------------------------------------------------------------------------------ | |

-- -- | |

-- GNAT LIBRARY COMPONENTS -- | |

-- -- | |

-- ADA.CONTAINERS.RED_BLACK_TREES.GENERIC_BOUNDED_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 in this file 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_Bounded_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'Class; Node : Count_Type); | |

procedure Delete_Swap (Tree : in out Tree_Type'Class; Z, Y : Count_Type); | |

procedure Left_Rotate (Tree : in out Tree_Type'Class; X : Count_Type); | |

procedure Right_Rotate (Tree : in out Tree_Type'Class; Y : Count_Type); | |

---------------- | |

-- Clear_Tree -- | |

---------------- | |

procedure Clear_Tree (Tree : in out Tree_Type'Class) is | |

begin | |

TC_Check (Tree.TC); | |

Tree.First := 0; | |

Tree.Last := 0; | |

Tree.Root := 0; | |

Tree.Length := 0; | |

Tree.Free := -1; | |

end Clear_Tree; | |

------------------ | |

-- Delete_Fixup -- | |

------------------ | |

procedure Delete_Fixup | |

(Tree : in out Tree_Type'Class; | |

Node : Count_Type) | |

is | |

-- CLR p. 274 | |

X : Count_Type; | |

W : Count_Type; | |

N : Nodes_Type renames Tree.Nodes; | |

begin | |

X := Node; | |

while X /= Tree.Root and then Color (N (X)) = Black loop | |

if X = Left (N (Parent (N (X)))) then | |

W := Right (N (Parent (N (X)))); | |

if Color (N (W)) = Red then | |

Set_Color (N (W), Black); | |

Set_Color (N (Parent (N (X))), Red); | |

Left_Rotate (Tree, Parent (N (X))); | |

W := Right (N (Parent (N (X)))); | |

end if; | |

if (Left (N (W)) = 0 or else Color (N (Left (N (W)))) = Black) | |

and then | |

(Right (N (W)) = 0 or else Color (N (Right (N (W)))) = Black) | |

then | |

Set_Color (N (W), Red); | |

X := Parent (N (X)); | |

else | |

if Right (N (W)) = 0 | |

or else Color (N (Right (N (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 (N (W)) /= 0); | |

Set_Color (N (Left (N (W))), Black); | |

Set_Color (N (W), Red); | |

Right_Rotate (Tree, W); | |

W := Right (N (Parent (N (X)))); | |

end if; | |

Set_Color (N (W), Color (N (Parent (N (X))))); | |

Set_Color (N (Parent (N (X))), Black); | |

Set_Color (N (Right (N (W))), Black); | |

Left_Rotate (Tree, Parent (N (X))); | |

X := Tree.Root; | |

end if; | |

else | |

pragma Assert (X = Right (N (Parent (N (X))))); | |

W := Left (N (Parent (N (X)))); | |

if Color (N (W)) = Red then | |

Set_Color (N (W), Black); | |

Set_Color (N (Parent (N (X))), Red); | |

Right_Rotate (Tree, Parent (N (X))); | |

W := Left (N (Parent (N (X)))); | |

end if; | |

if (Left (N (W)) = 0 or else Color (N (Left (N (W)))) = Black) | |

and then | |

(Right (N (W)) = 0 or else Color (N (Right (N (W)))) = Black) | |

then | |

Set_Color (N (W), Red); | |

X := Parent (N (X)); | |

else | |

if Left (N (W)) = 0 | |

or else Color (N (Left (N (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 (N (W)) /= 0); | |

