ptr - start - 1);
 747                                         start = ptr ++;
 748                                 }
 749                         }
 750
 751                         if (start < format.Length)
 752                                 result.Append (format.Substring (start));
 753
 754                         return result.ToString ();
 755                 }
 756
 757                 public CharEnumerator GetEnumerator ()
 758                 {
 759                         return new CharEnumerator (this);
 760                 }
 761
 762                 IEnumerator IEnumerable.GetEnumerator ()
 763                 {
 764                         return new CharEnumerator (this);
 765                 }
 766
 767                 public override int GetHashCode ()
 768                 {
 769                         int h = 0;
 770                         int i;
 771                         for (i = 0; i < length; ++i)
 772                                 h = (h << 5) - h + c_str [i];
 773                         return h;
 774                 }
 775
 776                 public TypeCode GetTypeCode ()
 777                 {
 778                         return TypeCode.String;
 779                 }
 780
 781                 public int IndexOf (char value)
 782                 {
 783                         return IndexOf (value, 0, this.length);
 784                 }
 785
 786                 public int IndexOf (string value)
 787                 {
 788                         return IndexOf (value, 0, this.length);
 789                 }
 790
 791                 public int IndexOf (char value, int startIndex)
 792                 {
 793                         return IndexOf (value, startIndex, this.length - startIndex);
 794                 }
 795
 796                 public int IndexOf (string value, int startIndex)
 797                 {
 798                         return IndexOf (value, startIndex, this.length - startIndex);
 799                 }
 800
 801                 public int IndexOf (char value, int startIndex, int count)
 802                 {
 803                         int i;
 804
 805                         if (startIndex < 0 || count < 0 || startIndex + count > this.length)
 806                                 throw new ArgumentOutOfRangeException ();
 807
 808                         for (i = startIndex; i - startIndex < count; i++)
 809                                 if (this.c_str[i] == value)
 810                                         return i;
 811
 812                         return -1;
 813                 }
 814
 815                 public int IndexOf (string value, int startIndex, int count)
 816                 {
 817                         if (value == null)
 818                                 throw new ArgumentNullException ();
 819
 820                         if (startIndex < 0 || count < 0 || startIndex + count > this.length)
 821                                 throw new ArgumentOutOfRangeException ();
 822
 823 #if XXX
 824                         return BoyerMoore (this.c_str, value, startIndex, count);
 825 #endif
 826                         int i;
 827                         for (i = startIndex; i - startIndex + value.length <= count; ) {
 828                                 if (this.c_str[i] == value.c_str [0]) {
 829                                         bool equal = true;
 830                                         int j, nexti = 0;
 831
 832                                         for (j = 1; equal && j < value.length; j++) {
 833                                                 equal = this.c_str[i + j] == value.c_str [j];
 834                                                 if (this.c_str [i + j] == value.c_str [0] && nexti == 0)
 835                                                         nexti = i + j;
 836                                         }
 837
 838                                         if (equal)
 839                                                 return i;
 840
 841                                         if (nexti != 0)
 842                                                 i = nexti;
 843                                         else
 844                                                 i += j;
 845                                 } else
 846                                         i++;
 847                         }
 848
 849                         return -1;
 850                 }
 851
 852                 public int IndexOfAny (char[] values)
 853                 {
 854                         return IndexOfAny (values, 0, this.length);
 855                 }
 856
 857                 public int IndexOfAny (char[] values, int startIndex)
 858                 {
 859                         return IndexOfAny (values, startIndex, this.length - startIndex);
 860                 }
 861
 862                 public int IndexOfAny (char[] values, int startIndex, int count)
 863                 {
 864                         if (values == null)
 865                                 throw new ArgumentNullException ();
 866
 867                         if (startIndex < 0 || count < 0 || startIndex + count > this.length)
 868                                 throw new ArgumentOutOfRangeException ();
 869
 870                         for (int i = startIndex; i < startIndex + count; i++) {
 871                                 for (int j = 0; j < strlen (values); j++) {
 872                                         if (this.c_str[i] == values[j])
 873                                                 return i;
 874                                 }
 875                         }
 876
 877                         return -1;
 878                 }
 879
 880                 public string Insert (int startIndex, string value)
 881                 {
 882                         char[] str;
 883                         int i, j;
 884
 885                         if (value == null)
 886                                 throw new ArgumentNullException ();
 887
 888                         if (startIndex < 0 || startIndex > this.length)
 889                                 throw new ArgumentOutOfRangeException ();
 890
 891                         String res = new String (value.length + this.length);
 892
 893                         str = res.c_str;
 894                         for (i = 0; i < startIndex; i++)
