Changed: refactored binary tree to seperate tree from data
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parent
48f62eeab7
commit
0fe601e3aa
279
X2UtTrees.pas
279
X2UtTrees.pas
@ -14,6 +14,7 @@ type
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EBTKeyExists = class(Exception);
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EBTKeyNotFound = class(Exception);
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EBTCursorEof = class(Exception);
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EBTNoCursor = class(Exception);
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{** Internal representation of a binary tree node.
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*
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@ -45,19 +46,15 @@ type
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* Trees implement a descendant to traverse through the tree.
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*}
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TX2BTCustomCursor = class(TObject)
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private
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FRoot: PX2BTNode;
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protected
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function GetCurrentNode(): PX2BTNode; virtual; abstract;
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function GetCurrentKey(): Cardinal; virtual; abstract;
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function GetEof(): Boolean; virtual; abstract;
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public
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constructor Create(const ARoot: PX2BTNode); virtual;
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procedure First(); virtual; abstract;
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procedure Next(); virtual; abstract;
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property CurrentNode: PX2BTNode read GetCurrentNode;
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property Eof: Boolean read GetEof;
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property CurrentKey: Cardinal read GetCurrentKey;
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end;
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TX2BTCursorClass = class of TX2BTCustomCursor;
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@ -70,39 +67,69 @@ type
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*}
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TX2BTDefaultCursor = class(TX2BTCustomCursor)
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private
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FRoot: PX2BTNode;
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FNode: PX2BTNode;
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protected
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function GetCurrentNode(): PX2BTNode; override;
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function GetCurrentNode(): PX2BTNode;
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function GetCurrentKey(): Cardinal; override;
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function GetEof(): Boolean; override;
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public
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constructor Create(const ARoot: PX2BTNode); virtual;
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procedure First(); override;
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procedure Next(); override;
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property CurrentNode: PX2BTNode read GetCurrentNode;
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end;
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{** Binary Tree implementation.
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{** Abstract tree manager.
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*
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* Implements the basic binary tree operations, allowing room for descendants
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* to implement data storage and node management.
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* Trees implement a descendant to manage the tree nodes. This is where the
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* actual tree is stored, and possibly optimized. All tree managers are
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* assumed to store a 32-bit unsigned integer key with optional data.
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*}
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TX2BinaryTree = class(TObject)
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TX2BTCustomManager = class(TObject)
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private
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FCursor: TX2BTCustomCursor;
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protected
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function GetCurrentKey(): Cardinal; virtual;
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function GetEof(): Boolean; virtual;
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procedure CursorNeeded(); virtual; abstract;
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procedure InvalidateCursor(); virtual; abstract;
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property Cursor: TX2BTCustomCursor read FCursor write FCursor;
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public
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constructor Create(); virtual;
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destructor Destroy(); override;
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procedure Clear(); virtual; abstract;
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procedure Insert(const AKey: Cardinal); virtual; abstract;
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procedure Delete(const AKey: Cardinal); virtual; abstract;
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function Exists(const AKey: Cardinal): Boolean; virtual; abstract;
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function GetData(const AKey: Cardinal): Pointer; virtual; abstract;
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procedure First(); virtual;
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procedure Next(); virtual;
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property CurrentKey: Cardinal read GetCurrentKey;
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property Eof: Boolean read GetEof;
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end;
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TX2BTManagerClass = class of TX2BTCustomManager;
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{** Default tree manager.
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*}
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TX2BTDefaultManager = class(TX2BTCustomManager)
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private
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FRoot: PX2BTNode;
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FLastNode: PX2BTNode;
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function GetCurrentKey(): Cardinal;
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function GetEof(): Boolean;
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protected
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procedure CursorNeeded();
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procedure InvalidateCursor();
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//property Root: PX2BTNode read FRoot write FRoot;
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protected
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// Methods which don't really need to be virtual
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// (if you have a good reason; share it with me so I can make it
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// virtual, until then it's kept normal for performance reasons)
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procedure ClearNodes();
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procedure CursorNeeded(); override;
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procedure InvalidateCursor(); override;
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function FindLowestNode(const ANode: PX2BTNode): PX2BTNode;
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function FindHighestNode(const ANode: PX2BTNode): PX2BTNode;
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@ -113,17 +140,31 @@ type
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function RightChild(const ANode: PX2BTNode): Boolean;
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procedure SwapNodes(const ANode1, ANode2: PX2BTNode);
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// Virtual methods (commonly needed in descendants)
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function GetCursorClass(): TX2BTCursorClass; virtual;
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procedure DeleteCleanNode(var ANode: PX2BTNode); virtual;
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procedure AllocateNode(var ANode: PX2BTNode); virtual;
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procedure DeallocateNode(var ANode: PX2BTNode); virtual;
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public
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procedure Clear(); override;
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procedure Insert(const AKey: Cardinal); override;
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procedure Delete(const AKey: Cardinal); override;
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procedure InsertNode(const AKey: Cardinal); virtual;
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procedure DeleteNode(const AKey: Cardinal); virtual;
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function Exists(const AKey: Cardinal): Boolean; override;
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function GetData(const AKey: Cardinal): Pointer; override;
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end;
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procedure DeleteCleanNode(var ANode: PX2BTNode); virtual;
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{** Binary Tree implementation.
