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1 706 jeremybenn
------------------------------------------------------------------------------
2
--                                                                          --
3
--                         GNAT LIBRARY COMPONENTS                          --
4
--                                                                          --
5
--    A D A . C O N T A I N E R S . B O U N D E D _ H A S H E D _ S E T S   --
6
--                                                                          --
7
--                                 B o d y                                  --
8
--                                                                          --
9
--          Copyright (C) 2004-2011, Free Software Foundation, Inc.         --
10
--                                                                          --
11
-- GNAT is free software;  you can  redistribute it  and/or modify it under --
12
-- terms of the  GNU General Public License as published  by the Free Soft- --
13
-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
14
-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
15
-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
16
-- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
17
--                                                                          --
18
-- As a special exception under Section 7 of GPL version 3, you are granted --
19
-- additional permissions described in the GCC Runtime Library Exception,   --
20
-- version 3.1, as published by the Free Software Foundation.               --
21
--                                                                          --
22
-- You should have received a copy of the GNU General Public License and    --
23
-- a copy of the GCC Runtime Library Exception along with this program;     --
24
-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
25
-- <http://www.gnu.org/licenses/>.                                          --
26
--                                                                          --
27
-- This unit was originally developed by Matthew J Heaney.                  --
28
------------------------------------------------------------------------------
29
 
30
with Ada.Containers.Hash_Tables.Generic_Bounded_Operations;
31
pragma Elaborate_All (Ada.Containers.Hash_Tables.Generic_Bounded_Operations);
32
 
33
with Ada.Containers.Hash_Tables.Generic_Bounded_Keys;
34
pragma Elaborate_All (Ada.Containers.Hash_Tables.Generic_Bounded_Keys);
35
 
36
with Ada.Containers.Prime_Numbers; use Ada.Containers.Prime_Numbers;
37
with Ada.Finalization;             use Ada.Finalization;
38
 
39
with System; use type System.Address;
40
 
41
package body Ada.Containers.Bounded_Hashed_Sets is
42
 
43
   type Iterator is new Limited_Controlled and
44
     Set_Iterator_Interfaces.Forward_Iterator with
45
   record
46
      Container : Set_Access;
47
   end record;
48
 
49
   overriding procedure Finalize (Object : in out Iterator);
50
 
51
   overriding function First (Object : Iterator) return Cursor;
52
 
53
   overriding function Next
54
     (Object   : Iterator;
55
      Position : Cursor) return Cursor;
56
 
57
   -----------------------
58
   -- Local Subprograms --
59
   -----------------------
60
 
61
   function Equivalent_Keys
62
     (Key  : Element_Type;
63
      Node : Node_Type) return Boolean;
64
   pragma Inline (Equivalent_Keys);
65
 
66
   function Hash_Node (Node : Node_Type) return Hash_Type;
67
   pragma Inline (Hash_Node);
68
 
69
   procedure Insert
70
     (Container : in out Set;
71
      New_Item  : Element_Type;
72
      Node      : out Count_Type;
73
      Inserted  : out Boolean);
74
 
75
   function Is_In (HT : Set; Key : Node_Type) return Boolean;
76
   pragma Inline (Is_In);
77
 
78
   procedure Set_Element (Node : in out Node_Type; Item : Element_Type);
79
   pragma Inline (Set_Element);
80
 
81
   function Next (Node : Node_Type) return Count_Type;
82
   pragma Inline (Next);
83
 
84
   procedure Set_Next (Node : in out Node_Type; Next : Count_Type);
85
   pragma Inline (Set_Next);
86
 
87
   function Vet (Position : Cursor) return Boolean;
88
 
89
   --------------------------
90
   -- Local Instantiations --
91
   --------------------------
92
 
93
   package HT_Ops is new Hash_Tables.Generic_Bounded_Operations
94
     (HT_Types  => HT_Types,
95
      Hash_Node => Hash_Node,
96
      Next      => Next,
97
      Set_Next  => Set_Next);
98
 
99
   package Element_Keys is new Hash_Tables.Generic_Bounded_Keys
100
     (HT_Types        => HT_Types,
101
      Next            => Next,
102
      Set_Next        => Set_Next,
103
      Key_Type        => Element_Type,
104
      Hash            => Hash,
105
      Equivalent_Keys => Equivalent_Keys);
106
 
107
   procedure Replace_Element is
108
      new Element_Keys.Generic_Replace_Element (Hash_Node, Set_Element);
109
 
110
   ---------
111
   -- "=" --
112
   ---------
113
 
114
   function "=" (Left, Right : Set) return Boolean is
115
      function Find_Equal_Key
116
        (R_HT   : Hash_Table_Type'Class;
117
         L_Node : Node_Type) return Boolean;
118
      pragma Inline (Find_Equal_Key);
119
 
120
      function Is_Equal is
121
        new HT_Ops.Generic_Equal (Find_Equal_Key);
122
 
123
      --------------------
124
      -- Find_Equal_Key --
125
      --------------------
126
 
127
      function Find_Equal_Key
128
        (R_HT   : Hash_Table_Type'Class;
129
         L_Node : Node_Type) return Boolean
130
      is
131
         R_Index : constant Hash_Type :=
132
                     Element_Keys.Index (R_HT, L_Node.Element);
133
 
134
         R_Node  : Count_Type := R_HT.Buckets (R_Index);
135
 
136
      begin
137
         loop
138
            if R_Node = 0 then
139
               return False;
140
            end if;
141
 
142
            if L_Node.Element = R_HT.Nodes (R_Node).Element then
143
               return True;
144
            end if;
145
 
146
            R_Node := Next (R_HT.Nodes (R_Node));
147
         end loop;
148
      end Find_Equal_Key;
149
 
150
   --  Start of processing for "="
151
 
152
   begin
153
      return Is_Equal (Left, Right);
154
   end "=";
155
 
156
   ------------
157
   -- Assign --
158
   ------------
159
 
160
   procedure Assign (Target : in out Set; Source : Set) is
161
      procedure Insert_Element (Source_Node : Count_Type);
162
 
163
      procedure Insert_Elements is
164
         new HT_Ops.Generic_Iteration (Insert_Element);
165
 
166
      --------------------
167
      -- Insert_Element --
168
      --------------------
169
 
170
      procedure Insert_Element (Source_Node : Count_Type) is
171
         N : Node_Type renames Source.Nodes (Source_Node);
172
         X : Count_Type;
173
         B : Boolean;
174
      begin
175
         Insert (Target, N.Element, X, B);
176
         pragma Assert (B);
177
      end Insert_Element;
178
 
179
   --  Start of processing for Assign
180
 
181
   begin
182
      if Target'Address = Source'Address then
183
         return;
184
      end if;
185
 
186
      if Target.Capacity < Source.Length then
187
         raise Capacity_Error
188
           with "Target capacity is less than Source length";
189
      end if;
190
 
191
      HT_Ops.Clear (Target);
192
      Insert_Elements (Source);
193
   end Assign;
194
 
195
   --------------
196
   -- Capacity --
197
   --------------
198
 
199
   function Capacity (Container : Set) return Count_Type is
200
   begin
201
      return Container.Capacity;
202
   end Capacity;
203
 
204
   -----------
205
   -- Clear --
206
   -----------
207
 
208
   procedure Clear (Container : in out Set) is
209
   begin
210
      HT_Ops.Clear (Container);
211
   end Clear;
212
 
