gcc/ada/a-ciorse.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT LIBRARY COMPONENTS                          --
   4 --                                                                          --
   5 --                      A D A . C O N T A I N E R S .                       --
   6 --              I N D E F I N I T E _ O R D E R E D _ S E T S               --
   7 --                                                                          --
   8 --                                 B o d y                                  --
   9 --                                                                          --
  10 --          Copyright (C) 2004-2006, Free Software Foundation, Inc.         --
  11 --                                                                          --
  12 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  13 -- terms of the  GNU General Public License as published  by the Free Soft- --
  14 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  15 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  16 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  17 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  18 -- for  more details.  You should have  received  a copy of the GNU General --
  19 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  20 -- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
  21 -- Boston, MA 02110-1301, USA.                                              --
  22 --                                                                          --
  23 -- As a special exception,  if other files  instantiate  generics from this --
  24 -- unit, or you link  this unit with other files  to produce an executable, --
  25 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  26 -- covered  by the  GNU  General  Public  License.  This exception does not --
  27 -- however invalidate  any other reasons why  the executable file  might be --
  28 -- covered by the  GNU Public License.                                      --
  29 --                                                                          --
  30 -- This unit was originally developed by Matthew J Heaney.                  --
  31 ------------------------------------------------------------------------------
  32
  33 with Ada.Containers.Red_Black_Trees.Generic_Operations;
  34 pragma Elaborate_All (Ada.Containers.Red_Black_Trees.Generic_Operations);
  35
  36 with Ada.Containers.Red_Black_Trees.Generic_Keys;
  37 pragma Elaborate_All (Ada.Containers.Red_Black_Trees.Generic_Keys);
  38
  39 with Ada.Containers.Red_Black_Trees.Generic_Set_Operations;
  40 pragma Elaborate_All (Ada.Containers.Red_Black_Trees.Generic_Set_Operations);
  41
  42 with Ada.Unchecked_Deallocation;
  43
  44 package body Ada.Containers.Indefinite_Ordered_Sets is
  45
  46    -----------------------
  47    -- Local Subprograms --
  48    -----------------------
  49
  50    function Color (Node : Node_Access) return Color_Type;
  51    pragma Inline (Color);
  52
  53    function Copy_Node (Source : Node_Access) return Node_Access;
  54    pragma Inline (Copy_Node);
  55
  56    procedure Free (X : in out Node_Access);
  57
  58    procedure Insert_Sans_Hint
  59      (Tree     : in out Tree_Type;
  60       New_Item : Element_Type;
  61       Node     : out Node_Access;
  62       Inserted : out Boolean);
  63
  64    procedure Insert_With_Hint
  65      (Dst_Tree : in out Tree_Type;
  66       Dst_Hint : Node_Access;
  67       Src_Node : Node_Access;
  68       Dst_Node : out Node_Access);
  69
  70    function Is_Greater_Element_Node
  71      (Left  : Element_Type;
  72       Right : Node_Access) return Boolean;
  73    pragma Inline (Is_Greater_Element_Node);
  74
  75    function Is_Less_Element_Node
  76      (Left  : Element_Type;
  77       Right : Node_Access) return Boolean;
  78    pragma Inline (Is_Less_Element_Node);
  79
  80    function Is_Less_Node_Node (L, R : Node_Access) return Boolean;
  81    pragma Inline (Is_Less_Node_Node);
  82
  83    function Left (Node : Node_Access) return Node_Access;
  84    pragma Inline (Left);
  85
  86    function Parent (Node : Node_Access) return Node_Access;
  87    pragma Inline (Parent);
  88
  89    procedure Replace_Element
  90      (Tree : in out Tree_Type;
  91       Node : Node_Access;
  92       Item : Element_Type);
  93
  94    function Right (Node : Node_Access) return Node_Access;
  95    pragma Inline (Right);
  96
  97    procedure Set_Color (Node : Node_Access; Color : Color_Type);
  98    pragma Inline (Set_Color);
  99
 100    procedure Set_Left (Node : Node_Access; Left : Node_Access);
 101    pragma Inline (Set_Left);
 102
 103    procedure Set_Parent (Node   : Node_Access; Parent : Node_Access);
 104    pragma Inline (Set_Parent);
 105
 106    procedure Set_Right (Node : Node_Access; Right : Node_Access);
 107    pragma Inline (Set_Right);
 108
 109    --------------------------
 110    -- Local Instantiations --
 111    --------------------------
 112
 113    procedure Free_Element is
 114      new Ada.Unchecked_Deallocation (Element_Type, Element_Access);
 115
 116    package Tree_Operations is
 117      new Red_Black_Trees.Generic_Operations (Tree_Types);
 118
 119    procedure Delete_Tree is
 120      new Tree_Operations.Generic_Delete_Tree (Free);
 121
 122    function Copy_Tree is
 123      new Tree_Operations.Generic_Copy_Tree (Copy_Node, Delete_Tree);
 124
 125    use Tree_Operations;
 126
 127    package Element_Keys is
 128      new Red_Black_Trees.Generic_Keys
 129        (Tree_Operations     => Tree_Operations,
 130         Key_Type            => Element_Type,
 131         Is_Less_Key_Node    => Is_Less_Element_Node,
 132         Is_Greater_Key_Node => Is_Greater_Element_Node);
 133
 134    package Set_Ops is
 135       new Generic_Set_Operations
 136         (Tree_Operations  => Tree_Operations,
 137          Insert_With_Hint => Insert_With_Hint,
 138          Copy_Tree        => Copy_Tree,
 139          Delete_Tree      => Delete_Tree,
 140          Is_Less          => Is_Less_Node_Node,
 141          Free             => Free);
 142
 143    ---------
 144    -- "<" --
 145    ---------
 146
 147    function "<" (Left, Right : Cursor) return Boolean is
 148    begin
 149       if Left.Node = null then
 150          raise Constraint_Error with "Left cursor equals No_Element";
 151       end if;
 152
 153       if Right.Node = null then
 154          raise Constraint_Error with "Right cursor equals No_Element";
 155       end if;
 156
 157       if Left.Node.Element = null then
 158          raise Program_Error with "Left cursor is bad";
 159       end if;
 160
 161       if Right.Node.Element = null then
