luni/src/main/java/java/util/zip/ZipFile.java - platform/libcore2 - Git at Google

 /*
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
  * The ASF licenses this file to You under the Apache License, Version 2.0
  * (the "License"); you may not use this file except in compliance with
  * the License.  You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 package java.util.zip;

 import dalvik.system.CloseGuard;
 import java.io.BufferedInputStream;
 import java.io.EOFException;
 import java.io.DataInputStream;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.RandomAccessFile;
 import java.nio.ByteOrder;
 import java.util.Enumeration;
 import java.util.Iterator;
 import java.util.LinkedHashMap;
 import libcore.io.BufferIterator;
 import libcore.io.HeapBufferIterator;
 import libcore.io.Streams;

 /**
  * This class provides random read access to a zip file. You pay more to read
  * the zip file's central directory up front (from the constructor), but if you're using
  * {@link #getEntry} to look up multiple files by name, you get the benefit of this index.
  *
  * <p>If you only want to iterate through all the files (using {@link #entries}, you should
  * consider {@link ZipInputStream}, which provides stream-like read access to a zip file and
  * has a lower up-front cost because you don't pay to build an in-memory index.
  *
  * <p>If you want to create a zip file, use {@link ZipOutputStream}. There is no API for updating
  * an existing zip file.
  */
 public class ZipFile implements ZipConstants {
     /**
      * General Purpose Bit Flags, Bit 3.
      * If this bit is set, the fields crc-32, compressed
      * size and uncompressed size are set to zero in the
      * local header.  The correct values are put in the
      * data descriptor immediately following the compressed
      * data.  (Note: PKZIP version 2.04g for DOS only
      * recognizes this bit for method 8 compression, newer
      * versions of PKZIP recognize this bit for any
      * compression method.)
      */
     static final int GPBF_DATA_DESCRIPTOR_FLAG = 1 << 3;

     /**
      * General Purpose Bit Flags, Bit 11.
      * Language encoding flag (EFS).  If this bit is set,
      * the filename and comment fields for this file
      * must be encoded using UTF-8.
      */
     static final int GPBF_UTF8_FLAG = 1 << 11;

     /**
      * Open zip file for reading.
      */
     public static final int OPEN_READ = 1;

     /**
      * Delete zip file when closed.
      */
     public static final int OPEN_DELETE = 4;

     private final String filename;

     private File fileToDeleteOnClose;

     private RandomAccessFile raf;

     private final LinkedHashMap<String, ZipEntry> entries = new LinkedHashMap<String, ZipEntry>();

     private final CloseGuard guard = CloseGuard.get();

     /**
      * Constructs a new {@code ZipFile} allowing read access to the contents of the given file.
      * @throws ZipException if a zip error occurs.
      * @throws IOException if an {@code IOException} occurs.
      */
     public ZipFile(File file) throws ZipException, IOException {
         this(file, OPEN_READ);
     }

     /**
      * Constructs a new {@code ZipFile} allowing read access to the contents of the given file.
      * @throws IOException if an IOException occurs.
      */
     public ZipFile(String name) throws IOException {
         this(new File(name), OPEN_READ);
     }

     /**
      * Constructs a new {@code ZipFile} allowing access to the given file.
      * The {@code mode} must be either {@code OPEN_READ} or {@code OPEN_READ|OPEN_DELETE}.
      *
      * <p>If the {@code OPEN_DELETE} flag is supplied, the file will be deleted at or before the
      * time that the {@code ZipFile} is closed (the contents will remain accessible until
      * this {@code ZipFile} is closed); it also calls {@code File.deleteOnExit}.
      *
      * @throws IOException if an {@code IOException} occurs.
      */
     public ZipFile(File file, int mode) throws IOException {
         filename = file.getPath();
         if (mode != OPEN_READ && mode != (OPEN_READ | OPEN_DELETE)) {
             throw new IllegalArgumentException("Bad mode: " + mode);
         }

         if ((mode & OPEN_DELETE) != 0) {
             fileToDeleteOnClose = file;
             fileToDeleteOnClose.deleteOnExit();
         } else {
             fileToDeleteOnClose = null;
         }

         raf = new RandomAccessFile(filename, "r");

         readCentralDir();
         guard.open("close");
     }

     @Override protected void finalize() throws IOException {
         try {
             if (guard != null) {
                 guard.warnIfOpen();
             }
         } finally {
             try {
                 super.finalize();
             } catch (Throwable t) {
                 throw new AssertionError(t);
             }
         }
     }

     /**
      * Closes this zip file. This method is idempotent. This method may cause I/O if the
      * zip file needs to be deleted.
      *
      * @throws IOException
      *             if an IOException occurs.
      */
     public void close() throws IOException {
         guard.close();

