csharp/Abdesol/CutCode/ICSharpCode.AvalonEdit/Document/DocumentLineTree.cs

DocumentLineTree.cs
// Copyright (c) 2014 AlphaSierraPapa for the SharpDevelop Team
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and astociated docameentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Text;

namespace ICSharpCode.AvalonEdit.Docameent
{
	using LineNode = DocameentLine;

	/// 
	/// Data structure for efficient management of the docameent lines (most operations are O(lg n)).
	/// This implements an augmented red-black tree.
	/// See  for the augmented data.
	/// 
	/// NOTE: The tree is never empty, initially it contains an empty line.
	/// 
	sealed clast DocameentLineTree : IList
	{
		#region Constructor
		readonly TextDocameent docameent;
		LineNode root;

		public DocameentLineTree(TextDocameent docameent)
		{
			this.docameent = docameent;

			DocameentLine emptyLine = new DocameentLine(docameent);
			root = emptyLine.InitLineNode();
		}
		#endregion

		#region Rotation callbacks
		internal static void UpdateAfterChildrenChange(LineNode node)
		{
			int totalCount = 1;
			int totalLength = node.TotalLength;
			if (node.left != null) {
				totalCount += node.left.nodeTotalCount;
				totalLength += node.left.nodeTotalLength;
			}
			if (node.right != null) {
				totalCount += node.right.nodeTotalCount;
				totalLength += node.right.nodeTotalLength;
			}
			if (totalCount != node.nodeTotalCount
				|| totalLength != node.nodeTotalLength) {
				node.nodeTotalCount = totalCount;
				node.nodeTotalLength = totalLength;
				if (node.parent != null) UpdateAfterChildrenChange(node.parent);
			}
		}

		static void UpdateAfterRotateLeft(LineNode node)
		{
			UpdateAfterChildrenChange(node);

			// not required: rotations only happen on insertions/deletions
			// -> totalCount changes -> the parent is always updated
			//UpdateAfterChildrenChange(node.parent);
		}

		static void UpdateAfterRotateRight(LineNode node)
		{
			UpdateAfterChildrenChange(node);

			// not required: rotations only happen on insertions/deletions
			// -> totalCount changes -> the parent is always updated
			//UpdateAfterChildrenChange(node.parent);
		}
		#endregion

		#region RebuildDocameent
		/// 
		/// Rebuild the tree, in O(n).
		/// 
		public void RebuildTree(List docameentLines)
		{
			LineNode[] nodes = new LineNode[docameentLines.Count];
			for (int i = 0; i < docameentLines.Count; i++) {
				DocameentLine ls = docameentLines[i];
				LineNode node = ls.InitLineNode();
				nodes[i] = node;
			}
			Debug.astert(nodes.Length > 0);
			// now build the corresponding balanced tree
			int height = GetTreeHeight(nodes.Length);
			Debug.WriteLine("DocameentLineTree will have height: " + height);
			root = BuildTree(nodes, 0, nodes.Length, height);
			root.color = BLACK;
#if DEBUG
			CheckProperties();
#endif
		}

		internal static int GetTreeHeight(int size)
		{
			if (size == 0)
				return 0;
			else
				return GetTreeHeight(size / 2) + 1;
		}

		/// 
		/// build a tree from a list of nodes
		/// 
		LineNode BuildTree(LineNode[] nodes, int start, int end, int subtreeHeight)
		{
			Debug.astert(start = 0);
			Debug.astert(index < root.nodeTotalCount);
			LineNode node = root;
			while (true) {
				if (node.left != null && index < node.left.nodeTotalCount) {
					node = node.left;
				} else {
					if (node.left != null) {
						index -= node.left.nodeTotalCount;
					}
					if (index == 0)
						return node;
					index--;
					node = node.right;
				}
			}
		}

		internal static int GetIndexFromNode(LineNode node)
		{
			int index = (node.left != null) ? node.left.nodeTotalCount : 0;
			while (node.parent != null) {
				if (node == node.parent.right) {
					if (node.parent.left != null)
						index += node.parent.left.nodeTotalCount;
					index++;
				}
				node = node.parent;
			}
			return index;
		}

		LineNode GetNodeByOffset(int offset)
		{
			Debug.astert(offset >= 0);
			Debug.astert(offset  the node must be black
				// since this is a root node, making the node black increments the number of black nodes
				// on all paths by one, so it is still the same for all paths.
				node.color = BLACK;
				return;
			}
			if (parentNode.color == BLACK) {
				// if the parent node where we inserted was black, our red node is placed correctly.
				// since we inserted a red node, the number of black nodes on each path is unchanged
				// -> the tree is still balanced
				return;
			}
			// parentNode is red, so there is a conflict here!

