ptree_branch::ptree_branch(uint8_t split_pos, const ptree_ptr& p1, const ptree_ptr& p2)
: m_branches{ p1, p2 }
, m_node_count(p1->node_count() + p2->node_count())
, m_split_pos(split_pos)
, m_complete(p1->complete() && p2->complete())
{
if (p1->is_proxy()) {
// p1 is proxy, p2 must be valid, and branches are in order
m_prefix = p2->prefix();
} else if (p2->is_proxy()) {
// p2 is proxy, p1 must be valid, and branches are in order
m_prefix = p1->prefix();
} else {
// Both are valid, but might be out of order
m_prefix = p1->prefix();
if (p1->prefix() > p2->prefix()) {
swap(m_branches[0], m_branches[1]);
}
}
m_prefix.zero_above(split_pos);
m_merkle = make_digest(m_prefix, m_node_count, m_branches[0]->merkle(), m_branches[1]->merkle());
}
ptree_ptr ptree_branch::merge(ptree_ptr other) const
{
if (m_merkle != other->merkle()) {
// If there is a mismatch, fail hard
return ptree_ptr();
}
if (complete() || other->is_proxy()) {
// If I am complete, or the other side is a proxy
// pick this entry
return shared_from_this();
}
// At this point, othe side should be a branch
shared_ptr<const ptree_branch> obranch = std::dynamic_pointer_cast<const ptree_branch>(other);
if (!obranch) {
// If not, fail
return ptree_ptr();
}
// Merge both children
return make_shared<ptree_branch>(m_split_pos,
m_branches[0]->merge(obranch->m_branches[0]),
m_branches[1]->merge(obranch->m_branches[1]));
}