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.InternalStrcpy(_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                                 _cached_str = _str.Substring(0, _length);
 207                                 return _cached_str;
 208                         }
 209
 210                         _cached_str = _str;
 211                         _str.InternalSetLength(_length);
 212
 213                         return _str;
 214                 }
 215
 216                 public string ToString (int startIndex, int length)
 217                 {
 218                         // re-ordered to avoid possible integer overflow
 219                         if (startIndex < 0 || length < 0 || startIndex > _length - length)
 220                                 throw new ArgumentOutOfRangeException();
 221
 222                         return _str.Substring (startIndex, length);
 223                 }
 224
 225                 public int EnsureCapacity (int capacity)
 226                 {
 227                         if (capacity < 0)
 228                                 throw new ArgumentOutOfRangeException ("Capacity must be greater than 0." );
 229
 230                         if( capacity <= _str.Length )
 231                                 return _str.Length;
 232
 233                         InternalEnsureCapacity (capacity);
 234
 235                         return _str.Length;
 236                 }
 237
 238                 public bool Equals (StringBuilder sb)
 239                 {
 240                         if (((object)sb) == null)
 241                                 return false;
 242
 243                         if (_length == sb.Length && _str == sb._str )
 244                                 return true;
 245
 246                         return false;
 247                 }
 248
 249                 public StringBuilder Remove (int startIndex, int length)
 250                 {
 251                         // re-ordered to avoid possible integer overflow
 252                         if (startIndex < 0 || length < 0 || startIndex > _length - length)
 253                                 throw new ArgumentOutOfRangeException();
 254
 255                         if (null != _cached_str)
 256                                 InternalEnsureCapacity (_length);
 257
 258                         // Copy everything after the 'removed' part to the start
 259                         // of the removed part and truncate the sLength
 260                         if (_length - (startIndex + length) > 0)
 261                                 String.InternalStrcpy (_str, startIndex, _str, startIndex + length, _length - (startIndex + length));
 262
 263                         _length -= length;
 264
 265                         return this;
 266                 }
 267
 268                 public StringBuilder Replace (char oldChar, char newChar)
 269                 {
 270                         return Replace( oldChar, newChar, 0, _length);
 271                 }
 272
 273                 public StringBuilder Replace (char oldChar, char newChar, int startIndex, int count)
 274                 {
 275                         // re-ordered to avoid possible integer overflow
 276                         if (startIndex > _length - count || startIndex < 0 || count < 0)
 277                                 throw new ArgumentOutOfRangeException();
 278
 279                         if (null != _cached_str)
 280                                 InternalEnsureCapacity (_str.Length);
 281
 282                         for (int replaceIterate = startIndex; replaceIterate < startIndex + count; replaceIterate++ ) {
 283                                 if( _str [replaceIterate] == oldChar )
 284                                         _str.InternalSetChar (replaceIterate, newChar);
 285                         }
 286
 287                         return this;
 288                 }
 289
 290                 public StringBuilder Replace( string oldValue, string newValue ) {
 291                         return Replace (oldValue, newValue, 0, _length);
 292                 }
 293
 294                 public StringBuilder Replace( string oldValue, string newValue, int startIndex, int count )
 295                 {
 296                         if (oldValue == null)
 297                                 throw new ArgumentNullException ("The old value cannot be null.");
 298
 299                         if (startIndex < 0 || count < 0 || startIndex > _length - count)
 300                                 throw new ArgumentOutOfRangeException ();
 301
 302                         if (oldValue.Length == 0)
 303                                 throw new ArgumentException ("The old value cannot be zero length.");
 304
 305                         // TODO: OPTIMIZE!
