https://openjdk.java.net/ 
/*
 * Copyright (c) 1995, 2017, 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
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 * questions.
 */

package java.util.zip;

import java.io.Closeable;
import java.io.InputStream;
import java.io.IOException;
import java.io.EOFException;
import java.io.File;
import java.io.RandomAccessFile;
import java.io.UncheckedIOException;
import java.lang.ref.Cleaner.Cleanable;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.nio.file.attribute.BasicFileAttributes;
import java.nio.file.Files;

import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Deque;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Objects;
import java.util.NoSuchElementException;
import java.util.Set;
import java.util.Spliterator;
import java.util.Spliterators;
import java.util.WeakHashMap;

import java.util.function.Consumer;
import java.util.function.Function;
import java.util.function.IntFunction;
import java.util.jar.JarEntry;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;
import jdk.internal.misc.JavaUtilZipFileAccess;
import jdk.internal.misc.SharedSecrets;
import jdk.internal.misc.VM;
import jdk.internal.perf.PerfCounter;
import jdk.internal.ref.CleanerFactory;

import static java.util.zip.ZipConstants64.*;
import static java.util.zip.ZipUtils.*;


This class is used to read entries from a zip file.

 Unless otherwise noted, passing a null argument to a constructor or method in this class will cause a NullPointerException to be thrown. 
Author:     David Connelly
API Note: To release resources used by this ZipFile, the close() method should be called explicitly or by try-with-resources. Subclasses are responsible for the cleanup of resources acquired by the subclass. Subclasses that override finalize() in order to perform cleanup should be modified to use alternative cleanup mechanisms such as Cleaner and remove the overriding finalize method.
Implementation Requirements: If this ZipFile has been subclassed and the close method has been overridden, the close method will be called by the finalization when ZipFile is unreachable. But the subclasses should not depend on this specific implementation; the finalization is not reliable and the finalize method is deprecated to be removed.
Since:1.1
/**
 * This class is used to read entries from a zip file.
 *
 * <p> Unless otherwise noted, passing a {@code null} argument to a constructor
 * or method in this class will cause a {@link NullPointerException} to be
 * thrown.
 *
 * @apiNote
 * To release resources used by this {@code ZipFile}, the {@link #close()} method
 * should be called explicitly or by try-with-resources. Subclasses are responsible
 * for the cleanup of resources acquired by the subclass. Subclasses that override
 * {@link #finalize()} in order to perform cleanup should be modified to use alternative
 * cleanup mechanisms such as {@link java.lang.ref.Cleaner} and remove the overriding
 * {@code finalize} method.
 *
 * @implSpec
 * If this {@code ZipFile} has been subclassed and the {@code close} method has
 * been overridden, the {@code close} method will be called by the finalization
 * when {@code ZipFile} is unreachable. But the subclasses should not depend on
 * this specific implementation; the finalization is not reliable and the
 * {@code finalize} method is deprecated to be removed.
 *
 * @author      David Connelly
 * @since 1.1
 */
public
class ZipFile implements ZipConstants, Closeable {

    private final String name;     // zip file name
    private volatile boolean closeRequested;
    private ZipCoder zc;

    // The "resource" used by this zip file that needs to be
    // cleaned after use.
    // a) the input streams that need to be closed
    // b) the list of cached Inflater objects
    // c) the "native" source of this zip file.
    private final CleanableResource res;

    private static final int STORED = ZipEntry.STORED;
    private static final int DEFLATED = ZipEntry.DEFLATED;

    
Mode flag to open a zip file for reading.

/**
     * Mode flag to open a zip file for reading.
     */
    public static final int OPEN_READ = 0x1;

    
Mode flag to open a zip file and mark it for deletion. The file will be deleted some time between the moment that it is opened and the moment that it is closed, but its contents will remain accessible via the ZipFile object until either the close method is invoked or the virtual machine exits. 
/**
     * Mode flag to open a zip file and mark it for deletion.  The file will be
     * deleted some time between the moment that it is opened and the moment
     * that it is closed, but its contents will remain accessible via the
     * {@code ZipFile} object until either the close method is invoked or the
     * virtual machine exits.
     */
    public static final int OPEN_DELETE = 0x4;

    
Opens a zip file for reading.

First, if there is a security manager, its checkRead method is called with the name argument as its argument to ensure the read is allowed. 
The UTF-8 charset is used to decode the entry names and comments. 
Params:
  • name – the name of the zip file
Throws:
  • ZipException – if a ZIP format error has occurred
  • IOException – if an I/O error has occurred
  • SecurityException – if a security manager exists and its checkRead method doesn't allow read access to the file.
See Also:
/**
     * Opens a zip file for reading.
     *
     * <p>First, if there is a security manager, its {@code checkRead}
     * method is called with the {@code name} argument as its argument
     * to ensure the read is allowed.
     *
     * <p>The UTF-8 {@link java.nio.charset.Charset charset} is used to
     * decode the entry names and comments.
     *
     * @param name the name of the zip file
     * @throws ZipException if a ZIP format error has occurred
     * @throws IOException if an I/O error has occurred
     * @throws SecurityException if a security manager exists and its
     *         {@code checkRead} method doesn't allow read access to the file.
     *
     * @see SecurityManager#checkRead(java.lang.String)
     */
    public ZipFile(String name) throws IOException {
        this(new File(name), OPEN_READ);
    }

    
Opens a new ZipFile to read from the specified File object in the specified mode. The mode argument must be either OPEN_READ or OPEN_READ | OPEN_DELETE. 
First, if there is a security manager, its checkRead method is called with the name argument as its argument to ensure the read is allowed. 
The UTF-8 charset is used to decode the entry names and comments 
Params:
  • file – the ZIP file to be opened for reading
  • mode – the mode in which the file is to be opened
Throws:
  • ZipException – if a ZIP format error has occurred
  • IOException – if an I/O error has occurred
  • SecurityException – if a security manager exists and its checkRead method doesn't allow read access to the file, or its checkDelete method doesn't allow deleting the file when the OPEN_DELETE flag is set.
  • IllegalArgumentException – if the mode argument is invalid
See Also:
Since:1.3
/**
     * Opens a new {@code ZipFile} to read from the specified
     * {@code File} object in the specified mode.  The mode argument
     * must be either {@code OPEN_READ} or {@code OPEN_READ | OPEN_DELETE}.
     *
     * <p>First, if there is a security manager, its {@code checkRead}
     * method is called with the {@code name} argument as its argument to
     * ensure the read is allowed.
     *
     * <p>The UTF-8 {@link java.nio.charset.Charset charset} is used to
     * decode the entry names and comments
     *
     * @param file the ZIP file to be opened for reading
     * @param mode the mode in which the file is to be opened
     * @throws ZipException if a ZIP format error has occurred
     * @throws IOException if an I/O error has occurred
     * @throws SecurityException if a security manager exists and
     *         its {@code checkRead} method
     *         doesn't allow read access to the file,
     *         or its {@code checkDelete} method doesn't allow deleting
     *         the file when the {@code OPEN_DELETE} flag is set.
     * @throws IllegalArgumentException if the {@code mode} argument is invalid
     * @see SecurityManager#checkRead(java.lang.String)
     * @since 1.3
     */
    public ZipFile(File file, int mode) throws IOException {
        this(file, mode, StandardCharsets.UTF_8);
    }

    
Opens a ZIP file for reading given the specified File object.