 162          raise Program_Error with "Right cursor is bad";
 163       end if;
 164
 165       pragma Assert (Vet (Left.Container.Tree, Left.Node),
 166                      "bad Left cursor in ""<""");
 167
 168       pragma Assert (Vet (Right.Container.Tree, Right.Node),
 169                      "bad Right cursor in ""<""");
 170
 171       return Left.Node.Element.all < Right.Node.Element.all;
 172    end "<";
 173
 174    function "<" (Left : Cursor; Right : Element_Type) return Boolean is
 175    begin
 176       if Left.Node = null then
 177          raise Constraint_Error with "Left cursor equals No_Element";
 178       end if;
 179
 180       if Left.Node.Element = null then
 181          raise Program_Error with "Left cursor is bad";
 182       end if;
 183
 184       pragma Assert (Vet (Left.Container.Tree, Left.Node),
 185                      "bad Left cursor in ""<""");
 186
 187       return Left.Node.Element.all < Right;
 188    end "<";
 189
 190    function "<" (Left : Element_Type; Right : Cursor) return Boolean is
 191    begin
 192       if Right.Node = null then
 193          raise Constraint_Error with "Right cursor equals No_Element";
 194       end if;
 195
 196       if Right.Node.Element = null then
 197          raise Program_Error with "Right cursor is bad";
 198       end if;
 199
 200       pragma Assert (Vet (Right.Container.Tree, Right.Node),
 201                      "bad Right cursor in ""<""");
 202
 203       return Left < Right.Node.Element.all;
 204    end "<";
 205
 206    ---------
 207    -- "=" --
 208    ---------
 209
 210    function "=" (Left, Right : Set) return Boolean is
 211
 212       function Is_Equal_Node_Node (L, R : Node_Access) return Boolean;
 213       pragma Inline (Is_Equal_Node_Node);
 214
 215       function Is_Equal is
 216         new Tree_Operations.Generic_Equal (Is_Equal_Node_Node);
 217
 218       ------------------------
 219       -- Is_Equal_Node_Node --
 220       ------------------------
 221
 222       function Is_Equal_Node_Node (L, R : Node_Access) return Boolean is
 223       begin
 224          return L.Element.all = R.Element.all;
 225       end Is_Equal_Node_Node;
 226
 227    --  Start of processing for "="
 228
 229    begin
 230       return Is_Equal (Left.Tree, Right.Tree);
 231    end "=";
 232
 233    ---------
 234    -- ">" --
 235    ---------
 236
 237    function ">" (Left, Right : Cursor) return Boolean is
 238    begin
 239       if Left.Node = null then
 240          raise Constraint_Error with "Left cursor equals No_Element";
 241       end if;
 242
 243       if Right.Node = null then
 244          raise Constraint_Error with "Right cursor equals No_Element";
 245       end if;
 246
 247       if Left.Node.Element = null then
 248          raise Program_Error with "Left cursor is bad";
 249       end if;
 250
 251       if Right.Node.Element = null then
 252          raise Program_Error with "Right cursor is bad";
 253       end if;
 254
 255       pragma Assert (Vet (Left.Container.Tree, Left.Node),
 256                      "bad Left cursor in "">""");
 257
 258       pragma Assert (Vet (Right.Container.Tree, Right.Node),
 259                      "bad Right cursor in "">""");
 260
 261       --  L > R same as R < L
 262
 263       return Right.Node.Element.all < Left.Node.Element.all;
 264    end ">";
 265
 266    function ">" (Left : Cursor; Right : Element_Type) return Boolean is
 267    begin
 268       if Left.Node = null then
 269          raise Constraint_Error with "Left cursor equals No_Element";
 270       end if;
 271
 272       if Left.Node.Element = null then
 273          raise Program_Error with "Left cursor is bad";
 274       end if;
 275
 276       pragma Assert (Vet (Left.Container.Tree, Left.Node),
 277                      "bad Left cursor in "">""");
 278
 279       return Right < Left.Node.Element.all;
 280    end ">";
 281
 282    function ">" (Left : Element_Type; Right : Cursor) return Boolean is
 283    begin
 284       if Right.Node = null then
 285          raise Constraint_Error with "Right cursor equals No_Element";
 286       end if;
 287
 288       if Right.Node.Element = null then
 289          raise Program_Error with "Right cursor is bad";
 290       end if;
 291
 292       pragma Assert (Vet (Right.Container.Tree, Right.Node),
 293                      "bad Right cursor in "">""");
 294
 295       return Right.Node.Element.all < Left;
 296    end ">";
 297
 298    ------------
 299    -- Adjust --
 300    ------------
 301
 302    procedure Adjust is
 303       new Tree_Operations.Generic_Adjust (Copy_Tree);
 304
 305    procedure Adjust (Container : in out Set) is
 306    begin
 307       Adjust (Container.Tree);
 308    end Adjust;
 309
 310    -------------
 311    -- Ceiling --
 312    -------------
 313
 314    function Ceiling (Container : Set; Item : Element_Type) return Cursor is
 315       Node : constant Node_Access :=
 316                Element_Keys.Ceiling (Container.Tree, Item);
 317
 318    begin
 319       if Node = null then
 320          return No_Element;
 321       end if;
 322
 323       return Cursor'(Container'Unrestricted_Access, Node);
 324    end Ceiling;
 325
 326    -----------
 327    -- Clear --
 328    -----------
 329
 330    procedure Clear is
 331       new Tree_Operations.Generic_Clear (Delete_Tree);
 332
 333    procedure Clear (Container : in out Set) is
 334    begin
 335       Clear (Container.Tree);
 336    end Clear;
 337
 338    -----------
 339    -- Color --
 340    -----------
 341
 342    function Color (Node : Node_Access) return Color_Type is
 343    begin
 344       return Node.Color;
 345    end Color;
 346
 347    --------------
 348    -- Contains --
 349    --------------
 350
 351    function Contains (Container : Set; Item : Element_Type) return Boolean is
 352    begin
 353       return Find (Container, Item) /= No_Element;
 354    end Contains;
 355
 356    ---------------
 357    -- Copy_Node --
 358    ---------------
 359
 360    function Copy_Node (Source : Node_Access) return Node_Access is
 361       Element : Element_Access := new Element_Type'(Source.Element.all);
 362
 363    begin
 364       return new Node_Type'(Parent  => null,
 365                             Left    => null,
 366                             Right   => null,
 367                             Color   => Source.Color,
 368                             Element => Element);
 369    exception
 370       when others =>
 371          Free_Element (Element);
 372          raise;
 373    end Copy_Node;
 374
 375    ------------
 376    -- Delete --
 377    ------------
 378
 379    procedure Delete (Container : in out Set; Position : in out Cursor) is
