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------------------------------------------------------------------------------
-- --
-- GNAT LIBRARY COMPONENTS --
-- --
-- ADA.CONTAINERS.RED_BLACK_TREES.GENERIC_OPERATIONS --
-- --
-- B o d y --
-- --
-- Copyright (C) 2004-2021, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. --
-- --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception, --
-- version 3.1, as published by the Free Software Foundation. --
-- --
-- You should have received a copy of the GNU General Public License and --
-- a copy of the GCC Runtime Library Exception along with this program; --
-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
-- <http://www.gnu.org/licenses/>. --
-- --
-- This unit was originally developed by Matthew J Heaney. --
------------------------------------------------------------------------------
-- The references below to "CLR" refer to the following book, from which
-- several of the algorithms here were adapted:
-- Introduction to Algorithms
-- by Thomas H. Cormen, Charles E. Leiserson, Ronald L. Rivest
-- Publisher: The MIT Press (June 18, 1990)
-- ISBN: 0262031418
with System; use type System.Address;
package body Ada.Containers.Red_Black_Trees.Generic_Operations is
pragma Warnings (Off, "variable ""Busy*"" is not referenced");
pragma Warnings (Off, "variable ""Lock*"" is not referenced");
-- See comment in Ada.Containers.Helpers
-----------------------
-- Local Subprograms --
-----------------------
procedure Delete_Fixup (Tree : in out Tree_Type; Node : Node_Access);
procedure Delete_Swap (Tree : in out Tree_Type; Z, Y : Node_Access);
procedure Left_Rotate (Tree : in out Tree_Type; X : Node_Access);
procedure Right_Rotate (Tree : in out Tree_Type; Y : Node_Access);
-- Why is all the following code commented out ???
-- ---------------------
-- -- Check_Invariant --
-- ---------------------
-- procedure Check_Invariant (Tree : Tree_Type) is
-- Root : constant Node_Access := Tree.Root;
--
-- function Check (Node : Node_Access) return Natural;
--
-- -----------
-- -- Check --
-- -----------
--
-- function Check (Node : Node_Access) return Natural is
-- begin
-- if Node = null then
-- return 0;
-- end if;
--
-- if Color (Node) = Red then
-- declare
-- L : constant Node_Access := Left (Node);
-- begin
-- pragma Assert (L = null or else Color (L) = Black);
-- null;
-- end;
--
-- declare
-- R : constant Node_Access := Right (Node);
-- begin
-- pragma Assert (R = null or else Color (R) = Black);
-- null;
-- end;
--
-- declare
-- NL : constant Natural := Check (Left (Node));
-- NR : constant Natural := Check (Right (Node));
-- begin
-- pragma Assert (NL = NR);
-- return NL;
-- end;
-- end if;
--
-- declare
-- NL : constant Natural := Check (Left (Node));
-- NR : constant Natural := Check (Right (Node));
-- begin
-- pragma Assert (NL = NR);
-- return NL + 1;
-- end;
-- end Check;
--
-- -- Start of processing for Check_Invariant
--
-- begin
-- if Root = null then
-- pragma Assert (Tree.First = null);
-- pragma Assert (Tree.Last = null);
-- pragma Assert (Tree.Length = 0);
-- null;
--
-- else
-- pragma Assert (Color (Root) = Black);
-- pragma Assert (Tree.Length > 0);
-- pragma Assert (Tree.Root /= null);
-- pragma Assert (Tree.First /= null);
-- pragma Assert (Tree.Last /= null);
-- pragma Assert (Parent (Tree.Root) = null);
-- pragma Assert ((Tree.Length > 1)
-- or else (Tree.First = Tree.Last
-- and Tree.First = Tree.Root));
-- pragma Assert (Left (Tree.First) = null);
-- pragma Assert (Right (Tree.Last) = null);
--
-- declare
-- L : constant Node_Access := Left (Root);
-- R : constant Node_Access := Right (Root);
-- NL : constant Natural := Check (L);
-- NR : constant Natural := Check (R);
-- begin
-- pragma Assert (NL = NR);
-- null;
-- end;
-- end if;
-- end Check_Invariant;
------------------
-- Delete_Fixup --
------------------
procedure Delete_Fixup (Tree : in out Tree_Type; Node : Node_Access) is
-- CLR p274
X : Node_Access := Node;
W : Node_Access;
begin
while X /= Tree.Root
and then Color (X) = Black
loop
if X = Left (Parent (X)) then
W := Right (Parent (X));
if Color (W) = Red then
Set_Color (W, Black);
Set_Color (Parent (X), Red);
Left_Rotate (Tree, Parent (X));
W := Right (Parent (X));
end if;
if (Left (W) = null or else Color (Left (W)) = Black)
and then
(Right (W) = null or else Color (Right (W)) = Black)
then
Set_Color (W, Red);
X := Parent (X);
else
if Right (W) = null
or else Color (Right (W)) = Black
then
-- As a condition for setting the color of the left child to
-- black, the left child access value must be non-null. A
-- truth table analysis shows that if we arrive here, that
-- condition holds, so there's no need for an explicit test.