213
   ------------------------
214
   -- Constant_Reference --
215
   ------------------------
216
 
217
   function Constant_Reference
218
     (Container : aliased Set;
219
      Position  : Cursor) return Constant_Reference_Type
220
   is
221
   begin
222
      if Position.Container = null then
223
         raise Constraint_Error with "Position cursor has no element";
224
      end if;
225
 
226
      if Position.Container /= Container'Unrestricted_Access then
227
         raise Program_Error with
228
           "Position cursor designates wrong container";
229
      end if;
230
 
231
      pragma Assert (Vet (Position), "bad cursor in Constant_Reference");
232
 
233
      declare
234
         N : Node_Type renames Container.Nodes (Position.Node);
235
      begin
236
         return (Element => N.Element'Access);
237
      end;
238
   end Constant_Reference;
239
 
240
   --------------
241
   -- Contains --
242
   --------------
243
 
244
   function Contains (Container : Set; Item : Element_Type) return Boolean is
245
   begin
246
      return Find (Container, Item) /= No_Element;
247
   end Contains;
248
 
249
   ----------
250
   -- Copy --
251
   ----------
252
 
253
   function Copy
254
     (Source   : Set;
255
      Capacity : Count_Type := 0;
256
      Modulus  : Hash_Type := 0) return Set
257
   is
258
      C : Count_Type;
259
      M : Hash_Type;
260
 
261
   begin
262
      if Capacity = 0 then
263
         C := Source.Length;
264
      elsif Capacity >= Source.Length then
265
         C := Capacity;
266
      else
267
         raise Capacity_Error with "Capacity value too small";
268
      end if;
269
 
270
      if Modulus = 0 then
271
         M := Default_Modulus (C);
272
      else
273
         M := Modulus;
274
      end if;
275
 
276
      return Target : Set (Capacity => C, Modulus => M) do
277
         Assign (Target => Target, Source => Source);
278
      end return;
279
   end Copy;
280
 
281
   ---------------------
282
   -- Default_Modulus --
283
   ---------------------
284
 
285
   function Default_Modulus (Capacity : Count_Type) return Hash_Type is
286
   begin
287
      return To_Prime (Capacity);
288
   end Default_Modulus;
289
 
290
   ------------
291
   -- Delete --
292
   ------------
293
 
294
   procedure Delete
295
     (Container : in out Set;
296
      Item      : Element_Type)
297
   is
298
      X : Count_Type;
299
 
300
   begin
301
      Element_Keys.Delete_Key_Sans_Free (Container, Item, X);
302
 
303
      if X = 0 then
304
         raise Constraint_Error with "attempt to delete element not in set";
305
      end if;
306
 
307
      HT_Ops.Free (Container, X);
308
   end Delete;
309
 
310
   procedure Delete
311
     (Container : in out Set;
312
      Position  : in out Cursor)
313
   is
314
   begin
315
      if Position.Node = 0 then
316
         raise Constraint_Error with "Position cursor equals No_Element";
317
      end if;
318
 
319
      if Position.Container /= Container'Unrestricted_Access then
320
         raise Program_Error with "Position cursor designates wrong set";
321
      end if;
322
 
323
      if Container.Busy > 0 then
324
         raise Program_Error with
325
           "attempt to tamper with cursors (set is busy)";
326
      end if;
327
 
328
      pragma Assert (Vet (Position), "bad cursor in Delete");
329
 
330
      HT_Ops.Delete_Node_Sans_Free (Container, Position.Node);
331
      HT_Ops.Free (Container, Position.Node);
332
 
333
      Position := No_Element;
334
   end Delete;
335
 
336
   ----------------
337
   -- Difference --
338
   ----------------
339
 
340
   procedure Difference
341
     (Target : in out Set;
342
      Source : Set)
343
   is
344
      Tgt_Node, Src_Node : Count_Type;
345
 
346
      TN : Nodes_Type renames Target.Nodes;
347
      SN : Nodes_Type renames Source.Nodes;
348
 
349
   begin
350
      if Target'Address = Source'Address then
351
         HT_Ops.Clear (Target);
352
         return;
353
      end if;
354
 
355
      if Source.Length = 0 then
356
         return;
357
      end if;
358
 
359
      if Target.Busy > 0 then
360
         raise Program_Error with
361
           "attempt to tamper with cursors (set is busy)";
362
      end if;
363
 
364
      if Source.Length < Target.Length then
365
         Src_Node := HT_Ops.First (Source);
366
         while Src_Node /= 0 loop
367
            Tgt_Node := Element_Keys.Find (Target, SN (Src_Node).Element);
368
 
369
            if Tgt_Node /= 0 then
370
               HT_Ops.Delete_Node_Sans_Free (Target, Tgt_Node);
371
               HT_Ops.Free (Target, Tgt_Node);
372
            end if;
373
 
374
            Src_Node := HT_Ops.Next (Source, Src_Node);
375
         end loop;
376
 
377
      else
378
         Tgt_Node := HT_Ops.First (Target);
379
         while Tgt_Node /= 0 loop
380
            if Is_In (Source, TN (Tgt_Node)) then
381
               declare
382
                  X : constant Count_Type := Tgt_Node;
383
               begin
384
                  Tgt_Node := HT_Ops.Next (Target, Tgt_Node);
385
                  HT_Ops.Delete_Node_Sans_Free (Target, X);
386
                  HT_Ops.Free (Target, X);
387
               end;
388
 
389
            else
390
               Tgt_Node := HT_Ops.Next (Target, Tgt_Node);
391
            end if;
392
         end loop;
393
      end if;
394
   end Difference;
395
 
396
   function Difference (Left, Right : Set) return Set is
397
   begin
398
      if Left'Address = Right'Address then
399
         return Empty_Set;
400
      end if;
401
 
402
      if Left.Length = 0 then
403
         return Empty_Set;
404
      end if;
405
 
406
      if Right.Length = 0 then
407
         return Left;
408
      end if;
409
 
410
      return Result : Set (Left.Length, To_Prime (Left.Length)) do
411
         Iterate_Left : declare
412
            procedure Process (L_Node : Count_Type);
413
 
414
            procedure Iterate is
415
               new HT_Ops.Generic_Iteration (Process);
416
 
417
            -------------
418
            -- Process --
419
            -------------
420
 
421
            procedure Process (L_Node : Count_Type) is
422
               N : Node_Type renames Left.Nodes (L_Node);
423
               X : Count_Type;
424
               B : Boolean;
425
            begin
426
               if not Is_In (Right, N) then
427
                  Insert (Result, N.Element, X, B);  --  optimize this ???
428
                  pragma Assert (B);
429
                  pragma Assert (X > 0);
430
               end if;
431
            end Process;
432
 
433
         --  Start of processing for Iterate_Left
434
 
435
         begin
436
            Iterate (Left);
437
         end Iterate_Left;
438
      end return;
439
   end Difference;
440
 
441
   -------------
442
   -- Element --
443
   -------------
444
 
445
   function Element (Position : Cursor) return Element_Type is
446
   begin
447
      if Position.Node = 0 then
448
         raise Constraint_Error with "Position cursor equals No_Element";
449
      end if;
450
 
451
      pragma Assert (Vet (Position), "bad cursor in function Element");
452
 
453
      declare
454
         S : Set renames Position.Container.all;
455
         N : Node_Type renames S.Nodes (Position.Node);
456
      begin
457
         return N.Element;
458
      end;
459
   end Element;
460
 