 306                         string replace = _str.Substring(startIndex, count).Replace(oldValue, newValue);
 307
 308                         InternalEnsureCapacity (replace.Length + (_length - count));
 309
 310                         string end = _str.Substring (startIndex + count, _length - startIndex - count );
 311
 312                         String.InternalStrcpy (_str, startIndex, replace);
 313                         String.InternalStrcpy (_str, startIndex + replace.Length, end);
 314
 315                         _length = replace.Length + (_length - count);
 316
 317                         return this;
 318                 }
 319
 320
 321                 /* The Append Methods */
 322                 public StringBuilder Append (char[] value)
 323                 {
 324                         if (value == null)
 325                                 return this;
 326
 327                         int needed_cap = _length + value.Length;
 328                         if (null != _cached_str || _str.Length < needed_cap)
 329                                 InternalEnsureCapacity (needed_cap);
 330
 331                         String.InternalStrcpy (_str, _length, value);
 332                         _length = needed_cap;
 333
 334                         return this;
 335                 }
 336
 337                 public StringBuilder Append (string value)
 338                 {
 339                         if (value == null)
 340                                 return this;
 341
 342                         if (_length == 0 && value.Length < _maxCapacity && value.Length > _str.Length) {
 343                                 _length = value.Length;
 344                                 _str = _cached_str = value;
 345                                 return this;
 346                         }
 347
 348                         int needed_cap = _length + value.Length;
 349                         if (null != _cached_str || _str.Length < needed_cap)
 350                                 InternalEnsureCapacity (needed_cap);
 351
 352                         String.InternalStrcpy (_str, _length, value);
 353                         _length = needed_cap;
 354                         return this;
 355                 }
 356
 357                 public StringBuilder Append (bool value) {
 358                         return Append (value.ToString());
 359                 }
 360
 361                 public StringBuilder Append (byte value) {
 362                         return Append (value.ToString());
 363                 }
 364
 365                 public StringBuilder Append (decimal value) {
 366                         return Append (value.ToString());
 367                 }
 368
 369                 public StringBuilder Append (double value) {
 370                         return Append (value.ToString());
 371                 }
 372
 373                 public StringBuilder Append (short value) {
 374                         return Append (value.ToString());
 375                 }
 376
 377                 public StringBuilder Append (int value) {
 378                         return Append (value.ToString());
 379                 }
 380
 381                 public StringBuilder Append (long value) {
 382                         return Append (value.ToString());
 383                 }
 384
 385                 public StringBuilder Append (object value) {
 386                         if (value == null)
 387                                 return this;
 388
 389                         return Append (value.ToString());
 390                 }
 391
 392                 [CLSCompliant(false)]
 393                 public StringBuilder Append (sbyte value) {
 394                         return Append (value.ToString());
 395                 }
 396
 397                 public StringBuilder Append (float value) {
 398                         return Append (value.ToString());
 399                 }
 400
 401                 [CLSCompliant(false)]
 402                 public StringBuilder Append (ushort value) {
 403                         return Append (value.ToString());
 404                 }
 405
 406                 [CLSCompliant(false)]
 407                 public StringBuilder Append (uint value) {
 408                         return Append (value.ToString());
 409                 }
 410
 411                 [CLSCompliant(false)]
 412                 public StringBuilder Append (ulong value) {
 413                         return Append (value.ToString());
 414                 }
 415
 416                 public StringBuilder Append (char value)
 417                 {
 418                         int needed_cap = _length + 1;
 419                         if (null != _cached_str || _str.Length < needed_cap)
 420                                 InternalEnsureCapacity (needed_cap);
 421
 422                         _str.InternalSetChar(_length, value);
 423                         _length = needed_cap;
 424
 425                         return this;
 426                 }
 427
 428                 public StringBuilder Append (char value, int repeatCount)
 429                 {
 430                         if( repeatCount < 0 )
 431                                 throw new ArgumentOutOfRangeException();
 432
 433                         InternalEnsureCapacity (_length + repeatCount);
 434
 435                         for (int i = 0; i < repeatCount; i++)
 436                                 _str.InternalSetChar (_length++, value);
 437
 438                         return this;
 439                 }
 440
 441                 public StringBuilder Append( char[] value, int startIndex, int charCount )
 442                 {
 443                         if (value == null) {
 444                                 if (!(startIndex == 0 && charCount == 0))
 445                                         throw new ArgumentNullException ("value");
 446
 447                                 return this;
 448                         }
 449
 450                         if ((charCount < 0 || startIndex < 0) || (startIndex > value.Length - charCount))
 451                                 throw new ArgumentOutOfRangeException();
 452
 453                         int needed_cap = _length + charCount;
 454                         InternalEnsureCapacity (needed_cap);
 455
 456                         String.InternalStrcpy (_str, _length, value, startIndex, charCount);
 457                         _length = needed_cap;
 458
 459                         return this;
 460                 }
 461
 462                 public StringBuilder Append (string value, int startIndex, int count)
 463                 {
 464                         if (value == null) {
 465                                 if (startIndex != 0 && count != 0)
 466                                         throw new ArgumentNullException ("value");
 467
 468                                 return this;
 469                         }
 470
