mcs/class/corlib/System.Text/StringBuilder.cs

   1 // -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*-
   2 //
   3 // System.Text.StringBuilder
   4 //
   5 // Authors:
   6 //   Marcin Szczepanski (marcins@zipworld.com.au)
   7 //   Paolo Molaro (lupus@ximian.com)
   8 //   Patrik Torstensson
   9 //
  10 // NOTE: In the case the buffer is only filled by 50% a new string
  11 //       will be returned by ToString() is cached in the '_cached_str'
  12 //               cache_string will also control if a string has been handed out
  13 //               to via ToString(). If you are chaning the code make sure that
  14 //               if you modify the string data set the cache_string to null.
  15 //
  16
  17 //
  18 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
  19 //
  20 // Permission is hereby granted, free of charge, to any person obtaining
  21 // a copy of this software and associated documentation files (the
  22 // "Software"), to deal in the Software without restriction, including
  23 // without limitation the rights to use, copy, modify, merge, publish,
  24 // distribute, sublicense, and/or sell copies of the Software, and to
  25 // permit persons to whom the Software is furnished to do so, subject to
  26 // the following conditions:
  27 //
  28 // The above copyright notice and this permission notice shall be
  29 // included in all copies or substantial portions of the Software.
  30 //
  31 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  32 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  33 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  34 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  35 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  36 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  37 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  38 //
  39 using System.Runtime.Serialization;
  40 using System.Runtime.CompilerServices;
  41 using System.Runtime.InteropServices;
  42
  43 namespace System.Text {
  44
  45         [Serializable]
  46 #if NET_2_0
  47         [ComVisible (true)]
  48 #endif
  49         [MonoTODO ("Serialization format not compatible with .NET")]
  50         public sealed class StringBuilder
  51 #if NET_2_0
  52                 : ISerializable
  53 #endif
  54         {
  55                 private int _length;
  56                 private string _str;
  57                 private string _cached_str;
  58
  59                 private int _maxCapacity = Int32.MaxValue;
  60                 private const int constDefaultCapacity = 16;
  61
  62                 public StringBuilder(string value, int startIndex, int length, int capacity)
  63                 {
  64                         // first, check the parameters and throw appropriate exceptions if needed
  65                         if (null == value)
  66                                 value = "";
  67
  68                         // make sure startIndex is zero or positive
  69                         if (startIndex < 0)
  70                                 throw new System.ArgumentOutOfRangeException ("startIndex", startIndex, "StartIndex cannot be less than zero.");
  71
  72                         // make sure length is zero or positive
  73                         if(length < 0)
  74                                 throw new System.ArgumentOutOfRangeException ("length", length, "Length cannot be less than zero.");
  75
  76                         if (capacity < 0)
  77                                 throw new System.ArgumentOutOfRangeException ("capacity", capacity, "capacity must be greater than zero.");
  78
  79                         // make sure startIndex and length give a valid substring of value
  80                         // re-ordered to avoid possible integer overflow
  81                         if (startIndex > value.Length - length)
  82                                 throw new System.ArgumentOutOfRangeException ("startIndex", startIndex, "StartIndex and length must refer to a location within the string.");
  83
  84                         if (capacity == 0)
  85                                 capacity = constDefaultCapacity;
  86
  87                         _str = String.InternalAllocateStr ((length > capacity) ? length : capacity);
  88                         if (length > 0)
  89                                 String.CharCopy (_str, 0, value, startIndex, length);
  90
  91                         _length = length;
  92                 }
  93
  94                 public StringBuilder () : this (null) {}
  95
  96                 public StringBuilder(int capacity) : this (String.Empty, 0, 0, capacity) {}
  97
  98                 public StringBuilder(int capacity, int maxCapacity) : this (String.Empty, 0, 0, capacity) {
  99                         if (maxCapacity < 1)
 100                                 throw new System.ArgumentOutOfRangeException ("maxCapacity", "maxCapacity is less than one.");
 101                         if (capacity > maxCapacity)
 102                                 throw new System.ArgumentOutOfRangeException ("capacity", "Capacity exceeds maximum capacity.");
 103
 104                         _maxCapacity = maxCapacity;
 105                 }
 106
 107                 public StringBuilder (string value)
 108                 {
 109                         /*
 110                          * This is an optimization to avoid allocating the internal string
 111                          * until the first Append () call.
