    001/*
    002 *  Licensed to the Apache Software Foundation (ASF) under one or more
    003 *  contributor license agreements.  See the NOTICE file distributed with
    004 *  this work for additional information regarding copyright ownership.
    005 *  The ASF licenses this file to You under the Apache License, Version 2.0
    006 *  (the "License"); you may not use this file except in compliance with
    007 *  the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 *  Unless required by applicable law or agreed to in writing, software
    012 *  distributed under the License is distributed on an "AS IS" BASIS,
    013 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 *  See the License for the specific language governing permissions and
    015 *  limitations under the License.
    016 */
    017package org.apache.commons.compress.archivers.sevenz;
    018
    019import java.util.Arrays;
    020
    021/**
    022 * The (partially) supported compression/encryption methods used in 7z archives.
    023 * <p>
    024 * 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
    025 * 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.
    026 * </p>
    027 * <p>
    028 * The {@code BCJ_} filters work on executable files for the given platform and convert relative addresses to absolute addresses in CALL instructions. This
    029 * means they are only useful when applied to executables of the chosen platform.
    030 * </p>
    031 */
    032public enum SevenZMethod {
    033
    034    /** No compression at all. */
    035    COPY(new byte[] { (byte) 0x00 }),
    036
    037    /** LZMA - only supported when reading. */
    038    LZMA(new byte[] { (byte) 0x03, (byte) 0x01, (byte) 0x01 }),
    039
    040    /** LZMA2. */
    041    LZMA2(new byte[] { (byte) 0x21 }),
    042
    043    /** Deflate. */
    044    DEFLATE(new byte[] { (byte) 0x04, (byte) 0x01, (byte) 0x08 }),
    045
    046    /**
    047     * Deflate64.
    048     *
    049     * @since 1.16
    050     */
    051    DEFLATE64(new byte[] { (byte) 0x04, (byte) 0x01, (byte) 0x09 }),
    052
    053    /** BZIP2. */
    054    BZIP2(new byte[] { (byte) 0x04, (byte) 0x02, (byte) 0x02 }),
    055
    056    /**
    057     * AES encryption with a key length of 256 bit using SHA256 for hashes - only supported when reading.
    058     */
    059    AES256SHA256(new byte[] { (byte) 0x06, (byte) 0xf1, (byte) 0x07, (byte) 0x01 }),
    060
    061    /**
    062     * BCJ x86 platform version 1.
    063     *
    064     * @since 1.8
    065     */
    066    BCJ_X86_FILTER(new byte[] { 0x03, 0x03, 0x01, 0x03 }),
    067
    068    /**
    069     * BCJ PowerPC platform.
    070     *
    071     * @since 1.8
    072     */
    073    BCJ_PPC_FILTER(new byte[] { 0x03, 0x03, 0x02, 0x05 }),
    074
    075    /**
    076     * BCJ I64 platform.
    077     *
    078     * @since 1.8
    079     */
    080    BCJ_IA64_FILTER(new byte[] { 0x03, 0x03, 0x04, 0x01 }),
    081
    082    /**
    083     * BCJ ARM platform.
    084     *
    085     * @since 1.8
    086     */
    087    BCJ_ARM_FILTER(new byte[] { 0x03, 0x03, 0x05, 0x01 }),
    088
    089    /**
    090     * BCJ ARM Thumb platform.
    091     *
    092     * @since 1.8
    093     */
    094    BCJ_ARM_THUMB_FILTER(new byte[] { 0x03, 0x03, 0x07, 0x01 }),
    095
    096    /**
    097     * BCJ Sparc platform.
    098     *
    099     * @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}