mcs/class/corlib/System/String.cs

   1 //
   2 // System.String.cs
   3 //
   4 // Authors:
   5 //        Patrik Torstensson (patrik.torstensson@labs2.com)
   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 using System;
  13 using System.Text;
  14 using System.Collections;
  15 using System.Globalization;
  16 using System.Runtime.CompilerServices;
  17
  18 namespace System {
  19         [Serializable]
  20         public sealed class String : IConvertible, IComparable, ICloneable, IEnumerable {
  21                 private int length;
  22
  23                 public static readonly String Empty = "";
  24
  25                 [CLSCompliant(false), MethodImplAttribute(MethodImplOptions.InternalCall)]
  26                 unsafe public extern String(char *value);
  27
  28                 [CLSCompliant(false), MethodImplAttribute(MethodImplOptions.InternalCall)]
  29                 unsafe public extern String(char *value, int sindex, int length);
  30
  31                 [CLSCompliant(false), MethodImplAttribute(MethodImplOptions.InternalCall)]
  32                 unsafe public extern String(sbyte *value);
  33
  34                 [CLSCompliant(false), MethodImplAttribute(MethodImplOptions.InternalCall)]
  35                 unsafe public extern String(sbyte *value, int sindex, int length);
  36
  37                 [CLSCompliant(false), MethodImplAttribute(MethodImplOptions.InternalCall)]
  38                 unsafe public extern String(sbyte *value, int sindex, int length, Encoding enc);
  39
  40                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
  41                 public extern String(char [] val, int sindex, int length);
  42
  43                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
  44                 public extern String(char [] val);
  45
  46                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
  47                 public extern String(char c, int count);
  48
  49                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
  50                 public extern override int GetHashCode();
  51
  52                 public static bool Equals(String str1, String str2) {
  53                         if ((Object) str1 == (Object) str2)
  54                                 return true;
  55
  56                         if (null == (Object) str1 || null == (Object) str2)
  57                                 return false;
  58
  59                         if (str1.length != str2.length)
  60                                 return false;
  61
  62                         return InternalEquals(str1, str2);
  63                 }
  64
  65                 public static bool operator == (String str1, String str2) {
  66                         return Equals(str1, str2);
  67                 }
  68
  69                 public static bool operator != (String str1, String str2) {
  70                         return !Equals(str1, str2);
  71                 }
  72
  73                 public override bool Equals(Object obj) {
  74                         if (null == obj)
  75                                 return false;
  76
  77                         if (!(obj is String))
  78                                 return false;
  79
  80                         return InternalEquals(this, (String) obj);
  81                 }
  82
  83                 public bool Equals(String value) {
  84                         if (null == value)
  85                                 return false;
  86
  87                         if (length != value.length)
  88                                 return false;
  89
  90                         return InternalEquals(this, value);
  91                 }
  92
  93                 [IndexerName("Chars")]
  94                 public extern char this[int index] {
  95                         [MethodImplAttribute(MethodImplOptions.InternalCall)]
  96                         get;
  97                 }
  98
  99                 public Object Clone() {
 100                         return this;
 101                 }
 102
 103                 public TypeCode GetTypeCode () {
 104                         return TypeCode.String;
 105                 }
 106
 107                 public void CopyTo(int sindex, char[] dest, int dindex, int count) {
 108                         // LAMESPEC: should I null-terminate?
