mcs/class/Managed.Windows.Forms/System.Windows.Forms/TextControl.cs

   1 // Permission is hereby granted, free of charge, to any person obtaining
   2 // a copy of this software and associated documentation files (the
   3 // "Software"), to deal in the Software without restriction, including
   4 // without limitation the rights to use, copy, modify, merge, publish,
   5 // distribute, sublicense, and/or sell copies of the Software, and to
   6 // permit persons to whom the Software is furnished to do so, subject to
   7 // the following conditions:
   8 //
   9 // The above copyright notice and this permission notice shall be
  10 // included in all copies or substantial portions of the Software.
  11 //
  12 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  13 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  14 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  15 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  16 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  17 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  18 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  19 //
  20 // Copyright (c) 2004-2006 Novell, Inc. (http://www.novell.com)
  21 //
  22 // Authors:
  23 //      Peter Bartok    pbartok@novell.com
  24 //
  25 //
  26
  27 // NOT COMPLETE
  28
  29 // There's still plenty of things missing, I've got most of it planned, just hadn't had
  30 // the time to write it all yet.
  31 // Stuff missing (in no particular order):
  32 // - Align text after RecalculateLine
  33 // - Implement tag types for hotlinks, etc.
  34 // - Implement CaretPgUp/PgDown
  35
  36 // NOTE:
  37 // selection_start.pos and selection_end.pos are 0-based
  38 // selection_start.pos = first selected char
  39 // selection_end.pos = first NOT-selected char
  40 //
  41 // FormatText methods are 1-based (as are all tags, LineTag.Start is 1 for
  42 // the first character on a line; the reason is that 0 is the position
  43 // *before* the first character on a line
  44
  45
  46 #undef Debug
  47
  48 using System;
  49 using System.Collections;
  50 using System.Drawing;
  51 using System.Drawing.Text;
  52 using System.Text;
  53 using RTF=System.Windows.Forms.RTF;
  54
  55 namespace System.Windows.Forms {
  56         internal enum LineColor {
  57                 Red     = 0,
  58                 Black   = 1
  59         }
  60
  61         internal enum CaretSelection {
  62                 Position,       // Selection=Caret
  63                 Word,           // Selection=Word under caret
  64                 Line            // Selection=Line under caret
  65         }
  66
  67         [Flags]
  68         internal enum FormatSpecified {
  69                 None,
  70
  71                 BackColor = 2,
  72                 Font = 4,
  73                 Color = 8,
  74         }
  75
  76         internal enum CaretDirection {
  77                 CharForward,    // Move a char to the right
  78                 CharBack,       // Move a char to the left
  79                 LineUp,         // Move a line up
  80                 LineDown,       // Move a line down
  81                 Home,           // Move to the beginning of the line
  82                 End,            // Move to the end of the line
  83                 PgUp,           // Move one page up
  84                 PgDn,           // Move one page down
  85                 CtrlPgUp,       // Move caret to the first visible char in the viewport
  86                 CtrlPgDn,       // Move caret to the last visible char in the viewport
  87                 CtrlHome,       // Move to the beginning of the document
  88                 CtrlEnd,        // Move to the end of the document
  89                 WordBack,       // Move to the beginning of the previous word (or beginning of line)
  90                 WordForward,    // Move to the beginning of the next word (or end of line)
  91                 SelectionStart, // Move to the beginning of the current selection
  92                 SelectionEnd,   // Move to the end of the current selection
  93                 CharForwardNoWrap,   // Move a char forward, but don't wrap onto the next line
  94                 CharBackNoWrap      // Move a char backward, but don't wrap onto the previous line
  95         }
  96
  97         internal enum LineEnding {
  98                 Wrap = 1,    // line wraps to the next line
  99                 Limp = 2,    // \r
 100                 Hard = 4,    // \r\n
 101                 Soft = 8,    // \r\r\n
 102                 Rich = 16,    // \n
 103
 104                 None = 0
 105         }
 106
 107         internal class Document : ICloneable, IEnumerable {
 108                 #region Structures
 109                 // FIXME - go through code and check for places where
 110                 // we do explicit comparisons instead of using the compare overloads
 111                 internal struct Marker {
 112                         internal Line           line;
 113                         internal LineTag        tag;
 114                         internal int            pos;
 115                         internal int            height;
 116
 117                         public static bool operator<(Marker lhs, Marker rhs) {
 118                                 if (lhs.line.line_no < rhs.line.line_no) {
 119                                         return true;
 120                                 }
 121
 122                                 if (lhs.line.line_no == rhs.line.line_no) {
 123                                         if (lhs.pos < rhs.pos) {
 124                                                 return true;
 125                                         }
 126                                 }
 127                                 return false;
 128                         }
 129
 130                         public static bool operator>(Marker lhs, Marker rhs) {
 131                                 if (lhs.line.line_no > rhs.line.line_no) {
 132                                         return true;
 133                                 }
 134
 135                                 if (lhs.line.line_no == rhs.line.line_no) {
 136                                         if (lhs.pos > rhs.pos) {
 137                                                 return true;
 138                                         }
 139                                 }
 140                                 return false;
 141                         }
 142
 143                         public static bool operator==(Marker lhs, Marker rhs) {
 144                                 if ((lhs.line.line_no == rhs.line.line_no) && (lhs.pos == rhs.pos)) {
 145                                         return true;
 146                                 }
 147                                 return false;
 148                         }
 149
 150                         public static bool operator!=(Marker lhs, Marker rhs) {
 151                                 if ((lhs.line.line_no != rhs.line.line_no) || (lhs.pos != rhs.pos)) {
 152                                         return true;
 153                                 }
 154                                 return false;
 155                         }
 156
 157                         public void Combine(Line move_to_line, int move_to_line_length) {
 158                                 line = move_to_line;
 159                                 pos += move_to_line_length;
 160                                 tag = LineTag.FindTag(line, pos);
 161                         }
 162
 163                         // This is for future use, right now Document.Split does it by hand, with some added shortcut logic
 164                         public void Split(Line move_to_line, int split_at) {
 165                                 line = move_to_line;
 166                                 pos -= split_at;
 167                                 tag = LineTag.FindTag(line, pos);
 168                         }
 169
 170                         public override bool Equals(object obj) {
 171                                    return this==(Marker)obj;
 172                         }
 173
 174                         public override int GetHashCode() {
 175                                 return base.GetHashCode ();
 176                         }
 177
 178                         public override string ToString() {
 179                                 return "Marker Line " + line + ", Position " + pos;
 180                         }
 181
 182                 }
 183                 #endregion Structures
 184
 185                 #region Local Variables
 186                 private Line            document;
 187                 private int             lines;
 188                 private Line            sentinel;
 189                 private int             document_id;
 190                 private Random          random = new Random();
 191                 internal string         password_char;
 192                 private StringBuilder   password_cache;
 193                 private bool            calc_pass;
 194                 private int             char_count;
 195                 private bool            enable_links;
 196
 197                 // For calculating widths/heights
 198                 public static readonly StringFormat string_format = new StringFormat (StringFormat.GenericTypographic);
 199
 200                 private int             recalc_suspended;
 201                 private bool            recalc_pending;
 202                 private int             recalc_start = 1;   // This starts at one, since lines are 1 based
 203                 private int             recalc_end;
 204                 private bool            recalc_optimize;
 205
 206                 private int             update_suspended;
 207                 private bool update_pending;
 208                 private int update_start = 1;
 209
 210                 internal bool           multiline;
 211                 internal HorizontalAlignment alignment;
 212                 internal bool           wrap;
 213
 214                 internal UndoManager    undo;
 215
 216                 internal Marker         caret;
 217                 internal Marker         selection_start;
 218                 internal Marker         selection_end;
 219                 internal bool           selection_visible;
 220                 internal Marker         selection_anchor;
 221                 internal Marker         selection_prev;
 222                 internal bool           selection_end_anchor;
 223
 224                 internal int            viewport_x;
 225                 internal int            viewport_y;             // The visible area of the document
 226                 internal int            offset_x;
 227                 internal int            offset_y;
 228                 internal int            viewport_width;
 229                 internal int            viewport_height;
 230
 231                 internal int            document_x;             // Width of the document
 232                 internal int            document_y;             // Height of the document
 233
 234                 internal int            crlf_size;              // 1 or 2, depending on whether we use \r\n or just \n
 235
 236                 internal TextBoxBase    owner;                  // Who's owning us?
 237                 static internal int     caret_width = 1;
 238                 static internal int     caret_shift = 1;
 239
 240                 internal int left_margin = 2;  // A left margin for all lines
 241                 internal int top_margin = 2;
 242                 internal int right_margin = 2;
 243                 #endregion      // Local Variables
 244
 245                 #region Constructors
 246                 internal Document (TextBoxBase owner)
 247                 {
 248                         lines = 0;
 249
 250                         this.owner = owner;
 251
 252                         multiline = true;
 253                         password_char = "";
 254                         calc_pass = false;
 255                         recalc_pending = false;
 256
 257                         // Tree related stuff
 258                         sentinel = new Line (this, LineEnding.None);
 259                         sentinel.color = LineColor.Black;
 260
 261                         document = sentinel;
 262
 263                         // We always have a blank line
 264                         owner.HandleCreated += new EventHandler(owner_HandleCreated);
 265                         owner.VisibleChanged += new EventHandler(owner_VisibleChanged);
 266
 267                         Add (1, String.Empty, owner.Font, owner.ForeColor, LineEnding.None);
 268
 269                         undo = new UndoManager (this);
 270
 271                         selection_visible = false;
 272                         selection_start.line = this.document;
 273                         selection_start.pos = 0;
 274                         selection_start.tag = selection_start.line.tags;
 275                         selection_end.line = this.document;
 276                         selection_end.pos = 0;
 277                         selection_end.tag = selection_end.line.tags;
 278                         selection_anchor.line = this.document;
 279                         selection_anchor.pos = 0;
 280                         selection_anchor.tag = selection_anchor.line.tags;
 281                         caret.line = this.document;
 282                         caret.pos = 0;
 283                         caret.tag = caret.line.tags;
 284
 285                         viewport_x = 0;
 286                         viewport_y = 0;
 287
 288                         offset_x = 0;
 289                         offset_y = 0;
 290
 291                         crlf_size = 2;
 292
 293                         // Default selection is empty
 294
 295                         document_id = random.Next();
 296
 297                         string_format.Trimming = StringTrimming.None;
 298                         string_format.FormatFlags = StringFormatFlags.DisplayFormatControl;
 299
 300                         UpdateMargins ();
 301                 }
 302                 #endregion
 303
 304                 #region Internal Properties
 305                 internal Line Root {
 306                         get {
 307                                 return document;
 308                         }
 309
 310                         set {
 311                                 document = value;
 312                         }
 313                 }
 314
 315                 // UIA: Method used via reflection in TextRangeProvider
 316                 internal int Lines {
 317                         get {
 318                                 return lines;
 319                         }
 320                 }
 321
 322                 internal Line CaretLine {
 323                         get {
 324                                 return caret.line;
 325                         }
 326                 }
 327
 328                 internal int CaretPosition {
 329                         get {
 330                                 return caret.pos;
 331                         }
 332                 }
 333
 334                 internal Point Caret {
 335                         get {
 336                                 return new Point((int)caret.tag.Line.widths[caret.pos] + caret.line.X, caret.line.Y);
 337                         }
 338                 }
 339
 340                 internal LineTag CaretTag {
 341                         get {
 342                                 return caret.tag;
 343                         }
 344
 345                         set {
 346                                 caret.tag = value;
 347                         }
 348                 }
 349
 350                 internal int CRLFSize {
 351                         get {
 352                                 return crlf_size;
 353                         }
 354
 355                         set {
 356                                 crlf_size = value;
 357                         }
 358                 }
 359
 360                 /// <summary>
 361                 ///  Whether text is scanned for links
 362                 /// </summary>
 363                 internal bool EnableLinks {
 364                         get { return enable_links; }
 365                         set { enable_links = value; }
 366                 }
 367
 368                 internal string PasswordChar {
 369                         get {
 370                                 return password_char;
 371                         }
 372
 373                         set {
 374                                 password_char = value;
 375                                 PasswordCache.Length = 0;
 376                                 if ((password_char.Length != 0) && (password_char[0] != '\0')) {
 377                                         calc_pass = true;
 378                                 } else {
 379                                         calc_pass = false;
 380                                 }
 381                         }
 382                 }
 383
 384                 private StringBuilder PasswordCache {
 385                         get {
 386                                 if (password_cache == null)
 387                                           password_cache = new StringBuilder();
 388                                 return password_cache;
 389                         }
 390                 }
 391
 392                 internal int ViewPortX {
 393                         get {
 394                                 return viewport_x;
 395                         }
 396
 397                         set {
 398                                 viewport_x = value;
 399                         }
 400                 }
 401
 402                 internal int Length {
 403                         get {
 404                                 return char_count + lines - 1;  // Add \n for each line but the last
 405                         }
 406                 }
 407
 408                 private int CharCount {
 409                         get {
 410                                 return char_count;
 411                         }
 412
 413                         set {
 414                                 char_count = value;
 415
 416                                 if (LengthChanged != null) {
 417                                         LengthChanged(this, EventArgs.Empty);
 418                                 }
 419                         }
 420                 }
 421
 422                 internal int ViewPortY {
 423                         get {
 424                                 return viewport_y;
 425                         }
 426
 427                         set {
 428                                 viewport_y = value;
 429                         }
 430                 }
 431
 432                 internal int OffsetX
 433                 {
 434                         get
 435                         {
 436                                 return offset_x;
 437                         }
 438
 439                         set
 440                         {
 441                                 offset_x = value;
 442                         }
 443                 }
 444
 445                 internal int OffsetY
 446                 {
 447                         get
 448                         {
 449                                 return offset_y;
 450                         }
 451
 452                         set
 453                         {
 454                                 offset_y = value;
 455                         }
 456                 }
 457
 458                 internal int ViewPortWidth {
 459                         get {
 460                                 return viewport_width;
 461                         }
 462
 463                         set {
 464                                 viewport_width = value;
 465                         }
 466                 }
 467
 468                 internal int ViewPortHeight {
 469                         get {
 470                                 return viewport_height;
 471                         }
 472
 473                         set {
 474                                 viewport_height = value;
 475                         }
 476                 }
 477
 478
 479                 internal int Width {
 480                         get {
 481                                 return this.document_x;
 482                         }
 483                 }
 484
 485                 internal int Height {
 486                         get {
 487                                 return this.document_y;
 488                         }
 489                 }
 490
 491                 internal bool SelectionVisible {
 492                         get {
 493                                 return selection_visible;
 494                         }
 495                 }
 496
 497                 internal bool Wrap {
 498                         get {
 499                                 return wrap;
 500                         }
 501
 502                         set {
 503                                 wrap = value;
 504                         }
 505                 }
 506
 507                 #endregion      // Internal Properties
 508
 509                 #region Private Methods
 510
 511                 internal void UpdateMargins ()
 512                 {
 513                         switch (owner.actual_border_style) {
 514                                 case BorderStyle.None:
 515                                         left_margin = 0;
 516                                         top_margin = 0;
 517                                         right_margin = 1;
 518                                         break;
 519                                 case BorderStyle.FixedSingle:
 520                                         left_margin = 2;
 521                                         top_margin = 2;
 522                                         right_margin = 3;
 523                                         break;
 524                                 case BorderStyle.Fixed3D:
 525                                         left_margin = 1;
 526                                         top_margin = 1;
 527                                         right_margin = 2;
 528                                         break;
 529                         }
 530                 }
 531
 532                 internal void SuspendRecalc ()
 533                 {
 534                         if (recalc_suspended == 0) {
 535                                 recalc_start = int.MaxValue;
 536                                 recalc_end = int.MinValue;
 537                         }
 538
 539                         recalc_suspended++;
 540                 }
 541
 542                 internal void ResumeRecalc (bool immediate_update)
 543                 {
 544                         if (recalc_suspended > 0)
 545                                 recalc_suspended--;
 546
 547                         if (recalc_suspended == 0 && (immediate_update || recalc_pending) && !(recalc_start == int.MaxValue && recalc_end == int.MinValue)) {
 548                                 RecalculateDocument (owner.CreateGraphicsInternal (), recalc_start, recalc_end, recalc_optimize);
 549                                 recalc_pending = false;
 550                         }
 551                 }
 552
 553                 internal void SuspendUpdate ()
 554                 {
 555                         update_suspended++;
 556                 }
 557
 558                 internal void ResumeUpdate (bool immediate_update)
 559                 {
 560                         if (update_suspended > 0)
 561                                 update_suspended--;
 562
 563                         if (immediate_update && update_suspended == 0 && update_pending) {
 564                                 UpdateView (GetLine (update_start), 0);
 565                                 update_pending = false;
 566                         }
 567                 }
 568
 569                 // For debugging
 570                 internal int DumpTree(Line line, bool with_tags) {
 571                         int     total;
 572
 573                         total = 1;
 574
 575                         Console.Write("Line {0} [# {1}], Y: {2}, ending style: {3},  Text: '{4}'",
 576                                         line.line_no, line.GetHashCode(), line.Y, line.ending,
 577                                         line.text != null ? line.text.ToString() : "undefined");
 578
 579                         if (line.left == sentinel) {
 580                                 Console.Write(", left = sentinel");
 581                         } else if (line.left == null) {
 582                                 Console.Write(", left = NULL");
 583                         }
 584
 585                         if (line.right == sentinel) {
 586                                 Console.Write(", right = sentinel");
 587                         } else if (line.right == null) {
 588                                 Console.Write(", right = NULL");
 589                         }
 590
 591                         Console.WriteLine("");
 592
 593                         if (with_tags) {
 594                                 LineTag tag;
 595                                 int     count;
 596                                 int     length;
 597
 598                                 tag = line.tags;
 599                                 count = 1;
 600                                 length = 0;
 601                                 Console.Write("   Tags: ");
 602                                 while (tag != null) {
 603                                         Console.Write("{0} <{1}>-<{2}>", count++, tag.Start, tag.End
 604                                                         /*line.text.ToString (tag.start - 1, tag.length)*/);
 605                                         length += tag.Length;
 606
 607                                         if (tag.Line != line) {
 608                                                 Console.Write("BAD line link");
 609                                                 throw new Exception("Bad line link in tree");
 610                                         }
 611                                         tag = tag.Next;
 612                                         if (tag != null) {
 613                                                 Console.Write(", ");
 614                                         }
 615                                 }
 616                                 if (length > line.text.Length) {
 617                                         throw new Exception(String.Format("Length of tags more than length of text on line (expected {0} calculated {1})", line.text.Length, length));
 618                                 } else if (length < line.text.Length) {
 619                                         throw new Exception(String.Format("Length of tags less than length of text on line (expected {0} calculated {1})", line.text.Length, length));
 620                                 }
 621                                 Console.WriteLine("");
 622                         }
 623                         if (line.left != null) {
 624                                 if (line.left != sentinel) {
 625                                         total += DumpTree(line.left, with_tags);
 626                                 }
 627                         } else {
 628                                 if (line != sentinel) {
 629                                         throw new Exception("Left should not be NULL");
 630                                 }
 631                         }
 632
 633                         if (line.right != null) {
 634                                 if (line.right != sentinel) {
 635                                         total += DumpTree(line.right, with_tags);
 636                                 }
 637                         } else {
 638                                 if (line != sentinel) {
 639                                         throw new Exception("Right should not be NULL");
 640                                 }
 641                         }
 642
 643                         for (int i = 1; i <= this.lines; i++) {
 644                                 if (GetLine(i) == null) {
 645                                         throw new Exception(String.Format("Hole in line order, missing {0}", i));
 646                                 }
 647                         }
 648
 649                         if (line == this.Root) {
 650                                 if (total < this.lines) {
 651                                         throw new Exception(String.Format("Not enough nodes in tree, found {0}, expected {1}", total, this.lines));
 652                                 } else if (total > this.lines) {
 653                                         throw new Exception(String.Format("Too many nodes in tree, found {0}, expected {1}", total, this.lines));
 654                                 }
 655                         }
 656
 657                         return total;
 658                 }
 659
 660                 private void SetSelectionVisible (bool value)
 661                 {
 662                         bool old_selection_visible = selection_visible;
 663                         selection_visible = value;
 664
 665                         // cursor and selection are enemies, we can't have both in the same room at the same time
 666                         if (owner.IsHandleCreated && !owner.show_caret_w_selection)
 667                                 XplatUI.CaretVisible (owner.Handle, !selection_visible);
 668                         if (UIASelectionChanged != null && (selection_visible || old_selection_visible))