-- The assertion is here to document what we know is true.
pragma Assert (Left (W) /= null);
Set_Color (Left (W), Black);
Set_Color (W, Red);
Right_Rotate (Tree, W);
W := Right (Parent (X));
end if;
Set_Color (W, Color (Parent (X)));
Set_Color (Parent (X), Black);
Set_Color (Right (W), Black);
Left_Rotate (Tree, Parent (X));
X := Tree.Root;
end if;
else
pragma Assert (X = Right (Parent (X)));
W := Left (Parent (X));
if Color (W) = Red then
Set_Color (W, Black);
Set_Color (Parent (X), Red);
Right_Rotate (Tree, Parent (X));
W := Left (Parent (X));
end if;
if (Left (W) = null or else Color (Left (W)) = Black)
and then
(Right (W) = null or else Color (Right (W)) = Black)
then
Set_Color (W, Red);
X := Parent (X);
else
if Left (W) = null or else Color (Left (W)) = Black then
-- As a condition for setting the color of the right child
-- to black, the right child access value must be non-null.
-- A truth table analysis shows that if we arrive here, that
-- condition holds, so there's no need for an explicit test.
-- The assertion is here to document what we know is true.
pragma Assert (Right (W) /= null);
Set_Color (Right (W), Black);
Set_Color (W, Red);
Left_Rotate (Tree, W);
W := Left (Parent (X));
end if;
Set_Color (W, Color (Parent (X)));
Set_Color (Parent (X), Black);
Set_Color (Left (W), Black);
Right_Rotate (Tree, Parent (X));
X := Tree.Root;
end if;
end if;
end loop;
Set_Color (X, Black);
end Delete_Fixup;
---------------------------
-- Delete_Node_Sans_Free --
---------------------------
procedure Delete_Node_Sans_Free
(Tree : in out Tree_Type;
Node : Node_Access)
is
-- CLR p273
X, Y : Node_Access;
Z : constant Node_Access := Node;
pragma Assert (Z /= null);
begin
TC_Check (Tree.TC);
-- Why are these all commented out ???
-- pragma Assert (Tree.Length > 0);
-- pragma Assert (Tree.Root /= null);
-- pragma Assert (Tree.First /= null);
-- pragma Assert (Tree.Last /= null);
-- pragma Assert (Parent (Tree.Root) = null);
-- pragma Assert ((Tree.Length > 1)
-- or else (Tree.First = Tree.Last
-- and then Tree.First = Tree.Root));
-- pragma Assert ((Left (Node) = null)
-- or else (Parent (Left (Node)) = Node));
-- pragma Assert ((Right (Node) = null)
-- or else (Parent (Right (Node)) = Node));
-- pragma Assert (((Parent (Node) = null) and then (Tree.Root = Node))
-- or else ((Parent (Node) /= null) and then
-- ((Left (Parent (Node)) = Node)
-- or else (Right (Parent (Node)) = Node))));
if Left (Z) = null then
if Right (Z) = null then
if Z = Tree.First then
Tree.First := Parent (Z);
end if;
if Z = Tree.Last then
Tree.Last := Parent (Z);
end if;
if Color (Z) = Black then
Delete_Fixup (Tree, Z);
end if;
pragma Assert (Left (Z) = null);
pragma Assert (Right (Z) = null);
if Z = Tree.Root then
pragma Assert (Tree.Length = 1);
pragma Assert (Parent (Z) = null);
Tree.Root := null;
elsif Z = Left (Parent (Z)) then
Set_Left (Parent (Z), null);
else
pragma Assert (Z = Right (Parent (Z)));
Set_Right (Parent (Z), null);
end if;
else
pragma Assert (Z /= Tree.Last);
X := Right (Z);
if Z = Tree.First then
Tree.First := Min (X);
end if;
if Z = Tree.Root then
Tree.Root := X;
elsif Z = Left (Parent (Z)) then
Set_Left (Parent (Z), X);
else
pragma Assert (Z = Right (Parent (Z)));
Set_Right (Parent (Z), X);
end if;
Set_Parent (X, Parent (Z));
if Color (Z) = Black then
Delete_Fixup (Tree, X);
end if;
end if;
