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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 }