public IPatriciaNode <T> Modify(int key, IPatriciaOperation <T> operation)
{
if (operation == null)
{
throw new ArgumentNullException(nameof(operation));
}
if (key != Key)
{
var result = operation.OnInsert();
// This situation shouldn't occur, maybe it should throw exception instead?
if (result == null)
{
return(this);
}
// Create new leaf with new item.
var newLeaf = new PatriciaLeaf <T>(key, result);
return(PatriciaHelper.Join(Key, this, key, newLeaf));
}
else
{
// Modify item.
var result = operation.OnFound(Items);
// Remove case.
if (result == null)
{
return(null);
}
// Nothing changed.
if (result == Items)
{
return(this);
}
return(new PatriciaLeaf <T>(key, result));
}
}
public IPatriciaNode <T> Modify(int key, IPatriciaOperation <T> operation)
{
if (!PatriciaHelper.MatchPrefix(key, Prefix, Mask))
{
// Key doesn't match the prefix, so we need to create new leaf and join with it.
var item = operation.OnInsert();
// Unless operation doesn't create any item.
if (item == null)
{
return(this);
}
var leaf = new PatriciaLeaf <T>(key, item);
return(PatriciaHelper.Join(key, leaf, Prefix, this));
}
var index = PropagationIndex(key);
var child = Children[index];
var propagation = child.Modify(key, operation);
// Child item was removed.
if (propagation == null)
{
return(Children[OtherIndex(key)]);
}
// Child didn't change.
if (propagation == child)
{
return(this);
}
// Child changed.
var newChildren = Children.Change(propagation, index);
return(new PatriciaBranch <T>(Prefix, Mask, newChildren));
}