 895                                 str[i] = this.c_str[i];
 896                         for (j = 0; j < value.length; j++)
 897                                 str[i + j] = value.c_str[j];
 898                         for ( ; i < this.length; i++)
 899                                 str[i + j] = this.c_str[i];
 900
 901                         return res;
 902                 }
 903
 904                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
 905                 internal extern static string _Intern (string str);
 906
 907                 public static string Intern (string str)
 908                 {
 909                         if (str == null)
 910                                 throw new ArgumentNullException ();
 911
 912                         return _Intern (str);
 913                 }
 914
 915                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
 916                 internal extern static string _IsInterned (string str);
 917
 918                 public static string IsInterned (string str)
 919                 {
 920                         if (str == null)
 921                                 throw new ArgumentNullException ();
 922
 923                         return _IsInterned (str);
 924                 }
 925
 926                 public static string Join (string separator, string[] value)
 927                 {
 928                         if (value == null)
 929                                 throw new ArgumentNullException ();
 930
 931                         return Join (separator, value, 0, value.Length);
 932                 }
 933
 934                 public static string Join (string separator, string[] value, int startIndex, int count)
 935                 {
 936                         // LAMESPEC: msdn doesn't specify what happens when separator is null
 937                         int len, i, j, used;
 938                         char[] str;
 939
 940                         if (separator == null || value == null)
 941                                 throw new ArgumentNullException ();
 942
 943                         if (startIndex + count > value.Length)
 944                                 throw new ArgumentOutOfRangeException ();
 945
 946                         len = 0;
 947                         for (i = startIndex, used = 0; used < count; i++, used++) {
 948                                 if (i != startIndex)
 949                                         len += separator.length;
 950
 951                                 len += value[i].length;
 952                         }
 953
 954                         // We have no elements to join?
 955                         if (i == startIndex)
 956                                 return String.Empty;
 957
 958                         String res = new String (len);
 959
 960                         str = res.c_str;
 961                         for (i = 0; i < value[startIndex].length; i++)
 962                                 str[i] = value[startIndex][i];
 963
 964                         used = 1;
 965                         for (j = startIndex + 1; used < count; j++, used++) {
 966                                 int k;
 967
 968                                 for (k = 0; k < separator.length; k++)
 969                                         str[i++] = separator.c_str[k];
 970                                 for (k = 0; k < value[j].length; k++)
 971                                         str[i++] = value[j].c_str[k];
 972                         }
 973
 974                         return res;
 975                 }
 976
 977                 public int LastIndexOf (char value)
 978                 {
 979                         int i = this.length;
 980                         if (i == 0)
 981                                 return -1;
 982                         --i;
 983                         for (; i >= 0; i--) {
 984                                 if (this.c_str[i] == value)
 985                                         return i;
 986                         }
 987
 988                         return -1;
 989                 }
 990
 991                 public int LastIndexOf (string value)
 992                 {
 993                         if (value == null)
 994                                 throw new ArgumentNullException ();
 995                         if (value.length == 0)
 996                                 return 0;
 997                         if (this.length == 0)
 998                                 return -1;
 999
1000                         return LastIndexOf (value, this.length - 1, this.length);
1001                 }
1002
1003                 public int LastIndexOf (char value, int startIndex)
1004                 {
1005                         if (startIndex < 0 || startIndex >= this.length)
1006                                 throw new ArgumentOutOfRangeException ();
1007
1008                         for (int i = startIndex; i >= 0; i--) {
1009                                 if (this.c_str[i] == value)
1010                                         return i;
1011                         }
1012
1013                         return -1;
1014                 }
1015
1016                 public int LastIndexOf (string value, int startIndex)
1017                 {
1018                         return LastIndexOf (value, startIndex, startIndex + 1);
1019                 }
1020
1021                 public int LastIndexOf (char value, int startIndex, int count)
1022                 {
1023                         if (startIndex < 0 || count < 0)
1024                                 throw new ArgumentOutOfRangeException ();
1025
1026                         if (startIndex >= this.length || startIndex - count + 1 < 0)
1027                                 throw new ArgumentOutOfRangeException ();
1028
1029                         for (int i = startIndex; i > startIndex - count; i--) {
1030                                 if (this.c_str[i] == value)
1031                                         return i;
1032                         }
1033
1034                         return -1;
1035                 }
1036
1037                 public int LastIndexOf (string value, int startIndex, int count)
1038                 {
1039                         // startIndex points to the end of value, ie. we're searching backwards.