         RandomAccessFile localRaf = raf;
         if (localRaf != null) { // Only close initialized instances
             synchronized (localRaf) {
                 raf = null;
                 localRaf.close();
             }
             if (fileToDeleteOnClose != null) {
                 fileToDeleteOnClose.delete();
                 fileToDeleteOnClose = null;
             }
         }
     }

     private void checkNotClosed() {
         if (raf == null) {
             throw new IllegalStateException("Zip file closed");
         }
     }

     /**
      * Returns an enumeration of the entries. The entries are listed in the
      * order in which they appear in the zip file.
      *
      * <p>If you only need to iterate over the entries in a zip file, and don't
      * need random-access entry lookup by name, you should probably use {@link ZipInputStream}
      * instead, to avoid paying to construct the in-memory index.
      *
      * @throws IllegalStateException if this zip file has been closed.
      */
     public Enumeration<? extends ZipEntry> entries() {
         checkNotClosed();
         final Iterator<ZipEntry> iterator = entries.values().iterator();

         return new Enumeration<ZipEntry>() {
             public boolean hasMoreElements() {
                 checkNotClosed();
                 return iterator.hasNext();
             }

             public ZipEntry nextElement() {
                 checkNotClosed();
                 return iterator.next();
             }
         };
     }

     /**
      * Returns the zip entry with the given name, or null if there is no such entry.
      *
      * @throws IllegalStateException if this zip file has been closed.
      */
     public ZipEntry getEntry(String entryName) {
         checkNotClosed();
         if (entryName == null) {
             throw new NullPointerException("entryName == null");
         }

         ZipEntry ze = entries.get(entryName);
         if (ze == null) {
             ze = entries.get(entryName + "/");
         }
         return ze;
     }

     /**
      * Returns an input stream on the data of the specified {@code ZipEntry}.
      *
      * @param entry
      *            the ZipEntry.
      * @return an input stream of the data contained in the {@code ZipEntry}.
      * @throws IOException
      *             if an {@code IOException} occurs.
      * @throws IllegalStateException if this zip file has been closed.
      */
     public InputStream getInputStream(ZipEntry entry) throws IOException {
         // Make sure this ZipEntry is in this Zip file.  We run it through the name lookup.
         entry = getEntry(entry.getName());
         if (entry == null) {
             return null;
         }

         // Create an InputStream at the right part of the file.
         RandomAccessFile localRaf = raf;
         synchronized (localRaf) {
             // We don't know the entry data's start position. All we have is the
             // position of the entry's local header. At position 28 we find the
             // length of the extra data. In some cases this length differs from
             // the one coming in the central header.
             RAFStream rafStream = new RAFStream(localRaf, entry.localHeaderRelOffset + 28);
             DataInputStream is = new DataInputStream(rafStream);
             int localExtraLenOrWhatever = Short.reverseBytes(is.readShort());
             is.close();

             // Skip the name and this "extra" data or whatever it is:
             rafStream.skip(entry.nameLength + localExtraLenOrWhatever);
             rafStream.length = rafStream.offset + entry.compressedSize;
             if (entry.compressionMethod == ZipEntry.DEFLATED) {
                 int bufSize = Math.max(1024, (int)Math.min(entry.getSize(), 65535L));
                 return new ZipInflaterInputStream(rafStream, new Inflater(true), bufSize, entry);
             } else {
                 return rafStream;
             }
         }
     }

     /**
      * Gets the file name of this {@code ZipFile}.
      *
      * @return the file name of this {@code ZipFile}.
      */
     public String getName() {
         return filename;
     }

     /**
      * Returns the number of {@code ZipEntries} in this {@code ZipFile}.
      *
      * @return the number of entries in this file.
      * @throws IllegalStateException if this zip file has been closed.
      */
     public int size() {
         checkNotClosed();
         return entries.size();
     }

     /**
      * Find the central directory and read the contents.
      *
      * <p>The central directory can be followed by a variable-length comment
      * field, so we have to scan through it backwards.  The comment is at
      * most 64K, plus we have 18 bytes for the end-of-central-dir stuff
      * itself, plus apparently sometimes people throw random junk on the end
      * just for the fun of it.
      *
      * <p>This is all a little wobbly.  If the wrong value ends up in the EOCD
      * area, we're hosed. This appears to be the way that everybody handles
      * it though, so we're in good company if this fails.
      */
     private void readCentralDir() throws IOException {
         // Scan back, looking for the End Of Central Directory field. If the zip file doesn't
         // have an overall comment (unrelated to any per-entry comments), we'll hit the EOCD
         // on the first try.
         // No need to synchronize raf here -- we only do this when we first open the zip file.
         long scanOffset = raf.length() - ENDHDR;
         if (scanOffset < 0) {
             throw new ZipException("File too short to be a zip file: " + raf.length());
         }

