int
binheap_insert(binheap_t *bh, void *key, size_t klen, void *value)
{
binomial_tree_node_t *node = calloc(1, sizeof(binomial_tree_node_t));
node->bh = bh;
node->key = malloc(klen);
memcpy(node->key, key, klen);
node->klen = klen;
node->value = value;
int order = 0;
binomial_tree_node_t *tree = list_shift_value(bh->trees);
while (tree && tree->num_children == order) {
if (HAS_PRECEDENCE(bh, node->key, node->klen, tree->key, tree->klen)) {
binomial_tree_merge(node, tree);
} else {
binomial_tree_merge(tree, node);
node = tree;
}
order++;
tree = list_shift_value(bh->trees);
}
if (tree)
list_unshift_value(bh->trees, tree);
list_unshift_value(bh->trees, node);
bh->count++;
if (!bh->head)
bh->head = node;
else
UPDATE_HEAD(bh);
return 0;
}
// merge two heaps in a single iteration
binheap_t *binheap_merge(binheap_t *bh1, binheap_t *bh2)
{
if (bh1->mode != bh2->mode) {
// refuse to merge binomial heaps initialized with different operational modes
// TODO - error message
return NULL;
}
linked_list_t *new_list = list_create();
binomial_tree_node_t *node1 = list_shift_value(bh1->trees);
binomial_tree_node_t *node2 = list_shift_value(bh2->trees);
binomial_tree_node_t *carry = NULL;
while (node1 || node2 || carry) {
if (carry) {
// if we have a carry (merged tree from previous iteration)
// lets check if either node1 or node2 is of the same order and
// in case let's merge it before comparing node1 with node2 so
// we get rid of the carry as soon as possible
binomial_tree_node_t *node = NULL;
if (node1 && node1->num_children == carry->num_children) {
node = node1;
} else if (node2 && node2->num_children == carry->num_children) {
node = node2;
} else {
if (!node1 && !node2) {
// if we have the carry but there is neither node1 nor node2
// we can just add the carry to the list and forget about it
list_push_value(new_list, carry);
carry = NULL;
continue;
}
// if either node1 or node2 is of an higher order than the carry,
// let's swap it so that we will always compare the lower order trees
// among the three (node1, node2 and carry)
if (node1 && node1->num_children > carry->num_children) {
binomial_tree_node_t *tmp = node1;
node1 = carry;
carry = tmp;
} else if (node2 && node2->num_children > carry->num_children) {
binomial_tree_node_t *tmp = node2;
node2 = carry;
carry = tmp;
}
}
if (node) {
if (HAS_PRECEDENCE(bh1, node->key, node->klen, carry->key, carry->klen)) {
binomial_tree_merge(node, carry);
} else {
binomial_tree_merge(carry, node);
if (node == node1)
node1 = carry;
else
node2 = carry;
}
carry = NULL;
}
}
// we have already taken care of the carry here
// so now if either node1 or node2 is missing
// we can just add the other to the list and go ahead
if (node1 && !node2) {
list_push_value(new_list, node1);
node1 = list_shift_value(bh1->trees);
continue;
} else if (node2 && !node1) {
list_push_value(new_list, node2);
node2 = list_shift_value(bh2->trees);
continue;
} else if (carry && !node1 && !node2) {
// XXX - this case should have already been handled earlier
// (we have a carry but neither node1 nor node2)
list_push_value(new_list, carry);
carry = NULL;
continue;
}
int order1 = node1->num_children;
int order2 = node2->num_children;
// compare node1 and node2 and if they are of different orders
// let's add the lower one to the list and go ahead
if (order1 < order2) {
list_push_value(new_list, node1);
node1 = list_shift_value(bh1->trees);
continue;
} else if (order1 > order2) {
list_push_value(new_list, node2);
node2 = list_shift_value(bh2->trees);
continue;
}
// if we are here node1 and node2 have the same order so they
// need to be merged
if (HAS_PRECEDENCE(bh1, node1->key, node1->klen, node2->key, node2->klen)) {
binomial_tree_merge(node1, node2);
if (carry) {
if (bh1->cbs->cmp(node1->key, node1->klen, carry->key, carry->klen) >= 0) {
binomial_tree_merge(node1, carry);
carry = node1;
} else {
binomial_tree_merge(carry, node1);
}
} else {
carry = node1;
}
} else {
binomial_tree_merge(node2, node1);
if (carry) {
if (HAS_PRECEDENCE(bh1, node2->key, node2->klen, carry->key, carry->klen)) {
binomial_tree_merge(node2, carry);
carry = node2;
} else {
binomial_tree_merge(carry, node2);
}
} else {
carry = node2;
}
}
// the two trees (node1 and node2) have been merged and put into carry,
// so let's get the next two nodes (if any) and go ahead
node1 = list_shift_value(bh1->trees);
node2 = list_shift_value(bh2->trees);
}
binheap_t *merged_heap = calloc(1, sizeof(binheap_t));
merged_heap->mode = bh1->mode;
merged_heap->trees = new_list;
merged_heap->count = bh1->count + bh2->count;
merged_heap->cbs = bh1->cbs;
return merged_heap;
}
tagged_value_t *
shift_tagged_value(linked_list_t *list)
{
return (tagged_value_t *)list_shift_value(list);
}