paweld/lazarus
1
0
Fork 0
mirror of https://gitlab.com/freepascal.org/lazarus/lazarus.git synced 2025-05-05 17:52:36 +02:00
Code Issues Packages Projects Releases Wiki Activity
ce24bd7399
lazarus/components/codetools/avl_tree.pas
lazarus 2575c72711 MG: added codetools, fixed synedit unindent, fixed MCatureHandle 
git-svn-id: trunk@343 -
2001-10-09 09:46:59 +00:00

967 lines
25 KiB
ObjectPascal
Raw Blame History

{
***************************************************************************
* *
* This source is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
* This code is distributed in the hope that it will be useful, but *
* WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
* General Public License for more details. *
* *
* A copy of the GNU General Public License is available on the World *
* Wide Web at <http://www.gnu.org/copyleft/gpl.html>. You can also *
* obtain it by writing to the Free Software Foundation, *
* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
* *
***************************************************************************
Author: Mattias Gaertner
Abstract:
TAVLTree is an Average Level binary Tree. This binary tree is always
balanced, so that inserting, deleting and finding a node is performed in
O(log(#Nodes)).
}
unit AVL_Tree;
{$ifdef FPC}{$mode objfpc}{$endif}{$H+}
interface
uses Classes, SysUtils;
type
TAVLTreeNode = class
public
Parent, Left, Right: TAVLTreeNode;
Balance: integer;
Data: Pointer;
procedure Clear;
function TreeDepth: integer; // longest WAY down. e.g. only one node => 0 !
constructor Create;
destructor Destroy; override;
end;
TAVLTree = class
private
FOnCompare: TListSortCompare;
FCount: integer;
procedure BalanceAfterInsert(ANode: TAVLTreeNode);
procedure BalanceAfterDelete(ANode: TAVLTreeNode);
function FindInsertPos(Data: Pointer): TAVLTreeNode;
public
Root: TAVLTreeNode;
function Find(Data: Pointer): TAVLTreeNode;
function FindSuccessor(ANode: TAVLTreeNode): TAVLTreeNode;
function FindPrecessor(ANode: TAVLTreeNode): TAVLTreeNode;
function FindLowest: TAVLTreeNode;
function FindHighest: TAVLTreeNode;
procedure Add(ANode: TAVLTreeNode);
function Add(Data: Pointer): TAVLTreeNode;
procedure Delete(ANode: TAVLTreeNode);
procedure MoveDataLeftMost(var ANode: TAVLTreeNode);
procedure MoveDataRightMost(var ANode: TAVLTreeNode);
property OnCompare: TListSortCompare read FOnCompare write FOnCompare;
procedure Clear;
procedure FreeAndClear;
procedure FreeAndDelete(ANode: TAVLTreeNode);
property Count: integer read FCount;
function ConsistencyCheck: integer;
procedure WriteReportToStream(s: TStream; var StreamSize: integer);
function ReportAsString: string;
constructor Create(OnCompareMethod: TListSortCompare);
destructor Destroy; override;
end;
TAVLTreeNodeMemManager = class
private
FFirstFree: TAVLTreeNode;
FFreeCount: integer;
FCount: integer;
FMinFree: integer;
FMaxFreeRatio: integer;
procedure SetMaxFreeRatio(NewValue: integer);
procedure SetMinFree(NewValue: integer);
public
procedure DisposeNode(ANode: TAVLTreeNode);
function NewNode: TAVLTreeNode;
property MinimumFreeNode: integer read FMinFree write SetMinFree;
property MaximumFreeNodeRatio: integer