The UTF-8 charset is used to decode the entry names and comments. 
Params:
  • file – the ZIP file to be opened for reading
Throws:
/**
     * Opens a ZIP file for reading given the specified File object.
     *
     * <p>The UTF-8 {@link java.nio.charset.Charset charset} is used to
     * decode the entry names and comments.
     *
     * @param file the ZIP file to be opened for reading
     * @throws ZipException if a ZIP format error has occurred
     * @throws IOException if an I/O error has occurred
     */
    public ZipFile(File file) throws ZipException, IOException {
        this(file, OPEN_READ);
    }

    
Opens a new ZipFile to read from the specified File object in the specified mode. The mode argument must be either OPEN_READ or OPEN_READ | OPEN_DELETE. 
First, if there is a security manager, its checkRead method is called with the name argument as its argument to ensure the read is allowed. 
Params:
  • file – the ZIP file to be opened for reading
  • mode – the mode in which the file is to be opened
  • charset –  the charset to be used to decode the ZIP entry name and comment that are not encoded by using UTF-8 encoding (indicated by entry's general purpose flag).
Throws:
  • ZipException – if a ZIP format error has occurred
  • IOException – if an I/O error has occurred
  • SecurityException –  if a security manager exists and its checkRead method doesn't allow read access to the file,or its checkDelete method doesn't allow deleting the file when the OPEN_DELETE flag is set
  • IllegalArgumentException – if the mode argument is invalid
See Also:
Since:1.7
/**
     * Opens a new {@code ZipFile} to read from the specified
     * {@code File} object in the specified mode.  The mode argument
     * must be either {@code OPEN_READ} or {@code OPEN_READ | OPEN_DELETE}.
     *
     * <p>First, if there is a security manager, its {@code checkRead}
     * method is called with the {@code name} argument as its argument to
     * ensure the read is allowed.
     *
     * @param file the ZIP file to be opened for reading
     * @param mode the mode in which the file is to be opened
     * @param charset
     *        the {@linkplain java.nio.charset.Charset charset} to
     *        be used to decode the ZIP entry name and comment that are not
     *        encoded by using UTF-8 encoding (indicated by entry's general
     *        purpose flag).
     *
     * @throws ZipException if a ZIP format error has occurred
     * @throws IOException if an I/O error has occurred
     *
     * @throws SecurityException
     *         if a security manager exists and its {@code checkRead}
     *         method doesn't allow read access to the file,or its
     *         {@code checkDelete} method doesn't allow deleting the
     *         file when the {@code OPEN_DELETE} flag is set
     *
     * @throws IllegalArgumentException if the {@code mode} argument is invalid
     *
     * @see SecurityManager#checkRead(java.lang.String)
     *
     * @since 1.7
     */
    public ZipFile(File file, int mode, Charset charset) throws IOException
    {
        if (((mode & OPEN_READ) == 0) ||
            ((mode & ~(OPEN_READ | OPEN_DELETE)) != 0)) {
            throw new IllegalArgumentException("Illegal mode: 0x"+
                                               Integer.toHexString(mode));
        }
        String name = file.getPath();
        SecurityManager sm = System.getSecurityManager();
        if (sm != null) {
            sm.checkRead(name);
            if ((mode & OPEN_DELETE) != 0) {
                sm.checkDelete(name);
            }
        }
        Objects.requireNonNull(charset, "charset");

        this.zc = ZipCoder.get(charset);
        this.name = name;
        long t0 = System.nanoTime();

        this.res = CleanableResource.get(this, file, mode);

        PerfCounter.getZipFileOpenTime().addElapsedTimeFrom(t0);
        PerfCounter.getZipFileCount().increment();
    }

    
Opens a zip file for reading.

First, if there is a security manager, its checkRead method is called with the name argument as its argument to ensure the read is allowed. 
Params:
  • name – the name of the zip file
  • charset –  the charset to be used to decode the ZIP entry name and comment that are not encoded by using UTF-8 encoding (indicated by entry's general purpose flag).
Throws:
  • ZipException – if a ZIP format error has occurred
  • IOException – if an I/O error has occurred
  • SecurityException –  if a security manager exists and its checkRead method doesn't allow read access to the file
See Also:
Since:1.7
/**
     * Opens a zip file for reading.
     *
     * <p>First, if there is a security manager, its {@code checkRead}
     * method is called with the {@code name} argument as its argument
     * to ensure the read is allowed.
     *
     * @param name the name of the zip file
     * @param charset
     *        the {@linkplain java.nio.charset.Charset charset} to
     *        be used to decode the ZIP entry name and comment that are not
     *        encoded by using UTF-8 encoding (indicated by entry's general
     *        purpose flag).
     *
     * @throws ZipException if a ZIP format error has occurred
     * @throws IOException if an I/O error has occurred
     * @throws SecurityException
     *         if a security manager exists and its {@code checkRead}
     *         method doesn't allow read access to the file
     *
     * @see SecurityManager#checkRead(java.lang.String)
     *
     * @since 1.7
     */
    public ZipFile(String name, Charset charset) throws IOException
    {
        this(new File(name), OPEN_READ, charset);
    }

    
Opens a ZIP file for reading given the specified File object.

Params:
  • file – the ZIP file to be opened for reading
  • charset –  The charset to be used to decode the ZIP entry name and comment (ignored if the  language
       encoding bit of the ZIP entry's general purpose bit
       flag is set).
Throws:
Since:1.7
/**
     * Opens a ZIP file for reading given the specified File object.
     *
     * @param file the ZIP file to be opened for reading
     * @param charset
     *        The {@linkplain java.nio.charset.Charset charset} to be
     *        used to decode the ZIP entry name and comment (ignored if
     *        the <a href="package-summary.html#lang_encoding"> language
     *        encoding bit</a> of the ZIP entry's general purpose bit
     *        flag is set).
     *
     * @throws ZipException if a ZIP format error has occurred
     * @throws IOException if an I/O error has occurred
     *
     * @since 1.7
     */
    public ZipFile(File file, Charset charset) throws IOException
    {
        this(file, OPEN_READ, charset);
    }

    
Returns the zip file comment, or null if none.

Throws:
Returns:the comment string for the zip file, or null if none
Since:1.7
/**
     * Returns the zip file comment, or null if none.
     *
     * @return the comment string for the zip file, or null if none
     *
     * @throws IllegalStateException if the zip file has been closed
     *
     * @since 1.7
     */
    public String getComment() {
        synchronized (this) {
            ensureOpen();
            if (res.zsrc.comment == null) {
                return null;
            }
            return zc.toString(res.zsrc.comment);
        }
    }

    
Returns the zip file entry for the specified name, or null
if not found.