 669                                 UIASelectionChanged (this, EventArgs.Empty);
 670                 }
 671
 672                 private void DecrementLines(int line_no) {
 673                         int     current;
 674
 675                         current = line_no;
 676                         while (current <= lines) {
 677                                 GetLine(current).line_no--;
 678                                 current++;
 679                         }
 680                         return;
 681                 }
 682
 683                 private void IncrementLines(int line_no) {
 684                         int     current;
 685
 686                         current = this.lines;
 687                         while (current >= line_no) {
 688                                 GetLine(current).line_no++;
 689                                 current--;
 690                         }
 691                         return;
 692                 }
 693
 694                 private void RebalanceAfterAdd(Line line1) {
 695                         Line    line2;
 696
 697                         while ((line1 != document) && (line1.parent.color == LineColor.Red)) {
 698                                 if (line1.parent == line1.parent.parent.left) {
 699                                         line2 = line1.parent.parent.right;
 700
 701                                         if ((line2 != null) && (line2.color == LineColor.Red)) {
 702                                                 line1.parent.color = LineColor.Black;
 703                                                 line2.color = LineColor.Black;
 704                                                 line1.parent.parent.color = LineColor.Red;
 705                                                 line1 = line1.parent.parent;
 706                                         } else {
 707                                                 if (line1 == line1.parent.right) {
 708                                                         line1 = line1.parent;
 709                                                         RotateLeft(line1);
 710                                                 }
 711
 712                                                 line1.parent.color = LineColor.Black;
 713                                                 line1.parent.parent.color = LineColor.Red;
 714
 715                                                 RotateRight(line1.parent.parent);
 716                                         }
 717                                 } else {
 718                                         line2 = line1.parent.parent.left;
 719
 720                                         if ((line2 != null) && (line2.color == LineColor.Red)) {
 721                                                 line1.parent.color = LineColor.Black;
 722                                                 line2.color = LineColor.Black;
 723                                                 line1.parent.parent.color = LineColor.Red;
 724                                                 line1 = line1.parent.parent;
 725                                         } else {
 726                                                 if (line1 == line1.parent.left) {
 727                                                         line1 = line1.parent;
 728                                                         RotateRight(line1);
 729                                                 }
 730
 731                                                 line1.parent.color = LineColor.Black;
 732                                                 line1.parent.parent.color = LineColor.Red;
 733                                                 RotateLeft(line1.parent.parent);
 734                                         }
 735                                 }
 736                         }
 737                         document.color = LineColor.Black;
 738                 }
 739
 740                 private void RebalanceAfterDelete(Line line1) {
 741                         Line line2;
 742
 743                         while ((line1 != document) && (line1.color == LineColor.Black)) {
 744                                 if (line1 == line1.parent.left) {
 745                                         line2 = line1.parent.right;
 746                                         if (line2.color == LineColor.Red) {
 747                                                 line2.color = LineColor.Black;
 748                                                 line1.parent.color = LineColor.Red;
 749                                                 RotateLeft(line1.parent);
 750                                                 line2 = line1.parent.right;
 751                                         }
 752                                         if ((line2.left.color == LineColor.Black) && (line2.right.color == LineColor.Black)) {
 753                                                 line2.color = LineColor.Red;
 754                                                 line1 = line1.parent;
 755                                         } else {
 756                                                 if (line2.right.color == LineColor.Black) {
 757                                                         line2.left.color = LineColor.Black;
 758                                                         line2.color = LineColor.Red;
 759                                                         RotateRight(line2);
 760                                                         line2 = line1.parent.right;
 761                                                 }
 762                                                 line2.color = line1.parent.color;
 763                                                 line1.parent.color = LineColor.Black;
 764                                                 line2.right.color = LineColor.Black;
 765                                                 RotateLeft(line1.parent);
 766                                                 line1 = document;
 767                                         }
 768                                 } else {
 769                                         line2 = line1.parent.left;
 770                                         if (line2.color == LineColor.Red) {
 771                                                 line2.color = LineColor.Black;
 772                                                 line1.parent.color = LineColor.Red;
 773                                                 RotateRight(line1.parent);
 774                                                 line2 = line1.parent.left;
 775                                         }
 776                                         if ((line2.right.color == LineColor.Black) && (line2.left.color == LineColor.Black)) {
 777                                                 line2.color = LineColor.Red;
 778                                                 line1 = line1.parent;
 779                                         } else {
 780                                                 if (line2.left.color == LineColor.Black) {
 781                                                         line2.right.color = LineColor.Black;
 782                                                         line2.color = LineColor.Red;
 783                                                         RotateLeft(line2);
 784                                                         line2 = line1.parent.left;
 785                                                 }
 786                                                 line2.color = line1.parent.color;
 787                                                 line1.parent.color = LineColor.Black;
 788                                                 line2.left.color = LineColor.Black;
 789                                                 RotateRight(line1.parent);
 790                                                 line1 = document;
 791                                         }
 792                                 }
 793                         }
 794                         line1.color = LineColor.Black;
 795                 }
 796
 797                 private void RotateLeft(Line line1) {
 798                         Line    line2 = line1.right;
 799
 800                         line1.right = line2.left;
 801
 802                         if (line2.left != sentinel) {
 803                                 line2.left.parent = line1;
 804                         }
 805
 806                         if (line2 != sentinel) {
 807                                 line2.parent = line1.parent;
 808                         }
 809
 810                         if (line1.parent != null) {
 811                                 if (line1 == line1.parent.left) {
 812                                         line1.parent.left = line2;
 813                                 } else {
 814                                         line1.parent.right = line2;
 815                                 }
 816                         } else {
 817                                 document = line2;
 818                         }
 819
 820                         line2.left = line1;
 821                         if (line1 != sentinel) {
 822                                 line1.parent = line2;
 823                         }
 824                 }
 825
 826                 private void RotateRight(Line line1) {
 827                         Line line2 = line1.left;
 828
 829                         line1.left = line2.right;
 830
 831                         if (line2.right != sentinel) {
 832                                 line2.right.parent = line1;
 833                         }
 834
 835                         if (line2 != sentinel) {
 836                                 line2.parent = line1.parent;
 837                         }
 838
 839                         if (line1.parent != null) {
 840                                 if (line1 == line1.parent.right) {
 841                                         line1.parent.right = line2;
 842                                 } else {
 843                                         line1.parent.left = line2;
 844                                 }
 845                         } else {
 846                                 document = line2;
 847                         }
 848
 849                         line2.right = line1;
 850                         if (line1 != sentinel) {
 851                                 line1.parent = line2;
 852                         }
 853                 }
 854
 855
 856                 internal void UpdateView(Line line, int pos) {
 857                         if (!owner.IsHandleCreated) {
 858                                 return;
 859                         }
 860
 861                         if (update_suspended > 0) {
 862                                 update_start = Math.Min (update_start, line.line_no);
 863                                 // update_end = Math.Max (update_end, line.line_no);
 864                                 // recalc_optimize = true;
 865                                 update_pending = true;
 866                                 return;
 867                         }
 868
 869                         // Optimize invalidation based on Line alignment
 870                         if (RecalculateDocument(owner.CreateGraphicsInternal(), line.line_no, line.line_no, true)) {
 871                                 // Lineheight changed, invalidate the rest of the document
 872                                 if ((line.Y - viewport_y) >=0 ) {
 873                                         // We formatted something that's in view, only draw parts of the screen
 874                                         owner.Invalidate(new Rectangle(
 875                                                 offset_x,
 876                                                 line.Y - viewport_y + offset_y,
 877                                                 viewport_width,
 878                                                 owner.Height - (line.Y - viewport_y)));
 879                                 } else {
 880                                         // The tag was above the visible area, draw everything
 881                                         owner.Invalidate();
 882                                 }
 883                         } else {
 884                                 switch(line.alignment) {
 885                                         case HorizontalAlignment.Left: {
 886                                                 owner.Invalidate(new Rectangle(
 887                                                         line.X + ((int)line.widths[pos] - viewport_x - 1) + offset_x,
 888                                                         line.Y - viewport_y + offset_y,
 889                                                         viewport_width,
 890                                                         line.height + 1));
 891                                                 break;
 892                                         }
 893
 894                                         case HorizontalAlignment.Center: {
 895                                                 owner.Invalidate(new Rectangle(
 896                                                         line.X + offset_x,
 897                                                         line.Y - viewport_y + offset_y,
 898                                                         viewport_width,
 899                                                         line.height + 1));
 900                                                 break;
 901                                         }
 902
 903                                         case HorizontalAlignment.Right: {
 904                                                 owner.Invalidate(new Rectangle(
 905                                                         line.X + offset_x,
 906                                                         line.Y - viewport_y + offset_y,
 907                                                         (int)line.widths[pos + 1] - viewport_x + line.X,
 908                                                         line.height + 1));
 909                                                 break;
 910                                         }
 911                                 }
 912                         }
 913                 }
 914
 915
 916                 // Update display from line, down line_count lines; pos is unused, but required for the signature
 917                 internal void UpdateView(Line line, int line_count, int pos) {
 918                         if (!owner.IsHandleCreated) {
 919                                 return;
 920                         }
 921
 922                         if (recalc_suspended > 0) {
 923                                 recalc_start = Math.Min (recalc_start, line.line_no);
 924                                 recalc_end = Math.Max (recalc_end, line.line_no + line_count);
 925                                 recalc_optimize = true;
 926                                 recalc_pending = true;
 927                                 return;
 928                         }
 929
 930                         int start_line_top = line.Y;
 931
 932                         Line end_line = GetLine (line.line_no + line_count);
 933                         if (end_line == null)
 934                                 end_line = GetLine (lines);
 935
 936                         if (end_line == null)
 937                                 return;
 938
 939                         int end_line_bottom = end_line.Y + end_line.height;
 940
 941                         if (RecalculateDocument(owner.CreateGraphicsInternal(), line.line_no, line.line_no + line_count, true)) {
 942                                 // Lineheight changed, invalidate the rest of the document
 943                                 if ((line.Y - viewport_y) >=0 ) {
 944                                         // We formatted something that's in view, only draw parts of the screen
 945                                         owner.Invalidate(new Rectangle(
 946                                                 offset_x,
 947                                                 line.Y - viewport_y + offset_y,
 948                                                 viewport_width,
 949                                                 owner.Height - (line.Y - viewport_y)));
 950                                 } else {
 951                                         // The tag was above the visible area, draw everything
 952                                         owner.Invalidate();
 953                                 }
 954                         } else {
 955                                 int x = 0 - viewport_x + offset_x;
 956                                 int w = viewport_width;
 957                                 int y = Math.Min (start_line_top - viewport_y, line.Y - viewport_y) + offset_y;
 958                                 int h = Math.Max (end_line_bottom - y, end_line.Y + end_line.height - y);
 959
 960                                 owner.Invalidate (new Rectangle (x, y, w, h));
 961                         }
 962                 }
 963
 964                 /// <summary>
 965                 ///  Scans the next paragraph for http:/ ftp:/ www. https:/ etc and marks the tags
 966                 ///  as links.
 967                 /// </summary>
 968                 /// <param name="start_line">The line to start on</param>
 969                 /// <param name="link_changed">marks as true if something is changed</param>
 970                 private void ScanForLinks (Line start_line, ref bool link_changed)
 971                 {
 972                         Line current_line = start_line;
 973                         StringBuilder line_no_breaks = new StringBuilder ();
 974                         StringBuilder line_link_record = new StringBuilder ();
 975                         ArrayList cumulative_length_list = new ArrayList ();
 976                         bool update_caret_tag = false;
 977
 978                         cumulative_length_list.Add (0);
 979
 980                         while (current_line != null) {
 981                                 line_no_breaks.Append (current_line.text);
 982
 983                                 if (link_changed == false)
 984                                         current_line.LinkRecord (line_link_record);
 985
 986                                 current_line.ClearLinks ();
 987
 988                                 cumulative_length_list.Add (line_no_breaks.Length);
 989
 990                                 if (current_line.ending == LineEnding.Wrap)
 991                                         current_line = GetLine (current_line.LineNo + 1);
 992                                 else
 993                                         break;
 994                         }
 995
 996                         // search for protocols.. make sure www. is first!
 997                         string [] search_terms = new string [] { "www.", "http:/", "ftp:/", "https:/" };
 998                         int search_found = 0;
 999                         int index_found = 0;
1000                         string line_no_breaks_string = line_no_breaks.ToString ();
1001                         int line_no_breaks_index = 0;
1002                         int link_end = 0;
1003
1004                         while (true) {
1005                                 if (line_no_breaks_index >= line_no_breaks_string.Length)
1006                                         break;
1007
1008                                 index_found = FirstIndexOfAny (line_no_breaks_string, search_terms, line_no_breaks_index, out search_found);
1009
1010                                 //no links found on this line
1011                                 if (index_found == -1)
1012                                         break;
1013
1014                                 if (search_found == 0) {
1015                                         // if we are at the end of the line to analyse and the end of the line
1016                                         // is "www." then there are no links here
1017                                         if (line_no_breaks_string.Length == index_found + search_terms [0].Length)
1018                                                 break;
1019
1020                                         // if after www. we don't have a letter a digit or a @ or - or /
1021                                         // then it is not a web address, we should continue searching
1022                                         if (char.IsLetterOrDigit (line_no_breaks_string [index_found + search_terms [0].Length]) == false &&
1023                                                 "@/~".IndexOf (line_no_breaks_string [index_found + search_terms [0].Length].ToString ()) == -1) {
1024                                                 line_no_breaks_index = index_found + search_terms [0].Length;
1025                                                 continue;
1026                                         }
1027                                 }
1028
1029                                 link_end = line_no_breaks_string.Length - 1;
1030                                 line_no_breaks_index = line_no_breaks_string.Length;
1031
1032                                 // we've found a link, we just need to find where it ends now
1033                                 for (int i = index_found + search_terms [search_found].Length; i < line_no_breaks_string.Length; i++) {
1034                                         if (line_no_breaks_string [i - 1] == '.') {
1035                                                 if (char.IsLetterOrDigit (line_no_breaks_string [i]) == false &&
1036                                                         "@/~".IndexOf (line_no_breaks_string [i].ToString ()) == -1) {
1037                                                         link_end = i - 1;
1038                                                         line_no_breaks_index = i;
1039                                                         break;
1040                                                 }
1041                                         } else {
1042                                                 if (char.IsLetterOrDigit (line_no_breaks_string [i]) == false &&
1043                                                         "@-/:~.?=_&".IndexOf (line_no_breaks_string [i].ToString ()) == -1) {
1044                                                         link_end = i - 1;
1045                                                         line_no_breaks_index = i;
1046                                                         break;
1047                                                 }
1048                                         }
1049                                 }
1050
1051                                 string link_text = line_no_breaks_string.Substring (index_found, link_end - index_found + 1);
1052                                 int current_cumulative = 0;
1053
1054                                 // we've found a link - index_found -> link_end
1055                                 // now we just make all the tags as containing link and
1056                                 // point them to the text for the whole link
1057
1058                                 current_line = start_line;
1059
1060                                 //find the line we start on
1061                                 for (current_cumulative = 1; current_cumulative < cumulative_length_list.Count; current_cumulative++)
1062                                         if ((int)cumulative_length_list [current_cumulative] > index_found)
1063                                                 break;
1064
1065                                 current_line = GetLine (start_line.LineNo + current_cumulative - 1);
1066
1067                                 // find the tag we start on
1068                                 LineTag current_tag = current_line.FindTag (index_found - (int)cumulative_length_list [current_cumulative - 1] + 1);
1069
1070                                 if (current_tag.Start != (index_found - (int)cumulative_length_list [current_cumulative - 1]) + 1) {
1071                                         if (current_tag == CaretTag)
1072                                                 update_caret_tag = true;
1073
1074                                         current_tag = current_tag.Break ((index_found - (int)cumulative_length_list [current_cumulative - 1]) + 1);
1075                                 }
1076
1077                                 // set the tag
1078                                 current_tag.IsLink = true;
1079                                 current_tag.LinkText = link_text;
1080
1081                                 //go through each character
1082                                 // find the tag we are in
1083                                 // skip the number of characters in the tag
1084                                 for (int i = 1; i < link_text.Length; i++) {
1085                                         // on to a new word-wrapped line
1086                                         if ((int)cumulative_length_list [current_cumulative] <= index_found + i) {
1087
1088                                                 current_line = GetLine (start_line.LineNo + current_cumulative++);
1089                                                 current_tag = current_line.FindTag (index_found + i - (int)cumulative_length_list [current_cumulative - 1] + 1);
1090
1091                                                 current_tag.IsLink = true;
1092                                                 current_tag.LinkText = link_text;
1093
1094                                                 continue;
1095                                         }
1096
1097                                         if (current_tag.End < index_found + 1 + i - (int)cumulative_length_list [current_cumulative - 1]) {
1098                                                 // skip empty tags in the middle of the URL
1099                                                 do {
1100                                                         current_tag = current_tag.Next;
1101                                                 } while (current_tag.Length == 0);
1102
1103                                                 current_tag.IsLink = true;
1104                                                 current_tag.LinkText = link_text;
1105                                         }
1106                                 }
1107
1108                                 //if there are characters left in the tag after the link
1109                                 // split the tag
1110                                 // make the second part a non link
1111                                 if (current_tag.End > (index_found + link_text.Length + 1) - (int)cumulative_length_list [current_cumulative - 1]) {
1112                                         if (current_tag == CaretTag)
1113                                                 update_caret_tag = true;
1114
1115                                         current_tag.Break ((index_found + link_text.Length + 1) - (int)cumulative_length_list [current_cumulative - 1]);
1116                                 }
1117                         }
1118
1119                         if (update_caret_tag) {
1120                                 CaretTag = LineTag.FindTag (CaretLine, CaretPosition);
1121                                 link_changed = true;
1122                         } else {
1123                                 if (link_changed == false) {
1124                                         current_line = start_line;
1125                                         StringBuilder new_link_record = new StringBuilder ();
1126
1127                                         while (current_line != null) {
1128                                                 current_line.LinkRecord (new_link_record);
1129
1130                                                 if (current_line.ending == LineEnding.Wrap)
1131                                                         current_line = GetLine (current_line.LineNo + 1);
1132                                                 else
1133                                                         break;
1134                                         }
1135
1136                                         if (new_link_record.Equals (line_link_record) == false)
1137                                                 link_changed = true;
1138                                 }
1139                         }
1140                 }
1141
1142                 private int FirstIndexOfAny (string haystack, string [] needles, int start_index, out int term_found)
1143                 {
1144                         term_found = -1;
1145                         int best_index = -1;
1146
1147                         for (int i = 0; i < needles.Length; i++) {
1148                                 int index = haystack.IndexOf (needles [i], start_index, StringComparison.InvariantCultureIgnoreCase);
1149
1150                                 if (index > -1) {
1151                                         if (term_found > -1) {
1152                                                 if (index < best_index) {
1153                                                         best_index = index;
1154                                                         term_found = i;
1155                                                 }
1156                                         } else {
1157                                                 best_index = index;
1158                                                 term_found = i;
1159                                         }
1160                                 }
1161                         }
1162
1163                         return best_index;
1164                 }
1165
1166
1167
1168                 private void InvalidateLinks (Rectangle clip)
1169                 {
1170                         for (int i = (owner.list_links.Count - 1); i >= 0; i--) {
