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//------------------------------------------------------------------------------
// <copyright file="CacheAxisQuery.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
// <owner current="true" primary="true">Microsoft</owner>
//------------------------------------------------------------------------------
namespace MS.Internal.Xml.XPath {
using System;
using System.Xml;
using System.Xml.XPath;
using System.Diagnostics;
using System.Collections.Generic;
internal abstract class CacheAxisQuery : BaseAxisQuery {
// int count; -- we reusing it here
protected List<XPathNavigator> outputBuffer;
public CacheAxisQuery(Query qyInput, string name, string prefix, XPathNodeType typeTest) : base(qyInput, name, prefix, typeTest) {
this.outputBuffer = new List<XPathNavigator>();
this.count = 0;
}
protected CacheAxisQuery(CacheAxisQuery other) : base(other) {
this.outputBuffer = new List<XPathNavigator>(other.outputBuffer);
this.count = other.count;
}
public override void Reset() {
this.count = 0;
}
public override object Evaluate(XPathNodeIterator context) {
base.Evaluate(context);
outputBuffer.Clear();
return this;
}
public override XPathNavigator Advance() {
Debug.Assert(0 <= count && count <= outputBuffer.Count);
if (count < outputBuffer.Count) {
return outputBuffer[count++];
}
return null;
}
public override XPathNavigator Current {
get {
Debug.Assert(0 <= count && count <= outputBuffer.Count);
if (count == 0) {
return null;
}
return outputBuffer[count - 1];
}
}
public override int CurrentPosition { get { return count; } }
public override int Count { get { return outputBuffer.Count; } }
public override QueryProps Properties { get { return QueryProps.Merge | QueryProps.Cached | QueryProps.Position | QueryProps.Count; } }
}
}
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