Params:
  • name – the name of the entry
Throws:
Returns:the zip file entry, or null if not found
/**
     * Returns the zip file entry for the specified name, or null
     * if not found.
     *
     * @param name the name of the entry
     * @return the zip file entry, or null if not found
     * @throws IllegalStateException if the zip file has been closed
     */
    public ZipEntry getEntry(String name) {
        return getEntry(name, ZipEntry::new);
    }

    /*
     * Returns the zip file entry for the specified name, or null
     * if not found.
     *
     * @param name the name of the entry
     * @param func the function that creates the returned entry
     *
     * @return the zip file entry, or null if not found
     * @throws IllegalStateException if the zip file has been closed
     */
    private ZipEntry getEntry(String name, Function<String, ? extends ZipEntry> func) {
        Objects.requireNonNull(name, "name");
        synchronized (this) {
            ensureOpen();
            byte[] bname = zc.getBytes(name);
            int pos = res.zsrc.getEntryPos(bname, true);
            if (pos != -1) {
                return getZipEntry(name, bname, pos, func);
            }
        }
        return null;
    }

    
Returns an input stream for reading the contents of the specified
zip file entry.


Closing this ZIP file will, in turn, close all input streams that
have been returned by invocations of this method.

Params:
  • entry – the zip file entry
Throws:
Returns:the input stream for reading the contents of the specified
zip file entry.
/**
     * Returns an input stream for reading the contents of the specified
     * zip file entry.
     * <p>
     * Closing this ZIP file will, in turn, close all input streams that
     * have been returned by invocations of this method.
     *
     * @param entry the zip file entry
     * @return the input stream for reading the contents of the specified
     * zip file entry.
     * @throws ZipException if a ZIP format error has occurred
     * @throws IOException if an I/O error has occurred
     * @throws IllegalStateException if the zip file has been closed
     */
    public InputStream getInputStream(ZipEntry entry) throws IOException {
        Objects.requireNonNull(entry, "entry");
        int pos = -1;
        ZipFileInputStream in = null;
        Source zsrc = res.zsrc;
        Set<InputStream> istreams = res.istreams;
        synchronized (this) {
            ensureOpen();
            if (Objects.equals(lastEntryName, entry.name)) {
                pos = lastEntryPos;
            } else if (!zc.isUTF8() && (entry.flag & EFS) != 0) {
                pos = zsrc.getEntryPos(zc.getBytesUTF8(entry.name), false);
            } else {
                pos = zsrc.getEntryPos(zc.getBytes(entry.name), false);
            }
            if (pos == -1) {
                return null;
            }
            in = new ZipFileInputStream(zsrc.cen, pos);
            switch (CENHOW(zsrc.cen, pos)) {
            case STORED:
                synchronized (istreams) {
                    istreams.add(in);
                }
                return in;
            case DEFLATED:
                // Inflater likes a bit of slack
                // MORE: Compute good size for inflater stream:
                long size = CENLEN(zsrc.cen, pos) + 2;
                if (size > 65536) {
                    size = 8192;
                }
                if (size <= 0) {
                    size = 4096;
                }
                InputStream is = new ZipFileInflaterInputStream(in, res, (int)size);
                synchronized (istreams) {
                    istreams.add(is);
                }
                return is;
            default:
                throw new ZipException("invalid compression method");
            }
        }
    }

    private static class InflaterCleanupAction implements Runnable {
        private final Inflater inf;
        private final CleanableResource res;

        InflaterCleanupAction(Inflater inf, CleanableResource res) {
            this.inf = inf;
            this.res = res;
        }

        @Override
        public void run() {
            res.releaseInflater(inf);
        }
    }

    private class ZipFileInflaterInputStream extends InflaterInputStream {
        private volatile boolean closeRequested;
        private boolean eof = false;
        private final Cleanable cleanable;

        ZipFileInflaterInputStream(ZipFileInputStream zfin,
                                   CleanableResource res, int size) {
            this(zfin, res, res.getInflater(), size);
        }

        private ZipFileInflaterInputStream(ZipFileInputStream zfin,
                                           CleanableResource res,
                                           Inflater inf, int size) {
            super(zfin, inf, size);
            this.cleanable = CleanerFactory.cleaner().register(this,
                    new InflaterCleanupAction(inf, res));
        }

        public void close() throws IOException {
            if (closeRequested)
                return;
            closeRequested = true;
            super.close();
            synchronized (res.istreams) {
                res.istreams.remove(this);
            }
            cleanable.clean();
        }

        // Override fill() method to provide an extra "dummy" byte
        // at the end of the input stream. This is required when
        // using the "nowrap" Inflater option.
        protected void fill() throws IOException {
            if (eof) {
                throw new EOFException("Unexpected end of ZLIB input stream");
            }
            len = in.read(buf, 0, buf.length);
            if (len == -1) {
                buf[0] = 0;
                len = 1;
                eof = true;
            }
            inf.setInput(buf, 0, len);
        }

        public int available() throws IOException {
            if (closeRequested)
                return 0;
            long avail = ((ZipFileInputStream)in).size() - inf.getBytesWritten();
            return (avail > (long) Integer.MAX_VALUE ?
                    Integer.MAX_VALUE : (int) avail);
        }
    }

    
Returns the path name of the ZIP file.

Returns:the path name of the ZIP file
/**
     * Returns the path name of the ZIP file.
     * @return the path name of the ZIP file
     */
    public String getName() {
        return name;
    }

    private class ZipEntryIterator<T extends ZipEntry>
            implements Enumeration<T>, Iterator<T> {

        private int i = 0;
        private final int entryCount;
        private final Function<String, T> gen;

        public ZipEntryIterator(int entryCount, Function<String, T> gen) {
            this.entryCount = entryCount;
            this.gen = gen;
        }

        @Override
        public boolean hasMoreElements() {
            return hasNext();
        }

        @Override
        public boolean hasNext() {
            return i < entryCount;
        }

        @Override
        public T nextElement() {
            return next();
        }

        @Override
        @SuppressWarnings("unchecked")
        public T  next() {
            synchronized (ZipFile.this) {
                ensureOpen();
                if (!hasNext()) {
                    throw new NoSuchElementException();
                }
                // each "entry" has 3 ints in table entries
                return (T)getZipEntry(null, null, res.zsrc.getEntryPos(i++ * 3), gen);
            }
        }

        @Override
        public Iterator<T> asIterator() {
            return this;
        }
    }

    
Returns an enumeration of the ZIP file entries.