 471                         if ((count < 0 || startIndex < 0) || (startIndex > value.Length - count))
 472                                 throw new ArgumentOutOfRangeException();
 473
 474                         int needed_cap = _length + count;
 475                         if (null != _cached_str || _str.Length < needed_cap)
 476                                 InternalEnsureCapacity (needed_cap);
 477
 478                         String.InternalStrcpy (_str, _length, value, startIndex, count);
 479
 480                         _length = needed_cap;
 481
 482                         return this;
 483                 }
 484
 485 #if NET_2_0
 486                 [ComVisible (false)]
 487                 public StringBuilder AppendLine ()
 488                 {
 489                         return Append (System.Environment.NewLine);
 490                 }
 491
 492                 [ComVisible (false)]
 493                 public StringBuilder AppendLine (string value)
 494                 {
 495                         return Append (value).Append (System.Environment.NewLine);
 496                 }
 497 #endif
 498
 499                 public StringBuilder AppendFormat (string format, object arg0)
 500                 {
 501                         return AppendFormat (null, format, new object [] { arg0 });
 502                 }
 503
 504                 public StringBuilder AppendFormat (string format, params object[] args)
 505                 {
 506                         return AppendFormat (null, format, args);
 507                 }
 508
 509                 public StringBuilder AppendFormat (IFormatProvider provider,
 510                                                    string format,
 511                                                    params object[] args)
 512                 {
 513                         String.FormatHelper (this, provider, format, args);
 514                         return this;
 515                 }
 516
 517                 public StringBuilder AppendFormat (string format, object arg0, object arg1)
 518                 {
 519                         return AppendFormat (null, format, new object [] { arg0, arg1 });
 520                 }
 521
 522                 public StringBuilder AppendFormat (string format, object arg0, object arg1, object arg2)
 523                 {
 524                         return AppendFormat (null, format, new object [] { arg0, arg1, arg2 });
 525                 }
 526
 527                 /*  The Insert Functions */
 528
 529                 public StringBuilder Insert (int index, char[] value)
 530                 {
 531                         return Insert (index, new string (value));
 532                 }
 533
 534                 public StringBuilder Insert (int index, string value)
 535                 {
 536                         if( index > _length || index < 0)
 537                                 throw new ArgumentOutOfRangeException();
 538
 539                         if (value == null || value.Length == 0)
 540                                 return this;
 541
 542                         InternalEnsureCapacity (_length + value.Length);
 543
 544                         // Move everything to the right of the insert point across
 545                         String.InternalStrcpy (_str, index + value.Length, _str, index, _length - index);
 546
 547                         // Copy in stuff from the insert buffer
 548                         String.InternalStrcpy (_str, index, value);
 549
 550                         _length += value.Length;
 551
 552                         return this;
 553                 }
 554
 555                 public StringBuilder Insert( int index, bool value ) {
 556                         return Insert (index, value.ToString());
 557                 }
 558
 559                 public StringBuilder Insert( int index, byte value ) {
 560                         return Insert (index, value.ToString());
 561                 }
 562
 563                 public StringBuilder Insert( int index, char value)
 564                 {
 565                         if (index > _length || index < 0)
 566                                 throw new ArgumentOutOfRangeException ("index");
 567
 568                         InternalEnsureCapacity (_length + 1);
 569
 570                         // Move everything to the right of the insert point across
 571                         String.InternalStrcpy (_str, index + 1, _str, index, _length - index);
 572
 573                         _str.InternalSetChar (index, value);
 574                         _length++;
 575
 576                         return this;
 577                 }
 578
 579                 public StringBuilder Insert( int index, decimal value ) {
 580                         return Insert (index, value.ToString());
 581                 }
 582
 583                 public StringBuilder Insert( int index, double value ) {
 584                         return Insert (index, value.ToString());
 585                 }
 586
 587                 public StringBuilder Insert( int index, short value ) {
 588                         return Insert (index, value.ToString());
 589                 }
 590
 591                 public StringBuilder Insert( int index, int value ) {
 592                         return Insert (index, value.ToString());
 593                 }
 594
 595                 public StringBuilder Insert( int index, long value ) {
 596                         return Insert (index, value.ToString());
 597                 }
 598
 599                 public StringBuilder Insert( int index, object value ) {
 600                         return Insert (index, value.ToString());
 601                 }
 602
 603                 [CLSCompliant(false)]
 604                 public StringBuilder Insert( int index, sbyte value ) {
 605                         return Insert (index, value.ToString() );
 606                 }
 607
 608                 public StringBuilder Insert (int index, float value) {
 609                         return Insert (index, value.ToString() );
 610                 }
 611
 612                 [CLSCompliant(false)]
 613                 public StringBuilder Insert (int index, ushort value) {
 614                         return Insert (index, value.ToString() );
 615                 }
 616
 617                 [CLSCompliant(false)]
 618                 public StringBuilder Insert (int index, uint value) {
 619                         return Insert ( index, value.ToString() );
 620                 }
 621
 622                 [CLSCompliant(false)]
 623                 public StringBuilder Insert (int index, ulong value) {
 624                         return Insert ( index, value.ToString() );
 625                 }
 626
 627                 public StringBuilder Insert (int index, string value, int count)
 628                 {
 629                         // LAMESPEC: The spec says to throw an exception if
 630                         // count < 0, while MS throws even for count < 1!
