source: branches/2870_AutoDiff-nuget/HeuristicLab.ExtLibs/HeuristicLab.AvalonEdit/5.0.1/AvalonEdit-5.0.1/Document/TextAnchorNode.cs @ 18242

// 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 associated documentation 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;

namespace ICSharpCode.AvalonEdit.Document
{
  /// <summary>
  /// A TextAnchorNode is placed in the TextAnchorTree.
  /// It describes a section of text with a text anchor at the end of the section.
  /// A weak reference is used to refer to the TextAnchor. (to save memory, we derive from WeakReference instead of referencing it)
  /// </summary>
  sealed class TextAnchorNode : WeakReference
  {
    internal TextAnchorNode left, right, parent;
    internal bool color;
    internal int length;
    internal int totalLength; // totalLength = length + left.totalLength + right.totalLength
    
    public TextAnchorNode(TextAnchor anchor) : base(anchor)
    {
    }
    
    internal TextAnchorNode LeftMost {
      get {
        TextAnchorNode node = this;
        while (node.left != null)
          node = node.left;
        return node;
      }
    }
    
    internal TextAnchorNode RightMost {
      get {
        TextAnchorNode node = this;
        while (node.right != null)
          node = node.right;
        return node;
      }
    }
    
    /// <summary>
    /// Gets the inorder successor of the node.
    /// </summary>
    internal TextAnchorNode Successor {
      get {
        if (right != null) {
          return right.LeftMost;
        } else {
          TextAnchorNode node = this;
          TextAnchorNode oldNode;
          do {
            oldNode = node;
            node = node.parent;
            // go up until we are coming out of a left subtree
          } while (node != null && node.right == oldNode);
          return node;
        }
      }
    }
    
    /// <summary>
    /// Gets the inorder predecessor of the node.
    /// </summary>
    internal TextAnchorNode Predecessor {
      get {
        if (left != null) {
          return left.RightMost;
        } else {
          TextAnchorNode node = this;
          TextAnchorNode oldNode;
          do {
            oldNode = node;
            node = node.parent;
            // go up until we are coming out of a right subtree
          } while (node != null && node.left == oldNode);
          return node;
        }
      }
    }
    
    public override string ToString()
    {
      return "[TextAnchorNode Length=" + length + " TotalLength=" + totalLength + " Target=" + Target + "]";
    }
  }
}