 380    begin
 381       if Position.Node = null then
 382          raise Constraint_Error with "Position cursor equals No_Element";
 383       end if;
 384
 385       if Position.Node.Element = null then
 386          raise Program_Error with "Position cursor is bad";
 387       end if;
 388
 389       if Position.Container /= Container'Unrestricted_Access then
 390          raise Program_Error with "Position cursor designates wrong set";
 391       end if;
 392
 393       pragma Assert (Vet (Container.Tree, Position.Node),
 394                      "bad cursor in Delete");
 395
 396       Tree_Operations.Delete_Node_Sans_Free (Container.Tree, Position.Node);
 397       Free (Position.Node);
 398       Position.Container := null;
 399    end Delete;
 400
 401    procedure Delete (Container : in out Set; Item : Element_Type) is
 402       X : Node_Access :=
 403             Element_Keys.Find (Container.Tree, Item);
 404
 405    begin
 406       if X = null then
 407          raise Constraint_Error with "attempt to delete element not in set";
 408       end if;
 409
 410       Tree_Operations.Delete_Node_Sans_Free (Container.Tree, X);
 411       Free (X);
 412    end Delete;
 413
 414    ------------------
 415    -- Delete_First --
 416    ------------------
 417
 418    procedure Delete_First (Container : in out Set) is
 419       Tree : Tree_Type renames Container.Tree;
 420       X    : Node_Access := Tree.First;
 421
 422    begin
 423       if X /= null then
 424          Tree_Operations.Delete_Node_Sans_Free (Tree, X);
 425          Free (X);
 426       end if;
 427    end Delete_First;
 428
 429    -----------------
 430    -- Delete_Last --
 431    -----------------
 432
 433    procedure Delete_Last (Container : in out Set) is
 434       Tree : Tree_Type renames Container.Tree;
 435       X    : Node_Access := Tree.Last;
 436
 437    begin
 438       if X /= null then
 439          Tree_Operations.Delete_Node_Sans_Free (Tree, X);
 440          Free (X);
 441       end if;
 442    end Delete_Last;
 443
 444    ----------------
 445    -- Difference --
 446    ----------------
 447
 448    procedure Difference (Target : in out Set; Source : Set) is
 449    begin
 450       Set_Ops.Difference (Target.Tree, Source.Tree);
 451    end Difference;
 452
 453    function Difference (Left, Right : Set) return Set is
 454       Tree : constant Tree_Type :=
 455                Set_Ops.Difference (Left.Tree, Right.Tree);
 456    begin
 457       return Set'(Controlled with Tree);
 458    end Difference;
 459
 460    -------------
 461    -- Element --
 462    -------------
 463
 464    function Element (Position : Cursor) return Element_Type is
 465    begin
 466       if Position.Node = null then
 467          raise Constraint_Error with "Position cursor equals No_Element";
 468       end if;
 469
 470       if Position.Node.Element = null then
 471          raise Program_Error with "Position cursor is bad";
 472       end if;
 473
 474       pragma Assert (Vet (Position.Container.Tree, Position.Node),
 475                      "bad cursor in Element");
 476
 477       return Position.Node.Element.all;
 478    end Element;
 479
 480    -------------------------
 481    -- Equivalent_Elements --
 482    -------------------------
 483
 484    function Equivalent_Elements (Left, Right : Element_Type) return Boolean is
 485    begin
 486       if Left < Right
 487         or else Right < Left
 488       then
 489          return False;
 490       else
 491          return True;
 492       end if;
 493    end Equivalent_Elements;
 494
 495    ---------------------
 496    -- Equivalent_Sets --
 497    ---------------------
 498
 499    function Equivalent_Sets (Left, Right : Set) return Boolean is
 500
 501       function Is_Equivalent_Node_Node (L, R : Node_Access) return Boolean;
 502       pragma Inline (Is_Equivalent_Node_Node);
 503
 504       function Is_Equivalent is
 505          new Tree_Operations.Generic_Equal (Is_Equivalent_Node_Node);
 506
 507       -----------------------------
 508       -- Is_Equivalent_Node_Node --
 509       -----------------------------
 510
 511       function Is_Equivalent_Node_Node (L, R : Node_Access) return Boolean is
 512       begin
 513          if L.Element.all < R.Element.all then
 514             return False;
 515          elsif R.Element.all < L.Element.all then
 516             return False;
 517          else
 518             return True;
 519          end if;
 520       end Is_Equivalent_Node_Node;
 521
 522    --  Start of processing for Equivalent_Sets
 523
 524    begin
 525       return Is_Equivalent (Left.Tree, Right.Tree);
 526    end Equivalent_Sets;
 527
 528    -------------
 529    -- Exclude --
 530    -------------
 531
 532    procedure Exclude (Container : in out Set; Item : Element_Type) is
 533       X : Node_Access :=
 534             Element_Keys.Find (Container.Tree, Item);
 535
 536    begin
 537       if X /= null then
 538          Tree_Operations.Delete_Node_Sans_Free (Container.Tree, X);
 539          Free (X);
 540       end if;
 541    end Exclude;
 542
 543    ----------
 544    -- Find --
 545    ----------
 546
 547    function Find (Container : Set; Item : Element_Type) return Cursor is
 548       Node : constant Node_Access :=
 549                Element_Keys.Find (Container.Tree, Item);
 550
 551    begin
 552       if Node = null then
 553          return No_Element;
 554       end if;
 555
 556       return Cursor'(Container'Unrestricted_Access, Node);
 557    end Find;
 558
 559    -----------
 560    -- First --
 561    -----------
 562
 563    function First (Container : Set) return Cursor is
 564    begin
 565       if Container.Tree.First = null then
 566          return No_Element;
 567       end if;
 568
 569       return Cursor'(Container'Unrestricted_Access, Container.Tree.First);
 570    end First;
 571
 572    -------------------
 573    -- First_Element --
 574    -------------------
 575
 576    function First_Element (Container : Set) return Element_Type is
 577    begin
 578       if Container.Tree.First = null then
 579          raise Constraint_Error with "set is empty";
 580       end if;
 581
 582       return Container.Tree.First.Element.all;
 583    end First_Element;
 584
 585    -----------
 586    -- Floor --
 587    -----------
 588
 589    function Floor (Container : Set; Item : Element_Type) return Cursor is
 590       Node : constant Node_Access :=
 591                Element_Keys.Floor (Container.Tree, Item);
 592
 593    begin
 594       if Node = null then
 595          return No_Element;
 596       end if;
 597
 598       return Cursor'(Container'Unrestricted_Access, Node);
 599    end Floor;