1040                         int i, len;
1041
1042                         if (value == null)
1043                                 throw new ArgumentNullException ();
1044
1045                         if (startIndex < 0 || startIndex > this.length)
1046                                 throw new ArgumentOutOfRangeException ();
1047
1048                         if (count < 0 || startIndex - count + 1 < 0)
1049                                 throw new ArgumentOutOfRangeException ();
1050
1051                         if (value.length > startIndex)
1052                                 return -1;
1053
1054                         if (value == String.Empty)
1055                                 return startIndex;
1056
1057                         if (startIndex == this.length)
1058                                 startIndex--;
1059
1060                         // FIXME: use a reversed-unicode-safe-Boyer-Moore?
1061                         len = value.length - 1;
1062                         for (i = startIndex; i > startIndex - count; i--) {
1063
1064                                 if (this.c_str[i] == value.c_str[len]) {
1065                                         bool equal = true;
1066                                         int j;
1067
1068                                         for (j = 0; equal && j < len; j++)
1069                                                 equal = this.c_str[i - j] == value.c_str[len - j];
1070
1071                                         if (equal)
1072                                                 return i - j;
1073                                 }
1074                         }
1075
1076                         return -1;
1077                 }
1078
1079                 public int LastIndexOfAny (char[] values)
1080                 {
1081                         return LastIndexOfAny (values, this.length - 1, this.length);
1082                 }
1083
1084                 public int LastIndexOfAny (char[] values, int startIndex)
1085                 {
1086                         return LastIndexOfAny (values, startIndex, startIndex + 1);
1087                 }
1088
1089                 public int LastIndexOfAny (char[] values, int startIndex, int count)
1090                 {
1091                         int i;
1092
1093                         if (values == null)
1094                                 throw new ArgumentNullException ();
1095
1096                         if (startIndex < 0 || count < 0 || startIndex - count + 1 < 0)
1097                                 throw new ArgumentOutOfRangeException ();
1098
1099                         for (i = startIndex; i > startIndex - count; i--) {
1100                                 for (int j = 0; j < strlen (values); j++) {
1101                                         if (this.c_str[i] == values[j])
1102                                                 return i;
1103                                 }
1104                         }
1105
1106                         return -1;
1107                 }
1108
1109                 public string PadLeft (int totalWidth)
1110                 {
1111                         return PadLeft (totalWidth, ' ');
1112                 }
1113
1114                 public string PadLeft (int totalWidth, char padChar)
1115                 {
1116                         char[] str;
1117                         int i, j;
1118
1119                         if (totalWidth < 0)
1120                                 throw new ArgumentException ();
1121
1122                         str = new char [totalWidth > this.length ? totalWidth : this.length];
1123                         for (i = 0; i < totalWidth - this.length; i++)
1124                                 str[i] = padChar;
1125
1126                         for (j = 0; j < this.length; i++, j++)
1127                                 str[i] = this.c_str[j];
1128
1129                         return new String (str);
1130                 }
1131
1132                 public string PadRight (int totalWidth)
1133                 {
1134                         return PadRight (totalWidth, ' ');
1135                 }
1136
1137                 public string PadRight (int totalWidth, char padChar)
1138                 {
1139                         char[] str;