read FMaxFreeRatio write SetMaxFreeRatio; // in one eighth steps
property Count: integer read FCount;
procedure Clear;
constructor Create;
destructor Destroy; override;
end;
implementation
var NodeMemManager: TAVLTreeNodeMemManager;
{ TAVLTree }
function TAVLTree.Add(Data: Pointer): TAVLTreeNode;
begin
Result:=NodeMemManager.NewNode;
Result.Data:=Data;
Add(Result);
end;
procedure TAVLTree.Add(ANode: TAVLTreeNode);
// add a node. If there are already nodes with the same value it will be
// inserted rightmost
var InsertPos: TAVLTreeNode;
InsertComp: integer;
begin
ANode.Left:=nil;
ANode.Right:=nil;
inc(FCount);
if Root<>nil then begin
InsertPos:=FindInsertPos(ANode.Data);
InsertComp:=OnCompare(ANode.Data,InsertPos.Data);
ANode.Parent:=InsertPos;
if InsertComp<0 then begin
// insert to the left
InsertPos.Left:=ANode;
end else begin
// insert to the right
InsertPos.Right:=ANode;
end;
BalanceAfterInsert(ANode);
end else begin
Root:=ANode;
ANode.Parent:=nil;
end;
end;
function TAVLTree.FindLowest: TAVLTreeNode;
begin
Result:=Root;
if Result<>nil then
while Result.Left<>nil do Result:=Result.Left;
end;
function TAVLTree.FindHighest: TAVLTreeNode;
begin
Result:=Root;
if Result<>nil then
while Result.Right<>nil do Result:=Result.Right;
end;
procedure TAVLTree.BalanceAfterDelete(ANode: TAVLTreeNode);
var OldParent, OldRight, OldRightLeft, OldLeft, OldLeftRight,
OldRightLeftLeft, OldRightLeftRight, OldLeftRightLeft, OldLeftRightRight
: TAVLTreeNode;
begin
if (ANode=nil) then exit;
if ((ANode.Balance=+1) or (ANode.Balance=-1)) then exit;
OldParent:=ANode.Parent;
if (ANode.Balance=0) then begin
// Treeheight has decreased by one
if (OldParent<>nil) then begin
if(OldParent.Left=ANode) then
Inc(OldParent.Balance)
else
Dec(OldParent.Balance);
BalanceAfterDelete(OldParent);
end;
exit;
end;
if (ANode.Balance=+2) then begin
// Node is overweighted to the right
OldRight:=ANode.Right;
if (OldRight.Balance>=0) then begin
// OldRight.Balance=={0 or -1}
// rotate left
OldRightLeft:=OldRight.Left;
if (OldParent<>nil) then begin
if (OldParent.Left=ANode) then
OldParent.Left:=OldRight
else
OldParent.Right:=OldRight;
end else
Root:=OldRight;
ANode.Parent:=OldRight;
ANode.Right:=OldRightLeft;
OldRight.Parent:=OldParent;
OldRight.Left:=ANode;
if (OldRightLeft<>nil) then
OldRightLeft.Parent:=ANode;
ANode.Balance:=(1-OldRight.Balance);
Dec(OldRight.Balance);
BalanceAfterDelete(OldRight);
end else begin
// OldRight.Balance=-1
// double rotate right left
OldRightLeft:=OldRight.Left;
OldRightLeftLeft:=OldRightLeft.Left;
OldRightLeftRight:=OldRightLeft.Right;
if (OldParent<>nil) then begin
if (OldParent.Left=ANode) then
OldParent.Left:=OldRightLeft
else
OldParent.Right:=OldRightLeft;
end else
Root:=OldRightLeft;
ANode.Parent:=OldRightLeft;
ANode.Right:=OldRightLeftLeft;
OldRight.Parent:=OldRightLeft;
OldRight.Left:=OldRightLeftRight;
OldRightLeft.Parent:=OldParent;
OldRightLeft.Left:=ANode;
OldRightLeft.Right:=OldRight;
if (OldRightLeftLeft<>nil) then
OldRightLeftLeft.Parent:=ANode;
if (OldRightLeftRight<>nil) then
OldRightLeftRight.Parent:=OldRight;
if (OldRightLeft.Balance<=0) then
ANode.Balance:=0
else
ANode.Balance:=-1;
if (OldRightLeft.Balance>=0) then
