void* avltree_remove(avltree_t* me, void* k)
{
int i;
for (i = 0; i < me->size; ) {
long r;
node_t *n;
n = &me->nodes[i];
/* couldn't find it */
if (!n->key)
return NULL;
r = me->cmp(n->key, k);
if (r == 0) {
/* replacement */
int rep;
me->count -= 1;
k = n->key;
rep = __previous_ordered_node(me, i);
if (-1 == rep) {
/* make sure the node is now blank */
n->key = NULL;
} else {
/* have r's left node become right node of r's parent.
* NOTE: r by definition shouldn't have a right child */
__shift_up(me, __child_l(rep), __child_r(__parent(rep)));
/* have r replace deleted node */
__shift_up(me, rep, i);
}
if (i != 0)
__rebalance(me, __parent(i));
return k;
} else if (r < 0) {
i = __child_l(i);
} else if (r > 0) {
i = __child_r(i);
} else {
assert(0);
}
}
/* couldn't find it */
return NULL;
}
static int __pushup(heap_t * hp, int idx)
{
while (1)
{
int parent, compare;
/* we are now the root node */
if (0 == idx)
return idx;
parent = __parent(idx);
compare = hp->cmp(hp->array[idx], hp->array[parent], hp->udata);
/* we are smaller than the parent */
if (compare < 0)
{
return -1;
}
else
{
__swap(hp, idx, parent);
}
idx = parent;
}
return idx;
}
static void __rebalance(avltree_t* me, int idx)
{
while (1) {
if (2 <= __height(me, __child_l(idx)) - __height(me, __child_r(idx))) {
int bf_l;
bf_l = __height(me, __child_l(__child_l(idx))) -
__height(me, __child_r(__child_l(idx)));
if (bf_l == -1) {
avltree_rotate_left(me, __child_l(idx));
avltree_rotate_right(me, __child_l(idx));
} else {
avltree_rotate_right(me, __child_l(idx));
}
} else if (-2 >= __height(me, __child_l(idx)) - __height(me, __child_r(idx))) {
int bf_r;
bf_r = __height(me, __child_l(__child_r(idx))) -
__height(me, __child_r(__child_r(idx)));
if (bf_r == -1) {
avltree_rotate_left(me, __child_r(idx));
} else {
avltree_rotate_right(me, __child_r(idx));
avltree_rotate_left(me, __child_r(idx));
}
}
if (0 == idx) break;
idx = __parent(idx);
}
}
void avltree_rotate_left(avltree_t* me, int idx)
{
int p;
p = __parent(idx);
/* A Partial
* Move Y out of the way so that X can take its spot */
__shift_down(me, __child_l(p), __child_l(__child_l(p)));
memcpy(&me->nodes[__child_l(p)], &me->nodes[p], sizeof(node_t));
if (me->shift_down_callback)
me->shift_down_callback( p, __child_l(p), me->shift_up_callback_user);
/* B */
__shift_down(me, __child_l(idx), __child_r(__child_l(p)));
me->nodes[__child_l(idx)].key = NULL;
/* A Final
* Move Y into X's old spot */
__shift_up(me, idx, p);
}
void rebalance(avltree_t* me, int position)
{
return __rebalance(me, __parent(position));
}