 600
 601    ----------
 602    -- Free --
 603    ----------
 604
 605    procedure Free (X : in out Node_Access) is
 606       procedure Deallocate is
 607         new Ada.Unchecked_Deallocation (Node_Type, Node_Access);
 608
 609    begin
 610       if X = null then
 611          return;
 612       end if;
 613
 614       X.Parent := X;
 615       X.Left := X;
 616       X.Right := X;
 617
 618       begin
 619          Free_Element (X.Element);
 620       exception
 621          when others =>
 622             X.Element := null;
 623             Deallocate (X);
 624             raise;
 625       end;
 626
 627       Deallocate (X);
 628    end Free;
 629
 630    ------------------
 631    -- Generic_Keys --
 632    ------------------
 633
 634    package body Generic_Keys is
 635
 636       -----------------------
 637       -- Local Subprograms --
 638       -----------------------
 639
 640       function Is_Greater_Key_Node
 641         (Left  : Key_Type;
 642          Right : Node_Access) return Boolean;
 643       pragma Inline (Is_Greater_Key_Node);
 644
 645       function Is_Less_Key_Node
 646         (Left  : Key_Type;
 647          Right : Node_Access) return Boolean;
 648       pragma Inline (Is_Less_Key_Node);
 649
 650       --------------------------
 651       -- Local Instantiations --
 652       --------------------------
 653
 654       package Key_Keys is
 655         new Red_Black_Trees.Generic_Keys
 656           (Tree_Operations     => Tree_Operations,
 657            Key_Type            => Key_Type,
 658            Is_Less_Key_Node    => Is_Less_Key_Node,
 659            Is_Greater_Key_Node => Is_Greater_Key_Node);
 660
 661       -------------
 662       -- Ceiling --
 663       -------------
 664
 665       function Ceiling (Container : Set; Key : Key_Type) return Cursor is
 666          Node : constant Node_Access :=
 667                   Key_Keys.Ceiling (Container.Tree, Key);
 668
 669       begin
 670          if Node = null then
 671             return No_Element;
 672          end if;
 673
 674          return Cursor'(Container'Unrestricted_Access, Node);
 675       end Ceiling;
 676
 677       --------------
 678       -- Contains --
 679       --------------
 680
 681       function Contains (Container : Set; Key : Key_Type) return Boolean is
 682       begin
 683          return Find (Container, Key) /= No_Element;
 684       end Contains;
 685
 686       ------------
 687       -- Delete --
 688       ------------
 689
 690       procedure Delete (Container : in out Set; Key : Key_Type) is
 691          X : Node_Access := Key_Keys.Find (Container.Tree, Key);
 692
 693       begin
 694          if X = null then
 695             raise Constraint_Error with "attempt to delete key not in set";
 696          end if;
 697
 698          Tree_Operations.Delete_Node_Sans_Free (Container.Tree, X);
 699          Free (X);
 700       end Delete;
 701
 702       -------------
 703       -- Element --
 704       -------------
 705
 706       function Element (Container : Set; Key : Key_Type) return Element_Type is
 707          Node : constant Node_Access :=
 708                   Key_Keys.Find (Container.Tree, Key);
 709
 710       begin
 711          if Node = null then
 712             raise Constraint_Error with "key not in set";
 713          end if;
 714
 715          return Node.Element.all;
 716       end Element;
 717
 718       ---------------------
 719       -- Equivalent_Keys --
 720       ---------------------
 721
 722       function Equivalent_Keys (Left, Right : Key_Type) return Boolean is
 723       begin
 724          if Left < Right
 725            or else Right < Left
 726          then
 727             return False;
 728          else
 729             return True;
 730          end if;
 731       end Equivalent_Keys;
 732
 733       -------------
 734       -- Exclude --
 735       -------------
 736
 737       procedure Exclude (Container : in out Set; Key : Key_Type) is
 738          X : Node_Access := Key_Keys.Find (Container.Tree, Key);
 739
 740       begin
 741          if X /= null then
 742             Tree_Operations.Delete_Node_Sans_Free (Container.Tree, X);
 743             Free (X);
 744          end if;
 745       end Exclude;
 746
 747       ----------
 748       -- Find --
 749       ----------
 750
 751       function Find (Container : Set; Key : Key_Type) return Cursor is
 752          Node : constant Node_Access :=
 753                   Key_Keys.Find (Container.Tree, Key);
 754
 755       begin
 756          if Node = null then
 757             return No_Element;
 758          end if;
 759
 760          return Cursor'(Container'Unrestricted_Access, Node);
 761       end Find;
 762
 763       -----------
 764       -- Floor --
 765       -----------
 766
 767       function Floor (Container : Set; Key : Key_Type) return Cursor is
 768          Node : constant Node_Access :=
 769                   Key_Keys.Floor (Container.Tree, Key);
 770
 771       begin
 772          if Node = null then
 773             return No_Element;
 774          end if;
 775
 776          return Cursor'(Container'Unrestricted_Access, Node);
 777       end Floor;
 778
 779       -------------------------
 780       -- Is_Greater_Key_Node --
 781       -------------------------
 782
 783       function Is_Greater_Key_Node
 784         (Left  : Key_Type;
 785          Right : Node_Access) return Boolean is
 786       begin
 787          return Key (Right.Element.all) < Left;
 788       end Is_Greater_Key_Node;
 789
 790       ----------------------
 791       -- Is_Less_Key_Node --
 792       ----------------------
 793
 794       function Is_Less_Key_Node
 795         (Left  : Key_Type;
 796          Right : Node_Access) return Boolean is
 797       begin
 798          return Left < Key (Right.Element.all);
 799       end Is_Less_Key_Node;
 800
 801       ---------
 802       -- Key --
 803       ---------
 804
 805       function Key (Position : Cursor) return Key_Type is
 806       begin
 807          if Position.Node = null then
 808             raise Constraint_Error with
 809               "Position cursor equals No_Element";
 810          end if;
 811
 812          if Position.Node.Element = null then
 813             raise Program_Error with
 814               "Position cursor is bad";
 815          end if;
 816
 817          pragma Assert (Vet (Position.Container.Tree, Position.Node),
 818                         "bad cursor in Key");
 819
 820          return Key (Position.Node.Element.all);
 821       end Key;
 822
 823       -------------
 824       -- Replace --
 825       -------------
 826
 827       procedure Replace
 828         (Container : in out Set;
