1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.compress.archivers.sevenz;
18
19 import java.util.Arrays;
20
21 /**
22 * The (partially) supported compression/encryption methods used in 7z archives.
23 * <p>
24 * All methods with a {@code _FILTER} suffix are used as preprocessors with the goal of creating a better compression ratio with the compressor that comes next
25 * in the chain of methods. 7z will in general only allow them to be used together with a "real" compression method but Commons Compress doesn't enforce this.
26 * </p>
27 * <p>
28 * The {@code BCJ_} filters work on executable files for the given platform and convert relative addresses to absolute addresses in CALL instructions. This
29 * means they are only useful when applied to executables of the chosen platform.
30 * </p>
31 */
32 public enum SevenZMethod {
33
34 /** No compression at all. */
35 COPY(new byte[] { (byte) 0x00 }),
36
37 /** LZMA - only supported when reading. */
38 LZMA(new byte[] { (byte) 0x03, (byte) 0x01, (byte) 0x01 }),
39
40 /** LZMA2. */
41 LZMA2(new byte[] { (byte) 0x21 }),
42
43 /** Deflate. */
44 DEFLATE(new byte[] { (byte) 0x04, (byte) 0x01, (byte) 0x08 }),
45
46 /**
47 * Deflate64.
48 *
49 * @since 1.16
50 */
51 DEFLATE64(new byte[] { (byte) 0x04, (byte) 0x01, (byte) 0x09 }),
52
53 /** BZIP2. */
54 BZIP2(new byte[] { (byte) 0x04, (byte) 0x02, (byte) 0x02 }),
55
56 /**
57 * AES encryption with a key length of 256 bit using SHA256 for hashes - only supported when reading.
58 */
59 AES256SHA256(new byte[] { (byte) 0x06, (byte) 0xf1, (byte) 0x07, (byte) 0x01 }),
60
61 /**
62 * BCJ x86 platform version 1.
63 *
64 * @since 1.8
65 */
66 BCJ_X86_FILTER(new byte[] { 0x03, 0x03, 0x01, 0x03 }),
67
68 /**
69 * BCJ PowerPC platform.
70 *
71 * @since 1.8
72 */
73 BCJ_PPC_FILTER(new byte[] { 0x03, 0x03, 0x02, 0x05 }),
74
75 /**
76 * BCJ I64 platform.
77 *
78 * @since 1.8
79 */
80 BCJ_IA64_FILTER(new byte[] { 0x03, 0x03, 0x04, 0x01 }),
81
82 /**
83 * BCJ ARM platform.
84 *
85 * @since 1.8
86 */
87 BCJ_ARM_FILTER(new byte[] { 0x03, 0x03, 0x05, 0x01 }),
88
89 /**
90 * BCJ ARM Thumb platform.
91 *
92 * @since 1.8
93 */
94 BCJ_ARM_THUMB_FILTER(new byte[] { 0x03, 0x03, 0x07, 0x01 }),
95
96 /**
97 * BCJ Sparc platform.
98 *
99 * @since 1.8
100 */
101 BCJ_SPARC_FILTER(new byte[] { 0x03, 0x03, 0x08, 0x05 }),
102
103 /**
104 * Delta filter.
105 *
106 * @since 1.8
107 */
108 DELTA_FILTER(new byte[] { 0x03 });
109
110 static SevenZMethod byId(final byte[] id) {
111 for (final SevenZMethod method : SevenZMethod.class.getEnumConstants()) {
112 if (Arrays.equals(method.id, id)) {
113 return method;
114 }
115 }
116 return null;
117 }
118
119 private final byte[] id;
120
121 SevenZMethod(final byte[] id) {
122 this.id = id;
123 }
124
125 byte[] getId() {
126 return Arrays.copyOf(id, id.length);
127 }
128 }