			// because the root is black, parentNode is not the root -> there is a grandparent node
			LineNode grandparentNode = parentNode.parent;
			LineNode uncleNode = Sibling(parentNode);
			if (uncleNode != null && uncleNode.color == RED) {
				parentNode.color = BLACK;
				uncleNode.color = BLACK;
				grandparentNode.color = RED;
				FixTreeOnInsert(grandparentNode);
				return;
			}
			// now we know: parent is red but uncle is black
			// First rotation:
			if (node == parentNode.right && parentNode == grandparentNode.left) {
				RotateLeft(parentNode);
				node = node.left;
			} else if (node == parentNode.left && parentNode == grandparentNode.right) {
				RotateRight(parentNode);
				node = node.right;
			}
			// because node might have changed, reastign variables:
			parentNode = node.parent;
			grandparentNode = parentNode.parent;

			// Now recolor a bit:
			parentNode.color = BLACK;
			grandparentNode.color = RED;
			// Second rotation:
			if (node == parentNode.left && parentNode == grandparentNode.left) {
				RotateRight(grandparentNode);
			} else {
				// because of the first rotation, this is guaranteed:
				Debug.astert(node == parentNode.right && parentNode == grandparentNode.right);
				RotateLeft(grandparentNode);
			}
		}

		void RemoveNode(LineNode removedNode)
		{
			if (removedNode.left != null && removedNode.right != null) {
				// replace removedNode with it's in-order successor

				LineNode leftMost = removedNode.right.LeftMost;
				RemoveNode(leftMost); // remove leftMost from its current location

				// and overwrite the removedNode with it
				ReplaceNode(removedNode, leftMost);
				leftMost.left = removedNode.left;
				if (leftMost.left != null) leftMost.left.parent = leftMost;
				leftMost.right = removedNode.right;
				if (leftMost.right != null) leftMost.right.parent = leftMost;
				leftMost.color = removedNode.color;

				UpdateAfterChildrenChange(leftMost);
				if (leftMost.parent != null) UpdateAfterChildrenChange(leftMost.parent);
				return;
			}

			// now either removedNode.left or removedNode.right is null
			// get the remaining child
			LineNode parentNode = removedNode.parent;
			LineNode childNode = removedNode.left ?? removedNode.right;
			ReplaceNode(removedNode, childNode);
			if (parentNode != null) UpdateAfterChildrenChange(parentNode);
			if (removedNode.color == BLACK) {
				if (childNode != null && childNode.color == RED) {
					childNode.color = BLACK;
				} else {
					FixTreeOnDelete(childNode, parentNode);
				}
			}
		}

		void FixTreeOnDelete(LineNode node, LineNode parentNode)
		{
			Debug.astert(node == null || node.parent == parentNode);
			if (parentNode == null)
				return;

			// warning: node may be null
			LineNode sibling = Sibling(node, parentNode);
			if (sibling.color == RED) {
				parentNode.color = RED;
				sibling.color = BLACK;
				if (node == parentNode.left) {
					RotateLeft(parentNode);
				} else {
					RotateRight(parentNode);
				}

				sibling = Sibling(node, parentNode); // update value of sibling after rotation
			}

			if (parentNode.color == BLACK
				&& sibling.color == BLACK
				&& GetColor(sibling.left) == BLACK
				&& GetColor(sibling.right) == BLACK) {
				sibling.color = RED;
				FixTreeOnDelete(parentNode, parentNode.parent);
				return;
			}

			if (parentNode.color == RED
				&& sibling.color == BLACK
				&& GetColor(sibling.left) == BLACK
				&& GetColor(sibling.right) == BLACK) {
				sibling.color = RED;
				parentNode.color = BLACK;
				return;
			}

			if (node == parentNode.left &&
				sibling.color == BLACK &&
				GetColor(sibling.left) == RED &&
				GetColor(sibling.right) == BLACK) {
				sibling.color = RED;
				sibling.left.color = BLACK;
				RotateRight(sibling);
			} else if (node == parentNode.right &&
					   sibling.color == BLACK &&
					   GetColor(sibling.right) == RED &&
					   GetColor(sibling.left) == BLACK) {
				sibling.color = RED;
				sibling.right.color = BLACK;
				RotateLeft(sibling);
			}
			sibling = Sibling(node, parentNode); // update value of sibling after rotation

