shadowsocks-libev/libipset/bdd/reachable.c

/* -*- coding: utf-8 -*-
 * ----------------------------------------------------------------------
 * Copyright © 2010-2013, RedJack, LLC.
 * All rights reserved.
 *
 * Please see the LICENSE.txt file in this distribution for license
 * details.
 * ----------------------------------------------------------------------
 */

#include <libcork/core.h>
#include <libcork/ds.h>

#include "ipset/bdd/nodes.h"
#include "ipset/logging.h"


size_t
ipset_node_reachable_count(const struct ipset_node_cache *cache,
                           ipset_node_id node)
{
    /* Create a set to track when we've visited a given node. */
    struct cork_hash_table  *visited = cork_pointer_hash_table_new(0, 0);

    /* And a queue of nodes to check. */
    cork_array(ipset_node_id)  queue;
    cork_array_init(&queue);

    if (ipset_node_get_type(node) == IPSET_NONTERMINAL_NODE) {
        DEBUG("Adding node %u to queue", node);
        cork_array_append(&queue, node);
    }

    /* And somewhere to store the result. */
    size_t  node_count = 0;

    /* Check each node in turn. */
    while (!cork_array_is_empty(&queue)) {
        ipset_node_id  curr = cork_array_at(&queue, --queue.size);

        /* We don't have to do anything if this node is already in the
         * visited set. */
        if (cork_hash_table_get(visited, (void *) (uintptr_t) curr) == NULL) {
            DEBUG("Visiting node %u for the first time", curr);

            /* Add the node to the visited set. */
            cork_hash_table_put
                (visited, (void *) (uintptr_t) curr,
                 (void *) (uintptr_t) true, NULL, NULL, NULL);

            /* Increase the node count. */
            node_count++;

            /* And add the node's nonterminal children to the visit
             * queue. */
            struct ipset_node  *node =
                ipset_node_cache_get_nonterminal(cache, curr);

            if (ipset_node_get_type(node->low) == IPSET_NONTERMINAL_NODE) {
                DEBUG("Adding node %u to queue", node->low);
                cork_array_append(&queue, node->low);
            }

            if (ipset_node_get_type(node->high) == IPSET_NONTERMINAL_NODE) {
                DEBUG("Adding node %u to queue", node->high);
                cork_array_append(&queue, node->high);
            }
        }
    }

    /* Return the result, freeing everything before we go. */
    cork_hash_table_free(visited);
    cork_array_done(&queue);
    return node_count;
}


size_t
ipset_node_memory_size(const struct ipset_node_cache *cache,
                       ipset_node_id node)
{
    return ipset_node_reachable_count(cache, node) * sizeof(struct ipset_node);
}