 829          Key       : Key_Type;
 830          New_Item  : Element_Type)
 831       is
 832          Node : constant Node_Access := Key_Keys.Find (Container.Tree, Key);
 833
 834       begin
 835          if Node = null then
 836             raise Constraint_Error with
 837               "attempt to replace key not in set";
 838          end if;
 839
 840          Replace_Element (Container.Tree, Node, New_Item);
 841       end Replace;
 842
 843       -----------------------------------
 844       -- Update_Element_Preserving_Key --
 845       -----------------------------------
 846
 847       procedure Update_Element_Preserving_Key
 848         (Container : in out Set;
 849          Position  : Cursor;
 850          Process   : not null access
 851                         procedure (Element : in out Element_Type))
 852       is
 853          Tree : Tree_Type renames Container.Tree;
 854
 855       begin
 856          if Position.Node = null then
 857             raise Constraint_Error with "Position cursor equals No_Element";
 858          end if;
 859
 860          if Position.Node.Element = null then
 861             raise Program_Error with "Position cursor is bad";
 862          end if;
 863
 864          if Position.Container /= Container'Unrestricted_Access then
 865             raise Program_Error with "Position cursor designates wrong set";
 866          end if;
 867
 868          pragma Assert (Vet (Container.Tree, Position.Node),
 869                         "bad cursor in Update_Element_Preserving_Key");
 870
 871          declare
 872             E : Element_Type renames Position.Node.Element.all;
 873             K : constant Key_Type := Key (E);
 874
 875             B : Natural renames Tree.Busy;
 876             L : Natural renames Tree.Lock;
 877
 878          begin
 879             B := B + 1;
 880             L := L + 1;
 881
 882             begin
 883                Process (E);
 884             exception
 885                when others =>
 886                   L := L - 1;
 887                   B := B - 1;
 888                   raise;
 889             end;
 890
 891             L := L - 1;
 892             B := B - 1;
 893
 894             if Equivalent_Keys (K, Key (E)) then
 895                return;
 896             end if;
 897          end;
 898
 899          declare
 900             X : Node_Access := Position.Node;
 901          begin
 902             Tree_Operations.Delete_Node_Sans_Free (Tree, X);
 903             Free (X);
 904          end;
 905
 906          raise Program_Error with "key was modified";
 907       end Update_Element_Preserving_Key;
 908
 909    end Generic_Keys;
 910
 911    -----------------
 912    -- Has_Element --
 913    -----------------
 914
 915    function Has_Element (Position : Cursor) return Boolean is
 916    begin
 917       return Position /= No_Element;
 918    end Has_Element;
 919
 920    -------------
 921    -- Include --
 922    -------------
 923
 924    procedure Include (Container : in out Set; New_Item  : Element_Type) is
 925       Position : Cursor;
 926       Inserted : Boolean;
 927
 928       X : Element_Access;
 929
 930    begin
 931       Insert (Container, New_Item, Position, Inserted);
 932
 933       if not Inserted then
 934          if Container.Tree.Lock > 0 then
 935             raise Program_Error with
 936               "attempt to tamper with cursors (set is locked)";
 937          end if;
 938
 939          X := Position.Node.Element;
 940          Position.Node.Element := new Element_Type'(New_Item);
 941          Free_Element (X);
 942       end if;
 943    end Include;
 944
 945    ------------
 946    -- Insert --
 947    ------------
 948
 949    procedure Insert
 950      (Container : in out Set;
 951       New_Item  : Element_Type;
 952       Position  : out Cursor;
 953       Inserted  : out Boolean)
 954    is
 955    begin
 956       Insert_Sans_Hint
 957         (Container.Tree,
 958          New_Item,
 959          Position.Node,
 960          Inserted);
 961
 962       Position.Container := Container'Unrestricted_Access;
 963    end Insert;
 964
 965    procedure Insert (Container : in out Set; New_Item  : Element_Type) is
 966       Position : Cursor;
 967       Inserted : Boolean;
 968    begin
 969       Insert (Container, New_Item, Position, Inserted);
 970
 971       if not Inserted then
 972          raise Constraint_Error with
 973            "attempt to insert element already in set";
 974       end if;
 975    end Insert;
 976
 977    ----------------------
 978    -- Insert_Sans_Hint --
 979    ----------------------
 980
 981    procedure Insert_Sans_Hint
 982      (Tree     : in out Tree_Type;
 983       New_Item : Element_Type;
 984       Node     : out Node_Access;
 985       Inserted : out Boolean)
 986    is
 987       function New_Node return Node_Access;
 988       pragma Inline (New_Node);
 989
 990       procedure Insert_Post is
 991         new Element_Keys.Generic_Insert_Post (New_Node);
 992
 993       procedure Conditional_Insert_Sans_Hint is
 994         new Element_Keys.Generic_Conditional_Insert (Insert_Post);
 995
 996       --------------
 997       -- New_Node --
 998       --------------
 999
1000       function New_Node return Node_Access is
1001          Element : Element_Access := new Element_Type'(New_Item);
1002
1003       begin
1004          return new Node_Type'(Parent  => null,
1005                                Left    => null,
1006                                Right   => null,
1007                                Color   => Red_Black_Trees.Red,
1008                                Element => Element);
1009       exception
1010          when others =>
1011             Free_Element (Element);
1012             raise;
1013       end New_Node;
1014
1015    --  Start of processing for Insert_Sans_Hint
1016
1017    begin
1018       Conditional_Insert_Sans_Hint
1019         (Tree,
1020          New_Item,
1021          Node,
1022          Inserted);
1023    end Insert_Sans_Hint;
1024
1025    ----------------------
1026    -- Insert_With_Hint --
1027    ----------------------
1028
1029    procedure Insert_With_Hint
1030      (Dst_Tree : in out Tree_Type;
1031       Dst_Hint : Node_Access;
1032       Src_Node : Node_Access;
1033       Dst_Node : out Node_Access)
1034    is
1035       Success  : Boolean;
1036
1037       function New_Node return Node_Access;
1038
1039       procedure Insert_Post is
1040         new Element_Keys.Generic_Insert_Post (New_Node);
1041
1042       procedure Insert_Sans_Hint is
1043         new Element_Keys.Generic_Conditional_Insert (Insert_Post);
1044
1045       procedure Insert_With_Hint is
