zipfile.java

java源代码 请看看啊 提点宝贵的意见

/*
 * @(#)ZipFile.java	1.60 04/05/06
 *
 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

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;
import java.security.AccessController;

/**
 * This class is used to read entries from a zip file.
 *
 * @version   1.60, 05/06/04 
 * @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 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 {
	AccessController.doPrivileged(
			  new sun.security.action.LoadLibraryAction("zip"));
	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
     * @exception ZipException if a ZIP format error has occurred
     * @exception IOException if an I/O error has occurred
     * @exception  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
     * @exception ZipException if a ZIP format error has occurred
     * @exception IOException if an I/O error has occurred
     * @exception  SecurityException  if a security manager exists and its  
     *             <code>checkRead</code> method doesn't allow read access to the file,
     *             or <code>checkDelete</code> method doesn't allow deleting the file
     *             when <tt>OPEN_DELETE</tt> flag is set.
     * @exception IllegalArgumentException
     *            If the <tt>mode</tt> argument is invalid
     * @see SecurityManager#checkRead(java.lang.String)
     */
    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);
	    }
	}
	long jzfileCopy = open(name, mode, file.lastModified());
	this.name = name;
	this.total = getTotal(jzfileCopy);
        jzfile = jzfileCopy;
    }

    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
     * @exception ZipException if a ZIP error has occurred
     * @exception 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
     * @exception 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(jzfile);
            jzentry = getEntry(jzfile, name);
            if (jzentry == 0 && !name.endsWith("/")) {
                // try a directory name
                jzentry = getEntry(jzfile, name + "/");
            }

            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);

    // 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.
     *
     * 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.
     * @exception ZipException if a ZIP format error has occurred
     * @exception IOException if an I/O error has occurred
     * @exception 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(jzfile);
            jzentry = getEntry(jzfile, name);
            if (jzentry == 0) {
                return null;
            }
            in = new ZipFileInputStream(jzentry, this);
        }
	final ZipFileInputStream zfin = in;
	switch (getMethod(jzentry)) {
	case STORED:
	    return zfin;
	case DEFLATED:
	    return new InflaterInputStream(zfin, getInflater()) {
		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;
		    return zfin.size() - inf.getTotalOut();
		}
	    };
	default:
	    throw new ZipException("invalid compression method");
	}
    }