         long stopOffset = scanOffset - 65536;
         if (stopOffset < 0) {
             stopOffset = 0;
         }

         final int ENDHEADERMAGIC = 0x06054b50;
         while (true) {
             raf.seek(scanOffset);
             if (Integer.reverseBytes(raf.readInt()) == ENDHEADERMAGIC) {
                 break;
             }

             scanOffset--;
             if (scanOffset < stopOffset) {
                 throw new ZipException("EOCD not found; not a zip file?");
             }
         }

         // Read the End Of Central Directory. We could use ENDHDR instead of the magic number 18,
         // but we don't actually need all the header.
         byte[] eocd = new byte[18];
         raf.readFully(eocd);

         // Pull out the information we need.
         BufferIterator it = HeapBufferIterator.iterator(eocd, 0, eocd.length, ByteOrder.LITTLE_ENDIAN);
         int diskNumber = it.readShort() & 0xffff;
         int diskWithCentralDir = it.readShort() & 0xffff;
         int numEntries = it.readShort() & 0xffff;
         int totalNumEntries = it.readShort() & 0xffff;
         it.skip(4); // Ignore centralDirSize.
         long centralDirOffset = ((long) it.readInt()) & 0xffffffffL;

         if (numEntries != totalNumEntries || diskNumber != 0 || diskWithCentralDir != 0) {
             throw new ZipException("spanned archives not supported");
         }

         // Seek to the first CDE and read all entries.
         // We have to do this now (from the constructor) rather than lazily because the
         // public API doesn't allow us to throw IOException except from the constructor
         // or from getInputStream.
         RAFStream rafStream = new RAFStream(raf, centralDirOffset);
         BufferedInputStream bufferedStream = new BufferedInputStream(rafStream, 4096);
         byte[] hdrBuf = new byte[CENHDR]; // Reuse the same buffer for each entry.
         for (int i = 0; i < numEntries; ++i) {
             ZipEntry newEntry = new ZipEntry(hdrBuf, bufferedStream);
             entries.put(newEntry.getName(), newEntry);
         }
     }

     /**
      * Wrap a stream around a RandomAccessFile.  The RandomAccessFile is shared
      * among all streams returned by getInputStream(), so we have to synchronize
      * access to it.  (We can optimize this by adding buffering here to reduce
      * collisions.)
      *
      * <p>We could support mark/reset, but we don't currently need them.
      */
     static class RAFStream extends InputStream {
         private final RandomAccessFile sharedRaf;
         private long length;
         private long offset;

         public RAFStream(RandomAccessFile raf, long initialOffset) throws IOException {
             sharedRaf = raf;
             offset = initialOffset;
             length = raf.length();
         }

         @Override public int available() throws IOException {
             return (offset < length ? 1 : 0);
         }

         @Override public int read() throws IOException {
             return Streams.readSingleByte(this);
         }

         @Override public int read(byte[] b, int off, int len) throws IOException {
             synchronized (sharedRaf) {
                 sharedRaf.seek(offset);
                 if (len > length - offset) {
                     len = (int) (length - offset);
                 }
                 int count = sharedRaf.read(b, off, len);
                 if (count > 0) {
                     offset += count;
                     return count;
                 } else {
                     return -1;
                 }
             }
         }

         @Override public long skip(long byteCount) throws IOException {
             if (byteCount > length - offset) {
                 byteCount = length - offset;
             }
             offset += byteCount;
             return byteCount;
         }

         public int fill(Inflater inflater, int nativeEndBufSize) throws IOException {
             synchronized (sharedRaf) {
                 int len = Math.min((int) (length - offset), nativeEndBufSize);
                 int cnt = inflater.setFileInput(sharedRaf.getFD(), offset, nativeEndBufSize);
                 // setFileInput read from the file, so we need to get the OS and RAFStream back
                 // in sync...
                 skip(cnt);
                 return len;
             }
         }
     }

     static class ZipInflaterInputStream extends InflaterInputStream {
         private final ZipEntry entry;
         private long bytesRead = 0;

         public ZipInflaterInputStream(InputStream is, Inflater inf, int bsize, ZipEntry entry) {
             super(is, inf, bsize);
             this.entry = entry;
         }

         @Override public int read(byte[] buffer, int off, int nbytes) throws IOException {
             int i = super.read(buffer, off, nbytes);
             if (i != -1) {
                 bytesRead += i;
             }
             return i;
         }