 112                          * The runtime pinvoke marshalling code needs to be aware of this.
 113                          */
 114                         if (null == value)
 115                                 value = "";
 116
 117                         _length = value.Length;
 118                         _str = _cached_str = value;
 119                 }
 120
 121                 public StringBuilder( string value, int capacity) : this(value, 0, value.Length, capacity) {}
 122
 123                 public int MaxCapacity {
 124                         get {
 125                                 // MS runtime always returns Int32.MaxValue.
 126                                 return _maxCapacity;
 127                         }
 128                 }
 129
 130                 public int Capacity {
 131                         get {
 132                                 if (_str.Length == 0)
 133                                         return constDefaultCapacity;
 134
 135                                 return _str.Length;
 136                         }
 137
 138                         set {
 139                                 if (value < _length)
 140                                         throw new ArgumentException( "Capacity must be larger than length" );
 141
 142                                 InternalEnsureCapacity(value);
 143                         }
 144                 }
 145
 146                 public int Length {
 147                         get {
 148                                 return _length;
 149                         }
 150
 151                         set {
 152                                 if( value < 0 || value > _maxCapacity)
 153                                         throw new ArgumentOutOfRangeException();
 154
 155                                 if (value == _length)
 156                                         return;
 157
 158                                 if (value < _length) {
 159                                         // LAMESPEC:  The spec is unclear as to what to do
 160                                         // with the capacity when truncating the string.
 161
 162                                         // Do as MS, keep the capacity
 163
 164                                         // Make sure that we invalidate any cached string.
 165                                         InternalEnsureCapacity (value);
 166                                         _length = value;
 167                                 } else {
 168                                         // Expand the capacity to the new length and
 169                                         // pad the string with NULL characters.
 170                                         Append('\0', value - _length);
 171                                 }
 172                         }
 173                 }
 174
 175                 [IndexerName("Chars")]
 176                 public char this [int index] {
 177                         get {
 178                                 if (index >= _length || index < 0)
 179                                         throw new IndexOutOfRangeException();
 180
 181                                 return _str [index];
 182                         }
 183
 184                         set {
 185                                 if (index >= _length || index < 0)
 186                                         throw new IndexOutOfRangeException();
 187
 188                                 if (null != _cached_str)
 189                                         InternalEnsureCapacity (_length);
 190
 191                                 _str.InternalSetChar (index, value);
 192                         }
 193                 }
 194
 195                 public override string ToString ()
 196                 {
 197                         if (_length == 0)
 198                                 return String.Empty;
 199
 200                         if (null != _cached_str)
 201                                 return _cached_str;
 202
 203                         // If we only have a half-full buffer we return a new string.
 204                         if (_length < (_str.Length >> 1))
 205                         {
 206                                 // use String.SubstringUnchecked instead of String.Substring
 207                                 // as the former is guaranteed to create a new string object
 208                                 _cached_str = _str.SubstringUnchecked (0, _length);
 209                                 return _cached_str;
 210                         }
 211
 212                         _cached_str = _str;
 213                         _str.InternalSetLength(_length);
 214
 215                         return _str;
 216                 }
 217
 218                 public string ToString (int startIndex, int length)
 219                 {
 220                         // re-ordered to avoid possible integer overflow
 221                         if (startIndex < 0 || length < 0 || startIndex > _length - length)
 222                                 throw new ArgumentOutOfRangeException();
 223
 224                         // use String.SubstringUnchecked instead of String.Substring
 225                         // as the former is guaranteed to create a new string object
 226                         if (startIndex == 0 && length == _length)
 227                                 return ToString ();
 228                         else
 229                                 return _str.SubstringUnchecked (startIndex, length);
 230                 }
 231
 232                 public int EnsureCapacity (int capacity)
 233                 {
 234                         if (capacity < 0)
 235                                 throw new ArgumentOutOfRangeException ("Capacity must be greater than 0." );
 236
 237                         if( capacity <= _str.Length )
 238                                 return _str.Length;
 239