1171                                 TextBoxBase.LinkRectangle link = (TextBoxBase.LinkRectangle) owner.list_links [i];
1172
1173                                 if (clip.IntersectsWith (link.LinkAreaRectangle))
1174                                         owner.list_links.RemoveAt (i);
1175                         }
1176                 }
1177                 #endregion      // Private Methods
1178
1179                 #region Internal Methods
1180
1181                 internal void ScanForLinks (int start, int end, ref bool link_changed)
1182                 {
1183                         Line line = null;
1184                         LineEnding lastending = LineEnding.Rich;
1185
1186                         // make sure we start scanning at the real begining of the line
1187                         while (true) {
1188                                 if (start != 1 && GetLine (start - 1).ending == LineEnding.Wrap)
1189                                         start--;
1190                                 else
1191                                         break;
1192                         }
1193
1194                         for (int i = start; i <= end && i <= lines; i++) {
1195                                 line = GetLine (i);
1196
1197                                 if (lastending != LineEnding.Wrap)
1198                                         ScanForLinks (line, ref link_changed);
1199
1200                                 lastending = line.ending;
1201
1202                                 if (lastending == LineEnding.Wrap && (i + 1) <= end)
1203                                         end++;
1204                         }
1205                 }
1206
1207                 // Clear the document and reset state
1208                 internal void Empty() {
1209
1210                         document = sentinel;
1211                         lines = 0;
1212
1213                         // We always have a blank line
1214                         Add (1, String.Empty, owner.Font, owner.ForeColor, LineEnding.None);
1215
1216                         this.RecalculateDocument(owner.CreateGraphicsInternal());
1217                         PositionCaret(0, 0);
1218
1219                         SetSelectionVisible (false);
1220
1221                         selection_start.line = this.document;
1222                         selection_start.pos = 0;
1223                         selection_start.tag = selection_start.line.tags;
1224                         selection_end.line = this.document;
1225                         selection_end.pos = 0;
1226                         selection_end.tag = selection_end.line.tags;
1227                         char_count = 0;
1228
1229                         viewport_x = 0;
1230                         viewport_y = 0;
1231
1232                         document_x = 0;
1233                         document_y = 0;
1234
1235                         if (owner.IsHandleCreated)
1236                                 owner.Invalidate ();
1237                 }
1238
1239                 internal void PositionCaret(Line line, int pos) {
1240                         caret.tag = line.FindTag (pos);
1241
1242                         MoveCaretToTextTag ();
1243
1244                         caret.line = line;
1245                         caret.pos = pos;
1246
1247                         if (owner.IsHandleCreated) {
1248                                 if (owner.Focused) {
1249                                         if (caret.height != caret.tag.Height)
1250                                                 XplatUI.CreateCaret (owner.Handle, caret_width, caret.height);
1251                                         XplatUI.SetCaretPos(owner.Handle,
1252                                                 offset_x + (int)caret.tag.Line.widths[caret.pos] + caret.line.X - viewport_x,
1253                                                 offset_y + caret.line.Y + caret.tag.Shift - viewport_y + caret_shift);
1254                                 }
1255
1256                                 if (CaretMoved != null) CaretMoved(this, EventArgs.Empty);
1257                         }
1258
1259                         // We set this at the end because we use the heights to determine whether or
1260                         // not we need to recreate the caret
1261                         caret.height = caret.tag.Height;
1262
1263                 }
1264
1265                 internal void PositionCaret(int x, int y) {
1266                         if (!owner.IsHandleCreated) {
1267                                 return;
1268                         }
1269
1270                         caret.tag = FindCursor(x, y, out caret.pos);
1271
1272                         MoveCaretToTextTag ();
1273
1274                         caret.line = caret.tag.Line;
1275                         caret.height = caret.tag.Height;
1276
1277                         if (owner.ShowSelection && (!selection_visible || owner.show_caret_w_selection)) {
1278                                 XplatUI.CreateCaret (owner.Handle, caret_width, caret.height);
1279                                 XplatUI.SetCaretPos(owner.Handle,
1280                                         (int)caret.tag.Line.widths[caret.pos] + caret.line.X - viewport_x + offset_x,
1281                                         offset_y + caret.line.Y + caret.tag.Shift - viewport_y + caret_shift);
1282                         }
1283
1284                         if (CaretMoved != null) CaretMoved(this, EventArgs.Empty);
1285                 }
1286
1287                 internal void CaretHasFocus() {
1288                         if ((caret.tag != null) && owner.IsHandleCreated) {
1289                                 XplatUI.CreateCaret(owner.Handle, caret_width, caret.height);
1290                                 XplatUI.SetCaretPos(owner.Handle,
1291                                         offset_x + (int)caret.tag.Line.widths[caret.pos] + caret.line.X - viewport_x,
1292                                         offset_y + caret.line.Y + caret.tag.Shift - viewport_y + caret_shift);
1293
1294                                 DisplayCaret ();
1295                         }
1296
1297                         if (owner.IsHandleCreated && SelectionLength () > 0) {
1298                                 InvalidateSelectionArea ();
1299                         }
1300                 }
1301
1302                 internal void CaretLostFocus() {
1303                         if (!owner.IsHandleCreated) {
1304                                 return;
1305                         }
1306                         XplatUI.DestroyCaret(owner.Handle);
1307                 }
1308
1309                 internal void AlignCaret ()
1310                 {
1311                         AlignCaret (true);
1312                 }
1313
1314                 internal void AlignCaret(bool changeCaretTag) {
1315                         if (!owner.IsHandleCreated) {
1316                                 return;
1317                         }
1318
1319                         if (changeCaretTag) {
1320                                 caret.tag = LineTag.FindTag (caret.line, caret.pos);
1321
1322                                 MoveCaretToTextTag ();
1323                         }
1324
1325                         // if the caret has had SelectionFont changed to a
1326                         // different height, we reflect changes unless the new
1327                         // font is larger than the line (line recalculations
1328                         // ignore empty tags) in which case we make it equal
1329                         // the line height and then when text is entered
1330                         if (caret.tag.Height > caret.tag.Line.Height) {
1331                                 caret.height = caret.line.height;
1332                         } else {
1333                                 caret.height = caret.tag.Height;
1334                         }
1335
1336                         if (owner.Focused) {
1337                                 XplatUI.CreateCaret(owner.Handle, caret_width, caret.height);
1338                                 XplatUI.SetCaretPos (owner.Handle,
1339                                         offset_x + (int) caret.tag.Line.widths [caret.pos] + caret.line.X - viewport_x,
1340                                         offset_y + caret.line.Y + viewport_y + caret_shift);
1341                                 DisplayCaret ();
1342                         }
1343
1344                         if (CaretMoved != null) CaretMoved(this, EventArgs.Empty);
1345                 }
1346
1347                 internal void UpdateCaret() {
1348                         if (!owner.IsHandleCreated || caret.tag == null) {
1349                                 return;
1350                         }
1351
1352                         MoveCaretToTextTag ();
1353
1354                         if (caret.tag.Height != caret.height) {
1355                                 caret.height = caret.tag.Height;
1356                                 if (owner.Focused) {
1357                                         XplatUI.CreateCaret(owner.Handle, caret_width, caret.height);
1358                                 }
1359                         }
1360
1361                         if (owner.Focused) {
1362                                 XplatUI.SetCaretPos(owner.Handle,
1363                                         offset_x + (int)caret.tag.Line.widths[caret.pos] + caret.line.X - viewport_x,
1364                                         offset_y + caret.line.Y + caret.tag.Shift - viewport_y + caret_shift);
1365                                 DisplayCaret ();
1366                         }
1367
1368                         if (CaretMoved != null) CaretMoved(this, EventArgs.Empty);
1369                 }
1370
1371                 internal void DisplayCaret() {
1372                         if (!owner.IsHandleCreated) {
1373                                 return;
1374                         }
1375
1376                         if (owner.ShowSelection && (!selection_visible || owner.show_caret_w_selection)) {
1377                                 XplatUI.CaretVisible(owner.Handle, true);
1378                         }
1379                 }
1380
1381                 internal void HideCaret() {
1382                         if (!owner.IsHandleCreated) {
1383                                 return;
1384                         }
1385
1386                         if (owner.Focused) {
1387                                 XplatUI.CaretVisible(owner.Handle, false);
1388                         }
1389                 }
1390
1391
1392                 internal void MoveCaretToTextTag ()
1393                 {
1394                         if (caret.tag == null || caret.tag.IsTextTag)
1395                                 return;
1396
1397
1398
1399                         if (caret.pos < caret.tag.Start) {
1400                                 caret.tag = caret.tag.Previous;
1401                         } else {
1402                                 caret.tag = caret.tag.Next;
1403                         }
1404                 }
1405
1406                 internal void MoveCaret(CaretDirection direction) {
1407                         // FIXME should we use IsWordSeparator to detect whitespace, instead
1408                         // of looking for actual spaces in the Word move cases?
1409
1410                         bool nowrap = false;
1411                         switch(direction) {
1412                                 case CaretDirection.CharForwardNoWrap:
1413                                         nowrap = true;
1414                                         goto case CaretDirection.CharForward;
1415                                 case CaretDirection.CharForward: {
1416                                         caret.pos++;
1417                                         if (caret.pos > caret.line.TextLengthWithoutEnding ()) {
1418                                                 if (!nowrap) {
1419                                                         // Go into next line
1420                                                         if (caret.line.line_no < this.lines) {
1421                                                                 caret.line = GetLine(caret.line.line_no+1);
1422                                                                 caret.pos = 0;
1423                                                                 caret.tag = caret.line.tags;
1424                                                         } else {
1425                                                                 caret.pos--;
1426                                                         }
1427                                                 } else {
1428                                                         // Single line; we stay where we are
1429                                                         caret.pos--;
1430                                                 }
1431                                         } else {
1432                                                 if ((caret.tag.Start - 1 + caret.tag.Length) < caret.pos) {
1433                                                         caret.tag = caret.tag.Next;
1434                                                 }
1435                                         }
1436                                         UpdateCaret();
1437                                         return;
1438                                 }
1439
1440                                 case CaretDirection.CharBackNoWrap:
1441                                         nowrap = true;
1442                                         goto case CaretDirection.CharBack;
1443                                 case CaretDirection.CharBack: {
1444                                         if (caret.pos > 0) {
1445                                                 // caret.pos--; // folded into the if below
1446
1447                                                 if (--caret.pos > 0) {
1448                                                         if (caret.tag.Start > caret.pos) {
1449                                                                 caret.tag = caret.tag.Previous;
1450                                                         }
1451                                                 }
1452                                         } else {
1453                                                 if (caret.line.line_no > 1 && !nowrap) {
1454                                                         caret.line = GetLine(caret.line.line_no - 1);
1455                                                         caret.pos = caret.line.TextLengthWithoutEnding ();
1456                                                         caret.tag = LineTag.FindTag(caret.line, caret.pos);
1457                                                 }
1458                                         }
1459                                         UpdateCaret();
1460                                         return;
1461                                 }
1462
1463                                 case CaretDirection.WordForward: {
1464                                         int len;
1465
1466                                         len = caret.line.text.Length;
1467                                         if (caret.pos < len) {
1468                                                 while ((caret.pos < len) && (caret.line.text[caret.pos] != ' ')) {
1469                                                         caret.pos++;
1470                                                 }
1471                                                 if (caret.pos < len) {
1472                                                         // Skip any whitespace
1473                                                         while ((caret.pos < len) && (caret.line.text[caret.pos] == ' ')) {
1474                                                                 caret.pos++;
1475                                                         }
1476                                                 }
1477                                                 caret.tag = LineTag.FindTag(caret.line, caret.pos);
1478                                         } else {
1479                                                 if (caret.line.line_no < this.lines) {
1480                                                         caret.line = GetLine(caret.line.line_no + 1);
1481                                                         caret.pos = 0;
1482                                                         caret.tag = caret.line.tags;
1483                                                 }
1484                                         }
1485                                         UpdateCaret();
1486                                         return;
1487                                 }
1488
1489                                 case CaretDirection.WordBack: {
1490                                         if (caret.pos > 0) {
1491                                                 caret.pos--;
1492
1493                                                 while ((caret.pos > 0) && (caret.line.text[caret.pos] == ' ')) {
1494                                                         caret.pos--;
1495                                                 }
1496
1497                                                 while ((caret.pos > 0) && (caret.line.text[caret.pos] != ' ')) {
1498                                                         caret.pos--;
1499                                                 }
1500
1501                                                 if (caret.line.text.ToString(caret.pos, 1) == " ") {
1502                                                         if (caret.pos != 0) {
1503                                                                 caret.pos++;
1504                                                         } else {
1505                                                                 caret.line = GetLine(caret.line.line_no - 1);
1506                                                                 caret.pos = caret.line.text.Length;
1507                                                         }
1508                                                 }
1509                                                 caret.tag = LineTag.FindTag(caret.line, caret.pos);
1510                                         } else {
1511                                                 if (caret.line.line_no > 1) {
1512                                                         caret.line = GetLine(caret.line.line_no - 1);
1513                                                         caret.pos = caret.line.text.Length;
1514                                                         caret.tag = LineTag.FindTag(caret.line, caret.pos);
1515                                                 }
1516                                         }
1517                                         UpdateCaret();
1518                                         return;
1519                                 }
1520
1521                                 case CaretDirection.LineUp: {
1522                                         if (caret.line.line_no > 1) {
1523                                                 int     pixel;
1524
1525                                                 pixel = (int)caret.line.widths[caret.pos];
1526                                                 PositionCaret(pixel, GetLine(caret.line.line_no - 1).Y);
1527
1528                                                 DisplayCaret ();
1529                                         }
1530                                         return;
1531                                 }
1532
1533                                 case CaretDirection.LineDown: {
1534                                         if (caret.line.line_no < lines) {
1535                                                 int     pixel;
1536
1537                                                 pixel = (int)caret.line.widths[caret.pos];
1538                                                 PositionCaret(pixel, GetLine(caret.line.line_no + 1).Y);
1539
1540                                                 DisplayCaret ();
1541                                         }
1542                                         return;
1543                                 }
1544
1545                                 case CaretDirection.Home: {
1546                                         if (caret.pos > 0) {
1547                                                 caret.pos = 0;
1548                                                 caret.tag = caret.line.tags;
1549                                                 UpdateCaret();
1550                                         }
1551                                         return;
1552                                 }
1553
1554                                 case CaretDirection.End: {
1555                                         if (caret.pos < caret.line.TextLengthWithoutEnding ()) {
1556                                                 caret.pos = caret.line.TextLengthWithoutEnding ();
1557                                                 caret.tag = LineTag.FindTag(caret.line, caret.pos);
1558                                                 UpdateCaret();
1559                                         }
1560                                         return;
1561                                 }
1562
1563                                 case CaretDirection.PgUp: {
1564
1565                                         if (caret.line.line_no == 1 && owner.richtext) {
1566                                                 owner.vscroll.Value = 0;
1567                                                 Line line = GetLine (1);
1568                                                 PositionCaret (line, 0);
1569                                         }
1570
1571                                         int y_offset = caret.line.Y + caret.line.height - 1 - viewport_y;
1572                                         int index;
1573                                         LineTag top = FindCursor ((int) caret.line.widths [caret.pos],
1574                                                         viewport_y - viewport_height, out index);
1575
1576                                         owner.vscroll.Value = Math.Min (top.Line.Y, owner.vscroll.Maximum - viewport_height);
1577                                         PositionCaret ((int) caret.line.widths [caret.pos], y_offset + viewport_y);
1578
1579                                         return;
1580                                 }
1581
1582                                 case CaretDirection.PgDn: {
1583
1584                                         if (caret.line.line_no == lines && owner.richtext) {
1585                                                 owner.vscroll.Value = owner.vscroll.Maximum - viewport_height + 1;
1586                                                 Line line = GetLine (lines);
1587                                                 PositionCaret (line, line.TextLengthWithoutEnding());
1588                                         }
1589
1590                                         int y_offset = caret.line.Y - viewport_y;
1591                                         int index;
1592                                         LineTag top = FindCursor ((int) caret.line.widths [caret.pos],
1593                                                         viewport_y + viewport_height, out index);
1594
1595                                         owner.vscroll.Value = Math.Min (top.Line.Y, owner.vscroll.Maximum - viewport_height);
1596                                         PositionCaret ((int) caret.line.widths [caret.pos], y_offset + viewport_y);
1597
1598                                         return;
1599                                 }
1600
1601                                 case CaretDirection.CtrlPgUp: {
1602                                         PositionCaret(0, viewport_y);
1603                                         DisplayCaret ();
1604                                         return;
1605                                 }
1606
1607                                 case CaretDirection.CtrlPgDn: {
1608                                         Line    line;
1609                                         LineTag tag;
1610                                         int     index;
1611
1612                                         tag = FindCursor (0, viewport_y + viewport_height, out index);
1613                                         if (tag.Line.line_no > 1) {
1614                                                 line = GetLine(tag.Line.line_no - 1);
1615                                         } else {
1616                                                 line = tag.Line;
1617                                         }
1618                                         PositionCaret(line, line.Text.Length);
1619                                         DisplayCaret ();
1620                                         return;
1621                                 }
1622
1623                                 case CaretDirection.CtrlHome: {
1624                                         caret.line = GetLine(1);
1625                                         caret.pos = 0;
1626                                         caret.tag = caret.line.tags;
1627
1628                                         UpdateCaret();
1629                                         return;
1630                                 }
1631
1632                                 case CaretDirection.CtrlEnd: {
1633                                         caret.line = GetLine(lines);
1634                                         caret.pos = caret.line.TextLengthWithoutEnding ();
1635                                         caret.tag = LineTag.FindTag(caret.line, caret.pos);
1636
1637                                         UpdateCaret();
1638                                         return;
1639                                 }
1640
1641                                 case CaretDirection.SelectionStart: {
1642                                         caret.line = selection_start.line;
1643                                         caret.pos = selection_start.pos;
1644                                         caret.tag = selection_start.tag;
1645
1646                                         UpdateCaret();
1647                                         return;
1648                                 }
1649
1650                                 case CaretDirection.SelectionEnd: {
1651                                         caret.line = selection_end.line;
1652                                         caret.pos = selection_end.pos;
1653                                         caret.tag = selection_end.tag;
1654
1655                                         UpdateCaret();
1656                                         return;
1657                                 }
1658                         }
1659                 }
1660
1661                 internal void DumpDoc ()
1662                 {
1663                         Console.WriteLine ("<doc lines='{0}'>", lines);
1664                         for (int i = 1; i <= lines ; i++) {
1665                                 Line line = GetLine (i);
1666                                 Console.WriteLine ("<line no='{0}' ending='{1}'>", line.line_no, line.ending);
1667
1668                                 LineTag tag = line.tags;
1669                                 while (tag != null) {
1670                                         Console.Write ("\t<tag type='{0}' span='{1}->{2}' font='{3}' color='{4}'>",
1671                                                         tag.GetType (), tag.Start, tag.Length, tag.Font, tag.Color);
1672                                         Console.Write (tag.Text ());
1673                                         Console.WriteLine ("</tag>");
1674                                         tag = tag.Next;
1675                                 }
1676                                 Console.WriteLine ("</line>");
1677                         }
1678                         Console.WriteLine ("</doc>");
1679                 }
1680
1681                 // UIA: Used via reflection by TextProviderBehavior
1682                 internal void GetVisibleLineIndexes (Rectangle clip, out int start, out int end)
1683                 {
1684                         if (multiline) {
1685                                 /* Expand the region slightly to be sure to
1686                                  * paint the full extent of the line of text.
1687                                  * See bug 464464.
1688                                  */
1689                                 start = GetLineByPixel(clip.Top + viewport_y - offset_y - 1, false).line_no;
1690                                 end = GetLineByPixel(clip.Bottom + viewport_y - offset_y + 1, false).line_no;
1691                         } else {
1692                                 start = GetLineByPixel(clip.Left + viewport_x - offset_x, false).line_no;
1693                                 end = GetLineByPixel(clip.Right + viewport_x - offset_x, false).line_no;
1694                         }
1695                 }
1696
1697                 internal void Draw (Graphics g, Rectangle clip)
1698                 {
1699                         Line line;              // Current line being drawn
1700                         LineTag tag;            // Current tag being drawn
1701                         int start;              // First line to draw
1702                         int end;                // Last line to draw
1703                         StringBuilder text;     // String representing the current line
1704                         int line_no;
1705                         Color tag_color;
1706                         Color current_color;
1707
1708                         // First, figure out from what line to what line we need to draw
1709                         GetVisibleLineIndexes (clip, out start, out end);
1710
1711                         // remove links in the list (used for mouse down events) that are within the clip area.
