public void Add(IterableLinkedListNode <T> node)
{
if (_start == null)
{
Debug.Assert(_end == null);
_start = node;
_end = _start;
}
else
{
foreach (var cursor in _cursorsWaiting)
{
node.CursorsIncoming.Add(cursor);
cursor._next = node;
}
_end.Next = node;
node.Prev = _end;
_end = node;
}
if (!_lookup.ContainsKey(node.Value))
{
_lookup.Add(node.Value, node);
}
}
private void SetNext(IterableLinkedListNode <T> next)
{
// remove from old CursorsIncoming
if (_next != null)
{
Debug.Assert(_next.CursorsIncoming.Contains(this));
_next.CursorsIncoming.Remove(this);
}
// Add to new CursorsIncoming
if (next != null)
{
next.CursorsIncoming.Add(this);
}
// Cursor is now waiting for more
if (next == null && !_waitingList.Contains(this))
{
_waitingList.Add(this);
}
// Cursor was waiting and now has something to read
if (next != null && _waitingList.Contains(this))
{
_waitingList.Remove(this);
}
_next = next;
}
public IterableLinkedList()
{
_lookup = new Dictionary <T, IterableLinkedListNode <T> >();
_start = null;
_end = null;
_cursorsWaiting = new HashSet <IterableLinkedListCursor <T> >();
}
public IterableLinkedListCursor(IterableLinkedListNode <T> node, HashSet <IterableLinkedListCursor <T> > waitingList)
{
_node = null;
_waitingList = waitingList;
SetNext(node);
}
/// <summary>
/// Must call this first before GetCurrent
/// </summary>
/// <returns></returns>
public bool MoveNext()
{
if (_next == null)
{
return(false);
}
_node = _next;
SetNext(_node.Next);
return(true);
}
/// <summary>
/// Move to the end of the list. This means this node will get picked by all cursors, including the ones who read it
/// before
/// </summary>
public void Promote(IterableLinkedListNode <T> node)
{
if (node == null)
{
throw new ArgumentNullException();
}
var value = node.Value;
if (!_lookup.ContainsKey(value))
{
throw new ArgumentOutOfRangeException();
}
if (_end == node) // tell all cursors to read this again
{
foreach (var curosr in _cursorsWaiting)
{
node.CursorsIncoming.Add(curosr);
curosr._next = node;
}
return;
}
Debug.Assert(node.Next != null); // since we exclude last nodes
var prev = node.Prev;
var next = node.Next;
var last = _end;
// fix cursors
foreach (var cursor in node.CursorsIncoming)
{
node.Next.CursorsIncoming.Add(cursor);
cursor._next = node.Next;
}
node.CursorsIncoming.Clear();
// take out
node.Next = null;
node.Prev = null;
if (prev != null)
{
prev.Next = next;
}
else // this must be start node !
{
Debug.Assert(node == _start);
_start = next;
}
next.Prev = prev;
// attach to end
Add(node);
}
