1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT LIBRARY COMPONENTS                          --
4--                                                                          --
5--           A D A . C O N T A I N E R S . O R D E R E D _ M A P S          --
6--                                                                          --
7--                                 B o d y                                  --
8--                                                                          --
9--          Copyright (C) 2004-2013, 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
30with Ada.Unchecked_Deallocation;
31
32with Ada.Containers.Red_Black_Trees.Generic_Operations;
33pragma Elaborate_All (Ada.Containers.Red_Black_Trees.Generic_Operations);
34
35with Ada.Containers.Red_Black_Trees.Generic_Keys;
36pragma Elaborate_All (Ada.Containers.Red_Black_Trees.Generic_Keys);
37
38with System; use type System.Address;
39
40package body Ada.Containers.Ordered_Maps is
41
42   -----------------------------
43   -- Node Access Subprograms --
44   -----------------------------
45
46   --  These subprograms provide a functional interface to access fields
47   --  of a node, and a procedural interface for modifying these values.
48
49   function Color (Node : Node_Access) return Color_Type;
50   pragma Inline (Color);
51
52   function Left (Node : Node_Access) return Node_Access;
53   pragma Inline (Left);
54
55   function Parent (Node : Node_Access) return Node_Access;
56   pragma Inline (Parent);
57
58   function Right (Node : Node_Access) return Node_Access;
59   pragma Inline (Right);
60
61   procedure Set_Parent (Node : Node_Access; Parent : Node_Access);
62   pragma Inline (Set_Parent);
63
64   procedure Set_Left (Node : Node_Access; Left : Node_Access);
65   pragma Inline (Set_Left);
66
67   procedure Set_Right (Node : Node_Access; Right : Node_Access);
68   pragma Inline (Set_Right);
69
70   procedure Set_Color (Node : Node_Access; Color : Color_Type);
71   pragma Inline (Set_Color);
72
73   -----------------------
74   -- Local Subprograms --
75   -----------------------
76
77   function Copy_Node (Source : Node_Access) return Node_Access;
78   pragma Inline (Copy_Node);
79
80   procedure Free (X : in out Node_Access);
81
82   function Is_Equal_Node_Node (L, R : Node_Access) return Boolean;
83   pragma Inline (Is_Equal_Node_Node);
84
85   function Is_Greater_Key_Node
86     (Left  : Key_Type;
87      Right : Node_Access) return Boolean;
88   pragma Inline (Is_Greater_Key_Node);
89
90   function Is_Less_Key_Node
91     (Left  : Key_Type;
92      Right : Node_Access) return Boolean;
93   pragma Inline (Is_Less_Key_Node);
94
95   --------------------------
96   -- Local Instantiations --
97   --------------------------
98
99   package Tree_Operations is
100      new Red_Black_Trees.Generic_Operations (Tree_Types);
101
102   procedure Delete_Tree is
103      new Tree_Operations.Generic_Delete_Tree (Free);
104
105   function Copy_Tree is
106      new Tree_Operations.Generic_Copy_Tree (Copy_Node, Delete_Tree);
107
108   use Tree_Operations;
109
110   package Key_Ops is
111     new Red_Black_Trees.Generic_Keys
112       (Tree_Operations     => Tree_Operations,
113        Key_Type            => Key_Type,
114        Is_Less_Key_Node    => Is_Less_Key_Node,
115        Is_Greater_Key_Node => Is_Greater_Key_Node);
116
117   function Is_Equal is
118     new Tree_Operations.Generic_Equal (Is_Equal_Node_Node);
119
120   ---------
121   -- "<" --
122   ---------
123
124   function "<" (Left, Right : Cursor) return Boolean is
125   begin
126      if Left.Node = null then
127         raise Constraint_Error with "Left cursor of ""<"" equals No_Element";
128      end if;
129
130      if Right.Node = null then
131         raise Constraint_Error with "Right cursor of ""<"" equals No_Element";
132      end if;
133
134      pragma Assert (Vet (Left.Container.Tree, Left.Node),
135                     "Left cursor of ""<"" is bad");
136
137      pragma Assert (Vet (Right.Container.Tree, Right.Node),
138                     "Right cursor of ""<"" is bad");
139
140      return Left.Node.Key < Right.Node.Key;
141   end "<";
142
143   function "<" (Left : Cursor; Right : Key_Type) return Boolean is
144   begin
145      if Left.Node = null then
146         raise Constraint_Error with "Left cursor of ""<"" equals No_Element";
147      end if;
148
149      pragma Assert (Vet (Left.Container.Tree, Left.Node),
150                     "Left cursor of ""<"" is bad");
151
152      return Left.Node.Key < Right;
153   end "<";
154
155   function "<" (Left : Key_Type; Right : Cursor) return Boolean is
156   begin
157      if Right.Node = null then
158         raise Constraint_Error with "Right cursor of ""<"" equals No_Element";
159      end if;
160
161      pragma Assert (Vet (Right.Container.Tree, Right.Node),
162                     "Right cursor of ""<"" is bad");
163
164      return Left < Right.Node.Key;
165   end "<";
166
167   ---------
168   -- "=" --
169   ---------
170
171   function "=" (Left, Right : Map) return Boolean is
172   begin
173      return Is_Equal (Left.Tree, Right.Tree);
174   end "=";
175
176   ---------
177   -- ">" --
178   ---------
179
180   function ">" (Left, Right : Cursor) return Boolean is
181   begin
182      if Left.Node = null then
183         raise Constraint_Error with "Left cursor of "">"" equals No_Element";
184      end if;
185
186      if Right.Node = null then
187         raise Constraint_Error with "Right cursor of "">"" equals No_Element";
188      end if;
189
190      pragma Assert (Vet (Left.Container.Tree, Left.Node),
191                     "Left cursor of "">"" is bad");
192
193      pragma Assert (Vet (Right.Container.Tree, Right.Node),
194                     "Right cursor of "">"" is bad");
195
196      return Right.Node.Key < Left.Node.Key;
197   end ">";