 240                         InternalEnsureCapacity (capacity);
 241
 242                         return _str.Length;
 243                 }
 244
 245                 public bool Equals (StringBuilder sb)
 246                 {
 247                         if (((object)sb) == null)
 248                                 return false;
 249
 250                         if (_length == sb.Length && _str == sb._str )
 251                                 return true;
 252
 253                         return false;
 254                 }
 255
 256                 public StringBuilder Remove (int startIndex, int length)
 257                 {
 258                         // re-ordered to avoid possible integer overflow
 259                         if (startIndex < 0 || length < 0 || startIndex > _length - length)
 260                                 throw new ArgumentOutOfRangeException();
 261
 262                         if (null != _cached_str)
 263                                 InternalEnsureCapacity (_length);
 264
 265                         // Copy everything after the 'removed' part to the start
 266                         // of the removed part and truncate the sLength
 267                         if (_length - (startIndex + length) > 0)
 268                                 String.CharCopy (_str, startIndex, _str, startIndex + length, _length - (startIndex + length));
 269
 270                         _length -= length;
 271
 272                         return this;
 273                 }
 274
 275                 public StringBuilder Replace (char oldChar, char newChar)
 276                 {
 277                         return Replace( oldChar, newChar, 0, _length);
 278                 }
 279
 280                 public StringBuilder Replace (char oldChar, char newChar, int startIndex, int count)
 281                 {
 282                         // re-ordered to avoid possible integer overflow
 283                         if (startIndex > _length - count || startIndex < 0 || count < 0)
 284                                 throw new ArgumentOutOfRangeException();
 285
 286                         if (null != _cached_str)
 287                                 InternalEnsureCapacity (_str.Length);
 288
 289                         for (int replaceIterate = startIndex; replaceIterate < startIndex + count; replaceIterate++ ) {
 290                                 if( _str [replaceIterate] == oldChar )
 291                                         _str.InternalSetChar (replaceIterate, newChar);
 292                         }
 293
 294                         return this;
 295                 }
 296
 297                 public StringBuilder Replace( string oldValue, string newValue ) {
 298                         return Replace (oldValue, newValue, 0, _length);
 299                 }
 300
 301                 public StringBuilder Replace( string oldValue, string newValue, int startIndex, int count )
 302                 {
 303                         if (oldValue == null)
 304                                 throw new ArgumentNullException ("The old value cannot be null.");
 305
 306                         if (startIndex < 0 || count < 0 || startIndex > _length - count)
 307                                 throw new ArgumentOutOfRangeException ();
 308
 309                         if (oldValue.Length == 0)
 310                                 throw new ArgumentException ("The old value cannot be zero length.");
 311
 312                         // TODO: OPTIMIZE!
 313                         string replace = _str.Substring(startIndex, count).Replace(oldValue, newValue);
 314
 315                         InternalEnsureCapacity (replace.Length + (_length - count));
 316
 317                         string end = _str.Substring (startIndex + count, _length - startIndex - count );
 318
 319                         String.CharCopy (_str, startIndex, replace, 0, replace.Length);
 320                         String.CharCopy (_str, startIndex + replace.Length, end, 0, end.Length);
 321
 322                         _length = replace.Length + (_length - count);
 323
 324                         return this;
 325                 }
 326
 327
 328                 /* The Append Methods */
 329                 public StringBuilder Append (char[] value)
 330                 {
 331                         if (value == null)
 332                                 return this;
 333
 334                         int needed_cap = _length + value.Length;
 335                         if (null != _cached_str || _str.Length < needed_cap)
 336                                 InternalEnsureCapacity (needed_cap);
 337
 338                         String.CharCopy (_str, _length, value, 0, value.Length);
 339                         _length = needed_cap;
 340
 341                         return this;
 342                 }
 343
 344                 public StringBuilder Append (string value)
 345                 {
 346                         if (value == null)
 347                                 return this;
 348
 349                         if (_length == 0 && value.Length < _maxCapacity && value.Length > _str.Length) {
 350                                 _length = value.Length;
 351                                 _str = _cached_str = value;
 352                                 return this;
 353                         }
 354
 355                         int needed_cap = _length + value.Length;
 356                         if (null != _cached_str || _str.Length < needed_cap)
 357                                 InternalEnsureCapacity (needed_cap);
 358
 359                         String.CharCopy (_str, _length, value, 0, value.Length);
 360                         _length = needed_cap;
 361                         return this;
 362                 }
 363
 364                 public StringBuilder Append (bool value) {
 365                         return Append (value.ToString());
 366                 }