461
   ---------------------
462
   -- Equivalent_Sets --
463
   ---------------------
464
 
465
   function Equivalent_Sets (Left, Right : Set) return Boolean is
466
      function Find_Equivalent_Key
467
        (R_HT   : Hash_Table_Type'Class;
468
         L_Node : Node_Type) return Boolean;
469
      pragma Inline (Find_Equivalent_Key);
470
 
471
      function Is_Equivalent is
472
         new HT_Ops.Generic_Equal (Find_Equivalent_Key);
473
 
474
      -------------------------
475
      -- Find_Equivalent_Key --
476
      -------------------------
477
 
478
      function Find_Equivalent_Key
479
        (R_HT   : Hash_Table_Type'Class;
480
         L_Node : Node_Type) return Boolean
481
      is
482
         R_Index : constant Hash_Type :=
483
                     Element_Keys.Index (R_HT, L_Node.Element);
484
 
485
         R_Node  : Count_Type := R_HT.Buckets (R_Index);
486
 
487
         RN      : Nodes_Type renames R_HT.Nodes;
488
 
489
      begin
490
         loop
491
            if R_Node = 0 then
492
               return False;
493
            end if;
494
 
495
            if Equivalent_Elements (L_Node.Element, RN (R_Node).Element) then
496
               return True;
497
            end if;
498
 
499
            R_Node := HT_Ops.Next (R_HT, R_Node);
500
         end loop;
501
      end Find_Equivalent_Key;
502
 
503
   --  Start of processing for Equivalent_Sets
504
 
505
   begin
506
      return Is_Equivalent (Left, Right);
507
   end Equivalent_Sets;
508
 
509
   -------------------------
510
   -- Equivalent_Elements --
511
   -------------------------
512
 
513
   function Equivalent_Elements (Left, Right : Cursor)
514
     return Boolean is
515
 
516
   begin
517
      if Left.Node = 0 then
518
         raise Constraint_Error with
519
           "Left cursor of Equivalent_Elements equals No_Element";
520
      end if;
521
 
522
      if Right.Node = 0 then
523
         raise Constraint_Error with
524
           "Right cursor of Equivalent_Elements equals No_Element";
525
      end if;
526
 
527
      pragma Assert (Vet (Left), "bad Left cursor in Equivalent_Elements");
528
      pragma Assert (Vet (Right), "bad Right cursor in Equivalent_Elements");
529
 
530
      declare
531
         LN : Node_Type renames Left.Container.Nodes (Left.Node);
532
         RN : Node_Type renames Right.Container.Nodes (Right.Node);
533
      begin
534
         return Equivalent_Elements (LN.Element, RN.Element);
535
      end;
536
   end Equivalent_Elements;
537
 
538
   function Equivalent_Elements
539
     (Left  : Cursor;
540
      Right : Element_Type) return Boolean
541
   is
542
   begin
543
      if Left.Node = 0 then
544
         raise Constraint_Error with
545
           "Left cursor of Equivalent_Elements equals No_Element";
546
      end if;
547
 
548
      pragma Assert (Vet (Left), "Left cursor in Equivalent_Elements is bad");
549
 
550
      declare
551
         LN : Node_Type renames Left.Container.Nodes (Left.Node);
552
      begin
553
         return Equivalent_Elements (LN.Element, Right);
554
      end;
555
   end Equivalent_Elements;
556
 
557
   function Equivalent_Elements
558
     (Left  : Element_Type;
559
      Right : Cursor) return Boolean
560
   is
561
   begin
562
      if Right.Node = 0 then
563
         raise Constraint_Error with
564
           "Right cursor of Equivalent_Elements equals No_Element";
565
      end if;
566
 
567
      pragma Assert
568
        (Vet (Right),
569
         "Right cursor of Equivalent_Elements is bad");
570
 
571
      declare
572
         RN : Node_Type renames Right.Container.Nodes (Right.Node);
573
      begin
574
         return Equivalent_Elements (Left, RN.Element);
575
      end;
576
   end Equivalent_Elements;
577
 
578
   ---------------------
579
   -- Equivalent_Keys --
580
   ---------------------
581
 
582
   function Equivalent_Keys
583
     (Key  : Element_Type;
584
      Node : Node_Type) return Boolean
585
   is
586
   begin
587
      return Equivalent_Elements (Key, Node.Element);
588
   end Equivalent_Keys;
589
 
590
   -------------
591
   -- Exclude --
592
   -------------
593
 
594
   procedure Exclude
595
     (Container : in out Set;
596
      Item      : Element_Type)
597
   is
598
      X : Count_Type;
599
   begin
600
      Element_Keys.Delete_Key_Sans_Free (Container, Item, X);
601
      HT_Ops.Free (Container, X);
602
   end Exclude;
603
 
604
   --------------
605
   -- Finalize --
606
   --------------
607
 
608
   procedure Finalize (Object : in out Iterator) is
609
   begin
610
      if Object.Container /= null then
611
         declare
612
            B : Natural renames Object.Container.all.Busy;
613
         begin
614
            B := B - 1;
615
         end;
616
      end if;
617
   end Finalize;
618
 
619
   ----------
620
   -- Find --
621
   ----------
622
 
623
   function Find
624
     (Container : Set;
625
      Item      : Element_Type) return Cursor
626
   is
627
      Node : constant Count_Type := Element_Keys.Find (Container, Item);
628
   begin
629
      return (if Node = 0 then No_Element
630
              else Cursor'(Container'Unrestricted_Access, Node));
631
   end Find;
632
 
633
   -----------
634
   -- First --
635
   -----------
636
 
637
   function First (Container : Set) return Cursor is
638
      Node : constant Count_Type := HT_Ops.First (Container);
639
   begin
640
      return (if Node = 0 then No_Element
641
              else Cursor'(Container'Unrestricted_Access, Node));
642
   end First;
643
 
644
   overriding function First (Object : Iterator) return Cursor is
645
   begin
646
      return Object.Container.First;
647
   end First;
648
 
649
   -----------------
650
   -- Has_Element --
651
   -----------------
652
 
653
   function Has_Element (Position : Cursor) return Boolean is
654
   begin
655
      pragma Assert (Vet (Position), "bad cursor in Has_Element");
656
      return Position.Node /= 0;
657
   end Has_Element;
658
 
659
   ---------------
660
   -- Hash_Node --
661
   ---------------
662
 
663
   function Hash_Node (Node : Node_Type) return Hash_Type is
664
   begin
665
      return Hash (Node.Element);
666
   end Hash_Node;
667
 
668
   -------------
669
   -- Include --
670
   -------------
671
 
672
   procedure Include
673
     (Container : in out Set;
674
      New_Item  : Element_Type)
675
   is
676
      Position : Cursor;
677
      Inserted : Boolean;
678
 
679
   begin
680
      Insert (Container, New_Item, Position, Inserted);
681
 
682
      if not Inserted then
683
         if Container.Lock > 0 then
684
            raise Program_Error with
685
              "attempt to tamper with elements (set is locked)";
686
         end if;
687
 
688
         Container.Nodes (Position.Node).Element := New_Item;
689
      end if;
690
   end Include;
691
 
692
   ------------
693
   -- Insert --
694
   ------------
695
 
696
   procedure Insert
697
     (Container : in out Set;
698
      New_Item  : Element_Type;
699
      Position  : out Cursor;
700
      Inserted  : out Boolean)
701
   is
702
   begin
703
      Insert (Container, New_Item, Position.Node, Inserted);
704
      Position.Container := Container'Unchecked_Access;
705
   end Insert;
706
 