1140                         int i;
1141
1142                         if (totalWidth < 0)
1143                                 throw new ArgumentException ();
1144
1145                         str = new char [totalWidth > this.length ? totalWidth : this.length];
1146                         for (i = 0; i < this.length; i++)
1147                                 str[i] = this.c_str[i];
1148
1149                         for ( ; i < str.Length; i++)
1150                                 str[i] = padChar;
1151
1152                         return new String (str);
1153                 }
1154
1155                 public string Remove (int startIndex, int count)
1156                 {
1157                         char[] str;
1158                         int i, j, len;
1159
1160                         if (startIndex < 0 || count < 0 || startIndex + count > this.length)
1161                                 throw new ArgumentOutOfRangeException ();
1162
1163                         len = this.length - count;
1164                         if (len == 0)
1165                                 return String.Empty;
1166
1167                         String res = new String (len);
1168                         str = res.c_str;
1169                         for (i = 0; i < startIndex; i++)
1170                                 str[i] = this.c_str[i];
1171                         for (j = i + count; j < this.length; j++)
1172                                 str[i++] = this.c_str[j];
1173
1174                         return res;
1175                 }
1176
1177                 public string Replace (char oldChar, char newChar)
1178                 {
1179                         char[] str;
1180                         int i;
1181
1182                         String res = new String (length);
1183                         str = res.c_str;
1184                         for (i = 0; i < this.length; i++) {
1185                                 if (this.c_str[i] == oldChar)
1186                                         str[i] = newChar;
1187                                 else
1188                                         str[i] = this.c_str[i];
1189                         }
1190
1191                         return res;
1192                 }
1193
1194                 public string Replace (string oldValue, string newValue)
1195                 {
1196                         // If newValue is null, oldValue is removed.
1197                         int index, len, i, j, newlen;
1198                         string thestring;
1199                         char[] str;
1200
1201                         if (oldValue == null)
1202                                 throw new ArgumentNullException ();
1203
1204                         thestring = Substring (0, this.length);
1205                         index = 0;
1206
1207                         // Runs until all occurences of oldValue have been replaced.
1208                         while (true) {
1209                                 // Use IndexOf in case I later rewrite it to use Boyer-Moore
1210                                 index = thestring.IndexOf (oldValue, index);
1211
1212                                 if (index == -1)
1213                                         return thestring;
1214
1215                                 newlen = (newValue == null) ? 0 : newValue.length;
1216                                 len = thestring.length - oldValue.length + newlen;
1217
1218                                 if (len == 0)
1219                                         return String.Empty;
1220
1221                                 String res = new String (len);
1222                                 str = res.c_str;
1223                                 for (i = 0; i < index; i++)
1224                                         str[i] = thestring.c_str[i];
1225                                 for (j = 0; j < newlen; j++)
1226                                         str[i++] = newValue[j];
1227                                 for (j = index + oldValue.length; j < thestring.length; j++)
1228                                         str[i++] = thestring.c_str[j];
1229
1230                                 // Increment index, we're already done replacing until this index.
