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 import java.io.IOException; 021 import java.util.Calendar; 022 import java.util.Date; 023 import java.util.zip.CRC32; 024 025 /** 026 * Utility class for handling DOS and Java time conversions. 027 * @Immutable 028 */ 029 public abstract class ZipUtil { 030 /** 031 * Smallest date/time ZIP can handle. 032 */ 033 private static final byte[] DOS_TIME_MIN = ZipLong.getBytes(0x00002100L); 034 035 /** 036 * Convert a Date object to a DOS date/time field. 037 * @param time the <code>Date</code> to convert 038 * @return the date as a <code>ZipLong</code> 039 */ 040 public static ZipLong toDosTime(Date time) { 041 return new ZipLong(toDosTime(time.getTime())); 042 } 043 044 /** 045 * Convert a Date object to a DOS date/time field. 046 * 047 * <p>Stolen from InfoZip's <code>fileio.c</code></p> 048 * @param t number of milliseconds since the epoch 049 * @return the date as a byte array 050 */ 051 public static byte[] toDosTime(long t) { 052 Calendar c = Calendar.getInstance(); 053 c.setTimeInMillis(t); 054 055 int year = c.get(Calendar.YEAR); 056 if (year < 1980) { 057 return copy(DOS_TIME_MIN); // stop callers from changing the array 058 } 059 int month = c.get(Calendar.MONTH) + 1; 060 long value = ((year - 1980) << 25) 061 | (month << 21) 062 | (c.get(Calendar.DAY_OF_MONTH) << 16) 063 | (c.get(Calendar.HOUR_OF_DAY) << 11) 064 | (c.get(Calendar.MINUTE) << 5) 065 | (c.get(Calendar.SECOND) >> 1); 066 return ZipLong.getBytes(value); 067 } 068 069 /** 070 * Assumes a negative integer really is a positive integer that 071 * has wrapped around and re-creates the original value. 072 * 073 * <p>This methods is no longer used as of Apache Commons Compress 074 * 1.3</p> 075 * 076 * @param i the value to treat as unsigned int. 077 * @return the unsigned int as a long. 078 */ 079 public static long adjustToLong(int i) { 080 if (i < 0) { 081 return 2 * ((long) Integer.MAX_VALUE) + 2 + i; 082 } else { 083 return i; 084 } 085 } 086 087 /** 088 * Convert a DOS date/time field to a Date object. 089 * 090 * @param zipDosTime contains the stored DOS time. 091 * @return a Date instance corresponding to the given time. 092 */ 093 public static Date fromDosTime(ZipLong zipDosTime) { 094 long dosTime = zipDosTime.getValue(); 095 return new Date(dosToJavaTime(dosTime)); 096 } 097 098 /** 099 * Converts DOS time to Java time (number of milliseconds since 100 * epoch). 101 */ 102 public static long dosToJavaTime(long dosTime) { 103 Calendar cal = Calendar.getInstance(); 104 // CheckStyle:MagicNumberCheck OFF - no point 105 cal.set(Calendar.YEAR, (int) ((dosTime >> 25) & 0x7f) + 1980); 106 cal.set(Calendar.MONTH, (int) ((dosTime >> 21) & 0x0f) - 1); 107 cal.set(Calendar.DATE, (int) (dosTime >> 16) & 0x1f); 108 cal.set(Calendar.HOUR_OF_DAY, (int) (dosTime >> 11) & 0x1f); 109 cal.set(Calendar.MINUTE, (int) (dosTime >> 5) & 0x3f); 110 cal.set(Calendar.SECOND, (int) (dosTime << 1) & 0x3e); 111 // CheckStyle:MagicNumberCheck ON 112 return cal.getTime().getTime(); 113 } 114 115 /** 116 * If the entry has Unicode*ExtraFields and the CRCs of the 117 * names/comments match those of the extra fields, transfer the 118 * known Unicode values from the extra field. 