Set_Color (N (Right (N (W))), Black); | |

Set_Color (N (W), Red); | |

Left_Rotate (Tree, W); | |

W := Left (N (Parent (N (X)))); | |

end if; | |

Set_Color (N (W), Color (N (Parent (N (X))))); | |

Set_Color (N (Parent (N (X))), Black); | |

Set_Color (N (Left (N (W))), Black); | |

Right_Rotate (Tree, Parent (N (X))); | |

X := Tree.Root; | |

end if; | |

end if; | |

end loop; | |

Set_Color (N (X), Black); | |

end Delete_Fixup; | |

--------------------------- | |

-- Delete_Node_Sans_Free -- | |

--------------------------- | |

procedure Delete_Node_Sans_Free | |

(Tree : in out Tree_Type'Class; | |

Node : Count_Type) | |

is | |

-- CLR p. 273 | |

X, Y : Count_Type; | |

Z : constant Count_Type := Node; | |

N : Nodes_Type renames Tree.Nodes; | |

begin | |

TC_Check (Tree.TC); | |

-- If node is not present, return (exception will be raised in caller) | |

if Z = 0 then | |

return; | |

end if; | |

pragma Assert (Tree.Length > 0); | |

pragma Assert (Tree.Root /= 0); | |

pragma Assert (Tree.First /= 0); | |

pragma Assert (Tree.Last /= 0); | |

pragma Assert (Parent (N (Tree.Root)) = 0); | |

pragma Assert ((Tree.Length > 1) | |

or else (Tree.First = Tree.Last | |

and then Tree.First = Tree.Root)); | |

pragma Assert ((Left (N (Node)) = 0) | |

or else (Parent (N (Left (N (Node)))) = Node)); | |

pragma Assert ((Right (N (Node)) = 0) | |

or else (Parent (N (Right (N (Node)))) = Node)); | |

pragma Assert (((Parent (N (Node)) = 0) and then (Tree.Root = Node)) | |

or else ((Parent (N (Node)) /= 0) and then | |

((Left (N (Parent (N (Node)))) = Node) | |

or else | |

(Right (N (Parent (N (Node)))) = Node)))); | |

if Left (N (Z)) = 0 then | |

if Right (N (Z)) = 0 then | |

if Z = Tree.First then | |

Tree.First := Parent (N (Z)); | |

end if; | |

if Z = Tree.Last then | |

Tree.Last := Parent (N (Z)); | |

end if; | |

if Color (N (Z)) = Black then | |

Delete_Fixup (Tree, Z); | |

end if; | |

pragma Assert (Left (N (Z)) = 0); | |

pragma Assert (Right (N (Z)) = 0); | |

if Z = Tree.Root then | |

pragma Assert (Tree.Length = 1); | |

pragma Assert (Parent (N (Z)) = 0); | |

Tree.Root := 0; | |

elsif Z = Left (N (Parent (N (Z)))) then | |

Set_Left (N (Parent (N (Z))), 0); | |

else | |

pragma Assert (Z = Right (N (Parent (N (Z))))); | |

Set_Right (N (Parent (N (Z))), 0); | |

end if; | |

else | |

pragma Assert (Z /= Tree.Last); | |

X := Right (N (Z)); | |

if Z = Tree.First then | |

Tree.First := Min (Tree, X); | |

end if; | |

if Z = Tree.Root then | |

Tree.Root := X; | |

elsif Z = Left (N (Parent (N (Z)))) then | |

Set_Left (N (Parent (N (Z))), X); | |

else | |

pragma Assert (Z = Right (N (Parent (N (Z))))); | |

Set_Right (N (Parent (N (Z))), X); | |

end if; | |

Set_Parent (N (X), Parent (N (Z))); | |

if Color (N (Z)) = Black then | |

Delete_Fixup (Tree, X); | |

end if; | |

end if; | |

elsif Right (N (Z)) = 0 then | |

pragma Assert (Z /= Tree.First); | |

X := Left (N (Z)); | |

if Z = Tree.Last then | |

Tree.Last := Max (Tree, X); | |

end if; | |

if Z = Tree.Root then | |

Tree.Root := X; | |

elsif Z = Left (N (Parent (N (Z)))) then | |

Set_Left (N (Parent (N (Z))), X); | |

else | |

pragma Assert (Z = Right (N (Parent (N (Z))))); | |

Set_Right (N (Parent (N (Z))), X); | |

end if; | |

Set_Parent (N (X), Parent (N (Z))); | |

if Color (N (Z)) = Black then | |

Delete_Fixup (Tree, X); | |

end if; | |

else | |

pragma Assert (Z /= Tree.First); | |

pragma Assert (Z /= Tree.Last); | |

Y := Next (Tree, Z); | |

pragma Assert (Left (N (Y)) = 0); | |

X := Right (N (Y)); | |

if X = 0 then | |

if Y = Left (N (Parent (N (Y)))) then | |

pragma Assert (Parent (N (Y)) /= Z); | |

Delete_Swap (Tree, Z, Y); | |

Set_Left (N (Parent (N (Z))), Z); | |

else | |

pragma Assert (Y = Right (N (Parent (N (Y))))); | |

pragma Assert (Parent (N (Y)) = Z); | |

Set_Parent (N (Y), Parent (N (Z))); | |

if Z = Tree.Root then | |

Tree.Root := Y; | |

elsif Z = Left (N (Parent (N (Z)))) then | |

