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 * 017 */ 018 package org.apache.commons.compress.archivers.zip; 019 020 /** 021 * Parser/encoder for the "general purpose bit" field in ZIP's local 022 * file and central directory headers. 023 * @since 1.1 024 * @NotThreadSafe 025 */ 026 public final class GeneralPurposeBit { 027 /** 028 * Indicates that the file is encrypted. 029 */ 030 private static final int ENCRYPTION_FLAG = 1 << 0; 031 032 /** 033 * Indicates that a data descriptor stored after the file contents 034 * will hold CRC and size information. 035 */ 036 private static final int DATA_DESCRIPTOR_FLAG = 1 << 3; 037 038 /** 039 * Indicates strong encryption. 040 */ 041 private static final int STRONG_ENCRYPTION_FLAG = 1 << 6; 042 043 /** 044 * Indicates that filenames are written in utf-8. 045 * 046 * <p>The only reason this is public is that {@link 047 * ZipArchiveOutputStream#EFS_FLAG} was public in Apache Commons 048 * Compress 1.0 and we needed a substitute for it.</p> 049 */ 050 public static final int UFT8_NAMES_FLAG = 1 << 11; 051 052 private boolean languageEncodingFlag = false; 053 private boolean dataDescriptorFlag = false; 054 private boolean encryptionFlag = false; 055 private boolean strongEncryptionFlag = false; 056 057 public GeneralPurposeBit() { 058 } 059 060 /** 061 * whether the current entry uses UTF8 for file name and comment. 062 */ 063 public boolean usesUTF8ForNames() { 064 return languageEncodingFlag; 065 } 066 067 /** 068 * whether the current entry will use UTF8 for file name and comment. 069 */ 070 public void useUTF8ForNames(boolean b) { 071 languageEncodingFlag = b; 072 } 073 074 /** 075 * whether the current entry uses the data descriptor to store CRC 076 * and size information 077 */ 078 public boolean usesDataDescriptor() { 079 return dataDescriptorFlag; 080 } 081 082 /** 083 * whether the current entry will use the data descriptor to store 084 * CRC and size information 085 */ 086 public void useDataDescriptor(boolean b) { 087 dataDescriptorFlag = b; 088 } 089 090 /** 091 * whether the current entry is encrypted 092 */ 093 public boolean usesEncryption() { 094 return encryptionFlag; 095 } 096 097 /** 098 * whether the current entry will be encrypted 099 */ 100 public void useEncryption(boolean b) { 101 encryptionFlag = b; 102 } 103 104 /** 105 * whether the current entry is encrypted using strong encryption 106 */ 107 public boolean usesStrongEncryption() { 108 return encryptionFlag && strongEncryptionFlag; 109 } 110 111 /** 112 * whether the current entry will be encrypted using strong encryption 113 */ 114 public void useStrongEncryption(boolean b) { 115 strongEncryptionFlag = b; 116 if (b) { 117 useEncryption(true); 118 } 119 } 120 121 /** 122 * Encodes the set bits in a form suitable for ZIP archives. 123 */ 124 public byte[] encode() { 125 return 126 ZipShort.getBytes((dataDescriptorFlag ? DATA_DESCRIPTOR_FLAG : 0) 127 | 128 (languageEncodingFlag ? UFT8_NAMES_FLAG : 0) 129 | 130 (encryptionFlag ? ENCRYPTION_FLAG : 0) 131 | 132 (strongEncryptionFlag ? STRONG_ENCRYPTION_FLAG : 0) 133 ); 134 } 135 136 /** 137 * Parses the supported flags from the given archive data. 138 * @param data local file header or a central directory entry. 139 * @param offset offset at which the general purpose bit starts 140 */ 141 public static GeneralPurposeBit parse(final byte[] data, final int offset) { 142 final int generalPurposeFlag = ZipShort.getValue(data, offset); 143 GeneralPurposeBit b = new GeneralPurposeBit(); 144 b.useDataDescriptor((generalPurposeFlag & DATA_DESCRIPTOR_FLAG) != 0); 145 b.useUTF8ForNames((generalPurposeFlag & UFT8_NAMES_FLAG) != 0); 146 b.useStrongEncryption((generalPurposeFlag & STRONG_ENCRYPTION_FLAG) 147 != 0); 148 b.useEncryption((generalPurposeFlag & ENCRYPTION_FLAG) != 0); 149 return b; 150 } 151 152 @Override 153 public int hashCode() { 154 return 3 * (7 * (13 * (17 * (encryptionFlag ? 1 : 0) 155 + (strongEncryptionFlag ? 1 : 0)) 156 + (languageEncodingFlag ? 1 : 0)) 157 + (dataDescriptorFlag ? 1 : 0)); 158 } 159 160 @Override 161 public boolean equals(Object o) { 162 if (!(o instanceof GeneralPurposeBit)) { 163 return false; 164 } 165 GeneralPurposeBit g = (GeneralPurposeBit) o; 166 return g.encryptionFlag == encryptionFlag 167 && g.strongEncryptionFlag == strongEncryptionFlag 168 && g.languageEncodingFlag == languageEncodingFlag 169 && g.dataDescriptorFlag == dataDescriptorFlag; 170 } 171 }