1231                                 thestring = res;
1232                                 index += newlen;
1233                         }
1234                 }
1235
1236                 private int splitme (char[] separators, int startIndex)
1237                 {
1238                         /* this is basically a customized IndexOfAny() for the Split() methods */
1239                         for (int i = startIndex; i < this.length; i++) {
1240                                 if (separators != null) {
1241                                         foreach (char sep in separators) {
1242                                                 if (this.c_str[i] == sep)
1243                                                         return i - startIndex;
1244                                         }
1245                                 } else if (is_lwsp (this.c_str[i])) {
1246                                         return i - startIndex;
1247                                 }
1248                         }
1249
1250                         return -1;
1251                 }
1252
1253                 public string[] Split (params char[] separator)
1254                 {
1255                         /**
1256                          * split:
1257                          * @separator: delimiting chars or null to split on whtspc
1258                          *
1259                          * Returns: 1. An array consisting of a single
1260                          * element (@this) if none of the delimiting
1261                          * chars appear in @this. 2. An array of
1262                          * substrings which are delimited by one of
1263                          * the separator chars. 3. An array of
1264                          * substrings separated by whitespace if
1265                          * @separator is null. The Empty string should
1266                          * be returned wherever 2 delimiting chars are
1267                          * adjacent.
1268                          **/
1269                         // FIXME: would using a Queue be better?
1270                         string[] strings;
1271                         ArrayList list;
1272                         int index, len;
1273
1274                         list = new ArrayList ();
1275                         for (index = 0, len = 0; index < this.length; index += len + 1) {
1276                                 len = splitme (separator, index);
1277                                 len = len > -1 ? len : this.length - index;
1278                                 if (len == 0) {
1279                                         list.Add (String.Empty);
1280                                 } else {
1281                                         char[] str;
1282                                         int i;
1283
1284                                         str = new char [len];
1285                                         for (i = 0; i < len; i++)
1286                                                 str[i] = this.c_str[index + i];
1287
1288                                         list.Add (new String (str));
1289                                 }
1290                         }
1291
1292                         strings = new string [list.Count];
1293                         if (list.Count == 1) {
1294                                 /* special case for an array holding @this */
1295                                 strings[0] = this;
1296                         } else {
1297                                 for (index = 0; index < list.Count; index++)
1298                                         strings[index] = (string) list[index];
1299                         }
1300
1301                         return strings;
1302                 }
1303
1304                 public string[] Split (char[] separator, int maxCount)
1305                 {
1306                         // FIXME: would using Queue be better than ArrayList?
1307                         string[] strings;
1308                         ArrayList list;
1309                         int index, len, used;
1310
1311                         if (maxCount == 0)
1312                                 return new string[0];
1313                         else if (maxCount < 0)
1314                                 throw new ArgumentOutOfRangeException ();
1315
1316                         used = 0;
1317                         list = new ArrayList ();
1318                         for (index = 0, len = 0; index < this.length && used < maxCount; index += len + 1) {
1319                                 len = splitme (separator, index);
1320                                 len = len > -1 ? len : this.length - index;
1321                                 if (len == 0) {
1322                                         list.Add (String.Empty);
1323                                 } else {
1324                                         char[] str;
1325                                         int i;
1326
1327                                         str = new char [len];
1328                                         for (i = 0; i < len; i++)
1329                                                 str[i] = this.c_str[index + i];
1330
1331                                         list.Add (new String (str));
1332                                 }
1333                                 used++;
1334                         }
1335
1336                         /* fit the remaining chunk of the @this into it's own element */
1337                         if (index <= this.length)
1338                         {
1339                                 char[] str;
1340                                 int i;
1341
1342                                 str = new char [this.length - index];
1343                                 for (i = index; i < this.length; i++)
1344                                         str[i - index] = this.c_str[i];
1345
1346                                 // maxCount cannot be zero if we reach this point and this means that
1347                                 // index can't be zero either.