 367
 368                 public StringBuilder Append (byte value) {
 369                         return Append (value.ToString());
 370                 }
 371
 372                 public StringBuilder Append (decimal value) {
 373                         return Append (value.ToString());
 374                 }
 375
 376                 public StringBuilder Append (double value) {
 377                         return Append (value.ToString());
 378                 }
 379
 380                 public StringBuilder Append (short value) {
 381                         return Append (value.ToString());
 382                 }
 383
 384                 public StringBuilder Append (int value) {
 385                         return Append (value.ToString());
 386                 }
 387
 388                 public StringBuilder Append (long value) {
 389                         return Append (value.ToString());
 390                 }
 391
 392                 public StringBuilder Append (object value) {
 393                         if (value == null)
 394                                 return this;
 395
 396                         return Append (value.ToString());
 397                 }
 398
 399                 [CLSCompliant(false)]
 400                 public StringBuilder Append (sbyte value) {
 401                         return Append (value.ToString());
 402                 }
 403
 404                 public StringBuilder Append (float value) {
 405                         return Append (value.ToString());
 406                 }
 407
 408                 [CLSCompliant(false)]
 409                 public StringBuilder Append (ushort value) {
 410                         return Append (value.ToString());
 411                 }
 412
 413                 [CLSCompliant(false)]
 414                 public StringBuilder Append (uint value) {
 415                         return Append (value.ToString());
 416                 }
 417
 418                 [CLSCompliant(false)]
 419                 public StringBuilder Append (ulong value) {
 420                         return Append (value.ToString());
 421                 }
 422
 423                 public StringBuilder Append (char value)
 424                 {
 425                         int needed_cap = _length + 1;
 426                         if (null != _cached_str || _str.Length < needed_cap)
 427                                 InternalEnsureCapacity (needed_cap);
 428
 429                         _str.InternalSetChar(_length, value);
 430                         _length = needed_cap;
 431
 432                         return this;
 433                 }
 434
 435                 public StringBuilder Append (char value, int repeatCount)
 436                 {
 437                         if( repeatCount < 0 )
 438                                 throw new ArgumentOutOfRangeException();
 439
 440                         InternalEnsureCapacity (_length + repeatCount);
 441
 442                         for (int i = 0; i < repeatCount; i++)
 443                                 _str.InternalSetChar (_length++, value);
 444
 445                         return this;
 446                 }
 447
 448                 public StringBuilder Append( char[] value, int startIndex, int charCount )
 449                 {
 450                         if (value == null) {
 451                                 if (!(startIndex == 0 && charCount == 0))
 452                                         throw new ArgumentNullException ("value");
 453
 454                                 return this;
 455                         }
 456
 457                         if ((charCount < 0 || startIndex < 0) || (startIndex > value.Length - charCount))
 458                                 throw new ArgumentOutOfRangeException();
 459
 460                         int needed_cap = _length + charCount;
 461                         InternalEnsureCapacity (needed_cap);
 462
 463                         String.CharCopy (_str, _length, value, startIndex, charCount);
 464                         _length = needed_cap;
 465
 466                         return this;
 467                 }
 468
 469                 public StringBuilder Append (string value, int startIndex, int count)
 470                 {
 471                         if (value == null) {
 472                                 if (startIndex != 0 && count != 0)
 473                                         throw new ArgumentNullException ("value");
 474
 475                                 return this;
 476                         }
 477
 478                         if ((count < 0 || startIndex < 0) || (startIndex > value.Length - count))
 479                                 throw new ArgumentOutOfRangeException();
 480
 481                         int needed_cap = _length + count;
 482                         if (null != _cached_str || _str.Length < needed_cap)
 483                                 InternalEnsureCapacity (needed_cap);
 484
 485                         String.CharCopy (_str, _length, value, startIndex, count);
 486
 487                         _length = needed_cap;
 488
 489                         return this;
 490                 }
 491
 492 #if NET_2_0
 493                 [ComVisible (false)]
 494                 public StringBuilder AppendLine ()
 495                 {
 496                         return Append (System.Environment.NewLine);
 497                 }
 498
 499                 [ComVisible (false)]
 500                 public StringBuilder AppendLine (string value)
 501                 {
 502                         return Append (value).Append (System.Environment.NewLine);
 503                 }
 504 #endif
 505
 506                 public StringBuilder AppendFormat (string format, params object[] args)
 507                 {
 508                         return AppendFormat (null, format, args);
 509                 }
 510
 511                 public StringBuilder AppendFormat (IFormatProvider provider,