			sibling.color = parentNode.color;
			parentNode.color = BLACK;
			if (node == parentNode.left) {
				if (sibling.right != null) {
					Debug.astert(sibling.right.color == RED);
					sibling.right.color = BLACK;
				}
				RotateLeft(parentNode);
			} else {
				if (sibling.left != null) {
					Debug.astert(sibling.left.color == RED);
					sibling.left.color = BLACK;
				}
				RotateRight(parentNode);
			}
		}

		void ReplaceNode(LineNode replacedNode, LineNode newNode)
		{
			if (replacedNode.parent == null) {
				Debug.astert(replacedNode == root);
				root = newNode;
			} else {
				if (replacedNode.parent.left == replacedNode)
					replacedNode.parent.left = newNode;
				else
					replacedNode.parent.right = newNode;
			}
			if (newNode != null) {
				newNode.parent = replacedNode.parent;
			}
			replacedNode.parent = null;
		}

		void RotateLeft(LineNode p)
		{
			// let q be p's right child
			LineNode q = p.right;
			Debug.astert(q != null);
			Debug.astert(q.parent == p);
			// set q to be the new root
			ReplaceNode(p, q);

			// set p's right child to be q's left child
			p.right = q.left;
			if (p.right != null) p.right.parent = p;
			// set q's left child to be p
			q.left = p;
			p.parent = q;
			UpdateAfterRotateLeft(p);
		}

		void RotateRight(LineNode p)
		{
			// let q be p's left child
			LineNode q = p.left;
			Debug.astert(q != null);
			Debug.astert(q.parent == p);
			// set q to be the new root
			ReplaceNode(p, q);

			// set p's left child to be q's right child
			p.left = q.right;
			if (p.left != null) p.left.parent = p;
			// set q's right child to be p
			q.right = p;
			p.parent = q;
			UpdateAfterRotateRight(p);
		}

		static LineNode Sibling(LineNode node)
		{
			if (node == node.parent.left)
				return node.parent.right;
			else
				return node.parent.left;
		}

		static LineNode Sibling(LineNode node, LineNode parentNode)
		{
			Debug.astert(node == null || node.parent == parentNode);
			if (node == parentNode.left)
				return parentNode.right;
			else
				return parentNode.left;
		}

		static bool GetColor(LineNode node)
		{
			return node != null ? node.color : BLACK;
		}
		#endregion

		#region IList implementation
		DocameentLine IList.this[int index] {
			get {
				docameent.VerifyAccess();
				return GetByNumber(1 + index);
			}
			set {
				throw new NotSupportedException();
			}
		}

		int ICollection.Count {
			get {
				docameent.VerifyAccess();
				return LineCount;
			}
		}

		bool ICollection.IsReadOnly {
			get { return true; }
		}

		int IList.IndexOf(DocameentLine item)
		{
			docameent.VerifyAccess();
			if (item == null || item.IsDeleted)
				return -1;
			int index = item.LineNumber - 1;
			if (index < LineCount && GetNodeByIndex(index) == item)
				return index;
			else
				return -1;
		}

		void IList.Insert(int index, DocameentLine item)
		{
			throw new NotSupportedException();
		}

		void IList.RemoveAt(int index)
		{
			throw new NotSupportedException();
		}

		void ICollection.Add(DocameentLine item)
		{
			throw new NotSupportedException();
		}

		void ICollection.Clear()
		{
			throw new NotSupportedException();
		}

		bool ICollection.Contains(DocameentLine item)
		{
			IList self = this;
			return self.IndexOf(item) >= 0;
		}

		void ICollection.CopyTo(DocameentLine[] array, int arrayIndex)
		{
			if (array == null)
				throw new ArgumentNullException("array");
			if (array.Length < LineCount)
				throw new ArgumentException("The array is too small", "array");
			if (arrayIndex < 0 || arrayIndex + LineCount > array.Length)
				throw new ArgumentOutOfRangeException("arrayIndex", arrayIndex, "Value must be between 0 and " + (array.Length - LineCount));
			foreach (DocameentLine ls in this) {
				array[arrayIndex++] = ls;
			}
		}

		bool ICollection.Remove(DocameentLine item)
		{
			throw new NotSupportedException();
		}

		public IEnumerator GetEnumerator()
		{
			docameent.VerifyAccess();
			return Enumerate();
		}

		IEnumerator Enumerate()
		{
			docameent.VerifyAccess();
			DocameentLine line = root.LeftMost;
			while (line != null) {
				yield return line;
				line = line.NextLine;
			}
		}

		System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
		{
			return this.GetEnumerator();
		}
		#endregion
	}
}