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Apache Commons Compress software defines an API for working with
compression and archive formats. These include: bzip2, gzip, pack200,
lzma, xz, Snappy, traditional Unix Compress, DEFLATE, DEFLATE64, LZ4,
Brotli, Zstandard and ar, cpio, jar, tar, zip, dump, 7z, arj.
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package org.apache.commons.compress.archivers.zip;
import java.io.IOException;
import java.math.BigInteger;
import java.time.Instant;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.util.Arrays;
import java.util.Calendar;
import java.util.Date;
import java.util.zip.CRC32;
import java.util.zip.ZipEntry;
/**
* Utility class for handling DOS and Java time conversions.
* @Immutable
*/
public abstract class ZipUtil {
/**
* DOS time constant for representing timestamps before 1980.
* Smallest date/time ZIP can handle.
*
* MS-DOS records file dates and times as packed 16-bit values. An MS-DOS date has the following format.
*
*
* Bits Contents
*
*
* - 0-4: Day of the month (1-31).
* - 5-8: Month (1 = January, 2 = February, and so on).
* - 9-15: Year offset from 1980 (add 1980 to get the actual year).
*
*
* An MS-DOS time has the following format.
*
* Bits Contents
*
*
* - 0-4: Second divided by 2.
* - 5-10: Minute (0-59).
* - 11-15: Hour (0-23 on a 24-hour clock).
*
*
* This constant expresses the minimum DOS date of January 1st 1980 at 00:00:00 or, bit-by-bit:
*
* - Year: 0000000
* - Month: 0001
* - Day: 00001
* - Hour: 00000
* - Minute: 000000
* - Seconds: 00000
*
*
*
* This was copied from {@link ZipEntry}.
*
*
* @since 1.23
*/
private static final long DOSTIME_BEFORE_1980 = (1 << 21) | (1 << 16); // 0x210000
/**
* Approximately 128 years, in milliseconds (ignoring leap years, etc.).
*
*
* This establish an approximate high-bound value for DOS times in
* milliseconds since epoch, used to enable an efficient but
* sufficient bounds check to avoid generating extended last modified
* time entries.
*
*
* Calculating the exact number is locale dependent, would require loading
* TimeZone data eagerly, and would make little practical sense. Since DOS
* times theoretically go to 2107 - with compatibility not guaranteed
* after 2099 - setting this to a time that is before but near 2099
* should be sufficient.
*
*
*
* This was copied from {@link ZipEntry}.
*
*
* @since 1.23
*/
private static final long UPPER_DOSTIME_BOUND = 128L * 365 * 24 * 60 * 60 * 1000;
/**
* Assumes a negative integer really is a positive integer that
* has wrapped around and re-creates the original value.
*
* @param i the value to treat as unsigned int.
* @return the unsigned int as a long.
*/
public static long adjustToLong(final int i) {
if (i < 0) {
return 2 * ((long) Integer.MAX_VALUE) + 2 + i;
}
return i;
}
/**
* Converts a BigInteger into a long, and blows up
* (NumberFormatException) if the BigInteger is too big.
*
* @param big BigInteger to convert.
* @return long representation of the BigInteger.
*/
static long bigToLong(final BigInteger big) {
if (big.bitLength() <= 63) { // bitLength() doesn't count the sign bit.
return big.longValue();
}
throw new NumberFormatException("The BigInteger cannot fit inside a 64 bit java long: [" + big + "]");
}
/**
* Tests if this library is able to read or write the given entry.
*/
static boolean canHandleEntryData(final ZipArchiveEntry entry) {
return supportsEncryptionOf(entry) && supportsMethodOf(entry);
}
/**
* Checks whether the entry requires features not (yet) supported
* by the library and throws an exception if it does.
*/
static void checkRequestedFeatures(final ZipArchiveEntry ze)
throws UnsupportedZipFeatureException {
if (!supportsEncryptionOf(ze)) {
throw
new UnsupportedZipFeatureException(UnsupportedZipFeatureException
.Feature.ENCRYPTION, ze);
}
if (!supportsMethodOf(ze)) {
final ZipMethod m = ZipMethod.getMethodByCode(ze.getMethod());
if (m == null) {
throw
new UnsupportedZipFeatureException(UnsupportedZipFeatureException
.Feature.METHOD, ze);
}
throw new UnsupportedZipFeatureException(m, ze);
}
}
/**
* Creates a copy of the given array - or return null if the
* argument is null.
