1 /*
   2  * Copyright (c) 1996, 2015, 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.io.OutputStream;
  29 import java.io.IOException;
  30 import java.nio.charset.Charset;
  31 import java.nio.charset.StandardCharsets;
  32 import java.util.Vector;
  33 import java.util.HashSet;
  34 import static java.util.zip.ZipConstants64.*;
  35 import static java.util.zip.ZipUtils.*;
  36 
  37 /**
  38  * This class implements an output stream filter for writing files in the
  39  * ZIP file format. Includes support for both compressed and uncompressed
  40  * entries.
  41  *
  42  * @author      David Connelly
  43  */
  44 public
  45 class ZipOutputStream extends DeflaterOutputStream implements ZipConstants {
  46 
  47     /**
  48      * Whether to use ZIP64 for zip files with more than 64k entries.
  49      * Until ZIP64 support in zip implementations is ubiquitous, this
  50      * system property allows the creation of zip files which can be
  51      * read by legacy zip implementations which tolerate "incorrect"
  52      * total entry count fields, such as the ones in jdk6, and even
  53      * some in jdk7.
  54      */
  55     private static final boolean inhibitZip64 =
  56         Boolean.parseBoolean(
  57             java.security.AccessController.doPrivileged(
  58                 new sun.security.action.GetPropertyAction(
  59                     "jdk.util.zip.inhibitZip64", "false")));
  60 
  61     private static class XEntry {
  62         final ZipEntry entry;
  63         final long offset;
  64         public XEntry(ZipEntry entry, long offset) {
  65             this.entry = entry;
  66             this.offset = offset;
  67         }
  68     }
  69 
  70     private XEntry current;
  71     private Vector<XEntry> xentries = new Vector<>();
  72     private HashSet<String> names = new HashSet<>();
  73     private CRC32 crc = new CRC32();
  74     private long written = 0;
  75     private long locoff = 0;
  76     private byte[] comment;
  77     private int method = DEFLATED;
  78     private boolean finished;
  79 
  80     private boolean closed = false;
  81 
  82     private final ZipCoder zc;
  83 
  84     private static int version(ZipEntry e) throws ZipException {




  85         switch (e.method) {
  86         case DEFLATED: return 20;
  87         case STORED:   return 10;
  88         default: throw new ZipException("unsupported compression method");







  89         }











  90     }
  91 
  92     /**
  93      * Checks to make sure that this stream has not been closed.
  94      */
  95     private void ensureOpen() throws IOException {
  96         if (closed) {
  97             throw new IOException("Stream closed");
  98         }
  99     }
 100     /**
 101      * Compression method for uncompressed (STORED) entries.
 102      */
 103     public static final int STORED = ZipEntry.STORED;
 104 
 105     /**
 106      * Compression method for compressed (DEFLATED) entries.
 107      */
 108     public static final int DEFLATED = ZipEntry.DEFLATED;
 109 
 110     /**
 111      * Creates a new ZIP output stream.
 112      *
 113      * <p>The UTF-8 {@link java.nio.charset.Charset charset} is used
 114      * to encode the entry names and comments.
 115      *
 116      * @param out the actual output stream
 117      */
 118     public ZipOutputStream(OutputStream out) {
 119         this(out, StandardCharsets.UTF_8);













 120     }
 121 
 122     /**
 123      * Creates a new ZIP output stream.
 124      *
 125      * @param out the actual output stream
 126      *
 127      * @param charset the {@linkplain java.nio.charset.Charset charset}
 128      *                to be used to encode the entry names and comments
 129      *
 130      * @since 1.7
 131      */
 132     public ZipOutputStream(OutputStream out, Charset charset) {















 133         super(out, new Deflater(Deflater.DEFAULT_COMPRESSION, true));
 134         if (charset == null)
 135             throw new NullPointerException("charset is null");
 136         this.zc = ZipCoder.get(charset);
 137         usesDefaultDeflater = true;


