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//------------------------------------------------------------------------------
// <copyright file="DoubleLinkList.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//------------------------------------------------------------------------------
/*
* DoubleLinkList
*
* Copyright (c) 1998-1999, Microsoft Corporation
*
*/
namespace System.Web.Util {
using System.Text;
using System.Runtime.Serialization.Formatters;
internal class DoubleLinkList : DoubleLink {
internal DoubleLinkList() {
}
internal bool IsEmpty() {
return _next == this;
}
internal virtual void InsertHead(DoubleLink entry) {
entry.InsertAfter(this);
}
internal virtual void InsertTail(DoubleLink entry) {
entry.InsertBefore(this);
}
internal DoubleLinkListEnumerator GetEnumerator() {
return new DoubleLinkListEnumerator(this);
}
#if DBG
internal override void DebugValidate() {
DoubleLink l1, l2;
base.DebugValidate();
/*
* Detect loops by moving one pointer forward 2 for every 1
* of the other.
*/
l1 = l2 = this;
for (;;) {
/* move l2 forward */
l2 = l2._next;
if (l2 == this)
break;
Debug.CheckValid(l2 != l1, "Invalid loop in list, first move.");
l2.DebugValidate();
/* move l2 forward again */
l2 = l2._next;
if (l2 == this)
break;
Debug.CheckValid(l2 != l1, "Invalid loop in list, second move.");
l2.DebugValidate();
/* move l1 forward */
l1 = l1._next;
}
}
internal override string DebugDescription(String indent) {
string desc;
DoubleLinkListEnumerator lenum;
int c;
StringBuilder sb;
string i2 = indent + " ";
if (IsEmpty()) {
desc = indent + "DoubleLinkList is empty\n";
}
else {
c = Length;
sb = new StringBuilder(indent + "DoubleLinkList has " + c + " entries.\n");
lenum = GetEnumerator();
while (lenum.MoveNext()) {
sb.Append(Debug.GetDescription(lenum.GetDoubleLink(), i2));
}
desc = sb.ToString();
}
return desc;
}
#endif
internal int Length {
get {
DoubleLinkListEnumerator lenum;
int c;
Debug.Validate(this);
c = 0;
lenum = GetEnumerator();
while (lenum.MoveNext()) {
c++;
}
return c;
}
}
}
}
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