1package de.measite.minidns.util;
 2
 3import java.io.ByteArrayOutputStream;
 4import java.io.DataInputStream;
 5import java.io.DataOutputStream;
 6import java.io.IOException;
 7import java.net.IDN;
 8import java.util.HashSet;
 9
10public class NameUtil {
11
12    public static int size(String name) {
13        return name.length() + 2;
14    }
15
16    public static byte[] toByteArray(String name) throws IOException {
17        ByteArrayOutputStream baos = new ByteArrayOutputStream(64);
18        DataOutputStream dos = new DataOutputStream(baos);
19        for (String s: name.split("[.\u3002\uFF0E\uFF61]")) {
20            byte[] buffer = IDN.toASCII(s).getBytes();
21            dos.writeByte(buffer.length);
22            dos.write(buffer);
23        }
24        dos.writeByte(0);
25        dos.flush();
26        return baos.toByteArray();
27    }   
28
29    public static String parse(DataInputStream dis, byte data[]) 
30        throws IOException
31    {
32        int c = dis.readUnsignedByte();
33        if ((c & 0xc0) == 0xc0) {
34            c = ((c & 0x3f) << 8) + dis.readUnsignedByte();
35            HashSet<Integer> jumps = new HashSet<Integer>();
36            jumps.add(c);
37            return parse(data, c, jumps);
38        }
39        if (c == 0) {
40            return "";
41        }
42        byte b[] = new byte[c];
43        dis.readFully(b);
44        String s = IDN.toUnicode(new String(b));
45        String t = parse(dis, data);
46        if (t.length() > 0) {
47            s = s + "." + t;
48        }
49        return s;
50    }
51
52    public static String parse(
53        byte data[],
54        int offset,
55        HashSet<Integer> jumps
56    ) {
57        int c = data[offset] & 0xff;
58        if ((c & 0xc0) == 0xc0) {
59            c = ((c & 0x3f) << 8) + data[offset + 1];
60            if (jumps.contains(c)) {
61                throw new IllegalStateException("Cyclic offsets detected.");
62            }
63            jumps.add(c);
64            return parse(data, c, jumps);
65        }
66        if (c == 0) {
67            return "";
68        }
69        String s = new String(data,offset + 1, c);
70        String t = parse(data, offset + 1 + c, jumps);
71        if (t.length() > 0) {
72            s = s + "." + t;
73        }
74        return s;
75    }
76
77}