Throws:
Returns:an enumeration of the ZIP file entries
/**
     * Returns an enumeration of the ZIP file entries.
     * @return an enumeration of the ZIP file entries
     * @throws IllegalStateException if the zip file has been closed
     */
    public Enumeration<? extends ZipEntry> entries() {
        synchronized (this) {
            ensureOpen();
            return new ZipEntryIterator<ZipEntry>(res.zsrc.total, ZipEntry::new);
        }
    }

    private Enumeration<JarEntry> entries(Function<String, JarEntry> func) {
        synchronized (this) {
            ensureOpen();
            return new ZipEntryIterator<JarEntry>(res.zsrc.total, func);
        }
    }

    private class EntrySpliterator<T> extends Spliterators.AbstractSpliterator<T> {
        private int index;
        private final int fence;
        private final IntFunction<T> gen;

        EntrySpliterator(int index, int fence, IntFunction<T> gen) {
            super((long)fence,
                  Spliterator.ORDERED | Spliterator.DISTINCT | Spliterator.IMMUTABLE |
                  Spliterator.NONNULL);
            this.index = index;
            this.fence = fence;
            this.gen = gen;
        }

        @Override
        public boolean tryAdvance(Consumer<? super T> action) {
            if (action == null)
                throw new NullPointerException();
            if (index >= 0 && index < fence) {
                synchronized (ZipFile.this) {
                    ensureOpen();
                    action.accept(gen.apply(res.zsrc.getEntryPos(index++ * 3)));
                }
                return true;
            }
            return false;
        }
    }

    
Returns an ordered Stream over the ZIP file entries. Entries appear in the Stream in the order they appear in the central directory of the ZIP file. 
Throws:
Returns:an ordered Stream of entries in this ZIP file
Since:1.8
/**
     * Returns an ordered {@code Stream} over the ZIP file entries.
     *
     * Entries appear in the {@code Stream} in the order they appear in
     * the central directory of the ZIP file.
     *
     * @return an ordered {@code Stream} of entries in this ZIP file
     * @throws IllegalStateException if the zip file has been closed
     * @since 1.8
     */
    public Stream<? extends ZipEntry> stream() {
        synchronized (this) {
            ensureOpen();
            return StreamSupport.stream(new EntrySpliterator<>(0, res.zsrc.total,
                pos -> getZipEntry(null, null, pos, ZipEntry::new)), false);
       }
    }

    private String getEntryName(int pos) {
        byte[] cen = res.zsrc.cen;
        int nlen = CENNAM(cen, pos);
        int clen = CENCOM(cen, pos);
        int flag = CENFLG(cen, pos);
        if (!zc.isUTF8() && (flag & EFS) != 0) {
            return zc.toStringUTF8(cen, pos + CENHDR, nlen);
        } else {
            return zc.toString(cen, pos + CENHDR, nlen);
        }
    }

    /*
     * Returns an ordered {@code Stream} over the zip file entry names.
     *
     * Entry names appear in the {@code Stream} in the order they appear in
     * the central directory of the ZIP file.
     *
     * @return an ordered {@code Stream} of entry names in this zip file
     * @throws IllegalStateException if the zip file has been closed
     * @since 10
     */
    private Stream<String> entryNameStream() {
        synchronized (this) {
            ensureOpen();
            return StreamSupport.stream(
                new EntrySpliterator<>(0, res.zsrc.total, this::getEntryName), false);
        }
    }

    /*
     * Returns an ordered {@code Stream} over the zip file entries.
     *
     * Entries appear in the {@code Stream} in the order they appear in
     * the central directory of the jar file.
     *
     * @param func the function that creates the returned entry
     * @return an ordered {@code Stream} of entries in this zip file
     * @throws IllegalStateException if the zip file has been closed
     * @since 10
     */
    private Stream<JarEntry> stream(Function<String, JarEntry> func) {
        synchronized (this) {
            ensureOpen();
            return StreamSupport.stream(new EntrySpliterator<>(0, res.zsrc.total,
                pos -> (JarEntry)getZipEntry(null, null, pos, func)), false);
        }
    }

    private String lastEntryName;
    private int lastEntryPos;

    /* Checks ensureOpen() before invoke this method */
    private ZipEntry getZipEntry(String name, byte[] bname, int pos,
                                 Function<String, ? extends ZipEntry> func) {
        byte[] cen = res.zsrc.cen;
        int nlen = CENNAM(cen, pos);
        int elen = CENEXT(cen, pos);
        int clen = CENCOM(cen, pos);
        int flag = CENFLG(cen, pos);
        if (name == null || bname.length != nlen) {
            // to use the entry name stored in cen, if the passed in name is
            // (1) null, invoked from iterator, or
            // (2) not equal to the name stored, a slash is appended during
            // getEntryPos() search.
            if (!zc.isUTF8() && (flag & EFS) != 0) {
                name = zc.toStringUTF8(cen, pos + CENHDR, nlen);
            } else {
                name = zc.toString(cen, pos + CENHDR, nlen);
            }
        }
        ZipEntry e = func.apply(name);    //ZipEntry e = new ZipEntry(name);
        e.flag = flag;
        e.xdostime = CENTIM(cen, pos);
        e.crc = CENCRC(cen, pos);
        e.size = CENLEN(cen, pos);
        e.csize = CENSIZ(cen, pos);
        e.method = CENHOW(cen, pos);
        if (elen != 0) {
            int start = pos + CENHDR + nlen;
            e.setExtra0(Arrays.copyOfRange(cen, start, start + elen), true);
        }
        if (clen != 0) {
            int start = pos + CENHDR + nlen + elen;
            if (!zc.isUTF8() && (flag & EFS) != 0) {
                e.comment = zc.toStringUTF8(cen, start, clen);
            } else {
                e.comment = zc.toString(cen, start, clen);
            }
        }
        lastEntryName = e.name;
        lastEntryPos = pos;
        return e;
    }

    
Returns the number of entries in the ZIP file.

Throws:
Returns:the number of entries in the ZIP file
/**
     * Returns the number of entries in the ZIP file.
     *
     * @return the number of entries in the ZIP file
     * @throws IllegalStateException if the zip file has been closed
     */
    public int size() {
        synchronized (this) {
            ensureOpen();
            return res.zsrc.total;
        }
    }

    private static class CleanableResource implements Runnable {
        // The outstanding inputstreams that need to be closed
        final Set<InputStream> istreams;

        // List of cached Inflater objects for decompression
        Deque<Inflater> inflaterCache;

        final Cleanable cleanable;

        Source zsrc;

        CleanableResource(ZipFile zf, File file, int mode) throws IOException {
            this.cleanable = CleanerFactory.cleaner().register(zf, this);
            this.istreams = Collections.newSetFromMap(new WeakHashMap<>());
            this.inflaterCache = new ArrayDeque<>();
            this.zsrc = Source.get(file, (mode & OPEN_DELETE) != 0);
        }

        void clean() {
            cleanable.clean();
        }

        /*
         * Gets an inflater from the list of available inflaters or allocates
         * a new one.
         */
        Inflater getInflater() {
            Inflater inf;
            synchronized (inflaterCache) {
                if ((inf = inflaterCache.poll()) != null) {
                    return inf;
                }
            }
            return new Inflater(true);
        }

        /*
         * Releases the specified inflater to the list of available inflaters.
         */
        void releaseInflater(Inflater inf) {
            Deque<Inflater> inflaters = this.inflaterCache;
            if (inflaters != null) {
                synchronized (inflaters) {
                    // double checked!
                    if (inflaters == this.inflaterCache) {
                        inf.reset();
                        inflaters.add(inf);
                        return;
                    }
                }
            }
            // inflaters cache already closed - just end it.
            inf.end();
        }

        public void run() {
            IOException ioe = null;

