private ulong ModifyInternalNode(ulong id, InternalNode node, byte h, ulong value, byte[]?valueHash)
{
if (value == 0 && node.GetChildByHash(h) != 0 && node.Children.Count() == 2)
{
// we have to handle case when one of two children is deleted and internal node is folded to leaf
var secondChild = node.Children.First(child => child != node.GetChildByHash(h));
// fold only if secondChild is also a leaf
if (GetNodeById(secondChild).Type == NodeType.Leaf)
{
return(secondChild);
}
}
if (value != 0 && node.GetChildByHash(h) != 0 && node.Children.Count() == 1 && GetNodeById(value).Type == NodeType.Leaf)
{
return(value);
}
var modified = InternalNode.ModifyChildren(
node, h, value,
node.Children.Select(id => GetNodeById(id)?.Hash ?? throw new InvalidOperationException()),
valueHash
);
if (modified == null)
{
return(0u);
}
var newId = _versionFactory.NewVersion();
_nodeCache[newId] = modified;
return(newId);
}
public static IHashTrieNode?ModifyChildren(
InternalNode node, byte h, ulong value, IEnumerable <byte[]> childrenHashes, byte[]?valueHash
)
{
if (node == null)
{
throw new ArgumentNullException(nameof(node));
}
var was = node.GetChildByHash(h);
if (was == value)
{
return(node);
}
List <byte[]> newHashes;
var newNode = new InternalNode();
var pos = (int)BitsUtils.PositionOf(node.ChildrenMask, h);
if (was == 0)
{
if (valueHash is null)
{
throw new ArgumentNullException(nameof(valueHash));
}
newNode._children = new ulong[node._children.Length + 1];
for (var i = 0; i <= node._children.Length; ++i)
{
newNode._children[i] = i < pos ? node._children[i] : (i == pos ? value : node._children[i - 1]);
}
newNode.ChildrenMask = node.ChildrenMask | (1u << h);
newHashes = childrenHashes.ToList();
newHashes.Insert(pos, valueHash);
newNode.UpdateHash(newHashes, GetChildrenLabels(newNode.ChildrenMask));
return(newNode);
}
if (value == 0)
{
if (node._children.Length == 1)
{
return(null);
}
newNode._children = new ulong[node._children.Length - 1];
for (var i = 0; i + 1 < node._children.Length; ++i)
{
newNode._children[i] = i < pos ? node._children[i] : node._children[i + 1];
}
newNode.ChildrenMask = node.ChildrenMask ^ (1u << h);
newHashes = childrenHashes.ToList();
newHashes.RemoveAt(pos);
newNode.UpdateHash(newHashes, GetChildrenLabels(newNode.ChildrenMask));
return(newNode);
}
newNode._children = node._children.ToArray();
newNode.ChildrenMask = node.ChildrenMask;
newNode._children[pos] = value;
newHashes = childrenHashes.ToList();
newHashes[pos] = valueHash ?? throw new ArgumentNullException(nameof(valueHash));
newNode.UpdateHash(newHashes, GetChildrenLabels(newNode.ChildrenMask));
return(newNode);
}