 138     }
 139 
 140     /**
 141      * Sets the ZIP file comment.
 142      * @param comment the comment string
 143      * @exception IllegalArgumentException if the length of the specified
 144      *            ZIP file comment is greater than 0xFFFF bytes
 145      */
 146     public void setComment(String comment) {
 147         if (comment != null) {
 148             this.comment = zc.getBytes(comment);
 149             if (this.comment.length > 0xffff)
 150                 throw new IllegalArgumentException("ZIP file comment too long.");
 151         }
 152     }
 153 
 154     /**
 155      * Sets the default compression method for subsequent entries. This
 156      * default will be used whenever the compression method is not specified
 157      * for an individual ZIP file entry, and is initially set to DEFLATED.
 158      * @param method the default compression method
 159      * @exception IllegalArgumentException if the specified compression method
 160      *            is invalid
 161      */
 162     public void setMethod(int method) {
 163         if (method != DEFLATED && method != STORED) {
 164             throw new IllegalArgumentException("invalid compression method");
 165         }
 166         this.method = method;
 167     }
 168 
 169     /**
 170      * Sets the compression level for subsequent entries which are DEFLATED.
 171      * The default setting is DEFAULT_COMPRESSION.
 172      * @param level the compression level (0-9)
 173      * @exception IllegalArgumentException if the compression level is invalid
 174      */
 175     public void setLevel(int level) {
 176         def.setLevel(level);
 177     }
 178 
 179     /**
 180      * Begins writing a new ZIP file entry and positions the stream to the
 181      * start of the entry data. Closes the current entry if still active.
 182      * The default compression method will be used if no compression method
 183      * was specified for the entry, and the current time will be used if
 184      * the entry has no set modification time.
 185      * @param e the ZIP entry to be written
 186      * @exception ZipException if a ZIP format error has occurred
 187      * @exception IOException if an I/O error has occurred
 188      */
 189     public void putNextEntry(ZipEntry e) throws IOException {
 190         ensureOpen();
 191         if (current != null) {
 192             closeEntry();       // close previous entry
 193         }



 194         if (e.xdostime == -1) {
 195             // by default, do NOT use extended timestamps in extra
 196             // data, for now.
 197             e.setTime(System.currentTimeMillis());
 198         }
 199         if (e.method == -1) {
 200             e.method = method;  // use default method
 201         }
 202         // store size, compressed size, and crc-32 in LOC header
 203         e.flag = 0;
 204         switch (e.method) {
 205         case DEFLATED:
 206             // store size, compressed size, and crc-32 in data descriptor
 207             // immediately following the compressed entry data
 208             if (e.size  == -1 || e.csize == -1 || e.crc   == -1)
 209                 e.flag = 8;
 210 
 211             break;
 212         case STORED:
 213             // compressed size, uncompressed size, and crc-32 must all be
 214             // set for entries using STORED compression method
 215             if (e.size == -1) {
 216                 e.size = e.csize;
 217             } else if (e.csize == -1) {
 218                 e.csize = e.size;
 219             } else if (e.size != e.csize) {
 220                 throw new ZipException(
 221                     "STORED entry where compressed != uncompressed size");
 222             }
 223             if (e.size == -1 || e.crc == -1) {
 224                 throw new ZipException(
 225                     "STORED entry missing size, compressed size, or crc-32");
 226             }



 227             break;
 228         default:
 229             throw new ZipException("unsupported compression method");
 230         }
 231         if (! names.add(e.name)) {
 232             throw new ZipException("duplicate entry: " + e.name);
 233         }
 234         if (zc.isUTF8())
 235             e.flag |= EFS;


 236         current = new XEntry(e, written);
 237         xentries.add(current);
 238         writeLOC(current);