            // Release cached inflaters and close the cache first
            Deque<Inflater> inflaters = this.inflaterCache;
            if (inflaters != null) {
                synchronized (inflaters) {
                    // no need to double-check as only one thread gets a
                    // chance to execute run() (Cleaner guarantee)...
                    Inflater inf;
                    while ((inf = inflaters.poll()) != null) {
                        inf.end();
                    }
                    // close inflaters cache
                    this.inflaterCache = null;
                }
            }

            // Close streams, release their inflaters
            if (istreams != null) {
                synchronized (istreams) {
                    if (!istreams.isEmpty()) {
                        InputStream[] copy = istreams.toArray(new InputStream[0]);
                        istreams.clear();
                        for (InputStream is : copy) {
                            try {
                                is.close();
                            }  catch (IOException e) {
                                if (ioe == null) ioe = e;
                                else ioe.addSuppressed(e);
                            }
                        }
                    }
                }
            }

            // Release zip src
            if (zsrc != null) {
                synchronized (zsrc) {
                    try {
                        Source.release(zsrc);
                        zsrc = null;
                     }  catch (IOException e) {
                         if (ioe == null) ioe = e;
                         else ioe.addSuppressed(e);
                    }
                }
            }
            if (ioe != null) {
                throw new UncheckedIOException(ioe);
            }
        }

        CleanableResource(File file, int mode)
            throws IOException {
            this.cleanable = null;
            this.istreams = Collections.newSetFromMap(new WeakHashMap<>());
            this.inflaterCache = new ArrayDeque<>();
            this.zsrc = Source.get(file, (mode & OPEN_DELETE) != 0);
        }

        /*
         * If {@code ZipFile} has been subclassed and the {@code close} method is
         * overridden, uses the {@code finalizer} mechanism for resource cleanup.
         * So {@code close} method can be called when the the {@code ZipFile} is
         * unreachable. This mechanism will be removed when {@code finalize} method
         * is removed from {@code ZipFile}.
         */
        static CleanableResource get(ZipFile zf, File file, int mode)
            throws IOException {
            Class<?> clz = zf.getClass();
            while (clz != ZipFile.class) {
                try {
                    clz.getDeclaredMethod("close");
                    return new FinalizableResource(zf, file, mode);
                } catch (NoSuchMethodException nsme) {}
                clz = clz.getSuperclass();
            }
            return new CleanableResource(zf, file, mode);
        }

        static class FinalizableResource extends CleanableResource {
            ZipFile zf;
            FinalizableResource(ZipFile zf, File file, int mode)
                throws IOException {
                super(file, mode);
                this.zf = zf;
            }

            @Override
            void clean() {
                run();
            }

            @Override
            @SuppressWarnings("deprecation")
            protected void finalize() throws IOException {
                zf.close();
            }
        }
    }

    
Closes the ZIP file.

 Closing this ZIP file will close all of the input streams previously returned by invocations of the 
getInputStream method. 
Throws:
/**
     * Closes the ZIP file.
     *
     * <p> Closing this ZIP file will close all of the input streams
     * previously returned by invocations of the {@link #getInputStream
     * getInputStream} method.
     *
     * @throws IOException if an I/O error has occurred
     */
    public void close() throws IOException {
        if (closeRequested) {
            return;
        }
        closeRequested = true;

        synchronized (this) {
            // Close streams, release their inflaters, release cached inflaters
            // and release zip source
            try {
                res.clean();
            } catch (UncheckedIOException ioe) {
                throw ioe.getCause();
            }
        }
    }

    
Ensures that the system resources held by this ZipFile object are
released when there are no more references to it.

Throws:
Deprecated:The finalize method has been deprecated and will be removed. It is implemented as a no-op. Subclasses that override finalize in order to perform cleanup should be modified to use alternative cleanup mechanisms and to remove the overriding finalize method. The recommended cleanup for ZipFile object is to explicitly invoke close method when it is no longer in use, or use try-with-resources. If the close is not invoked explicitly the resources held by this object will be released when the instance becomes unreachable.
/**
     * Ensures that the system resources held by this ZipFile object are
     * released when there are no more references to it.
     *
     * @deprecated The {@code finalize} method has been deprecated and will be
     *     removed. It is implemented as a no-op. Subclasses that override
     *     {@code finalize} in order to perform cleanup should be modified to
     *     use alternative cleanup mechanisms and to remove the overriding
     *     {@code finalize} method. The recommended cleanup for ZipFile object
     *     is to explicitly invoke {@code close} method when it is no longer in
     *     use, or use try-with-resources. If the {@code close} is not invoked
     *     explicitly the resources held by this object will be released when
     *     the instance becomes unreachable.
     *
     * @throws IOException if an I/O error has occurred
     */
    @Deprecated(since="9", forRemoval=true)
    protected void finalize() throws IOException {}

    private void ensureOpen() {
        if (closeRequested) {
            throw new IllegalStateException("zip file closed");
        }
        if (res.zsrc == null) {
            throw new IllegalStateException("The object is not initialized.");
        }
    }

    private void ensureOpenOrZipException() throws IOException {
        if (closeRequested) {
            throw new ZipException("ZipFile closed");
        }
    }

    /*
     * Inner class implementing the input stream used to read a
     * (possibly compressed) zip file entry.
     */
   private class ZipFileInputStream extends InputStream {
        private volatile boolean closeRequested;
        private   long pos;     // current position within entry data
        protected long rem;     // number of remaining bytes within entry
        protected long size;    // uncompressed size of this entry

        ZipFileInputStream(byte[] cen, int cenpos) {
            rem = CENSIZ(cen, cenpos);
            size = CENLEN(cen, cenpos);
            pos = CENOFF(cen, cenpos);
            // zip64
            if (rem == ZIP64_MAGICVAL || size == ZIP64_MAGICVAL ||
                pos == ZIP64_MAGICVAL) {
                checkZIP64(cen, cenpos);
            }
            // negative for lazy initialization, see getDataOffset();
            pos = - (pos + ZipFile.this.res.zsrc.locpos);
        }

         private void checkZIP64(byte[] cen, int cenpos) {
            int off = cenpos + CENHDR + CENNAM(cen, cenpos);
            int end = off + CENEXT(cen, cenpos);
            while (off + 4 < end) {
                int tag = get16(cen, off);
                int sz = get16(cen, off + 2);
                off += 4;
                if (off + sz > end)         // invalid data
                    break;
                if (tag == EXTID_ZIP64) {
                    if (size == ZIP64_MAGICVAL) {
                        if (sz < 8 || (off + 8) > end)
                            break;
                        size = get64(cen, off);
                        sz -= 8;
                        off += 8;
                    }
                    if (rem == ZIP64_MAGICVAL) {
                        if (sz < 8 || (off + 8) > end)
                            break;
                        rem = get64(cen, off);
                        sz -= 8;
                        off += 8;
                    }
                    if (pos == ZIP64_MAGICVAL) {
                        if (sz < 8 || (off + 8) > end)
                            break;
                        pos = get64(cen, off);
                        sz -= 8;
                        off += 8;
                    }
                    break;
                }
                off += sz;
            }
        }