 512                                                    string format,
 513                                                    params object[] args)
 514                 {
 515                         String.FormatHelper (this, provider, format, args);
 516                         return this;
 517                 }
 518
 519 #if NET_2_1
 520                 internal
 521 #else
 522                 public
 523 #endif
 524                 StringBuilder AppendFormat (string format, object arg0)
 525                 {
 526                         return AppendFormat (null, format, new object [] { arg0 });
 527                 }
 528
 529 #if NET_2_1
 530                 internal
 531 #else
 532                 public
 533 #endif
 534                 StringBuilder AppendFormat (string format, object arg0, object arg1)
 535                 {
 536                         return AppendFormat (null, format, new object [] { arg0, arg1 });
 537                 }
 538
 539 #if NET_2_1
 540                 internal
 541 #else
 542                 public
 543 #endif
 544                 StringBuilder AppendFormat (string format, object arg0, object arg1, object arg2)
 545                 {
 546                         return AppendFormat (null, format, new object [] { arg0, arg1, arg2 });
 547                 }
 548
 549                 /*  The Insert Functions */
 550
 551                 public StringBuilder Insert (int index, char[] value)
 552                 {
 553                         return Insert (index, new string (value));
 554                 }
 555
 556                 public StringBuilder Insert (int index, string value)
 557                 {
 558                         if( index > _length || index < 0)
 559                                 throw new ArgumentOutOfRangeException();
 560
 561                         if (value == null || value.Length == 0)
 562                                 return this;
 563
 564                         InternalEnsureCapacity (_length + value.Length);
 565
 566                         // Move everything to the right of the insert point across
 567                         String.CharCopyReverse (_str, index + value.Length, _str, index, _length - index);
 568
 569                         // Copy in stuff from the insert buffer
 570                         String.CharCopy (_str, index, value, 0, value.Length);
 571
 572                         _length += value.Length;
 573
 574                         return this;
 575                 }
 576
 577                 public StringBuilder Insert( int index, bool value ) {
 578                         return Insert (index, value.ToString());
 579                 }
 580
 581                 public StringBuilder Insert( int index, byte value ) {
 582                         return Insert (index, value.ToString());
 583                 }
 584
 585                 public StringBuilder Insert( int index, char value)
 586                 {
 587                         if (index > _length || index < 0)
 588                                 throw new ArgumentOutOfRangeException ("index");
 589
 590                         InternalEnsureCapacity (_length + 1);
 591
 592                         // Move everything to the right of the insert point across
 593                         String.CharCopyReverse (_str, index + 1, _str, index, _length - index);
 594
 595                         _str.InternalSetChar (index, value);
 596                         _length++;
 597
 598                         return this;
 599                 }
 600
 601                 public StringBuilder Insert( int index, decimal value ) {
 602                         return Insert (index, value.ToString());
 603                 }
 604
 605                 public StringBuilder Insert( int index, double value ) {
 606                         return Insert (index, value.ToString());
 607                 }
 608
 609                 public StringBuilder Insert( int index, short value ) {
 610                         return Insert (index, value.ToString());
 611                 }
 612
 613                 public StringBuilder Insert( int index, int value ) {
 614                         return Insert (index, value.ToString());
 615                 }
 616
 617                 public StringBuilder Insert( int index, long value ) {
 618                         return Insert (index, value.ToString());
 619                 }
 620
 621                 public StringBuilder Insert( int index, object value ) {
 622                         return Insert (index, value.ToString());
 623                 }
 624
 625                 [CLSCompliant(false)]
 626                 public StringBuilder Insert( int index, sbyte value ) {
 627                         return Insert (index, value.ToString() );
 628                 }
 629
 630                 public StringBuilder Insert (int index, float value) {
 631                         return Insert (index, value.ToString() );
 632                 }
 633
 634                 [CLSCompliant(false)]
 635                 public StringBuilder Insert (int index, ushort value) {
 636                         return Insert (index, value.ToString() );
 637                 }
 638
 639                 [CLSCompliant(false)]
 640                 public StringBuilder Insert (int index, uint value) {
 641                         return Insert ( index, value.ToString() );
 642                 }
 643
 644                 [CLSCompliant(false)]
 645                 public StringBuilder Insert (int index, ulong value) {
 646                         return Insert ( index, value.ToString() );
 647                 }
 648
 649                 public StringBuilder Insert (int index, string value, int count)
 650                 {
 651                         // LAMESPEC: The spec says to throw an exception if
 652                         // count < 0, while MS throws even for count < 1!