1712                         InvalidateLinks (clip);
1713
1714                         ///
1715                         /// We draw the single border ourself
1716                         ///
1717                         if (owner.actual_border_style == BorderStyle.FixedSingle) {
1718                                 ControlPaint.DrawBorder (g, owner.ClientRectangle, Color.Black, ButtonBorderStyle.Solid);
1719                         }
1720
1721                         /// Make sure that we aren't drawing one more line then we need to
1722                         line = GetLine (end - 1);
1723                         if (line != null && clip.Bottom == offset_y + line.Y + line.height - viewport_y)
1724                                 end--;
1725
1726                         line_no = start;
1727
1728                         #if Debug
1729                                 DateTime        n = DateTime.Now;
1730                                 Console.WriteLine ("Started drawing: {0}s {1}ms", n.Second, n.Millisecond);
1731                                 Console.WriteLine ("CLIP:  {0}", clip);
1732                                 Console.WriteLine ("S: {0}", GetLine (start).text);
1733                                 Console.WriteLine ("E: {0}", GetLine (end).text);
1734                         #endif
1735
1736                         // Non multiline selection can be handled outside of the loop
1737                         if (!multiline && selection_visible && owner.ShowSelection) {
1738                                 g.FillRectangle (ThemeEngine.Current.ResPool.GetSolidBrush (ThemeEngine.Current.ColorHighlight),
1739                                                 offset_x + selection_start.line.widths [selection_start.pos] +
1740                                                 selection_start.line.X - viewport_x,
1741                                                 offset_y + selection_start.line.Y,
1742                                                 (selection_end.line.X + selection_end.line.widths [selection_end.pos]) -
1743                                                 (selection_start.line.X + selection_start.line.widths [selection_start.pos]),
1744                                                 selection_start.line.height);
1745                         }
1746
1747                         while (line_no <= end) {
1748                                 line = GetLine (line_no);
1749                                 float line_y = line.Y - viewport_y + offset_y;
1750
1751                                 tag = line.tags;
1752                                 if (!calc_pass) {
1753                                         text = line.text;
1754                                 } else {
1755                                         if (PasswordCache.Length < line.text.Length)
1756                                                 PasswordCache.Append(Char.Parse(password_char), line.text.Length - PasswordCache.Length);
1757                                         else if (PasswordCache.Length > line.text.Length)
1758                                                 PasswordCache.Remove(line.text.Length, PasswordCache.Length - line.text.Length);
1759                                         text = PasswordCache;
1760                                 }
1761
1762                                 int line_selection_start = text.Length + 1;
1763                                 int line_selection_end = text.Length + 1;
1764                                 if (selection_visible && owner.ShowSelection &&
1765                                                 (line_no >= selection_start.line.line_no) &&
1766                                                 (line_no <= selection_end.line.line_no)) {
1767
1768                                         if (line_no == selection_start.line.line_no)
1769                                                 line_selection_start = selection_start.pos + 1;
1770                                         else
1771                                                 line_selection_start = 1;
1772
1773                                         if (line_no == selection_end.line.line_no)
1774                                                 line_selection_end = selection_end.pos + 1;
1775                                         else
1776                                                 line_selection_end = text.Length + 1;
1777
1778                                         if (line_selection_end == line_selection_start) {
1779                                                 // There isn't really selection
1780                                                 line_selection_start = text.Length + 1;
1781                                                 line_selection_end = line_selection_start;
1782                                         } else if (multiline) {
1783                                                 // lets draw some selection baby!!  (non multiline selection is drawn outside the loop)
1784                                                 g.FillRectangle (ThemeEngine.Current.ResPool.GetSolidBrush (ThemeEngine.Current.ColorHighlight),
1785                                                                 offset_x + line.widths [line_selection_start - 1] + line.X - viewport_x,
1786                                                                 line_y, line.widths [line_selection_end - 1] - line.widths [line_selection_start - 1],
1787                                                                 line.height);
1788                                         }
1789                                 }
1790
1791                                 current_color = line.tags.ColorToDisplay;
1792                                 while (tag != null) {
1793
1794                                         // Skip empty tags
1795                                         if (tag.Length == 0) {
1796                                                 tag = tag.Next;
1797                                                 continue;
1798                                         }
1799
1800                                         if (((tag.X + tag.Width) < (clip.Left - viewport_x - offset_x)) &&
1801                                              (tag.X > (clip.Right - viewport_x - offset_x))) {
1802                                                 tag = tag.Next;
1803                                                 continue;
1804                                         }
1805
1806                                         if (tag.BackColor != Color.Empty) {
1807                                                 g.FillRectangle (ThemeEngine.Current.ResPool.GetSolidBrush (tag.BackColor),
1808                                                                 offset_x + tag.X + line.X - viewport_x,
1809                                                                 line_y + tag.Shift, tag.Width, line.height);
1810                                         }
1811
1812                                         tag_color = tag.ColorToDisplay;
1813                                         current_color = tag_color;
1814
1815                                         if (!owner.Enabled) {
1816                                                 Color a = tag.Color;
1817                                                 Color b = ThemeEngine.Current.ColorWindowText;
1818
1819                                                 if ((a.R == b.R) && (a.G == b.G) && (a.B == b.B))
1820                                                         tag_color = ThemeEngine.Current.ColorGrayText;
1821
1822                                         }
1823
1824                                         int tag_pos = tag.Start;
1825                                         current_color = tag_color;
1826                                         while (tag_pos < tag.Start + tag.Length) {
1827                                                 int old_tag_pos = tag_pos;
1828
1829                                                 if (tag_pos >= line_selection_start && tag_pos < line_selection_end) {
1830                                                         current_color = ThemeEngine.Current.ColorHighlightText;
1831                                                         tag_pos = Math.Min (tag.End, line_selection_end);
1832                                                 } else if (tag_pos < line_selection_start) {
1833                                                         current_color = tag_color;
1834                                                         tag_pos = Math.Min (tag.End, line_selection_start);
1835                                                 } else {
1836                                                         current_color = tag_color;
1837                                                         tag_pos = tag.End;
1838                                                 }
1839
1840                                                 Rectangle text_size;
1841
1842                                                 tag.Draw (g, current_color,
1843                                                                 offset_x + line.X - viewport_x,
1844                                                                 line_y + tag.Shift,
1845                                                                 old_tag_pos - 1, Math.Min (tag.Start + tag.Length, tag_pos) - 1,
1846                                                                 text.ToString (), out text_size, tag.IsLink);
1847
1848                                                 if (tag.IsLink) {
1849                                                         TextBoxBase.LinkRectangle link = new TextBoxBase.LinkRectangle (text_size);
1850                                                         link.LinkTag = tag;
1851                                                         owner.list_links.Add (link);
1852                                                 }
1853                                         }
1854                                         tag = tag.Next;
1855                                 }
1856
1857                                 line.DrawEnding (g, line_y);
1858                                 line_no++;
1859                         }
1860                 }
1861
1862                 private int GetLineEnding (string line, int start, out LineEnding ending)
1863                 {
1864                         int res;
1865                         int rich_index;
1866
1867                         if (start >= line.Length) {
1868                                 ending = LineEnding.Wrap;
1869                                 return -1;
1870                         }
1871
1872                         res = line.IndexOf ('\r', start);
1873                         rich_index = line.IndexOf ('\n', start);
1874
1875                         // Handle the case where we find both of them, and the \n is before the \r
1876                         if (res != -1 && rich_index != -1)
1877                                 if (rich_index < res) {
1878                                         ending = LineEnding.Rich;
1879                                         return rich_index;
1880                                 }
1881
1882                         if (res != -1) {
1883                                 if (res + 2 < line.Length && line [res + 1] == '\r' && line [res + 2] == '\n') {
1884                                         ending = LineEnding.Soft;
1885                                         return res;
1886                                 }
1887                                 if (res + 1 < line.Length && line [res + 1] == '\n') {
1888                                         ending = LineEnding.Hard;
1889                                         return res;
1890                                 }
1891                                 ending = LineEnding.Limp;
1892                                 return res;
1893                         }
1894
1895                         if (rich_index != -1) {
1896                                 ending = LineEnding.Rich;
1897                                 return rich_index;
1898                         }
1899
1900                         ending = LineEnding.Wrap;
1901                         return line.Length;
1902                 }
1903
1904                 // Get the line ending, but only of the types specified
1905                 private int GetLineEnding (string line, int start, out LineEnding ending, LineEnding type)
1906                 {
1907                         int index = start;
1908                         int last_length = 0;
1909
1910                         do {
1911                                 index = GetLineEnding (line, index + last_length, out ending);
1912                                 last_length = LineEndingLength (ending);
1913                         } while
1914                                 ((ending & type) != ending && index != -1);
1915
1916                         return index == -1 ? line.Length : index;
1917                 }
1918
1919                 internal int LineEndingLength (LineEnding ending)
1920                 {
1921                         switch (ending) {
1922                                 case LineEnding.Limp:
1923                                 case LineEnding.Rich:
1924                                         return 1;
1925                                 case LineEnding.Hard:
1926                                         return 2;
1927                                 case LineEnding.Soft:
1928                                         return 3;
1929                         }
1930
1931                         return 0;
1932                 }
1933
1934                 internal string LineEndingToString (LineEnding ending)
1935                 {
1936                         switch (ending) {
1937                                 case LineEnding.Limp:
1938                                         return "\r";
1939                                 case LineEnding.Hard:
1940                                         return "\r\n";
1941                                 case LineEnding.Soft:
1942                                         return "\r\r\n";
1943                                 case LineEnding.Rich:
1944                                         return "\n";
1945                         }
1946
1947                         return string.Empty;
1948                 }
1949
1950                 internal LineEnding StringToLineEnding (string ending)
1951                 {
1952                         switch (ending) {
1953                                 case "\r":
1954                                         return LineEnding.Limp;
1955                                 case "\r\n":
1956                                         return LineEnding.Hard;
1957                                 case "\r\r\n":
1958                                         return LineEnding.Soft;
1959                                 case "\n":
1960                                         return LineEnding.Rich;
1961                                 default:
1962                                         return LineEnding.None;
1963                         }
1964                 }
1965
1966                 internal void Insert (Line line, int pos, bool update_caret, string s)
1967                 {
1968                         Insert (line, pos, update_caret, s, line.FindTag (pos));
1969                 }
1970
1971                 // Insert text at the given position; use formatting at insertion point for inserted text
1972                 internal void Insert (Line line, int pos, bool update_caret, string s, LineTag tag)
1973                 {
1974                         int break_index;
1975                         int base_line;
1976                         int old_line_count;
1977                         int count = 1;
1978                         LineEnding ending;
1979                         Line split_line;
1980
1981                         // Don't recalculate while we mess around
1982                         SuspendRecalc ();
1983
1984                         base_line = line.line_no;
1985                         old_line_count = lines;
1986
1987                         // Discard chars after any possible -unlikely- end of file
1988                         int eof_index = s.IndexOf ('\0');
1989                         if (eof_index != -1)
1990                                 s = s.Substring (0, eof_index);
1991
1992                         break_index = GetLineEnding (s, 0, out ending, LineEnding.Hard | LineEnding.Rich);
1993
1994                         // There are no line feeds in our text to be pasted
1995                         if (break_index == s.Length) {
1996                                 line.InsertString (pos, s, tag);
1997                         } else {
1998                                 // Add up to the first line feed to our current position
1999                                 line.InsertString (pos, s.Substring (0, break_index + LineEndingLength (ending)), tag);
2000
2001                                 // Split the rest of the original line to a new line
2002                                 Split (line, pos + (break_index + LineEndingLength (ending)));
2003                                 line.ending = ending;
2004                                 break_index += LineEndingLength (ending);
2005                                 split_line = GetLine (line.line_no + 1);
2006
2007                                 // Insert brand new lines for any more line feeds in the inserted string
2008                                 while (true) {
2009                                         int next_break = GetLineEnding (s, break_index, out ending, LineEnding.Hard | LineEnding.Rich);
2010
2011                                         if (next_break == s.Length)
2012                                                 break;
2013
2014                                         string line_text = s.Substring (break_index, next_break - break_index +
2015                                                         LineEndingLength (ending));
2016
2017                                         Add (base_line + count, line_text, line.alignment, tag.Font, tag.Color, ending);
2018
2019                                         Line last = GetLine (base_line + count);
2020                                         last.ending = ending;
2021
2022                                         count++;
2023                                         break_index = next_break + LineEndingLength (ending);
2024                                 }
2025
2026                                 // Add the remainder of the insert text to the split
2027                                 // part of the original line
2028                                 split_line.InsertString (0, s.Substring (break_index));
2029                         }
2030
2031                         // Allow the document to recalculate things
2032                         ResumeRecalc (false);
2033
2034                         // Update our character count
2035                         CharCount += s.Length;
2036
2037                         UpdateView (line, lines - old_line_count + 1, pos);
2038
2039                         // Move the caret to the end of the inserted text if requested
2040                         if (update_caret) {
2041                                 Line l = GetLine (line.line_no + lines - old_line_count);
2042                                 PositionCaret (l, l.text.Length);
2043                                 DisplayCaret ();
2044                         }
2045                 }
2046
2047                 // Inserts a string at the given position
2048                 internal void InsertString (Line line, int pos, string s)
2049                 {
2050                         // Update our character count
2051                         CharCount += s.Length;
2052
2053                         // Insert the text into the Line
2054                         line.InsertString (pos, s);
2055                 }
2056
2057                 // Inserts a character at the current caret position
2058                 internal void InsertCharAtCaret (char ch, bool move_caret)
2059                 {
2060                         caret.line.InsertString (caret.pos, ch.ToString(), caret.tag);
2061
2062                         // Update our character count
2063                         CharCount++;
2064
2065                         undo.RecordTyping (caret.line, caret.pos, ch);
2066
2067                         UpdateView (caret.line, caret.pos);
2068
2069                         if (move_caret) {
2070                                 caret.pos++;
2071                                 UpdateCaret ();
2072                                 SetSelectionToCaret (true);
2073                         }
2074                 }
2075
2076                 internal void InsertPicture (Line line, int pos, RTF.Picture picture)
2077                 {
2078                         //LineTag next_tag;
2079                         LineTag tag;
2080                         int len;
2081
2082                         len = 1;
2083
2084                         // Just a place holder basically
2085                         line.text.Insert (pos, "I");
2086
2087                         PictureTag picture_tag = new PictureTag (line, pos + 1, picture);
2088
2089                         tag = LineTag.FindTag (line, pos);
2090                         picture_tag.CopyFormattingFrom (tag);
2091                         /*next_tag = */tag.Break (pos + 1);
2092                         picture_tag.Previous = tag;
2093                         picture_tag.Next = tag.Next;
2094                         tag.Next = picture_tag;
2095
2096                         //
2097                         // Picture tags need to be surrounded by text tags
2098                         //
2099                         if (picture_tag.Next == null) {
2100                                 picture_tag.Next = new LineTag (line, pos + 1);
2101                                 picture_tag.Next.CopyFormattingFrom (tag);
2102                                 picture_tag.Next.Previous = picture_tag;
2103                         }
2104
2105                         tag = picture_tag.Next;
2106                         while (tag != null) {
2107                                 tag.Start += len;
2108                                 tag = tag.Next;
2109                         }
2110
2111                         line.Grow (len);
2112                         line.recalc = true;
2113
2114                         UpdateView (line, pos);
2115                 }
2116
2117                 internal void DeleteMultiline (Line start_line, int pos, int length)
2118                 {
2119                         Marker start = new Marker ();
2120                         Marker end = new Marker ();
2121                         int start_index = LineTagToCharIndex (start_line, pos);
2122
2123                         start.line = start_line;
2124                         start.pos = pos;
2125                         start.tag = LineTag.FindTag (start_line, pos);
2126
2127                         CharIndexToLineTag (start_index + length, out end.line,
2128                                         out end.tag, out end.pos);
2129
2130                         SuspendUpdate ();
2131
2132                         if (start.line == end.line) {
2133                                 DeleteChars (start.line, pos, end.pos - pos);
2134                         } else {
2135
2136                                 // Delete first and last lines
2137                                 DeleteChars (start.line, start.pos, start.line.text.Length - start.pos);
2138                                 DeleteChars (end.line, 0, end.pos);
2139
2140                                 int current = start.line.line_no + 1;
2141                                 if (current < end.line.line_no) {
2142                                         for (int i = end.line.line_no - 1; i >= current; i--) {
2143                                                 Delete (i);
2144                                         }
2145                                 }
2146
2147                                 // BIG FAT WARNING - selection_end.line might be stale due
2148                                 // to the above Delete() call. DONT USE IT before hitting the end of this method!
