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//
// System.Xml.XPath.XPathNodeIterator
//
// Author:
// Jason Diamond (jason@injektilo.org)
//
// (C) 2002 Jason Diamond http://injektilo.org/
//
//
// 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;
namespace System.Xml.XPath
{
public abstract class XPathNodeIterator : ICloneable, IEnumerable
{
private int _count = -1;
#region Constructor
protected XPathNodeIterator ()
{
}
#endregion
#region Properties
public virtual int Count
{
get
{
if (_count == -1)
{
// compute and cache the count
XPathNodeIterator tmp = Clone ();
while (tmp.MoveNext ())
;
_count = tmp.CurrentPosition;
}
return _count;
}
}
public abstract XPathNavigator Current { get; }
public abstract int CurrentPosition { get; }
#endregion
#region Methods
public abstract XPathNodeIterator Clone ();
object ICloneable.Clone ()
{
return Clone ();
}
public virtual IEnumerator GetEnumerator ()
{
return new XPathNodeIteratorEnumerator (this);
}
public abstract bool MoveNext ();
#endregion
struct XPathNodeIteratorEnumerator : IEnumerator
{
XPathNodeIterator source;
XPathNavigator current;
public XPathNodeIteratorEnumerator (XPathNodeIterator source)
{
this.source = source.Clone ();
current = null;
}
public bool MoveNext ()
{
if (!source.MoveNext ())
return false;
current = source.Current.Clone ();
return true;
}
public object Current {
get { return current; }
}
public void Reset ()
{
throw new NotSupportedException ();
}
}
}
}
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