1 /*
   2  * Copyright (c) 2013, 2019, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package java.util.zip;
  27 
  28 import java.nio.ByteBuffer;
  29 import java.nio.file.attribute.FileTime;
  30 import java.time.DateTimeException;
  31 import java.time.Instant;
  32 import java.time.LocalDateTime;
  33 import java.time.ZoneId;
  34 import java.util.Date;
  35 import java.util.concurrent.TimeUnit;
  36 
  37 import static java.util.zip.ZipConstants.ENDHDR;
  38 
  39 import jdk.internal.misc.Unsafe;
  40 
  41 class ZipUtils {
  42 
  43     // used to adjust values between Windows and java epoch
  44     private static final long WINDOWS_EPOCH_IN_MICROSECONDS = -11644473600000000L;
  45 
  46     // used to indicate the corresponding windows time is not available
  47     public static final long WINDOWS_TIME_NOT_AVAILABLE = Long.MIN_VALUE;
  48 
  49     // static final ByteBuffer defaultBuf = ByteBuffer.allocateDirect(0);
  50     static final ByteBuffer defaultBuf = ByteBuffer.allocate(0);
  51 
  52     /**
  53      * Converts Windows time (in microseconds, UTC/GMT) time to FileTime.
  54      */
  55     public static final FileTime winTimeToFileTime(long wtime) {
  56         return FileTime.from(wtime / 10 + WINDOWS_EPOCH_IN_MICROSECONDS,
  57                              TimeUnit.MICROSECONDS);
  58     }
  59 
  60     /**
  61      * Converts FileTime to Windows time.
  62      */
  63     public static final long fileTimeToWinTime(FileTime ftime) {
  64         return (ftime.to(TimeUnit.MICROSECONDS) - WINDOWS_EPOCH_IN_MICROSECONDS) * 10;
  65     }
  66 
  67     /**
  68      * The upper bound of the 32-bit unix time, the "year 2038 problem".
  69      */
  70     public static final long UPPER_UNIXTIME_BOUND = 0x7fffffff;
  71 
  72     /**
  73      * Converts "standard Unix time"(in seconds, UTC/GMT) to FileTime
  74      */
  75     public static final FileTime unixTimeToFileTime(long utime) {
  76         return FileTime.from(utime, TimeUnit.SECONDS);
  77     }
  78 
  79     /**
  80      * Converts FileTime to "standard Unix time".
  81      */
  82     public static final long fileTimeToUnixTime(FileTime ftime) {
  83         return ftime.to(TimeUnit.SECONDS);
  84     }
  85 
  86     /**
  87      * Converts DOS time to Java time (number of milliseconds since epoch).
  88      */
  89     public static long dosToJavaTime(long dtime) {
  90         int year = (int) (((dtime >> 25) & 0x7f) + 1980);
  91         int month = (int) ((dtime >> 21) & 0x0f);
  92         int day = (int) ((dtime >> 16) & 0x1f);
  93         int hour = (int) ((dtime >> 11) & 0x1f);
  94         int minute = (int) ((dtime >> 5) & 0x3f);
  95         int second = (int) ((dtime << 1) & 0x3e);
  96 
  97         if (month > 0 && month < 13 && day > 0 && hour < 24 && minute < 60 && second < 60) {
  98             try {
  99                 LocalDateTime ldt = LocalDateTime.of(year, month, day, hour, minute, second);
 100                 return TimeUnit.MILLISECONDS.convert(ldt.toEpochSecond(
 101                         ZoneId.systemDefault().getRules().getOffset(ldt)), TimeUnit.SECONDS);
 102             } catch (DateTimeException dte) {
 103                 // ignore
 104             }
 105         }
 106         return overflowDosToJavaTime(year, month, day, hour, minute, second);
 107     }
 108 
 109     /*
 110      * Deal with corner cases where an arguably mal-formed DOS time is used
 111      */
 112     @SuppressWarnings("deprecation") // Use of Date constructor
 113     private static long overflowDosToJavaTime(int year, int month, int day,
 114                                               int hour, int minute, int second) {
 115         return new Date(year - 1900, month - 1, day, hour, minute, second).getTime();
 116     }
 117 
 118 
 119     /**
 120      * Converts extended DOS time to Java time, where up to 1999 milliseconds
 121      * might be encoded into the upper half of the returned long.
 122      *
 123      * @param xdostime the extended DOS time value
 124      * @return milliseconds since epoch
 125      */
 126     public static long extendedDosToJavaTime(long xdostime) {
 127         long time = dosToJavaTime(xdostime);
 128         return time + (xdostime >> 32);
 129     }
 130 
 131     /**
 132      * Converts Java time to DOS time.
