/*
* Insert an item to the tree.
* Return 0 if a new node was created, 1 if a node was updated, or -1 on error.
*/
int
mtree_trie_insert(struct mtree_trie *trie, const char *key, void *item)
{
struct mtree_trie_node *u;
struct mtree_trie_node *node;
size_t bit;
assert(trie != NULL);
assert(item != NULL);
assert(key != NULL && *key != '\0');
u = find_node(trie, key);
if (u != NULL && strcmp(u->key, key) == 0) {
/*
* Already in the trie, just update the item.
*/
if (trie->free_fn != NULL && u->item != NULL)
trie->free_fn(u->item);
u->item = item;
return (1);
}
if ((node = create_node(key, item)) == NULL)
return (-1);
if (u == NULL) {
/*
* Trie is empty, insert to the left under the head.
*/
for (bit = 0; KEY_BIT(key, node->key_len, bit) == 0; bit++)
;
node->bit = bit;
node->left = trie->top;
trie->top->left = node;
} else {
for (bit = 0;; bit++) {
int kbit = KEY_BIT(key, node->key_len, bit);
if (kbit != KEY_BIT(u->key, u->key_len, bit)) {
if (kbit == 0)
node->right = NULL;
else
node->left = NULL;
node->bit = bit;
break;
}
}
trie->top->left = insert_node(trie->top->left, node, trie->top);
}
return (0);
}
static struct mtree_trie *
insert_node(struct mtree_trie *u, struct mtree_trie *node, struct mtree_trie *prev)
{
if (u->bit >= node->bit || u->bit <= prev->bit) {
if (node->left == node)
node->right = u;
else
node->left = u;
return (node);
}
if (KEY_BIT(node->key, node->key_len, u->bit) == 0)
u->left = insert_node(u->left, node, u);
else
u->right = insert_node(u->right, node, u);
return (u);
}
static struct mtree_trie_node *
find_node(struct mtree_trie *trie, const char *key)
{
struct mtree_trie_node *u;
size_t len;
size_t d;
if (trie->top->left == trie->top)
return (NULL);
u = trie->top->left;
len = strlen(key);
do {
d = u->bit;
u = KEY_BIT(key, len, d) == 0 ? u->left : u->right;
} while (u != NULL && u->bit > d);
return (u);
}
