source: branches/RemoveBackwardsCompatibility/HeuristicLab.ExtLibs/HeuristicLab.NRefactory/5.5.0/NRefactory-5.5.0/PatternMatching/Repeat.cs @ 14815

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// 
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// 
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// substantial portions of the Software.
// 
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// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
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using System;
using System.Collections.Generic;
using System.Diagnostics;

namespace ICSharpCode.NRefactory.PatternMatching
{
  /// <summary>
  /// Represents an optional node.
  /// </summary>
  public class Repeat : Pattern
  {
    readonly INode childNode;
    
    public int MinCount { get; set; }
    public int MaxCount { get; set; }
    
    public INode ChildNode {
      get { return childNode; }
    }
    
    public Repeat(INode childNode)
    {
      if (childNode == null)
        throw new ArgumentNullException("childNode");
      this.childNode = childNode;
      this.MinCount = 0;
      this.MaxCount = int.MaxValue;
    }
    
    public override bool DoMatchCollection(Role role, INode pos, Match match, BacktrackingInfo backtrackingInfo)
    {
      var backtrackingStack = backtrackingInfo.backtrackingStack;
      Debug.Assert(pos == null || pos.Role == role);
      int matchCount = 0;
      if (this.MinCount <= 0)
        backtrackingStack.Push(new PossibleMatch(pos, match.CheckPoint()));
      while (matchCount < this.MaxCount && pos != null && childNode.DoMatch(pos, match)) {
        matchCount++;
        do {
          pos = pos.NextSibling;
        } while (pos != null && pos.Role != role);
        if (matchCount >= this.MinCount)
          backtrackingStack.Push(new PossibleMatch(pos, match.CheckPoint()));
      }
      return false; // never do a normal (single-element) match; always make the caller look at the results on the back-tracking stack.
    }
    
    public override bool DoMatch(INode other, Match match)
    {
      if (other == null || other.IsNull)
        return this.MinCount <= 0;
      else
        return this.MaxCount >= 1 && childNode.DoMatch(other, match);
    }
  }
}