 133      */
 134     private static long javaToDosTime(long time) {
 135         Instant instant = Instant.ofEpochMilli(time);
 136         LocalDateTime ldt = LocalDateTime.ofInstant(
 137                 instant, ZoneId.systemDefault());
 138         int year = ldt.getYear() - 1980;
 139         if (year < 0) {
 140             return (1 << 21) | (1 << 16);
 141         }
 142         return (year << 25 |
 143             ldt.getMonthValue() << 21 |
 144             ldt.getDayOfMonth() << 16 |
 145             ldt.getHour() << 11 |
 146             ldt.getMinute() << 5 |
 147             ldt.getSecond() >> 1) & 0xffffffffL;
 148     }
 149 
 150     /**
 151      * Converts Java time to DOS time, encoding any milliseconds lost
 152      * in the conversion into the upper half of the returned long.
 153      *
 154      * @param time milliseconds since epoch
 155      * @return DOS time with 2s remainder encoded into upper half
 156      */
 157     public static long javaToExtendedDosTime(long time) {
 158         if (time < 0) {
 159             return ZipEntry.DOSTIME_BEFORE_1980;
 160         }
 161         long dostime = javaToDosTime(time);
 162         return (dostime != ZipEntry.DOSTIME_BEFORE_1980)
 163                 ? dostime + ((time % 2000) << 32)
 164                 : ZipEntry.DOSTIME_BEFORE_1980;
 165     }
 166 
 167     /**
 168      * Fetches unsigned 16-bit value from byte array at specified offset.
 169      * The bytes are assumed to be in Intel (little-endian) byte order.
 170      */
 171     public static final int get16(byte b[], int off) {
 172         return (b[off] & 0xff) | ((b[off + 1] & 0xff) << 8);
 173     }
 174 
 175     /**
 176      * Fetches unsigned 32-bit value from byte array at specified offset.
 177      * The bytes are assumed to be in Intel (little-endian) byte order.
 178      */
 179     public static final long get32(byte b[], int off) {
 180         return (get16(b, off) | ((long)get16(b, off+2) << 16)) & 0xffffffffL;
 181     }
 182 
 183     /**
 184      * Fetches signed 64-bit value from byte array at specified offset.
 185      * The bytes are assumed to be in Intel (little-endian) byte order.
 186      */
 187     public static final long get64(byte b[], int off) {
 188         return get32(b, off) | (get32(b, off+4) << 32);
 189     }
 190 
 191     /**
 192      * Fetches signed 32-bit value from byte array at specified offset.
 193      * The bytes are assumed to be in Intel (little-endian) byte order.
 194      *
 195      */
 196     public static final int get32S(byte b[], int off) {
 197         return (get16(b, off) | (get16(b, off+2) << 16));
 198     }
 199 
 200     // fields access methods
 201     static final int CH(byte[] b, int n) {
 202         return b[n] & 0xff ;
 203     }
 204 
 205     static final int SH(byte[] b, int n) {
 206         return (b[n] & 0xff) | ((b[n + 1] & 0xff) << 8);
 207     }
 208 
 209     static final long LG(byte[] b, int n) {
 210         return ((SH(b, n)) | (SH(b, n + 2) << 16)) & 0xffffffffL;
 211     }
 212 
 213     static final long LL(byte[] b, int n) {
 214         return (LG(b, n)) | (LG(b, n + 4) << 32);
 215     }
 216 
 217     static final long GETSIG(byte[] b) {
 218         return LG(b, 0);
 219     }
 220 
 221     // local file (LOC) header fields
 222     static final long LOCSIG(byte[] b) { return LG(b, 0); } // signature
 223     static final int  LOCVER(byte[] b) { return SH(b, 4); } // version needed to extract
 224     static final int  LOCFLG(byte[] b) { return SH(b, 6); } // general purpose bit flags
 225     static final int  LOCHOW(byte[] b) { return SH(b, 8); } // compression method
 226     static final long LOCTIM(byte[] b) { return LG(b, 10);} // modification time
 227     static final long LOCCRC(byte[] b) { return LG(b, 14);} // crc of uncompressed data
 228     static final long LOCSIZ(byte[] b) { return LG(b, 18);} // compressed data size
 229     static final long LOCLEN(byte[] b) { return LG(b, 22);} // uncompressed data size