 631                         if ( count < 0 )
 632                                 throw new ArgumentOutOfRangeException();
 633
 634                         if (value != null && value != String.Empty)
 635                                 for (int insertCount = 0; insertCount < count; insertCount++)
 636                                         Insert( index, value );
 637
 638                         return this;
 639                 }
 640
 641                 public StringBuilder Insert (int index, char [] value, int startIndex, int charCount)
 642                 {
 643                         if (value == null) {
 644                                 if (startIndex == 0 && charCount == 0)
 645                                         return this;
 646
 647                                 throw new ArgumentNullException ("value");
 648                         }
 649
 650                         if (charCount < 0 || startIndex < 0 || startIndex > value.Length - charCount)
 651                                 throw new ArgumentOutOfRangeException ();
 652
 653                         return Insert (index, new String (value, startIndex, charCount));
 654                 }
 655
 656                 private void InternalEnsureCapacity (int size)
 657                 {
 658                         if (size > _str.Length || (object) _cached_str == (object) _str) {
 659                                 int capacity = _str.Length;
 660
 661                                 // Try double buffer, if that doesn't work, set the length as capacity
 662                                 if (size > capacity) {
 663
 664                                         // The first time a string is appended, we just set _cached_str
 665                                         // and _str to it. This allows us to do some optimizations.
 666                                         // Below, we take this into account.
 667                                         if ((object) _cached_str == (object) _str && capacity < constDefaultCapacity)
 668                                                 capacity = constDefaultCapacity;
 669
 670                                         capacity = capacity << 1;
 671                                         if (size > capacity)
 672                                                 capacity = size;
 673
 674                                         if (capacity >= Int32.MaxValue || capacity < 0)
 675                                                 capacity = Int32.MaxValue;
 676
 677                                         if (capacity > _maxCapacity && size <= _maxCapacity)
 678                                                 capacity = _maxCapacity;
 679
 680                                         if (capacity > _maxCapacity)
 681                                                 throw new ArgumentOutOfRangeException ("size", "capacity was less than the current size.");
 682                                 }
 683
 684                                 string tmp = String.InternalAllocateStr (capacity);
 685                                 if (_length > 0)
 686                                         String.InternalStrcpy (tmp, 0, _str, 0, _length);
 687
 688                                 _str = tmp;
 689                         }
 690
 691                         _cached_str = null;
 692                 }
 693
 694 #if NET_2_0
 695                 [ComVisible (false)]
 696                 public void CopyTo (int sourceIndex, char [] destination, int destinationIndex, int count)
 697                 {
 698                         if (destination == null)
 699                                 throw new ArgumentNullException ("destination");
 700                         if ((Length - count < sourceIndex) ||
 701                             (destination.Length -count < destinationIndex) ||
 702                             (sourceIndex < 0 || destinationIndex < 0 || count < 0))
 703                                 throw new ArgumentOutOfRangeException ();
 704
 705                         for (int i = 0; i < count; i++)
 706                                 destination [destinationIndex+i] = _str [sourceIndex+i];
 707                 }
 708
 709                 void ISerializable.GetObjectData (SerializationInfo info, StreamingContext context)
 710                 {
 711                         info.AddValue ("m_MaxCapacity", _maxCapacity);
 712                         info.AddValue ("Capacity", Capacity);
 713                         info.AddValue ("m_StringValue", ToString ());
 714                         info.AddValue ("m_currentThread", 0);
 715                 }
 716
 717                 StringBuilder (SerializationInfo info, StreamingContext context)
 718                 {
 719                         string s = info.GetString ("m_StringValue");
 720                         if (s == null)
 721                                 s = "";
 722                         _length = s.Length;
 723                         _str = _cached_str = s;
 724
 725                         _maxCapacity = info.GetInt32 ("m_MaxCapacity");
 726                         if (_maxCapacity < 0)
 727                                 _maxCapacity = Int32.MaxValue;
 728                         Capacity = info.GetInt32 ("Capacity");
 729                 }
 730 #endif
 731         }
 732 }