source: branches/crossvalidation-2434/HeuristicLab.ExtLibs/HeuristicLab.NRefactory/5.5.0/NRefactory.Xml-5.5.0/ObjectIterator.cs @ 14875

// Copyright (c) 2009-2013 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;
using System.Collections.Generic;

namespace ICSharpCode.NRefactory.Xml
{
  /// <summary>
  /// Iterates through an internal object tree.
  /// </summary>
  sealed class ObjectIterator
  {
    Stack<InternalObject[]> listStack = new Stack<InternalObject[]>();
    Stack<int> indexStack = new Stack<int>();
    
    InternalObject[] objects;
    int currentIndex;
    InternalObject currentObject;
    int currentPosition;
    internal bool StopAtElementEnd;
    bool isAtElementEnd;
    
    public ObjectIterator(InternalObject[] objects, int startPosition = 0)
    {
      this.currentPosition = startPosition;
      this.objects = objects;
      if (objects.Length > 0)
        this.currentObject = objects[0];
    }
    
    public InternalObject CurrentObject {
      get { return currentObject; }
    }
    
    public int CurrentPosition {
      get { return currentPosition; }
    }
    
    public bool IsAtElementEnd {
      get { return isAtElementEnd; }
    }
    
    public int Depth {
      get { return listStack.Count; }
    }
    
    public void MoveNext()
    {
      if (currentObject == null)
        return;
      currentIndex++;
      currentPosition += currentObject.Length;
      isAtElementEnd = false;
      while (currentIndex >= objects.Length && listStack.Count > 0) {
        objects = listStack.Pop();
        currentIndex = indexStack.Pop();
        if (this.StopAtElementEnd) {
          isAtElementEnd = true;
          break;
        } else {
          currentIndex++;
        }
      }
      currentObject = (currentIndex < objects.Length ? objects[currentIndex] : null);
    }
    
    public void MoveInto()
    {
      if (isAtElementEnd || !(currentObject is InternalElement)) {
        MoveNext();
      } else {
        listStack.Push(objects);
        indexStack.Push(currentIndex);
        objects = currentObject.NestedObjects;
        currentIndex = 0;
        currentObject = objects[0];
      }
    }
    
    /// <summary>
    /// Skips all nodes in front of 'position'
    /// </summary>
    public void SkipTo(int position)
    {
      while (currentObject != null && currentPosition < position) {
        if (currentPosition + currentObject.Length <= position)
          MoveNext();
        else
          MoveInto();
      }
    }
  }
}