1046          new Element_Keys.Generic_Conditional_Insert_With_Hint
1047             (Insert_Post,
1048              Insert_Sans_Hint);
1049
1050       --------------
1051       -- New_Node --
1052       --------------
1053
1054       function New_Node return Node_Access is
1055          Element : Element_Access :=
1056                      new Element_Type'(Src_Node.Element.all);
1057          Node    : Node_Access;
1058
1059       begin
1060          begin
1061             Node := new Node_Type;
1062          exception
1063             when others =>
1064                Free_Element (Element);
1065                raise;
1066          end;
1067
1068          Node.Element := Element;
1069          return Node;
1070       end New_Node;
1071
1072    --  Start of processing for Insert_With_Hint
1073
1074    begin
1075       Insert_With_Hint
1076         (Dst_Tree,
1077          Dst_Hint,
1078          Src_Node.Element.all,
1079          Dst_Node,
1080          Success);
1081    end Insert_With_Hint;
1082
1083    ------------------
1084    -- Intersection --
1085    ------------------
1086
1087    procedure Intersection (Target : in out Set; Source : Set) is
1088    begin
1089       Set_Ops.Intersection (Target.Tree, Source.Tree);
1090    end Intersection;
1091
1092    function Intersection (Left, Right : Set) return Set is
1093       Tree : constant Tree_Type :=
1094                Set_Ops.Intersection (Left.Tree, Right.Tree);
1095    begin
1096       return Set'(Controlled with Tree);
1097    end Intersection;
1098
1099    --------------
1100    -- Is_Empty --
1101    --------------
1102
1103    function Is_Empty (Container : Set) return Boolean is
1104    begin
1105       return Container.Tree.Length = 0;
1106    end Is_Empty;
1107
1108    -----------------------------
1109    -- Is_Greater_Element_Node --
1110    -----------------------------
1111
1112    function Is_Greater_Element_Node
1113      (Left  : Element_Type;
1114       Right : Node_Access) return Boolean is
1115    begin
1116       --  e > node same as node < e
1117
1118       return Right.Element.all < Left;
1119    end Is_Greater_Element_Node;
1120
1121    --------------------------
1122    -- Is_Less_Element_Node --
1123    --------------------------
1124
1125    function Is_Less_Element_Node
1126      (Left  : Element_Type;
1127       Right : Node_Access) return Boolean is
1128    begin
1129       return Left < Right.Element.all;
1130    end Is_Less_Element_Node;
1131
1132    -----------------------
1133    -- Is_Less_Node_Node --
1134    -----------------------
1135
1136    function Is_Less_Node_Node (L, R : Node_Access) return Boolean is
1137    begin
1138       return L.Element.all < R.Element.all;
1139    end Is_Less_Node_Node;
1140
1141    ---------------
1142    -- Is_Subset --
1143    ---------------
1144
1145    function Is_Subset (Subset : Set; Of_Set : Set) return Boolean is
1146    begin
1147       return Set_Ops.Is_Subset (Subset => Subset.Tree, Of_Set => Of_Set.Tree);
1148    end Is_Subset;
1149
1150    -------------
1151    -- Iterate --
1152    -------------
1153
1154    procedure Iterate
1155      (Container : Set;
1156       Process   : not null access procedure (Position : Cursor))
1157    is
1158       procedure Process_Node (Node : Node_Access);
1159       pragma Inline (Process_Node);
1160
1161       procedure Local_Iterate is
1162         new Tree_Operations.Generic_Iteration (Process_Node);
1163
1164       ------------------
1165       -- Process_Node --
1166       ------------------
1167
1168       procedure Process_Node (Node : Node_Access) is
1169       begin
1170          Process (Cursor'(Container'Unrestricted_Access, Node));
1171       end Process_Node;
1172
1173       T : Tree_Type renames Container.Tree'Unrestricted_Access.all;
1174       B : Natural renames T.Busy;
1175
1176    --  Start of prccessing for Iterate
1177
1178    begin
1179       B := B + 1;
1180
1181       begin
1182          Local_Iterate (T);
1183       exception
1184          when others =>
1185             B := B - 1;
1186             raise;
1187       end;
1188
1189       B := B - 1;
1190    end Iterate;
1191
1192    ----------
1193    -- Last --
1194    ----------
1195
1196    function Last (Container : Set) return Cursor is
1197    begin
1198       if Container.Tree.Last = null then
1199          return No_Element;
1200       end if;
1201
1202       return Cursor'(Container'Unrestricted_Access, Container.Tree.Last);
1203    end Last;
1204
1205    ------------------
1206    -- Last_Element --
1207    ------------------
1208
1209    function Last_Element (Container : Set) return Element_Type is
1210    begin
1211       if Container.Tree.Last = null then
1212          raise Constraint_Error with "set is empty";
1213       end if;
1214
1215       return Container.Tree.Last.Element.all;
1216    end Last_Element;
1217
1218    ----------
1219    -- Left --
1220    ----------
1221
1222    function Left (Node : Node_Access) return Node_Access is
1223    begin
1224       return Node.Left;
1225    end Left;
1226
1227    ------------
1228    -- Length --
1229    ------------
1230
1231    function Length (Container : Set) return Count_Type is
1232    begin
1233       return Container.Tree.Length;
1234    end Length;
1235
1236    ----------
1237    -- Move --
1238    ----------
1239
1240    procedure Move is
1241       new Tree_Operations.Generic_Move (Clear);
1242
1243    procedure Move (Target : in out Set; Source : in out Set) is
1244    begin
1245       Move (Target => Target.Tree, Source => Source.Tree);
1246    end Move;
1247
1248    ----------
1249    -- Next --
1250    ----------
1251
1252    procedure Next (Position : in out Cursor) is
1253    begin
1254       Position := Next (Position);
1255    end Next;
1256
1257    function Next (Position : Cursor) return Cursor is
1258    begin
1259       if Position = No_Element then
1260          return No_Element;
1261       end if;
1262
1263       if Position.Node.Element = null then
1264          raise Program_Error with "Position cursor is bad";
1265       end if;
1266
1267       pragma Assert (Vet (Position.Container.Tree, Position.Node),
1268                      "bad cursor in Next");
1269
1270       declare
1271          Node : constant Node_Access :=
1272                   Tree_Operations.Next (Position.Node);
1273
1274       begin
1275          if Node = null then
1276             return No_Element;
1277          end if;
1278
1279          return Cursor'(Position.Container, Node);
1280       end;
1281    end Next;
1282
1283    -------------
1284    -- Overlap --
1285    -------------
1286
1287    function Overlap (Left, Right : Set) return Boolean is
1288    begin
1289       return Set_Ops.Overlap (Left.Tree, Right.Tree);
