// Copyright (c) 1999-2004 Brian Wellington (bwelling@xbill.org)

package org.xbill.DNS;

import java.net.*;
import java.io.*;

/**
 * Address Record - maps a domain name to an Internet address
 *
 * @author Brian Wellington
 */

public class ARecord extends Record {

    private static final long serialVersionUID = -2172609200849142323L;

    private int addr;

    ARecord() {
    }

    Record
    getObject() {
        return new ARecord();
    }

    private static final int
    fromArray(byte[] array) {
        return (((array[0] & 0xFF) << 24) |
                ((array[1] & 0xFF) << 16) |
                ((array[2] & 0xFF) << 8) |
                (array[3] & 0xFF));
    }

    private static final byte[]
    toArray(int addr) {
        byte[] bytes = new byte[4];
        bytes[0] = (byte) ((addr >>> 24) & 0xFF);
        bytes[1] = (byte) ((addr >>> 16) & 0xFF);
        bytes[2] = (byte) ((addr >>> 8) & 0xFF);
        bytes[3] = (byte) (addr & 0xFF);
        return bytes;
    }

    /**
     * Creates an A Record from the given data
     *
     * @param address The address that the name refers to
     */
    public ARecord(Name name, int dclass, long ttl, InetAddress address) {
        super(name, Type.A, dclass, ttl);
        if (Address.familyOf(address) != Address.IPv4)
            throw new IllegalArgumentException("invalid IPv4 address");
        addr = fromArray(address.getAddress());
    }

    void
    rrFromWire(DNSInput in) throws IOException {
        addr = fromArray(in.readByteArray(4));
    }

    void
    rdataFromString(Tokenizer st, Name origin) throws IOException {
        InetAddress address = st.getAddress(Address.IPv4);
        addr = fromArray(address.getAddress());
    }

    /**
     * Converts rdata to a String
     */
    String
    rrToString() {
        return (Address.toDottedQuad(toArray(addr)));
    }

    /**
     * Returns the Internet address
     */
    public InetAddress
    getAddress() {
        try {
            return InetAddress.getByAddress(toArray(addr));
        } catch (UnknownHostException e) {
            return null;
        }
    }

    void
    rrToWire(DNSOutput out, Compression c, boolean canonical) {
        out.writeU32(((long) addr) & 0xFFFFFFFFL);
    }

}