OldRight.Balance:=0
else
OldRight.Balance:=+1;
OldRightLeft.Balance:=0;
BalanceAfterDelete(OldRightLeft);
end;
end else begin
// Node.Balance=-2
// Node is overweighted to the left
OldLeft:=ANode.Left;
if (OldLeft.Balance<=0) then begin
// rotate right
OldLeftRight:=OldLeft.Right;
if (OldParent<>nil) then begin
if (OldParent.Left=ANode) then
OldParent.Left:=OldLeft
else
OldParent.Right:=OldLeft;
end else
Root:=OldLeft;
ANode.Parent:=OldLeft;
ANode.Left:=OldLeftRight;
OldLeft.Parent:=OldParent;
OldLeft.Right:=ANode;
if (OldLeftRight<>nil) then
OldLeftRight.Parent:=ANode;
ANode.Balance:=(-1-OldLeft.Balance);
Inc(OldLeft.Balance);
BalanceAfterDelete(OldLeft);
end else begin
// OldLeft.Balance = 1
// double rotate left right
OldLeftRight:=OldLeft.Right;
OldLeftRightLeft:=OldLeftRight.Left;
OldLeftRightRight:=OldLeftRight.Right;
if (OldParent<>nil) then begin
if (OldParent.Left=ANode) then
OldParent.Left:=OldLeftRight
else
OldParent.Right:=OldLeftRight;
end else
Root:=OldLeftRight;
ANode.Parent:=OldLeftRight;
ANode.Left:=OldLeftRightRight;
OldLeft.Parent:=OldLeftRight;
OldLeft.Right:=OldLeftRightLeft;
OldLeftRight.Parent:=OldParent;
OldLeftRight.Left:=OldLeft;
OldLeftRight.Right:=ANode;
if (OldLeftRightLeft<>nil) then
OldLeftRightLeft.Parent:=OldLeft;
if (OldLeftRightRight<>nil) then
OldLeftRightRight.Parent:=ANode;
if (OldLeftRight.Balance>=0) then
ANode.Balance:=0
else
ANode.Balance:=+1;
if (OldLeftRight.Balance<=0) then
OldLeft.Balance:=0
else
OldLeft.Balance:=-1;
OldLeftRight.Balance:=0;
BalanceAfterDelete(OldLeftRight);
end;
end;
end;
procedure TAVLTree.BalanceAfterInsert(ANode: TAVLTreeNode);
var OldParent, OldParentParent, OldRight, OldRightLeft, OldRightRight, OldLeft,
OldLeftLeft, OldLeftRight: TAVLTreeNode;
begin
OldParent:=ANode.Parent;
if (OldParent=nil) then exit;
if (OldParent.Left=ANode) then begin
// Node is left son
dec(OldParent.Balance);
if (OldParent.Balance=0) then exit;
if (OldParent.Balance=-1) then begin
BalanceAfterInsert(OldParent);
exit;
end;
// OldParent.Balance=-2
if (ANode.Balance=-1) then begin
// rotate
OldRight:=ANode.Right;
OldParentParent:=OldParent.Parent;
if (OldParentParent<>nil) then begin
// OldParent has GrandParent. GrandParent gets new child
if (OldParentParent.Left=OldParent) then
OldParentParent.Left:=ANode
else
OldParentParent.Right:=ANode;
end else begin
// OldParent was root node. New root node
Root:=ANode;
end;
ANode.Parent:=OldParentParent;
ANode.Right:=OldParent;
OldParent.Parent:=ANode;
OldParent.Left:=OldRight;
if (OldRight<>nil) then
OldRight.Parent:=OldParent;
ANode.Balance:=0;
OldParent.Balance:=0;
end else begin
// Node.Balance = +1
// double rotate
OldParentParent:=OldParent.Parent;
OldRight:=ANode.Right;
OldRightLeft:=OldRight.Left;
OldRightRight:=OldRight.Right;
if (OldParentParent<>nil) then begin
// OldParent has GrandParent. GrandParent gets new child
if (OldParentParent.Left=OldParent) then
OldParentParent.Left:=OldRight
else
OldParentParent.Right:=OldRight;
end else begin
// OldParent was root node. new root node
Root:=OldRight;
end;
OldRight.Parent:=OldParentParent;
OldRight.Left:=ANode;
OldRight.Right:=OldParent;
ANode.Parent:=OldRight;
