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);
}
public ulong GetChildByHash(byte h)
{
return((ChildrenMask & (1u << h)) == 0 ? 0ul : _children[BitsUtils.PositionOf(ChildrenMask, h)]);
}