 239     }
 240 
 241     /**
 242      * Closes the current ZIP entry and positions the stream for writing
 243      * the next entry.
 244      * @exception ZipException if a ZIP format error has occurred
 245      * @exception IOException if an I/O error has occurred
 246      */
 247     public void closeEntry() throws IOException {
 248         ensureOpen();
 249         if (current != null) {
 250             ZipEntry e = current.entry;
 251             switch (e.method) {
 252             case DEFLATED:
 253                 def.finish();
 254                 while (!def.finished()) {
 255                     deflate();
 256                 }
 257                 if ((e.flag & 8) == 0) {
 258                     // verify size, compressed size, and crc-32 settings
 259                     if (e.size != def.getBytesRead()) {
 260                         throw new ZipException(
 261                             "invalid entry size (expected " + e.size +
 262                             " but got " + def.getBytesRead() + " bytes)");
 263                     }
 264                     if (e.csize != def.getBytesWritten()) {
 265                         throw new ZipException(
 266                             "invalid entry compressed size (expected " +
 267                             e.csize + " but got " + def.getBytesWritten() + " bytes)");
 268                     }
 269                     if (e.crc != crc.getValue()) {
 270                         throw new ZipException(
 271                             "invalid entry CRC-32 (expected 0x" +
 272                             Long.toHexString(e.crc) + " but got 0x" +
 273                             Long.toHexString(crc.getValue()) + ")");
 274                     }
 275                 } else {
 276                     e.size  = def.getBytesRead();
 277                     e.csize = def.getBytesWritten();
 278                     e.crc = crc.getValue();
 279                     writeEXT(e);
 280                 }
 281                 def.reset();
 282                 written += e.csize;









 283                 break;
 284             case STORED:
 285                 // we already know that both e.size and e.csize are the same
 286                 if (e.size != written - locoff) {
 287                     throw new ZipException(
 288                         "invalid entry size (expected " + e.size +
 289                         " but got " + (written - locoff) + " bytes)");
 290                 }
 291                 if (e.crc != crc.getValue()) {
 292                     throw new ZipException(
 293                          "invalid entry crc-32 (expected 0x" +
 294                          Long.toHexString(e.crc) + " but got 0x" +
 295                          Long.toHexString(crc.getValue()) + ")");
 296                 }
 297                 break;
 298             default:
 299                 throw new ZipException("invalid compression method");
 300             }
 301             crc.reset();
 302             current = null;
 303         }
 304     }
 305 
 306     /**
 307      * Writes an array of bytes to the current ZIP entry data. This method
 308      * will block until all the bytes are written.
 309      * @param b the data to be written
 310      * @param off the start offset in the data
 311      * @param len the number of bytes that are written
 312      * @exception ZipException if a ZIP file error has occurred
 313      * @exception IOException if an I/O error has occurred
 314      */
 315     public synchronized void write(byte[] b, int off, int len)
 316         throws IOException
 317     {
 318         ensureOpen();
 319         if (off < 0 || len < 0 || off > b.length - len) {
 320             throw new IndexOutOfBoundsException();
 321         } else if (len == 0) {
 322             return;
 323         }
 324 
 325         if (current == null) {
 326             throw new ZipException("no current ZIP entry");
 327         }
 328         ZipEntry entry = current.entry;
 329         switch (entry.method) {
 330         case DEFLATED:
 331             super.write(b, off, len);

 332             break;
 333         case STORED:
 334             written += len;
 335             if (written - locoff > entry.size) {
 336                 throw new ZipException(
 337                     "attempt to write past end of STORED entry");
 338             }