       /* The Zip file spec explicitly allows the LOC extra data size to
        * be different from the CEN extra data size. Since we cannot trust
        * the CEN extra data size, we need to read the LOC to determine
        * the entry data offset.
        */
        private long initDataOffset() throws IOException {
            if (pos <= 0) {
                byte[] loc = new byte[LOCHDR];
                pos = -pos;
                int len = ZipFile.this.res.zsrc.readFullyAt(loc, 0, loc.length, pos);
                if (len != LOCHDR) {
                    throw new ZipException("ZipFile error reading zip file");
                }
                if (LOCSIG(loc) != LOCSIG) {
                    throw new ZipException("ZipFile invalid LOC header (bad signature)");
                }
                pos += LOCHDR + LOCNAM(loc) + LOCEXT(loc);
            }
            return pos;
        }

        public int read(byte b[], int off, int len) throws IOException {
            synchronized (ZipFile.this) {
                ensureOpenOrZipException();
                initDataOffset();
                if (rem == 0) {
                    return -1;
                }
                if (len > rem) {
                    len = (int) rem;
                }
                if (len <= 0) {
                    return 0;
                }
                len = ZipFile.this.res.zsrc.readAt(b, off, len, pos);
                if (len > 0) {
                    pos += len;
                    rem -= len;
                }
            }
            if (rem == 0) {
                close();
            }
            return len;
        }

        public int read() throws IOException {
            byte[] b = new byte[1];
            if (read(b, 0, 1) == 1) {
                return b[0] & 0xff;
            } else {
                return -1;
            }
        }

        public long skip(long n) throws IOException {
            synchronized (ZipFile.this) {
                initDataOffset();
                if (n > rem) {
                    n = rem;
                }
                pos += n;
                rem -= n;
            }
            if (rem == 0) {
                close();
            }
            return n;
        }

        public int available() {
            return rem > Integer.MAX_VALUE ? Integer.MAX_VALUE : (int) rem;
        }

        public long size() {
            return size;
        }

        public void close() {
            if (closeRequested) {
                return;
            }
            closeRequested = true;
            rem = 0;
            synchronized (res.istreams) {
                res.istreams.remove(this);
            }
        }

    }

    
Returns the names of all non-directory entries that begin with
"META-INF/" (case ignored). This method is used in JarFile, via
SharedSecrets, as an optimization when looking up manifest and
signature file entries. Returns null if no entries were found.

/**
     * Returns the names of all non-directory entries that begin with
     * "META-INF/" (case ignored). This method is used in JarFile, via
     * SharedSecrets, as an optimization when looking up manifest and
     * signature file entries. Returns null if no entries were found.
     */
    private String[] getMetaInfEntryNames() {
        synchronized (this) {
            ensureOpen();
            Source zsrc = res.zsrc;
            if (zsrc.metanames == null) {
                return null;
            }
            String[] names = new String[zsrc.metanames.length];
            byte[] cen = zsrc.cen;
            for (int i = 0; i < names.length; i++) {
                int pos = zsrc.metanames[i];
                names[i] = new String(cen, pos + CENHDR, CENNAM(cen, pos),
                                      StandardCharsets.UTF_8);
            }
            return names;
        }
    }

    private static boolean isWindows;
    static {
        SharedSecrets.setJavaUtilZipFileAccess(
            new JavaUtilZipFileAccess() {
                @Override
                public boolean startsWithLocHeader(ZipFile zip) {
                    return zip.res.zsrc.startsWithLoc;
                }
                @Override
                public String[] getMetaInfEntryNames(ZipFile zip) {
                    return zip.getMetaInfEntryNames();
                }
                @Override
                public JarEntry getEntry(ZipFile zip, String name,
                    Function<String, JarEntry> func) {
                    return (JarEntry)zip.getEntry(name, func);
                }
                @Override
                public Enumeration<JarEntry> entries(ZipFile zip,
                    Function<String, JarEntry> func) {
                    return zip.entries(func);
                }
                @Override
                public Stream<JarEntry> stream(ZipFile zip,
                    Function<String, JarEntry> func) {
                    return zip.stream(func);
                }
                @Override
                public Stream<String> entryNameStream(ZipFile zip) {
                    return zip.entryNameStream();
                }
             }
        );
        isWindows = VM.getSavedProperty("os.name").contains("Windows");
    }

    private static class Source {
        private final Key key;               // the key in files
        private int refs = 1;

        private RandomAccessFile zfile;      // zfile of the underlying zip file
        private byte[] cen;                  // CEN & ENDHDR
        private long locpos;                 // position of first LOC header (usually 0)
        private byte[] comment;              // zip file comment
                                             // list of meta entries in META-INF dir
        private int[] metanames;
        private final boolean startsWithLoc; // true, if zip file starts with LOCSIG (usually true)

        // A Hashmap for all entries.
        //
        // A cen entry of Zip/JAR file. As we have one for every entry in every active Zip/JAR,
        // We might have a lot of these in a typical system. In order to save space we don't
        // keep the name in memory, but merely remember a 32 bit {@code hash} value of the
        // entry name and its offset {@code pos} in the central directory hdeader.
        //
        // private static class Entry {
        //     int hash;       // 32 bit hashcode on name
        //     int next;       // hash chain: index into entries
        //     int pos;        // Offset of central directory file header
        // }
        // private Entry[] entries;             // array of hashed cen entry
        //
        // To reduce the total size of entries further, we use a int[] here to store 3 "int"
        // {@code hash}, {@code next and {@code "pos for each entry. The entry can then be
        // referred by their index of their positions in the {@code entries}.
        //
        private int[] entries;                  // array of hashed cen entry
        private int addEntry(int index, int hash, int next, int pos) {
            entries[index++] = hash;
            entries[index++] = next;
            entries[index++] = pos;
            return index;
        }
        private int getEntryHash(int index) { return entries[index]; }
        private int getEntryNext(int index) { return entries[index + 1]; }
        private int getEntryPos(int index)  { return entries[index + 2]; }
        private static final int ZIP_ENDCHAIN  = -1;
        private int total;                   // total number of entries
        private int[] table;                 // Hash chain heads: indexes into entries
        private int tablelen;                // number of hash heads

        private static class Key {
            BasicFileAttributes attrs;
            File file;

            public Key(File file, BasicFileAttributes attrs) {
                this.attrs = attrs;
                this.file = file;
            }

            public int hashCode() {
                long t = attrs.lastModifiedTime().toMillis();
                return ((int)(t ^ (t >>> 32))) + file.hashCode();
            }

            public boolean equals(Object obj) {
                if (obj instanceof Key) {
                    Key key = (Key)obj;
                    if (!attrs.lastModifiedTime().equals(key.attrs.lastModifiedTime())) {
                        return false;
                    }
                    Object fk = attrs.fileKey();
                    if (fk != null) {
                        return  fk.equals(key.attrs.fileKey());
                    } else {
                        return file.equals(key.file);
                    }
                }
                return false;
            }
        }
        private static final HashMap<Key, Source> files = new HashMap<>();