 109
 110                         if (dest == null)
 111                                 throw new ArgumentNullException();
 112
 113                         if (sindex < 0 || dindex < 0 || count < 0)
 114                                 throw new ArgumentOutOfRangeException ();
 115
 116                         if (sindex + count > Length)
 117                                 throw new ArgumentOutOfRangeException ();
 118
 119                         if (dindex + count > dest.Length)
 120                                 throw new ArgumentOutOfRangeException ();
 121
 122                         InternalCopyTo(sindex, dest, dindex, count);
 123                 }
 124
 125                 public char[] ToCharArray() {
 126                         return ToCharArray(0, length);
 127                 }
 128
 129                 public char[] ToCharArray(int sindex, int length) {
 130                         if (sindex < 0 || length < 0 || sindex + length > this.length)
 131                                 throw new ArgumentOutOfRangeException ();
 132
 133                         char [] tmp = new char[length];
 134
 135                         InternalCopyTo(sindex, tmp, 0, length);
 136
 137                         return tmp;
 138                 }
 139
 140                 public String [] Split(params char [] separator) {
 141                         return Split(separator, Int32.MaxValue);
 142                 }
 143
 144                 public String[] Split(char[] separator, int count) {
 145                         if (null == separator) {
 146                                 separator = WhiteChars;
 147                         }
 148
 149                         if (count < 0)
 150                                 throw new ArgumentOutOfRangeException ();
 151
 152                         if (count == 0)
 153                                 return new String[0];
 154
 155                         if (count == 1)
 156                                 return new String[1] { ToString() };
 157
 158                         return InternalSplit(separator, count);
 159                 }
 160
 161                 public String Substring (int sindex) {
 162                         if (sindex < 0 || sindex > this.length) {
 163                                 throw new ArgumentOutOfRangeException();
 164                         }
 165
 166                         string tmp = InternalAllocateStr(this.length - sindex);
 167                         InternalStrcpy(tmp, 0, this, sindex, length - sindex);
 168
 169                         return tmp;
 170                 }
 171
 172                 public String Substring (int sindex, int length) {
 173                         if (length < 0 || sindex < 0 || sindex + length > this.length) {
 174                                 throw new ArgumentOutOfRangeException();
 175                         }
 176
 177                         if (length == 0)
 178                                 return String.Empty;
 179
 180                         string tmp = InternalAllocateStr(length);
 181                         InternalStrcpy(tmp, 0, this, sindex, length);
 182
 183                         return tmp;
 184                 }
 185
 186                 private static readonly char[] WhiteChars = {  (char) 0x9, (char) 0xA, (char) 0xB, (char) 0xC, (char) 0xD, (char) 0x20, (char) 0xA0, (char) 0x2000, (char) 0x2001, (char) 0x2002, (char) 0x2003, (char) 0x2004, (char) 0x2005,
 187                                                                                                                                           (char) 0x2006, (char) 0x2007, (char) 0x2008, (char) 0x2009, (char) 0x200A, (char) 0x200B, (char) 0x3000, (char) 0xFEFF };
 188
 189                 public String Trim(params char[] chars) {
 190                         if (null == chars || chars.Length == 0)
 191                                 chars = WhiteChars;
 192
 193                         return InternalTrim(chars, 0);
 194                 }
 195
 196                 public String TrimStart(params char[] chars) {
 197                         if (null == chars || chars.Length == 0)
 198                                 chars = WhiteChars;
 199
 200                         return InternalTrim(chars, 1);
 201                 }
 202
 203                 public String TrimEnd(params char[] chars) {
 204                         if (null == chars || chars.Length == 0)
 205                                 chars = WhiteChars;
 206
 207                         return InternalTrim(chars, 2);
 208                 }
 209
 210                 public static int Compare(String s1, String s2) {
 211                         return Compare(s1, s2, false);
 212                 }
 213
 214                 public static int Compare(String s1, String s2, bool inCase) {
 215                         if (null == s1) {
 216                                 if (null == s2)
 217                                         return 0;
 218                                 else
 219                                         return -1;
 220                         } else if (null == s2)
 221                                 return 1;
 222
 223                         return InternalCompare(s1, 0, s2, 0, Math.Max(s1.length, s2.length), inCase);
 224                 }
 225
 226                 [MonoTODO()]
 227                 public static int Compare(String s1, String s2, bool inCase, CultureInfo culture) {
 228                         return Compare(s1, s2, inCase);
 229                 }
 230
 231                 public static int Compare(String s1, int i1, String s2, int i2, int length) {
 232                         return Compare(s1, i1, s2, i2, length, false);
 233                 }
 234
 235                 public static int Compare(String s1, int i1, String s2, int i2, int length, bool inCase) {
 236                         if (null == s1) {
 237                                 if (null == s2)
 238                                         return 0;
 239                                 else
 240                                         return -1;
 241                         } else if (null == s2)
 242                                 return 1;
 243
 244                         if (length < 0 || i1 < 0 || i2 < 0)
 245                                 throw new ArgumentOutOfRangeException ();
 246