elsif Right (Z) = null then
pragma Assert (Z /= Tree.First);
X := Left (Z);
if Z = Tree.Last then
Tree.Last := Max (X);
end if;
if Z = Tree.Root then
Tree.Root := X;
elsif Z = Left (Parent (Z)) then
Set_Left (Parent (Z), X);
else
pragma Assert (Z = Right (Parent (Z)));
Set_Right (Parent (Z), X);
end if;
Set_Parent (X, Parent (Z));
if Color (Z) = Black then
Delete_Fixup (Tree, X);
end if;
else
pragma Assert (Z /= Tree.First);
pragma Assert (Z /= Tree.Last);
Y := Next (Z);
pragma Assert (Left (Y) = null);
X := Right (Y);
if X = null then
if Y = Left (Parent (Y)) then
pragma Assert (Parent (Y) /= Z);
Delete_Swap (Tree, Z, Y);
Set_Left (Parent (Z), Z);
else
pragma Assert (Y = Right (Parent (Y)));
pragma Assert (Parent (Y) = Z);
Set_Parent (Y, Parent (Z));
if Z = Tree.Root then
Tree.Root := Y;
elsif Z = Left (Parent (Z)) then
Set_Left (Parent (Z), Y);
else
pragma Assert (Z = Right (Parent (Z)));
Set_Right (Parent (Z), Y);
end if;
Set_Left (Y, Left (Z));
Set_Parent (Left (Y), Y);
Set_Right (Y, Z);
Set_Parent (Z, Y);
Set_Left (Z, null);
Set_Right (Z, null);
declare
Y_Color : constant Color_Type := Color (Y);
begin
Set_Color (Y, Color (Z));
Set_Color (Z, Y_Color);
end;
end if;
if Color (Z) = Black then
Delete_Fixup (Tree, Z);
end if;
pragma Assert (Left (Z) = null);
pragma Assert (Right (Z) = null);
if Z = Right (Parent (Z)) then
Set_Right (Parent (Z), null);
else
pragma Assert (Z = Left (Parent (Z)));
Set_Left (Parent (Z), null);
end if;
else
if Y = Left (Parent (Y)) then
pragma Assert (Parent (Y) /= Z);
Delete_Swap (Tree, Z, Y);
Set_Left (Parent (Z), X);
Set_Parent (X, Parent (Z));
else
pragma Assert (Y = Right (Parent (Y)));
pragma Assert (Parent (Y) = Z);
Set_Parent (Y, Parent (Z));
if Z = Tree.Root then
Tree.Root := Y;
elsif Z = Left (Parent (Z)) then
Set_Left (Parent (Z), Y);
else
pragma Assert (Z = Right (Parent (Z)));
Set_Right (Parent (Z), Y);
end if;
Set_Left (Y, Left (Z));
Set_Parent (Left (Y), Y);
declare
Y_Color : constant Color_Type := Color (Y);
begin
Set_Color (Y, Color (Z));
Set_Color (Z, Y_Color);
end;
end if;
if Color (Z) = Black then
Delete_Fixup (Tree, X);
end if;
end if;
end if;
Tree.Length := Tree.Length - 1;
end Delete_Node_Sans_Free;
-----------------
-- Delete_Swap --
-----------------
procedure Delete_Swap
(Tree : in out Tree_Type;
Z, Y : Node_Access)
is
pragma Assert (Z /= Y);
pragma Assert (Parent (Y) /= Z);
Y_Parent : constant Node_Access := Parent (Y);
Y_Color : constant Color_Type := Color (Y);
begin
Set_Parent (Y, Parent (Z));
Set_Left (Y, Left (Z));
Set_Right (Y, Right (Z));
Set_Color (Y, Color (Z));
if Tree.Root = Z then
Tree.Root := Y;
elsif Right (Parent (Y)) = Z then
Set_Right (Parent (Y), Y);
else
pragma Assert (Left (Parent (Y)) = Z);
Set_Left (Parent (Y), Y);
end if;
if Right (Y) /= null then
Set_Parent (Right (Y), Y);
end if;
if Left (Y) /= null then
Set_Parent (Left (Y), Y);
end if;
Set_Parent (Z, Y_Parent);
Set_Color (Z, Y_Color);
Set_Left (Z, null);
Set_Right (Z, null);
end Delete_Swap;
--------------------
-- Generic_Adjust --
--------------------
procedure Generic_Adjust (Tree : in out Tree_Type) is
N : constant Count_Type := Tree.Length;
Root : constant Node_Access := Tree.Root;
begin
-- If the counts are nonzero, execution is technically erroneous, but
-- it seems friendly to allow things like concurrent "=" on shared
-- constants.
