public virtual int Add(object value)
{
if (internalhead == null)
{
internalhead = new LinkNode(value);
internaltail = internalhead;
}
else
{
// Added this code because internaltail seems to be null in come cases
if (internaltail == null)
{
internaltail = internalhead;
while(internaltail.Next != null)
internaltail = internaltail.Next;
}
internaltail.Next = new LinkNode(value, null, internaltail);
internaltail = internaltail.Next;
}
return internalcount++;
}
public virtual void AddFirst(object value)
{
if (internalhead == null)
{
internalhead = new LinkNode(value);
}
else
{
internalhead = new LinkNode(value, internalhead, null);
}
internalcount++;
}
public virtual int AddLast(object value)
{
if (internalhead == null)
{
internalhead = new LinkNode(value);
}
else
{
LinkNode p, q;
for(p = internalhead; (q = p.Next) != null; p = q) ;
p.Next = new LinkNode(value, null, p);
}
return internalcount++;
}
public void Reset()
{
_current = internalhead;
_isFirst = true;
}
public bool MoveNext()
{
if (_current == null) return false;
if (!_isFirst)
{
_current = _current.Next;
}
else
{
_isFirst = false;
}
return _current != null;
}
public LinkNode(object value, LinkNode next, LinkNode prev)
{
_value = value;
_next = next;
_prev = prev;
}
public LinkedListEnumerator(LinkNode node)
{
internalhead = node;
Reset();
}
public virtual void Remove(object value)
{
if (internalhead != null)
{
if (internalhead.Value.Equals(value))
{
if (internalhead == internaltail) internaltail = null;
internalhead = internalhead.Next;
internalcount--;
}
else if (internaltail.Value.Equals(value))
{
internaltail.Previous.Next = null;
internaltail = internaltail.Previous;
internalcount--;
}
else
{
LinkNode node = internalhead.Next;
while(node != null)
{
if (node.Value.Equals(value))
{
node.Previous.Next = node.Next;
node.Next.Previous = node.Previous;
internalcount--;
break;
}
node = node.Next;
}
}
}
}
public virtual void Insert(int index, object value)
{
if (index == 0)
{
AddFirst(value);
}
else if (index == internalcount)
{
AddLast(value);
}
else
{
LinkNode insert = GetNode(index);
LinkNode node = new LinkNode(value, insert, insert.Previous);
insert.Previous.Next = node;
insert.Previous = node;
internalcount++;
}
}
public void Clear()
{
internalhead = internaltail = null;
internalcount = 0;
}
public bool MoveNext()
{
if (current == null) return false;
if (!isFirst)
{
current = current.Next;
}
else
{
isFirst = false;
}
return current != null;
}
public LinkNode(object value, LinkNode next, LinkNode previous)
{
this.value = value;
this.next = next;
this.previous = previous;
}
