/*

 * Copyright 1995-2006 Sun Microsystems, Inc.  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.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

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.

 *

 * <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 String name;  // zip file name

    private int total;    // total number of entries

    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.

     */

    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

     * <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.

     *

     * <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 <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);

    }

    private static native long open(String name, int mode, long lastModified);

    private static native int getTotal(long jzfile);

    /**

     * 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.

     *

     * @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.

     *

     * <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.

     */

    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.

     * @return the path name of the ZIP file

     */

    public String getName() {

        return name;

    }

    /**

     * 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.

     * @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.

     * <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 <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);

}