 339             out.write(b, off, len);
 340             break;
 341         default:
 342             throw new ZipException("invalid compression method");
 343         }
 344         crc.update(b, off, len);
 345     }
 346 
 347     /**
 348      * Finishes writing the contents of the ZIP output stream without closing
 349      * the underlying stream. Use this method when applying multiple filters
 350      * in succession to the same output stream.
 351      * @exception ZipException if a ZIP file error has occurred
 352      * @exception IOException if an I/O exception has occurred
 353      */
 354     public void finish() throws IOException {
 355         ensureOpen();
 356         if (finished) {
 357             return;
 358         }
 359         if (current != null) {
 360             closeEntry();
 361         }
 362         // write central directory
 363         long off = written;
 364         for (XEntry xentry : xentries)
 365             writeCEN(xentry);
 366         writeEND(off, written - off);
 367         finished = true;
 368     }
 369 
 370     /**
 371      * Closes the ZIP output stream as well as the stream being filtered.
 372      * @exception ZipException if a ZIP file error has occurred
 373      * @exception IOException if an I/O error has occurred
 374      */
 375     public void close() throws IOException {
 376         if (!closed) {
 377             super.close();
 378             closed = true;
 379         }
 380     }
 381 
 382     /*
 383      * Writes local file (LOC) header for specified entry.
 384      */
 385     private void writeLOC(XEntry xentry) throws IOException {
 386         ZipEntry e = xentry.entry;
 387         int flag = e.flag;
 388         boolean hasZip64 = false;
 389         int elen = getExtraLen(e.extra);
 390 
 391         writeInt(LOCSIG);               // LOC header signature
 392         if ((flag & 8) == 8) {
 393             writeShort(version(e));     // version needed to extract
 394             writeShort(flag);           // general purpose bit flag
 395             writeShort(e.method);       // compression method
 396             writeInt(e.xdostime);       // last modification time
 397             // store size, uncompressed size, and crc-32 in data descriptor
 398             // immediately following compressed entry data
 399             writeInt(0);
 400             writeInt(0);
 401             writeInt(0);
 402         } else {
 403             if (e.csize >= ZIP64_MAGICVAL || e.size >= ZIP64_MAGICVAL) {
 404                 hasZip64 = true;
 405                 writeShort(45);         // ver 4.5 for zip64
 406             } else {
 407                 writeShort(version(e)); // version needed to extract
 408             }
 409             writeShort(flag);           // general purpose bit flag
 410             writeShort(e.method);       // compression method
 411             writeInt(e.xdostime);       // last modification time
 412             writeInt(e.crc);            // crc-32
 413             if (hasZip64) {
 414                 writeInt(ZIP64_MAGICVAL);
 415                 writeInt(ZIP64_MAGICVAL);
 416                 elen += 20;        //headid(2) + size(2) + size(8) + csize(8)
 417             } else {
 418                 writeInt(e.csize);  // compressed size
 419                 writeInt(e.size);   // uncompressed size
 420             }
 421         }
 422         byte[] nameBytes = zc.getBytes(e.name);
 423         writeShort(nameBytes.length);
 424 
 425         int elenEXTT = 0;               // info-zip extended timestamp
 426         int flagEXTT = 0;
 427         if (e.mtime != null) {
 428             elenEXTT += 4;
 429             flagEXTT |= EXTT_FLAG_LMT;
 430         }
 431         if (e.atime != null) {
 432             elenEXTT += 4;
 433             flagEXTT |= EXTT_FLAG_LAT;
 434         }
 435         if (e.ctime != null) {
 436             elenEXTT += 4;
 437             flagEXTT |= EXTT_FLAT_CT;
 438         }
 439         if (flagEXTT != 0)
 440             elen += (elenEXTT + 5);    // headid(2) + size(2) + flag(1) + data
 441         writeShort(elen);
 442         writeBytes(nameBytes, 0, nameBytes.length);
 443         if (hasZip64) {
 444             writeShort(ZIP64_EXTID);
 445             writeShort(16);
 446             writeLong(e.size);
 447             writeLong(e.csize);
 448         }
 449         if (flagEXTT != 0) {
 450             writeShort(EXTID_EXTT);
 451             writeShort(elenEXTT + 1);      // flag + data
 452             writeByte(flagEXTT);
 453             if (e.mtime != null)
 454                 writeInt(fileTimeToUnixTime(e.mtime));
 455             if (e.atime != null)
 456                 writeInt(fileTimeToUnixTime(e.atime));
 457             if (e.ctime != null)
 458                 writeInt(fileTimeToUnixTime(e.ctime));
 459         }
 460         writeExtra(e.extra);
 461         locoff = written;
 462     }
 463 
 464     /*
 465      * Writes extra data descriptor (EXT) for specified entry.
 466      */
 467     private void writeEXT(ZipEntry e) throws IOException {
 468         writeInt(EXTSIG);           // EXT header signature
 469         writeInt(e.crc);            // crc-32