Zero_Counts (Tree.TC);
if N = 0 then
pragma Assert (Root = null);
return;
end if;
Tree.Root := null;
Tree.First := null;
Tree.Last := null;
Tree.Length := 0;
Tree.Root := Copy_Tree (Root);
Tree.First := Min (Tree.Root);
Tree.Last := Max (Tree.Root);
Tree.Length := N;
end Generic_Adjust;
-------------------
-- Generic_Clear --
-------------------
procedure Generic_Clear (Tree : in out Tree_Type) is
Root : Node_Access := Tree.Root;
begin
TC_Check (Tree.TC);
Tree := (First => null,
Last => null,
Root => null,
Length => 0,
TC => <>);
Delete_Tree (Root);
end Generic_Clear;
-----------------------
-- Generic_Copy_Tree --
-----------------------
function Generic_Copy_Tree (Source_Root : Node_Access) return Node_Access is
Target_Root : Node_Access := Copy_Node (Source_Root);
P, X : Node_Access;
begin
if Right (Source_Root) /= null then
Set_Right
(Node => Target_Root,
Right => Generic_Copy_Tree (Right (Source_Root)));
Set_Parent
(Node => Right (Target_Root),
Parent => Target_Root);
end if;
P := Target_Root;
X := Left (Source_Root);
while X /= null loop
declare
Y : constant Node_Access := Copy_Node (X);
begin
Set_Left (Node => P, Left => Y);
Set_Parent (Node => Y, Parent => P);
if Right (X) /= null then
Set_Right
(Node => Y,
Right => Generic_Copy_Tree (Right (X)));
Set_Parent
(Node => Right (Y),
Parent => Y);
end if;
P := Y;
X := Left (X);
end;
end loop;
return Target_Root;
exception
when others =>
Delete_Tree (Target_Root);
raise;
end Generic_Copy_Tree;
-------------------------
-- Generic_Delete_Tree --
-------------------------
procedure Generic_Delete_Tree (X : in out Node_Access) is
Y : Node_Access;
pragma Warnings (Off, Y);
begin
while X /= null loop
Y := Right (X);
Generic_Delete_Tree (Y);
Y := Left (X);
Free (X);
X := Y;
end loop;
end Generic_Delete_Tree;
-------------------
-- Generic_Equal --
-------------------
function Generic_Equal (Left, Right : Tree_Type) return Boolean is
begin
if Left.Length /= Right.Length then
return False;
end if;
-- If the containers are empty, return a result immediately, so as to
-- not manipulate the tamper bits unnecessarily.