 247                         if (i1 > s1.length || i2 > s2.length)
 248                                 throw new ArgumentOutOfRangeException ();
 249
 250                         if (length == 0)
 251                                 return 0;
 252
 253                         return InternalCompare(s1, i1, s2, i2, length, inCase);
 254                 }
 255
 256                 [MonoTODO()]
 257                 public static int Compare(String s1, int i1, String s2, int i2, int length, bool inCase, CultureInfo culture) {
 258                         return Compare(s1, i1, s2, i2, length, inCase);
 259                 }
 260
 261                 public int CompareTo(Object value) {
 262                         if (null == value)
 263                                 return 1;
 264
 265                         if (!(value is String))
 266                                 throw new ArgumentException();
 267
 268                         return String.Compare(this, (String) value, false);
 269                 }
 270
 271                 public int CompareTo(String str) {
 272                         if (null == str)
 273                                 return 1;
 274
 275                         return Compare(this, str, false);
 276                 }
 277
 278                 public static int CompareOrdinal(String s1, String s2) {
 279                         if (null == s1 || null == s2) {
 280                                 if ((Object)s1 == (Object) s2) {
 281                                         return 0;
 282                                 }
 283
 284                                 return (s1 == null) ? -1 : 1;
 285                         }
 286
 287                         return InternalCompare(s1, 0, s2, 0, Math.Max(s1.length, s2.length), false);
 288                 }
 289
 290                 public static int CompareOrdinal(String s1, int i1, String s2, int i2, int length) {
 291                         if (null == s1 || null == s2) {
 292                                 if ((Object)s1 == (Object) s2) {
 293                                         return 0;
 294                                 }
 295
 296                                 return (s1 == null) ? -1 : 1;
 297                         }
 298
 299                         if (i1 < 0 || i2 < 0 || length < 0)
 300                                 throw new ArgumentOutOfRangeException ();
 301
 302                         if (i1 > s1.length || i2 > s2.length)
 303                                 throw new ArgumentOutOfRangeException ();
 304
 305                         return InternalCompare(s1, i1, s2, i2, length, false);
 306                 }
 307
 308                 public bool EndsWith(String value) {
 309                         if (null == value)
 310                                 throw new ArgumentNullException();
 311
 312                         if (value.length > this.length) {
 313                                 return false;
 314                         }
 315
 316                         return (0 == Compare(this, length - value.length, value, 0, value.length));
 317                 }
 318
 319                 public int IndexOfAny(char [] arr) {
 320                         if (null == arr)
 321                                 throw new ArgumentNullException();
 322
 323                         return InternalIndexOfAny(arr, 0, this.length);
 324                 }
 325
 326                 public int IndexOfAny(char [] arr, int sindex) {
 327                         if (null == arr)
 328                                 throw new ArgumentNullException();
 329                         if (sindex < 0 || sindex >= this.length)
 330                                 throw new ArgumentOutOfRangeException();
 331
 332                         return InternalIndexOfAny(arr, sindex, this.length - sindex);
 333                 }
 334
 335                 public int IndexOfAny(char [] arr, int sindex, int count) {
 336                         if (null == arr)
 337                                 throw new ArgumentNullException();
 338                         if (sindex < 0 || count < 0 || sindex + count > this.length)
 339                                 throw new ArgumentOutOfRangeException ();
 340
 341                         return InternalIndexOfAny(arr, sindex, count);
 342                 }
 343
 344                 public int IndexOf(char value) {
 345                         return InternalIndexOf(value, 0, this.length);
 346                 }
 347
 348                 public int IndexOf(String value) {
 349                         return IndexOf(value, 0, this.length);
 350                 }
 351
 352                 public int IndexOf(char value, int sindex) {
 353                         if (sindex < 0 || sindex > this.length) {
 354                                 throw new ArgumentOutOfRangeException();
 355                         }
 356
 357                         if (sindex == this.length)
 358                                 return -1;
 359
 360                         return InternalIndexOf(value, sindex, this.length - sindex);
 361                 }
 362
 363                 public int IndexOf(String value, int sindex) {
 364                         if (sindex == this.length)
 365                                 return -1;
 366
 367                         return IndexOf(value, sindex, this.length - sindex);
 368                 }
 369
 370                 public int IndexOf(char value, int sindex, int count) {
 371                         if (sindex < 0 || count < 0 || sindex + count > this.length)
 372                                 throw new ArgumentOutOfRangeException ();
 373
 374                         if (sindex == 0 && this.length == 0)
 375                                 return -1;
 376
 377                         return InternalIndexOf(value, sindex, count);
 378                 }
 379
 380                 public int IndexOf(String value, int sindex, int count) {
 381                         if (null == value)
 382                                 throw new ArgumentNullException();
 383
 384                         if (sindex < 0 || count < 0 || sindex + count > this.length)
 385                                 throw new ArgumentOutOfRangeException ();
 386
 387                         if (sindex == 0 && this.length == 0)
 388                                 return -1;