 230     static final int  LOCNAM(byte[] b) { return SH(b, 26);} // filename length
 231     static final int  LOCEXT(byte[] b) { return SH(b, 28);} // extra field length
 232 
 233     // extra local (EXT) header fields
 234     static final long EXTCRC(byte[] b) { return LG(b, 4);}  // crc of uncompressed data
 235     static final long EXTSIZ(byte[] b) { return LG(b, 8);}  // compressed size
 236     static final long EXTLEN(byte[] b) { return LG(b, 12);} // uncompressed size
 237 
 238     // end of central directory header (END) fields
 239     static final int  ENDSUB(byte[] b) { return SH(b, 8); }  // number of entries on this disk
 240     static final int  ENDTOT(byte[] b) { return SH(b, 10);}  // total number of entries
 241     static final long ENDSIZ(byte[] b) { return LG(b, 12);}  // central directory size
 242     static final long ENDOFF(byte[] b) { return LG(b, 16);}  // central directory offset
 243     static final int  ENDCOM(byte[] b) { return SH(b, 20);}  // size of zip file comment
 244     static final int  ENDCOM(byte[] b, int off) { return SH(b, off + 20);}
 245 
 246     // zip64 end of central directory recoder fields
 247     static final long ZIP64_ENDTOD(byte[] b) { return LL(b, 24);}  // total number of entries on disk
 248     static final long ZIP64_ENDTOT(byte[] b) { return LL(b, 32);}  // total number of entries
 249     static final long ZIP64_ENDSIZ(byte[] b) { return LL(b, 40);}  // central directory size
 250     static final long ZIP64_ENDOFF(byte[] b) { return LL(b, 48);}  // central directory offset
 251     static final long ZIP64_LOCOFF(byte[] b) { return LL(b, 8);}   // zip64 end offset
 252 
 253     // central directory header (CEN) fields
 254     static final long CENSIG(byte[] b, int pos) { return LG(b, pos + 0); }
 255     static final int  CENVEM(byte[] b, int pos) { return SH(b, pos + 4); }
 256     static final int  CENVER(byte[] b, int pos) { return SH(b, pos + 6); }
 257     static final int  CENFLG(byte[] b, int pos) { return SH(b, pos + 8); }
 258     static final int  CENHOW(byte[] b, int pos) { return SH(b, pos + 10);}
 259     static final long CENTIM(byte[] b, int pos) { return LG(b, pos + 12);}
 260     static final long CENCRC(byte[] b, int pos) { return LG(b, pos + 16);}
 261     static final long CENSIZ(byte[] b, int pos) { return LG(b, pos + 20);}
 262     static final long CENLEN(byte[] b, int pos) { return LG(b, pos + 24);}
 263     static final int  CENNAM(byte[] b, int pos) { return SH(b, pos + 28);}
 264     static final int  CENEXT(byte[] b, int pos) { return SH(b, pos + 30);}
 265     static final int  CENCOM(byte[] b, int pos) { return SH(b, pos + 32);}
 266     static final int  CENDSK(byte[] b, int pos) { return SH(b, pos + 34);}
 267     static final int  CENATT(byte[] b, int pos) { return SH(b, pos + 36);}
 268     static final long CENATX(byte[] b, int pos) { return LG(b, pos + 38);}
 269     static final long CENOFF(byte[] b, int pos) { return LG(b, pos + 42);}
 270 
 271     // The END header is followed by a variable length comment of size < 64k.
 272     static final long END_MAXLEN = 0xFFFF + ENDHDR;
 273     static final int READBLOCKSZ = 128;
 274 
 275     /**
 276      * Loads zip native library, if not already laoded
 277      */
 278     static void loadLibrary() {
 279         jdk.internal.access.SharedSecrets.getJavaLangAccess().loadLibrary("zip");
 280     }
 281 
 282     private static final Unsafe unsafe = Unsafe.getUnsafe();
 283 
 284     private static final long byteBufferArrayOffset = unsafe.objectFieldOffset(ByteBuffer.class, "hb");
 285     private static final long byteBufferOffsetOffset = unsafe.objectFieldOffset(ByteBuffer.class, "offset");
 286 
 287     static byte[] getBufferArray(ByteBuffer byteBuffer) {
 288         return (byte[]) unsafe.getReference(byteBuffer, byteBufferArrayOffset);
 289     }
 290 
 291     static int getBufferOffset(ByteBuffer byteBuffer) {
 292         return unsafe.getInt(byteBuffer, byteBufferOffsetOffset);
 293     }
 294 }