static void rbt_delete_node(rbt_t* tree, rbt_node_t* node){
rbt_node_t* descendant = NULL;
if(node->left && node->right){
descendant = rightmost_descendant(node->left);
mem_retain(descendant);
rbt_delete_node(tree, descendant);
if(node->left) node->left->parent = descendant;
if(node->right) node->right->parent = descendant;
descendant->left = node->left;
descendant->right = node->right;
descendant->color = node->color;
}else if(BLACK == rbt_node_color(node)){
//black node with at most one non-leaf child
if(RED == rbt_node_color(node->left) || RED == rbt_node_color(node->right)){
descendant = node->left ? node->left : node->right;
descendant->color = BLACK;
} else {
rbt_del_rebalance(tree, node);
}
}
rbt_node_replace(tree, node, descendant);
node->left = NULL;
node->right = NULL;
node->parent = NULL;
mem_release(node);
}
void
dec(true_type)
{
if (m_p_nd->m_type == pat_trie_head_node_type)
{
m_p_nd = static_cast<head_pointer>(m_p_nd)->m_p_max;
return;
}
node_pointer p_y = m_p_nd->m_p_parent;
while (p_y->m_type != pat_trie_head_node_type &&
get_smaller_sibling(m_p_nd) == 0)
{
m_p_nd = p_y;
p_y = p_y->m_p_parent;
}
if (p_y->m_type == pat_trie_head_node_type)
{
m_p_nd = p_y;
return;
}
m_p_nd = rightmost_descendant(get_smaller_sibling(m_p_nd));
}
static rbt_node_t* rightmost_descendant(rbt_node_t* node){
return (node->right) ? rightmost_descendant(node->right) : node;
}