198
199   function ">" (Left : Cursor; Right : Key_Type) return Boolean is
200   begin
201      if Left.Node = null then
202         raise Constraint_Error with "Left cursor of "">"" equals No_Element";
203      end if;
204
205      pragma Assert (Vet (Left.Container.Tree, Left.Node),
206                     "Left cursor of "">"" is bad");
207
208      return Right < Left.Node.Key;
209   end ">";
210
211   function ">" (Left : Key_Type; Right : Cursor) return Boolean is
212   begin
213      if Right.Node = null then
214         raise Constraint_Error with "Right cursor of "">"" equals No_Element";
215      end if;
216
217      pragma Assert (Vet (Right.Container.Tree, Right.Node),
218                     "Right cursor of "">"" is bad");
219
220      return Right.Node.Key < Left;
221   end ">";
222
223   ------------
224   -- Adjust --
225   ------------
226
227   procedure Adjust is
228      new Tree_Operations.Generic_Adjust (Copy_Tree);
229
230   procedure Adjust (Container : in out Map) is
231   begin
232      Adjust (Container.Tree);
233   end Adjust;
234
235   procedure Adjust (Control : in out Reference_Control_Type) is
236   begin
237      if Control.Container /= null then
238         declare
239            T : Tree_Type renames Control.Container.all.Tree;
240            B : Natural renames T.Busy;
241            L : Natural renames T.Lock;
242         begin
243            B := B + 1;
244            L := L + 1;
245         end;
246      end if;
247   end Adjust;
248
249   ------------
250   -- Assign --
251   ------------
252
253   procedure Assign (Target : in out Map; Source : Map) is
254      procedure Insert_Item (Node : Node_Access);
255      pragma Inline (Insert_Item);
256
257      procedure Insert_Items is
258         new Tree_Operations.Generic_Iteration (Insert_Item);
259
260      -----------------
261      -- Insert_Item --
262      -----------------
263
264      procedure Insert_Item (Node : Node_Access) is
265      begin
266         Target.Insert (Key => Node.Key, New_Item => Node.Element);
267      end Insert_Item;
268
269   --  Start of processing for Assign
270
271   begin
272      if Target'Address = Source'Address then
273         return;
274      end if;
275
276      Target.Clear;
277      Insert_Items (Source.Tree);
278   end Assign;
279
280   -------------
281   -- Ceiling --
282   -------------
283
284   function Ceiling (Container : Map; Key : Key_Type) return Cursor is
285      Node : constant Node_Access := Key_Ops.Ceiling (Container.Tree, Key);
286
287   begin
288      if Node = null then
289         return No_Element;
290      end if;
291
292      return Cursor'(Container'Unrestricted_Access, Node);
293   end Ceiling;
294
295   -----------
296   -- Clear --
297   -----------
298
299   procedure Clear is new Tree_Operations.Generic_Clear (Delete_Tree);
300
301   procedure Clear (Container : in out Map) is
302   begin
303      Clear (Container.Tree);
304   end Clear;
305
306   -----------
307   -- Color --
308   -----------
309
310   function Color (Node : Node_Access) return Color_Type is
311   begin
312      return Node.Color;
313   end Color;
314
315   ------------------------
316   -- Constant_Reference --
317   ------------------------
318
319   function Constant_Reference
320     (Container : aliased Map;
321      Position  : Cursor) return Constant_Reference_Type
322   is
323   begin
324      if Position.Container = null then
325         raise Constraint_Error with
326           "Position cursor has no element";
327      end if;
328
329      if Position.Container /= Container'Unrestricted_Access then
330         raise Program_Error with
331           "Position cursor designates wrong map";
332      end if;
333
334      pragma Assert (Vet (Container.Tree, Position.Node),
335                     "Position cursor in Constant_Reference is bad");
336
337      declare
338         T : Tree_Type renames Position.Container.all.Tree;
339         B : Natural renames T.Busy;
340         L : Natural renames T.Lock;
341      begin
342         return R : constant Constant_Reference_Type :=
343           (Element => Position.Node.Element'Access,
344            Control => (Controlled with Position.Container))
345         do
346            B := B + 1;
347            L := L + 1;
348         end return;
349      end;
350   end Constant_Reference;
351
352   function Constant_Reference
353     (Container : aliased Map;
354      Key       : Key_Type) return Constant_Reference_Type
355   is
356      Node : constant Node_Access := Key_Ops.Find (Container.Tree, Key);
357
358   begin
359      if Node = null then
360         raise Constraint_Error with "key not in map";
361      end if;
362
363      declare
364         T : Tree_Type renames Container'Unrestricted_Access.all.Tree;
365         B : Natural renames T.Busy;
366         L : Natural renames T.Lock;
367      begin
368         return R : constant Constant_Reference_Type :=
369           (Element => Node.Element'Access,
370            Control => (Controlled with Container'Unrestricted_Access))
371         do
372            B := B + 1;
373            L := L + 1;
374         end return;
375      end;
376   end Constant_Reference;
377
378   --------------
379   -- Contains --
380   --------------
381
382   function Contains (Container : Map; Key : Key_Type) return Boolean is
383   begin
384      return Find (Container, Key) /= No_Element;
385   end Contains;
386
387   ----------
388   -- Copy --
389   ----------
390
391   function Copy (Source : Map) return Map is
392   begin
393      return Target : Map do
394         Target.Assign (Source);
395      end return;
396   end Copy;
397
398   ---------------
399   -- Copy_Node --
400   ---------------
401
402   function Copy_Node (Source : Node_Access) return Node_Access is
403      Target : constant Node_Access :=
404        new Node_Type'(Color   => Source.Color,