 653                         if ( count < 0 )
 654                                 throw new ArgumentOutOfRangeException();
 655
 656                         if (value != null && value != String.Empty)
 657                                 for (int insertCount = 0; insertCount < count; insertCount++)
 658                                         Insert( index, value );
 659
 660                         return this;
 661                 }
 662
 663                 public StringBuilder Insert (int index, char [] value, int startIndex, int charCount)
 664                 {
 665                         if (value == null) {
 666                                 if (startIndex == 0 && charCount == 0)
 667                                         return this;
 668
 669                                 throw new ArgumentNullException ("value");
 670                         }
 671
 672                         if (charCount < 0 || startIndex < 0 || startIndex > value.Length - charCount)
 673                                 throw new ArgumentOutOfRangeException ();
 674
 675                         return Insert (index, new String (value, startIndex, charCount));
 676                 }
 677
 678                 private void InternalEnsureCapacity (int size)
 679                 {
 680                         if (size > _str.Length || (object) _cached_str == (object) _str) {
 681                                 int capacity = _str.Length;
 682
 683                                 // Try double buffer, if that doesn't work, set the length as capacity
 684                                 if (size > capacity) {
 685
 686                                         // The first time a string is appended, we just set _cached_str
 687                                         // and _str to it. This allows us to do some optimizations.
 688                                         // Below, we take this into account.
 689                                         if ((object) _cached_str == (object) _str && capacity < constDefaultCapacity)
 690                                                 capacity = constDefaultCapacity;
 691
 692                                         capacity = capacity << 1;
 693                                         if (size > capacity)
 694                                                 capacity = size;
 695
 696                                         if (capacity >= Int32.MaxValue || capacity < 0)
 697                                                 capacity = Int32.MaxValue;
 698
 699                                         if (capacity > _maxCapacity && size <= _maxCapacity)
 700                                                 capacity = _maxCapacity;
 701
 702                                         if (capacity > _maxCapacity)
 703                                                 throw new ArgumentOutOfRangeException ("size", "capacity was less than the current size.");
 704                                 }
 705
 706                                 string tmp = String.InternalAllocateStr (capacity);
 707                                 if (_length > 0)
 708                                         String.CharCopy (tmp, 0, _str, 0, _length);
 709
 710                                 _str = tmp;
 711                         }
 712
 713                         _cached_str = null;
 714                 }
 715
 716 #if NET_2_0
 717                 [ComVisible (false)]
 718                 public void CopyTo (int sourceIndex, char [] destination, int destinationIndex, int count)
 719                 {
 720                         if (destination == null)
 721                                 throw new ArgumentNullException ("destination");
 722                         if ((Length - count < sourceIndex) ||
 723                             (destination.Length -count < destinationIndex) ||
 724                             (sourceIndex < 0 || destinationIndex < 0 || count < 0))
 725                                 throw new ArgumentOutOfRangeException ();
 726
 727                         for (int i = 0; i < count; i++)
 728                                 destination [destinationIndex+i] = _str [sourceIndex+i];
 729                 }
 730
 731                 void ISerializable.GetObjectData (SerializationInfo info, StreamingContext context)
 732                 {
 733                         info.AddValue ("m_MaxCapacity", _maxCapacity);
 734                         info.AddValue ("Capacity", Capacity);
 735                         info.AddValue ("m_StringValue", ToString ());
 736                         info.AddValue ("m_currentThread", 0);
 737                 }
 738
 739                 StringBuilder (SerializationInfo info, StreamingContext context)
 740                 {
 741                         string s = info.GetString ("m_StringValue");
 742                         if (s == null)
 743                                 s = "";
 744                         _length = s.Length;
 745                         _str = _cached_str = s;
 746
 747                         _maxCapacity = info.GetInt32 ("m_MaxCapacity");
 748                         if (_maxCapacity < 0)
 749                                 _maxCapacity = Int32.MaxValue;
 750                         Capacity = info.GetInt32 ("Capacity");
 751                 }
 752 #endif
 753         }
 754 }