1290    end Overlap;
1291
1292    ------------
1293    -- Parent --
1294    ------------
1295
1296    function Parent (Node : Node_Access) return Node_Access is
1297    begin
1298       return Node.Parent;
1299    end Parent;
1300
1301    --------------
1302    -- Previous --
1303    --------------
1304
1305    procedure Previous (Position : in out Cursor) is
1306    begin
1307       Position := Previous (Position);
1308    end Previous;
1309
1310    function Previous (Position : Cursor) return Cursor is
1311    begin
1312       if Position = No_Element then
1313          return No_Element;
1314       end if;
1315
1316       if Position.Node.Element = null then
1317          raise Program_Error with "Position cursor is bad";
1318       end if;
1319
1320       pragma Assert (Vet (Position.Container.Tree, Position.Node),
1321                      "bad cursor in Previous");
1322
1323       declare
1324          Node : constant Node_Access :=
1325                   Tree_Operations.Previous (Position.Node);
1326
1327       begin
1328          if Node = null then
1329             return No_Element;
1330          end if;
1331
1332          return Cursor'(Position.Container, Node);
1333       end;
1334    end Previous;
1335
1336    -------------------
1337    -- Query_Element --
1338    -------------------
1339
1340    procedure Query_Element
1341      (Position  : Cursor;
1342       Process   : not null access procedure (Element : Element_Type))
1343    is
1344    begin
1345       if Position.Node = null then
1346          raise Constraint_Error with "Position cursor equals No_Element";
1347       end if;
1348
1349       if Position.Node.Element = null then
1350          raise Program_Error with "Position cursor is bad";
1351       end if;
1352
1353       pragma Assert (Vet (Position.Container.Tree, Position.Node),
1354                      "bad cursor in Query_Element");
1355
1356       declare
1357          T : Tree_Type renames Position.Container.Tree;
1358
1359          B : Natural renames T.Busy;
1360          L : Natural renames T.Lock;
1361
1362       begin
1363          B := B + 1;
1364          L := L + 1;
1365
1366          begin
1367             Process (Position.Node.Element.all);
1368          exception
1369             when others =>
1370                L := L - 1;
1371                B := B - 1;
1372                raise;
1373          end;
1374
1375          L := L - 1;
1376          B := B - 1;
1377       end;
1378    end Query_Element;
1379
1380    ----------
1381    -- Read --
1382    ----------
1383
1384    procedure Read
1385      (Stream    : access Root_Stream_Type'Class;
1386       Container : out Set)
1387    is
1388       function Read_Node
1389         (Stream : access Root_Stream_Type'Class) return Node_Access;
1390       pragma Inline (Read_Node);
1391
1392       procedure Read is
1393          new Tree_Operations.Generic_Read (Clear, Read_Node);
1394
1395       ---------------
1396       -- Read_Node --
1397       ---------------
1398
1399       function Read_Node
1400         (Stream : access Root_Stream_Type'Class) return Node_Access
1401       is
1402          Node : Node_Access := new Node_Type;
1403
1404       begin
1405          Node.Element := new Element_Type'(Element_Type'Input (Stream));
1406          return Node;
1407
1408       exception
1409          when others =>
1410             Free (Node);  --  Note that Free deallocates elem too
1411             raise;
1412       end Read_Node;
1413
1414    --  Start of processing for Read
1415
1416    begin
1417       Read (Stream, Container.Tree);
1418    end Read;
1419
1420    procedure Read
1421      (Stream : access Root_Stream_Type'Class;
1422       Item   : out Cursor)
1423    is
1424    begin
1425       raise Program_Error with "attempt to stream set cursor";
1426    end Read;
1427
1428    -------------
1429    -- Replace --
1430    -------------
1431
1432    procedure Replace (Container : in out Set; New_Item : Element_Type) is
1433       Node : constant Node_Access :=
1434                Element_Keys.Find (Container.Tree, New_Item);
1435
1436       X : Element_Access;
1437
1438    begin
1439       if Node = null then
1440          raise Constraint_Error with "attempt to replace element not in set";
1441       end if;
1442
1443       if Container.Tree.Lock > 0 then
1444          raise Program_Error with
1445            "attempt to tamper with cursors (set is locked)";
1446       end if;
1447
1448       X := Node.Element;
1449       Node.Element := new Element_Type'(New_Item);
1450       Free_Element (X);
1451    end Replace;
1452
1453    ---------------------
1454    -- Replace_Element --
1455    ---------------------
1456
1457    procedure Replace_Element
1458      (Tree : in out Tree_Type;
1459       Node : Node_Access;
1460       Item : Element_Type)
1461    is
1462       pragma Assert (Node /= null);
1463       pragma Assert (Node.Element /= null);
1464
1465       function New_Node return Node_Access;
1466       pragma Inline (New_Node);
1467
1468       procedure Local_Insert_Post is
1469          new Element_Keys.Generic_Insert_Post (New_Node);
1470
1471       procedure Local_Insert_Sans_Hint is
1472          new Element_Keys.Generic_Conditional_Insert (Local_Insert_Post);
1473
1474       procedure Local_Insert_With_Hint is
1475          new Element_Keys.Generic_Conditional_Insert_With_Hint
1476         (Local_Insert_Post,
1477          Local_Insert_Sans_Hint);
1478
1479       --------------
1480       -- New_Node --
1481       --------------
1482
1483       function New_Node return Node_Access is
1484       begin
1485          Node.Element := new Element_Type'(Item);  -- OK if fails
1486          Node.Color := Red;
1487          Node.Parent := null;
1488          Node.Right := null;
1489          Node.Left := null;
1490
1491          return Node;
1492       end New_Node;
1493
1494       Hint     : Node_Access;
1495       Result   : Node_Access;
1496       Inserted : Boolean;
1497
1498       X : Element_Access := Node.Element;
1499
1500       --  Start of processing for Insert
1501
1502    begin
1503       if Item < Node.Element.all
1504         or else Node.Element.all < Item
1505       then
1506          null;
1507
1508       else
1509          if Tree.Lock > 0 then
1510             raise Program_Error with
1511               "attempt to tamper with cursors (set is locked)";
1512          end if;
1513
1514          Node.Element := new Element_Type'(Item);
1515          Free_Element (X);
1516
1517          return;
1518       end if;
1519
1520       Hint := Element_Keys.Ceiling (Tree, Item);
1521
1522       if Hint = null then
1523          null;
1524
1525       elsif Item < Hint.Element.all then