405                       Key     => Source.Key,
406                       Element => Source.Element,
407                       Parent  => null,
408                       Left    => null,
409                       Right   => null);
410   begin
411      return Target;
412   end Copy_Node;
413
414   ------------
415   -- Delete --
416   ------------
417
418   procedure Delete (Container : in out Map; Position : in out Cursor) is
419      Tree : Tree_Type renames Container.Tree;
420
421   begin
422      if Position.Node = null then
423         raise Constraint_Error with
424           "Position cursor of Delete equals No_Element";
425      end if;
426
427      if Position.Container /= Container'Unrestricted_Access then
428         raise Program_Error with
429           "Position cursor of Delete designates wrong map";
430      end if;
431
432      pragma Assert (Vet (Tree, Position.Node),
433                     "Position cursor of Delete is bad");
434
435      Tree_Operations.Delete_Node_Sans_Free (Tree, Position.Node);
436      Free (Position.Node);
437
438      Position.Container := null;
439   end Delete;
440
441   procedure Delete (Container : in out Map; Key : Key_Type) is
442      X : Node_Access := Key_Ops.Find (Container.Tree, Key);
443
444   begin
445      if X = null then
446         raise Constraint_Error with "key not in map";
447      end if;
448
449      Tree_Operations.Delete_Node_Sans_Free (Container.Tree, X);
450      Free (X);
451   end Delete;
452
453   ------------------
454   -- Delete_First --
455   ------------------
456
457   procedure Delete_First (Container : in out Map) is
458      X : Node_Access := Container.Tree.First;
459
460   begin
461      if X /= null then
462         Tree_Operations.Delete_Node_Sans_Free (Container.Tree, X);
463         Free (X);
464      end if;
465   end Delete_First;
466
467   -----------------
468   -- Delete_Last --
469   -----------------
470
471   procedure Delete_Last (Container : in out Map) is
472      X : Node_Access := Container.Tree.Last;
473
474   begin
475      if X /= null then
476         Tree_Operations.Delete_Node_Sans_Free (Container.Tree, X);
477         Free (X);
478      end if;
479   end Delete_Last;
480
481   -------------
482   -- Element --
483   -------------
484
485   function Element (Position : Cursor) return Element_Type is
486   begin
487      if Position.Node = null then
488         raise Constraint_Error with
489           "Position cursor of function Element equals No_Element";
490      end if;
491
492      pragma Assert (Vet (Position.Container.Tree, Position.Node),
493                     "Position cursor of function Element is bad");
494
495      return Position.Node.Element;
496   end Element;
497
498   function Element (Container : Map; Key : Key_Type) return Element_Type is
499      Node : constant Node_Access := Key_Ops.Find (Container.Tree, Key);
500
501   begin
502      if Node = null then
503         raise Constraint_Error with "key not in map";
504      end if;
505
506      return Node.Element;
507   end Element;
508
509   ---------------------
510   -- Equivalent_Keys --
511   ---------------------
512
513   function Equivalent_Keys (Left, Right : Key_Type) return Boolean is
514   begin
515      if Left < Right
516        or else Right < Left
517      then
518         return False;
519      else
520         return True;
521      end if;
522   end Equivalent_Keys;
523
524   -------------
525   -- Exclude --
526   -------------
527
528   procedure Exclude (Container : in out Map; Key : Key_Type) is
529      X : Node_Access := Key_Ops.Find (Container.Tree, Key);
530
531   begin
532      if X /= null then
533         Tree_Operations.Delete_Node_Sans_Free (Container.Tree, X);
534         Free (X);
535      end if;
536   end Exclude;
537
538   --------------
539   -- Finalize --
540   --------------
541
542   procedure Finalize (Object : in out Iterator) is
543   begin
544      if Object.Container /= null then
545         declare
546            B : Natural renames Object.Container.all.Tree.Busy;
547         begin
548            B := B - 1;
549         end;
550      end if;
551   end Finalize;
552
553   procedure Finalize (Control : in out Reference_Control_Type) is
554   begin
555      if Control.Container /= null then
556         declare
557            T : Tree_Type renames Control.Container.all.Tree;
558            B : Natural renames T.Busy;
559            L : Natural renames T.Lock;
560         begin
561            B := B - 1;
562            L := L - 1;
563         end;
564
565         Control.Container := null;
566      end if;
567   end Finalize;
568
569   ----------
570   -- Find --
571   ----------
572
573   function Find (Container : Map; Key : Key_Type) return Cursor is
574      Node : constant Node_Access := Key_Ops.Find (Container.Tree, Key);
575   begin
576      return (if Node = null then No_Element
577                else Cursor'(Container'Unrestricted_Access, Node));
578   end Find;
579
580   -----------
581   -- First --
582   -----------
583
584   function First (Container : Map) return Cursor is
585      T : Tree_Type renames Container.Tree;
586   begin
587      if T.First = null then
588         return No_Element;
589      else
590         return Cursor'(Container'Unrestricted_Access, T.First);
591      end if;
592   end First;
593
594   function First (Object : Iterator) return Cursor is
595   begin
596      --  The value of the iterator object's Node component influences the
597      --  behavior of the First (and Last) selector function.
598
599      --  When the Node component is null, this means the iterator object was
600      --  constructed without a start expression, in which case the (forward)
601      --  iteration starts from the (logical) beginning of the entire sequence
602      --  of items (corresponding to Container.First, for a forward iterator).
