/// <summary>
/// Implements an optimized algorithm for the following function
/// node-set difference(node-set, node-set)
/// Uses document identification and binary search,
/// based on the fact that a node-set is always in document order.
/// </summary>
/// <param name="nodeset1">An input nodeset</param>
/// <param name="nodeset2">Another input nodeset</param>
/// <returns>The those nodes that are in the node set
/// passed as the first argument that are not in the node set
/// passed as the second argument.</returns>
/// <author>Dimitre Novatchev</author>
private XPathNodeIterator difference2(XPathNodeIterator nodeset1, XPathNodeIterator nodeset2)
{
List<Pair> arDocs = new List<Pair>();
List<XPathNavigator> arNodes2 = new List<XPathNavigator>(nodeset2.Count);
while (nodeset2.MoveNext())
{
arNodes2.Add(nodeset2.Current.Clone());
}
auxEXSLT.findDocs(arNodes2, arDocs);
XPathNavigatorIterator enlResult = new XPathNavigatorIterator();
while (nodeset1.MoveNext())
{
XPathNavigator currNode = nodeset1.Current;
if (!auxEXSLT.findNode(arNodes2, arDocs, currNode))
enlResult.Add(currNode.Clone());
}
enlResult.Reset();
return enlResult;
}
/// <summary>
/// Implements the following function
/// node-set trailing(node-set, node-set)
/// </summary>
/// <param name="nodeset1"></param>
/// <param name="nodeset2"></param>
/// <returns>returns the nodes in the node set passed as the
/// first argument that follow, in document order, the first node
/// in the node set passed as the second argument</returns>
public XPathNodeIterator trailing(XPathNodeIterator nodeset1, XPathNodeIterator nodeset2)
{
XPathNavigator leader = null;
if (nodeset2.MoveNext())
{
leader = nodeset2.Current;
}
else
{
return nodeset1;
}
XPathNavigatorIterator nodelist1 = new XPathNavigatorIterator();
while (nodeset1.MoveNext())
{
if (nodeset1.Current.ComparePosition(leader) == XmlNodeOrder.After)
{
nodelist1.Add(nodeset1.Current.Clone());
}
}
nodelist1.Reset();
return nodelist1;
}
/// <summary>
/// Implements the following function
/// node-set distinct2(node-set)
///
/// This implements an optimized algorithm
/// using a Hashtable
///
/// </summary>
/// <param name="nodeset">The input nodeset</param>
/// <returns>Returns the nodes in the nodeset whose string value is
/// distinct</returns>
/// <author>Dimitre Novatchev</author>
private XPathNodeIterator distinct2(XPathNodeIterator nodeset)
{
XPathNavigatorIterator nodelist = new XPathNavigatorIterator();
Dictionary<string, string> ht = new Dictionary<string, string>(nodeset.Count / 3);
while (nodeset.MoveNext())
{
string strVal = nodeset.Current.Value;
if (!ht.ContainsKey(strVal))
{
ht.Add(strVal, "");
nodelist.Add(nodeset.Current.Clone());
}
}
nodelist.Reset();
return nodelist;
}
/// <summary>
/// Implements the following function
/// node-set intersection3(node-set, node-set)
///
/// This is an optimisation of the initial implementation
/// of intersection(). It uses a document identification
/// and a binary search algorithm, based on the fact
/// that a node-set is always in document order.
/// </summary>
/// <param name="nodeset1">The first node-set</param>
/// <param name="nodeset2">The second node-set</param>
/// <returns>The node-set, which is the intersection
/// of nodeset1 and nodeset2
/// </returns>
/// <author>Dimitre Novatchev</author>
private XPathNodeIterator intersection3(XPathNodeIterator nodeset1,
XPathNodeIterator nodeset2)
{
XPathNodeIterator it1 =
(nodeset1.Count > nodeset2.Count) ? nodeset1
: nodeset2;
XPathNodeIterator it2 =
(nodeset1.Count > nodeset2.Count) ? nodeset2
: nodeset1;
List<Pair> arDocs = new List<Pair>();
List<XPathNavigator> arNodes1 = new List<XPathNavigator>(it1.Count);
while (it1.MoveNext())
{
arNodes1.Add(it1.Current.Clone());
}
auxEXSLT.findDocs(arNodes1, arDocs);
XPathNavigatorIterator enlResult = new XPathNavigatorIterator();
while (it2.MoveNext())
{
XPathNavigator currNode = it2.Current;
if (auxEXSLT.findNode(arNodes1, arDocs, currNode))
enlResult.Add(currNode.Clone());
}
enlResult.Reset();
return enlResult;
}
/// <summary>
/// Implements the following function
/// node-set distinct(node-set)
/// </summary>
/// <param name="nodeset">The input nodeset</param>
/// <returns>Returns the nodes in the nodeset whose string value is
/// distinct</returns>
public XPathNodeIterator distinct(XPathNodeIterator nodeset)
{
if (nodeset.Count > 15)
return distinct2(nodeset);
//else
XPathNavigatorIterator nodelist = new XPathNavigatorIterator();
while (nodeset.MoveNext())
{
if (!nodelist.ContainsValue(nodeset.Current.Value))
{
nodelist.Add(nodeset.Current.Clone());
}
}
nodelist.Reset();
return nodelist;
}