1348                                 if (used == maxCount)
1349                                         list[used-1] += this.c_str[index-1] + new String (str);
1350                                 else
1351                                 list.Add (new String (str));
1352                         }
1353
1354                         strings = new string [list.Count];
1355                         if (list.Count == 1) {
1356                                 /* special case for an array holding @this */
1357                                 strings[0] = this;
1358                         } else {
1359                                 for (index = 0; index < list.Count; index++)
1360                                         strings[index] = (string) list[index];
1361                         }
1362
1363                         return strings;
1364                 }
1365
1366                 public bool StartsWith (string value)
1367                 {
1368                         bool startswith = true;
1369                         int i;
1370
1371                         if (value == null)
1372                                 throw new ArgumentNullException ();
1373
1374                         if (value.length > this.length)
1375                                 return false;
1376
1377                         for (i = 0; i < value.length && startswith; i++)
1378                                 startswith = startswith && value.c_str[i] == this.c_str[i];
1379
1380                         return startswith;
1381                 }
1382
1383                 public string Substring (int startIndex)
1384                 {
1385                         char[] str;
1386                         int i, len;
1387
1388                         if (startIndex < 0 || startIndex > this.length)
1389                                 throw new ArgumentOutOfRangeException ();
1390
1391                         len = this.length - startIndex;
1392                         if (len == 0)
1393                                 return String.Empty;
1394                         String res = new String (len);
1395                         str = res.c_str;
1396                         for (i = startIndex; i < this.length; i++)
1397                                 str[i - startIndex] = this.c_str[i];
1398
1399                         return res;
1400                 }
1401
1402                 public string Substring (int startIndex, int length)
1403                 {
1404                         char[] str;
1405                         int i;
1406
1407                         if (startIndex < 0 || length < 0 || startIndex + length > this.length)
1408                                 throw new ArgumentOutOfRangeException ();
1409
1410                         if (length == 0)
1411                                 return String.Empty;
1412
1413                         String res = new String (length);
1414                         str = res.c_str;
1415                         for (i = startIndex; i < startIndex + length; i++)
1416                                 str[i - startIndex] = this.c_str[i];
1417
1418                         return res;
1419                 }
1420
1421                 bool IConvertible.ToBoolean (IFormatProvider provider)
1422                 {
1423                         return Convert.ToBoolean (this);
1424                 }
1425
1426                 byte IConvertible.ToByte (IFormatProvider provider)
1427                 {
1428                         return Convert.ToByte (this);
1429                 }
1430
1431                 char IConvertible.ToChar (IFormatProvider provider)
1432                 {
1433                         return Convert.ToChar (this);
1434                 }
1435
1436                 public char[] ToCharArray ()
1437                 {
1438                         return ToCharArray (0, this.length);
1439                 }
1440
1441                 public char[] ToCharArray (int startIndex, int length)
1442                 {
1443                         char[] chars;
1444                         int i;
1445
1446                         if (startIndex < 0 || length < 0 || startIndex + length > this.length)
1447                                 throw new ArgumentOutOfRangeException ();
1448
1449                         chars = new char [length];
1450                         for (i = startIndex; i < length; i++)
1451                                 chars[i - startIndex] = this.c_str[i];
1452
1453                         return chars;
1454                 }
1455
1456                 DateTime IConvertible.ToDateTime (IFormatProvider provider)
1457                 {
1458                         return Convert.ToDateTime (this);
1459                 }
1460
1461                 decimal IConvertible.ToDecimal (IFormatProvider provider)
1462                 {
1463                         return Convert.ToDecimal (this);
1464                 }
1465
1466                 double IConvertible.ToDouble (IFormatProvider provider)
1467                 {
1468                         return Convert.ToDouble (this);
1469                 }
1470
1471                 short IConvertible.ToInt16 (IFormatProvider provider)
1472                 {
1473                         return Convert.ToInt16 (this);
1474                 }
1475
1476                 int IConvertible.ToInt32 (IFormatProvider provider)
1477                 {
1478                         return Convert.ToInt32 (this);
1479                 }
1480
1481                 long IConvertible.ToInt64 (IFormatProvider provider)
1482                 {
1483                         return Convert.ToInt64 (this);
1484                 }
1485
1486                 public string ToLower ()
1487                 {
1488                         char[] str;
1489                         int i;
1490
1491                         String res = new String (length);
1492                         str = res.c_str;
1493                         for (i = 0; i < this.length; i++)
1494                                 str[i] = Char.ToLower (this.c_str[i]);
1495
1496                         return res;
