    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 *
    024 * <p>All methods with a _FILTER suffix are used as preprocessors with
    025 * the goal of creating a better compression ratio with the compressor
    026 * that comes next in the chain of methods.  7z will in general only
    027 * allow them to be used together with a "real" compression method but
    028 * Commons Compress doesn't enforce this.</p>
    029 *
    030 * <p>The BCJ_ filters work on executable files for the given platform
    031 * and convert relative addresses to absolute addresses in CALL
    032 * instructions.  This means they are only useful when applied to
    033 * executables of the chosen platform.</p>
    034 */
    035public enum SevenZMethod {
    036    /** no compression at all */
    037    COPY(new byte[] { (byte) 0x00 }),
    038    /** LZMA - only supported when reading */
    039    LZMA(new byte[] { (byte) 0x03, (byte) 0x01, (byte) 0x01 }),
    040    /** LZMA2 */
    041    LZMA2(new byte[] { (byte) 0x21 }),
    042    /** Deflate */
    043    DEFLATE(new byte[] { (byte) 0x04, (byte) 0x01, (byte) 0x08 }),
    044    /**
    045     * Deflate64
    046     * @since 1.16
    047     */
    048    DEFLATE64(new byte[] { (byte) 0x04, (byte) 0x01, (byte) 0x09 }),
    049    /** BZIP2 */
    050    BZIP2(new byte[] { (byte) 0x04, (byte) 0x02, (byte) 0x02 }),
    051    /**
    052     * AES encryption with a key length of 256 bit using SHA256 for
    053     * hashes - only supported when reading
    054     */
    055    AES256SHA256(new byte[] { (byte) 0x06, (byte) 0xf1, (byte) 0x07, (byte) 0x01 }),
    056    /**
    057     * BCJ x86 platform version 1.
    058     * @since 1.8
    059     */
    060    BCJ_X86_FILTER(new byte[] { 0x03, 0x03, 0x01, 0x03 }),
    061    /**
    062     * BCJ PowerPC platform.
    063     * @since 1.8
    064     */
    065    BCJ_PPC_FILTER(new byte[] { 0x03, 0x03, 0x02, 0x05 }),
    066    /**
    067     * BCJ I64 platform.
    068     * @since 1.8
    069     */
    070    BCJ_IA64_FILTER(new byte[] { 0x03, 0x03, 0x04, 0x01 }),
    071    /**
    072     * BCJ ARM platform.
    073     * @since 1.8
    074     */
    075    BCJ_ARM_FILTER(new byte[] { 0x03, 0x03, 0x05, 0x01 }),
    076    /**
    077     * BCJ ARM Thumb platform.
    078     * @since 1.8
    079     */
    080    BCJ_ARM_THUMB_FILTER(new byte[] { 0x03, 0x03, 0x07, 0x01 }),
    081    /**
    082     * BCJ Sparc platform.
    083     * @since 1.8
    084     */
    085    BCJ_SPARC_FILTER(new byte[] { 0x03, 0x03, 0x08, 0x05 }),
    086    /**
    087     * Delta filter.
    088     * @since 1.8
    089     */
    090    DELTA_FILTER(new byte[] { 0x03 });
    091
    092    static SevenZMethod byId(final byte[] id) {
    093        for (final SevenZMethod m : SevenZMethod.class.getEnumConstants()) {
    094            if (Arrays.equals(m.id, id)) {
    095                return m;
    096            }
    097        }
    098        return null;
    099    }
    100
    101    private final byte[] id;
    102
    103    SevenZMethod(final byte[] id) {
    104        this.id = id;
    105    }
    106
    107    byte[] getId() {
    108        return Arrays.copyOf(id, id.length);
    109    }
    110}