void avl_insert(sb_avl * instance, void * key, void * data)
{
avl_node * curr_node, * prev_node, * q, * x, * y, * z;
// insert into empty AVL tree
if (avl_root(instance) == NULL) {
instance->root = avl_new_node(key, data);
instance->root->height = 1;
return;
}
curr_node = instance->root;
prev_node = instance->root;
// traverse until NULL, keeping track of the parent
while ( curr_node != NULL )
{
if ( instance->cmp_keys(key, curr_node->key ) < 0 )
{
prev_node = curr_node; // Remember prev. node
curr_node = curr_node->left; // Continue search in left subtree
}
else if ( instance->cmp_keys(key, curr_node->key ) >= 0 )
{
prev_node = curr_node; // Remember prev. node
curr_node = curr_node->right; // Continue search in right subtree
}
}
q = avl_new_node(key, data);
q->height = 1;
q->parent = prev_node;
if ( instance->cmp_keys(key, prev_node->key) < 0 ) {
prev_node->left = q;
}
else {
prev_node->right = q;
}
x = y = z = q;
while ( x != NULL ) {
if ( avl_diff_height(x->left, x->right) <= 1) {
z = y;
y = x;
x = x->parent;
}
else {
break;
}
}
if ( x != NULL ) {
avl_trinode_restructure(instance, x, y, z);
}
return;
}
/* insert an node to tree */
static avl_node_t* avl_insert_node(avl_node_t* root, avl_key_t key, void* data)
{
int rotate = 0;
if (root == NULL)
{
return avl_new_node(key, data);
}
if (key < root->key)
{
rotate = ROT_LEFT;
root->left = avl_insert_node(root->left, key, data);
}
else if (key > root->key)
{
rotate = ROT_RIGHT;
root->right = avl_insert_node(root->right, key, data);
}
else
assert(!"duplicated key insertion not supported");
/* update height */
root->height = MAX(HEIGHT(root->left), HEIGHT(root->right)) + 1;
return avl_balance_node(root, avl_get_balance(root), rotate);
}
extern int
avl_insert(node_t **rootaddr, PyObject *key, PyObject *value)
{
node_t *root = *rootaddr;
if (root == NULL) {
root = avl_new_node(key, value);
if (root == NULL)
return -1;
}
else {
node_t *it, *up[32];
int upd[32], top = 0;
int done = 0;
int cmp_res;
it = root;
for (;;) {
cmp_res = ct_compare(KEY(it), key);
if (cmp_res == 0) {
Py_XDECREF(VALUE(it));
VALUE(it) = value;
Py_INCREF(value);
return 0;
}
upd[top] = (cmp_res < 0);
up[top++] = it;
if (it->link[upd[top - 1]] == NULL)
break;
it = it->link[upd[top - 1]];
}
it->link[upd[top - 1]] = avl_new_node(key, value);
if (it->link[upd[top - 1]] == NULL)
return -1;
while (--top >= 0 && !done) {
int lh, rh, max;
cmp_res = ct_compare(KEY(up[top]), key);
lh = height(up[top]->link[upd[top]]);
rh = height(up[top]->link[!upd[top]]);
if (lh - rh == 0)
done = 1;
if (lh - rh >= 2) {
node_t *a = up[top]->link[upd[top]]->link[upd[top]];
node_t *b = up[top]->link[upd[top]]->link[!upd[top]];
if (height( a ) >= height( b ))
up[top] = avl_single(up[top], !upd[top]);
else
up[top] = avl_double(up[top], !upd[top]);
if (top != 0)
up[top - 1]->link[upd[top - 1]] = up[top];
else
root = up[0];
done = 1;
}
lh = height(up[top]->link[upd[top]]);
rh = height(up[top]->link[!upd[top]]);
max = avl_max(lh, rh);
BALANCE(up[top]) = max + 1;
}
}
(*rootaddr) = root;
return 1;
}