1497                 }
1498
1499                 [MonoTODO]
1500                 public string ToLower (CultureInfo culture)
1501                 {
1502                         // FIXME: implement me
1503                         throw new NotImplementedException ();
1504
1505                 }
1506
1507                 [CLSCompliant(false)]
1508                 sbyte IConvertible.ToSByte (IFormatProvider provider)
1509                 {
1510                         return Convert.ToSByte (this);
1511                 }
1512
1513                 float IConvertible.ToSingle (IFormatProvider provider)
1514                 {
1515                         return Convert.ToSingle (this);
1516                 }
1517
1518                 public override string ToString ()
1519                 {
1520                         return this;
1521                 }
1522
1523                 string IConvertible.ToString (IFormatProvider format)
1524                 {
1525                         return this;
1526                 }
1527
1528                 object IConvertible.ToType (Type conversionType, IFormatProvider provider)
1529                 {
1530                         return Convert.ToType (this, conversionType,  provider);
1531                 }
1532
1533                 [CLSCompliant(false)]
1534                 ushort IConvertible.ToUInt16 (IFormatProvider provider)
1535                 {
1536                         return Convert.ToUInt16 (this);
1537                 }
1538
1539                 [CLSCompliant(false)]
1540                 uint IConvertible.ToUInt32 (IFormatProvider provider)
1541                 {
1542                         return Convert.ToUInt32 (this);
1543                 }
1544
1545                 [CLSCompliant(false)]
1546                 ulong IConvertible.ToUInt64 (IFormatProvider provider)
1547                 {
1548                         return Convert.ToUInt64 (this);
1549                 }
1550
1551                 public string ToUpper ()
1552                 {
1553                         char[] str;
1554                         int i;
1555
1556                         String res = new String (length);
1557                         str = res.c_str;
1558                         for (i = 0; i < this.length; i++)
1559                                 str[i] = Char.ToUpper (this.c_str[i]);
1560
1561                         return res;
1562                 }
1563
1564                 [MonoTODO]
1565                 public string ToUpper (CultureInfo culture)
1566                 {
1567                         // FIXME: implement me
1568                         throw new NotImplementedException ();
1569                 }
1570
1571                 public string Trim ()
1572                 {
1573                         return Trim (null);
1574                 }
1575
1576                 public string Trim (params char[] trimChars)
1577                 {
1578                         int begin, end;
1579                         bool matches = false;
1580
1581                         for (begin = 0; begin < this.length; begin++) {
1582                                 if (trimChars != null) {
1583                                         matches = false;
1584                                         foreach (char c in trimChars) {
1585                                                 matches = this.c_str[begin] == c;
1586                                                 if (matches)
1587                                                         break;
1588                                         }
1589                                         if (matches)
1590                                                 continue;
1591                                 } else {
1592                                         matches = is_lwsp (this.c_str[begin]);
1593                                         if (matches)
1594                                                 continue;
1595                                 }
1596                                 break;
1597                         }
1598
1599                         for (end = this.length - 1; end > begin; end--) {
1600                                 if (trimChars != null) {
1601                                         matches = false;
1602                                         foreach (char c in trimChars) {
1603                                                 matches = this.c_str[end] == c;
1604                                                 if (matches)
1605                                                         break;
1606                                         }
1607                                         if (matches)
1608                                                 continue;
1609                                 } else {
1610                                         matches = is_lwsp (this.c_str[end]);
1611                                         if (matches)
1612                                                 continue;
1613                                 }
1614                                 break;
1615                         }
1616                         end++;
1617
1618                         if (begin >= end)
1619                                 return String.Empty;
1620
1621                         return Substring (begin, end - begin);
1622                 }
1623
1624                 public string TrimEnd (params char[] trimChars)
1625                 {
1626                         bool matches = true;
1627                         int end;
1628
1629                         for (end = this.length - 1; matches && end > 0; end--) {
1630
1631                                 if (trimChars != null) {
1632                                         matches = false;
1633                                         foreach (char c in trimChars) {
1634                                                 matches = this.c_str[end] == c;
1635                                                 if (matches)
1636                                                         break;
1637                                         }