 389
 390                         return InternalIndexOf(value, sindex, count);
 391                 }
 392
 393                 public int LastIndexOfAny(char [] arr) {
 394                         if (null == arr)
 395                                 throw new ArgumentNullException();
 396
 397                         return InternalLastIndexOfAny(arr, this.length - 1, this.length);
 398                 }
 399
 400                 public int LastIndexOfAny(char [] arr, int sindex) {
 401                         if (null == arr)
 402                                 throw new ArgumentNullException();
 403
 404                         if (sindex < 0 || sindex > this.length)
 405                                 throw new ArgumentOutOfRangeException();
 406
 407                         if (this.length == 0)
 408                                 return -1;
 409
 410                         return InternalLastIndexOfAny(arr, sindex, sindex + 1);
 411                 }
 412
 413                 public int LastIndexOfAny(char [] arr, int sindex, int count) {
 414                         if (null == arr)
 415                                 throw new ArgumentNullException();
 416
 417                         if (sindex < 0 || count < 0 || sindex > this.length || sindex - count < -1)
 418                                 throw new ArgumentOutOfRangeException();
 419
 420                         if (this.length == 0)
 421                                 return -1;
 422
 423                         return InternalLastIndexOfAny(arr, sindex, count);
 424                 }
 425
 426                 public int LastIndexOf(char value) {
 427                         return InternalLastIndexOf(value, this.length - 1, this.length);
 428                 }
 429
 430                 public int LastIndexOf(String value) {
 431                         if (null == value)
 432                                 throw new ArgumentNullException();
 433
 434                         if (value.length == 0)
 435                                 return 0;
 436
 437                         if (this.length == 0)
 438                                 return -1;
 439
 440                         return InternalLastIndexOf(value, this.length - 1, this.length);
 441                 }
 442
 443                 public int LastIndexOf(char value, int sindex){
 444                         return LastIndexOf(value, sindex, sindex + 1);
 445                 }
 446
 447                 public int LastIndexOf(String value, int sindex) {
 448                         return LastIndexOf(value, sindex, sindex + 1);
 449                 }
 450
 451                 public int LastIndexOf(char value, int sindex, int count) {
 452                         if (sindex < 0 || count < 0)
 453                                 throw new ArgumentOutOfRangeException ();
 454
 455                         if (sindex >= this.length || sindex - count + 1 < 0)
 456                                 throw new ArgumentOutOfRangeException ();
 457
 458                         if (sindex == 0 && this.length == 0)
 459                                 return -1;
 460
 461                         return InternalLastIndexOf(value, sindex, count);
 462                 }
 463
 464                 public int LastIndexOf(String value, int sindex, int count) {
 465                         if (null == value)
 466                                 throw new ArgumentNullException();
 467
 468                         if (sindex < 0 || sindex > this.length)
 469                                 throw new ArgumentOutOfRangeException ();
 470
 471                         if (count < 0 || sindex - count + 1 < 0)
 472                                 throw new ArgumentOutOfRangeException ();
 473
 474                         if (value.length > sindex)
 475                                 return -1;
 476
 477                         if (value == String.Empty)
 478                                 return sindex;
 479
 480                         if (sindex == 0 && this.length == 0)
 481                                 return -1;
 482
 483                         return InternalLastIndexOf(value, sindex, count);
 484                 }
 485
 486                 public String PadLeft(int width) {
 487                         return PadLeft(width, ' ');
 488                 }
 489
 490                 public String PadLeft(int width, char chr) {
 491                         if (width < 0)
 492                                 throw new ArgumentException();
 493
 494                         if (width < this.length)
 495                                 return String.Copy(this);
 496
 497                         return InternalPad(width, chr, false);
 498                 }
 499
 500                 public String PadRight(int width) {
 501                         return PadRight(width, ' ');
 502                 }
 503
 504                 public String PadRight(int width, char chr) {
 505                         if (width < 0)
 506                                 throw new ArgumentException();
 507
 508                         if (width < this.length)
 509                                 return String.Copy(this);
 510
 511                         return InternalPad(width, chr, true);
 512                 }
 513
 514                 public bool StartsWith(String value) {
 515                         if (null == value)
 516                                 throw new ArgumentNullException();
 517
 518                         if (this.length < value.length)
 519                                 return false;
 520
 521                         return (0 == Compare(this, 0, value, 0 , value.length));
 522                 }
 523
 524
 525                 public String Replace (char oldChar, char newChar) {
 526                         return InternalReplace(oldChar, newChar);
 527                 }
 528
 529                 public String Replace(String oldValue, String newValue) {
 530                         if (null == oldValue)
 531                                 throw new ArgumentNullException();
 532
 533                         return InternalReplace(oldValue, newValue);
 534                 }
 535
 536                 public String Remove(int sindex, int count) {
 537                         if (sindex < 0 || count < 0 || sindex + count > this.length)
