mcs/class/referencesource/System.Web/Util/DoubleLink.cs

   1 //------------------------------------------------------------------------------
   2 // <copyright file="DoubleLink.cs" company="Microsoft">
   3 //     Copyright (c) Microsoft Corporation.  All rights reserved.
   4 // </copyright>
   5 //------------------------------------------------------------------------------
   6
   7 /*
   8  * DoubleLink
   9  *
  10  * Copyright (c) 1998-1999, Microsoft Corporation
  11  *
  12  */
  13
  14 namespace System.Web.Util {
  15     using System.Runtime.Serialization.Formatters;
  16
  17     internal class DoubleLink {
  18         internal DoubleLink    _next, _prev;
  19         internal Object           Item;
  20
  21         internal DoubleLink() {
  22             _next = _prev = this;
  23         }
  24         internal DoubleLink(Object item)  : this() {
  25             this.Item = item;
  26         }
  27         internal DoubleLink Next {get {return _next;}}
  28
  29         internal void InsertAfter(DoubleLink after) {
  30             this._prev = after;
  31             this._next = after._next;
  32             after._next = this;
  33             this._next._prev = this;
  34         }
  35
  36         internal void InsertBefore(DoubleLink before) {
  37             this._prev = before._prev;
  38             this._next = before;
  39             before._prev = this;
  40             this._prev._next = this;
  41         }
  42
  43         internal void Remove() {
  44             this._prev._next = this._next;
  45             this._next._prev = this._prev;
  46             _next = _prev = this;
  47         }
  48
  49 #if DBG
  50         internal virtual void DebugValidate() {
  51             Debug.CheckValid(this._next != this || this._prev == this, "Invalid link");
  52         }
  53
  54         internal virtual string DebugDescription(string indent) {
  55             string desc;
  56
  57             desc = indent + "_next=" + _next + ", _prev=" + _prev + "\nItem=";
  58             desc += Debug.GetDescription(Item, indent + "    ");
  59
  60             return desc;
  61         }
  62 #endif
  63     }
  64
  65 }