707
   procedure Insert
708
     (Container : in out Set;
709
      New_Item  : Element_Type)
710
   is
711
      Position : Cursor;
712
      pragma Unreferenced (Position);
713
 
714
      Inserted : Boolean;
715
 
716
   begin
717
      Insert (Container, New_Item, Position, Inserted);
718
 
719
      if not Inserted then
720
         raise Constraint_Error with
721
           "attempt to insert element already in set";
722
      end if;
723
   end Insert;
724
 
725
   procedure Insert
726
     (Container : in out Set;
727
      New_Item  : Element_Type;
728
      Node      : out Count_Type;
729
      Inserted  : out Boolean)
730
   is
731
      procedure Allocate_Set_Element (Node : in out Node_Type);
732
      pragma Inline (Allocate_Set_Element);
733
 
734
      function New_Node return Count_Type;
735
      pragma Inline (New_Node);
736
 
737
      procedure Local_Insert is
738
        new Element_Keys.Generic_Conditional_Insert (New_Node);
739
 
740
      procedure Allocate is
741
         new HT_Ops.Generic_Allocate (Allocate_Set_Element);
742
 
743
      ---------------------------
744
      --  Allocate_Set_Element --
745
      ---------------------------
746
 
747
      procedure Allocate_Set_Element (Node : in out Node_Type) is
748
      begin
749
         Node.Element := New_Item;
750
      end Allocate_Set_Element;
751
 
752
      --------------
753
      -- New_Node --
754
      --------------
755
 
756
      function New_Node return Count_Type is
757
         Result : Count_Type;
758
      begin
759
         Allocate (Container, Result);
760
         return Result;
761
      end New_Node;
762
 
763
   --  Start of processing for Insert
764
 
765
   begin
766
      --  The buckets array length is specified by the user as a discriminant
767
      --  of the container type, so it is possible for the buckets array to
768
      --  have a length of zero. We must check for this case specifically, in
769
      --  order to prevent divide-by-zero errors later, when we compute the
770
      --  buckets array index value for an element, given its hash value.
771
 
772
      if Container.Buckets'Length = 0 then
773
         raise Capacity_Error with "No capacity for insertion";
774
      end if;
775
 
776
      Local_Insert (Container, New_Item, Node, Inserted);
777
   end Insert;
778
 
779
   ------------------
780
   -- Intersection --
781
   ------------------
782
 
783
   procedure Intersection
784
     (Target : in out Set;
785
      Source : Set)
786
   is
787
      Tgt_Node : Count_Type;
788
      TN       : Nodes_Type renames Target.Nodes;
789
 
790
   begin
791
      if Target'Address = Source'Address then
792
         return;
793
      end if;
794
 
795
      if Source.Length = 0 then
796
         HT_Ops.Clear (Target);
797
         return;
798
      end if;
799
 
800
      if Target.Busy > 0 then
801
         raise Program_Error with
802
           "attempt to tamper with cursors (set is busy)";
803
      end if;
804
 
805
      Tgt_Node := HT_Ops.First (Target);
806
      while Tgt_Node /= 0 loop
807
         if Is_In (Source, TN (Tgt_Node)) then
808
            Tgt_Node := HT_Ops.Next (Target, Tgt_Node);
809
 
810
         else
811
            declare
812
               X : constant Count_Type := Tgt_Node;
813
            begin
814
               Tgt_Node := HT_Ops.Next (Target, Tgt_Node);
815
               HT_Ops.Delete_Node_Sans_Free (Target, X);
816
               HT_Ops.Free (Target, X);
817
            end;
818
         end if;
819
      end loop;
820
   end Intersection;
821
 
822
   function Intersection (Left, Right : Set) return Set is
823
      C : Count_Type;
824
 
825
   begin
826
      if Left'Address = Right'Address then
827
         return Left;
828
      end if;
829
 
830
      C := Count_Type'Min (Left.Length, Right.Length);
831
 
832
      if C = 0 then
833
         return Empty_Set;
834
      end if;
835
 
836
      return Result : Set (C, To_Prime (C)) do
837
         Iterate_Left : declare
838
            procedure Process (L_Node : Count_Type);
839
 
840
            procedure Iterate is
841
               new HT_Ops.Generic_Iteration (Process);
842
 
843
            -------------
844
            -- Process --
845
            -------------
846
 
847
            procedure Process (L_Node : Count_Type) is
848
               N : Node_Type renames Left.Nodes (L_Node);
849
               X : Count_Type;
850
               B : Boolean;
851
 
852
            begin
853
               if Is_In (Right, N) then
854
                  Insert (Result, N.Element, X, B);  -- optimize ???
855
                  pragma Assert (B);
856
                  pragma Assert (X > 0);
857
               end if;
858
            end Process;
859
 
860
         --  Start of processing for Iterate_Left
861
 
862
         begin
863
            Iterate (Left);
864
         end Iterate_Left;
865
      end return;
866
   end Intersection;
867
 
868
   --------------
869
   -- Is_Empty --
870
   --------------
871
 
872
   function Is_Empty (Container : Set) return Boolean is
873
   begin
874
      return Container.Length = 0;
875
   end Is_Empty;
876
 
877
   -----------
878
   -- Is_In --
879
   -----------
880
 
881
   function Is_In (HT : Set; Key : Node_Type) return Boolean is
882
   begin
883
      return Element_Keys.Find (HT, Key.Element) /= 0;
884
   end Is_In;
885
 
886
   ---------------
887
   -- Is_Subset --
888
   ---------------
889
 
890
   function Is_Subset (Subset : Set; Of_Set : Set) return Boolean is
891
      Subset_Node : Count_Type;
892
      SN          : Nodes_Type renames Subset.Nodes;
893
 
894
   begin
895
      if Subset'Address = Of_Set'Address then
896
         return True;
897
      end if;
898
 
899
      if Subset.Length > Of_Set.Length then
900
         return False;
901
      end if;
902
 
903
      Subset_Node := HT_Ops.First (Subset);
904
      while Subset_Node /= 0 loop
905
         if not Is_In (Of_Set, SN (Subset_Node)) then
906
            return False;
907
         end if;
908
         Subset_Node := HT_Ops.Next (Subset, Subset_Node);
909
      end loop;
910
 
911
      return True;
912
   end Is_Subset;
913
 
914
   -------------
915
   -- Iterate --
916
   -------------
917
 
918
   procedure Iterate
919
     (Container : Set;
920
      Process   : not null access procedure (Position : Cursor))
921
   is
922
      procedure Process_Node (Node : Count_Type);
923
      pragma Inline (Process_Node);
924
 
925
      procedure Iterate is
926
         new HT_Ops.Generic_Iteration (Process_Node);
927
 
928
      ------------------
929
      -- Process_Node --
930
      ------------------
931
 
932
      procedure Process_Node (Node : Count_Type) is
933
      begin
934
         Process (Cursor'(Container'Unrestricted_Access, Node));
935
      end Process_Node;
936
 
937
      B : Natural renames Container'Unrestricted_Access.all.Busy;
938
 
939
   --  Start of processing for Iterate
940
 
941
   begin
942
      B := B + 1;
943
 
944
      begin
945
         Iterate (Container);
946
      exception
947
         when others =>
948
            B := B - 1;
949
            raise;
950
      end;
951
 