*/
static byte[] copy(final byte[] from) {
if (from != null) {
return Arrays.copyOf(from, from.length);
}
return null;
}
static void copy(final byte[] from, final byte[] to, final int offset) {
if (from != null) {
System.arraycopy(from, 0, to, offset, from.length);
}
}
private static Date dosToJavaDate(final long dosTime) {
final Calendar cal = Calendar.getInstance();
// CheckStyle:MagicNumberCheck OFF - no point
cal.set(Calendar.YEAR, (int) ((dosTime >> 25) & 0x7f) + 1980);
cal.set(Calendar.MONTH, (int) ((dosTime >> 21) & 0x0f) - 1);
cal.set(Calendar.DATE, (int) (dosTime >> 16) & 0x1f);
cal.set(Calendar.HOUR_OF_DAY, (int) (dosTime >> 11) & 0x1f);
cal.set(Calendar.MINUTE, (int) (dosTime >> 5) & 0x3f);
cal.set(Calendar.SECOND, (int) (dosTime << 1) & 0x3e);
cal.set(Calendar.MILLISECOND, 0);
// CheckStyle:MagicNumberCheck ON
return cal.getTime();
}
/**
* Converts DOS time to Java time (number of milliseconds since
* epoch).
* @param dosTime time to convert
* @return converted time
*/
public static long dosToJavaTime(final long dosTime) {
return dosToJavaDate(dosTime).getTime();
}
/**
* Converts a DOS date/time field to a Date object.
*
* @param zipDosTime contains the stored DOS time.
* @return a Date instance corresponding to the given time.
*/
public static Date fromDosTime(final ZipLong zipDosTime) {
final long dosTime = zipDosTime.getValue();
return dosToJavaDate(dosTime);
}
/**
* If the stored CRC matches the one of the given name, return the
* Unicode name of the given field.
*
* If the field is null or the CRCs don't match, return null
* instead.
*/
private static
String getUnicodeStringIfOriginalMatches(final AbstractUnicodeExtraField f,
final byte[] orig) {
if (f != null) {
final CRC32 crc32 = new CRC32();
crc32.update(orig);
final long origCRC32 = crc32.getValue();
if (origCRC32 == f.getNameCRC32()) {
try {
return ZipEncodingHelper
.UTF8_ZIP_ENCODING.decode(f.getUnicodeName());
} catch (final IOException ex) {
// UTF-8 unsupported? should be impossible the
// Unicode*ExtraField must contain some bad bytes
}
}
}
// TODO log this anywhere?
return null;
}
/**
* Tests whether a given time (in milliseconds since Epoch) can be safely represented as DOS time
*
* @param time time in milliseconds since epoch
* @return true if the time can be safely represented as DOS time, false otherwise
* @since 1.23
*/
public static boolean isDosTime(final long time) {
return time <= UPPER_DOSTIME_BOUND && javaToDosTime(time) != DOSTIME_BEFORE_1980;
}
private static LocalDateTime javaEpochToLocalDateTime(final long time) {
final Instant instant = Instant.ofEpochMilli(time);
return LocalDateTime.ofInstant(instant, ZoneId.systemDefault());
}
// version with integer overflow fixed - see https://bugs.openjdk.org/browse/JDK-8130914
private static long javaToDosTime(final long t) {
final LocalDateTime ldt = javaEpochToLocalDateTime(t);
if (ldt.getYear() < 1980) {
return DOSTIME_BEFORE_1980;
}
return ((ldt.getYear() - 1980) << 25
| ldt.getMonthValue() << 21
| ldt.getDayOfMonth() << 16
| ldt.getHour() << 11
| ldt.getMinute() << 5
| ldt.getSecond() >> 1) & 0xffffffffL;
}
/**
*
* Converts a long into a BigInteger. Negative numbers between -1 and
* -2^31 are treated as unsigned 32 bit (e.g., positive) integers.
* Negative numbers below -2^31 cause an IllegalArgumentException
* to be thrown.
*
*
* @param l long to convert to BigInteger.
* @return BigInteger representation of the provided long.
*/
static BigInteger longToBig(long l) {
if (l < Integer.MIN_VALUE) {
throw new IllegalArgumentException("Negative longs < -2^31 not permitted: [" + l + "]");
}
if (l < 0 && l >= Integer.MIN_VALUE) {
// If someone passes in a -2, they probably mean 4294967294
// (For example, Unix UID/GID's are 32 bit unsigned.)
l = ZipUtil.adjustToLong((int) l);
}
return BigInteger.valueOf(l);
}
/**
* Reverses a byte[] array. Reverses in-place (thus provided array is
* mutated), but also returns same for convenience.
*
* @param array to reverse (mutated in-place, but also returned for
* convenience).