2149
2150                                 // Join start and end
2151                                 Combine (start.line.line_no, current);
2152                         }
2153
2154                         ResumeUpdate (true);
2155                 }
2156
2157
2158                 // Deletes n characters at the given position; it will not delete past line limits
2159                 // pos is 0-based
2160                 public void DeleteChars (Line line, int pos, int count)
2161                 {
2162                         // Reduce our character count
2163                         CharCount -= count;
2164
2165                         line.DeleteCharacters (pos, count);
2166
2167                         if (pos >= line.TextLengthWithoutEnding ()) {
2168                                 LineEnding ending = line.ending;
2169                                 GetLineEnding (line.text.ToString (), 0, out ending);
2170
2171                                 if (ending != line.ending) {
2172                                         line.ending = ending;
2173
2174                                         if (!multiline) {
2175                                                 UpdateView (line, lines, pos);
2176                                                 owner.Invalidate ();
2177                                                 return;
2178                                         }
2179                                 }
2180                         }
2181                         if (!multiline) {
2182                                 UpdateView (line, lines, pos);
2183                                 owner.Invalidate ();
2184                         } else
2185                                 UpdateView (line, pos);
2186                 }
2187
2188                 // Deletes a character at or after the given position (depending on forward); it will not delete past line limits
2189                 public void DeleteChar (Line line, int pos, bool forward)
2190                 {
2191                         if ((pos == 0 && forward == false) || (pos == line.text.Length && forward == true))
2192                                 return;
2193
2194                         undo.BeginUserAction ("Delete");
2195
2196                         if (forward) {
2197                                 undo.RecordDeleteString (line, pos, line, pos + 1);
2198                                 DeleteChars (line, pos, 1);
2199                         } else {
2200                                 undo.RecordDeleteString (line, pos - 1, line, pos);
2201                                 DeleteChars (line, pos - 1, 1);
2202                         }
2203
2204                         undo.EndUserAction ();
2205                 }
2206
2207                 // Combine two lines
2208                 internal void Combine(int FirstLine, int SecondLine) {
2209                         Combine(GetLine(FirstLine), GetLine(SecondLine));
2210                 }
2211
2212                 internal void Combine(Line first, Line second) {
2213                         LineTag last;
2214                         int     shift;
2215
2216                         // strip the ending off of the first lines text
2217                         first.text.Length = first.text.Length - LineEndingLength (first.ending);
2218
2219                         // Combine the two tag chains into one
2220                         last = first.tags;
2221
2222                         // Maintain the line ending style
2223                         first.ending = second.ending;
2224
2225                         while (last.Next != null) {
2226                                 last = last.Next;
2227                         }
2228
2229                         // need to get the shift before setting the next tag since that effects length
2230                         shift = last.Start + last.Length - 1;
2231                         last.Next = second.tags;
2232                         last.Next.Previous = last;
2233
2234                         // Fix up references within the chain
2235                         last = last.Next;
2236                         while (last != null) {
2237                                 last.Line = first;
2238                                 last.Start += shift;
2239                                 last = last.Next;
2240                         }
2241
2242                         // Combine both lines' strings
2243                         first.text.Insert(first.text.Length, second.text.ToString());
2244                         first.Grow(first.text.Length);
2245
2246                         // Remove the reference to our (now combined) tags from the doomed line
2247                         second.tags = null;
2248
2249                         // Renumber lines
2250                         DecrementLines(first.line_no + 2);      // first.line_no + 1 will be deleted, so we need to start renumbering one later
2251
2252                         // Mop up
2253                         first.recalc = true;
2254                         first.height = 0;       // This forces RecalcDocument/UpdateView to redraw from this line on
2255                         first.Streamline(lines);
2256
2257                         // Update Caret, Selection, etc
2258                         if (caret.line == second) {
2259                                 caret.Combine(first, shift);
2260                         }
2261                         if (selection_anchor.line == second) {
2262                                 selection_anchor.Combine(first, shift);
2263                         }
2264                         if (selection_start.line == second) {
2265                                 selection_start.Combine(first, shift);
2266                         }
2267                         if (selection_end.line == second) {
2268                                 selection_end.Combine(first, shift);
2269                         }
2270
2271                         #if Debug
2272                                 Line    check_first;
2273                                 Line    check_second;
2274
2275                                 check_first = GetLine(first.line_no);
2276                                 check_second = GetLine(check_first.line_no + 1);
2277
2278                                 Console.WriteLine("Pre-delete: Y of first line: {0}, second line: {1}", check_first.Y, check_second.Y);
2279                         #endif
2280
2281                         this.Delete(second);
2282
2283                         #if Debug
2284                                 check_first = GetLine(first.line_no);
2285                                 check_second = GetLine(check_first.line_no + 1);
2286
2287                                 Console.WriteLine("Post-delete Y of first line: {0}, second line: {1}", check_first.Y, check_second.Y);
2288                         #endif
2289                 }
2290
2291                 // Split the line at the position into two
2292                 internal void Split(int LineNo, int pos) {
2293                         Line    line;
2294                         LineTag tag;
2295
2296                         line = GetLine(LineNo);
2297                         tag = LineTag.FindTag(line, pos);
2298                         Split(line, tag, pos);
2299                 }
2300
2301                 internal void Split(Line line, int pos) {
2302                         LineTag tag;
2303
2304                         tag = LineTag.FindTag(line, pos);
2305                         Split(line, tag, pos);
2306                 }
2307
2308                 ///<summary>Split line at given tag and position into two lines</summary>
2309                 ///if more space becomes available on previous line
2310                 internal void Split(Line line, LineTag tag, int pos) {
2311                         LineTag new_tag;
2312                         Line    new_line;
2313                         bool    move_caret;
2314                         bool    move_sel_start;
2315                         bool    move_sel_end;
2316
2317                         move_caret = false;
2318                         move_sel_start = false;
2319                         move_sel_end = false;
2320
2321 #if DEBUG
2322                         SanityCheck();
2323
2324                         if (tag.End < pos)
2325                                 throw new Exception ("Split called with the wrong tag");
2326 #endif
2327
2328                         // Adjust selection and cursors
2329                         if (caret.line == line && caret.pos >= pos) {
2330                                 move_caret = true;
2331                         }
2332                         if (selection_start.line == line && selection_start.pos > pos) {
2333                                 move_sel_start = true;
2334                         }
2335
2336                         if (selection_end.line == line && selection_end.pos > pos) {
2337                                 move_sel_end = true;
2338                         }
2339
2340                         // cover the easy case first
2341                         if (pos == line.text.Length) {
2342                                 Add (line.line_no + 1, String.Empty, line.alignment, tag.Font, tag.Color, line.ending);
2343
2344                                 new_line = GetLine (line.line_no + 1);
2345
2346                                 if (move_caret) {
2347                                         caret.line = new_line;
2348                                         caret.tag = new_line.tags;
2349                                         caret.pos = 0;
2350
2351                                         if (selection_visible == false) {
2352                                                 SetSelectionToCaret (true);
2353                                         }
2354                                 }
2355
2356                                 if (move_sel_start) {
2357                                         selection_start.line = new_line;
2358                                         selection_start.pos = 0;
2359                                         selection_start.tag = new_line.tags;
2360                                 }
2361
2362                                 if (move_sel_end) {
2363                                         selection_end.line = new_line;
2364                                         selection_end.pos = 0;
2365                                         selection_end.tag = new_line.tags;
2366                                 }
2367
2368 #if DEBUG
2369                                 SanityCheck ();
2370 #endif
2371                                 return;
2372                         }
2373
2374                         // We need to move the rest of the text into the new line
2375                         Add (line.line_no + 1, line.text.ToString (pos, line.text.Length - pos), line.alignment, tag.Font, tag.Color, line.ending);
2376
2377                         // Now transfer our tags from this line to the next
2378                         new_line = GetLine(line.line_no + 1);
2379
2380                         line.recalc = true;
2381                         new_line.recalc = true;
2382
2383                         //make sure that if we are at the end of a tag, we start on the begining
2384                         //of a new one, if one exists... Stops us creating an empty tag and
2385                         //make the operation easier.
2386                         if (tag.Next != null && (tag.Next.Start - 1) == pos)
2387                                 tag = tag.Next;
2388
2389                         if ((tag.Start - 1) == pos) {
2390                                 int     shift;
2391
2392                                 // We can simply break the chain and move the tag into the next line
2393
2394                                 // if the tag we are moving is the first, create an empty tag
2395                                 // for the line we are leaving behind
2396                                 if (tag == line.tags) {
2397                                         new_tag = new LineTag(line, 1);
2398                                         new_tag.CopyFormattingFrom (tag);
2399                                         line.tags = new_tag;
2400                                 }
2401
2402                                 if (tag.Previous != null) {
2403                                         tag.Previous.Next = null;
2404                                 }
2405                                 new_line.tags = tag;
2406                                 tag.Previous = null;
2407                                 tag.Line = new_line;
2408
2409                                 // Walk the list and correct the start location of the tags we just bumped into the next line
2410                                 shift = tag.Start - 1;
2411
2412                                 new_tag = tag;
2413                                 while (new_tag != null) {
2414                                         new_tag.Start -= shift;
2415                                         new_tag.Line = new_line;
2416                                         new_tag = new_tag.Next;
2417                                 }
2418                         } else {
2419                                 int     shift;
2420
2421                                 new_tag = new LineTag (new_line, 1);
2422                                 new_tag.Next = tag.Next;
2423                                 new_tag.CopyFormattingFrom (tag);
2424                                 new_line.tags = new_tag;
2425                                 if (new_tag.Next != null) {
2426                                         new_tag.Next.Previous = new_tag;
2427                                 }
2428                                 tag.Next = null;
2429
2430                                 shift = pos;
2431                                 new_tag = new_tag.Next;
2432                                 while (new_tag != null) {
2433                                         new_tag.Start -= shift;
2434                                         new_tag.Line = new_line;
2435                                         new_tag = new_tag.Next;
2436
2437                                 }
2438                         }
2439
2440                         if (move_caret) {
2441                                 caret.line = new_line;
2442                                 caret.pos = caret.pos - pos;
2443                                 caret.tag = caret.line.FindTag(caret.pos);
2444
2445                                 if (selection_visible == false) {
2446                                         SetSelectionToCaret (true);
2447                                 }
2448                         }
2449
2450                         if (move_sel_start) {
2451                                 selection_start.line = new_line;
2452                                 selection_start.pos = selection_start.pos - pos;
2453                                 if  (selection_start.Equals(selection_end))
2454                                         selection_start.tag = new_line.FindTag(selection_start.pos);
2455                                 else
2456                                         selection_start.tag = new_line.FindTag (selection_start.pos + 1);
2457                         }
2458
2459                         if (move_sel_end) {
2460                                 selection_end.line = new_line;
2461                                 selection_end.pos = selection_end.pos - pos;
2462                                 selection_end.tag = new_line.FindTag(selection_end.pos);
2463                         }
2464
2465                         CharCount -= line.text.Length - pos;
2466                         line.text.Remove(pos, line.text.Length - pos);
2467 #if DEBUG
2468                         SanityCheck ();
2469 #endif
2470                 }
2471
2472 #if DEBUG
2473                 private void SanityCheck () {
2474                         for (int i = 1; i < lines; i++) {
2475                                 LineTag tag = GetLine (i).tags;
2476
2477                                 if (tag.Start != 1)
2478                                         throw new Exception ("Line doesn't start at the begining");
2479
2480                                 int start = 1;
2481                                 tag = tag.Next;
2482
2483                                 while (tag != null) {
2484                                         if (tag.Start == start)
2485                                                 throw new Exception ("Empty tag!");
2486
2487                                         if (tag.Start < start)
2488                                                 throw new Exception ("Insane!!");
2489
2490                                         start = tag.Start;
2491                                         tag = tag.Next;
2492                                 }
2493                         }
2494                 }
2495 #endif
2496
2497                 // Adds a line of text, with given font.
2498                 // Bumps any line at that line number that already exists down
2499                 internal void Add (int LineNo, string Text, Font font, Color color, LineEnding ending)
2500                 {
2501                         Add (LineNo, Text, alignment, font, color, ending);
2502                 }
2503
2504                 internal void Add (int LineNo, string Text, HorizontalAlignment align, Font font, Color color, LineEnding ending)
2505                 {
2506                         Line    add;
2507                         Line    line;
2508                         int     line_no;
2509
2510                         CharCount += Text.Length;
2511
2512                         if (LineNo<1 || Text == null) {
2513                                 if (LineNo<1) {
2514                                         throw new ArgumentNullException("LineNo", "Line numbers must be positive");
2515                                 } else {
2516                                         throw new ArgumentNullException("Text", "Cannot insert NULL line");
2517                                 }
2518                         }
2519
2520                         add = new Line (this, LineNo, Text, align, font, color, ending);
2521
2522                         line = document;
2523                         while (line != sentinel) {
2524                                 add.parent = line;
2525                                 line_no = line.line_no;
2526
2527                                 if (LineNo > line_no) {
2528                                         line = line.right;
2529                                 } else if (LineNo < line_no) {
2530                                         line = line.left;
2531                                 } else {
2532                                         // Bump existing line numbers; walk all nodes to the right of this one and increment line_no
2533                                         IncrementLines(line.line_no);
2534                                         line = line.left;
2535                                 }
2536                         }
2537
2538                         add.left = sentinel;
2539                         add.right = sentinel;
2540
2541                         if (add.parent != null) {
2542                                 if (LineNo > add.parent.line_no) {
2543                                         add.parent.right = add;
2544                                 } else {
2545                                         add.parent.left = add;
2546                                 }
2547                         } else {
2548                                 // Root node
2549                                 document = add;
2550                         }
2551
2552                         RebalanceAfterAdd(add);
2553
2554                         lines++;
2555                 }
2556
2557                 internal virtual void Clear() {
2558                         lines = 0;
2559                         CharCount = 0;
2560                         document = sentinel;
2561                 }
2562
2563                 public virtual object Clone() {
2564                         Document clone;
2565
2566                         clone = new Document(null);
2567
2568                         clone.lines = this.lines;
2569                         clone.document = (Line)document.Clone();
2570
2571                         return clone;
2572                 }
2573
2574                 private void Delete (int LineNo)
2575                 {
2576                         Line    line;
2577
2578                         if (LineNo > lines)
2579                                 return;
2580
2581                         line = GetLine (LineNo);
2582
2583                         CharCount -= line.text.Length;
2584
2585                         DecrementLines (LineNo + 1);
2586                         Delete (line);
2587                 }
2588
2589                 private void Delete(Line line1) {
2590                         Line    line2;// = new Line();
2591                         Line    line3;
2592
2593                         if ((line1.left == sentinel) || (line1.right == sentinel)) {
2594                                 line3 = line1;
2595                         } else {
2596                                 line3 = line1.right;
2597                                 while (line3.left != sentinel) {
2598                                         line3 = line3.left;
2599                                 }
2600                         }
2601
2602                         if (line3.left != sentinel) {
2603                                 line2 = line3.left;
2604                         } else {
2605                                 line2 = line3.right;
2606                         }
2607
2608                         line2.parent = line3.parent;
2609                         if (line3.parent != null) {
2610                                 if(line3 == line3.parent.left) {
2611                                         line3.parent.left = line2;
2612                                 } else {
2613                                         line3.parent.right = line2;
2614                                 }
2615                         } else {
2616                                 document = line2;
2617                         }
2618
2619                         if (line3 != line1) {
2620                                 LineTag tag;
2621
2622                                 if (selection_start.line == line3) {
2623                                         selection_start.line = line1;
2624                                 }
2625
2626                                 if (selection_end.line == line3) {
2627                                         selection_end.line = line1;
2628                                 }
2629
2630                                 if (selection_anchor.line == line3) {
2631                                         selection_anchor.line = line1;
2632                                 }
2633
2634                                 if (caret.line == line3) {
2635                                         caret.line = line1;
2636                                 }
2637
2638
2639                                 line1.alignment = line3.alignment;
2640                                 line1.ascent = line3.ascent;
2641                                 line1.hanging_indent = line3.hanging_indent;
2642                                 line1.height = line3.height;
2643                                 line1.indent = line3.indent;
2644                                 line1.line_no = line3.line_no;
2645                                 line1.recalc = line3.recalc;
2646                                 line1.right_indent = line3.right_indent;
2647                                 line1.ending = line3.ending;
2648                                 line1.space = line3.space;
2649                                 line1.tags = line3.tags;
2650                                 line1.text = line3.text;
2651                                 line1.widths = line3.widths;
2652                                 line1.offset = line3.offset;
2653
2654                                 tag = line1.tags;
2655                                 while (tag != null) {
2656                                         tag.Line = line1;
2657                                         tag = tag.Next;
2658                                 }
2659                         }
2660
2661                         if (line3.color == LineColor.Black)
2662                                 RebalanceAfterDelete(line2);
2663
2664                         this.lines--;
2665                 }
2666
2667                 // Invalidates the start line until the end of the viewstate
2668                 internal void InvalidateLinesAfter (Line start) {
2669                         owner.Invalidate (new Rectangle (0, start.Y - viewport_y, viewport_width, viewport_height - start.Y));
2670                 }
2671
2672                 // Invalidate a section of the document to trigger redraw
2673                 internal void Invalidate(Line start, int start_pos, Line end, int end_pos) {
2674                         Line    l1;
2675                         Line    l2;
2676                         int     p1;
2677                         int     p2;
2678
2679                         if ((start == end) && (start_pos == end_pos)) {
2680                                 return;
2681                         }
2682
2683                         if (end_pos == -1) {
2684                                 end_pos = end.text.Length;
2685                         }
2686
2687                         // figure out what's before what so the logic below is straightforward
2688                         if (start.line_no < end.line_no) {
2689                                 l1 = start;
2690                                 p1 = start_pos;
2691
2692                                 l2 = end;
2693                                 p2 = end_pos;
2694                         } else if (start.line_no > end.line_no) {
2695                                 l1 = end;
2696                                 p1 = end_pos;
2697
2698                                 l2 = start;
2699                                 p2 = start_pos;
2700                         } else {
2701                                 if (start_pos < end_pos) {
2702                                         l1 = start;
2703                                         p1 = start_pos;
2704
2705                                         l2 = end;
2706                                         p2 = end_pos;
2707                                 } else {
2708                                         l1 = end;
2709                                         p1 = end_pos;
2710
2711                                         l2 = start;
2712                                         p2 = start_pos;
2713                                 }
2714
2715                                 int endpoint = (int) l1.widths [p2];
2716                                 if (p2 == l1.text.Length + 1) {
2717                                         endpoint = (int) viewport_width;
2718                                 }
2719
2720                                 #if Debug
2721                                         Console.WriteLine("Invaliding backwards from {0}:{1} to {2}:{3}   {4}",
2722                                                         l1.line_no, p1, l2.line_no, p2,
2723                                                         new Rectangle(
2724                                                                 (int)l1.widths[p1] + l1.X - viewport_x,
2725                                                                 l1.Y - viewport_y,
2726                                                                 (int)l1.widths[p2],
2727                                                                 l1.height
2728                                                                 )
2729                                                 );
2730                                 #endif
2731
2732                                 owner.Invalidate(new Rectangle (
2733                                         offset_x + (int)l1.widths[p1] + l1.X - viewport_x,
2734                                         offset_y + l1.Y - viewport_y,
2735                                         endpoint - (int) l1.widths [p1] + 1,
2736                                         l1.height));
2737                                 return;
2738                         }
2739
2740                         #if Debug
2741                                 Console.WriteLine("Invaliding from {0}:{1} to {2}:{3} Start  => x={4}, y={5}, {6}x{7}", l1.line_no, p1, l2.line_no, p2, (int)l1.widths[p1] + l1.X - viewport_x, l1.Y - viewport_y, viewport_width, l1.height);
2742                                 Console.WriteLine ("invalidate start line:  {0}  position:  {1}", l1.text, p1);
2743                         #endif
2744
2745                         // Three invalidates:
2746                         // First line from start
2747                         owner.Invalidate(new Rectangle(