        static Source get(File file, boolean toDelete) throws IOException {
            Key key = new Key(file,
                              Files.readAttributes(file.toPath(), BasicFileAttributes.class));
            Source src = null;
            synchronized (files) {
                src = files.get(key);
                if (src != null) {
                    src.refs++;
                    return src;
                }
            }
            src = new Source(key, toDelete);

            synchronized (files) {
                if (files.containsKey(key)) {    // someone else put in first
                    src.close();                 // close the newly created one
                    src = files.get(key);
                    src.refs++;
                    return src;
                }
                files.put(key, src);
                return src;
            }
        }

        static void release(Source src) throws IOException {
            synchronized (files) {
                if (src != null && --src.refs == 0) {
                    files.remove(src.key);
                    src.close();
                }
            }
        }

        private Source(Key key, boolean toDelete) throws IOException {
            this.key = key;
            if (toDelete) {
                if (isWindows) {
                    this.zfile = SharedSecrets.getJavaIORandomAccessFileAccess()
                                              .openAndDelete(key.file, "r");
                } else {
                    this.zfile = new RandomAccessFile(key.file, "r");
                    key.file.delete();
                }
            } else {
                this.zfile = new RandomAccessFile(key.file, "r");
            }
            try {
                initCEN(-1);
                byte[] buf = new byte[4];
                readFullyAt(buf, 0, 4, 0);
                this.startsWithLoc = (LOCSIG(buf) == LOCSIG);
            } catch (IOException x) {
                try {
                    this.zfile.close();
                } catch (IOException xx) {}
                throw x;
            }
        }

        private void close() throws IOException {
            zfile.close();
            zfile = null;
            cen = null;
            entries = null;
            table = null;
            metanames = null;
        }

        private static final int BUF_SIZE = 8192;
        private final int readFullyAt(byte[] buf, int off, int len, long pos)
            throws IOException
        {
            synchronized(zfile) {
                zfile.seek(pos);
                int N = len;
                while (N > 0) {
                    int n = Math.min(BUF_SIZE, N);
                    zfile.readFully(buf, off, n);
                    off += n;
                    N -= n;
                }
                return len;
            }
        }

        private final int readAt(byte[] buf, int off, int len, long pos)
            throws IOException
        {
            synchronized(zfile) {
                zfile.seek(pos);
                return zfile.read(buf, off, len);
            }
        }

        private static final int hashN(byte[] a, int off, int len) {
            int h = 1;
            while (len-- > 0) {
                h = 31 * h + a[off++];
            }
            return h;
        }

        private static final int hash_append(int hash, byte b) {
            return hash * 31 + b;
        }

        private static class End {
            int  centot;     // 4 bytes
            long cenlen;     // 4 bytes
            long cenoff;     // 4 bytes
            long endpos;     // 4 bytes
        }

        /*
         * Searches for end of central directory (END) header. The contents of
         * the END header will be read and placed in endbuf. Returns the file
         * position of the END header, otherwise returns -1 if the END header
         * was not found or an error occurred.
         */
        private End findEND() throws IOException {
            long ziplen = zfile.length();
            if (ziplen <= 0)
                zerror("zip file is empty");
            End end = new End();
            byte[] buf = new byte[READBLOCKSZ];
            long minHDR = (ziplen - END_MAXLEN) > 0 ? ziplen - END_MAXLEN : 0;
            long minPos = minHDR - (buf.length - ENDHDR);
            for (long pos = ziplen - buf.length; pos >= minPos; pos -= (buf.length - ENDHDR)) {
                int off = 0;
                if (pos < 0) {
                    // Pretend there are some NUL bytes before start of file
                    off = (int)-pos;
                    Arrays.fill(buf, 0, off, (byte)0);
                }
                int len = buf.length - off;
                if (readFullyAt(buf, off, len, pos + off) != len ) {
                    zerror("zip END header not found");
                }
                // Now scan the block backwards for END header signature
                for (int i = buf.length - ENDHDR; i >= 0; i--) {
                    if (buf[i+0] == (byte)'P'    &&
                        buf[i+1] == (byte)'K'    &&
                        buf[i+2] == (byte)'\005' &&
                        buf[i+3] == (byte)'\006') {
                        // Found ENDSIG header
                        byte[] endbuf = Arrays.copyOfRange(buf, i, i + ENDHDR);
                        end.centot = ENDTOT(endbuf);
                        end.cenlen = ENDSIZ(endbuf);
                        end.cenoff = ENDOFF(endbuf);
                        end.endpos = pos + i;
                        int comlen = ENDCOM(endbuf);
                        if (end.endpos + ENDHDR + comlen != ziplen) {
                            // ENDSIG matched, however the size of file comment in it does
                            // not match the real size. One "common" cause for this problem
                            // is some "extra" bytes are padded at the end of the zipfile.
                            // Let's do some extra verification, we don't care about the
                            // performance in this situation.
                            byte[] sbuf = new byte[4];
                            long cenpos = end.endpos - end.cenlen;
                            long locpos = cenpos - end.cenoff;
                            if  (cenpos < 0 ||
                                 locpos < 0 ||
                                 readFullyAt(sbuf, 0, sbuf.length, cenpos) != 4 ||
                                 GETSIG(sbuf) != CENSIG ||
                                 readFullyAt(sbuf, 0, sbuf.length, locpos) != 4 ||
                                 GETSIG(sbuf) != LOCSIG) {
                                continue;
                            }
                        }
                        if (comlen > 0) {    // this zip file has comlen
                            comment = new byte[comlen];
                            if (readFullyAt(comment, 0, comlen, end.endpos + ENDHDR) != comlen) {
                                zerror("zip comment read failed");
                            }
                        }
                        // must check for a zip64 end record; it is always permitted to be present
                        try {
                            byte[] loc64 = new byte[ZIP64_LOCHDR];
                            if (end.endpos < ZIP64_LOCHDR ||
                                readFullyAt(loc64, 0, loc64.length, end.endpos - ZIP64_LOCHDR)
                                != loc64.length || GETSIG(loc64) != ZIP64_LOCSIG) {
                                return end;
                            }
                            long end64pos = ZIP64_LOCOFF(loc64);
                            byte[] end64buf = new byte[ZIP64_ENDHDR];
                            if (readFullyAt(end64buf, 0, end64buf.length, end64pos)
                                != end64buf.length || GETSIG(end64buf) != ZIP64_ENDSIG) {
                                return end;
                            }
                            // end64 candidate found,
                            long cenlen64 = ZIP64_ENDSIZ(end64buf);
                            long cenoff64 = ZIP64_ENDOFF(end64buf);
                            long centot64 = ZIP64_ENDTOT(end64buf);
                            // double-check
                            if (cenlen64 != end.cenlen && end.cenlen != ZIP64_MAGICVAL ||
                                cenoff64 != end.cenoff && end.cenoff != ZIP64_MAGICVAL ||
                                centot64 != end.centot && end.centot != ZIP64_MAGICCOUNT) {
                                return end;
                            }
                            // to use the end64 values
                            end.cenlen = cenlen64;
                            end.cenoff = cenoff64;
                            end.centot = (int)centot64; // assume total < 2g
                            end.endpos = end64pos;
                        } catch (IOException x) {}    // no zip64 loc/end
                        return end;
                    }
                }
            }
            zerror("zip END header not found");
            return null; //make compiler happy
        }