*
* @return the reversed array (mutated in-place, but also returned for
* convenience).
* @since 1.5
*/
public static byte[] reverse(final byte[] array) {
final int z = array.length - 1; // position of last element
for (int i = 0; i < array.length / 2; i++) {
final byte x = array[i];
array[i] = array[z - i];
array[z - i] = x;
}
return array;
}
/**
* If the entry has Unicode*ExtraFields and the CRCs of the
* names/comments match those of the extra fields, transfer the
* known Unicode values from the extra field.
*/
static void setNameAndCommentFromExtraFields(final ZipArchiveEntry ze,
final byte[] originalNameBytes,
final byte[] commentBytes) {
final ZipExtraField nameCandidate = ze.getExtraField(UnicodePathExtraField.UPATH_ID);
final UnicodePathExtraField name = nameCandidate instanceof UnicodePathExtraField
? (UnicodePathExtraField) nameCandidate : null;
final String newName = getUnicodeStringIfOriginalMatches(name,
originalNameBytes);
if (newName != null) {
ze.setName(newName);
ze.setNameSource(ZipArchiveEntry.NameSource.UNICODE_EXTRA_FIELD);
}
if (commentBytes != null && commentBytes.length > 0) {
final ZipExtraField cmtCandidate = ze.getExtraField(UnicodeCommentExtraField.UCOM_ID);
final UnicodeCommentExtraField cmt = cmtCandidate instanceof UnicodeCommentExtraField
? (UnicodeCommentExtraField) cmtCandidate : null;
final String newComment =
getUnicodeStringIfOriginalMatches(cmt, commentBytes);
if (newComment != null) {
ze.setComment(newComment);
ze.setCommentSource(ZipArchiveEntry.CommentSource.UNICODE_EXTRA_FIELD);
}
}
}
/**
* Converts a signed byte into an unsigned integer representation
* (e.g., -1 becomes 255).
*
* @param b byte to convert to int
* @return int representation of the provided byte
* @since 1.5
*/
public static int signedByteToUnsignedInt(final byte b) {
if (b >= 0) {
return b;
}
return 256 + b;
}
/**
* Tests if this library supports the encryption used by the given
* entry.
*
* @return true if the entry isn't encrypted at all
*/
private static boolean supportsEncryptionOf(final ZipArchiveEntry entry) {
return !entry.getGeneralPurposeBit().usesEncryption();
}
/**
* Tests if this library supports the compression method used by
* the given entry.
*
* @return true if the compression method is supported
*/
private static boolean supportsMethodOf(final ZipArchiveEntry entry) {
return entry.getMethod() == ZipEntry.STORED
|| entry.getMethod() == ZipMethod.UNSHRINKING.getCode()
|| entry.getMethod() == ZipMethod.IMPLODING.getCode()
|| entry.getMethod() == ZipEntry.DEFLATED
|| entry.getMethod() == ZipMethod.ENHANCED_DEFLATED.getCode()
|| entry.getMethod() == ZipMethod.BZIP2.getCode();
}
/**
* Converts a Date object to a DOS date/time field.
*
* @param time the {@code Date} to convert
* @return the date as a {@code ZipLong}
*/
public static ZipLong toDosTime(final Date time) {
return new ZipLong(toDosTime(time.getTime()));
}
/**
* Converts a Date object to a DOS date/time field.
*
* Stolen from InfoZip's {@code fileio.c}
* @param t number of milliseconds since the epoch
* @return the date as a byte array
*/
public static byte[] toDosTime(final long t) {
final byte[] result = new byte[4];
toDosTime(t, result, 0);
return result;
}
/**
* Converts a Date object to a DOS date/time field.
*
* Stolen from InfoZip's {@code fileio.c}
* @param t number of milliseconds since the epoch
* @param buf the output buffer
* @param offset
* The offset within the output buffer of the first byte to be written.
* must be non-negative and no larger than {@code buf.length-4}
*/
public static void toDosTime(final long t, final byte[] buf, final int offset) {
ZipLong.putLong(javaToDosTime(t), buf, offset);
}
/**
* Converts an unsigned integer to a signed byte (e.g., 255 becomes -1).
*
* @param i integer to convert to byte
* @return byte representation of the provided int
* @throws IllegalArgumentException if the provided integer is not inside the range [0,255].
* @since 1.5
*/
public static byte unsignedIntToSignedByte(final int i) {
if (i > 255 || i < 0) {
throw new IllegalArgumentException("Can only convert non-negative integers between [0,255] to byte: [" + i + "]");
}
if (i < 128) {
return (byte) i;
}
return (byte) (i - 256);
}
}