119 */ 120 static void setNameAndCommentFromExtraFields(ZipArchiveEntry ze, 121 byte[] originalNameBytes, 122 byte[] commentBytes) { 123 UnicodePathExtraField name = (UnicodePathExtraField) 124 ze.getExtraField(UnicodePathExtraField.UPATH_ID); 125 String originalName = ze.getName(); 126 String newName = getUnicodeStringIfOriginalMatches(name, 127 originalNameBytes); 128 if (newName != null && !originalName.equals(newName)) { 129 ze.setName(newName); 130 } 131 132 if (commentBytes != null && commentBytes.length > 0) { 133 UnicodeCommentExtraField cmt = (UnicodeCommentExtraField) 134 ze.getExtraField(UnicodeCommentExtraField.UCOM_ID); 135 String newComment = 136 getUnicodeStringIfOriginalMatches(cmt, commentBytes); 137 if (newComment != null) { 138 ze.setComment(newComment); 139 } 140 } 141 } 142 143 /** 144 * If the stored CRC matches the one of the given name, return the 145 * Unicode name of the given field. 146 * 147 * <p>If the field is null or the CRCs don't match, return null 148 * instead.</p> 149 */ 150 private static 151 String getUnicodeStringIfOriginalMatches(AbstractUnicodeExtraField f, 152 byte[] orig) { 153 if (f != null) { 154 CRC32 crc32 = new CRC32(); 155 crc32.update(orig); 156 long origCRC32 = crc32.getValue(); 157 158 if (origCRC32 == f.getNameCRC32()) { 159 try { 160 return ZipEncodingHelper 161 .UTF8_ZIP_ENCODING.decode(f.getUnicodeName()); 162 } catch (IOException ex) { 163 // UTF-8 unsupported? should be impossible the 164 // Unicode*ExtraField must contain some bad bytes 165 166 // TODO log this anywhere? 167 return null; 168 } 169 } 170 } 171 return null; 172 } 173 174 /** 175 * Create a copy of the given array - or return null if the 176 * argument is null. 177 */ 178 static byte[] copy(byte[] from) { 179 if (from != null) { 180 byte[] to = new byte[from.length]; 181 System.arraycopy(from, 0, to, 0, to.length); 182 return to; 183 } 184 return null; 185 } 186 187 /** 188 * Whether this library is able to read or write the given entry. 189 */ 190 static boolean canHandleEntryData(ZipArchiveEntry entry) { 191 return supportsEncryptionOf(entry) && supportsMethodOf(entry); 192 } 193 194 /** 195 * Whether this library supports the encryption used by the given 196 * entry. 197 * 198 * @return true if the entry isn't encrypted at all 199 */ 200 private static boolean supportsEncryptionOf(ZipArchiveEntry entry) { 201 return !entry.getGeneralPurposeBit().usesEncryption(); 202 } 203 204 /** 205 * Whether this library supports the compression method used by 206 * the given entry. 207 * 208 * @return true if the compression method is STORED or DEFLATED 209 */ 210 private static boolean supportsMethodOf(ZipArchiveEntry entry) { 211 return entry.getMethod() == ZipArchiveEntry.STORED 212 || entry.getMethod() == ZipArchiveEntry.DEFLATED; 213 } 214 215 /** 216 * Checks whether the entry requires features not (yet) supported 217 * by the library and throws an exception if it does. 218 */ 219 static void checkRequestedFeatures(ZipArchiveEntry ze) 220 throws UnsupportedZipFeatureException { 221 if (!supportsEncryptionOf(ze)) { 222 throw 223 new UnsupportedZipFeatureException(UnsupportedZipFeatureException 224 .Feature.ENCRYPTION, ze); 225 } 226 if (!supportsMethodOf(ze)) { 227 throw 228 new UnsupportedZipFeatureException(UnsupportedZipFeatureException 229 .Feature.METHOD, ze); 230 } 231 } 232 }