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 * 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
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 * accompanied this code).
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package java.util.zip;

import java.io.InputStream;
import java.io.IOException;
import java.io.EOFException;
import java.io.File;
import java.util.Vector;
import java.util.Enumeration;
import java.util.NoSuchElementException;


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
/**
 * This class is used to read entries from a zip file.
 *
 * <p> Unless otherwise noted, passing a <tt>null</tt> argument to a constructor
 * or method in this class will cause a {@link NullPointerException} to be
 * thrown.
 *
 * @author      David Connelly
 */
public
class ZipFile implements ZipConstants {
    private long jzfile;           // address of jzfile data
    private final String name;     // zip file name
    private final int total;       // total number of entries
    private final boolean locsig;  // if zip file starts with LOCSIG (usually true)
    private boolean closeRequested;

    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
     * <tt>ZipFile</tt> object until either the close method is invoked or the
     * virtual machine exits.
     */
    public static final int OPEN_DELETE = 0x4;

    static {
        /* Zip library is loaded from System.initializeSystemClass */
        initIDs();
    }

    private static native void initIDs();

    
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
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</code> method
     * is called with the <code>name</code> argument
     * as its argument to ensure the read is allowed.
     *
     * @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</code> 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.

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</code> to read from the specified
     * <code>File</code> object in the specified mode.  The mode argument
     * must be either <tt>OPEN_READ</tt> or <tt>OPEN_READ | OPEN_DELETE</tt>.
     *
     * <p>First, if there is a security manager, its <code>checkRead</code>
     * method is called with the <code>name</code> 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
     * @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</code> method
     *         doesn't allow read access to the file,
     *         or its <code>checkDelete</code> method doesn't allow deleting
     *         the file when the <tt>OPEN_DELETE</tt> flag is set.
     * @throws IllegalArgumentException if the <tt>mode</tt> argument is invalid
     * @see SecurityManager#checkRead(java.lang.String)
     * @since 1.3
     */
    public ZipFile(File file, int mode) 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);
            }
        }
        jzfile = open(name, mode, file.lastModified());

        this.name = name;
        this.total = getTotal(jzfile);
        this.locsig = startsWithLOC(jzfile);
    }

    static {
        sun.misc.SharedSecrets.setJavaUtilZipFileAccess(
            new sun.misc.JavaUtilZipFileAccess() {
                public boolean startsWithLocHeader(ZipFile zip) {
                    return zip.startsWithLocHeader();
                }
             }
        );
    }

    
Returns true if, and only if, the zip file begins with 
LOCSIG. 
/**
     * Returns {@code true} if, and only if, the zip file begins with {@code
     * LOCSIG}.
     */
    private boolean startsWithLocHeader() {
        return locsig;
    }

    private static native long open(String name, int mode, long lastModified);
    private static native int getTotal(long jzfile);
    private static native boolean startsWithLOC(long jzfile);


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

Params:
  • file – the ZIP file to be opened for reading
Throws:
/**
     * Opens a ZIP file for reading given the specified File object.
     * @param file the ZIP file to be opened for reading
     * @throws ZipException if a ZIP error has occurred
     * @throws IOException if an I/O error has occurred
     */
    public ZipFile(File file) throws ZipException, IOException {
        this(file, OPEN_READ);
    }

    
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) {
        if (name == null) {
            throw new NullPointerException("name");
        }
        long jzentry = 0;
        synchronized (this) {
            ensureOpen();
            jzentry = getEntry(jzfile, name, true);
            if (jzentry != 0) {
                ZipEntry ze = new ZipEntry(name, jzentry);
                freeEntry(jzfile, jzentry);
                return ze;
            }
        }
        return null;
    }

    private static native long getEntry(long jzfile, String name,
                                        boolean addSlash);

    // freeEntry releases the C jzentry struct.
    private static native void freeEntry(long jzfile, long jzentry);

    
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 {
        return getInputStream(entry.name);
    }

    
Returns an input stream for reading the contents of the specified
entry, or null if the entry was not found.

/**
     * Returns an input stream for reading the contents of the specified
     * entry, or null if the entry was not found.
     */
    private InputStream getInputStream(String name) throws IOException {
        if (name == null) {
            throw new NullPointerException("name");
        }
        long jzentry = 0;
        ZipFileInputStream in = null;
        synchronized (this) {
            ensureOpen();
            jzentry = getEntry(jzfile, name, false);
            if (jzentry == 0) {
                return null;
            }

            in = new ZipFileInputStream(jzentry);