ANode.Right:=OldRightLeft;
OldParent.Parent:=OldRight;
OldParent.Left:=OldRightRight;
if (OldRightLeft<>nil) then
OldRightLeft.Parent:=ANode;
if (OldRightRight<>nil) then
OldRightRight.Parent:=OldParent;
if (OldRight.Balance<=0) then
ANode.Balance:=0
else
ANode.Balance:=-1;
if (OldRight.Balance=-1) then
OldParent.Balance:=1
else
OldParent.Balance:=0;
OldRight.Balance:=0;
end;
end else begin
// Node is right son
Inc(OldParent.Balance);
if (OldParent.Balance=0) then exit;
if (OldParent.Balance=+1) then begin
BalanceAfterInsert(OldParent);
exit;
end;
// OldParent.Balance = +2
if(ANode.Balance=+1) then begin
// rotate
OldLeft:=ANode.Left;
OldParentParent:=OldParent.Parent;
if (OldParentParent<>nil) then begin
// Parent has GrandParent . GrandParent gets new child
if(OldParentParent.Left=OldParent) then
OldParentParent.Left:=ANode
else
OldParentParent.Right:=ANode;
end else begin
// OldParent was root node . new root node
Root:=ANode;
end;
ANode.Parent:=OldParentParent;
ANode.Left:=OldParent;
OldParent.Parent:=ANode;
OldParent.Right:=OldLeft;
if (OldLeft<>nil) then
OldLeft.Parent:=OldParent;
ANode.Balance:=0;
OldParent.Balance:=0;
end else begin
// Node.Balance = -1
// double rotate
OldLeft:=ANode.Left;
OldParentParent:=OldParent.Parent;
OldLeftLeft:=OldLeft.Left;
OldLeftRight:=OldLeft.Right;
if (OldParentParent<>nil) then begin
// OldParent has GrandParent . GrandParent gets new child
if (OldParentParent.Left=OldParent) then
OldParentParent.Left:=OldLeft
else
OldParentParent.Right:=OldLeft;
end else begin
// OldParent was root node . new root node
Root:=OldLeft;
end;
OldLeft.Parent:=OldParentParent;
OldLeft.Left:=OldParent;
OldLeft.Right:=ANode;
ANode.Parent:=OldLeft;
ANode.Left:=OldLeftRight;
OldParent.Parent:=OldLeft;
OldParent.Right:=OldLeftLeft;
if (OldLeftLeft<>nil) then
OldLeftLeft.Parent:=OldParent;
if (OldLeftRight<>nil) then
OldLeftRight.Parent:=ANode;
if (OldLeft.Balance>=0) then
ANode.Balance:=0
else
ANode.Balance:=+1;
if (OldLeft.Balance=+1) then
OldParent.Balance:=-1
else
OldParent.Balance:=0;
OldLeft.Balance:=0;
end;
end;
end;
procedure TAVLTree.Clear;
procedure DeleteNode(ANode: TAVLTreeNode);
begin
if ANode<>nil then begin
if ANode.Left<>nil then DeleteNode(ANode.Left);
if ANode.Right<>nil then DeleteNode(ANode.Right);
end;
NodeMemManager.DisposeNode(ANode);
end;
// Clear
begin
DeleteNode(Root);
Root:=nil;
FCount:=0;
end;
constructor TAVLTree.Create(OnCompareMethod: TListSortCompare);
begin
inherited Create;
FOnCompare:=OnCompareMethod;
FCount:=0;
end;
procedure TAVLTree.Delete(ANode: TAVLTreeNode);
var OldParent, OldLeft, OldRight, Successor, OldSuccParent, OldSuccLeft,
OldSuccRight: TAVLTreeNode;
OldBalance: integer;
begin
OldParent:=ANode.Parent;
OldBalance:=ANode.Balance;
ANode.Parent:=nil;
ANode.Balance:=0;
if ((ANode.Left=nil) and (ANode.Right=nil)) then begin
// Node is Leaf (no children)
if (OldParent<>nil) then begin
// Node has parent
if (OldParent.Left=ANode) then begin
// Node is left Son of OldParent
OldParent.Left:=nil;
Inc(OldParent.Balance);
end else begin
// Node is right Son of OldParent
OldParent.Right:=nil;
Dec(OldParent.Balance);
end;
BalanceAfterDelete(OldParent);
end else begin
