// do a little dance
static inline BSTreeNode *BSTree_node_delete(BSTree *map, BSTreeNode *node, void *key) {
int cmp = map->compare(node->key, key);
if (cmp < 0) {
if (node->left) {
return BSTree_node_delete(map, node->left, key);
} else {
return NULL;
}
} else if (cmp > 0) {
if (node->right) {
return BSTree_node_delete(map, node->right, key);
} else {
return NULL;
}
} else {
if (node->left && node->right) {
BSTreeNode *successor = BSTree_find_min(node->right);
BSTree_swap(successor, node);
BSTree_replace_node_in_parent(map, successor, successor->right);
return successor;
} else if (node->left) {
BSTree_replace_node_in_parent(map, node, node->left);
} else if (node->right) {
BSTree_replace_node_in_parent(map, node, node->right);
} else {
BSTree_replace_node_in_parent(map, node, NULL);
}
return node;
}
}
static inline BSTreeNode *BSTree_node_delete(BSTree *map, BSTreeNode *node,
void *key)
{
int cmp = map->compare(node->key, key);
if (cmp < 0) {
if (node->left) {
return BSTree_node_delete(map, node->left, key);
} else {
// not found
return NULL;
}
} else if (cmp > 0) {
if (node->right) {
return BSTree_node_delete(map, node->right, key);
} else {
// not found
return NULL;
}
} else {
map->count--;
if (node->left && node->right) {
// swap this node for the smallest node that is bigger than us
BSTreeNode *successor = BSTree_find_min(node->right);
BSTree_swap(successor, node);
// this leaves the old successor with possibly a right child
// so replace it with that right child
BSTree_replace_node_in_parent(map, successor, successor->right);
// finally it's swapped, so return successor instead of node
return successor;
} else if (node->left) {
BSTree_replace_node_in_parent(map, node, node->left);
} else if (node->right) {
BSTree_replace_node_in_parent(map, node, node->right);
} else {
BSTree_replace_node_in_parent(map, node, NULL);
}
return node;
}
}