2748                                 offset_x + (int)l1.widths[p1] + l1.X - viewport_x,
2749                                 offset_y + l1.Y - viewport_y,
2750                                 viewport_width,
2751                                 l1.height));
2752
2753
2754                         // lines inbetween
2755                         if ((l1.line_no + 1) < l2.line_no) {
2756                                 int     y;
2757
2758                                 y = GetLine(l1.line_no + 1).Y;
2759                                 owner.Invalidate(new Rectangle(
2760                                         offset_x,
2761                                         offset_y + y - viewport_y,
2762                                         viewport_width,
2763                                         l2.Y - y));
2764
2765                                 #if Debug
2766                                         Console.WriteLine("Invaliding from {0}:{1} to {2}:{3} Middle => x={4}, y={5}, {6}x{7}", l1.line_no, p1, l2.line_no, p2, 0, y - viewport_y, viewport_width, l2.Y - y);
2767                                 #endif
2768                         }
2769
2770
2771                         // Last line to end
2772                         owner.Invalidate(new Rectangle(
2773                                 offset_x + (int)l2.widths[0] + l2.X - viewport_x,
2774                                 offset_y + l2.Y - viewport_y,
2775                                 (int)l2.widths[p2] + 1,
2776                                 l2.height));
2777
2778                         #if Debug
2779                                 Console.WriteLine("Invaliding from {0}:{1} to {2}:{3} End    => x={4}, y={5}, {6}x{7}", l1.line_no, p1, l2.line_no, p2, (int)l2.widths[0] + l2.X - viewport_x, l2.Y - viewport_y, (int)l2.widths[p2] + 1, l2.height);
2780                         #endif
2781                 }
2782
2783                 /// <summary>Select text around caret</summary>
2784                 internal void ExpandSelection(CaretSelection mode, bool to_caret) {
2785                         if (to_caret) {
2786                                 // We're expanding the selection to the caret position
2787                                 switch(mode) {
2788                                         case CaretSelection.Line: {
2789                                                 // Invalidate the selection delta
2790                                                 if (caret > selection_prev) {
2791                                                         Invalidate(selection_prev.line, 0, caret.line, caret.line.text.Length);
2792                                                 } else {
2793                                                         Invalidate(selection_prev.line, selection_prev.line.text.Length, caret.line, 0);
2794                                                 }
2795
2796                                                 if (caret.line.line_no <= selection_anchor.line.line_no) {
2797                                                         selection_start.line = caret.line;
2798                                                         selection_start.tag = caret.line.tags;
2799                                                         selection_start.pos = 0;
2800
2801                                                         selection_end.line = selection_anchor.line;
2802                                                         selection_end.tag = selection_anchor.tag;
2803                                                         selection_end.pos = selection_anchor.pos;
2804
2805                                                         selection_end_anchor = true;
2806                                                 } else {
2807                                                         selection_start.line = selection_anchor.line;
2808                                                         selection_start.pos = selection_anchor.height;
2809                                                         selection_start.tag = selection_anchor.line.FindTag(selection_anchor.height + 1);
2810
2811                                                         selection_end.line = caret.line;
2812                                                         selection_end.tag = caret.line.tags;
2813                                                         selection_end.pos = caret.line.text.Length;
2814
2815                                                         selection_end_anchor = false;
2816                                                 }
2817                                                 selection_prev.line = caret.line;
2818                                                 selection_prev.tag = caret.tag;
2819                                                 selection_prev.pos = caret.pos;
2820
2821                                                 break;
2822                                         }
2823
2824                                         case CaretSelection.Word: {
2825                                                 int     start_pos;
2826                                                 int     end_pos;
2827
2828                                                 start_pos = FindWordSeparator(caret.line, caret.pos, false);
2829                                                 end_pos = FindWordSeparator(caret.line, caret.pos, true);
2830
2831
2832                                                 // Invalidate the selection delta
2833                                                 if (caret > selection_prev) {
2834                                                         Invalidate(selection_prev.line, selection_prev.pos, caret.line, end_pos);
2835                                                 } else {
2836                                                         Invalidate(selection_prev.line, selection_prev.pos, caret.line, start_pos);
2837                                                 }
2838                                                 if (caret < selection_anchor) {
2839                                                         selection_start.line = caret.line;
2840                                                         selection_start.tag = caret.line.FindTag(start_pos + 1);
2841                                                         selection_start.pos = start_pos;
2842
2843                                                         selection_end.line = selection_anchor.line;
2844                                                         selection_end.tag = selection_anchor.tag;
2845                                                         selection_end.pos = selection_anchor.pos;
2846
2847                                                         selection_prev.line = caret.line;
2848                                                         selection_prev.tag = caret.tag;
2849                                                         selection_prev.pos = start_pos;
2850
2851                                                         selection_end_anchor = true;
2852                                                 } else {
2853                                                         selection_start.line = selection_anchor.line;
2854                                                         selection_start.pos = selection_anchor.height;
2855                                                         selection_start.tag = selection_anchor.line.FindTag(selection_anchor.height + 1);
2856
2857                                                         selection_end.line = caret.line;
2858                                                         selection_end.tag = caret.line.FindTag(end_pos);
2859                                                         selection_end.pos = end_pos;
2860
2861                                                         selection_prev.line = caret.line;
2862                                                         selection_prev.tag = caret.tag;
2863                                                         selection_prev.pos = end_pos;
2864
2865                                                         selection_end_anchor = false;
2866                                                 }
2867                                                 break;
2868                                         }
2869
2870                                         case CaretSelection.Position: {
2871                                                 SetSelectionToCaret(false);
2872                                                 return;
2873                                         }
2874                                 }
2875                         } else {
2876                                 // We're setting the selection 'around' the caret position
2877                                 switch(mode) {
2878                                         case CaretSelection.Line: {
2879                                                 this.Invalidate(caret.line, 0, caret.line, caret.line.text.Length);
2880
2881                                                 selection_start.line = caret.line;
2882                                                 selection_start.tag = caret.line.tags;
2883                                                 selection_start.pos = 0;
2884
2885                                                 selection_end.line = caret.line;
2886                                                 selection_end.pos = caret.line.text.Length;
2887                                                 selection_end.tag = caret.line.FindTag(selection_end.pos);
2888
2889                                                 selection_anchor.line = selection_end.line;
2890                                                 selection_anchor.tag = selection_end.tag;
2891                                                 selection_anchor.pos = selection_end.pos;
2892                                                 selection_anchor.height = 0;
2893
2894                                                 selection_prev.line = caret.line;
2895                                                 selection_prev.tag = caret.tag;
2896                                                 selection_prev.pos = caret.pos;
2897
2898                                                 this.selection_end_anchor = true;
2899
2900                                                 break;
2901                                         }
2902
2903                                         case CaretSelection.Word: {
2904                                                 int     start_pos;
2905                                                 int     end_pos;
2906
2907                                                 start_pos = FindWordSeparator(caret.line, caret.pos, false);
2908                                                 end_pos = FindWordSeparator(caret.line, caret.pos, true);
2909
2910                                                 this.Invalidate(selection_start.line, start_pos, caret.line, end_pos);
2911
2912                                                 selection_start.line = caret.line;
2913                                                 selection_start.tag = caret.line.FindTag(start_pos + 1);
2914                                                 selection_start.pos = start_pos;
2915
2916                                                 selection_end.line = caret.line;
2917                                                 selection_end.tag = caret.line.FindTag(end_pos);
2918                                                 selection_end.pos = end_pos;
2919
2920                                                 selection_anchor.line = selection_end.line;
2921                                                 selection_anchor.tag = selection_end.tag;
2922                                                 selection_anchor.pos = selection_end.pos;
2923                                                 selection_anchor.height = start_pos;
2924
2925                                                 selection_prev.line = caret.line;
2926                                                 selection_prev.tag = caret.tag;
2927                                                 selection_prev.pos = caret.pos;
2928
2929                                                 this.selection_end_anchor = true;
2930
2931                                                 break;
2932                                         }
2933                                 }
2934                         }
2935
2936                         SetSelectionVisible (!(selection_start == selection_end));
2937                 }
2938
2939                 internal void SetSelectionToCaret(bool start) {
2940                         if (start) {
2941                                 // Invalidate old selection; selection is being reset to empty
2942                                 this.Invalidate(selection_start.line, selection_start.pos, selection_end.line, selection_end.pos);
2943
2944                                 selection_start.line = caret.line;
2945                                 selection_start.tag = caret.tag;
2946                                 selection_start.pos = caret.pos;
2947
2948                                 // start always also selects end
2949                                 selection_end.line = caret.line;
2950                                 selection_end.tag = caret.tag;
2951                                 selection_end.pos = caret.pos;
2952
2953                                 selection_anchor.line = caret.line;
2954                                 selection_anchor.tag = caret.tag;
2955                                 selection_anchor.pos = caret.pos;
2956                         } else {
2957                                 // Invalidate from previous end to caret (aka new end)
2958                                 if (selection_end_anchor) {
2959                                         if (selection_start != caret) {
2960                                                 this.Invalidate(selection_start.line, selection_start.pos, caret.line, caret.pos);
2961                                         }
2962                                 } else {
2963                                         if (selection_end != caret) {
2964                                                 this.Invalidate(selection_end.line, selection_end.pos, caret.line, caret.pos);
2965                                         }
2966                                 }
2967
2968                                 if (caret < selection_anchor) {
2969                                         selection_start.line = caret.line;
2970                                         selection_start.tag = caret.tag;
2971                                         selection_start.pos = caret.pos;
2972
2973                                         selection_end.line = selection_anchor.line;
2974                                         selection_end.tag = selection_anchor.tag;
2975                                         selection_end.pos = selection_anchor.pos;
2976
2977                                         selection_end_anchor = true;
2978                                 } else {
2979                                         selection_start.line = selection_anchor.line;
2980                                         selection_start.tag = selection_anchor.tag;
2981                                         selection_start.pos = selection_anchor.pos;
2982
2983                                         selection_end.line = caret.line;
2984                                         selection_end.tag = caret.tag;
2985                                         selection_end.pos = caret.pos;
2986
2987                                         selection_end_anchor = false;
2988                                 }
2989                         }
2990
2991                         SetSelectionVisible (!(selection_start == selection_end));
2992                 }
2993
2994                 internal void SetSelection(Line start, int start_pos, Line end, int end_pos) {
2995                         if (selection_visible) {
2996                                 Invalidate(selection_start.line, selection_start.pos, selection_end.line, selection_end.pos);
2997                         }
2998
2999                         if ((end.line_no < start.line_no) || ((end == start) && (end_pos <= start_pos))) {
3000                                 selection_start.line = end;
3001                                 selection_start.tag = LineTag.FindTag(end, end_pos);
3002                                 selection_start.pos = end_pos;
3003
3004                                 selection_end.line = start;
3005                                 selection_end.tag = LineTag.FindTag(start, start_pos);
3006                                 selection_end.pos = start_pos;
3007
3008                                 selection_end_anchor = true;
3009                         } else {
3010                                 selection_start.line = start;
3011                                 selection_start.tag = LineTag.FindTag(start, start_pos);
3012                                 selection_start.pos = start_pos;
3013
3014                                 selection_end.line = end;
3015                                 selection_end.tag = LineTag.FindTag(end, end_pos);
3016                                 selection_end.pos = end_pos;
3017
3018                                 selection_end_anchor = false;
3019                         }
3020
3021                         selection_anchor.line = start;
3022                         selection_anchor.tag = selection_start.tag;
3023                         selection_anchor.pos = start_pos;
3024
3025                         if (((start == end) && (start_pos == end_pos)) || start == null || end == null) {
3026                                 SetSelectionVisible (false);
3027                         } else {
3028                                 SetSelectionVisible (true);
3029                                 Invalidate(selection_start.line, selection_start.pos, selection_end.line, selection_end.pos);
3030                         }
3031                 }
3032
3033                 internal void SetSelectionStart(Line start, int start_pos, bool invalidate) {
3034                         // Invalidate from the previous to the new start pos
3035                         if (invalidate)
3036                                 Invalidate(selection_start.line, selection_start.pos, start, start_pos);
3037
3038                         selection_start.line = start;
3039                         selection_start.pos = start_pos;
3040                         selection_start.tag = LineTag.FindTag(start, start_pos);
3041
3042                         selection_anchor.line = start;
3043                         selection_anchor.pos = start_pos;
3044                         selection_anchor.tag = selection_start.tag;
3045
3046                         selection_end_anchor = false;
3047
3048
3049                         if ((selection_end.line != selection_start.line) || (selection_end.pos != selection_start.pos)) {
3050                                 SetSelectionVisible (true);
3051                         } else {
3052                                 SetSelectionVisible (false);
3053                         }
3054
3055                         if (invalidate)
3056                                 Invalidate(selection_start.line, selection_start.pos, selection_end.line, selection_end.pos);
3057                 }
3058
3059                 internal void SetSelectionStart(int character_index, bool invalidate) {
3060                         Line    line;
3061                         LineTag tag;
3062                         int     pos;
3063
3064                         if (character_index < 0) {
3065                                 return;
3066                         }
3067
3068                         CharIndexToLineTag(character_index, out line, out tag, out pos);
3069                         SetSelectionStart(line, pos, invalidate);
3070                 }
3071
3072                 internal void SetSelectionEnd(Line end, int end_pos, bool invalidate) {
3073
3074                         if (end == selection_end.line && end_pos == selection_start.pos) {
3075                                 selection_anchor.line = selection_start.line;
3076                                 selection_anchor.tag = selection_start.tag;
3077                                 selection_anchor.pos = selection_start.pos;
3078
3079                                 selection_end.line = selection_start.line;
3080                                 selection_end.tag = selection_start.tag;
3081                                 selection_end.pos = selection_start.pos;
3082
3083                                 selection_end_anchor = false;
3084                         } else if ((end.line_no < selection_anchor.line.line_no) || ((end == selection_anchor.line) && (end_pos <= selection_anchor.pos))) {
3085                                 selection_start.line = end;
3086                                 selection_start.tag = LineTag.FindTag(end, end_pos);
3087                                 selection_start.pos = end_pos;
3088
3089                                 selection_end.line = selection_anchor.line;
3090                                 selection_end.tag = selection_anchor.tag;
3091                                 selection_end.pos = selection_anchor.pos;
3092
3093                                 selection_end_anchor = true;
3094                         } else {
3095                                 selection_start.line = selection_anchor.line;
3096                                 selection_start.tag = selection_anchor.tag;
3097                                 selection_start.pos = selection_anchor.pos;
3098
3099                                 selection_end.line = end;
3100                                 selection_end.tag = LineTag.FindTag(end, end_pos);
3101                                 selection_end.pos = end_pos;
3102
3103                                 selection_end_anchor = false;
3104                         }
3105
3106                         if ((selection_end.line != selection_start.line) || (selection_end.pos != selection_start.pos)) {
3107                                 SetSelectionVisible (true);
3108                                 if (invalidate)
3109                                         Invalidate(selection_start.line, selection_start.pos, selection_end.line, selection_end.pos);
3110                         } else {
3111                                 SetSelectionVisible (false);
3112                                 // ?? Do I need to invalidate here, tests seem to work without it, but I don't think they should :-s
3113                         }
3114                 }
3115
3116                 internal void SetSelectionEnd(int character_index, bool invalidate) {
3117                         Line    line;
3118                         LineTag tag;
3119                         int     pos;
3120
3121                         if (character_index < 0) {
3122                                 return;
3123                         }
3124
3125                         CharIndexToLineTag(character_index, out line, out tag, out pos);
3126                         SetSelectionEnd(line, pos, invalidate);
3127                 }
3128
3129                 internal void SetSelection(Line start, int start_pos) {
3130                         if (selection_visible) {
3131                                 Invalidate(selection_start.line, selection_start.pos, selection_end.line, selection_end.pos);
3132                         }
3133
3134                         selection_start.line = start;
3135                         selection_start.pos = start_pos;
3136                         selection_start.tag = LineTag.FindTag(start, start_pos);
3137
3138                         selection_end.line = start;
3139                         selection_end.tag = selection_start.tag;
3140                         selection_end.pos = start_pos;
3141
3142                         selection_anchor.line = start;
3143                         selection_anchor.tag = selection_start.tag;
3144                         selection_anchor.pos = start_pos;
3145
3146                         selection_end_anchor = false;
3147                         SetSelectionVisible (false);
3148                 }
3149
3150                 internal void InvalidateSelectionArea() {
3151                         Invalidate (selection_start.line, selection_start.pos, selection_end.line, selection_end.pos);
3152                 }
3153
3154                 // Return the current selection, as string
3155                 internal string GetSelection() {
3156                         // We return String.Empty if there is no selection
3157                         if ((selection_start.pos == selection_end.pos) && (selection_start.line == selection_end.line)) {
3158                                 return string.Empty;
3159                         }
3160
3161                         if (selection_start.line == selection_end.line) {
3162                                 return selection_start.line.text.ToString (selection_start.pos, selection_end.pos - selection_start.pos);
3163                         } else {
3164                                 StringBuilder   sb;
3165                                 int             i;
3166                                 int             start;
3167                                 int             end;
3168
3169                                 sb = new StringBuilder();
3170                                 start = selection_start.line.line_no;
3171                                 end = selection_end.line.line_no;
3172
3173                                 sb.Append(selection_start.line.text.ToString(selection_start.pos, selection_start.line.text.Length - selection_start.pos));
3174
3175                                 if ((start + 1) < end) {
3176                                         for (i = start + 1; i < end; i++) {
3177                                                 sb.Append(GetLine(i).text.ToString());
3178                                         }
3179                                 }
3180
3181                                 sb.Append(selection_end.line.text.ToString(0, selection_end.pos));
3182
3183                                 return sb.ToString();
3184                         }
3185                 }
3186
3187                 internal void ReplaceSelection(string s, bool select_new) {
3188                         int             i;
3189
3190                         int selection_start_pos = LineTagToCharIndex (selection_start.line, selection_start.pos);
3191                         SuspendRecalc ();
3192
3193                         // First, delete any selected text
3194                         if ((selection_start.pos != selection_end.pos) || (selection_start.line != selection_end.line)) {
3195                                 if (selection_start.line == selection_end.line) {
3196                                         undo.RecordDeleteString (selection_start.line, selection_start.pos, selection_end.line, selection_end.pos);
3197
3198                                         DeleteChars (selection_start.line, selection_start.pos, selection_end.pos - selection_start.pos);
3199
3200                                         // The tag might have been removed, we need to recalc it
3201                                         selection_start.tag = selection_start.line.FindTag(selection_start.pos + 1);
3202                                 } else {
3203                                         int             start;
3204                                         int             end;
3205
3206                                         start = selection_start.line.line_no;
3207                                         end = selection_end.line.line_no;
3208
3209                                         undo.RecordDeleteString (selection_start.line, selection_start.pos, selection_end.line, selection_end.pos);
3210
3211                                         InvalidateLinesAfter(selection_start.line);
3212
3213                                         // Delete first line
3214                                         DeleteChars (selection_start.line, selection_start.pos, selection_start.line.text.Length - selection_start.pos);
3215                                         selection_start.line.recalc = true;
3216
3217                                         // Delete last line
3218                                         DeleteChars(selection_end.line, 0, selection_end.pos);
3219
3220                                         start++;
3221                                         if (start < end) {
3222                                                 for (i = end - 1; i >= start; i--) {
3223                                                         Delete(i);
3224                                                 }
3225                                         }
3226
3227                                         // BIG FAT WARNING - selection_end.line might be stale due
3228                                         // to the above Delete() call. DONT USE IT before hitting the end of this method!