1526          if Hint = Node then
1527             if Tree.Lock > 0 then
1528                raise Program_Error with
1529                  "attempt to tamper with cursors (set is locked)";
1530             end if;
1531
1532             Node.Element := new Element_Type'(Item);
1533             Free_Element (X);
1534
1535             return;
1536          end if;
1537
1538       else
1539          pragma Assert (not (Hint.Element.all < Item));
1540          raise Program_Error with "attempt to replace existing element";
1541       end if;
1542
1543       Tree_Operations.Delete_Node_Sans_Free (Tree, Node);  -- Checks busy-bit
1544
1545       Local_Insert_With_Hint
1546         (Tree     => Tree,
1547          Position => Hint,
1548          Key      => Item,
1549          Node     => Result,
1550          Inserted => Inserted);
1551
1552       pragma Assert (Inserted);
1553       pragma Assert (Result = Node);
1554
1555       Free_Element (X);
1556    end Replace_Element;
1557
1558    procedure Replace_Element
1559     (Container : in out Set;
1560      Position  : Cursor;
1561      New_Item  : Element_Type)
1562    is
1563    begin
1564       if Position.Node = null then
1565          raise Constraint_Error with "Position cursor equals No_Element";
1566       end if;
1567
1568       if Position.Node.Element = null then
1569          raise Program_Error with "Position cursor is bad";
1570       end if;
1571
1572       if Position.Container /= Container'Unrestricted_Access then
1573          raise Program_Error with "Position cursor designates wrong set";
1574       end if;
1575
1576       pragma Assert (Vet (Container.Tree, Position.Node),
1577                      "bad cursor in Replace_Element");
1578
1579       Replace_Element (Container.Tree, Position.Node, New_Item);
1580    end Replace_Element;
1581
1582    ---------------------
1583    -- Reverse_Iterate --
1584    ---------------------
1585
1586    procedure Reverse_Iterate
1587      (Container : Set;
1588       Process   : not null access procedure (Position : Cursor))
1589    is
1590       procedure Process_Node (Node : Node_Access);
1591       pragma Inline (Process_Node);
1592
1593       procedure Local_Reverse_Iterate is
1594          new Tree_Operations.Generic_Reverse_Iteration (Process_Node);
1595
1596       ------------------
1597       -- Process_Node --
1598       ------------------
1599
1600       procedure Process_Node (Node : Node_Access) is
1601       begin
1602          Process (Cursor'(Container'Unrestricted_Access, Node));
1603       end Process_Node;
1604
1605       T : Tree_Type renames Container.Tree'Unrestricted_Access.all;
1606       B : Natural renames T.Busy;
1607
1608    --  Start of processing for Reverse_Iterate
1609
1610    begin
1611       B := B + 1;
1612
1613       begin
1614          Local_Reverse_Iterate (T);
1615       exception
1616          when others =>
1617             B := B - 1;
1618             raise;
1619       end;
1620
1621       B := B - 1;
1622    end Reverse_Iterate;
1623
1624    -----------
1625    -- Right --
1626    -----------
1627
1628    function Right (Node : Node_Access) return Node_Access is
1629    begin
1630       return Node.Right;
1631    end Right;
1632
1633    ---------------
1634    -- Set_Color --
1635    ---------------
1636
1637    procedure Set_Color (Node : Node_Access; Color : Color_Type) is
1638    begin
1639       Node.Color := Color;
1640    end Set_Color;
1641
1642    --------------
1643    -- Set_Left --
1644    --------------
1645
1646    procedure Set_Left (Node : Node_Access; Left : Node_Access) is
1647    begin
1648       Node.Left := Left;
1649    end Set_Left;
1650
1651    ----------------
1652    -- Set_Parent --
1653    ----------------
1654
1655    procedure Set_Parent (Node : Node_Access; Parent : Node_Access) is
1656    begin
1657       Node.Parent := Parent;
1658    end Set_Parent;
1659
1660    ---------------
1661    -- Set_Right --
1662    ---------------
1663
1664    procedure Set_Right (Node : Node_Access; Right : Node_Access) is
1665    begin
1666       Node.Right := Right;
1667    end Set_Right;
1668
1669    --------------------------
1670    -- Symmetric_Difference --
1671    --------------------------
1672
1673    procedure Symmetric_Difference (Target : in out Set; Source : Set) is
1674    begin
1675       Set_Ops.Symmetric_Difference (Target.Tree, Source.Tree);
1676    end Symmetric_Difference;
1677
1678    function Symmetric_Difference (Left, Right : Set) return Set is
1679       Tree : constant Tree_Type :=
1680                Set_Ops.Symmetric_Difference (Left.Tree, Right.Tree);
1681    begin
1682       return Set'(Controlled with Tree);
1683    end Symmetric_Difference;
1684
1685    ------------
1686    -- To_Set --
1687    ------------
1688
1689    function To_Set (New_Item : Element_Type) return Set is
1690       Tree     : Tree_Type;
1691       Node     : Node_Access;
1692       Inserted : Boolean;
1693
1694    begin
1695       Insert_Sans_Hint (Tree, New_Item, Node, Inserted);
1696       return Set'(Controlled with Tree);
1697    end To_Set;
1698
1699    -----------
1700    -- Union --
1701    -----------
1702
1703    procedure Union (Target : in out Set; Source : Set) is
1704    begin
1705       Set_Ops.Union (Target.Tree, Source.Tree);
1706    end Union;
1707
1708    function Union (Left, Right : Set) return Set is
1709       Tree : constant Tree_Type :=
1710                Set_Ops.Union (Left.Tree, Right.Tree);
1711    begin
1712       return Set'(Controlled with Tree);
1713    end Union;
1714
1715    -----------
1716    -- Write --
1717    -----------
1718
1719    procedure Write
1720      (Stream    : access Root_Stream_Type'Class;
1721       Container : Set)
1722    is
1723       procedure Write_Node
1724         (Stream : access Root_Stream_Type'Class;
1725          Node   : Node_Access);
1726       pragma Inline (Write_Node);
1727
1728       procedure Write is
1729          new Tree_Operations.Generic_Write (Write_Node);
1730
1731       ----------------
1732       -- Write_Node --
1733       ----------------
1734
1735       procedure Write_Node
1736         (Stream : access Root_Stream_Type'Class;
1737          Node   : Node_Access)
1738       is
1739       begin
1740          Element_Type'Output (Stream, Node.Element.all);
1741       end Write_Node;
1742
1743    --  Start of processing for Write
1744
1745    begin
1746       Write (Stream, Container.Tree);
1747    end Write;
1748
1749    procedure Write
1750      (Stream : access Root_Stream_Type'Class;
1751       Item   : Cursor)
1752    is
1753    begin
1754       raise Program_Error with "attempt to stream set cursor";
1755    end Write;
1756
1757 end Ada.Containers.Indefinite_Ordered_Sets;