Back to index...

	/*
	* Copyright (c) 2013, 2018, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package java.util.zip;

	import java.nio.Buffer;
	import java.nio.ByteBuffer;
	import java.nio.file.attribute.FileTime;
	import java.security.AccessController;
	import java.security.PrivilegedAction;
	import java.time.DateTimeException;
	import java.time.Instant;
	import java.time.LocalDateTime;
	import java.time.ZoneId;
	import java.util.Date;
	import java.util.concurrent.TimeUnit;

	import static java.util.zip.ZipConstants.ENDHDR;

	import jdk.internal.misc.Unsafe;
	import sun.nio.ch.DirectBuffer;

	class ZipUtils {

	// used to adjust values between Windows and java epoch
	private static final long WINDOWS_EPOCH_IN_MICROSECONDS = -11644473600000000L;

	// used to indicate the corresponding windows time is not available
	public static final long WINDOWS_TIME_NOT_AVAILABLE = Long.MIN_VALUE;

	// static final ByteBuffer defaultBuf = ByteBuffer.allocateDirect(0);
	static final ByteBuffer defaultBuf = ByteBuffer.allocate(0);

	/**
	* Converts Windows time (in microseconds, UTC/GMT) time to FileTime.
	*/
	public static final FileTime winTimeToFileTime(long wtime) {
	return FileTime.from(wtime / 10 + WINDOWS_EPOCH_IN_MICROSECONDS,
	TimeUnit.MICROSECONDS);
	}

	/**
	* Converts FileTime to Windows time.
	*/
	public static final long fileTimeToWinTime(FileTime ftime) {
	return (ftime.to(TimeUnit.MICROSECONDS) - WINDOWS_EPOCH_IN_MICROSECONDS) * 10;
	}

	/**
	* The upper bound of the 32-bit unix time, the "year 2038 problem".
	*/
	public static final long UPPER_UNIXTIME_BOUND = 0x7fffffff;

	/**
	* Converts "standard Unix time"(in seconds, UTC/GMT) to FileTime
	*/
	public static final FileTime unixTimeToFileTime(long utime) {
	return FileTime.from(utime, TimeUnit.SECONDS);
	}

	/**
	* Converts FileTime to "standard Unix time".
	*/
	public static final long fileTimeToUnixTime(FileTime ftime) {
	return ftime.to(TimeUnit.SECONDS);
	}

	/**
	* Converts DOS time to Java time (number of milliseconds since epoch).
	*/
	public static long dosToJavaTime(long dtime) {
	int year = (int) (((dtime >> 25) & 0x7f) + 1980);
	int month = (int) ((dtime >> 21) & 0x0f);
	int day = (int) ((dtime >> 16) & 0x1f);
	int hour = (int) ((dtime >> 11) & 0x1f);
	int minute = (int) ((dtime >> 5) & 0x3f);
	int second = (int) ((dtime << 1) & 0x3e);

	if (month > 0 && month < 13 && day > 0 && hour < 24 && minute < 60 && second < 60) {
	try {
	LocalDateTime ldt = LocalDateTime.of(year, month, day, hour, minute, second);
	return TimeUnit.MILLISECONDS.convert(ldt.toEpochSecond(
	ZoneId.systemDefault().getRules().getOffset(ldt)), TimeUnit.SECONDS);
	} catch (DateTimeException dte) {
	// ignore
	}
	}
	return overflowDosToJavaTime(year, month, day, hour, minute, second);
	}

	/*
	* Deal with corner cases where an arguably mal-formed DOS time is used
	*/
	@SuppressWarnings("deprecation") // Use of Date constructor
	private static long overflowDosToJavaTime(int year, int month, int day,
	int hour, int minute, int second) {
	return new Date(year - 1900, month - 1, day, hour, minute, second).getTime();
	}


	/**
	* Converts extended DOS time to Java time, where up to 1999 milliseconds
	* might be encoded into the upper half of the returned long.
	*
	* @param xdostime the extended DOS time value
	* @return milliseconds since epoch
	*/
	public static long extendedDosToJavaTime(long xdostime) {
	long time = dosToJavaTime(xdostime);
	return time + (xdostime >> 32);
	}