3229
3230                                         // Join start and end
3231                                         Combine(selection_start.line.line_no, start);
3232                                 }
3233                         }
3234
3235
3236                         Insert(selection_start.line, selection_start.pos, false, s);
3237                         undo.RecordInsertString (selection_start.line, selection_start.pos, s);
3238                         ResumeRecalc (false);
3239
3240                         Line begin_update_line = selection_start.line;
3241                         int begin_update_pos = selection_start.pos;
3242
3243                         if (!select_new) {
3244                                 CharIndexToLineTag(selection_start_pos + s.Length, out selection_start.line,
3245                                                 out selection_start.tag, out selection_start.pos);
3246
3247                                 selection_end.line = selection_start.line;
3248                                 selection_end.pos = selection_start.pos;
3249                                 selection_end.tag = selection_start.tag;
3250                                 selection_anchor.line = selection_start.line;
3251                                 selection_anchor.pos = selection_start.pos;
3252                                 selection_anchor.tag = selection_start.tag;
3253
3254                                 SetSelectionVisible (false);
3255                         } else {
3256                                 CharIndexToLineTag(selection_start_pos, out selection_start.line,
3257                                                 out selection_start.tag, out selection_start.pos);
3258
3259                                 CharIndexToLineTag(selection_start_pos + s.Length, out selection_end.line,
3260                                                 out selection_end.tag, out selection_end.pos);
3261
3262                                 selection_anchor.line = selection_start.line;
3263                                 selection_anchor.pos = selection_start.pos;
3264                                 selection_anchor.tag = selection_start.tag;
3265
3266                                 SetSelectionVisible (true);
3267                         }
3268
3269                         PositionCaret (selection_start.line, selection_start.pos);
3270                         UpdateView (begin_update_line, selection_end.line.line_no - begin_update_line.line_no, begin_update_pos);
3271                 }
3272
3273                 internal void CharIndexToLineTag(int index, out Line line_out, out LineTag tag_out, out int pos) {
3274                         Line    line;
3275                         LineTag tag;
3276                         int     i;
3277                         int     chars;
3278                         int     start;
3279
3280                         chars = 0;
3281
3282                         for (i = 1; i <= lines; i++) {
3283                                 line = GetLine(i);
3284
3285                                 start = chars;
3286                                 chars += line.text.Length;
3287
3288                                 if (index <= chars) {
3289                                         // we found the line
3290                                         tag = line.tags;
3291
3292                                         while (tag != null) {
3293                                                 if (index < (start + tag.Start + tag.Length - 1)) {
3294                                                         line_out = line;
3295                                                         tag_out = LineTag.GetFinalTag (tag);
3296                                                         pos = index - start;
3297                                                         return;
3298                                                 }
3299                                                 if (tag.Next == null) {
3300                                                         Line    next_line;
3301
3302                                                         next_line = GetLine(line.line_no + 1);
3303
3304                                                         if (next_line != null) {
3305                                                                 line_out = next_line;
3306                                                                 tag_out = LineTag.GetFinalTag (next_line.tags);
3307                                                                 pos = 0;
3308                                                                 return;
3309                                                         } else {
3310                                                                 line_out = line;
3311                                                                 tag_out = LineTag.GetFinalTag (tag);
3312                                                                 pos = line_out.text.Length;
3313                                                                 return;
3314                                                         }
3315                                                 }
3316                                                 tag = tag.Next;
3317                                         }
3318                                 }
3319                         }
3320
3321                         line_out = GetLine(lines);
3322                         tag = line_out.tags;
3323                         while (tag.Next != null) {
3324                                 tag = tag.Next;
3325                         }
3326                         tag_out = tag;
3327                         pos = line_out.text.Length;
3328                 }
3329
3330                 internal int LineTagToCharIndex(Line line, int pos) {
3331                         int     i;
3332                         int     length;
3333
3334                         // Count first and last line
3335                         length = 0;
3336
3337                         // Count the lines in the middle
3338
3339                         for (i = 1; i < line.line_no; i++) {
3340                                 length += GetLine(i).text.Length;
3341                         }
3342
3343                         length += pos;
3344
3345                         return length;
3346                 }
3347
3348                 internal int SelectionLength() {
3349                         if ((selection_start.pos == selection_end.pos) && (selection_start.line == selection_end.line)) {
3350                                 return 0;
3351                         }
3352
3353                         if (selection_start.line == selection_end.line) {
3354                                 return selection_end.pos - selection_start.pos;
3355                         } else {
3356                                 int     i;
3357                                 int     start;
3358                                 int     end;
3359                                 int     length;
3360
3361                                 // Count first and last line
3362                                 length = selection_start.line.text.Length - selection_start.pos + selection_end.pos + crlf_size;
3363
3364                                 // Count the lines in the middle
3365                                 start = selection_start.line.line_no + 1;
3366                                 end = selection_end.line.line_no;
3367
3368                                 if (start < end) {
3369                                         for (i = start; i < end; i++) {
3370                                                 Line line = GetLine (i);
3371                                                 length += line.text.Length + LineEndingLength (line.ending);
3372                                         }
3373                                 }
3374
3375                                 return length;
3376                         }
3377
3378
3379                 }
3380
3381
3382                 // UIA: Method used via reflection in TextRangeProvider
3383
3384                 /// <summary>Give it a Line number and it returns the Line object at with that line number</summary>
3385                 internal Line GetLine(int LineNo) {
3386                         Line    line = document;
3387
3388                         while (line != sentinel) {
3389                                 if (LineNo == line.line_no) {
3390                                         return line;
3391                                 } else if (LineNo < line.line_no) {
3392                                         line = line.left;
3393                                 } else {
3394                                         line = line.right;
3395                                 }
3396                         }
3397
3398                         return null;
3399                 }
3400
3401                 /// <summary>Retrieve the previous tag; walks line boundaries</summary>
3402                 internal LineTag PreviousTag(LineTag tag) {
3403                         Line l;
3404
3405                         if (tag.Previous != null) {
3406                                 return tag.Previous;
3407                         }
3408
3409                         // Next line
3410                         if (tag.Line.line_no == 1) {
3411                                 return null;
3412                         }
3413
3414                         l = GetLine(tag.Line.line_no - 1);
3415                         if (l != null) {
3416                                 LineTag t;
3417
3418                                 t = l.tags;
3419                                 while (t.Next != null) {
3420                                         t = t.Next;
3421                                 }
3422                                 return t;
3423                         }
3424
3425                         return null;
3426                 }
3427
3428                 /// <summary>Retrieve the next tag; walks line boundaries</summary>
3429                 internal LineTag NextTag(LineTag tag) {
3430                         Line l;
3431
3432                         if (tag.Next != null) {
3433                                 return tag.Next;
3434                         }
3435
3436                         // Next line
3437                         l = GetLine(tag.Line.line_no + 1);
3438                         if (l != null) {
3439                                 return l.tags;
3440                         }
3441
3442                         return null;
3443                 }
3444
3445                 internal Line ParagraphStart(Line line) {
3446                         Line lastline = line;
3447                         do {
3448                                 if (line.line_no <= 1)
3449                                         break;
3450
3451                                 line = lastline;
3452                                 lastline = GetLine (line.line_no - 1);
3453                         } while (lastline.ending == LineEnding.Wrap);
3454
3455                         return line;
3456                 }
3457
3458                 internal Line ParagraphEnd(Line line) {
3459                         Line    l;
3460
3461                         while (line.ending == LineEnding.Wrap) {
3462                                 l = GetLine(line.line_no + 1);
3463                                 if ((l == null) || (l.ending != LineEnding.Wrap)) {
3464                                         break;
3465                                 }
3466                                 line = l;
3467                         }
3468                         return line;
3469                 }
3470
3471                 /// <summary>Give it a pixel offset coordinate and it returns the Line covering that are (offset
3472                 /// is either X or Y depending on if we are multiline
3473                 /// </summary>
3474                 internal Line GetLineByPixel (int offset, bool exact)
3475                 {
3476                         Line    line = document;
3477                         Line    last = null;
3478
3479                         if (multiline) {
3480                                 while (line != sentinel) {
3481                                         last = line;
3482                                         if ((offset >= line.Y) && (offset < (line.Y+line.height))) {
3483                                                 return line;
3484                                         } else if (offset < line.Y) {
3485                                                 line = line.left;
3486                                         } else {
3487                                                 line = line.right;
3488                                         }
3489                                 }
3490                         } else {
3491                                 while (line != sentinel) {
3492                                         last = line;
3493                                         if ((offset >= line.X) && (offset < (line.X + line.Width)))
3494                                                 return line;
3495                                         else if (offset < line.X)
3496                                                 line = line.left;
3497                                         else
3498                                                 line = line.right;
3499                                 }
3500                         }
3501
3502                         if (exact) {
3503                                 return null;
3504                         }
3505                         return last;
3506                 }
3507
3508                 // UIA: Method used via reflection in TextProviderBehavior
3509
3510                 // Give it x/y pixel coordinates and it returns the Tag at that position
3511                 internal LineTag FindCursor (int x, int y, out int index)
3512                 {
3513                         Line line;
3514
3515                         x -= offset_x;
3516                         y -= offset_y;
3517
3518                         line = GetLineByPixel (multiline ? y : x, false);
3519
3520                         LineTag tag = line.GetTag (x);
3521
3522                         if (tag.Length == 0 && tag.Start == 1)
3523                                 index = 0;
3524                         else
3525                                 index = tag.GetCharIndex (x - line.align_shift);
3526
3527                         return tag;
3528                 }
3529
3530                 /// <summary>Format area of document in specified font and color</summary>
3531                 /// <param name="start_pos">1-based start position on start_line</param>
3532                 /// <param name="end_pos">1-based end position on end_line </param>
3533                 internal void FormatText (Line start_line, int start_pos, Line end_line, int end_pos, Font font,
3534                                 Color color, Color back_color, FormatSpecified specified)
3535                 {
3536                         Line    l;
3537
3538                         // First, format the first line
3539                         if (start_line != end_line) {
3540                                 // First line
3541                                 LineTag.FormatText(start_line, start_pos, start_line.text.Length - start_pos + 1, font, color, back_color, specified);
3542
3543                                 // Format last line
3544                                 LineTag.FormatText(end_line, 1, end_pos, font, color, back_color, specified);
3545
3546                                 // Now all the lines inbetween
3547                                 for (int i = start_line.line_no + 1; i < end_line.line_no; i++) {
3548                                         l = GetLine(i);
3549                                         LineTag.FormatText(l, 1, l.text.Length, font, color, back_color, specified);
3550                                 }
3551                         } else {
3552                                 // Special case, single line
3553                                 LineTag.FormatText(start_line, start_pos, end_pos - start_pos, font, color, back_color, specified);
3554
3555                                 if ((end_pos - start_pos) == 0 && CaretTag.Length != 0)
3556                                         CaretTag = CaretTag.Next;
3557                         }
3558                 }
3559
3560                 internal void RecalculateAlignments ()
3561                 {
3562                         Line    line;
3563                         int     line_no;
3564
3565                         line_no = 1;
3566
3567
3568
3569                         while (line_no <= lines) {
3570                                 line = GetLine(line_no);
3571
3572                                 if (line != null) {
3573                                         switch (line.alignment) {
3574                                         case HorizontalAlignment.Left:
3575                                                 line.align_shift = 0;
3576                                                 break;
3577                                         case HorizontalAlignment.Center:
3578                                                 line.align_shift = (viewport_width - (int)line.widths[line.text.Length]) / 2;
3579                                                 break;
3580                                         case HorizontalAlignment.Right:
3581                                                 line.align_shift = viewport_width - (int)line.widths[line.text.Length] - right_margin;
3582                                                 break;
3583                                         }
3584                                 }
3585
3586                                 line_no++;
3587                         }
3588                         return;
3589                 }
3590
3591                 /// <summary>Calculate formatting for the whole document</summary>
3592                 internal bool RecalculateDocument(Graphics g) {
3593                         return RecalculateDocument(g, 1, this.lines, false);
3594                 }
3595
3596                 /// <summary>Calculate formatting starting at a certain line</summary>
3597                 internal bool RecalculateDocument(Graphics g, int start) {
3598                         return RecalculateDocument(g, start, this.lines, false);
3599                 }
3600
3601                 /// <summary>Calculate formatting within two given line numbers</summary>
3602                 internal bool RecalculateDocument(Graphics g, int start, int end) {
3603                         return RecalculateDocument(g, start, end, false);
3604                 }
3605
3606                 /// <summary>With optimize on, returns true if line heights changed</summary>
3607                 internal bool RecalculateDocument(Graphics g, int start, int end, bool optimize) {
3608                         Line    line;
3609                         int     line_no;
3610                         int     offset;
3611                         int     new_width;
3612                         bool    changed;
3613                         int     shift;
3614
3615                         if (recalc_suspended > 0) {
3616                                 recalc_pending = true;
3617                                 recalc_start = Math.Min (recalc_start, start);
3618                                 recalc_end = Math.Max (recalc_end, end);
3619                                 recalc_optimize = optimize;
3620                                 return false;
3621                         }
3622
3623                         // Fixup the positions, they can go kinda nuts
3624                         // (this is suspend and resume recalc - they set them to 1 and max)
3625                         start = Math.Max (start, 1);
3626                         end = Math.Min (end, lines);
3627
3628                         offset = GetLine(start).offset;
3629                         line_no = start;
3630                         new_width = 0;
3631                         shift = this.lines;
3632                         if (!optimize) {
3633                                 changed = true;         // We always return true if we run non-optimized
3634                         } else {
3635                                 changed = false;
3636                         }
3637
3638                         while (line_no <= (end + this.lines - shift)) {
3639                                 line = GetLine(line_no++);
3640                                 line.offset = offset;
3641
3642                                 // if we are not calculating a password
3643                                 if (!calc_pass) {
3644                                         if (!optimize) {
3645                                                 line.RecalculateLine(g, this);
3646                                         } else {
3647                                                 if (line.recalc && line.RecalculateLine(g, this)) {
3648                                                         changed = true;
3649                                                         // If the height changed, all subsequent lines change
3650                                                         end = this.lines;
3651                                                         shift = this.lines;
3652                                                 }
3653                                         }
3654                                 } else {
3655                                         if (!optimize) {
3656                                                 line.RecalculatePasswordLine(g, this);
3657                                         } else {
3658                                                 if (line.recalc && line.RecalculatePasswordLine(g, this)) {
3659                                                         changed = true;
3660                                                         // If the height changed, all subsequent lines change
3661                                                         end = this.lines;
3662                                                         shift = this.lines;
3663                                                 }
3664                                         }
3665                                 }
3666
3667                                 if (line.widths[line.text.Length] > new_width) {
3668                                         new_width = (int)line.widths[line.text.Length];
3669                                 }
3670
3671                                 // Calculate alignment
3672                                 if (line.alignment != HorizontalAlignment.Left) {
3673                                         if (line.alignment == HorizontalAlignment.Center) {
3674                                                 line.align_shift = (viewport_width - (int)line.widths[line.text.Length]) / 2;
3675                                         } else {
3676                                                 line.align_shift = viewport_width - (int)line.widths[line.text.Length] - 1;
3677                                         }
3678                                 }
3679
3680                                 if (multiline)
3681                                         offset += line.height;
3682                                 else
3683                                         offset += (int) line.widths [line.text.Length];
3684
3685                                 if (line_no > lines) {
3686                                         break;
3687                                 }
3688                         }
3689
3690                         if (document_x != new_width) {
3691                                 document_x = new_width;
3692                                 if (WidthChanged != null) {
3693                                         WidthChanged(this, null);
3694                                 }
3695                         }
3696
3697                         RecalculateAlignments();
3698
3699                         line = GetLine(lines);
3700
3701                         if (document_y != line.Y + line.height) {
3702                                 document_y = line.Y + line.height;
3703                                 if (HeightChanged != null) {
3704                                         HeightChanged(this, null);
3705                                 }
3706                         }
3707
3708                         // scan for links and tell us if its all
3709                         // changed, so we can update everything
3710                         if (EnableLinks)
3711                                 ScanForLinks (start, end, ref changed);
3712
3713                         UpdateCaret();
3714                         return changed;
3715                 }
3716
3717                 internal int Size() {
3718                         return lines;
3719                 }
3720
3721                 private void owner_HandleCreated(object sender, EventArgs e) {
3722                         RecalculateDocument(owner.CreateGraphicsInternal());
3723                         AlignCaret();
3724                 }
3725
3726                 private void owner_VisibleChanged(object sender, EventArgs e) {
3727                         if (owner.Visible) {
3728                                 RecalculateDocument(owner.CreateGraphicsInternal());
3729                         }
3730                 }
3731
3732                 internal static bool IsWordSeparator (char ch)
3733                 {
3734                         switch (ch) {
3735                         case ' ':
3736                         case '\t':
3737                         case '(':
3738                         case ')':
3739                         case '\r':
3740                         case '\n':
3741                                 return true;
3742                         default:
3743                                 return false;
3744                         }
3745                 }
3746
3747                 internal int FindWordSeparator(Line line, int pos, bool forward) {
3748                         int len;
3749
3750                         len = line.text.Length;
3751
3752                         if (forward) {
3753                                 for (int i = pos + 1; i < len; i++) {
3754                                         if (IsWordSeparator(line.Text[i])) {
3755                                                 return i + 1;
3756                                         }
3757                                 }
3758                                 return len;
3759                         } else {
3760                                 for (int i = pos - 1; i > 0; i--) {
3761                                         if (IsWordSeparator(line.Text[i - 1])) {
3762                                                 return i;
3763                                         }
3764                                 }
3765                                 return 0;
3766                         }
3767                 }
3768
3769                 /* Search document for text */
3770                 internal bool FindChars(char[] chars, Marker start, Marker end, out Marker result) {
3771                         Line    line;
3772                         int     line_no;
3773                         int     pos;
3774                         int     line_len;
3775
3776                         // Search for occurence of any char in the chars array
3777                         result = new Marker();
3778
3779                         line = start.line;
3780                         line_no = start.line.line_no;
3781                         pos = start.pos;
3782                         while (line_no <= end.line.line_no) {
3783                                 line_len = line.text.Length;
3784                                 while (pos < line_len) {
3785                                         for (int i = 0; i < chars.Length; i++) {
3786                                                 if (line.text[pos] == chars[i]) {
3787                                                         // Special case
3788                                                         if ((line.line_no == end.line.line_no) && (pos >= end.pos)) {
3789                                                                 return false;
3790                                                         }
3791
3792                                                         result.line = line;
3793                                                         result.pos = pos;
3794                                                         return true;
3795                                                 }
3796                                         }
3797                                         pos++;
3798                                 }
3799
3800                                 pos = 0;
3801                                 line_no++;
3802                                 line = GetLine(line_no);
3803                         }
3804
3805                         return false;
3806                 }
3807
3808                 // This version does not build one big string for searching, instead it handles
3809                 // line-boundaries, which is faster and less memory intensive
3810                 // FIXME - Depending on culture stuff we might have to create a big string and use culturespecific
3811                 // search stuff and change it to accept and return positions instead of Markers (which would match
3812                 // RichTextBox behaviour better but would be inconsistent with the rest of TextControl)
3813                 internal bool Find(string search, Marker start, Marker end, out Marker result, RichTextBoxFinds options) {
3814                         Marker  last;
3815                         string  search_string;
3816                         Line    line;
3817                         int     line_no;
3818                         int     pos;
3819                         int     line_len;
3820                         int     current;
3821                         bool    word;
3822                         bool    word_option;
3823                         bool    ignore_case;
3824                         bool    reverse;
3825                         char    c;
3826
3827                         result = new Marker();
3828                         word_option = ((options & RichTextBoxFinds.WholeWord) != 0);
3829                         ignore_case = ((options & RichTextBoxFinds.MatchCase) == 0);
3830                         reverse = ((options & RichTextBoxFinds.Reverse) != 0);
3831
3832                         line = start.line;
3833                         line_no = start.line.line_no;
3834                         pos = start.pos;
3835                         current = 0;
3836
3837                         // Prep our search string, lowercasing it if we do case-independent matching
3838                         if (ignore_case) {
3839                                 StringBuilder   sb;
3840                                 sb = new StringBuilder(search);
3841                                 for (int i = 0; i < sb.Length; i++) {
3842                                         sb[i] = Char.ToLower(sb[i]);
3843                                 }
3844                                 search_string = sb.ToString();
3845                         } else {
3846                                 search_string = search;
3847                         }
3848
3849                         // We need to check if the character before our start position is a wordbreak
3850                         if (word_option) {
3851                                 if (line_no == 1) {
3852                                         if ((pos == 0) || (IsWordSeparator(line.text[pos - 1]))) {
3853                                                 word = true;
3854                                         } else {
3855                                                 word = false;
3856                                         }
3857                                 } else {
3858                                         if (pos > 0) {
3859                                                 if (IsWordSeparator(line.text[pos - 1])) {
3860                                                         word = true;
3861                                                 } else {
3862                                                         word = false;
3863                                                 }
3864                                         } else {
3865                                                 // Need to check the end of the previous line
3866                                                 Line    prev_line;
3867
3868                                                 prev_line = GetLine(line_no - 1);
3869                                                 if (prev_line.ending == LineEnding.Wrap) {
3870                                                         if (IsWordSeparator(prev_line.text[prev_line.text.Length - 1])) {
3871                                                                 word = true;
3872                                                         } else {
3873                                                                 word = false;
3874                                                         }
3875                                                 } else {
3876                                                         word = true;
3877                                                 }
3878                                         }
3879                                 }
3880                         } else {
3881                                 word = false;
3882                         }
3883
3884                         // To avoid duplication of this loop with reverse logic, we search
3885                         // through the document, remembering the last match and when returning
3886                         // report that last remembered match
3887
3888                         last = new Marker();
3889                         last.height = -1;       // Abused - we use it to track change
3890
3891                         while (line_no <= end.line.line_no) {
3892                                 if (line_no != end.line.line_no) {
3893                                         line_len = line.text.Length;
3894                                 } else {
3895                                         line_len = end.pos;
3896                                 }
3897
3898                                 while (pos < line_len) {
3899