Set_Left (N (Parent (N (Z))), Y); | |

else | |

pragma Assert (Z = Right (N (Parent (N (Z))))); | |

Set_Right (N (Parent (N (Z))), Y); | |

end if; | |

Set_Left (N (Y), Left (N (Z))); | |

Set_Parent (N (Left (N (Y))), Y); | |

Set_Right (N (Y), Z); | |

Set_Parent (N (Z), Y); | |

Set_Left (N (Z), 0); | |

Set_Right (N (Z), 0); | |

declare | |

Y_Color : constant Color_Type := Color (N (Y)); | |

begin | |

Set_Color (N (Y), Color (N (Z))); | |

Set_Color (N (Z), Y_Color); | |

end; | |

end if; | |

if Color (N (Z)) = Black then | |

Delete_Fixup (Tree, Z); | |

end if; | |

pragma Assert (Left (N (Z)) = 0); | |

pragma Assert (Right (N (Z)) = 0); | |

if Z = Right (N (Parent (N (Z)))) then | |

Set_Right (N (Parent (N (Z))), 0); | |

else | |

pragma Assert (Z = Left (N (Parent (N (Z))))); | |

Set_Left (N (Parent (N (Z))), 0); | |

end if; | |

else | |

if Y = Left (N (Parent (N (Y)))) then | |

pragma Assert (Parent (N (Y)) /= Z); | |

Delete_Swap (Tree, Z, Y); | |

Set_Left (N (Parent (N (Z))), X); | |

Set_Parent (N (X), Parent (N (Z))); | |

else | |

pragma Assert (Y = Right (N (Parent (N (Y))))); | |

pragma Assert (Parent (N (Y)) = Z); | |

Set_Parent (N (Y), Parent (N (Z))); | |

if Z = Tree.Root then | |

Tree.Root := Y; | |

elsif Z = Left (N (Parent (N (Z)))) then | |

Set_Left (N (Parent (N (Z))), Y); | |

else | |

pragma Assert (Z = Right (N (Parent (N (Z))))); | |

Set_Right (N (Parent (N (Z))), Y); | |

end if; | |

Set_Left (N (Y), Left (N (Z))); | |

Set_Parent (N (Left (N (Y))), Y); | |

declare | |

Y_Color : constant Color_Type := Color (N (Y)); | |

begin | |

Set_Color (N (Y), Color (N (Z))); | |

Set_Color (N (Z), Y_Color); | |

end; | |

end if; | |

if Color (N (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'Class; | |

Z, Y : Count_Type) | |

is | |

N : Nodes_Type renames Tree.Nodes; | |

pragma Assert (Z /= Y); | |

pragma Assert (Parent (N (Y)) /= Z); | |

Y_Parent : constant Count_Type := Parent (N (Y)); | |

Y_Color : constant Color_Type := Color (N (Y)); | |

begin | |

Set_Parent (N (Y), Parent (N (Z))); | |

Set_Left (N (Y), Left (N (Z))); | |

Set_Right (N (Y), Right (N (Z))); | |

Set_Color (N (Y), Color (N (Z))); | |

if Tree.Root = Z then | |

Tree.Root := Y; | |

elsif Right (N (Parent (N (Y)))) = Z then | |

Set_Right (N (Parent (N (Y))), Y); | |

else | |

pragma Assert (Left (N (Parent (N (Y)))) = Z); | |

Set_Left (N (Parent (N (Y))), Y); | |

end if; | |

if Right (N (Y)) /= 0 then | |

Set_Parent (N (Right (N (Y))), Y); | |

end if; | |

if Left (N (Y)) /= 0 then | |

Set_Parent (N (Left (N (Y))), Y); | |

end if; | |

Set_Parent (N (Z), Y_Parent); | |

Set_Color (N (Z), Y_Color); | |

Set_Left (N (Z), 0); | |

Set_Right (N (Z), 0); | |

end Delete_Swap; | |

---------- | |

-- Free -- | |

---------- | |

procedure Free (Tree : in out Tree_Type'Class; X : Count_Type) is | |

pragma Assert (X > 0); | |

pragma Assert (X <= Tree.Capacity); | |

N : Nodes_Type renames Tree.Nodes; | |

-- pragma Assert (N (X).Prev >= 0); -- node is active | |

-- Find a way to mark a node as active vs. inactive; we could | |

-- use a special value in Color_Type for this. ??? | |

begin | |

-- The set container actually contains two data structures: a list for | |

-- the "active" nodes that contain elements that have been inserted | |

-- onto the tree, and another for the "inactive" nodes of the free | |

-- store. | |

-- | |

-- We desire that merely declaring an object should have only minimal | |

-- cost; specially, we want to avoid having to initialize the free | |

-- store (to fill in the links), especially if the capacity is large. | |

-- | |

-- The head of the free list is indicated by Container.Free. If its | |

-- value is non-negative, then the free store has been initialized | |

-- in the "normal" way: Container.Free points to the head of the list | |

-- of free (inactive) nodes, and the value 0 means the free list is | |