	/**
	* Converts Java time to DOS time.
	*/
	private static long javaToDosTime(long time) {
	Instant instant = Instant.ofEpochMilli(time);
	LocalDateTime ldt = LocalDateTime.ofInstant(
	instant, ZoneId.systemDefault());
	int year = ldt.getYear() - 1980;
	if (year < 0) {
	return (1 << 21) \| (1 << 16);
	}
	return (year << 25 \|
	ldt.getMonthValue() << 21 \|
	ldt.getDayOfMonth() << 16 \|
	ldt.getHour() << 11 \|
	ldt.getMinute() << 5 \|
	ldt.getSecond() >> 1) & 0xffffffffL;
	}

	/**
	* Converts Java time to DOS time, encoding any milliseconds lost
	* in the conversion into the upper half of the returned long.
	*
	* @param time milliseconds since epoch
	* @return DOS time with 2s remainder encoded into upper half
	*/
	public static long javaToExtendedDosTime(long time) {
	if (time < 0) {
	return ZipEntry.DOSTIME_BEFORE_1980;
	}
	long dostime = javaToDosTime(time);
	return (dostime != ZipEntry.DOSTIME_BEFORE_1980)
	? dostime + ((time % 2000) << 32)
	: ZipEntry.DOSTIME_BEFORE_1980;
	}

	/**
	* Fetches unsigned 16-bit value from byte array at specified offset.
	* The bytes are assumed to be in Intel (little-endian) byte order.
	*/
	public static final int get16(byte b[], int off) {
	return (b[off] & 0xff) \| ((b[off + 1] & 0xff) << 8);
	}

	/**
	* Fetches unsigned 32-bit value from byte array at specified offset.
	* The bytes are assumed to be in Intel (little-endian) byte order.
	*/
	public static final long get32(byte b[], int off) {
	return (get16(b, off) \| ((long)get16(b, off+2) << 16)) & 0xffffffffL;
	}

	/**
	* Fetches signed 64-bit value from byte array at specified offset.
	* The bytes are assumed to be in Intel (little-endian) byte order.
	*/
	public static final long get64(byte b[], int off) {
	return get32(b, off) \| (get32(b, off+4) << 32);
	}

	/**
	* Fetches signed 32-bit value from byte array at specified offset.
	* The bytes are assumed to be in Intel (little-endian) byte order.
	*
	*/
	public static final int get32S(byte b[], int off) {
	return (get16(b, off) \| (get16(b, off+2) << 16));
	}

	// fields access methods
	static final int CH(byte[] b, int n) {
	return b[n] & 0xff ;
	}

	static final int SH(byte[] b, int n) {
	return (b[n] & 0xff) \| ((b[n + 1] & 0xff) << 8);
	}

	static final long LG(byte[] b, int n) {
	return ((SH(b, n)) \| (SH(b, n + 2) << 16)) & 0xffffffffL;
	}

	static final long LL(byte[] b, int n) {
	return (LG(b, n)) \| (LG(b, n + 4) << 32);
	}

	static final long GETSIG(byte[] b) {
	return LG(b, 0);
	}

	// local file (LOC) header fields
	static final long LOCSIG(byte[] b) { return LG(b, 0); } // signature
	static final int LOCVER(byte[] b) { return SH(b, 4); } // version needed to extract
	static final int LOCFLG(byte[] b) { return SH(b, 6); } // general purpose bit flags
	static final int LOCHOW(byte[] b) { return SH(b, 8); } // compression method
	static final long LOCTIM(byte[] b) { return LG(b, 10);} // modification time
	static final long LOCCRC(byte[] b) { return LG(b, 14);} // crc of uncompressed data
	static final long LOCSIZ(byte[] b) { return LG(b, 18);} // compressed data size
	static final long LOCLEN(byte[] b) { return LG(b, 22);} // uncompressed data size
	static final int LOCNAM(byte[] b) { return SH(b, 26);} // filename length
	static final int LOCEXT(byte[] b) { return SH(b, 28);} // extra field length

