mcs/class/referencesource/System.Xml/System/Xml/XPath/XPathNavigatorKeyComparer.cs

   1 //------------------------------------------------------------------------------
   2 // <copyright file="XmlNavigatorReader.cs" company="Microsoft">
   3 //     Copyright (c) Microsoft Corporation.  All rights reserved.
   4 // </copyright>
   5 // <owner current="true" primary="true">Microsoft</owner>
   6 //------------------------------------------------------------------------------
   7
   8 using System.IO;
   9 using System.Xml.Schema;
  10 using System.Collections;
  11 using System.Diagnostics;
  12 using MS.Internal.Xml.Cache;
  13
  14 namespace System.Xml.XPath {
  15     internal class XPathNavigatorKeyComparer : IEqualityComparer {
  16         bool IEqualityComparer.Equals( Object obj1, Object obj2 ) {
  17             XPathNavigator nav1 = obj1 as XPathNavigator;
  18             XPathNavigator nav2 = obj2 as XPathNavigator;
  19             if( ( nav1 != null ) && ( nav2 != null ) ) {
  20                 if( nav1.IsSamePosition( nav2 ) )
  21                     return true;
  22             }
  23             return false;
  24         }
  25
  26         int IEqualityComparer.GetHashCode ( Object obj ) {
  27             int hashCode;
  28             XPathNavigator nav;
  29             XPathDocumentNavigator xpdocNav;
  30
  31             if (obj == null) {
  32                 throw new ArgumentNullException("obj");
  33             }
  34             else if ( null != (xpdocNav = obj as XPathDocumentNavigator) ) {
  35                 hashCode = xpdocNav.GetPositionHashCode();
  36             }
  37             else if( null != (nav = obj as XPathNavigator) ) {
  38                 Object underlyingObject = nav.UnderlyingObject;
  39                 if (underlyingObject != null) {
  40                     hashCode = underlyingObject.GetHashCode();
  41                 }
  42                 else {
  43                     hashCode = (int)nav.NodeType;
  44                     hashCode ^= nav.LocalName.GetHashCode();
  45                     hashCode ^= nav.Prefix.GetHashCode();
  46                     hashCode ^= nav.NamespaceURI.GetHashCode();
  47                 }
  48             }
  49             else {
  50                 hashCode = obj.GetHashCode();
  51             }
  52             return hashCode;
  53         }
  54     }
  55 }