// Node is the only node of tree
Root:=nil;
end;
dec(FCount);
NodeMemManager.DisposeNode(ANode);
exit;
end;
if (ANode.Right=nil) then begin
// Left is only son
// and because DelNode is AVL, Right has no childrens
// replace DelNode with Left
OldLeft:=ANode.Left;
ANode.Left:=nil;
OldLeft.Parent:=OldParent;
if (OldParent<>nil) then begin
if (OldParent.Left=ANode) then begin
OldParent.Left:=OldLeft;
Inc(OldParent.Balance);
end else begin
OldParent.Right:=OldLeft;
Dec(OldParent.Balance);
end;
BalanceAfterDelete(OldParent);
end else begin
Root:=OldLeft;
end;
dec(FCount);
NodeMemManager.DisposeNode(ANode);
exit;
end;
if (ANode.Left=nil) then begin
// Right is only son
// and because DelNode is AVL, Left has no childrens
// replace DelNode with Right
OldRight:=ANode.Right;
ANode.Right:=nil;
OldRight.Parent:=OldParent;
if (OldParent<>nil) then begin
if (OldParent.Left=ANode) then begin
OldParent.Left:=OldRight;
Inc(OldParent.Balance);
end else begin
OldParent.Right:=OldRight;
Dec(OldParent.Balance);
end;
BalanceAfterDelete(OldParent);
end else begin
Root:=OldRight;
end;
dec(FCount);
NodeMemManager.DisposeNode(ANode);
exit;
end;
// DelNode has both: Left and Right
// Replace ANode with symmetric Successor
Successor:=FindSuccessor(ANode);
OldLeft:=ANode.Left;
OldRight:=ANode.Right;
OldSuccParent:=Successor.Parent;
OldSuccLeft:=Successor.Left;
OldSuccRight:=Successor.Right;
ANode.Balance:=Successor.Balance;
Successor.Balance:=OldBalance;
if (OldSuccParent<>ANode) then begin
// at least one node between ANode and Successor
ANode.Parent:=Successor.Parent;
if (OldSuccParent.Left=Successor) then
OldSuccParent.Left:=ANode
else
OldSuccParent.Right:=ANode;
Successor.Right:=OldRight;
OldRight.Parent:=Successor;
end else begin
// Successor is right son of ANode
ANode.Parent:=Successor;
Successor.Right:=ANode;
end;
Successor.Left:=OldLeft;
if OldLeft<>nil then
OldLeft.Parent:=Successor;
Successor.Parent:=OldParent;
ANode.Left:=OldSuccLeft;
if ANode.Left<>nil then
ANode.Left.Parent:=ANode;
ANode.Right:=OldSuccRight;
if ANode.Right<>nil then
ANode.Right.Parent:=ANode;
if (OldParent<>nil) then begin
if (OldParent.Left=ANode) then
OldParent.Left:=Successor
else
OldParent.Right:=Successor;
end else
Root:=Successor;
// delete Node as usual
Delete(ANode);
end;
destructor TAVLTree.Destroy;
begin
Clear;
inherited Destroy;
end;
function TAVLTree.Find(Data: Pointer): TAVLTreeNode;
var Comp: integer;
begin
Result:=Root;
while (Result<>nil) do begin
Comp:=OnCompare(Data,Result.Data);
if Comp=0 then exit;
if Comp<0 then begin
if Result.Left<>nil then
Result:=Result.Left
else
exit;
end else begin
if Result.Right<>nil then
Result:=Result.Right
else
exit;
end;
end;
end;
function TAVLTree.FindInsertPos(Data: Pointer): TAVLTreeNode;
var Comp: integer;
begin
Result:=Root;
while (Result<>nil) do begin
Comp:=OnCompare(Data,Result.Data);
if Comp<0 then begin
if Result.Left<>nil then
Result:=Result.Left
else
exit;
end else begin
if Result.Right<>nil then
Result:=Result.Right
else
exit;
end;
end;
end;
function TAVLTree.FindSuccessor(ANode: TAVLTreeNode): TAVLTreeNode;
begin
Result:=ANode.Right;
if Result<>nil then begin
while (Result.Left<>nil) do Result:=Result.Left;