-- empty. Each node on the free list has been initialized to point | |

-- to the next free node (via its Parent component), and the value 0 | |

-- means that this is the last free node. | |

-- | |

-- If Container.Free is negative, then the links on the free store | |

-- have not been initialized. In this case the link values are | |

-- implied: the free store comprises the components of the node array | |

-- started with the absolute value of Container.Free, and continuing | |

-- until the end of the array (Nodes'Last). | |

-- | |

-- ??? | |

-- It might be possible to perform an optimization here. Suppose that | |

-- the free store can be represented as having two parts: one | |

-- comprising the non-contiguous inactive nodes linked together | |

-- in the normal way, and the other comprising the contiguous | |

-- inactive nodes (that are not linked together, at the end of the | |

-- nodes array). This would allow us to never have to initialize | |

-- the free store, except in a lazy way as nodes become inactive. | |

-- When an element is deleted from the list container, its node | |

-- becomes inactive, and so we set its Prev component to a negative | |

-- value, to indicate that it is now inactive. This provides a useful | |

-- way to detect a dangling cursor reference. | |

-- The comment above is incorrect; we need some other way to | |

-- indicate a node is inactive, for example by using a special | |

-- Color_Type value. ??? | |

-- N (X).Prev := -1; -- Node is deallocated (not on active list) | |

if Tree.Free >= 0 then | |

-- The free store has previously been initialized. All we need to | |

-- do here is link the newly-free'd node onto the free list. | |

Set_Parent (N (X), Tree.Free); | |

Tree.Free := X; | |

elsif X + 1 = abs Tree.Free then | |

-- The free store has not been initialized, and the node becoming | |

-- inactive immediately precedes the start of the free store. All | |

-- we need to do is move the start of the free store back by one. | |

Tree.Free := Tree.Free + 1; | |

else | |

-- The free store has not been initialized, and the node becoming | |

-- inactive does not immediately precede the free store. Here we | |

-- first initialize the free store (meaning the links are given | |

-- values in the traditional way), and then link the newly-free'd | |

-- node onto the head of the free store. | |

-- ??? | |

-- See the comments above for an optimization opportunity. If the | |

-- next link for a node on the free store is negative, then this | |

-- means the remaining nodes on the free store are physically | |

-- contiguous, starting as the absolute value of that index value. | |

Tree.Free := abs Tree.Free; | |

if Tree.Free > Tree.Capacity then | |

Tree.Free := 0; | |

else | |

for I in Tree.Free .. Tree.Capacity - 1 loop | |

Set_Parent (N (I), I + 1); | |

end loop; | |

Set_Parent (N (Tree.Capacity), 0); | |

end if; | |

Set_Parent (N (X), Tree.Free); | |

Tree.Free := X; | |

end if; | |

end Free; | |

----------------------- | |

-- Generic_Allocate -- | |

----------------------- | |

procedure Generic_Allocate | |

(Tree : in out Tree_Type'Class; | |

Node : out Count_Type) | |

is | |

N : Nodes_Type renames Tree.Nodes; | |

begin | |

if Tree.Free >= 0 then | |

Node := Tree.Free; | |

-- We always perform the assignment first, before we | |

-- change container state, in order to defend against | |

-- exceptions duration assignment. | |

Set_Element (N (Node)); | |

Tree.Free := Parent (N (Node)); | |

else | |

-- A negative free store value means that the links of the nodes | |

-- in the free store have not been initialized. In this case, the | |

-- nodes are physically contiguous in the array, starting at the | |

-- index that is the absolute value of the Container.Free, and | |

-- continuing until the end of the array (Nodes'Last). | |

Node := abs Tree.Free; | |

-- As above, we perform this assignment first, before modifying | |

-- any container state. | |