603
604      --  Otherwise, this is iteration over a partial sequence of items. When
605      --  the Node component is non-null, the iterator object was constructed
606      --  with a start expression, that specifies the position from which the
607      --  (forward) partial iteration begins.
608
609      if Object.Node = null then
610         return Object.Container.First;
611      else
612         return Cursor'(Object.Container, Object.Node);
613      end if;
614   end First;
615
616   -------------------
617   -- First_Element --
618   -------------------
619
620   function First_Element (Container : Map) return Element_Type is
621      T : Tree_Type renames Container.Tree;
622   begin
623      if T.First = null then
624         raise Constraint_Error with "map is empty";
625      else
626         return T.First.Element;
627      end if;
628   end First_Element;
629
630   ---------------
631   -- First_Key --
632   ---------------
633
634   function First_Key (Container : Map) return Key_Type is
635      T : Tree_Type renames Container.Tree;
636   begin
637      if T.First = null then
638         raise Constraint_Error with "map is empty";
639      else
640         return T.First.Key;
641      end if;
642   end First_Key;
643
644   -----------
645   -- Floor --
646   -----------
647
648   function Floor (Container : Map; Key : Key_Type) return Cursor is
649      Node : constant Node_Access := Key_Ops.Floor (Container.Tree, Key);
650   begin
651      if Node = null then
652         return No_Element;
653      else
654         return Cursor'(Container'Unrestricted_Access, Node);
655      end if;
656   end Floor;
657
658   ----------
659   -- Free --
660   ----------
661
662   procedure Free (X : in out Node_Access) is
663      procedure Deallocate is
664         new Ada.Unchecked_Deallocation (Node_Type, Node_Access);
665
666   begin
667      if X = null then
668         return;
669      end if;
670
671      X.Parent := X;
672      X.Left := X;
673      X.Right := X;
674
675      Deallocate (X);
676   end Free;
677
678   -----------------
679   -- Has_Element --
680   -----------------
681
682   function Has_Element (Position : Cursor) return Boolean is
683   begin
684      return Position /= No_Element;
685   end Has_Element;
686
687   -------------
688   -- Include --
689   -------------
690
691   procedure Include
692     (Container : in out Map;
693      Key       : Key_Type;
694      New_Item  : Element_Type)
695   is
696      Position : Cursor;
697      Inserted : Boolean;
698
699   begin
700      Insert (Container, Key, New_Item, Position, Inserted);
701
702      if not Inserted then
703         if Container.Tree.Lock > 0 then
704            raise Program_Error with
705              "attempt to tamper with elements (map is locked)";
706         end if;
707
708         Position.Node.Key := Key;
709         Position.Node.Element := New_Item;
710      end if;
711   end Include;
712
713   ------------
714   -- Insert --
715   ------------
716
717   procedure Insert
718     (Container : in out Map;
719      Key       : Key_Type;
720      New_Item  : Element_Type;
721      Position  : out Cursor;
722      Inserted  : out Boolean)
723   is
724      function New_Node return Node_Access;
725      pragma Inline (New_Node);
726
727      procedure Insert_Post is
728        new Key_Ops.Generic_Insert_Post (New_Node);
729
730      procedure Insert_Sans_Hint is
731        new Key_Ops.Generic_Conditional_Insert (Insert_Post);
732
733      --------------
734      -- New_Node --
735      --------------
736
737      function New_Node return Node_Access is
738      begin
739         return new Node_Type'(Key     => Key,
740                               Element => New_Item,
741                               Color   => Red_Black_Trees.Red,
742                               Parent  => null,
743                               Left    => null,
744                               Right   => null);
745      end New_Node;
746
747   --  Start of processing for Insert
748
749   begin
750      Insert_Sans_Hint
751        (Container.Tree,
752         Key,
753         Position.Node,
754         Inserted);
755
756      Position.Container := Container'Unrestricted_Access;
757   end Insert;
758
759   procedure Insert
760     (Container : in out Map;
761      Key       : Key_Type;
762      New_Item  : Element_Type)
763   is
764      Position : Cursor;
765      pragma Unreferenced (Position);
766
767      Inserted : Boolean;
768
769   begin
770      Insert (Container, Key, New_Item, Position, Inserted);
771
772      if not Inserted then
773         raise Constraint_Error with "key already in map";
774      end if;
775   end Insert;
776
777   procedure Insert
778     (Container : in out Map;
779      Key       : Key_Type;
780      Position  : out Cursor;
781      Inserted  : out Boolean)
782   is
783      function New_Node return Node_Access;
784      pragma Inline (New_Node);
785
786      procedure Insert_Post is
787        new Key_Ops.Generic_Insert_Post (New_Node);
788
789      procedure Insert_Sans_Hint is
790        new Key_Ops.Generic_Conditional_Insert (Insert_Post);
791
792      --------------
793      -- New_Node --
794      --------------
795
796      function New_Node return Node_Access is
797      begin
798         return new Node_Type'(Key     => Key,
799                               Element => <>,
800                               Color   => Red_Black_Trees.Red,
801                               Parent  => null,
802                               Left    => null,
803                               Right   => null);
804      end New_Node;
805
806   --  Start of processing for Insert
807
808   begin
809      Insert_Sans_Hint
810        (Container.Tree,
811         Key,
812         Position.Node,
813         Inserted);
814
815      Position.Container := Container'Unrestricted_Access;
816   end Insert;
817
818   --------------
819   -- Is_Empty --
820   --------------
821
822   function Is_Empty (Container : Map) return Boolean is
823   begin
824      return Container.Tree.Length = 0;
825   end Is_Empty;
826
827   ------------------------
828   -- Is_Equal_Node_Node --
829   ------------------------
830
831   function Is_Equal_Node_Node
832     (L, R : Node_Access) return Boolean
833   is
834   begin
