1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * https://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19 package org.apache.commons.compress.archivers.sevenz;
20
21 import java.util.Arrays;
22
23 /**
24 * Enumerates the (partially) supported compression/encryption methods used in 7z archives.
25 * <p>
26 * 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
27 * 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.
28 * </p>
29 * <p>
30 * The {@code BCJ_} filters work on executable files for the given platform and convert relative addresses to absolute addresses in CALL instructions. This
31 * means they are only useful when applied to executables of the chosen platform.
32 * </p>
33 */
34 public enum SevenZMethod {
35
36 /** No compression at all. */
37 COPY(new byte[] { (byte) 0x00 }),
38
39 /** LZMA - only supported when reading. */
40 LZMA(new byte[] { (byte) 0x03, (byte) 0x01, (byte) 0x01 }),
41
42 /** LZMA2. */
43 LZMA2(new byte[] { (byte) 0x21 }),
44
45 /** Deflate. */
46 DEFLATE(new byte[] { (byte) 0x04, (byte) 0x01, (byte) 0x08 }),
47
48 /**
49 * Deflate64.
50 *
51 * @since 1.16
52 */
53 DEFLATE64(new byte[] { (byte) 0x04, (byte) 0x01, (byte) 0x09 }),
54
55 /** BZIP2. */
56 BZIP2(new byte[] { (byte) 0x04, (byte) 0x02, (byte) 0x02 }),
57
58 /**
59 * AES encryption with a key length of 256 bit using SHA256 for hashes - only supported when reading.
60 */
61 AES256SHA256(new byte[] { (byte) 0x06, (byte) 0xf1, (byte) 0x07, (byte) 0x01 }),
62
63 /**
64 * BCJ x86 platform version 1.
65 *
66 * @since 1.8
67 */
68 BCJ_X86_FILTER(new byte[] { 0x03, 0x03, 0x01, 0x03 }),
69
70 /**
71 * BCJ PowerPC platform.
72 *
73 * @since 1.8
74 */
75 BCJ_PPC_FILTER(new byte[] { 0x03, 0x03, 0x02, 0x05 }),
76
77 /**
78 * BCJ I64 platform.
79 *
80 * @since 1.8
81 */
82 BCJ_IA64_FILTER(new byte[] { 0x03, 0x03, 0x04, 0x01 }),
83
84 /**
85 * BCJ ARM platform.
86 *
87 * @since 1.8
88 */
89 BCJ_ARM_FILTER(new byte[] { 0x03, 0x03, 0x05, 0x01 }),
90
91 /**
92 * BCJ ARM Thumb platform.
93 *
94 * @since 1.8
95 */
96 BCJ_ARM_THUMB_FILTER(new byte[] { 0x03, 0x03, 0x07, 0x01 }),
97
98 /**
99 * BCJ Sparc platform.
100 *
101 * @since 1.8
102 */
103 BCJ_SPARC_FILTER(new byte[] { 0x03, 0x03, 0x08, 0x05 }),
104
105 /**
106 * Delta filter.
107 *
108 * @since 1.8
109 */
110 DELTA_FILTER(new byte[] { 0x03 });
111
112 static SevenZMethod byId(final byte[] id) {
113 for (final SevenZMethod method : SevenZMethod.class.getEnumConstants()) {
114 if (Arrays.equals(method.id, id)) {
115 return method;
116 }
117 }
118 return null;
119 }
120
121 private final byte[] id;
122
123 SevenZMethod(final byte[] id) {
124 this.id = id;
125 }
126
127 byte[] getId() {
128 return Arrays.copyOf(id, id.length);
129 }
130 }