        // Reads zip file central directory.
        private void initCEN(int knownTotal) throws IOException {
            if (knownTotal == -1) {
                End end = findEND();
                if (end.endpos == 0) {
                    locpos = 0;
                    total = 0;
                    entries  = new int[0];
                    cen = null;
                    return;         // only END header present
                }
                if (end.cenlen > end.endpos)
                    zerror("invalid END header (bad central directory size)");
                long cenpos = end.endpos - end.cenlen;     // position of CEN table
                // Get position of first local file (LOC) header, taking into
                // account that there may be a stub prefixed to the zip file.
                locpos = cenpos - end.cenoff;
                if (locpos < 0) {
                    zerror("invalid END header (bad central directory offset)");
                }
                // read in the CEN and END
                cen = new byte[(int)(end.cenlen + ENDHDR)];
                if (readFullyAt(cen, 0, cen.length, cenpos) != end.cenlen + ENDHDR) {
                    zerror("read CEN tables failed");
                }
                total = end.centot;
            } else {
                total = knownTotal;
            }
            // hash table for entries
            entries  = new int[total * 3];
            tablelen = ((total/2) | 1); // Odd -> fewer collisions
            table    =  new int[tablelen];
            Arrays.fill(table, ZIP_ENDCHAIN);
            int idx = 0;
            int hash = 0;
            int next = -1;

            // list for all meta entries
            ArrayList<Integer> metanamesList = null;

            // Iterate through the entries in the central directory
            int i = 0;
            int hsh = 0;
            int pos = 0;
            int limit = cen.length - ENDHDR;
            while (pos + CENHDR  <= limit) {
                if (i >= total) {
                    // This will only happen if the zip file has an incorrect
                    // ENDTOT field, which usually means it contains more than
                    // 65535 entries.
                    initCEN(countCENHeaders(cen, limit));
                    return;
                }
                if (CENSIG(cen, pos) != CENSIG)
                    zerror("invalid CEN header (bad signature)");
                int method = CENHOW(cen, pos);
                int nlen   = CENNAM(cen, pos);
                int elen   = CENEXT(cen, pos);
                int clen   = CENCOM(cen, pos);
                if ((CENFLG(cen, pos) & 1) != 0)
                    zerror("invalid CEN header (encrypted entry)");
                if (method != STORED && method != DEFLATED)
                    zerror("invalid CEN header (bad compression method: " + method + ")");
                if (pos + CENHDR + nlen > limit)
                    zerror("invalid CEN header (bad header size)");
                // Record the CEN offset and the name hash in our hash cell.
                hash = hashN(cen, pos + CENHDR, nlen);
                hsh = (hash & 0x7fffffff) % tablelen;
                next = table[hsh];
                table[hsh] = idx;
                idx = addEntry(idx, hash, next, pos);
                // Adds name to metanames.
                if (isMetaName(cen, pos + CENHDR, nlen)) {
                    if (metanamesList == null)
                        metanamesList = new ArrayList<>(4);
                    metanamesList.add(pos);
                }
                // skip ext and comment
                pos += (CENHDR + nlen + elen + clen);
                i++;
            }
            total = i;
            if (metanamesList != null) {
                metanames = new int[metanamesList.size()];
                for (int j = 0, len = metanames.length; j < len; j++) {
                    metanames[j] = metanamesList.get(j);
                }
            }
            if (pos + ENDHDR != cen.length) {
                zerror("invalid CEN header (bad header size)");
            }
        }

        private static void zerror(String msg) throws ZipException {
            throw new ZipException(msg);
        }

        /*
         * Returns the {@code pos} of the zip cen entry corresponding to the
         * specified entry name, or -1 if not found.
         */
        private int getEntryPos(byte[] name, boolean addSlash) {
            if (total == 0) {
                return -1;
            }
            int hsh = hashN(name, 0, name.length);
            int idx = table[(hsh & 0x7fffffff) % tablelen];
            /*
             * This while loop is an optimization where a double lookup
             * for name and name+/ is being performed. The name char
             * array has enough room at the end to try again with a
             * slash appended if the first table lookup does not succeed.
             */
            while(true) {
                /*
                 * Search down the target hash chain for a entry whose
                 * 32 bit hash matches the hashed name.
                 */
                while (idx != ZIP_ENDCHAIN) {
                    if (getEntryHash(idx) == hsh) {
                        // The CEN name must match the specfied one
                        int pos = getEntryPos(idx);
                        if (name.length == CENNAM(cen, pos)) {
                            boolean matched = true;
                            int nameoff = pos + CENHDR;
                            for (int i = 0; i < name.length; i++) {
                                if (name[i] != cen[nameoff++]) {
                                    matched = false;
                                    break;
                                }
                            }
                            if (matched) {
                                return pos;
                            }
                         }
                    }
                    idx = getEntryNext(idx);
                }
                /* If not addSlash, or slash is already there, we are done */
                if (!addSlash  || name.length == 0 || name[name.length - 1] == '/') {
                     return -1;
                }
                /* Add slash and try once more */
                name = Arrays.copyOf(name, name.length + 1);
                name[name.length - 1] = '/';
                hsh = hash_append(hsh, (byte)'/');
                //idx = table[hsh % tablelen];
                idx = table[(hsh & 0x7fffffff) % tablelen];
                addSlash = false;
            }
        }

        
Returns true if the bytes represent a non-directory name
beginning with "META-INF/", disregarding ASCII case.

/**
         * Returns true if the bytes represent a non-directory name
         * beginning with "META-INF/", disregarding ASCII case.
         */
        private static boolean isMetaName(byte[] name, int off, int len) {
            // Use the "oldest ASCII trick in the book"
            return len > 9                     // "META-INF/".length()
                && name[off + len - 1] != '/'  // non-directory
                && (name[off++] | 0x20) == 'm'
                && (name[off++] | 0x20) == 'e'
                && (name[off++] | 0x20) == 't'
                && (name[off++] | 0x20) == 'a'
                && (name[off++]       ) == '-'
                && (name[off++] | 0x20) == 'i'
                && (name[off++] | 0x20) == 'n'
                && (name[off++] | 0x20) == 'f'
                && (name[off]         ) == '/';
        }

        
Returns the number of CEN headers in a central directory.
Will not throw, even if the zip file is corrupt.

Params:
  • cen – copy of the bytes in a zip file's central directory
  • size – number of bytes in central directory
/**
         * Returns the number of CEN headers in a central directory.
         * Will not throw, even if the zip file is corrupt.
         *
         * @param cen copy of the bytes in a zip file's central directory
         * @param size number of bytes in central directory
         */
        private static int countCENHeaders(byte[] cen, int size) {
            int count = 0;
            for (int p = 0;
                 p + CENHDR <= size;
                 p += CENHDR + CENNAM(cen, p) + CENEXT(cen, p) + CENCOM(cen, p))
                count++;
            return count;
        }
    }
}