 538                                 throw new ArgumentOutOfRangeException ();
 539
 540                         return InternalRemove(sindex, count);
 541                 }
 542
 543                 public String ToLower() {
 544                         return InternalToLower();
 545                 }
 546
 547                 public String ToLower(CultureInfo culture) {
 548                         throw new NotImplementedException();
 549                 }
 550
 551                 public String ToUpper() {
 552                         return InternalToUpper();
 553                 }
 554
 555                 public String ToUpper(CultureInfo culture) {
 556                         throw new NotImplementedException();
 557                 }
 558
 559                 public override String ToString() {
 560                         return this;
 561                 }
 562
 563                 public String ToString(IFormatProvider provider) {
 564                         return this;
 565                 }
 566
 567                 public String Trim() {
 568                         return Trim(null);
 569                 }
 570
 571                 public static String Format(String format, Object arg0) {
 572                         return Format(null, format, new Object[] {arg0});
 573                 }
 574
 575                 public static String Format(String format, Object arg0, Object arg1) {
 576                         return Format(null, format, new Object[] {arg0, arg1});
 577                 }
 578
 579                 public static String Format(String format, Object arg0, Object arg1, Object arg2) {
 580                         return Format(null, format, new Object[] {arg0, arg1, arg2});
 581                 }
 582
 583                 public static string Format (string format, params object[] args) {
 584                         return Format (null, format, args);
 585                 }
 586
 587                 public static string Format (IFormatProvider provider, string format, params object[] args) {
 588                         if (format == null || args == null)
 589                                 throw new ArgumentNullException ();
 590
 591                         StringBuilder result = new StringBuilder ();
 592
 593                         int ptr = 0;
 594                         int start = ptr;
 595                         while (ptr < format.length) {
 596                                 char c = format[ptr ++];
 597
 598                                 if (c == '{') {
 599                                         result.Append (format, start, ptr - start - 1);
 600
 601                                         // check for escaped open bracket
 602
 603                                         if (format[ptr] == '{') {
 604                                                 start = ptr ++;
 605                                                 continue;
 606                                         }
 607
 608                                         // parse specifier
 609
 610                                         int n, width;
 611                                         bool left_align;
 612                                         string arg_format;
 613
 614                                         ParseFormatSpecifier (format, ref ptr, out n, out width, out left_align, out arg_format);
 615                                         if (n >= args.Length)
 616                                                 throw new FormatException ("Index (zero based) must be greater than or equal to zero and less than the size of the argument list.");
 617
 618                                         // format argument
 619
 620                                         object arg = args[n];
 621
 622                                         string str;
 623                                         if (arg == null)
 624                                                 str = "";
 625                                         else if (arg is IFormattable)
 626                                                 str = ((IFormattable)arg).ToString (arg_format, provider);
 627                                         else
 628                                                 str = arg.ToString ();
 629
 630                                         // pad formatted string and append to result
 631
 632                                         if (width > str.length) {
 633                                                 string pad = new String (' ', width - str.length);
 634
 635                                                 if (left_align) {
 636                                                         result.Append (str);
 637                                                         result.Append (pad);
 638                                                 }
 639                                                 else {
 640                                                         result.Append (pad);
 641                                                         result.Append (str);
 642                                                 }
 643                                         }
 644                                         else
 645                                                 result.Append (str);
 646
 647                                         start = ptr;
 648                                 }
 649                                 else if (c == '}' && format[ptr] == '}') {
 650                                         result.Append (format, start, ptr - start - 1);
 651                                         start = ptr ++;
 652                                 }
 653                         }
 654
 655                         if (start < format.length)
 656                                 result.Append (format.Substring (start));
 657
 658                         return result.ToString ();
 659                 }
 660
 661                 public static String Copy (String str) {
 662                         if (str == null)
 663                                 throw new ArgumentNullException ();
 664
 665                         int length = str.length;
 666
 667                         String tmp = InternalAllocateStr(length);
 668                         InternalStrcpy(tmp, 0, str);
 669                         return tmp;
 670                 }
 671
