/// <summary>
/// Get merkle proof path for one node.
/// </summary>
/// <param name="index">Should be less than <see cref="LeafCount"/>.</param>
/// <returns>
/// Return null if <see cref="Root"/> is not calculated or index is not leaf node.
/// </returns>
/// <example>
/// In the tree like
/// 12
/// 10 ------ 11
/// 6 -- 7 8 -- 9
/// 0-1 2-3 4-5
/// For leaf [4], the returned <see cref="MerklePath.Path"/> is {5, 9, 10}.
/// </example>
public MerklePath GenerateMerklePath(int index)
{
if (Root == null || index >= LeafCount)
{
return(null);
}
List <Hash> path = new List <Hash>();
int firstInRow = 0;
int rowcount = LeafCount;
while (index < Nodes.Count - 1)
{
path.Add(index % 2 == 0 ? Nodes[index + 1].Clone() : Nodes[index - 1].Clone());
rowcount = rowcount % 2 == 0 ? rowcount : rowcount + 1;
int shift = (index - firstInRow) / 2;
firstInRow += rowcount;
index = firstInRow + shift;
rowcount /= 2;
}
var res = new MerklePath();
res.Path.AddRange(path);
return(res);
}
/// <summary>
/// Calculate the <see cref="BinaryMerkleTree.Root"/> with path and provided leaf.
/// </summary>
/// <param name="merklePath"></param>
/// <param name="leaf"></param>
/// <returns></returns>
public static Hash ComputeRootWith(this MerklePath merklePath, Hash leaf)
{
Hash hash = leaf.Clone();
foreach (var node in merklePath.Path)
{
hash = BinaryMerkleTree.CalculateRootFromMultiHash(new[] { hash, node });
}
return(hash);
}
public static MerklePath AddRange(this MerklePath merklePath, IEnumerable <Hash> hashes)
{
merklePath.Path.AddRange(hashes);
return(merklePath);
}