	// extra local (EXT) header fields
	static final long EXTCRC(byte[] b) { return LG(b, 4);} // crc of uncompressed data
	static final long EXTSIZ(byte[] b) { return LG(b, 8);} // compressed size
	static final long EXTLEN(byte[] b) { return LG(b, 12);} // uncompressed size

	// end of central directory header (END) fields
	static final int ENDSUB(byte[] b) { return SH(b, 8); } // number of entries on this disk
	static final int ENDTOT(byte[] b) { return SH(b, 10);} // total number of entries
	static final long ENDSIZ(byte[] b) { return LG(b, 12);} // central directory size
	static final long ENDOFF(byte[] b) { return LG(b, 16);} // central directory offset
	static final int ENDCOM(byte[] b) { return SH(b, 20);} // size of zip file comment
	static final int ENDCOM(byte[] b, int off) { return SH(b, off + 20);}

	// zip64 end of central directory recoder fields
	static final long ZIP64_ENDTOD(byte[] b) { return LL(b, 24);} // total number of entries on disk
	static final long ZIP64_ENDTOT(byte[] b) { return LL(b, 32);} // total number of entries
	static final long ZIP64_ENDSIZ(byte[] b) { return LL(b, 40);} // central directory size
	static final long ZIP64_ENDOFF(byte[] b) { return LL(b, 48);} // central directory offset
	static final long ZIP64_LOCOFF(byte[] b) { return LL(b, 8);} // zip64 end offset

	// central directory header (CEN) fields
	static final long CENSIG(byte[] b, int pos) { return LG(b, pos + 0); }
	static final int CENVEM(byte[] b, int pos) { return SH(b, pos + 4); }
	static final int CENVER(byte[] b, int pos) { return SH(b, pos + 6); }
	static final int CENFLG(byte[] b, int pos) { return SH(b, pos + 8); }
	static final int CENHOW(byte[] b, int pos) { return SH(b, pos + 10);}
	static final long CENTIM(byte[] b, int pos) { return LG(b, pos + 12);}
	static final long CENCRC(byte[] b, int pos) { return LG(b, pos + 16);}
	static final long CENSIZ(byte[] b, int pos) { return LG(b, pos + 20);}
	static final long CENLEN(byte[] b, int pos) { return LG(b, pos + 24);}
	static final int CENNAM(byte[] b, int pos) { return SH(b, pos + 28);}
	static final int CENEXT(byte[] b, int pos) { return SH(b, pos + 30);}
	static final int CENCOM(byte[] b, int pos) { return SH(b, pos + 32);}
	static final int CENDSK(byte[] b, int pos) { return SH(b, pos + 34);}
	static final int CENATT(byte[] b, int pos) { return SH(b, pos + 36);}
	static final long CENATX(byte[] b, int pos) { return LG(b, pos + 38);}
	static final long CENOFF(byte[] b, int pos) { return LG(b, pos + 42);}

	// The END header is followed by a variable length comment of size < 64k.
	static final long END_MAXLEN = 0xFFFF + ENDHDR;
	static final int READBLOCKSZ = 128;

	/**
	* Loads zip native library, if not already laoded
	*/
	static void loadLibrary() {
	SecurityManager sm = System.getSecurityManager();
	if (sm == null) {
	System.loadLibrary("zip");
	} else {
	PrivilegedAction<Void> pa = () -> { System.loadLibrary("zip"); return null; };
	AccessController.doPrivileged(pa);
	}
	}

	private static final Unsafe unsafe = Unsafe.getUnsafe();

	private static final long byteBufferArrayOffset = unsafe.objectFieldOffset(ByteBuffer.class, "hb");
	private static final long byteBufferOffsetOffset = unsafe.objectFieldOffset(ByteBuffer.class, "offset");

	static byte[] getBufferArray(ByteBuffer byteBuffer) {
	return (byte[]) unsafe.getObject(byteBuffer, byteBufferArrayOffset);
	}

	static int getBufferOffset(ByteBuffer byteBuffer) {
	return unsafe.getInt(byteBuffer, byteBufferOffsetOffset);
	}
	}

Back to index...