void BNode::rebalance(BNode* current_c, size_t pos_c){
if( !current_c->is_empty())
return;
if( pos_c < size_c-1 && !children[pos_c+1]->is_half() ){ //ie children[pos_c+1].size >= d+1
BNode* sibling = children[pos_c+1];
if( current_c->is_leaf() ){
Block* tmp = sibling->lost_smallest_block();
current_c ->win_block( tmp );//no rebalance needed because sibling.size >= d+1
}else{
BNode* tmp = sibling->lost_smallest_child();
current_c->win_child( tmp );
}
}else if( pos_c > 0 && !children[pos_c-1]->is_half() ){ //ie children[pos_b-1].size >= d+1
BNode* sibling = children[pos_c-1];
if( current_c->is_leaf() ){
Block* tmp = sibling->lost_greatest_block();
current_c ->win_block( tmp );
}else{
BNode* tmp = sibling->lost_greatest_child();
current_c->win_child( tmp );
}
}else{//merge
if( pos_c < size_c-1 ){ //right fusion
current_c->merge( children[pos_c+1] );
children[pos_c+1]->clear();
remove_child( pos_c+1 );
}else if( pos_c > 0){ //left fusion
children[pos_c-1]->merge( current_c );
current_c->clear();
remove_child( pos_c );
}
}
}
BTree* BTree::split(float ratio){
BTree* right = new BTree( path );
size_t blocks = root->number_blocks();
size_t number = ratio * blocks;
list<BNode*> leaves;
root->all_leaves(leaves);
Block* tmp = NULL;
for(list<BNode*>::iterator it = leaves.begin() ; it != leaves.end() ; it++)
for( size_t i = 0; i<min( (*it)->get_size_b() - d, number) ; i++){
tmp = (*it)->lost_greatest_block();
cache->remove( tmp );
right->add_block( tmp );
number--;
}
while( number > 0){
BNode* last = root->last_leave();
tmp = last->lost_greatest_block();
cache->remove( tmp );
right->add_block( tmp );
number--;
root->last_rebalance();
last = root->last_leave();
int todo = min( last->get_size_b() - d, number);
for( int i = 0; i<todo; i++){
tmp = last->lost_greatest_block();
cache->remove( tmp );
right->add_block( tmp );
number--;
}
}
return right;
}