835      if L.Key < R.Key then
836         return False;
837      elsif R.Key < L.Key then
838         return False;
839      else
840         return L.Element = R.Element;
841      end if;
842   end Is_Equal_Node_Node;
843
844   -------------------------
845   -- Is_Greater_Key_Node --
846   -------------------------
847
848   function Is_Greater_Key_Node
849     (Left  : Key_Type;
850      Right : Node_Access) return Boolean
851   is
852   begin
853      --  Left > Right same as Right < Left
854
855      return Right.Key < Left;
856   end Is_Greater_Key_Node;
857
858   ----------------------
859   -- Is_Less_Key_Node --
860   ----------------------
861
862   function Is_Less_Key_Node
863     (Left  : Key_Type;
864      Right : Node_Access) return Boolean
865   is
866   begin
867      return Left < Right.Key;
868   end Is_Less_Key_Node;
869
870   -------------
871   -- Iterate --
872   -------------
873
874   procedure Iterate
875     (Container : Map;
876      Process   : not null access procedure (Position : Cursor))
877   is
878      procedure Process_Node (Node : Node_Access);
879      pragma Inline (Process_Node);
880
881      procedure Local_Iterate is
882         new Tree_Operations.Generic_Iteration (Process_Node);
883
884      ------------------
885      -- Process_Node --
886      ------------------
887
888      procedure Process_Node (Node : Node_Access) is
889      begin
890         Process (Cursor'(Container'Unrestricted_Access, Node));
891      end Process_Node;
892
893      B : Natural renames Container.Tree'Unrestricted_Access.all.Busy;
894
895   --  Start of processing for Iterate
896
897   begin
898      B := B + 1;
899
900      begin
901         Local_Iterate (Container.Tree);
902      exception
903         when others =>
904            B := B - 1;
905            raise;
906      end;
907
908      B := B - 1;
909   end Iterate;
910
911   function Iterate
912     (Container : Map) return Map_Iterator_Interfaces.Reversible_Iterator'Class
913   is
914      B  : Natural renames Container.Tree'Unrestricted_Access.all.Busy;
915
916   begin
917      --  The value of the Node component influences the behavior of the First
918      --  and Last selector functions of the iterator object. When the Node
919      --  component is null (as is the case here), this means the iterator
920      --  object was constructed without a start expression. This is a
921      --  complete iterator, meaning that the iteration starts from the
922      --  (logical) beginning of the sequence of items.
923
924      --  Note: For a forward iterator, Container.First is the beginning, and
925      --  for a reverse iterator, Container.Last is the beginning.
926
927      return It : constant Iterator :=
928        (Limited_Controlled with
929           Container => Container'Unrestricted_Access,
930           Node      => null)
931      do
932         B := B + 1;
933      end return;
934   end Iterate;
935
936   function Iterate (Container : Map; Start : Cursor)
937      return Map_Iterator_Interfaces.Reversible_Iterator'Class
938   is
939      B  : Natural renames Container.Tree'Unrestricted_Access.all.Busy;
940
941   begin
942      --  It was formerly the case that when Start = No_Element, the partial
943      --  iterator was defined to behave the same as for a complete iterator,
944      --  and iterate over the entire sequence of items. However, those
945      --  semantics were unintuitive and arguably error-prone (it is too easy
946      --  to accidentally create an endless loop), and so they were changed,
947      --  per the ARG meeting in Denver on 2011/11. However, there was no
948      --  consensus about what positive meaning this corner case should have,
949      --  and so it was decided to simply raise an exception. This does imply,
950      --  however, that it is not possible to use a partial iterator to specify
951      --  an empty sequence of items.
952
953      if Start = No_Element then
954         raise Constraint_Error with
955           "Start position for iterator equals No_Element";
956      end if;
957
958      if Start.Container /= Container'Unrestricted_Access then
959         raise Program_Error with
960           "Start cursor of Iterate designates wrong map";
961      end if;
962
963      pragma Assert (Vet (Container.Tree, Start.Node),
964                     "Start cursor of Iterate is bad");
965
966      --  The value of the Node component influences the behavior of the First
967      --  and Last selector functions of the iterator object. When the Node
968      --  component is non-null (as is the case here), it means that this
969      --  is a partial iteration, over a subset of the complete sequence of
970      --  items. The iterator object was constructed with a start expression,
971      --  indicating the position from which the iteration begins. Note that
972      --  the start position has the same value irrespective of whether this
973      --  is a forward or reverse iteration.
974
975      return It : constant Iterator :=
976        (Limited_Controlled with
977           Container => Container'Unrestricted_Access,
978           Node      => Start.Node)
979      do
980         B := B + 1;
981      end return;
982   end Iterate;
983
984   ---------
985   -- Key --
986   ---------
987
988   function Key (Position : Cursor) return Key_Type is
989   begin
990      if Position.Node = null then
991         raise Constraint_Error with
992           "Position cursor of function Key equals No_Element";
993      end if;
994
995      pragma Assert (Vet (Position.Container.Tree, Position.Node),
996                     "Position cursor of function Key is bad");
997
998      return Position.Node.Key;
999   end Key;
1000
1001   ----------
1002   -- Last --
1003   ----------
1004
1005   function Last (Container : Map) return Cursor is
1006      T : Tree_Type renames Container.Tree;
1007   begin
1008      if T.Last = null then
1009         return No_Element;
1010      else
1011         return Cursor'(Container'Unrestricted_Access, T.Last);
1012      end if;
1013   end Last;
1014
1015   function Last (Object : Iterator) return Cursor is
1016   begin
1017      --  The value of the iterator object's Node component influences the
1018      --  behavior of the Last (and First) selector function.