        }
        final ZipFileInputStream zfin = in;
        switch (getMethod(jzentry)) {
        case STORED:
            return zfin;
        case DEFLATED:
            // MORE: Compute good size for inflater stream:
            long size = getSize(jzentry) + 2; // Inflater likes a bit of slack
            if (size > 65536) size = 8192;
            if (size <= 0) size = 4096;
            return new InflaterInputStream(zfin, getInflater(), (int)size) {
                private boolean isClosed = false;

                public void close() throws IOException {
                    if (!isClosed) {
                         releaseInflater(inf);
                        this.in.close();
                        isClosed = true;
                    }
                }
                // 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 = this.in.read(buf, 0, buf.length);
                    if (len == -1) {
                        buf[0] = 0;
                        len = 1;
                        eof = true;
                    }
                    inf.setInput(buf, 0, len);
                }
                private boolean eof;

                public int available() throws IOException {
                    if (isClosed)
                        return 0;
                    long avail = zfin.size() - inf.getBytesWritten();
                    return avail > (long) Integer.MAX_VALUE ?
                        Integer.MAX_VALUE : (int) avail;
                }
            };
        default:
            throw new ZipException("invalid compression method");
        }
    }

    private static native int getMethod(long jzentry);

    /*
     * Gets an inflater from the list of available inflaters or allocates
     * a new one.
     */
    private Inflater getInflater() {
        synchronized (inflaters) {
            int size = inflaters.size();
            if (size > 0) {
                Inflater inf = (Inflater)inflaters.remove(size - 1);
                inf.reset();
                return inf;
            } else {
                return new Inflater(true);
            }
        }
    }

    /*
     * Releases the specified inflater to the list of available inflaters.
     */
    private void releaseInflater(Inflater inf) {
        synchronized (inflaters) {
            inflaters.add(inf);
        }
    }

    // List of available Inflater objects for decompression
    private Vector inflaters = new Vector();

    
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;
    }

    
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() {
        ensureOpen();
        return new Enumeration<ZipEntry>() {
                private int i = 0;
                public boolean hasMoreElements() {
                    synchronized (ZipFile.this) {
                        ensureOpen();
                        return i < total;
                    }
                }
                public ZipEntry nextElement() throws NoSuchElementException {
                    synchronized (ZipFile.this) {
                        ensureOpen();
                        if (i >= total) {
                            throw new NoSuchElementException();
                        }
                        long jzentry = getNextEntry(jzfile, i++);
                        if (jzentry == 0) {
                            String message;
                            if (closeRequested) {
                                message = "ZipFile concurrently closed";
                            } else {
                                message = getZipMessage(ZipFile.this.jzfile);
                            }
                            throw new ZipError("jzentry == 0" +
                                               ",\n jzfile = " + ZipFile.this.jzfile +
                                               ",\n total = " + ZipFile.this.total +
                                               ",\n name = " + ZipFile.this.name +
                                               ",\n i = " + i +
                                               ",\n message = " + message
                                );
                        }
                        ZipEntry ze = new ZipEntry(jzentry);
                        freeEntry(jzfile, jzentry);
                        return ze;
                    }
                }
            };
    }

    private static native long getNextEntry(long jzfile, int i);

    
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() {
        ensureOpen();
        return total;
    }

    
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 {
        synchronized (this) {
            closeRequested = true;

            if (jzfile != 0) {
                // Close the zip file
                long zf = this.jzfile;
                jzfile = 0;

                close(zf);

                // Release inflaters
                synchronized (inflaters) {
                    int size = inflaters.size();
                    for (int i = 0; i < size; i++) {
                        Inflater inf = (Inflater)inflaters.get(i);
                        inf.end();
                    }
                }
            }
        }
    }


    
Ensures that the close method of this ZIP file is
called when there are no more references to it.


Since the time when GC would invoke this method is undetermined,
it is strongly recommended that applications invoke the close
method as soon they have finished accessing this ZipFile.
This will prevent holding up system resources for an undetermined
length of time.

Throws:
  • IOException – if an I/O error has occurred
See Also:
/**
     * Ensures that the <code>close</code> method of this ZIP file is
     * called when there are no more references to it.
     *
     * <p>
     * Since the time when GC would invoke this method is undetermined,
     * it is strongly recommended that applications invoke the <code>close</code>
     * method as soon they have finished accessing this <code>ZipFile</code>.
     * This will prevent holding up system resources for an undetermined
     * length of time.
     *
     * @throws IOException if an I/O error has occurred
     * @see    java.util.zip.ZipFile#close()
     */
    protected void finalize() throws IOException {
        close();
    }

    private static native void close(long jzfile);

    private void ensureOpen() {
        if (closeRequested) {
            throw new IllegalStateException("zip file closed");
        }

        if (jzfile == 0) {
            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 {
        protected long jzentry; // address of jzentry data
        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(long jzentry) {
            pos = 0;
            rem = getCSize(jzentry);
            size = getSize(jzentry);
            this.jzentry = jzentry;
        }

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

                len = ZipFile.read(ZipFile.this.jzfile, jzentry, pos, b,
                                   off, len);
            }
            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) {
            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() {
            rem = 0;
            synchronized (ZipFile.this) {
                if (jzentry != 0 && ZipFile.this.jzfile != 0) {
                    freeEntry(ZipFile.this.jzfile, jzentry);
                    jzentry = 0;
                }
            }
        }

    }

    private static native int read(long jzfile, long jzentry,
                                   long pos, byte[] b, int off, int len);

    private static native long getCSize(long jzentry);

    private static native long getSize(long jzentry);

    // Temporary add on for bug troubleshooting
    private static native String getZipMessage(long jzfile);
}