 672                 public static String Concat(Object obj) {
 673                         if (null == obj)
 674                                 return String.Empty;
 675
 676                         return obj.ToString();
 677                 }
 678
 679                 public static String Concat(Object obj1, Object obj2) {
 680                         if (null == obj1)
 681                                 obj1 = String.Empty;
 682
 683                         if (null == obj2)
 684                                 obj2 = String.Empty;
 685
 686                         return Concat(obj1.ToString(), obj2.ToString());
 687                 }
 688
 689                 public static String Concat(Object obj1, Object obj2, Object obj3) {
 690                         if (null == obj1)
 691                                 obj1 = String.Empty;
 692
 693                         if (null == obj2)
 694                                 obj2 = String.Empty;
 695
 696                         if (null == obj3)
 697                                 obj3 = String.Empty;
 698
 699                         return Concat(obj1.ToString(), obj2.ToString(), obj3.ToString());
 700                 }
 701
 702                 public static String Concat(String s1, String s2) {
 703                         if (null == s1) {
 704                                 if (null == s2) { return String.Empty; }
 705                                 return s2;
 706                         }
 707
 708                         if (null == s2) { return s1; }
 709
 710                         String tmp = InternalAllocateStr(s1.length + s2.length);
 711
 712                         InternalStrcpy(tmp, 0, s1);
 713                         InternalStrcpy(tmp, s1.length, s2);
 714
 715                         return tmp;
 716                 }
 717
 718                 public static String Concat(String s1, String s2, String s3) {
 719                         if (null == s1 && null == s2 && null == s3) {
 720                                 return String.Empty;
 721                         }
 722
 723                         if (null == s1) { s1 = String.Empty; }
 724                         if (null == s2) { s2 = String.Empty; }
 725                         if (null == s3) { s3 = String.Empty; }
 726
 727                         String tmp = InternalAllocateStr(s1.length + s2.length + s3.length);
 728
 729                         InternalStrcpy(tmp, 0, s1);
 730                         InternalStrcpy(tmp, s1.length, s2);
 731                         InternalStrcpy(tmp, s1.length + s2.length, s3);
 732
 733                         return tmp;
 734                 }
 735
 736                 public static String Concat(String s1, String s2, String s3, String s4) {
 737                         if (null == s1 && null == s2 && null == s3 && null == s4) {
 738                                 return String.Empty;
 739                         }
 740
 741                         if (null == s1) { s1 = String.Empty; }
 742                         if (null == s2) { s2 = String.Empty; }
 743                         if (null == s3) { s3 = String.Empty; }
 744                         if (null == s4) { s4 = String.Empty; }
 745
 746                         String tmp = InternalAllocateStr(s1.length + s2.length + s3.length + s4.length);
 747
 748                         InternalStrcpy(tmp, 0, s1);
 749                         InternalStrcpy(tmp, s1.length, s2);
 750                         InternalStrcpy(tmp, s1.length + s2.length, s3);
 751                         InternalStrcpy(tmp, s1.length + s2.length + s3.length, s4);
 752
 753                         return tmp;
 754                 }
 755
 756                 public static String Concat(params Object[] args) {
 757                         string [] strings;
 758                         int len, i, currentpos;
 759
 760                         if (null == args)
 761                                 throw new ArgumentNullException ();
 762
 763                         strings = new string [args.Length];
 764                         len = 0;
 765                         i = 0;
 766                         foreach (object arg in args) {
 767                                 /* use Empty for each null argument */
 768                                 if (arg == null)
 769                                         strings[i] = String.Empty;
 770                                 else
 771                                         strings[i] = arg.ToString ();
 772                                 len += strings[i].length;
 773                                 i++;
 774                         }
 775
 776                         if (len == 0)
 777                                 return String.Empty;
 778
 779                         currentpos = 0;
 780
 781                         String tmp = InternalAllocateStr(len);
 782                         for (i = 0; i < strings.Length; i++) {
 783                                 InternalStrcpy(tmp, currentpos, strings[i]);
 784                                 currentpos += strings[i].length;
 785                         }
 786
 787                         return tmp;
 788                 }
 789
 790                 public static String Concat(params String[] values) {
 791                         int len, i, currentpos;
 792
 793                         if (values == null)
 794                                 throw new ArgumentNullException ();
 795
 796                         len = 0;
 797                         foreach (string value in values)
 798                                 len += value != null ? value.length : 0;
 799
 800                         if (len == 0)
 801                                 return String.Empty;
 802
 803                         currentpos = 0;
 804
 805                         String tmp = InternalAllocateStr(len);
 806                         for (i = 0; i < values.Length; i++) {
 807                                 if (values[i] == null)
 808                                         continue;
 809
 810                                 InternalStrcpy(tmp, currentpos, values[i]);
 811                                 currentpos += values[i].length;
 812                         }
 813
 814                         return tmp;
 815                 }
 816
 817                 public String Insert(int sindex, String value) {
