static int
save_visit_node(struct save_data *save_data,
ipset_node_id node_id, serialized_id *dest)
{
/* Check whether we've already serialized this node. */
struct cork_hash_table_entry *entry;
bool is_new;
entry = cork_hash_table_get_or_create
(save_data->serialized_ids, (void *) (uintptr_t) node_id, &is_new);
if (!is_new) {
*dest = (intptr_t) entry->value;
return 0;
} else {
if (ipset_node_get_type(node_id) == IPSET_TERMINAL_NODE) {
/* For terminals, there isn't really anything to do — we
* just output the terminal node and use its value as the
* serialized ID. */
ipset_value value = ipset_terminal_value(node_id);
DEBUG("Writing terminal(%d)", value);
rii_check(save_data->write_terminal(save_data, value));
entry->value = (void *) (intptr_t) value;
*dest = value;
return 0;
} else {
/* For nonterminals, we drill down into the node's children
* first, then output the nonterminal node. */
struct ipset_node *node =
ipset_node_cache_get_nonterminal(save_data->cache, node_id);
DEBUG("Visiting node %u nonterminal(x%u? %u: %u)",
node_id, node->variable, node->high, node->low);
/* Output the node's nonterminal children before we output
* the node itself. */
serialized_id serialized_low;
serialized_id serialized_high;
rii_check(save_visit_node(save_data, node->low, &serialized_low));
rii_check(save_visit_node(save_data, node->high, &serialized_high));
/* Output the nonterminal */
serialized_id result = save_data->next_serialized_id--;
DEBUG("Writing node %u as serialized node %d = (x%u? %d: %d)",
node_id, result,
node->variable, serialized_low, serialized_high);
entry->value = (void *) (intptr_t) result;
*dest = result;
return save_data->write_nonterminal
(save_data, result, node->variable,
serialized_low, serialized_high);
}
}
}
static int
write_footer_v1(struct save_data *save_data,
struct ipset_node_cache *cache, ipset_node_id root)
{
/* If the root is a terminal node, then we output the terminal value
* in place of the (nonexistent) list of nonterminal nodes. */
if (ipset_node_get_type(root) == IPSET_TERMINAL_NODE) {
ipset_value value = ipset_terminal_value(root);
return write_uint32(save_data->stream, value);
}
return 0;
}
/**
* Add the given node ID to the node stack, and trace down from it
* until we find a terminal node. Assign values to the variables for
* each nonterminal that encounter along the way. We check low edges
* first, so each new variable we encounter will be assigned FALSE.
* (The high edges will be checked eventually by a call to the
* ipset_bdd_iterator_advance() function.)
*/
static void
add_node(struct ipset_bdd_iterator *iterator, ipset_node_id node_id)
{
/* Keep tracing down low edges until we reach a terminal. */
while (ipset_node_get_type(node_id) == IPSET_NONTERMINAL_NODE) {
/* Add this nonterminal node to the stack, and trace down
* further into the tree. We check low edges first, so set the
* node's variable to FALSE in the assignment. */
struct ipset_node *node =
ipset_node_cache_get_nonterminal(iterator->cache, node_id);
cork_array_append(&iterator->stack, node_id);
ipset_assignment_set(iterator->assignment, node->variable, false);
node_id = node->low;
}
/* Once we find a terminal node, save it away in the iterator result
* and return. */
iterator->value = ipset_terminal_value(node_id);
}
static ipset_node_id_t
cached_ite(ipset_node_cache_t *cache,
ipset_node_id_t f,
ipset_node_id_t g,
ipset_node_id_t h)
{
g_d_debug("Applying ITE(%p,%p,%p)", f, g, h);
/*
* Some trivial cases first.
*/
/*
* If F is a terminal, then we're in one of the following two
* cases:
*
* ITE(1,G,H) = G
* ITE(0,G,H) = H
*/
if (ipset_node_get_type(f) == IPSET_TERMINAL_NODE)
{
ipset_range_t f_value = ipset_terminal_value(f);
ipset_node_id_t result = (f_value == 0)? h: g;
g_d_debug("Trivial result = %p", result);
return result;
}
/*
* ITE(F,G,G) == G
*/
if (g == h)
{
g_d_debug("Trivial result = %p", g);
return g;
}
/*
* ITE(F,1,0) = F
*/
if ((ipset_node_get_type(g) == IPSET_TERMINAL_NODE) &&
(ipset_node_get_type(h) == IPSET_TERMINAL_NODE))
{
ipset_range_t g_value = ipset_terminal_value(g);
ipset_range_t h_value = ipset_terminal_value(h);
if ((g_value == 1) && (h_value == 0))
{
g_d_debug("Trivial result = %p", f);
return f;
}
}
/*
* Check to see if we've already performed the operation on these
* operands.
*/
ipset_trinary_key_t search_key;
ipset_trinary_key_init(&search_key, f, g, h);
gpointer found_key;
gpointer found_result;
gboolean node_exists =
g_hash_table_lookup_extended(cache->ite_cache,
&search_key,
&found_key,
&found_result);
if (node_exists)
{
/*
* There's a result in the cache, so return it.
*/
g_d_debug("Existing result = %p", found_result);
return found_result;
} else {
/*
* This result doesn't exist yet. Allocate a permanent copy
* of the key. Apply the operator, add the result to the
* cache, and then return it.
*/
ipset_trinary_key_t *real_key =
g_slice_new(ipset_trinary_key_t);
memcpy(real_key, &search_key, sizeof(ipset_trinary_key_t));
ipset_node_id_t result =
apply_ite(cache, f, g, h);
g_d_debug("NEW result = %p", result);
g_hash_table_insert(cache->ite_cache, real_key, result);
return result;
}
}