Set_Element (N (Node)); | |

Tree.Free := Tree.Free - 1; | |

end if; | |

-- When a node is allocated from the free store, its pointer components | |

-- (the links to other nodes in the tree) must also be initialized (to | |

-- 0, the equivalent of null). This simplifies the post-allocation | |

-- handling of nodes inserted into terminal positions. | |

Set_Parent (N (Node), Parent => 0); | |

Set_Left (N (Node), Left => 0); | |

Set_Right (N (Node), Right => 0); | |

end Generic_Allocate; | |

------------------- | |

-- Generic_Equal -- | |

------------------- | |

function Generic_Equal (Left, Right : Tree_Type'Class) return Boolean is | |

-- Per AI05-0022, the container implementation is required to detect | |

-- element tampering by a generic actual subprogram. | |

Lock_Left : With_Lock (Left.TC'Unrestricted_Access); | |

Lock_Right : With_Lock (Right.TC'Unrestricted_Access); | |

L_Node : Count_Type; | |

R_Node : Count_Type; | |

begin | |

if Left'Address = Right'Address then | |

return True; | |

end if; | |

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; | |

L_Node := Left.First; | |

R_Node := Right.First; | |

while L_Node /= 0 loop | |

if not Is_Equal (Left.Nodes (L_Node), Right.Nodes (R_Node)) then | |

return False; | |

end if; | |

L_Node := Next (Left, L_Node); | |

R_Node := Next (Right, R_Node); | |

end loop; | |

return True; | |

end Generic_Equal; | |

----------------------- | |

-- Generic_Iteration -- | |

----------------------- | |

procedure Generic_Iteration (Tree : Tree_Type'Class) is | |

procedure Iterate (P : Count_Type); | |

------------- | |

-- Iterate -- | |

------------- | |

procedure Iterate (P : Count_Type) is | |

X : Count_Type := P; | |

begin | |

while X /= 0 loop | |

Iterate (Left (Tree.Nodes (X))); | |

Process (X); | |

X := Right (Tree.Nodes (X)); | |

end loop; | |

end Iterate; | |

-- Start of processing for Generic_Iteration | |

begin | |

Iterate (Tree.Root); | |

end Generic_Iteration; | |

------------------ | |

-- Generic_Read -- | |

------------------ | |

procedure Generic_Read | |

(Stream : not null access Root_Stream_Type'Class; | |

Tree : in out Tree_Type'Class) | |

is | |

Len : Count_Type'Base; | |

Node, Last_Node : Count_Type; | |

N : Nodes_Type renames Tree.Nodes; | |

begin | |

Clear_Tree (Tree); | |

Count_Type'Base'Read (Stream, Len); | |

if Checks and then Len < 0 then | |

raise Program_Error with "bad container length (corrupt stream)"; | |

end if; | |

if Len = 0 then | |

return; | |

end if; | |

if Checks and then Len > Tree.Capacity then | |

raise Constraint_Error with "length exceeds capacity"; | |

end if; | |

-- Use Unconditional_Insert_With_Hint here instead ??? | |

Allocate (Tree, Node); | |

pragma Assert (Node /= 0); | |

Set_Color (N (Node), Black); | |

Tree.Root := Node; | |

Tree.First := Node; | |

Tree.Last := Node; | |

Tree.Length := 1; | |

for J in Count_Type range 2 .. Len loop | |

Last_Node := Node; | |

pragma Assert (Last_Node = Tree.Last); | |

Allocate (Tree, Node); | |

pragma Assert (Node /= 0); | |

Set_Color (N (Node), Red); | |

Set_Right (N (Last_Node), Right => Node); | |

Tree.Last := Node; | |

Set_Parent (N (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'Class) is | |

procedure Iterate (P : Count_Type); | |

------------- | |

-- Iterate -- | |

------------- | |

procedure Iterate (P : Count_Type) is | |

X : Count_Type := P; | |

begin | |

while X /= 0 loop | |

Iterate (Right (Tree.Nodes (X))); | |

Process (X); | |

X := Left (Tree.Nodes (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'Class) | |

is | |

procedure Process (Node : Count_Type); | |

pragma Inline (Process); | |

procedure Iterate is new Generic_Iteration (Process); | |

------------- | |

-- Process -- | |

------------- | |

procedure Process (Node : Count_Type) is | |

begin | |

Write_Node (Stream, Tree.Nodes (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'Class; X : Count_Type) is | |