952
      B := B - 1;
953
   end Iterate;
954
 
955
   function Iterate (Container : Set)
956
     return Set_Iterator_Interfaces.Forward_Iterator'Class
957
   is
958
      B : Natural renames Container'Unrestricted_Access.all.Busy;
959
   begin
960
      B := B + 1;
961
      return It : constant Iterator :=
962
                    Iterator'(Limited_Controlled with
963
                                Container => Container'Unrestricted_Access);
964
   end Iterate;
965
 
966
   ------------
967
   -- Length --
968
   ------------
969
 
970
   function Length (Container : Set) return Count_Type is
971
   begin
972
      return Container.Length;
973
   end Length;
974
 
975
   ----------
976
   -- Move --
977
   ----------
978
 
979
   procedure Move (Target : in out Set; Source : in out Set) is
980
   begin
981
      if Target'Address = Source'Address then
982
         return;
983
      end if;
984
 
985
      if Source.Busy > 0 then
986
         raise Program_Error with
987
           "attempt to tamper with cursors (container is busy)";
988
      end if;
989
 
990
      Target.Assign (Source);
991
      Source.Clear;
992
   end Move;
993
 
994
   ----------
995
   -- Next --
996
   ----------
997
 
998
   function Next (Node : Node_Type) return Count_Type is
999
   begin
1000
      return Node.Next;
1001
   end Next;
1002
 
1003
   function Next (Position : Cursor) return Cursor is
1004
   begin
1005
      if Position.Node = 0 then
1006
         return No_Element;
1007
      end if;
1008
 
1009
      pragma Assert (Vet (Position), "bad cursor in Next");
1010
 
1011
      declare
1012
         HT   : Set renames Position.Container.all;
1013
         Node : constant Count_Type := HT_Ops.Next (HT, Position.Node);
1014
 
1015
      begin
1016
         if Node = 0 then
1017
            return No_Element;
1018
         end if;
1019
 
1020
         return Cursor'(Position.Container, Node);
1021
      end;
1022
   end Next;
1023
 
1024
   procedure Next (Position : in out Cursor) is
1025
   begin
1026
      Position := Next (Position);
1027
   end Next;
1028
 
1029
   function Next
1030
     (Object : Iterator;
1031
      Position : Cursor) return Cursor
1032
   is
1033
   begin
1034
      if Position.Container = null then
1035
         return No_Element;
1036
      end if;
1037
 
1038
      if Position.Container /= Object.Container then
1039
         raise Program_Error with
1040
           "Position cursor of Next designates wrong set";
1041
      end if;
1042
 
1043
      return Next (Position);
1044
   end Next;
1045
 
1046
   -------------
1047
   -- Overlap --
1048
   -------------
1049
 
1050
   function Overlap (Left, Right : Set) return Boolean is
1051
      Left_Node : Count_Type;
1052
 
1053
   begin
1054
      if Right.Length = 0 then
1055
         return False;
1056
      end if;
1057
 
1058
      if Left'Address = Right'Address then
1059
         return True;
1060
      end if;
1061
 
1062
      Left_Node := HT_Ops.First (Left);
1063
      while Left_Node /= 0 loop
1064
         if Is_In (Right, Left.Nodes (Left_Node)) then
1065
            return True;
1066
         end if;
1067
         Left_Node := HT_Ops.Next (Left, Left_Node);
1068
      end loop;
1069
 
1070
      return False;
1071
   end Overlap;
1072
 
1073
   -------------------
1074
   -- Query_Element --
1075
   -------------------
1076
 
1077
   procedure Query_Element
1078
     (Position : Cursor;
1079
      Process  : not null access procedure (Element : Element_Type))
1080
   is
1081
   begin
1082
      if Position.Node = 0 then
1083
         raise Constraint_Error with
1084
           "Position cursor of Query_Element equals No_Element";
1085
      end if;
1086
 
1087
      pragma Assert (Vet (Position), "bad cursor in Query_Element");
1088
 
1089
      declare
1090
         S : Set renames Position.Container.all;
1091
         B : Natural renames S.Busy;
1092
         L : Natural renames S.Lock;
1093
 
1094
      begin
1095
         B := B + 1;
1096
         L := L + 1;
1097
 
1098
         begin
1099
            Process (S.Nodes (Position.Node).Element);
1100
         exception
1101
            when others =>
1102
               L := L - 1;
1103
               B := B - 1;
1104
               raise;
1105
         end;
1106
 
1107
         L := L - 1;
1108
         B := B - 1;
1109
      end;
1110
   end Query_Element;
1111
 
1112
   ----------
1113
   -- Read --
1114
   ----------
1115
 
1116
   procedure Read
1117
     (Stream    : not null access Root_Stream_Type'Class;
1118
      Container : out Set)
1119
   is
1120
      function Read_Node (Stream : not null access Root_Stream_Type'Class)
1121
        return Count_Type;
1122
 
1123
      procedure Read_Nodes is
1124
         new HT_Ops.Generic_Read (Read_Node);
1125
 
1126
      ---------------
1127
      -- Read_Node --
1128
      ---------------
1129
 
1130
      function Read_Node (Stream : not null access Root_Stream_Type'Class)
1131
        return Count_Type
1132
      is
1133
         procedure Read_Element (Node : in out Node_Type);
1134
         pragma Inline (Read_Element);
1135
 
1136
         procedure Allocate is
1137
            new HT_Ops.Generic_Allocate (Read_Element);
1138
 
1139
         procedure Read_Element (Node : in out Node_Type) is
1140
         begin
1141
            Element_Type'Read (Stream, Node.Element);
1142
         end Read_Element;
1143
 
1144
         Node : Count_Type;
1145
 
1146
      --  Start of processing for Read_Node
1147
 
1148
      begin
1149
         Allocate (Container, Node);
1150
         return Node;
1151
      end Read_Node;
1152
 
1153
   --  Start of processing for Read
1154
 
1155
   begin
1156
      Read_Nodes (Stream, Container);
1157
   end Read;
1158
 
1159
   procedure Read
1160
     (Stream : not null access Root_Stream_Type'Class;
1161
      Item   : out Cursor)
1162
   is
1163
   begin
1164
      raise Program_Error with "attempt to stream set cursor";
1165
   end Read;
1166
 
1167
   procedure Read
1168
     (Stream : not null access Root_Stream_Type'Class;
1169
      Item   : out Constant_Reference_Type)
1170
   is
1171
   begin
1172
      raise Program_Error with "attempt to stream reference";
1173
   end Read;
1174
 
1175
   -------------
1176
   -- Replace --
1177
   -------------
1178
 
1179
   procedure Replace
1180
     (Container : in out Set;
1181
      New_Item  : Element_Type)
1182
   is
1183
      Node : constant Count_Type :=
1184
               Element_Keys.Find (Container, New_Item);
1185
 
1186
   begin
1187
      if Node = 0 then
1188
         raise Constraint_Error with
1189
           "attempt to replace element not in set";
1190
      end if;
1191
 
1192
      if Container.Lock > 0 then
1193
         raise Program_Error with
1194
           "attempt to tamper with elements (set is locked)";
1195
      end if;
1196
 
