private Hashable initHelper(Token left, Token right, byte depth, byte max) {
if (depth == max)
// we've reached the leaves
return new Leaf();
Token midpoint = partitioner.midpoint(left, right);
Hashable lchild = initHelper(left, midpoint, inc(depth), max);
Hashable rchild = initHelper(midpoint, right, inc(depth), max);
return new Inner(midpoint, lchild, rchild);
}
private Hashable splitHelper(Hashable hashable, Token pleft, Token pright, byte depth, Token t)
throws StopRecursion.TooDeep {
if (depth >= hashdepth) throw new StopRecursion.TooDeep();
if (hashable instanceof Leaf) {
// split
size++;
Token midpoint = partitioner.midpoint(pleft, pright);
return new Inner(midpoint, new Leaf(), new Leaf());
}
// else: node.
// recurse on the matching child
Inner node = (Inner) hashable;
if (Range.contains(pleft, node.token, t))
// left child contains token
node.lchild(splitHelper(node.lchild, pleft, node.token, inc(depth), t));
else
// else: right child contains token
node.rchild(splitHelper(node.rchild, node.token, pright, inc(depth), t));
return node;
}
@Test
public void testDifference() {
int maxsize = 16;
mts = new MerkleTrees(partitioner);
mts.addMerkleTree(32, fullRange());
MerkleTrees mts2 = new MerkleTrees(partitioner);
mts2.addMerkleTree(32, fullRange());
mts.init();
mts2.init();
// add dummy hashes to both trees
for (TreeRange range : mts.invalids()) range.addAll(new HIterator(range.right));
for (TreeRange range : mts2.invalids()) range.addAll(new HIterator(range.right));
TreeRange leftmost = null;
TreeRange middle = null;
mts.maxsize(fullRange(), maxsize + 2); // give some room for splitting
// split the leftmost
Iterator<TreeRange> ranges = mts.invalids();
leftmost = ranges.next();
mts.split(leftmost.right);
// set the hashes for the leaf of the created split
middle = mts.get(leftmost.right);
middle.hash("arbitrary!".getBytes());
mts.get(partitioner.midpoint(leftmost.left, leftmost.right))
.hash("even more arbitrary!".getBytes());
// trees should disagree for (leftmost.left, middle.right]
List<Range<Token>> diffs = MerkleTrees.difference(mts, mts2);
assertEquals(diffs + " contains wrong number of differences:", 1, diffs.size());
assertTrue(diffs.contains(new Range<>(leftmost.left, middle.right)));
}