zipfile.java

来自「纯java操作系统jnode,安装简单和操作简单的个人使用的Java操作系统」· Java 代码 · 共 661 行 · 第 1/2 页

/* java.util.zip.ZipFile
   Copyright (C) 2001, 2002, 2003 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Classpath 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 for more details.

You should have received a copy of the GNU General Public License
along with GNU Classpath; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.

As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under
terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
module.  An independent module is a module which is not derived from
or based on this library.  If you modify this library, you may extend
this exception to your version of the library, but you are not
obligated to do so.  If you do not wish to do so, delete this
exception statement from your version. */

package java.util.zip;

import java.io.BufferedInputStream;
import java.io.EOFException;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.NoSuchElementException;

/**
 * This class represents a Zip archive.  You can ask for the contained
 * entries, or get an input stream for a file entry.  The entry is
 * automatically decompressed.
 *
 * This class is thread safe:  You can open input streams for arbitrary
 * entries in different threads.
 *
 * @author Jochen Hoenicke
 * @author Artur Biesiadowski
 */
public class ZipFile implements ZipConstants {

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

	/**
	 * Mode flag to delete a zip file after reading.
	 */
	public static final int OPEN_DELETE = 0x4;

	// Name of this zip file.
	private final String name;

	// File from which zip entries are read.
	private final RandomAccessBuffer raf;

	// The entries of this zip file when initialized and not yet closed.
	private HashMap entries;

	private boolean closed = false;

	/**
	 * Opens a Zip file with the given name for reading.
	 * @exception IOException if a i/o error occured.
	 * @exception ZipException if the file doesn't contain a valid zip
	 * archive.  
	 */
	public ZipFile(RandomAccessBuffer raf, String name) throws ZipException, IOException {
		this.raf = raf;
		this.name = name;
	}

	/**
	 * Opens a Zip file with the given name for reading.
	 * @exception IOException if a i/o error occured.
	 * @exception ZipException if the file doesn't contain a valid zip
	 * archive.  
	 */
	public ZipFile(String name) throws ZipException, IOException {
		this(new RandomAccessFileBuffer(new RandomAccessFile(name, "r")), name);
	}

	/**
	 * Opens a Zip file reading the given File.
	 * @exception IOException if a i/o error occured.
	 * @exception ZipException if the file doesn't contain a valid zip
	 * archive.  
	 */
	public ZipFile(File file) throws ZipException, IOException {
		this(new RandomAccessFileBuffer(new RandomAccessFile(file, "r")), file.getName());
	}

	/**
	 * Opens a Zip file reading the given byte array.
	 * @exception IOException if a i/o error occured.
	 * @exception ZipException if the file doesn't contain a valid zip
	 * archive.  
	 */
	public ZipFile(byte[] data) throws ZipException, IOException {
		this(new RandomAccessByteArrayBuffer(data), "byte array");
	}

	/**
	 * Opens a Zip file reading the given File in the given mode.
	 *
	 * If the OPEN_DELETE mode is specified, the zip file will be deleted at
	 * some time moment after it is opened. It will be deleted before the zip
	 * file is closed or the Virtual Machine exits.
	 * 
	 * The contents of the zip file will be accessible until it is closed.
	 *
	 * The OPEN_DELETE mode is currently unimplemented in this library
	 * 
	 * @since JDK1.3
	 * @param mode Must be one of OPEN_READ or OPEN_READ | OPEN_DELETE
	 *
	 * @exception IOException if a i/o error occured.
	 * @exception ZipException if the file doesn't contain a valid zip
	 * archive.  
	 */
	public ZipFile(File file, int mode) throws ZipException, IOException {
		if ((mode & OPEN_DELETE) != 0) {
			throw new IllegalArgumentException("OPEN_DELETE mode not supported yet in java.util.zip.ZipFile");
		}
		this.raf = new RandomAccessFileBuffer(new RandomAccessFile(file, "r"));
		this.name = file.getName();
	}

	/**
	 * Read an unsigned short in little endian byte order from the given
	 * DataInput stream using the given byte buffer.
	 *
	 * @param di DataInput stream to read from.
	 * @param b the byte buffer to read in (must be at least 2 bytes long).
	 * @return The value read.
	 *
	 * @exception IOException if a i/o error occured.
	 * @exception EOFException if the file ends prematurely
	 */
	private final int readLeShort(RandomAccessBuffer di, byte[] b) throws IOException {
		di.readFully(b, 0, 2);
		return (b[0] & 0xff) | (b[1] & 0xff) << 8;
	}

	/**
	 * Read an int in little endian byte order from the given
	 * DataInput stream using the given byte buffer.
	 *
	 * @param di DataInput stream to read from.
	 * @param b the byte buffer to read in (must be at least 4 bytes long).
	 * @return The value read.
	 *
	 * @exception IOException if a i/o error occured.
	 * @exception EOFException if the file ends prematurely
	 */
	private final int readLeInt(RandomAccessBuffer di, byte[] b) throws IOException {
		di.readFully(b, 0, 4);
		return ((b[0] & 0xff) | (b[1] & 0xff) << 8) | ((b[2] & 0xff) | (b[3] & 0xff) << 8) << 16;
	}