1197
      Container.Nodes (Node).Element := New_Item;
1198
   end Replace;
1199
 
1200
   procedure Replace_Element
1201
     (Container : in out Set;
1202
      Position  : Cursor;
1203
      New_Item  : Element_Type)
1204
   is
1205
   begin
1206
      if Position.Node = 0 then
1207
         raise Constraint_Error with
1208
           "Position cursor equals No_Element";
1209
      end if;
1210
 
1211
      if Position.Container /= Container'Unrestricted_Access then
1212
         raise Program_Error with
1213
           "Position cursor designates wrong set";
1214
      end if;
1215
 
1216
      pragma Assert (Vet (Position), "bad cursor in Replace_Element");
1217
 
1218
      Replace_Element (Container, Position.Node, New_Item);
1219
   end Replace_Element;
1220
 
1221
   ----------------------
1222
   -- Reserve_Capacity --
1223
   ----------------------
1224
 
1225
   procedure Reserve_Capacity
1226
     (Container : in out Set;
1227
      Capacity  : Count_Type)
1228
   is
1229
   begin
1230
      if Capacity > Container.Capacity then
1231
         raise Capacity_Error with "requested capacity is too large";
1232
      end if;
1233
   end Reserve_Capacity;
1234
 
1235
   ------------------
1236
   --  Set_Element --
1237
   ------------------
1238
 
1239
   procedure Set_Element (Node : in out Node_Type; Item : Element_Type) is
1240
   begin
1241
      Node.Element := Item;
1242
   end Set_Element;
1243
 
1244
   --------------
1245
   -- Set_Next --
1246
   --------------
1247
 
1248
   procedure Set_Next (Node : in out Node_Type; Next : Count_Type) is
1249
   begin
1250
      Node.Next := Next;
1251
   end Set_Next;
1252
 
1253
   --------------------------
1254
   -- Symmetric_Difference --
1255
   --------------------------
1256
 
1257
   procedure Symmetric_Difference
1258
     (Target : in out Set;
1259
      Source : Set)
1260
   is
1261
      procedure Process (Source_Node : Count_Type);
1262
      pragma Inline (Process);
1263
 
1264
      procedure Iterate is
1265
         new HT_Ops.Generic_Iteration (Process);
1266
 
1267
      -------------
1268
      -- Process --
1269
      -------------
1270
 
1271
      procedure Process (Source_Node : Count_Type) is
1272
         N : Node_Type renames Source.Nodes (Source_Node);
1273
         X : Count_Type;
1274
         B : Boolean;
1275
 
1276
      begin
1277
         if Is_In (Target, N) then
1278
            Delete (Target, N.Element);
1279
         else
1280
            Insert (Target, N.Element, X, B);
1281
            pragma Assert (B);
1282
         end if;
1283
      end Process;
1284
 
1285
   --  Start of processing for Symmetric_Difference
1286
 
1287
   begin
1288
      if Target'Address = Source'Address then
1289
         HT_Ops.Clear (Target);
1290
         return;
1291
      end if;
1292
 
1293
      if Target.Length = 0 then
1294
         Assign (Target => Target, Source => Source);
1295
         return;
1296
      end if;
1297
 
1298
      if Target.Busy > 0 then
1299
         raise Program_Error with
1300
           "attempt to tamper with cursors (set is busy)";
1301
      end if;
1302
 
1303
      Iterate (Source);
1304
   end Symmetric_Difference;
1305
 
1306
   function Symmetric_Difference (Left, Right : Set) return Set is
1307
      C : Count_Type;
1308
 
1309
   begin
1310
      if Left'Address = Right'Address then
1311
         return Empty_Set;
1312
      end if;
1313
 
1314
      if Right.Length = 0 then
1315
         return Left;
1316
      end if;
1317
 
1318
      if Left.Length = 0 then
1319
         return Right;
1320
      end if;
1321
 
1322
      C := Left.Length + Right.Length;
1323
 
1324
      return Result : Set (C, To_Prime (C)) do
1325
         Iterate_Left : declare
1326
            procedure Process (L_Node : Count_Type);
1327
 
1328
            procedure Iterate is
1329
               new HT_Ops.Generic_Iteration (Process);
1330
 
1331
            -------------
1332
            -- Process --
1333
            -------------
1334
 
1335
            procedure Process (L_Node : Count_Type) is
1336
               N : Node_Type renames Left.Nodes (L_Node);
1337
               X : Count_Type;
1338
               B : Boolean;
1339
            begin
1340
               if not Is_In (Right, N) then
1341
                  Insert (Result, N.Element, X, B);
1342
                  pragma Assert (B);
1343
               end if;
1344
            end Process;
1345
 
1346
         --  Start of processing for Iterate_Left
1347
 
1348
         begin
1349
            Iterate (Left);
1350
         end Iterate_Left;
1351
 
1352
         Iterate_Right : declare
1353
            procedure Process (R_Node : Count_Type);
1354
 
1355
            procedure Iterate is
1356
               new HT_Ops.Generic_Iteration (Process);
1357
 
1358
            -------------
1359
            -- Process --
1360
            -------------
1361
 
1362
            procedure Process (R_Node : Count_Type) is
1363
               N : Node_Type renames Right.Nodes (R_Node);
1364
               X : Count_Type;
1365
               B : Boolean;
1366
            begin
1367
               if not Is_In (Left, N) then
1368
                  Insert (Result, N.Element, X, B);
1369
                  pragma Assert (B);
1370
               end if;
1371
            end Process;
1372
 
1373
         --  Start of processing for Iterate_Right
1374
 
1375
         begin
1376
            Iterate (Right);
1377
         end Iterate_Right;
1378
      end return;
1379
   end Symmetric_Difference;
1380
 
1381
   ------------
1382
   -- To_Set --
1383
   ------------
1384
 
1385
   function To_Set (New_Item : Element_Type) return Set is
1386
      X : Count_Type;
1387
      B : Boolean;
1388
   begin
1389
      return Result : Set (1, 1) do
1390
         Insert (Result, New_Item, X, B);
1391
         pragma Assert (B);
1392
      end return;
1393
   end To_Set;
1394
 
1395
   -----------
1396
   -- Union --
1397
   -----------
1398
 
1399
   procedure Union
1400
     (Target : in out Set;
1401
      Source : Set)
1402
   is
1403
      procedure Process (Src_Node : Count_Type);
1404
 
1405
      procedure Iterate is
1406
         new HT_Ops.Generic_Iteration (Process);
1407
 
1408
      -------------
1409
      -- Process --
1410
      -------------
1411
 
1412
      procedure Process (Src_Node : Count_Type) is
1413
         N : Node_Type renames Source.Nodes (Src_Node);
1414
         X : Count_Type;
1415
         B : Boolean;
1416
      begin
1417
         Insert (Target, N.Element, X, B);
1418
      end Process;
1419
 
1420
   --  Start of processing for Union
1421
 
1422
   begin
1423
      if Target'Address = Source'Address then
1424
         return;
1425
      end if;
1426
 
1427
      if Target.Busy > 0 then
1428
         raise Program_Error with
1429
           "attempt to tamper with cursors (set is busy)";
1430
      end if;
1431
 
1432
      --  ??? why is this code commented out ???
1433
      --  declare
1434
      --     N : constant Count_Type := Target.Length + Source.Length;
1435
      --  begin
1436
      --     if N > HT_Ops.Capacity (Target.HT) then
1437
      --        HT_Ops.Reserve_Capacity (Target.HT, N);
1438
      --     end if;
1439
      --  end;
1440
 