-- CLR p. 266 | |

N : Nodes_Type renames Tree.Nodes; | |

Y : constant Count_Type := Right (N (X)); | |

pragma Assert (Y /= 0); | |

begin | |

Set_Right (N (X), Left (N (Y))); | |

if Left (N (Y)) /= 0 then | |

Set_Parent (N (Left (N (Y))), X); | |

end if; | |

Set_Parent (N (Y), Parent (N (X))); | |

if X = Tree.Root then | |

Tree.Root := Y; | |

elsif X = Left (N (Parent (N (X)))) then | |

Set_Left (N (Parent (N (X))), Y); | |

else | |

pragma Assert (X = Right (N (Parent (N (X))))); | |

Set_Right (N (Parent (N (X))), Y); | |

end if; | |

Set_Left (N (Y), X); | |

Set_Parent (N (X), Y); | |

end Left_Rotate; | |

--------- | |

-- Max -- | |

--------- | |

function Max | |

(Tree : Tree_Type'Class; | |

Node : Count_Type) return Count_Type | |

is | |

-- CLR p. 248 | |

X : Count_Type := Node; | |

Y : Count_Type; | |

begin | |

loop | |

Y := Right (Tree.Nodes (X)); | |

if Y = 0 then | |

return X; | |

end if; | |

X := Y; | |

end loop; | |

end Max; | |

--------- | |

-- Min -- | |

--------- | |

function Min | |

(Tree : Tree_Type'Class; | |

Node : Count_Type) return Count_Type | |

is | |

-- CLR p. 248 | |

X : Count_Type := Node; | |

Y : Count_Type; | |

begin | |

loop | |

Y := Left (Tree.Nodes (X)); | |

if Y = 0 then | |

return X; | |

end if; | |

X := Y; | |

end loop; | |

end Min; | |

---------- | |

-- Next -- | |

---------- | |

function Next | |

(Tree : Tree_Type'Class; | |

Node : Count_Type) return Count_Type | |

is | |

begin | |

-- CLR p. 249 | |

if Node = 0 then | |

return 0; | |

end if; | |

if Right (Tree.Nodes (Node)) /= 0 then | |

return Min (Tree, Right (Tree.Nodes (Node))); | |

end if; | |

declare | |

X : Count_Type := Node; | |

Y : Count_Type := Parent (Tree.Nodes (Node)); | |

begin | |

while Y /= 0 and then X = Right (Tree.Nodes (Y)) loop | |

X := Y; | |

Y := Parent (Tree.Nodes (Y)); | |

end loop; | |

return Y; | |

end; | |

end Next; | |

-------------- | |

-- Previous -- | |

-------------- | |

function Previous | |

(Tree : Tree_Type'Class; | |

Node : Count_Type) return Count_Type | |

is | |

begin | |

if Node = 0 then | |

return 0; | |

end if; | |

if Left (Tree.Nodes (Node)) /= 0 then | |

return Max (Tree, Left (Tree.Nodes (Node))); | |

end if; | |

declare | |

X : Count_Type := Node; | |

Y : Count_Type := Parent (Tree.Nodes (Node)); | |

begin | |

while Y /= 0 and then X = Left (Tree.Nodes (Y)) loop | |

X := Y; | |

Y := Parent (Tree.Nodes (Y)); | |

end loop; | |

return Y; | |

end; | |

end Previous; | |

-------------------------- | |

-- Rebalance_For_Insert -- | |

-------------------------- | |

procedure Rebalance_For_Insert | |

(Tree : in out Tree_Type'Class; | |

Node : Count_Type) | |

is | |

-- CLR p. 268 | |

N : Nodes_Type renames Tree.Nodes; | |

X : Count_Type := Node; | |

pragma Assert (X /= 0); | |

pragma Assert (Color (N (X)) = Red); | |

Y : Count_Type; | |

begin | |

while X /= Tree.Root and then Color (N (Parent (N (X)))) = Red loop | |

if Parent (N (X)) = Left (N (Parent (N (Parent (N (X)))))) then | |

Y := Right (N (Parent (N (Parent (N (X)))))); | |

if Y /= 0 and then Color (N (Y)) = Red then | |

Set_Color (N (Parent (N (X))), Black); | |

Set_Color (N (Y), Black); | |

Set_Color (N (Parent (N (Parent (N (X))))), Red); | |

X := Parent (N (Parent (N (X)))); | |

else | |