1019
1020      --  When the Node component is null, this means the iterator object was
1021      --  constructed without a start expression, in which case the (reverse)
1022      --  iteration starts from the (logical) beginning of the entire sequence
1023      --  (corresponding to Container.Last, for a reverse iterator).
1024
1025      --  Otherwise, this is iteration over a partial sequence of items. When
1026      --  the Node component is non-null, the iterator object was constructed
1027      --  with a start expression, that specifies the position from which the
1028      --  (reverse) partial iteration begins.
1029
1030      if Object.Node = null then
1031         return Object.Container.Last;
1032      else
1033         return Cursor'(Object.Container, Object.Node);
1034      end if;
1035   end Last;
1036
1037   ------------------
1038   -- Last_Element --
1039   ------------------
1040
1041   function Last_Element (Container : Map) return Element_Type is
1042      T : Tree_Type renames Container.Tree;
1043   begin
1044      if T.Last = null then
1045         raise Constraint_Error with "map is empty";
1046      else
1047         return T.Last.Element;
1048      end if;
1049   end Last_Element;
1050
1051   --------------
1052   -- Last_Key --
1053   --------------
1054
1055   function Last_Key (Container : Map) return Key_Type is
1056      T : Tree_Type renames Container.Tree;
1057   begin
1058      if T.Last = null then
1059         raise Constraint_Error with "map is empty";
1060      else
1061         return T.Last.Key;
1062      end if;
1063   end Last_Key;
1064
1065   ----------
1066   -- Left --
1067   ----------
1068
1069   function Left (Node : Node_Access) return Node_Access is
1070   begin
1071      return Node.Left;
1072   end Left;
1073
1074   ------------
1075   -- Length --
1076   ------------
1077
1078   function Length (Container : Map) return Count_Type is
1079   begin
1080      return Container.Tree.Length;
1081   end Length;
1082
1083   ----------
1084   -- Move --
1085   ----------
1086
1087   procedure Move is
1088      new Tree_Operations.Generic_Move (Clear);
1089
1090   procedure Move (Target : in out Map; Source : in out Map) is
1091   begin
1092      Move (Target => Target.Tree, Source => Source.Tree);
1093   end Move;
1094
1095   ----------
1096   -- Next --
1097   ----------
1098
1099   procedure Next (Position : in out Cursor) is
1100   begin
1101      Position := Next (Position);
1102   end Next;
1103
1104   function Next (Position : Cursor) return Cursor is
1105   begin
1106      if Position = No_Element then
1107         return No_Element;
1108      end if;
1109
1110      pragma Assert (Vet (Position.Container.Tree, Position.Node),
1111                     "Position cursor of Next is bad");
1112
1113      declare
1114         Node : constant Node_Access := Tree_Operations.Next (Position.Node);
1115
1116      begin
1117         if Node = null then
1118            return No_Element;
1119         end if;
1120
1121         return Cursor'(Position.Container, Node);
1122      end;
1123   end Next;
1124
1125   function Next
1126     (Object   : Iterator;
1127      Position : Cursor) return Cursor
1128   is
1129   begin
1130      if Position.Container = null then
1131         return No_Element;
1132      end if;
1133
1134      if Position.Container /= Object.Container then
1135         raise Program_Error with
1136           "Position cursor of Next designates wrong map";
1137      end if;
1138
1139      return Next (Position);
1140   end Next;
1141
1142   ------------
1143   -- Parent --
1144   ------------
1145
1146   function Parent (Node : Node_Access) return Node_Access is
1147   begin
1148      return Node.Parent;
1149   end Parent;
1150
1151   --------------
1152   -- Previous --
1153   --------------
1154
1155   procedure Previous (Position : in out Cursor) is
1156   begin
1157      Position := Previous (Position);
1158   end Previous;
1159
1160   function Previous (Position : Cursor) return Cursor is
1161   begin
1162      if Position = No_Element then
1163         return No_Element;
1164      end if;
1165
1166      pragma Assert (Vet (Position.Container.Tree, Position.Node),
1167                     "Position cursor of Previous is bad");
1168
1169      declare
1170         Node : constant Node_Access :=
1171           Tree_Operations.Previous (Position.Node);
1172
1173      begin
1174         if Node = null then
1175            return No_Element;
1176         end if;
1177
1178         return Cursor'(Position.Container, Node);
1179      end;
1180   end Previous;
1181
1182   function Previous
1183     (Object   : Iterator;
1184      Position : Cursor) return Cursor
1185   is
1186   begin
1187      if Position.Container = null then
1188         return No_Element;
1189      end if;
1190
1191      if Position.Container /= Object.Container then
1192         raise Program_Error with
1193           "Position cursor of Previous designates wrong map";
1194      end if;
1195
1196      return Previous (Position);
1197   end Previous;
1198
1199   -------------------
1200   -- Query_Element --
1201   -------------------
1202
1203   procedure Query_Element
1204     (Position : Cursor;
1205      Process  : not null access procedure (Key     : Key_Type;
1206                                            Element : Element_Type))
1207   is
1208   begin
1209      if Position.Node = null then
1210         raise Constraint_Error with
1211           "Position cursor of Query_Element equals No_Element";
1212      end if;
1213
1214      pragma Assert (Vet (Position.Container.Tree, Position.Node),
1215                     "Position cursor of Query_Element is bad");
1216
1217      declare
1218         T : Tree_Type renames Position.Container.Tree;
1219