 470         if (e.csize >= ZIP64_MAGICVAL || e.size >= ZIP64_MAGICVAL) {
 471             writeLong(e.csize);
 472             writeLong(e.size);
 473         } else {
 474             writeInt(e.csize);          // compressed size
 475             writeInt(e.size);           // uncompressed size
 476         }
 477     }
 478 
 479     /*
 480      * Write central directory (CEN) header for specified entry.
 481      * REMIND: add support for file attributes
 482      */
 483     private void writeCEN(XEntry xentry) throws IOException {
 484         ZipEntry e  = xentry.entry;
 485         int flag = e.flag;
 486         int version = version(e);
 487         long csize = e.csize;
 488         long size = e.size;
 489         long offset = xentry.offset;
 490         int elenZIP64 = 0;
 491         boolean hasZip64 = false;
 492 
 493         if (e.csize >= ZIP64_MAGICVAL) {
 494             csize = ZIP64_MAGICVAL;
 495             elenZIP64 += 8;              // csize(8)
 496             hasZip64 = true;
 497         }
 498         if (e.size >= ZIP64_MAGICVAL) {
 499             size = ZIP64_MAGICVAL;    // size(8)
 500             elenZIP64 += 8;
 501             hasZip64 = true;
 502         }
 503         if (xentry.offset >= ZIP64_MAGICVAL) {
 504             offset = ZIP64_MAGICVAL;
 505             elenZIP64 += 8;              // offset(8)
 506             hasZip64 = true;
 507         }
 508         writeInt(CENSIG);           // CEN header signature
 509         if (hasZip64) {
 510             writeShort(45);         // ver 4.5 for zip64
 511             writeShort(45);
 512         } else {
 513             writeShort(version);    // version made by
 514             writeShort(version);    // version needed to extract
 515         }
 516         writeShort(flag);           // general purpose bit flag
 517         writeShort(e.method);       // compression method
 518         writeInt(e.xdostime);       // last modification time
 519         writeInt(e.crc);            // crc-32
 520         writeInt(csize);            // compressed size
 521         writeInt(size);             // uncompressed size
 522         byte[] nameBytes = zc.getBytes(e.name);
 523         writeShort(nameBytes.length);
 524 
 525         int elen = getExtraLen(e.extra);
 526         if (hasZip64) {
 527             elen += (elenZIP64 + 4);// + headid(2) + datasize(2)
 528         }
 529         // cen info-zip extended timestamp only outputs mtime
 530         // but set the flag for a/ctime, if present in loc
 531         int flagEXTT = 0;
 532         if (e.mtime != null) {
 533             elen += 4;              // + mtime(4)
 534             flagEXTT |= EXTT_FLAG_LMT;
 535         }
 536         if (e.atime != null) {
 537             flagEXTT |= EXTT_FLAG_LAT;
 538         }
 539         if (e.ctime != null) {
 540             flagEXTT |= EXTT_FLAT_CT;
 541         }
 542         if (flagEXTT != 0) {
 543             elen += 5;             // headid + sz + flag
 544         }
 545         writeShort(elen);
 546         byte[] commentBytes;
 547         if (e.comment != null) {
 548             commentBytes = zc.getBytes(e.comment);
 549             writeShort(Math.min(commentBytes.length, 0xffff));
 550         } else {
 551             commentBytes = null;
 552             writeShort(0);
 553         }
 554         writeShort(0);              // starting disk number
 555         writeShort(0);              // internal file attributes (unused)
 556         writeInt(0);                // external file attributes (unused)
 557         writeInt(offset);           // relative offset of local header
 558         writeBytes(nameBytes, 0, nameBytes.length);
 559 
 560         // take care of EXTID_ZIP64 and EXTID_EXTT
 561         if (hasZip64) {