if X = Right (N (Parent (N (X)))) then | |

X := Parent (N (X)); | |

Left_Rotate (Tree, X); | |

end if; | |

Set_Color (N (Parent (N (X))), Black); | |

Set_Color (N (Parent (N (Parent (N (X))))), Red); | |

Right_Rotate (Tree, Parent (N (Parent (N (X))))); | |

end if; | |

else | |

pragma Assert (Parent (N (X)) = | |

Right (N (Parent (N (Parent (N (X))))))); | |

Y := Left (N (Parent (N (Parent (N (X)))))); | |

if Y /= 0 and then Color (N (Y)) = Red then | |

Set_Color (N (Parent (N (X))), Black); | |

Set_Color (N (Y), Black); | |

Set_Color (N (Parent (N (Parent (N (X))))), Red); | |

X := Parent (N (Parent (N (X)))); | |

else | |

if X = Left (N (Parent (N (X)))) then | |

X := Parent (N (X)); | |

Right_Rotate (Tree, X); | |

end if; | |

Set_Color (N (Parent (N (X))), Black); | |

Set_Color (N (Parent (N (Parent (N (X))))), Red); | |

Left_Rotate (Tree, Parent (N (Parent (N (X))))); | |

end if; | |

end if; | |

end loop; | |

Set_Color (N (Tree.Root), Black); | |

end Rebalance_For_Insert; | |

------------------ | |

-- Right_Rotate -- | |

------------------ | |

procedure Right_Rotate (Tree : in out Tree_Type'Class; Y : Count_Type) is | |

N : Nodes_Type renames Tree.Nodes; | |

X : constant Count_Type := Left (N (Y)); | |

pragma Assert (X /= 0); | |

begin | |

Set_Left (N (Y), Right (N (X))); | |

if Right (N (X)) /= 0 then | |

Set_Parent (N (Right (N (X))), Y); | |

end if; | |

Set_Parent (N (X), Parent (N (Y))); | |

if Y = Tree.Root then | |

Tree.Root := X; | |

elsif Y = Left (N (Parent (N (Y)))) then | |

Set_Left (N (Parent (N (Y))), X); | |

else | |

pragma Assert (Y = Right (N (Parent (N (Y))))); | |

Set_Right (N (Parent (N (Y))), X); | |

end if; | |

Set_Right (N (X), Y); | |

Set_Parent (N (Y), X); | |

end Right_Rotate; | |

--------- | |

-- Vet -- | |

--------- | |

function Vet (Tree : Tree_Type'Class; Index : Count_Type) return Boolean is | |

Nodes : Nodes_Type renames Tree.Nodes; | |

Node : Node_Type renames Nodes (Index); | |

begin | |

if Parent (Node) = Index | |

or else Left (Node) = Index | |

or else Right (Node) = Index | |

then | |

return False; | |

end if; | |

if Tree.Length = 0 | |

or else Tree.Root = 0 | |

or else Tree.First = 0 | |

or else Tree.Last = 0 | |

then | |

return False; | |

end if; | |

if Parent (Nodes (Tree.Root)) /= 0 then | |

return False; | |

end if; | |

if Left (Nodes (Tree.First)) /= 0 then | |

return False; | |

end if; | |

if Right (Nodes (Tree.Last)) /= 0 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 Index /= Tree.First then | |

return False; | |

end if; | |

if Parent (Node) /= 0 | |

or else Left (Node) /= 0 | |

or else Right (Node) /= 0 | |

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 /= Index and then Tree.Last /= Index then | |

return False; | |

end if; | |

end if; | |

if Left (Node) /= 0 and then Parent (Nodes (Left (Node))) /= Index then | |

return False; | |

end if; | |

if Right (Node) /= 0 and then Parent (Nodes (Right (Node))) /= Index then | |

return False; | |

end if; | |

if Parent (Node) = 0 then | |

if Tree.Root /= Index then | |

return False; | |

end if; | |

elsif Left (Nodes (Parent (Node))) /= Index | |

and then Right (Nodes (Parent (Node))) /= Index | |

then | |

return False; | |

end if; | |

return True; | |

end Vet; | |

end Ada.Containers.Red_Black_Trees.Generic_Bounded_Operations; |