/// <summary>
/// Builds the Merkle Tree recursivly from the list of Leaf nodes to the root node.
/// </summary>
/// <remarks>
/// Merkle tree is built from lowest level to the highest (root) level.
/// In each level nodes are paired and their parent node is constructed.
/// If there is odd number of nodes, then last parent node is calculated using same node for both childs.
/// </remarks>
/// <param name="nodes">The list of nodes.</param>
private void BuildTree(IList <MerkleNodeBase> nodes)
{
// if only one node, then we reached the root level
if (nodes.Count == 1)
{
this.root = nodes[0];
return;
}
// new list of next level nodes
var nextLevelNodes = new List <MerkleNodeBase>();
// the lenght of list where each node has a pair.
var lenghtOfPairs = (nodes.Count / 2) * 2;
// calculate next level nodes for each current level node pair
for (var i = 0; i < lenghtOfPairs; i += 2)
{
var newNode = new MerkleNode(this.hashProvider, nodes[i], nodes[i + 1]);
nextLevelNodes.Add(newNode);
}
// if there is one node left without pair (odd number of nodes), then use same node for both childs
if (nodes.Count > lenghtOfPairs)
{
var newNode = new MerkleNode(this.hashProvider, nodes[nodes.Count - 1], nodes[nodes.Count - 1]);
nextLevelNodes.Add(newNode);
}
this.BuildTree(nextLevelNodes);
}
/// <summary>
/// Initializes a new instance of the <see cref="MerkleNode"/> class.
/// </summary>
/// <param name="hashProvider">The hash provider.</param>
/// <param name="left">The left child node.</param>
/// <param name="right">The right child node.</param>
internal MerkleNode(IHashProvider hashProvider, MerkleNodeBase left, MerkleNodeBase right)
{
this.right = right;
this.left = left;
this.nodeHash = hashProvider.ComputeHash(left.Hash.GetHashBytes().Concat(right.Hash.GetHashBytes()).ToArray());
}