if Left.Length = 0 then
return True;
end if;
declare
Lock_Left : With_Lock (Left.TC'Unrestricted_Access);
Lock_Right : With_Lock (Right.TC'Unrestricted_Access);
L_Node : Node_Access := Left.First;
R_Node : Node_Access := Right.First;
begin
while L_Node /= null loop
if not Is_Equal (L_Node, R_Node) then
return False;
end if;
L_Node := Next (L_Node);
R_Node := Next (R_Node);
end loop;
end;
return True;
end Generic_Equal;
-----------------------
-- Generic_Iteration --
-----------------------
procedure Generic_Iteration (Tree : Tree_Type) is
procedure Iterate (P : Node_Access);
-------------
-- Iterate --
-------------
procedure Iterate (P : Node_Access) is
X : Node_Access := P;
begin
while X /= null loop
Iterate (Left (X));
Process (X);
X := Right (X);
end loop;
end Iterate;
-- Start of processing for Generic_Iteration
begin
Iterate (Tree.Root);
end Generic_Iteration;
------------------
-- Generic_Move --
------------------
procedure Generic_Move (Target, Source : in out Tree_Type) is
begin
TC_Check (Source.TC);
if Target'Address = Source'Address then
return;
end if;
Clear (Target);
Target := Source;
Source := (First => null,
Last => null,
Root => null,
Length => 0,
TC => <>);
end Generic_Move;
------------------
-- Generic_Read --
------------------
procedure Generic_Read
(Stream : not null access Root_Stream_Type'Class;
Tree : in out Tree_Type)
is
N : Count_Type'Base;
Node, Last_Node : Node_Access;
begin
Clear (Tree);
Count_Type'Base'Read (Stream, N);
pragma Assert (N >= 0);
if N = 0 then
return;
end if;
Node := Read_Node (Stream);
pragma Assert (Node /= null);
pragma Assert (Color (Node) = Red);
Set_Color (Node, Black);
Tree.Root := Node;
Tree.First := Node;
Tree.Last := Node;
Tree.Length := 1;
for J in Count_Type range 2 .. N loop
Last_Node := Node;
pragma Assert (Last_Node = Tree.Last);
Node := Read_Node (Stream);
pragma Assert (Node /= null);
pragma Assert (Color (Node) = Red);
Set_Right (Node => Last_Node, Right => Node);
Tree.Last := Node;
Set_Parent (Node => Node, Parent => Last_Node);
Rebalance_For_Insert (Tree, Node);
Tree.Length := Tree.Length + 1;
end loop;
end Generic_Read;
-------------------------------
-- Generic_Reverse_Iteration --
-------------------------------
procedure Generic_Reverse_Iteration (Tree : Tree_Type)
is
procedure Iterate (P : Node_Access);
-------------
-- Iterate --
-------------
procedure Iterate (P : Node_Access) is
X : Node_Access := P;
begin
while X /= null loop
Iterate (Right (X));
Process (X);
X := Left (X);
end loop;
end Iterate;
-- Start of processing for Generic_Reverse_Iteration
begin
Iterate (Tree.Root);
end Generic_Reverse_Iteration;
-------------------
-- Generic_Write --
-------------------
procedure Generic_Write
(Stream : not null access Root_Stream_Type'Class;
Tree : Tree_Type)
is
procedure Process (Node : Node_Access);
pragma Inline (Process);
procedure Iterate is
new Generic_Iteration (Process);
-------------
-- Process --
-------------
procedure Process (Node : Node_Access) is
begin
Write_Node (Stream, Node);
end Process;
-- Start of processing for Generic_Write
begin
Count_Type'Base'Write (Stream, Tree.Length);
Iterate (Tree);
end Generic_Write;
-----------------
-- Left_Rotate --
-----------------
procedure Left_Rotate (Tree : in out Tree_Type; X : Node_Access) is
-- CLR p266
Y : constant Node_Access := Right (X);
pragma Assert (Y /= null);
begin
Set_Right (X, Left (Y));
if Left (Y) /= null then
Set_Parent (Left (Y), X);
end if;
Set_Parent (Y, Parent (X));
if X = Tree.Root then
Tree.Root := Y;
elsif X = Left (Parent (X)) then
Set_Left (Parent (X), Y);
else
pragma Assert (X = Right (Parent (X)));
Set_Right (Parent (X), Y);
end if;
Set_Left (Y, X);
Set_Parent (X, Y);
end Left_Rotate;
---------
-- Max --
---------
function Max (Node : Node_Access) return Node_Access is
-- CLR p248
X : Node_Access := Node;
Y : Node_Access;
begin
loop
Y := Right (X);
if Y = null then
return X;
end if;
X := Y;
end loop;
end Max;
---------
-- Min --
---------
function Min (Node : Node_Access) return Node_Access is
-- CLR p248
X : Node_Access := Node;
Y : Node_Access;
begin
loop
Y := Left (X);
if Y = null then
return X;
end if;
X := Y;
end loop;
end Min;
