1 /*
2 * Copyright 2012 The Netty Project
3 *
4 * The Netty Project licenses this file to you under the Apache License,
5 * version 2.0 (the "License"); you may not use this file except in compliance
6 * with the License. You may obtain a copy of the License at:
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations
14 * under the License.
15 */
16 package org.jboss.netty.handler.codec.socks;
17
18 final class SocksCommonUtils {
19 public static final SocksRequest UNKNOWN_SOCKS_REQUEST = new UnknownSocksRequest();
20 public static final SocksResponse UNKNOWN_SOCKS_RESPONSE = new UnknownSocksResponse();
21
22 private static final int SECOND_ADDRESS_OCTET_SHIFT = 16;
23 private static final int FIRST_ADDRESS_OCTET_SHIFT = 24;
24 private static final int THIRD_ADDRESS_OCTET_SHIFT = 8;
25 private static final int XOR_DEFAULT_VALUE = 0xff;
26
27 /**
28 * A constructor to stop this class being constructed.
29 */
30 private SocksCommonUtils() {
31 //NOOP
32 }
33
34 public static String intToIp(int i) {
35 return String.valueOf(i >> FIRST_ADDRESS_OCTET_SHIFT & XOR_DEFAULT_VALUE) + '.' +
36 (i >> SECOND_ADDRESS_OCTET_SHIFT & XOR_DEFAULT_VALUE) + '.' +
37 (i >> THIRD_ADDRESS_OCTET_SHIFT & XOR_DEFAULT_VALUE) + '.' +
38 (i & XOR_DEFAULT_VALUE);
39 }
40
41 private static final char[] ipv6conseqZeroFiller = {':', ':'};
42 private static final char ipv6hextetSeparator = ':';
43
44 /*
45 * Convert numeric IPv6 to compressed format, where
46 * the longest sequence of 0's (with 2 or more 0's) is replaced with "::"
47 */
48 public static String ipv6toCompressedForm(byte[] src) {
49 assert src.length == 16;
50 //Find the longest sequence of 0's
51 //start of compressed region (hextet index)
52 int cmprHextet = -1;
53 //length of compressed region
54 int cmprSize = 0;
55 for (int hextet = 0; hextet < 8;) {
56 int curByte = hextet * 2;
57 int size = 0;
58 while (curByte < src.length && src[curByte] == 0
59 && src[curByte + 1] == 0) {
60 curByte += 2;
61 size++;
62 }
63 if (size > cmprSize) {
64 cmprHextet = hextet;
65 cmprSize = size;
66 }
67 hextet = curByte / 2 + 1;
68 }
69 if (cmprHextet == -1 || cmprSize < 2) {
70 //No compression can be applied
71 return ipv6toStr(src);
72 }
73 StringBuilder sb = new StringBuilder(39);
74 ipv6toStr(sb, src, 0, cmprHextet);
75 sb.append(ipv6conseqZeroFiller);
76 ipv6toStr(sb, src, cmprHextet + cmprSize, 8);
77 return sb.toString();
78 }
79
80 /*
81 * Convert numeric IPv6 to standard (non-compressed) format.
82 *
83 * Borrowed from Inet6Address.java #numericToTextFormat(byte[])
84 * Changed StringBuffer -> StringBuilder and ":" -> ':' for performance.
85 */
86 public static String ipv6toStr(byte[] src) {
87 assert src.length == 16;
88 StringBuilder sb = new StringBuilder(39);
89 ipv6toStr(sb, src, 0, 8);
90 return sb.toString();
91 }
92
93 private static void ipv6toStr(StringBuilder sb, byte[] src,
94 int fromHextet, int toHextet) {
95 for (int i = fromHextet; i < toHextet; i++) {
96 sb.append(Integer.toHexString(src[i << 1] << 8 & 0xff00
97 | src[(i << 1) + 1] & 0xff));
98 if (i < toHextet - 1) {
99 sb.append(ipv6hextetSeparator);
100 }
101 }
102 }
103 }
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