1220         B : Natural renames T.Busy;
1221         L : Natural renames T.Lock;
1222
1223      begin
1224         B := B + 1;
1225         L := L + 1;
1226
1227         declare
1228            K : Key_Type renames Position.Node.Key;
1229            E : Element_Type renames Position.Node.Element;
1230
1231         begin
1232            Process (K, E);
1233         exception
1234            when others =>
1235               L := L - 1;
1236               B := B - 1;
1237               raise;
1238         end;
1239
1240         L := L - 1;
1241         B := B - 1;
1242      end;
1243   end Query_Element;
1244
1245   ----------
1246   -- Read --
1247   ----------
1248
1249   procedure Read
1250     (Stream    : not null access Root_Stream_Type'Class;
1251      Container : out Map)
1252   is
1253      function Read_Node
1254        (Stream : not null access Root_Stream_Type'Class) return Node_Access;
1255      pragma Inline (Read_Node);
1256
1257      procedure Read is
1258         new Tree_Operations.Generic_Read (Clear, Read_Node);
1259
1260      ---------------
1261      -- Read_Node --
1262      ---------------
1263
1264      function Read_Node
1265        (Stream : not null access Root_Stream_Type'Class) return Node_Access
1266      is
1267         Node : Node_Access := new Node_Type;
1268      begin
1269         Key_Type'Read (Stream, Node.Key);
1270         Element_Type'Read (Stream, Node.Element);
1271         return Node;
1272      exception
1273         when others =>
1274            Free (Node);
1275            raise;
1276      end Read_Node;
1277
1278   --  Start of processing for Read
1279
1280   begin
1281      Read (Stream, Container.Tree);
1282   end Read;
1283
1284   procedure Read
1285     (Stream : not null access Root_Stream_Type'Class;
1286      Item   : out Cursor)
1287   is
1288   begin
1289      raise Program_Error with "attempt to stream map cursor";
1290   end Read;
1291
1292   procedure Read
1293     (Stream : not null access Root_Stream_Type'Class;
1294      Item   : out Reference_Type)
1295   is
1296   begin
1297      raise Program_Error with "attempt to stream reference";
1298   end Read;
1299
1300   procedure Read
1301     (Stream : not null access Root_Stream_Type'Class;
1302      Item   : out Constant_Reference_Type)
1303   is
1304   begin
1305      raise Program_Error with "attempt to stream reference";
1306   end Read;
1307
1308   ---------------
1309   -- Reference --
1310   ---------------
1311
1312   function Reference
1313     (Container : aliased in out Map;
1314      Position  : Cursor) return Reference_Type
1315   is
1316   begin
1317      if Position.Container = null then
1318         raise Constraint_Error with
1319           "Position cursor has no element";
1320      end if;
1321
1322      if Position.Container /= Container'Unrestricted_Access then
1323         raise Program_Error with
1324           "Position cursor designates wrong map";
1325      end if;
1326
1327      pragma Assert (Vet (Container.Tree, Position.Node),
1328                     "Position cursor in function Reference is bad");
1329
1330      declare
1331         T : Tree_Type renames Position.Container.all.Tree;
1332         B : Natural renames T.Busy;
1333         L : Natural renames T.Lock;
1334      begin
1335         return R : constant Reference_Type :=
1336           (Element => Position.Node.Element'Access,
1337            Control => (Controlled with Position.Container))
1338         do
1339            B := B + 1;
1340            L := L + 1;
1341         end return;
1342      end;
1343   end Reference;
1344
1345   function Reference
1346     (Container : aliased in out Map;
1347      Key       : Key_Type) return Reference_Type
1348   is
1349      Node : constant Node_Access := Key_Ops.Find (Container.Tree, Key);
1350
1351   begin
1352      if Node = null then
1353         raise Constraint_Error with "key not in map";
1354      end if;
1355
1356      declare
1357         T : Tree_Type renames Container'Unrestricted_Access.all.Tree;
1358         B : Natural renames T.Busy;
1359         L : Natural renames T.Lock;
1360      begin
1361         return R : constant Reference_Type :=
1362           (Element => Node.Element'Access,
1363            Control => (Controlled with Container'Unrestricted_Access))
1364         do
1365            B := B + 1;
1366            L := L + 1;
1367         end return;
1368      end;
1369   end Reference;
1370
1371   -------------
1372   -- Replace --
1373   -------------
1374
1375   procedure Replace
1376     (Container : in out Map;
1377      Key       : Key_Type;
1378      New_Item  : Element_Type)
1379   is
1380      Node : constant Node_Access := Key_Ops.Find (Container.Tree, Key);
1381
1382   begin
1383      if Node = null then
1384         raise Constraint_Error with "key not in map";
1385      end if;
1386
1387      if Container.Tree.Lock > 0 then
1388         raise Program_Error with
1389           "attempt to tamper with elements (map is locked)";
1390      end if;
1391
1392      Node.Key := Key;
1393      Node.Element := New_Item;
1394   end Replace;
1395
1396   ---------------------
1397   -- Replace_Element --
1398   ---------------------
1399
1400   procedure Replace_Element
1401     (Container : in out Map;
1402      Position  : Cursor;
1403      New_Item  : Element_Type)
1404   is
1405   begin
1406      if Position.Node = null then
1407         raise Constraint_Error with
1408           "Position cursor of Replace_Element equals No_Element";
1409      end if;
1410
1411      if Position.Container /= Container'Unrestricted_Access then
1412         raise Program_Error with
1413           "Position cursor of Replace_Element designates wrong map";
1414      end if;
1415
1416      if Container.Tree.Lock > 0 then
1417         raise Program_Error with