----------
-- Next --
----------
function Next (Node : Node_Access) return Node_Access is
begin
-- CLR p249
if Node = null then
return null;
end if;
if Right (Node) /= null then
return Min (Right (Node));
end if;
declare
X : Node_Access := Node;
Y : Node_Access := Parent (Node);
begin
while Y /= null
and then X = Right (Y)
loop
X := Y;
Y := Parent (Y);
end loop;
return Y;
end;
end Next;
--------------
-- Previous --
--------------
function Previous (Node : Node_Access) return Node_Access is
begin
if Node = null then
return null;
end if;
if Left (Node) /= null then
return Max (Left (Node));
end if;
declare
X : Node_Access := Node;
Y : Node_Access := Parent (Node);
begin
while Y /= null
and then X = Left (Y)
loop
X := Y;
Y := Parent (Y);
end loop;
return Y;
end;
end Previous;
--------------------------
-- Rebalance_For_Insert --
--------------------------
procedure Rebalance_For_Insert
(Tree : in out Tree_Type;
Node : Node_Access)
is
-- CLR p.268
X : Node_Access := Node;
pragma Assert (X /= null);
pragma Assert (Color (X) = Red);
Y : Node_Access;
begin
while X /= Tree.Root and then Color (Parent (X)) = Red loop
if Parent (X) = Left (Parent (Parent (X))) then
Y := Right (Parent (Parent (X)));
if Y /= null and then Color (Y) = Red then
Set_Color (Parent (X), Black);
Set_Color (Y, Black);
Set_Color (Parent (Parent (X)), Red);
X := Parent (Parent (X));
else
if X = Right (Parent (X)) then
X := Parent (X);
Left_Rotate (Tree, X);
end if;
Set_Color (Parent (X), Black);
Set_Color (Parent (Parent (X)), Red);
Right_Rotate (Tree, Parent (Parent (X)));
end if;
else
pragma Assert (Parent (X) = Right (Parent (Parent (X))));
Y := Left (Parent (Parent (X)));
if Y /= null and then Color (Y) = Red then
Set_Color (Parent (X), Black);
Set_Color (Y, Black);
Set_Color (Parent (Parent (X)), Red);
X := Parent (Parent (X));
else
if X = Left (Parent (X)) then
X := Parent (X);
Right_Rotate (Tree, X);
end if;
Set_Color (Parent (X), Black);
Set_Color (Parent (Parent (X)), Red);
Left_Rotate (Tree, Parent (Parent (X)));
end if;
end if;
end loop;
Set_Color (Tree.Root, Black);
end Rebalance_For_Insert;
------------------
-- Right_Rotate --
------------------
procedure Right_Rotate (Tree : in out Tree_Type; Y : Node_Access) is
X : constant Node_Access := Left (Y);
pragma Assert (X /= null);
begin
Set_Left (Y, Right (X));
if Right (X) /= null then
Set_Parent (Right (X), Y);
end if;
Set_Parent (X, Parent (Y));
if Y = Tree.Root then
Tree.Root := X;
elsif Y = Left (Parent (Y)) then
Set_Left (Parent (Y), X);
else
pragma Assert (Y = Right (Parent (Y)));
Set_Right (Parent (Y), X);
end if;
Set_Right (X, Y);
Set_Parent (Y, X);
end Right_Rotate;
---------
-- Vet --
---------
function Vet (Tree : Tree_Type; Node : Node_Access) return Boolean is
begin
if Node = null then
return True;
end if;
if Parent (Node) = Node
or else Left (Node) = Node
or else Right (Node) = Node
then
return False;
end if;
if Tree.Length = 0
or else Tree.Root = null
or else Tree.First = null
or else Tree.Last = null
then
return False;
end if;
if Parent (Tree.Root) /= null then
return False;
end if;
if Left (Tree.First) /= null then
return False;
end if;
if Right (Tree.Last) /= null then
return False;
end if;
if Tree.Length = 1 then
if Tree.First /= Tree.Last
or else Tree.First /= Tree.Root
then
return False;
end if;
if Node /= Tree.First then
return False;
end if;
if Parent (Node) /= null
or else Left (Node) /= null
or else Right (Node) /= null
then
return False;
end if;
return True;
end if;
if Tree.First = Tree.Last then
return False;
end if;
if Tree.Length = 2 then
if Tree.First /= Tree.Root
and then Tree.Last /= Tree.Root
then
return False;
end if;
if Tree.First /= Node
and then Tree.Last /= Node
then
return False;
end if;
end if;
if Left (Node) /= null
and then Parent (Left (Node)) /= Node
then
return False;
end if;
if Right (Node) /= null
and then Parent (Right (Node)) /= Node
then
return False;
end if;
if Parent (Node) = null then
if Tree.Root /= Node then
return False;
end if;
elsif Left (Parent (Node)) /= Node
and then Right (Parent (Node)) /= Node
then
return False;
end if;
return True;
end Vet;
end Ada.Containers.Red_Black_Trees.Generic_Operations;