1441
      Iterate (Source);
1442
   end Union;
1443
 
1444
   function Union (Left, Right : Set) return Set is
1445
      C : Count_Type;
1446
 
1447
   begin
1448
      if Left'Address = Right'Address then
1449
         return Left;
1450
      end if;
1451
 
1452
      if Right.Length = 0 then
1453
         return Left;
1454
      end if;
1455
 
1456
      if Left.Length = 0 then
1457
         return Right;
1458
      end if;
1459
 
1460
      C := Left.Length + Right.Length;
1461
 
1462
      return Result : Set (C, To_Prime (C)) do
1463
         Assign (Target => Result, Source => Left);
1464
         Union (Target => Result, Source => Right);
1465
      end return;
1466
   end Union;
1467
 
1468
   ---------
1469
   -- Vet --
1470
   ---------
1471
 
1472
   function Vet (Position : Cursor) return Boolean is
1473
   begin
1474
      if Position.Node = 0 then
1475
         return Position.Container = null;
1476
      end if;
1477
 
1478
      if Position.Container = null then
1479
         return False;
1480
      end if;
1481
 
1482
      declare
1483
         S : Set renames Position.Container.all;
1484
         N : Nodes_Type renames S.Nodes;
1485
         X : Count_Type;
1486
 
1487
      begin
1488
         if S.Length = 0 then
1489
            return False;
1490
         end if;
1491
 
1492
         if Position.Node > N'Last then
1493
            return False;
1494
         end if;
1495
 
1496
         if N (Position.Node).Next = Position.Node then
1497
            return False;
1498
         end if;
1499
 
1500
         X := S.Buckets (Element_Keys.Index (S, N (Position.Node).Element));
1501
 
1502
         for J in 1 .. S.Length loop
1503
            if X = Position.Node then
1504
               return True;
1505
            end if;
1506
 
1507
            if X = 0 then
1508
               return False;
1509
            end if;
1510
 
1511
            if X = N (X).Next then  --  to prevent unnecessary looping
1512
               return False;
1513
            end if;
1514
 
1515
            X := N (X).Next;
1516
         end loop;
1517
 
1518
         return False;
1519
      end;
1520
   end Vet;
1521
 
1522
   -----------
1523
   -- Write --
1524
   -----------
1525
 
1526
   procedure Write
1527
     (Stream    : not null access Root_Stream_Type'Class;
1528
      Container : Set)
1529
   is
1530
      procedure Write_Node
1531
        (Stream : not null access Root_Stream_Type'Class;
1532
         Node   : Node_Type);
1533
      pragma Inline (Write_Node);
1534
 
1535
      procedure Write_Nodes is
1536
         new HT_Ops.Generic_Write (Write_Node);
1537
 
1538
      ----------------
1539
      -- Write_Node --
1540
      ----------------
1541
 
1542
      procedure Write_Node
1543
        (Stream : not null access Root_Stream_Type'Class;
1544
         Node   : Node_Type)
1545
      is
1546
      begin
1547
         Element_Type'Write (Stream, Node.Element);
1548
      end Write_Node;
1549
 
1550
   --  Start of processing for Write
1551
 
1552
   begin
1553
      Write_Nodes (Stream, Container);
1554
   end Write;
1555
 
1556
   procedure Write
1557
     (Stream : not null access Root_Stream_Type'Class;
1558
      Item   : Cursor)
1559
   is
1560
   begin
1561
      raise Program_Error with "attempt to stream set cursor";
1562
   end Write;
1563
 
1564
   procedure Write
1565
     (Stream : not null access Root_Stream_Type'Class;
1566
      Item   : Constant_Reference_Type)
1567
   is
1568
   begin
1569
      raise Program_Error with "attempt to stream reference";
1570
   end Write;
1571
 
1572
   package body Generic_Keys is
1573
 
1574
      -----------------------
1575
      -- Local Subprograms --
1576
      -----------------------
1577
 
1578
      function Equivalent_Key_Node
1579
        (Key  : Key_Type;
1580
         Node : Node_Type) return Boolean;
1581
      pragma Inline (Equivalent_Key_Node);
1582
 
1583
      --------------------------
1584
      -- Local Instantiations --
1585
      --------------------------
1586
 
1587
      package Key_Keys is
1588
         new Hash_Tables.Generic_Bounded_Keys
1589
          (HT_Types  => HT_Types,
1590
           Next      => Next,
1591
           Set_Next  => Set_Next,
1592
           Key_Type  => Key_Type,
1593
           Hash      => Hash,
1594
           Equivalent_Keys => Equivalent_Key_Node);
1595
 
1596
      ------------------------
1597
      -- Constant_Reference --
1598
      ------------------------
1599
 
1600
      function Constant_Reference
1601
        (Container : aliased Set;
1602
         Key       : Key_Type) return Constant_Reference_Type
1603
      is
1604
         Node : constant Count_Type := Key_Keys.Find (Container, Key);
1605
 
1606
      begin
1607
         if Node = 0 then
1608
            raise Constraint_Error with "key not in set";
1609
         end if;
1610
 
1611
         declare
1612
            N : Node_Type renames Container.Nodes (Node);
1613
         begin
1614
            return (Element => N.Element'Access);
1615
         end;
1616
      end Constant_Reference;
1617
 
1618
      --------------
1619
      -- Contains --
1620
      --------------
1621
 
1622
      function Contains
1623
        (Container : Set;
1624
         Key       : Key_Type) return Boolean
1625
      is
1626
      begin
1627
         return Find (Container, Key) /= No_Element;
1628
      end Contains;
1629
 
1630
      ------------
1631
      -- Delete --
1632
      ------------
1633
 
1634
      procedure Delete
1635
        (Container : in out Set;
1636
         Key       : Key_Type)
1637
      is
1638
         X : Count_Type;
1639
 
1640
      begin
1641
         Key_Keys.Delete_Key_Sans_Free (Container, Key, X);
1642
 
1643
         if X = 0 then
1644
            raise Constraint_Error with "attempt to delete key not in set";
1645
         end if;
1646
 
1647
         HT_Ops.Free (Container, X);
1648
      end Delete;
1649
 
1650
      -------------
1651
      -- Element --
1652
      -------------
1653
 
1654
      function Element
1655
        (Container : Set;
1656
         Key       : Key_Type) return Element_Type
1657
      is
1658
         Node : constant Count_Type := Key_Keys.Find (Container, Key);
1659
 
1660
      begin
1661
         if Node = 0 then
1662
            raise Constraint_Error with "key not in map";  --  ??? "set"
1663
         end if;
1664
 
1665
         return Container.Nodes (Node).Element;
1666
      end Element;
1667
 
1668
      -------------------------
1669
      -- Equivalent_Key_Node --
1670
      -------------------------
1671
 
1672
      function Equivalent_Key_Node
1673
        (Key  : Key_Type;
1674
         Node : Node_Type) return Boolean
1675
      is
1676
      begin
1677
         return Equivalent_Keys (Key, Generic_Keys.Key (Node.Element));
1678
      end Equivalent_Key_Node;
1679
 
1680
      -------------
1681
      -- Exclude --
1682
      -------------
1683
 
1684
      procedure Exclude
1685
        (Container : in out Set;
1686
         Key       : Key_Type)
1687
      is
1688
         X : Count_Type;
1689
      begin
1690
         Key_Keys.Delete_Key_Sans_Free (Container, Key, X);
1691
         HT_Ops.Free (Container, X);
1692
      end Exclude;
1693
 