1418           "attempt to tamper with elements (map is locked)";
1419      end if;
1420
1421      pragma Assert (Vet (Container.Tree, Position.Node),
1422                     "Position cursor of Replace_Element is bad");
1423
1424      Position.Node.Element := New_Item;
1425   end Replace_Element;
1426
1427   ---------------------
1428   -- Reverse_Iterate --
1429   ---------------------
1430
1431   procedure Reverse_Iterate
1432     (Container : Map;
1433      Process   : not null access procedure (Position : Cursor))
1434   is
1435      procedure Process_Node (Node : Node_Access);
1436      pragma Inline (Process_Node);
1437
1438      procedure Local_Reverse_Iterate is
1439         new Tree_Operations.Generic_Reverse_Iteration (Process_Node);
1440
1441      ------------------
1442      -- Process_Node --
1443      ------------------
1444
1445      procedure Process_Node (Node : Node_Access) is
1446      begin
1447         Process (Cursor'(Container'Unrestricted_Access, Node));
1448      end Process_Node;
1449
1450      B : Natural renames Container.Tree'Unrestricted_Access.all.Busy;
1451
1452   --  Start of processing for Reverse_Iterate
1453
1454   begin
1455      B := B + 1;
1456
1457      begin
1458         Local_Reverse_Iterate (Container.Tree);
1459      exception
1460         when others =>
1461            B := B - 1;
1462            raise;
1463      end;
1464
1465      B := B - 1;
1466   end Reverse_Iterate;
1467
1468   -----------
1469   -- Right --
1470   -----------
1471
1472   function Right (Node : Node_Access) return Node_Access is
1473   begin
1474      return Node.Right;
1475   end Right;
1476
1477   ---------------
1478   -- Set_Color --
1479   ---------------
1480
1481   procedure Set_Color
1482     (Node  : Node_Access;
1483      Color : Color_Type)
1484   is
1485   begin
1486      Node.Color := Color;
1487   end Set_Color;
1488
1489   --------------
1490   -- Set_Left --
1491   --------------
1492
1493   procedure Set_Left (Node : Node_Access; Left : Node_Access) is
1494   begin
1495      Node.Left := Left;
1496   end Set_Left;
1497
1498   ----------------
1499   -- Set_Parent --
1500   ----------------
1501
1502   procedure Set_Parent (Node : Node_Access; Parent : Node_Access) is
1503   begin
1504      Node.Parent := Parent;
1505   end Set_Parent;
1506
1507   ---------------
1508   -- Set_Right --
1509   ---------------
1510
1511   procedure Set_Right (Node : Node_Access; Right : Node_Access) is
1512   begin
1513      Node.Right := Right;
1514   end Set_Right;
1515
1516   --------------------
1517   -- Update_Element --
1518   --------------------
1519
1520   procedure Update_Element
1521     (Container : in out Map;
1522      Position  : Cursor;
1523      Process   : not null access procedure (Key     : Key_Type;
1524                                             Element : in out Element_Type))
1525   is
1526   begin
1527      if Position.Node = null then
1528         raise Constraint_Error with
1529           "Position cursor of Update_Element equals No_Element";
1530      end if;
1531
1532      if Position.Container /= Container'Unrestricted_Access then
1533         raise Program_Error with
1534           "Position cursor of Update_Element designates wrong map";
1535      end if;
1536
1537      pragma Assert (Vet (Container.Tree, Position.Node),
1538                     "Position cursor of Update_Element is bad");
1539
1540      declare
1541         T : Tree_Type renames Container.Tree;
1542
1543         B : Natural renames T.Busy;
1544         L : Natural renames T.Lock;
1545
1546      begin
1547         B := B + 1;
1548         L := L + 1;
1549
1550         declare
1551            K : Key_Type renames Position.Node.Key;
1552            E : Element_Type renames Position.Node.Element;
1553
1554         begin
1555            Process (K, E);
1556
1557         exception
1558            when others =>
1559               L := L - 1;
1560               B := B - 1;
1561               raise;
1562         end;
1563
1564         L := L - 1;
1565         B := B - 1;
1566      end;
1567   end Update_Element;
1568
1569   -----------
1570   -- Write --
1571   -----------
1572
1573   procedure Write
1574     (Stream    : not null access Root_Stream_Type'Class;
1575      Container : Map)
1576   is
1577      procedure Write_Node
1578        (Stream : not null access Root_Stream_Type'Class;
1579         Node   : Node_Access);
1580      pragma Inline (Write_Node);
1581
1582      procedure Write is
1583         new Tree_Operations.Generic_Write (Write_Node);
1584
1585      ----------------
1586      -- Write_Node --
1587      ----------------
1588
1589      procedure Write_Node
1590        (Stream : not null access Root_Stream_Type'Class;
1591         Node   : Node_Access)
1592      is
1593      begin
1594         Key_Type'Write (Stream, Node.Key);
1595         Element_Type'Write (Stream, Node.Element);
1596      end Write_Node;
1597
1598   --  Start of processing for Write
1599
1600   begin
1601      Write (Stream, Container.Tree);
1602   end Write;
1603
1604   procedure Write
1605     (Stream : not null access Root_Stream_Type'Class;
1606      Item   : Cursor)
1607   is
1608   begin
1609      raise Program_Error with "attempt to stream map cursor";
1610   end Write;
1611
1612   procedure Write
1613     (Stream : not null access Root_Stream_Type'Class;
1614      Item   : Reference_Type)
1615   is
1616   begin
1617      raise Program_Error with "attempt to stream reference";
1618   end Write;
1619
1620   procedure Write
1621     (Stream : not null access Root_Stream_Type'Class;
1622      Item   : Constant_Reference_Type)
1623   is
1624   begin
1625      raise Program_Error with "attempt to stream reference";
1626   end Write;
1627
1628end Ada.Containers.Ordered_Maps;
1629