NodeEntry.java

/*
 * Copyright (c) [2016] [ <ether.camp> ]
 * This file is part of the ethereumJ library.
 *
 * The ethereumJ library is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * The ethereumJ library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with the ethereumJ library. If not, see <http://www.gnu.org/licenses/>.
 */
package org.ethereum.net.rlpx.discover.table;

import org.ethereum.net.rlpx.Node;

import static org.ethereum.crypto.HashUtil.sha3;

/**
 * Created by kest on 5/25/15.
 */
public class NodeEntry {
    private byte[] ownerId;
    Node node;
    private String entryId;
    private int distance;
    private long modified;

    public NodeEntry(Node n) {
        this.node = n;
        this.ownerId = n.getId();
        entryId = n.toString();
        distance = distance(ownerId, n.getId());
        touch();
    }

    public NodeEntry(byte[] ownerId, Node n) {
        this.node = n;
        this.ownerId = ownerId;
        entryId = n.toString();
        distance = distance(ownerId, n.getId());
        touch();
    }

    public void touch() {
        modified = System.currentTimeMillis();
    }

    public int getDistance() {
        return distance;
    }

    public String getId() {
        return entryId;
    }

    public Node getNode() {
        return node;
    }

    public long getModified() {
        return modified;
    }

    @Override
    public boolean equals(Object o) {
        boolean ret = false;

        if (o instanceof NodeEntry){
            NodeEntry e = (NodeEntry) o;
            ret = this.getId().equals(e.getId());
        }

        return ret;
    }

    @Override
    public int hashCode() {
        return this.node.hashCode();
    }

    public static int distance(byte[] ownerId, byte[] targetId) {
//        byte[] h1 = keccak(targetId);
//        byte[] h2 = keccak(ownerId);
        byte[] h1 = targetId;
        byte[] h2 = ownerId;

        byte[] hash = new byte[Math.min(h1.length, h2.length)];

        for (int i = 0; i < hash.length; i++) {
            hash[i] = (byte) (((int) h1[i]) ^ ((int) h2[i]));
        }

        int d = KademliaOptions.BINS;

        for (byte b : hash)
        {
            if (b == 0)
            {
                d -= 8;
            }
            else
            {
                int count = 0;
                for (int i = 7; i >= 0; i--)
                {
                    boolean a = (b & (1 << i)) == 0;
                    if (a)
                    {
                        count++;
                    }
                    else
                    {
                        break;
                    }
                }

                d -= count;

                break;
            }
        }
        return d;
    }
}