	/**
	 * Read an unsigned short in little endian byte order from the given
	 * byte buffer at the given offset.
	 *
	 * @param b the byte array to read from.
	 * @param off the offset to read from.
	 * @return The value read.
	 */
	private final int readLeShort(byte[] b, int off) {
		return (b[off] & 0xff) | (b[off + 1] & 0xff) << 8;
	}

	/**
	 * Read an int in little endian byte order from the given
	 * byte buffer at the given offset.
	 *
	 * @param b the byte array to read from.
	 * @param off the offset to read from.
	 * @return The value read.
	 */
	private final int readLeInt(byte[] b, int off) {
		return ((b[off] & 0xff) | (b[off + 1] & 0xff) << 8) | ((b[off + 2] & 0xff) | (b[off + 3] & 0xff) << 8) << 16;
	}

	/**
	 * Read the central directory of a zip file and fill the entries
	 * array.  This is called exactly once when first needed. It is called
	 * while holding the lock on <code>raf</code>.
	 *
	 * @exception IOException if a i/o error occured.
	 * @exception ZipException if the central directory is malformed 
	 */
	private void readEntries() throws ZipException, IOException {
		/* Search for the End Of Central Directory.  When a zip comment is 
		 * present the directory may start earlier.
		 * FIXME: This searches the whole file in a very slow manner if the
		 * file isn't a zip file.
		 */
		long pos = raf.length() - ENDHDR;
		byte[] ebs = new byte[CENHDR];

		do {
			if (pos < 0)
				throw new ZipException("central directory not found, probably not a zip file: " + name);
			raf.seek(pos--);
		} while (readLeInt(raf, ebs) != ENDSIG);

		if (raf.skipBytes(ENDTOT - ENDNRD) != ENDTOT - ENDNRD)
			throw new EOFException(name);
		int count = readLeShort(raf, ebs);
		if (raf.skipBytes(ENDOFF - ENDSIZ) != ENDOFF - ENDSIZ)
			throw new EOFException(name);
		int centralOffset = readLeInt(raf, ebs);

		entries = new HashMap(count + count / 2);
		raf.seek(centralOffset);

		byte[] buffer = new byte[16];
		for (int i = 0; i < count; i++) {
			raf.readFully(ebs);
			if (readLeInt(ebs, 0) != CENSIG)
				throw new ZipException("Wrong Central Directory signature: " + name);

			int method = readLeShort(ebs, CENHOW);
			int dostime = readLeInt(ebs, CENTIM);
			int crc = readLeInt(ebs, CENCRC);
			int csize = readLeInt(ebs, CENSIZ);
			int size = readLeInt(ebs, CENLEN);
			int nameLen = readLeShort(ebs, CENNAM);
			int extraLen = readLeShort(ebs, CENEXT);
			int commentLen = readLeShort(ebs, CENCOM);

			int offset = readLeInt(ebs, CENOFF);

			int needBuffer = Math.max(nameLen, commentLen);
			if (buffer.length < needBuffer)
				buffer = new byte[needBuffer];

			raf.readFully(buffer, 0, nameLen);
			String name = new String(buffer, 0, 0, nameLen);

			ZipEntry entry = new ZipEntry(name);
			entry.setMethod(method);
			entry.setCrc(crc & 0xffffffffL);
			entry.setSize(size & 0xffffffffL);
			entry.setCompressedSize(csize & 0xffffffffL);
			entry.setDOSTime(dostime);
			if (extraLen > 0) {
				byte[] extra = new byte[extraLen];
				raf.readFully(extra);
				entry.setExtra(extra);
			}
			if (commentLen > 0) {
				raf.readFully(buffer, 0, commentLen);
				entry.setComment(new String(buffer, 0, commentLen));
			}
			entry.offset = offset;
			entries.put(name, entry);
		}
	}

	/**
	 * Closes the ZipFile.  This also closes all input streams given by
	 * this class.  After this is called, no further method should be
	 * called.
	 * 
	 * @exception IOException if a i/o error occured.
	 */
	public void close() throws IOException {
		synchronized (raf) {
			closed = true;
			entries = null;
			raf.close();
		}
	}

	/**
	 * Returns an enumeration of all Zip entries in this Zip file.
	 */
	public Enumeration entries() {
		try {
			return new ZipEntryEnumeration(getEntries().values().iterator());
		} catch (IOException ioe) {
			return null;
		}
	}

	/**
	 * Checks that the ZipFile is still open and reads entries when necessary.
	 *
	 * @exception IllegalStateException when the ZipFile has already been closed.
	 * @exception IOEexception when the entries could not be read.
	 */
	private HashMap getEntries() throws IOException {
		synchronized (raf) {
			if (closed)
				throw new IllegalStateException("ZipFile has closed: " + name);

			if (entries == null)
				readEntries();

			return entries;
		}
	}

	/**
	 * Searches for a zip entry in this archive with the given name.
	 *