3900                                         if (word_option && (current == search_string.Length)) {
3901                                                 if (IsWordSeparator(line.text[pos])) {
3902                                                         if (!reverse) {
3903                                                                 goto FindFound;
3904                                                         } else {
3905                                                                 last = result;
3906                                                                 current = 0;
3907                                                         }
3908                                                 } else {
3909                                                         current = 0;
3910                                                 }
3911                                         }
3912
3913                                         if (ignore_case) {
3914                                                 c = Char.ToLower(line.text[pos]);
3915                                         } else {
3916                                                 c = line.text[pos];
3917                                         }
3918
3919                                         if (c == search_string[current]) {
3920
3921                                                 if (current == 0) {
3922                                                         result.line = line;
3923                                                         result.pos = pos;
3924                                                 }
3925                                                 if (!word_option || (word_option && (word || (current > 0)))) {
3926                                                         current++;
3927                                                 }
3928
3929                                                 if (!word_option && (current == search_string.Length)) {
3930                                                         if (!reverse) {
3931                                                                 goto FindFound;
3932                                                         } else {
3933                                                                 last = result;
3934                                                                 current = 0;
3935                                                         }
3936                                                 }
3937                                         } else {
3938                                                 current = 0;
3939                                         }
3940                                         pos++;
3941
3942                                         if (!word_option) {
3943                                                 continue;
3944                                         }
3945
3946                                         if (IsWordSeparator(c)) {
3947                                                 word = true;
3948                                         } else {
3949                                                 word = false;
3950                                         }
3951                                 }
3952
3953                                 if (word_option) {
3954                                         // Mark that we just saw a word boundary
3955                                         if (line.ending != LineEnding.Wrap || line.line_no == lines - 1) {
3956                                                 word = true;
3957                                         }
3958
3959                                         if (current == search_string.Length) {
3960                                                 if (word) {
3961                                                         if (!reverse) {
3962                                                                 goto FindFound;
3963                                                         } else {
3964                                                                 last = result;
3965                                                                 current = 0;
3966                                                         }
3967                                                 } else {
3968                                                         current = 0;
3969                                                 }
3970                                         }
3971                                 }
3972
3973                                 pos = 0;
3974                                 line_no++;
3975                                 line = GetLine(line_no);
3976                         }
3977
3978                         if (reverse) {
3979                                 if (last.height != -1) {
3980                                         result = last;
3981                                         return true;
3982                                 }
3983                         }
3984
3985                         return false;
3986
3987                         FindFound:
3988                         if (!reverse) {
3989 //                              if ((line.line_no == end.line.line_no) && (pos >= end.pos)) {
3990 //                                      return false;
3991 //                              }
3992                                 return true;
3993                         }
3994
3995                         result = last;
3996                         return true;
3997
3998                 }
3999
4000                 /* Marker stuff */
4001                 internal void GetMarker(out Marker mark, bool start) {
4002                         mark = new Marker();
4003
4004                         if (start) {
4005                                 mark.line = GetLine(1);
4006                                 mark.tag = mark.line.tags;
4007                                 mark.pos = 0;
4008                         } else {
4009                                 mark.line = GetLine(lines);
4010                                 mark.tag = mark.line.tags;
4011                                 while (mark.tag.Next != null) {
4012                                         mark.tag = mark.tag.Next;
4013                                 }
4014                                 mark.pos = mark.line.text.Length;
4015                         }
4016                 }
4017                 #endregion      // Internal Methods
4018
4019                 #region Events
4020                 internal event EventHandler CaretMoved;
4021                 internal event EventHandler WidthChanged;
4022                 internal event EventHandler HeightChanged;
4023                 internal event EventHandler LengthChanged;
4024                 internal event EventHandler UIASelectionChanged;
4025                 #endregion      // Events
4026
4027                 #region Administrative
4028                 public IEnumerator GetEnumerator() {
4029                         // FIXME
4030                         return null;
4031                 }
4032
4033                 public override bool Equals(object obj) {
4034                         if (obj == null) {
4035                                 return false;
4036                         }
4037
4038                         if (!(obj is Document)) {
4039                                 return false;
4040                         }
4041
4042                         if (obj == this) {
4043                                 return true;
4044                         }
4045
4046                         if (ToString().Equals(((Document)obj).ToString())) {
4047                                 return true;
4048                         }
4049
4050                         return false;
4051                 }
4052
4053                 public override int GetHashCode() {
4054                         return document_id;
4055                 }
4056
4057                 public override string ToString() {
4058                         return "document " + this.document_id;
4059                 }
4060                 #endregion      // Administrative
4061         }
4062
4063         internal class PictureTag : LineTag {
4064
4065                 internal RTF.Picture picture;
4066
4067                 internal PictureTag (Line line, int start, RTF.Picture picture) : base (line, start)
4068                 {
4069                         this.picture = picture;
4070                 }
4071
4072                 public override bool IsTextTag {
4073                         get { return false; }
4074                 }
4075
4076                 public override SizeF SizeOfPosition (Graphics dc, int pos)
4077                 {
4078                         return picture.Size;
4079                 }
4080
4081                 internal override int MaxHeight ()
4082                 {
4083                         return (int) (picture.Height + 0.5F);
4084                 }
4085
4086                 public override void Draw (Graphics dc, Color color, float xoff, float y, int start, int end)
4087                 {
4088                         picture.DrawImage (dc, xoff + Line.widths [start], y, false);
4089                 }
4090
4091                 public override void Draw (Graphics dc, Color color, float xoff, float y, int start, int end, string text)
4092                 {
4093                         picture.DrawImage (dc, xoff + + Line.widths [start], y, false);
4094                 }
4095
4096                 public override string Text ()
4097                 {
4098                         return "I";
4099                 }
4100         }
4101
4102         internal class UndoManager {
4103
4104                 internal enum ActionType {
4105
4106                         Typing,
4107
4108                         // This is basically just cut & paste
4109                         InsertString,
4110                         DeleteString,
4111
4112                         UserActionBegin,
4113                         UserActionEnd
4114                 }
4115
4116                 internal class Action {
4117                         internal ActionType     type;
4118                         internal int            line_no;
4119                         internal int            pos;
4120                         internal object         data;
4121                 }
4122
4123                 #region Local Variables
4124                 private Document        document;
4125                 private Stack           undo_actions;
4126                 private Stack           redo_actions;
4127
4128                 //private int           caret_line;
4129                 //private int           caret_pos;
4130
4131                 // When performing an action, we lock the queue, so that the action can't be undone
4132                 private bool locked;
4133                 #endregion      // Local Variables
4134
4135                 #region Constructors
4136                 internal UndoManager (Document document)
4137                 {
4138                         this.document = document;
4139                         undo_actions = new Stack (50);
4140                         redo_actions = new Stack (50);
4141                 }
4142                 #endregion      // Constructors
4143
4144                 #region Properties
4145                 internal bool CanUndo {
4146                         get { return undo_actions.Count > 0; }
4147                 }
4148
4149                 internal bool CanRedo {
4150                         get { return redo_actions.Count > 0; }
4151                 }
4152
4153                 internal string UndoActionName {
4154                         get {
4155                                 foreach (Action action in undo_actions) {
4156                                         if (action.type == ActionType.UserActionBegin)
4157                                                 return (string) action.data;
4158                                         if (action.type == ActionType.Typing)
4159                                                 return Locale.GetText ("Typing");
4160                                 }
4161                                 return String.Empty;
4162                         }
4163                 }
4164
4165                 internal string RedoActionName {
4166                         get {
4167                                 foreach (Action action in redo_actions) {
4168                                         if (action.type == ActionType.UserActionBegin)
4169                                                 return (string) action.data;
4170                                         if (action.type == ActionType.Typing)
4171                                                 return Locale.GetText ("Typing");
4172                                 }
4173                                 return String.Empty;
4174                         }
4175                 }
4176                 #endregion      // Properties
4177
4178                 #region Internal Methods
4179                 internal void Clear ()
4180                 {
4181                         undo_actions.Clear();
4182                         redo_actions.Clear();
4183                 }
4184
4185                 internal bool Undo ()
4186                 {
4187                         Action action;
4188                         bool user_action_finished = false;
4189
4190                         if (undo_actions.Count == 0)
4191                                 return false;
4192
4193                         locked = true;
4194                         do {
4195                                 Line start;
4196                                 action = (Action) undo_actions.Pop ();
4197
4198                                 // Put onto redo stack
4199                                 redo_actions.Push(action);
4200
4201                                 // Do the thing
4202                                 switch(action.type) {
4203
4204                                 case ActionType.UserActionBegin:
4205                                         user_action_finished = true;
4206                                         break;
4207
4208                                 case ActionType.UserActionEnd:
4209                                         // noop
4210                                         break;
4211
4212                                 case ActionType.InsertString:
4213                                         start = document.GetLine (action.line_no);
4214                                         document.SuspendUpdate ();
4215                                         document.DeleteMultiline (start, action.pos, ((string) action.data).Length + 1);
4216                                         document.PositionCaret (start, action.pos);
4217                                         document.SetSelectionToCaret (true);
4218                                         document.ResumeUpdate (true);
4219                                         break;
4220
4221                                 case ActionType.Typing:
4222                                         start = document.GetLine (action.line_no);
4223                                         document.SuspendUpdate ();
4224                                         document.DeleteMultiline (start, action.pos, ((StringBuilder) action.data).Length);
4225                                         document.PositionCaret (start, action.pos);
4226                                         document.SetSelectionToCaret (true);
4227                                         document.ResumeUpdate (true);
4228
4229                                         // This is an open ended operation, so only a single typing operation can be undone at once
4230                                         user_action_finished = true;
4231                                         break;
4232
4233                                 case ActionType.DeleteString:
4234                                         start = document.GetLine (action.line_no);
4235                                         document.SuspendUpdate ();
4236                                         Insert (start, action.pos, (Line) action.data, true);
4237                                         document.ResumeUpdate (true);
4238                                         break;
4239                                 }
4240                         } while (!user_action_finished && undo_actions.Count > 0);
4241
4242                         locked = false;
4243
4244                         return true;
4245                 }
4246
4247                 internal bool Redo ()
4248                 {
4249                         Action action;
4250                         bool user_action_finished = false;
4251
4252                         if (redo_actions.Count == 0)
4253                                 return false;
4254
4255                         locked = true;
4256                         do {
4257                                 Line start;
4258                                 int start_index;
4259
4260                                 action = (Action) redo_actions.Pop ();
4261                                 undo_actions.Push (action);
4262
4263                                 switch (action.type) {
4264
4265                                 case ActionType.UserActionBegin:
4266                                         //  Noop
4267                                         break;
4268
4269                                 case ActionType.UserActionEnd:
4270                                         user_action_finished = true;
4271                                         break;
4272
4273                                 case ActionType.InsertString:
4274                                         start = document.GetLine (action.line_no);
4275                                         document.SuspendUpdate ();
4276                                         start_index = document.LineTagToCharIndex (start, action.pos);
4277                                         document.InsertString (start, action.pos, (string) action.data);
4278                                         document.CharIndexToLineTag (start_index + ((string) action.data).Length,
4279                                                         out document.caret.line, out document.caret.tag,
4280                                                         out document.caret.pos);
4281                                         document.UpdateCaret ();
4282                                         document.SetSelectionToCaret (true);
4283                                         document.ResumeUpdate (true);
4284                                         break;
4285
4286                                 case ActionType.Typing:
4287                                         start = document.GetLine (action.line_no);
4288                                         document.SuspendUpdate ();
4289                                         start_index = document.LineTagToCharIndex (start, action.pos);
4290                                         document.InsertString (start, action.pos, ((StringBuilder) action.data).ToString ());
4291                                         document.CharIndexToLineTag (start_index + ((StringBuilder) action.data).Length,
4292                                                         out document.caret.line, out document.caret.tag,
4293                                                         out document.caret.pos);
4294                                         document.UpdateCaret ();
4295                                         document.SetSelectionToCaret (true);
4296                                         document.ResumeUpdate (true);
4297
4298                                         // This is an open ended operation, so only a single typing operation can be undone at once
4299                                         user_action_finished = true;
4300                                         break;
4301
4302                                 case ActionType.DeleteString:
4303                                         start = document.GetLine (action.line_no);
4304                                         document.SuspendUpdate ();
4305                                         document.DeleteMultiline (start, action.pos, ((Line) action.data).text.Length);
4306                                         document.PositionCaret (start, action.pos);
4307                                         document.SetSelectionToCaret (true);
4308                                         document.ResumeUpdate (true);
4309
4310                                         break;
4311                                 }
4312                         } while (!user_action_finished && redo_actions.Count > 0);
4313
4314                         locked = false;
4315
4316                         return true;
4317                 }
4318                 #endregion      // Internal Methods
4319
4320                 #region Private Methods
4321
4322                 public void BeginUserAction (string name)
4323                 {
4324                         if (locked)
4325                                 return;
4326
4327                         // Nuke the redo queue
4328                         redo_actions.Clear ();
4329
4330                         Action ua = new Action ();
4331                         ua.type = ActionType.UserActionBegin;
4332                         ua.data = name;
4333
4334                         undo_actions.Push (ua);
4335                 }
4336
4337                 public void EndUserAction ()
4338                 {
4339                         if (locked)
4340                                 return;
4341
4342                         Action ua = new Action ();
4343                         ua.type = ActionType.UserActionEnd;
4344
4345                         undo_actions.Push (ua);
4346                 }
4347
4348                 // start_pos, end_pos = 1 based
4349                 public void RecordDeleteString (Line start_line, int start_pos, Line end_line, int end_pos)
4350                 {
4351                         if (locked)
4352                                 return;
4353
4354                         // Nuke the redo queue
4355                         redo_actions.Clear ();
4356
4357                         Action  a = new Action ();
4358
4359                         // We cant simply store the string, because then formatting would be lost
4360                         a.type = ActionType.DeleteString;
4361                         a.line_no = start_line.line_no;
4362                         a.pos = start_pos;
4363                         a.data = Duplicate (start_line, start_pos, end_line, end_pos);
4364
4365                         undo_actions.Push(a);
4366                 }
4367
4368                 public void RecordInsertString (Line line, int pos, string str)
4369                 {
4370                         if (locked || str.Length == 0)
4371                                 return;
4372
4373                         // Nuke the redo queue
4374                         redo_actions.Clear ();
4375
4376                         Action a = new Action ();
4377
4378                         a.type = ActionType.InsertString;
4379                         a.data = str;
4380                         a.line_no = line.line_no;
4381                         a.pos = pos;
4382
4383                         undo_actions.Push (a);
4384                 }
4385
4386                 public void RecordTyping (Line line, int pos, char ch)
4387                 {
4388                         if (locked)
4389                                 return;
4390
4391                         // Nuke the redo queue
4392                         redo_actions.Clear ();
4393
4394                         Action a = null;
4395
4396                         if (undo_actions.Count > 0)
4397                                 a = (Action) undo_actions.Peek ();
4398
4399                         if (a == null || a.type != ActionType.Typing) {
4400                                 a = new Action ();
4401                                 a.type = ActionType.Typing;
4402                                 a.data = new StringBuilder ();
4403                                 a.line_no = line.line_no;
4404                                 a.pos = pos;
4405
4406                                 undo_actions.Push (a);
4407                         }
4408
4409                         StringBuilder data = (StringBuilder) a.data;
4410                         data.Append (ch);
4411                 }
4412
4413                 // start_pos = 1-based
4414                 // end_pos = 1-based
4415                 public Line Duplicate(Line start_line, int start_pos, Line end_line, int end_pos)
4416                 {
4417                         Line    ret;
4418                         Line    line;
4419                         Line    current;
4420                         LineTag tag;
4421                         LineTag current_tag;
4422                         int     start;
4423                         int     end;
4424                         int     tag_start;
4425
4426                         line = new Line (start_line.document, start_line.ending);
4427                         ret = line;
4428
4429                         for (int i = start_line.line_no; i <= end_line.line_no; i++) {
4430                                 current = document.GetLine(i);
4431
4432                                 if (start_line.line_no == i) {
4433                                         start = start_pos;
4434                                 } else {
4435                                         start = 0;
4436                                 }
4437
4438                                 if (end_line.line_no == i) {
4439                                         end = end_pos;
4440                                 } else {
4441                                         end = current.text.Length;
4442                                 }
4443
4444                                 if (end_pos == 0)
4445                                         continue;
4446
4447                                 // Text for the tag
4448                                 line.text = new StringBuilder (current.text.ToString (start, end - start));
4449
4450                                 // Copy tags from start to start+length onto new line
4451                                 current_tag = current.FindTag (start + 1);
4452                                 while ((current_tag != null) && (current_tag.Start <= end)) {
4453                                         if ((current_tag.Start <= start) && (start < (current_tag.Start + current_tag.Length))) {
4454                                                 // start tag is within this tag
4455                                                 tag_start = start;
4456                                         } else {
4457                                                 tag_start = current_tag.Start;
4458                                         }
4459
4460                                         tag = new LineTag(line, tag_start - start + 1);
4461                                         tag.CopyFormattingFrom (current_tag);
4462
4463                                         current_tag = current_tag.Next;
4464
4465                                         // Add the new tag to the line
4466                                         if (line.tags == null) {
4467                                                 line.tags = tag;
4468                                         } else {
4469                                                 LineTag tail;
4470                                                 tail = line.tags;
4471
4472                                                 while (tail.Next != null) {
4473                                                         tail = tail.Next;
4474                                                 }
4475                                                 tail.Next = tag;
4476                                                 tag.Previous = tail;
4477                                         }
4478                                 }
4479
4480                                 if ((i + 1) <= end_line.line_no) {
4481                                         line.ending = current.ending;
4482
4483                                         // Chain them (we use right/left as next/previous)
4484                                         line.right = new Line (start_line.document, start_line.ending);
4485                                         line.right.left = line;
4486                                         line = line.right;
4487                                 }
4488                         }
4489
4490                         return ret;
4491                 }
4492
4493                 // Insert multi-line text at the given position; use formatting at insertion point for inserted text
4494                 internal void Insert(Line line, int pos, Line insert, bool select)
4495                 {
4496                         Line    current;
4497                         LineTag tag;
4498                         int     offset;
4499                         int     lines;
4500                         Line    first;
4501
4502                         // Handle special case first
4503                         if (insert.right == null) {
4504
4505                                 // Single line insert
4506                                 document.Split(line, pos);
4507
4508                                 if (insert.tags == null) {
4509                                         return; // Blank line
4510                                 }
4511
4512                                 //Insert our tags at the end
4513                                 tag = line.tags;
4514
4515                                 while (tag.Next != null) {
4516                                         tag = tag.Next;
4517                                 }
4518
4519                                 offset = tag.Start + tag.Length - 1;
4520
4521                                 tag.Next = insert.tags;
4522                                 line.text.Insert(offset, insert.text.ToString());
4523
4524                                 // Adjust start locations
4525                                 tag = tag.Next;
4526                                 while (tag != null) {
4527                                         tag.Start += offset;
4528                                         tag.Line = line;
4529                                         tag = tag.Next;
4530                                 }
4531                                 // Put it back together
4532                                 document.Combine(line.line_no, line.line_no + 1);
4533
4534                                 if (select) {
4535                                         document.SetSelectionStart (line, pos, false);
4536                                         document.SetSelectionEnd (line, pos + insert.text.Length, false);
4537                                 }
4538
4539                                 document.UpdateView(line, pos);
4540                                 return;
4541                         }
4542
4543                         first = line;
4544                         lines = 1;
4545                         current = insert;
4546
4547                         while (current != null) {
4548
4549                                 if (current == insert) {
4550                                         // Inserting the first line we split the line (and make space)
4551                                         document.Split(line.line_no, pos);
4552                                         //Insert our tags at the end of the line
4553                                         tag = line.tags;
4554
4555
4556                                         if (tag != null && tag.Length != 0) {
4557                                                 while (tag.Next != null) {
4558                                                         tag = tag.Next;
4559                                                 }
4560                                                 offset = tag.Start + tag.Length - 1;
4561                                                 tag.Next = current.tags;
4562                                                 tag.Next.Previous = tag;
4563
4564                                                 tag = tag.Next;
4565
4566                                         } else {
4567                                                 offset = 0;
4568                                                 line.tags = current.tags;
4569                                                 line.tags.Previous = null;
4570                                                 tag = line.tags;
4571                                         }
4572
4573                                         line.ending = current.ending;
4574                                 } else {
4575                                         document.Split(line.line_no, 0);
4576                                         offset = 0;
4577                                         line.tags = current.tags;
4578                                         line.tags.Previous = null;
4579                                         line.ending = current.ending;
4580                                         tag = line.tags;
4581                                 }
4582
4583                                 // Adjust start locations and line pointers
4584                                 while (tag != null) {
4585                                         tag.Start += offset - 1;
4586                                         tag.Line = line;
4587                                         tag = tag.Next;
4588                                 }
4589
4590                                 line.text.Insert(offset, current.text.ToString());
4591                                 line.Grow(line.text.Length);
4592
4593                                 line.recalc = true;
4594                                 line = document.GetLine(line.line_no + 1);
4595
4596                                 // FIXME? Test undo of line-boundaries
4597                                 if ((current.right == null) && (current.tags.Length != 0)) {
4598                                         document.Combine(line.line_no - 1, line.line_no);
4599                                 }
4600                                 current = current.right;
4601                                 lines++;
4602
4603                         }
4604
4605                         // Recalculate our document
4606                         document.UpdateView(first, lines, pos);
4607                         return;
4608                 }
4609                 #endregion      // Private Methods
4610         }
4611 }