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*
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* Exposes the tree manager and handles node data.
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*}
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TX2BinaryTree = class(TObject)
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private
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FManager: TX2BTCustomManager;
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function GetCurrentKey(): Cardinal;
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function GetEof(): Boolean;
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protected
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function GetManagerClass(): TX2BTManagerClass; virtual;
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public
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constructor Create(); virtual;
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destructor Destroy(); override;
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@ -188,13 +229,14 @@ resourcestring
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RSBTKeyExists = 'The key "%d" already exists in the tree.';
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RSBTKeyNotFound = 'The key "%d" could not be found in the tree.';
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RSBTCursorEof = 'Cursor is at Eof.';
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RSBTNoCursor = 'Cursor not initialized, call First before Next.';
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{====================== TX2BTCustomCursor
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Initialization
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{===================== TX2BTDefaultCursor
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Traversal
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========================================}
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constructor TX2BTCustomCursor.Create;
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constructor TX2BTDefaultCursor.Create;
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begin
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inherited Create();
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@ -202,9 +244,6 @@ begin
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end;
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{===================== TX2BTDefaultCursor
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Traversal
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========================================}
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procedure TX2BTDefaultCursor.First;
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begin
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FNode := FRoot;
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@ -254,83 +293,79 @@ begin
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Result := FNode;
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end;
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function TX2BTDefaultCursor.GetCurrentKey;
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begin
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Result := CurrentNode^.Key;
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end;
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function TX2BTDefaultCursor.GetEof;
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begin
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Result := not Assigned(FNode);
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end;
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{========================== TX2BinaryTree
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{===================== TX2BTCustomManager
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Initialization
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========================================}
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constructor TX2BinaryTree.Create;
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constructor TX2BTCustomManager.Create;
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begin
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inherited;
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end;
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destructor TX2BinaryTree.Destroy;
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destructor TX2BTCustomManager.Destroy;
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begin
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ClearNodes();
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Clear();
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FreeAndNil(FCursor);
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inherited;
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end;
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{========================== TX2BinaryTree
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Interface
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========================================}
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procedure TX2BinaryTree.Clear;
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begin
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ClearNodes();
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end;
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function TX2BinaryTree.Exists;
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begin
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Result := Assigned(FindNodeOnly(AKey));
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end;
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procedure TX2BinaryTree.Insert;
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begin
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InsertNode(AKey);
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end;
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procedure TX2BinaryTree.Delete;
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begin
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DeleteNode(AKey);
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end;
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procedure TX2BinaryTree.First;
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procedure TX2BTCustomManager.First;
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begin
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CursorNeeded();
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FCursor.First();
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end;
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procedure TX2BinaryTree.Next;
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procedure TX2BTCustomManager.Next;
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begin
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CursorNeeded();
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FCursor.Next();
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end;
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{========================== TX2BinaryTree
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Internal node operations
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function TX2BTCustomManager.GetCurrentKey;
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begin
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if FCursor.Eof then
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raise EBTCursorEof.Create(RSBTCursorEof);
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Result := FCursor.CurrentKey;
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end;
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function TX2BTCustomManager.GetEof;
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begin
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Result := Assigned(FCursor) and (FCursor.Eof);
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end;
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{==================== TX2BTDefaultManager
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Node Management
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========================================}
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procedure TX2BinaryTree.AllocateNode;
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procedure TX2BTDefaultManager.AllocateNode;
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begin
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GetMem(ANode, SizeOf(TX2BTNode));
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FillChar(ANode^, SizeOf(TX2BTNode), #0);
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end;
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procedure TX2BinaryTree.DeallocateNode;
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procedure TX2BTDefaultManager.DeallocateNode;
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begin
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FreeMem(ANode, SizeOf(TX2BTNode));
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ANode := nil;
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end;
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procedure TX2BinaryTree.ClearNodes;
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procedure TX2BTDefaultManager.Clear;
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var
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pNode: PX2BTNode;
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pParent: PX2BTNode;
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@ -369,7 +404,7 @@ begin
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end;
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function TX2BinaryTree.FindHighestNode;
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function TX2BTDefaultManager.FindHighestNode;
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begin
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Result := ANode;
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@ -377,7 +412,7 @@ begin
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Result := Result^.Right;
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end;
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function TX2BinaryTree.FindLowestNode;
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function TX2BTDefaultManager.FindLowestNode;