 818                         if (null == value)
 819                                 throw new ArgumentNullException();
 820
 821                         if (sindex < 0 || sindex > this.length)
 822                                 throw new ArgumentOutOfRangeException();
 823
 824                         return InternalInsert(sindex, value);
 825                 }
 826
 827
 828                 public static string Intern (string str) {
 829                         if (null == str)
 830                                 throw new ArgumentNullException ();
 831
 832                         return InternalIntern(str);
 833                 }
 834
 835                 public static string IsInterned (string str) {
 836                         if (null == str)
 837                                 throw new ArgumentNullException();
 838
 839                         return InternalIsInterned(str);
 840                 }
 841
 842                 public static string Join (string separator, string [] value) {
 843                         if (value == null)
 844                                 throw new ArgumentNullException ();
 845
 846                         return Join(separator, value, 0, value.Length);
 847                 }
 848
 849                 public static string Join(string separator, string[] value, int sindex, int count) {
 850                         if (value == null)
 851                                 throw new ArgumentNullException ();
 852
 853                         if (sindex + count > value.Length)
 854                                 throw new ArgumentOutOfRangeException ();
 855
 856                         if (sindex == value.Length)
 857                                 return String.Empty;
 858
 859                         return InternalJoin(separator, value, sindex, count);
 860                 }
 861
 862                 bool IConvertible.ToBoolean (IFormatProvider provider) {
 863                         return Convert.ToBoolean (this);
 864                 }
 865
 866                 byte IConvertible.ToByte (IFormatProvider provider) {
 867                         return Convert.ToByte (this);
 868                 }
 869
 870                 char IConvertible.ToChar (IFormatProvider provider) {
 871                         return Convert.ToChar (this);
 872                 }
 873
 874                 DateTime IConvertible.ToDateTime (IFormatProvider provider) {
 875                         return Convert.ToDateTime (this);
 876                 }
 877
 878                 decimal IConvertible.ToDecimal (IFormatProvider provider) {
 879                         return Convert.ToDecimal (this);
 880                 }
 881
 882                 double IConvertible.ToDouble (IFormatProvider provider) {
 883                         return Convert.ToDouble (this);
 884                 }
 885
 886                 short IConvertible.ToInt16 (IFormatProvider provider) {
 887                         return Convert.ToInt16 (this);
 888                 }
 889
 890                 int IConvertible.ToInt32 (IFormatProvider provider) {
 891                         return Convert.ToInt32 (this);
 892                 }
 893
 894                 long IConvertible.ToInt64 (IFormatProvider provider) {
 895                         return Convert.ToInt64 (this);
 896                 }
 897
 898                 [CLSCompliant(false)]
 899                 sbyte IConvertible.ToSByte (IFormatProvider provider) {
 900                         return Convert.ToSByte (this);
 901                 }
 902
 903                 float IConvertible.ToSingle (IFormatProvider provider) {
 904                         return Convert.ToSingle (this);
 905                 }
 906                 string IConvertible.ToString (IFormatProvider format) {
 907                         return this;
 908                 }
 909
 910                 object IConvertible.ToType (Type conversionType, IFormatProvider provider) {
 911                         return Convert.ToType (this, conversionType,  provider);
 912                 }
 913
 914                 [CLSCompliant(false)]
 915                 ushort IConvertible.ToUInt16 (IFormatProvider provider) {
 916                         return Convert.ToUInt16 (this);
 917                 }
 918
 919                 [CLSCompliant(false)]
 920                 uint IConvertible.ToUInt32 (IFormatProvider provider) {
 921                         return Convert.ToUInt32 (this);
 922                 }
 923
 924                 [CLSCompliant(false)]
 925                 ulong IConvertible.ToUInt64 (IFormatProvider provider) {
 926                         return Convert.ToUInt64 (this);
 927                 }
 928
 929                 TypeCode IConvertible.GetTypeCode () {
 930                         return TypeCode.String;
 931                 }
 932
 933                 public int Length {
 934                         get {
 935                                 return length;
 936                         }
 937                 }
 938
 939                 public CharEnumerator GetEnumerator () {
 940                         return new CharEnumerator (this);
 941                 }
 942
 943                 IEnumerator IEnumerable.GetEnumerator () {
 944                         return new CharEnumerator (this);
 945                 }
 946
 947                 private static void ParseFormatSpecifier (string str, ref int ptr, out int n, out int width, out bool left_align, out string format) {
 948                         // parses format specifier of form:
 949                         //   N,[[-]M][:F]}
 950                         //
 951                         // where:
 952
 953                         try {
 954                                 // N = argument number (non-negative integer)
 955
 956                                 n = ParseDecimal (str, ref ptr);
 957                                 if (n < 0)
 958                                         throw new FormatException ("Input string was not in correct format.");
 959
 960                                 // M = width (non-negative integer)
 961
 962                                 if (str[ptr] == ',') {
 963                                         left_align = (str[++ ptr] == '-');
 964                                         if (left_align)
 965                                                 ++ ptr;