end else begin
Result:=ANode;
while (Result.Parent<>nil) and (Result.Parent.Right=Result) do
Result:=Result.Parent;
Result:=Result.Parent;
end;
end;
function TAVLTree.FindPrecessor(ANode: TAVLTreeNode): TAVLTreeNode;
begin
Result:=ANode.Left;
if Result<>nil then begin
while (Result.Right<>nil) do Result:=Result.Right;
end else begin
Result:=ANode;
while (Result.Parent<>nil) and (Result.Parent.Left=Result) do
Result:=Result.Parent;
Result:=Result.Parent;
end;
end;
procedure TAVLTree.MoveDataLeftMost(var ANode: TAVLTreeNode);
var LeftMost, PreNode: TAVLTreeNode;
Data: Pointer;
begin
if ANode=nil then exit;
LeftMost:=ANode;
repeat
PreNode:=FindPrecessor(LeftMost);
if (PreNode=nil) or (FOnCompare(ANode,PreNode)<>0) then break;
LeftMost:=PreNode;
until false;
if LeftMost=ANode then exit;
Data:=LeftMost.Data;
LeftMost.Data:=ANode.Data;
ANode.Data:=Data;
ANode:=LeftMost;
end;
procedure TAVLTree.MoveDataRightMost(var ANode: TAVLTreeNode);
var RightMost, PostNode: TAVLTreeNode;
Data: Pointer;
begin
if ANode=nil then exit;
RightMost:=ANode;
repeat
PostNode:=FindSuccessor(RightMost);
if (PostNode=nil) or (FOnCompare(ANode,PostNode)<>0) then break;
RightMost:=PostNode;
until false;
if RightMost=ANode then exit;
Data:=RightMost.Data;
RightMost.Data:=ANode.Data;
ANode.Data:=Data;
ANode:=RightMost;
end;
function TAVLTree.ConsistencyCheck: integer;
var RealCount: integer;
function CheckNode(ANode: TAVLTreeNode): integer;
var LeftDepth, RightDepth: integer;
begin
if ANode=nil then begin
Result:=0;
exit;
end;
inc(RealCount);
// test left son
if ANode.Left<>nil then begin
if ANode.Left.Parent<>ANode then begin
Result:=-2; exit;
end;
if OnCompare(ANode.Left.Data,ANode.Data)>0 then begin
Result:=-3; exit;
end;
Result:=CheckNode(ANode.Left);
if Result<>0 then exit;
end;
// test right son
if ANode.Right<>nil then begin
if ANode.Right.Parent<>ANode then begin
Result:=-4; exit;
end;
if OnCompare(ANode.Data,ANode.Right.Data)>0 then begin
Result:=-5; exit;
end;
Result:=CheckNode(ANode.Right);
if Result<>0 then exit;
end;
// test balance
if ANode.Left<>nil then
LeftDepth:=ANode.Left.TreeDepth+1
else
LeftDepth:=0;
if ANode.Right<>nil then
RightDepth:=ANode.Right.TreeDepth+1
else
RightDepth:=0;
if ANode.Balance<>(RightDepth-LeftDepth) then begin
Result:=-6; exit;
end;
// ok
Result:=0;
end;
// TAVLTree.ConsistencyCheck
begin
RealCount:=0;
Result:=CheckNode(Root);
if Result<>0 then exit;
if FCount<>RealCount then begin
Result:=-1;
exit;
end;
end;
procedure TAVLTree.FreeAndClear;
procedure FreeNode(ANode: TAVLTreeNode);
begin
if ANode=nil then exit;
FreeNode(ANode.Left);
FreeNode(ANode.Right);
if ANode.Data<>nil then TObject(ANode.Data).Free;
ANode.Data:=nil;
end;
// TAVLTree.FreeAndClear
begin
// free all data
FreeNode(Root);
// free all nodes
Clear;
end;
procedure TAVLTree.FreeAndDelete(ANode: TAVLTreeNode);
var OldData: TObject;
begin
OldData:=TObject(ANode.Data);
Delete(ANode);
OldData.Free;
end;
procedure TAVLTree.WriteReportToStream(s: TStream; var StreamSize: integer);
var h: string;
procedure WriteStr(const Txt: string);
begin
if s<>nil then
s.Write(Txt[1],length(Txt));
inc(StreamSize,length(Txt));
end;