 562             writeShort(ZIP64_EXTID);// Zip64 extra
 563             writeShort(elenZIP64);
 564             if (size == ZIP64_MAGICVAL)
 565                 writeLong(e.size);
 566             if (csize == ZIP64_MAGICVAL)
 567                 writeLong(e.csize);
 568             if (offset == ZIP64_MAGICVAL)
 569                 writeLong(xentry.offset);
 570         }
 571         if (flagEXTT != 0) {
 572             writeShort(EXTID_EXTT);
 573             if (e.mtime != null) {
 574                 writeShort(5);      // flag + mtime
 575                 writeByte(flagEXTT);
 576                 writeInt(fileTimeToUnixTime(e.mtime));
 577             } else {
 578                 writeShort(1);      // flag only
 579                 writeByte(flagEXTT);
 580             }
 581         }
 582         writeExtra(e.extra);
 583         if (commentBytes != null) {
 584             writeBytes(commentBytes, 0, Math.min(commentBytes.length, 0xffff));
 585         }
 586     }
 587 
 588     /*
 589      * Writes end of central directory (END) header.
 590      */
 591     private void writeEND(long off, long len) throws IOException {
 592         boolean hasZip64 = false;
 593         long xlen = len;
 594         long xoff = off;
 595         if (xlen >= ZIP64_MAGICVAL) {
 596             xlen = ZIP64_MAGICVAL;
 597             hasZip64 = true;
 598         }
 599         if (xoff >= ZIP64_MAGICVAL) {
 600             xoff = ZIP64_MAGICVAL;
 601             hasZip64 = true;
 602         }
 603         int count = xentries.size();
 604         if (count >= ZIP64_MAGICCOUNT) {
 605             hasZip64 |= !inhibitZip64;
 606             if (hasZip64) {
 607                 count = ZIP64_MAGICCOUNT;
 608             }
 609         }
 610         if (hasZip64) {
 611             long off64 = written;
 612             //zip64 end of central directory record
 613             writeInt(ZIP64_ENDSIG);        // zip64 END record signature
 614             writeLong(ZIP64_ENDHDR - 12);  // size of zip64 end
 615             writeShort(45);                // version made by
 616             writeShort(45);                // version needed to extract
 617             writeInt(0);                   // number of this disk
 618             writeInt(0);                   // central directory start disk
 619             writeLong(xentries.size());    // number of directory entires on disk
 620             writeLong(xentries.size());    // number of directory entires
 621             writeLong(len);                // length of central directory
 622             writeLong(off);                // offset of central directory
 623 
 624             //zip64 end of central directory locator
 625             writeInt(ZIP64_LOCSIG);        // zip64 END locator signature
 626             writeInt(0);                   // zip64 END start disk
 627             writeLong(off64);              // offset of zip64 END
 628             writeInt(1);                   // total number of disks (?)
 629         }
 630         writeInt(ENDSIG);                 // END record signature
 631         writeShort(0);                    // number of this disk
 632         writeShort(0);                    // central directory start disk
 633         writeShort(count);                // number of directory entries on disk
 634         writeShort(count);                // total number of directory entries
 635         writeInt(xlen);                   // length of central directory
 636         writeInt(xoff);                   // offset of central directory
 637         if (comment != null) {            // zip file comment
 638             writeShort(comment.length);
 639             writeBytes(comment, 0, comment.length);
 640         } else {
 641             writeShort(0);