1694
      ----------
1695
      -- Find --
1696
      ----------
1697
 
1698
      function Find
1699
        (Container : Set;
1700
         Key       : Key_Type) return Cursor
1701
      is
1702
         Node : constant Count_Type := Key_Keys.Find (Container, Key);
1703
      begin
1704
         return (if Node = 0 then No_Element
1705
                 else Cursor'(Container'Unrestricted_Access, Node));
1706
      end Find;
1707
 
1708
      ---------
1709
      -- Key --
1710
      ---------
1711
 
1712
      function Key (Position : Cursor) return Key_Type is
1713
      begin
1714
         if Position.Node = 0 then
1715
            raise Constraint_Error with
1716
              "Position cursor equals No_Element";
1717
         end if;
1718
 
1719
         pragma Assert (Vet (Position), "bad cursor in function Key");
1720
         return Key (Position.Container.Nodes (Position.Node).Element);
1721
      end Key;
1722
 
1723
      ----------
1724
      -- Read --
1725
      ----------
1726
 
1727
      procedure  Read
1728
        (Stream : not null access Root_Stream_Type'Class;
1729
         Item   : out Reference_Type)
1730
      is
1731
      begin
1732
         raise Program_Error with "attempt to stream reference";
1733
      end Read;
1734
 
1735
      ------------------------------
1736
      -- Reference_Preserving_Key --
1737
      ------------------------------
1738
 
1739
      function Reference_Preserving_Key
1740
        (Container : aliased in out Set;
1741
         Position  : Cursor) return Reference_Type
1742
      is
1743
      begin
1744
         if Position.Container = null then
1745
            raise Constraint_Error with "Position cursor has no element";
1746
         end if;
1747
 
1748
         if Position.Container /= Container'Unrestricted_Access then
1749
            raise Program_Error with
1750
              "Position cursor designates wrong container";
1751
         end if;
1752
 
1753
         pragma Assert
1754
           (Vet (Position),
1755
            "bad cursor in function Reference_Preserving_Key");
1756
 
1757
         --  Some form of finalization will be required in order to actually
1758
         --  check that the key-part of the element designated by Position has
1759
         --  not changed.  ???
1760
 
1761
         declare
1762
            N : Node_Type renames Container.Nodes (Position.Node);
1763
         begin
1764
            return (Element => N.Element'Access);
1765
         end;
1766
      end Reference_Preserving_Key;
1767
 
1768
      function Reference_Preserving_Key
1769
        (Container : aliased in out Set;
1770
         Key       : Key_Type) return Reference_Type
1771
      is
1772
         Node : constant Count_Type := Key_Keys.Find (Container, Key);
1773
 
1774
      begin
1775
         if Node = 0 then
1776
            raise Constraint_Error with "key not in set";
1777
         end if;
1778
 
1779
         declare
1780
            N : Node_Type renames Container.Nodes (Node);
1781
         begin
1782
            return (Element => N.Element'Access);
1783
         end;
1784
      end Reference_Preserving_Key;
1785
 
1786
      -------------
1787
      -- Replace --
1788
      -------------
1789
 
1790
      procedure Replace
1791
        (Container : in out Set;
1792
         Key       : Key_Type;
1793
         New_Item  : Element_Type)
1794
      is
1795
         Node : constant Count_Type := Key_Keys.Find (Container, Key);
1796
 
1797
      begin
1798
         if Node = 0 then
1799
            raise Constraint_Error with
1800
              "attempt to replace key not in set";
1801
         end if;
1802
 
1803
         Replace_Element (Container, Node, New_Item);
1804
      end Replace;
1805
 
1806
      -----------------------------------
1807
      -- Update_Element_Preserving_Key --
1808
      -----------------------------------
1809
 
1810
      procedure Update_Element_Preserving_Key
1811
        (Container : in out Set;
1812
         Position  : Cursor;
1813
         Process   : not null access
1814
                       procedure (Element : in out Element_Type))
1815
      is
1816
         Indx : Hash_Type;
1817
         N    : Nodes_Type renames Container.Nodes;
1818
 
1819
      begin
1820
         if Position.Node = 0 then
1821
            raise Constraint_Error with
1822
              "Position cursor equals No_Element";
1823
         end if;
1824
 
1825
         if Position.Container /= Container'Unrestricted_Access then
1826
            raise Program_Error with
1827
              "Position cursor designates wrong set";
1828
         end if;
1829
 
1830
         --  ??? why is this code commented out ???
1831
         --  if HT.Buckets = null
1832
         --    or else HT.Buckets'Length = 0
1833
         --    or else HT.Length = 0
1834
         --    or else Position.Node.Next = Position.Node
1835
         --  then
1836
         --     raise Program_Error with
1837
         --        "Position cursor is bad (set is empty)";
1838
         --  end if;
1839
 
1840
         pragma Assert
1841
           (Vet (Position),
1842
            "bad cursor in Update_Element_Preserving_Key");
1843
 
1844
         --  Record bucket now, in case key is changed
1845
 
1846
         Indx := HT_Ops.Index (Container.Buckets, N (Position.Node));
1847
 
1848
         declare
1849
            E : Element_Type renames N (Position.Node).Element;
1850
            K : constant Key_Type := Key (E);
1851
 
1852
            B : Natural renames Container.Busy;
1853
            L : Natural renames Container.Lock;
1854
 
1855
         begin
1856
            B := B + 1;
1857
            L := L + 1;
1858
 
1859
            begin
1860
               Process (E);
1861
            exception
1862
               when others =>
1863
                  L := L - 1;
1864
                  B := B - 1;
1865
                  raise;
1866
            end;
1867
 
1868
            L := L - 1;
1869
            B := B - 1;
1870
 
1871
            if Equivalent_Keys (K, Key (E)) then
1872
               pragma Assert (Hash (K) = Hash (E));
1873
               return;
1874
            end if;
1875
         end;
1876
 
1877
         --  Key was modified, so remove this node from set.
1878
 
1879
         if Container.Buckets (Indx) = Position.Node then
1880
            Container.Buckets (Indx) := N (Position.Node).Next;
1881
 
1882
         else
1883
            declare
1884
               Prev : Count_Type := Container.Buckets (Indx);
1885
 
1886
            begin
1887
               while N (Prev).Next /= Position.Node loop
1888
                  Prev := N (Prev).Next;
1889
 
1890
                  if Prev = 0 then
1891
                     raise Program_Error with
1892
                       "Position cursor is bad (node not found)";
1893
                  end if;
1894
               end loop;
1895
 
1896
               N (Prev).Next := N (Position.Node).Next;
1897
            end;
1898
         end if;
1899
 
1900
         Container.Length := Container.Length - 1;
1901
         HT_Ops.Free (Container, Position.Node);
1902
 
1903
         raise Program_Error with "key was modified";
1904
      end Update_Element_Preserving_Key;
1905
 
1906
      -----------
1907
      -- Write --
1908
      -----------
1909
 
1910
      procedure Write
1911
        (Stream : not null access Root_Stream_Type'Class;
1912
         Item   : Reference_Type)
1913
      is
1914
      begin
1915
         raise Program_Error with "attempt to stream reference";
1916
      end Write;
1917
 
1918
   end Generic_Keys;
1919
 
1920
end Ada.Containers.Bounded_Hashed_Sets;

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