procedure WriteTreeNode(ANode: TAVLTreeNode; const Prefix: string);
var b: string;
begin
if ANode=nil then exit;
WriteTreeNode(ANode.Right,Prefix+' ');
b:=Prefix+HexStr(Cardinal(ANode.Data),8)+' '
+' Self='+HexStr(Cardinal(ANode),8)
+' Parent='+HexStr(Cardinal(ANode.Parent),8)
+' Balance='+IntToStr(ANode.Balance)
+#13#10;
WriteStr(b);
WriteTreeNode(ANode.Left,Prefix+' ');
end;
// TAVLTree.WriteReportToStream
begin
h:='Consistency: '+IntToStr(ConsistencyCheck)+' ---------------------'+#13#10;
WriteStr(h);
WriteTreeNode(Root,' ');
h:='-End-Of-AVL-Tree---------------------'+#13#10;
WriteStr(h);
end;
function TAVLTree.ReportAsString: string;
var ms: TMemoryStream;
StreamSize: integer;
begin
Result:='';
ms:=TMemoryStream.Create;
try
StreamSize:=0;
WriteReportToStream(nil,StreamSize);
ms.Size:=StreamSize;
StreamSize:=0;
WriteReportToStream(ms,StreamSize);
if ms.Size>0 then begin
ms.Position:=0;
SetLength(Result,ms.Size);
ms.Read(Result[1],ms.Size);
end;
finally
ms.Free;
end;
end;
{ TAVLTreeNode }
constructor TAVLTreeNode.Create;
begin
inherited Create;
end;
destructor TAVLTreeNode.Destroy;
begin
inherited Destroy;
end;
function TAVLTreeNode.TreeDepth: integer;
// longest WAY down. e.g. only one node => 0 !
var LeftDepth, RightDepth: integer;
begin
if Left<>nil then
LeftDepth:=Left.TreeDepth+1
else
LeftDepth:=0;
if Right<>nil then
RightDepth:=Right.TreeDepth+1
else
RightDepth:=0;
if LeftDepth>RightDepth then
Result:=LeftDepth
else
Result:=RightDepth;
end;
procedure TAVLTreeNode.Clear;
begin
Parent:=nil;
Left:=nil;
Right:=nil;
Balance:=0;
Data:=nil;
end;
{ TAVLTreeNodeMemManager }
constructor TAVLTreeNodeMemManager.Create;
begin
inherited Create;
FFirstFree:=nil;
FFreeCount:=0;
FCount:=0;
FMinFree:=100;
FMaxFreeRatio:=8; // 1:1
end;
destructor TAVLTreeNodeMemManager.Destroy;
begin
Clear;
inherited Destroy;
end;
procedure TAVLTreeNodeMemManager.DisposeNode(ANode: TAVLTreeNode);
begin
if ANode=nil then exit;
if (FFreeCount<FMinFree) or (FFreeCount<((FCount shr 3)*FMaxFreeRatio)) then
begin
// add ANode to Free list
ANode.Clear;
ANode.Right:=FFirstFree;
FFirstFree:=ANode;
inc(FFreeCount);
end else begin
// free list full -> free the ANode
ANode.Free;
end;
dec(FCount);
end;
function TAVLTreeNodeMemManager.NewNode: TAVLTreeNode;
begin
if FFirstFree<>nil then begin
// take from free list
Result:=FFirstFree;
FFirstFree:=FFirstFree.Right;
Result.Right:=nil;
end else begin
// free list empty -> create new node
Result:=TAVLTreeNode.Create;
end;
inc(FCount);
end;
procedure TAVLTreeNodeMemManager.Clear;
var ANode: TAVLTreeNode;
begin
while FFirstFree<>nil do begin
ANode:=FFirstFree;
FFirstFree:=FFirstFree.Right;
ANode.Right:=nil;
ANode.Free;
end;
FFreeCount:=0;
end;
procedure TAVLTreeNodeMemManager.SetMaxFreeRatio(NewValue: integer);
begin
if NewValue<0 then NewValue:=0;
if NewValue=FMaxFreeRatio then exit;
FMaxFreeRatio:=NewValue;
end;
procedure TAVLTreeNodeMemManager.SetMinFree(NewValue: integer);
begin
if NewValue<0 then NewValue:=0;
if NewValue=FMinFree then exit;
FMinFree:=NewValue;
end;
initialization
NodeMemManager:=TAVLTreeNodeMemManager.Create;
finalization
NodeMemManager.Free;
NodeMemManager:=nil;
end.
Reference in New Issue View Git Blame Copy Permalink