 642         }
 643     }
 644 
 645     /*
 646      * Returns the length of extra data without EXTT and ZIP64.
 647      */
 648     private int getExtraLen(byte[] extra) {
 649         if (extra == null)
 650             return 0;
 651         int skipped = 0;
 652         int len = extra.length;
 653         int off = 0;
 654         while (off + 4 <= len) {
 655             int tag = get16(extra, off);
 656             int sz = get16(extra, off + 2);
 657             if (sz < 0 || (off + 4 + sz) > len) {
 658                 break;
 659             }
 660             if (tag == EXTID_EXTT || tag == EXTID_ZIP64) {
 661                 skipped += (sz + 4);
 662             }
 663             off += (sz + 4);
 664         }
 665         return len - skipped;
 666     }
 667 
 668     /*
 669      * Writes extra data without EXTT and ZIP64.
 670      *
 671      * Extra timestamp and ZIP64 data is handled/output separately
 672      * in writeLOC and writeCEN.
 673      */
 674     private void writeExtra(byte[] extra) throws IOException {
 675         if (extra != null) {
 676             int len = extra.length;
 677             int off = 0;
 678             while (off + 4 <= len) {
 679                 int tag = get16(extra, off);
 680                 int sz = get16(extra, off + 2);
 681                 if (sz < 0 || (off + 4 + sz) > len) {
 682                     writeBytes(extra, off, len - off);
 683                     return;
 684                 }
 685                 if (tag != EXTID_EXTT && tag != EXTID_ZIP64) {
 686                     writeBytes(extra, off, sz + 4);
 687                 }
 688                 off += (sz + 4);
 689             }
 690             if (off < len) {
 691                 writeBytes(extra, off, len - off);
 692             }
 693         }
 694     }
 695 
 696     /*
 697      * Writes a 8-bit byte to the output stream.
 698      */
 699     private void writeByte(int v) throws IOException {
 700         OutputStream out = this.out;
 701         out.write(v & 0xff);
 702         written += 1;
 703     }
 704 
 705     /*
 706      * Writes a 16-bit short to the output stream in little-endian byte order.
 707      */
 708     private void writeShort(int v) throws IOException {
 709         OutputStream out = this.out;
 710         out.write((v >>> 0) & 0xff);
 711         out.write((v >>> 8) & 0xff);
 712         written += 2;
 713     }
 714 
 715     /*
 716      * Writes a 32-bit int to the output stream in little-endian byte order.
 717      */
 718     private void writeInt(long v) throws IOException {
 719         OutputStream out = this.out;
 720         out.write((int)((v >>>  0) & 0xff));
 721         out.write((int)((v >>>  8) & 0xff));
 722         out.write((int)((v >>> 16) & 0xff));
 723         out.write((int)((v >>> 24) & 0xff));
 724         written += 4;
 725     }
 726 
 727     /*
 728      * Writes a 64-bit int to the output stream in little-endian byte order.
 729      */
 730     private void writeLong(long v) throws IOException {
 731         OutputStream out = this.out;
 732         out.write((int)((v >>>  0) & 0xff));
 733         out.write((int)((v >>>  8) & 0xff));
 734         out.write((int)((v >>> 16) & 0xff));
 735         out.write((int)((v >>> 24) & 0xff));
 736         out.write((int)((v >>> 32) & 0xff));
 737         out.write((int)((v >>> 40) & 0xff));
 738         out.write((int)((v >>> 48) & 0xff));
 739         out.write((int)((v >>> 56) & 0xff));
 740         written += 8;
 741     }
 742 
 743     /*
 744      * Writes an array of bytes to the output stream.
 745      */
 746     private void writeBytes(byte[] b, int off, int len) throws IOException {
 747         super.out.write(b, off, len);
 748         written += len;
 749     }
 750 }
--- EOF ---