 966
 967                                         width = ParseDecimal (str, ref ptr);
 968                                         if (width < 0)
 969                                                 throw new FormatException ("Input string was not in correct format.");
 970                                 }
 971                                 else {
 972                                         width = 0;
 973                                         left_align = false;
 974                                 }
 975
 976                                 // F = argument format (string)
 977
 978                                 if (str[ptr] == ':') {
 979                                         int start = ++ ptr;
 980                                         while (str[ptr] != '}')
 981                                                 ++ ptr;
 982
 983                                         format = str.Substring (start, ptr - start);
 984                                 }
 985                                 else
 986                                         format = null;
 987
 988                                 if (str[ptr ++] != '}')
 989                                         throw new FormatException ("Input string was not in correct format.");
 990                         }
 991                         catch (IndexOutOfRangeException) {
 992                                 throw new FormatException ("Input string was not in correct format.");
 993                         }
 994                 }
 995
 996                 private static int ParseDecimal (string str, ref int ptr) {
 997                         int p = ptr;
 998                         int n = 0;
 999                         while (true) {
1000                                 char c = str[p];
1001                                 if (c < '0' || '9' < c)
1002                                         break;
1003
1004                                 n = n * 10 + c - '0';
1005                                 ++ p;
1006                         }
1007
1008                         if (p == ptr)
1009                                 return -1;
1010
1011                         ptr = p;
1012                         return n;
1013                 }
1014
1015                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
1016                 private extern static string InternalJoin(string separator, string[] value, int sindex, int count);
1017
1018                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
1019                 private extern String InternalInsert(int sindex, String value);
1020
1021                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
1022                 private extern String InternalReplace(char oldChar, char newChar);
1023
1024                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
1025                 private extern String InternalReplace(String oldValue, String newValue);
1026
1027                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
1028                 private extern String InternalRemove(int sindex, int count);
1029
1030                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
1031                 private extern void InternalCopyTo(int sindex, char[] dest, int dindex, int count);
1032
1033                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
1034                 private extern String[] InternalSplit(char[] separator, int count);
1035
1036                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
1037                 private extern String InternalTrim(char[] chars, int typ);
1038
1039                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
1040                 private extern int InternalIndexOf(char value, int sindex, int count);
1041
1042                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
1043                 private extern int InternalIndexOf(string value, int sindex, int count);
1044
1045                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
1046                 private extern int InternalIndexOfAny(char [] arr, int sindex, int count);
1047
1048                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
1049                 private extern int InternalLastIndexOf(char value, int sindex, int count);
1050
1051                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
1052                 private extern int InternalLastIndexOf(String value, int sindex, int count);
1053
1054                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
1055                 private extern int InternalLastIndexOfAny(char [] anyOf, int sindex, int count);
1056
1057                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
1058                 private extern String InternalPad(int width, char chr, bool right);
1059
1060                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
1061                 private extern String InternalToLower();
1062
1063                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
1064                 private extern String InternalToUpper();
1065
1066                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
1067                 private extern static String InternalAllocateStr(int length);
1068
1069                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
1070                 private extern static void InternalStrcpy(String dest, int destPos, String src);
1071
1072                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
1073                 private extern static void InternalStrcpy(String dest, int destPos, String src, int startPos, int count);
1074
1075                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
1076                 private extern static string InternalIntern(string str);
1077
1078                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
1079                 private extern static string InternalIsInterned(string str);
1080
1081                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
1082                 private extern static int InternalCompare(String s1, int i1, String s2, int i2, int length, bool inCase);
1083
1084                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
1085                 private extern static bool InternalEquals(String s1, String s2);
1086         }
1087 }