1638                                 } else {
1639                                         matches = is_lwsp (this.c_str[end]);
1640                                 }
1641
1642                                 if (!matches)
1643                                         return Substring (0, end+1);
1644                         }
1645
1646                         if (end == 0)
1647                                 return String.Empty;
1648
1649                         return Substring (0, end);
1650                 }
1651
1652                 public string TrimStart (params char[] trimChars)
1653                 {
1654                         bool matches = true;
1655                         int begin;
1656
1657                         for (begin = 0; matches && begin < this.length; begin++) {
1658                                 if (trimChars != null) {
1659                                         matches = false;
1660                                         foreach (char c in trimChars) {
1661                                                 matches = this.c_str[begin] == c;
1662                                                 if (matches)
1663                                                         break;
1664                                         }
1665                                 } else {
1666                                         matches = is_lwsp (this.c_str[begin]);
1667                                 }
1668
1669                                 if (!matches)
1670                                         return Substring (begin, this.length - begin);
1671                         }
1672
1673                                 return String.Empty;
1674                 }
1675
1676                 // Operators
1677                 public static bool operator ==(string a, string b)
1678                 {
1679                         if ((object)a == null) {
1680                                 if ((object)b == null)
1681                                         return true;
1682                                 return false;
1683                         }
1684                         if ((object)b == null)
1685                                 return false;
1686
1687                         if (a.length != b.length)
1688                                 return false;
1689
1690                         int l = a.length;
1691                         for (int i = 0; i < l; i++)
1692                                 if (a.c_str[i] != b.c_str[i])
1693                                         return false;
1694
1695                         return true;
1696                 }
1697
1698                 public static bool operator !=(string a, string b)
1699                 {
1700                         return !(a == b);
1701                 }
1702
1703                 // private
1704
1705                 private static void ParseFormatSpecifier (string str, ref int ptr, out int n, out int width, out bool left_align, out string format) {
1706                         // parses format specifier of form:
1707                         //   N,[[-]M][:F]}
1708                         //
1709                         // where:
1710
1711                         try {
1712                                 // N = argument number (non-negative integer)
1713
1714                                 n = ParseDecimal (str, ref ptr);
1715                                 if (n < 0)
1716                                         throw new FormatException ("Input string was not in correct format.");
1717
1718                                 // M = width (non-negative integer)
1719
1720                                 if (str[ptr] == ',') {
1721                                         left_align = (str[++ ptr] == '-');
1722                                         if (left_align)
1723                                                 ++ ptr;
1724
1725                                         width = ParseDecimal (str, ref ptr);
1726                                         if (width < 0)
1727                                                 throw new FormatException ("Input string was not in correct format.");
1728                                 }
1729                                 else {
1730                                         width = 0;
1731                                         left_align = false;
1732                                 }
1733
1734                                 // F = argument format (string)
1735
1736                                 if (str[ptr] == ':') {
1737                                         int start = ++ ptr;
1738                                         while (str[ptr] != '}')
1739                                                 ++ ptr;
1740
1741                                         format = str.Substring (start, ptr - start);
1742                                 }
1743                                 else
1744                                         format = null;
1745
1746                                 if (str[ptr ++] != '}')
1747                                         throw new FormatException ("Input string was not in correct format.");
1748                         }
1749                         catch (IndexOutOfRangeException) {
1750                                 throw new FormatException ("Input string was not in correct format.");
1751                         }
1752                 }
1753
1754                 private static int ParseDecimal (string str, ref int ptr) {
1755                         int p = ptr;
1756                         int n = 0;
1757                         while (true) {
1758                                 char c = str[p];
1759                                 if (c < '0' || '9' < c)
1760                                         break;
1761
1762                                 n = n * 10 + c - '0';
1763                                 ++ p;
1764                         }
1765
1766                         if (p == ptr)
1767                                 return -1;
1768
1769                         ptr = p;
1770                         return n;
1771                 }
1772         }
1773 }