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begin
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Result := ANode;
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@ -385,7 +420,7 @@ begin
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Result := Result^.Left;
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end;
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function TX2BinaryTree.FindNode;
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function TX2BTDefaultManager.FindNode;
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var
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pNode: PX2BTNode;
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@ -421,7 +456,7 @@ begin
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FLastNode := Result;
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end;
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function TX2BinaryTree.FindNodeOnly;
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function TX2BTDefaultManager.FindNodeOnly;
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var
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pDummy: PX2BTNode;
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@ -430,19 +465,19 @@ begin
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end;
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function TX2BinaryTree.LeftChild;
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function TX2BTDefaultManager.LeftChild;
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begin
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Assert(Assigned(ANode^.Parent), 'Node has no parent!');
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Result := (ANode^.Parent^.Left = ANode);
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end;
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function TX2BinaryTree.RightChild;
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function TX2BTDefaultManager.RightChild;
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begin
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Result := not LeftChild(ANode);
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end;
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procedure TX2BinaryTree.SwapNodes;
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procedure TX2BTDefaultManager.SwapNodes;
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procedure FixLinks(const ANode, AOld: PX2BTNode);
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begin
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if Assigned(ANode^.Parent) then
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@ -476,7 +511,7 @@ begin
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end;
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procedure TX2BinaryTree.InsertNode;
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procedure TX2BTDefaultManager.Insert;
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var
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pNode: PX2BTNode;
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pParent: PX2BTNode;
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@ -505,7 +540,7 @@ begin
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end;
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end;
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procedure TX2BinaryTree.DeleteNode;
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procedure TX2BTDefaultManager.Delete;
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var
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pNode: PX2BTNode;
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pLowest: PX2BTNode;
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@ -538,7 +573,7 @@ begin
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DeleteCleanNode(pNode);
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end;
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procedure TX2BinaryTree.DeleteCleanNode;
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procedure TX2BTDefaultManager.DeleteCleanNode;
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var
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pParent: PX2BTNode;
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pChild: PX2BTNode;
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@ -574,35 +609,97 @@ begin
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end;
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procedure TX2BinaryTree.CursorNeeded;
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function TX2BTDefaultManager.Exists;
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begin
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if not Assigned(FCursor) then
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FCursor := GetCursorClass().Create(FRoot);
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Result := Assigned(FindNodeOnly(AKey));
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end;
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procedure TX2BinaryTree.InvalidateCursor;
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function TX2BTDefaultManager.GetData;
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begin
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//! Implement GetData
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end;
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procedure TX2BTDefaultManager.CursorNeeded;
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begin
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if not Assigned(FCursor) then
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FCursor := TX2BTDefaultCursor.Create(FRoot);
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end;
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procedure TX2BTDefaultManager.InvalidateCursor;
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begin
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FreeAndNil(FCursor);
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end;
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function TX2BinaryTree.GetCursorClass;
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{========================== TX2BinaryTree
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Initialization
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========================================}
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constructor TX2BinaryTree.Create;
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begin
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Result := TX2BTDefaultCursor;
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inherited;
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FManager := GetManagerClass().Create();
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end;
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destructor TX2BinaryTree.Destroy;
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begin
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FreeAndNil(FManager);
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inherited;
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end;
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{========================== TX2BinaryTree
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Interface
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========================================}
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procedure TX2BinaryTree.Clear;
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begin
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FManager.Clear();
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end;
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function TX2BinaryTree.Exists;
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begin
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Result := FManager.Exists(AKey);
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end;
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procedure TX2BinaryTree.Insert;
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begin
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FManager.Insert(AKey);
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end;
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procedure TX2BinaryTree.Delete;
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begin
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FManager.Delete(AKey);
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end;
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procedure TX2BinaryTree.First;
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begin
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FManager.First();
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end;
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procedure TX2BinaryTree.Next;
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begin
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FManager.Next();
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end;
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function TX2BinaryTree.GetManagerClass;
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begin
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Result := TX2BTDefaultManager;
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end;
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function TX2BinaryTree.GetCurrentKey;
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begin
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if Eof then
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raise EBTCursorEof.Create(RSBTCursorEof);
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Result := FCursor.CurrentNode^.Key;
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Result := FManager.CurrentKey;
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end;
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function TX2BinaryTree.GetEof;
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begin
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Result := Assigned(FCursor) and (FCursor.Eof);
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Result := FManager.Eof;
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end;
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end.
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