         @Override public int available() throws IOException {
             if (closed) {
                 // Our superclass will throw an exception, but there's a jtreg test that
                 // explicitly checks that the InputStream returned from ZipFile.getInputStream
                 // returns 0 even when closed.
                 return 0;
             }
             return super.available() == 0 ? 0 : (int) (entry.getSize() - bytesRead);
         }
     }
 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one or more
	* contributor license agreements. See the NOTICE file distributed with
	* this work for additional information regarding copyright ownership.
	* The ASF licenses this file to You under the Apache License, Version 2.0
	* (the "License"); you may not use this file except in compliance with
	* the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	package java.util.zip;

	import dalvik.system.CloseGuard;
	import java.io.BufferedInputStream;
	import java.io.EOFException;
	import java.io.DataInputStream;
	import java.io.File;
	import java.io.IOException;
	import java.io.InputStream;
	import java.io.RandomAccessFile;
	import java.nio.ByteOrder;
	import java.util.Enumeration;
	import java.util.Iterator;
	import java.util.LinkedHashMap;
	import libcore.io.BufferIterator;
	import libcore.io.HeapBufferIterator;
	import libcore.io.Streams;

	/**
	* This class provides random read access to a zip file. You pay more to read
	* the zip file's central directory up front (from the constructor), but if you're using
	* {@link #getEntry} to look up multiple files by name, you get the benefit of this index.
	*
	* <p>If you only want to iterate through all the files (using {@link #entries}, you should
	* consider {@link ZipInputStream}, which provides stream-like read access to a zip file and
	* has a lower up-front cost because you don't pay to build an in-memory index.
	*
	* <p>If you want to create a zip file, use {@link ZipOutputStream}. There is no API for updating
	* an existing zip file.
	*/
	public class ZipFile implements ZipConstants {
	/**
	* General Purpose Bit Flags, Bit 3.
	* If this bit is set, the fields crc-32, compressed
	* size and uncompressed size are set to zero in the
	* local header. The correct values are put in the
	* data descriptor immediately following the compressed
	* data. (Note: PKZIP version 2.04g for DOS only
	* recognizes this bit for method 8 compression, newer
	* versions of PKZIP recognize this bit for any
	* compression method.)
	*/
	static final int GPBF_DATA_DESCRIPTOR_FLAG = 1 << 3;

	/**
	* General Purpose Bit Flags, Bit 11.
	* Language encoding flag (EFS). If this bit is set,
	* the filename and comment fields for this file
	* must be encoded using UTF-8.
	*/
	static final int GPBF_UTF8_FLAG = 1 << 11;

	/**
	* Open zip file for reading.
	*/
	public static final int OPEN_READ = 1;

	/**
	* Delete zip file when closed.
	*/
	public static final int OPEN_DELETE = 4;

	private final String filename;

	private File fileToDeleteOnClose;

	private RandomAccessFile raf;

	private final LinkedHashMap<String, ZipEntry> entries = new LinkedHashMap<String, ZipEntry>();

	private final CloseGuard guard = CloseGuard.get();

	/**
	* Constructs a new {@code ZipFile} allowing read access to the contents of the given file.
	* @throws ZipException if a zip error occurs.
	* @throws IOException if an {@code IOException} occurs.
	*/
	public ZipFile(File file) throws ZipException, IOException {
	this(file, OPEN_READ);
	}

	/**
	* Constructs a new {@code ZipFile} allowing read access to the contents of the given file.
	* @throws IOException if an IOException occurs.
	*/
	public ZipFile(String name) throws IOException {
	this(new File(name), OPEN_READ);
	}

	/**
	* Constructs a new {@code ZipFile} allowing access to the given file.
	* The {@code mode} must be either {@code OPEN_READ} or {@code OPEN_READ\|OPEN_DELETE}.
	*
	* <p>If the {@code OPEN_DELETE} flag is supplied, the file will be deleted at or before the
	* time that the {@code ZipFile} is closed (the contents will remain accessible until
	* this {@code ZipFile} is closed); it also calls {@code File.deleteOnExit}.
	*
	* @throws IOException if an {@code IOException} occurs.
	*/
	public ZipFile(File file, int mode) throws IOException {
	filename = file.getPath();
	if (mode != OPEN_READ && mode != (OPEN_READ \| OPEN_DELETE)) {
	throw new IllegalArgumentException("Bad mode: " + mode);
	}

	if ((mode & OPEN_DELETE) != 0) {
	fileToDeleteOnClose = file;
	fileToDeleteOnClose.deleteOnExit();
	} else {
	fileToDeleteOnClose = null;
	}

	raf = new RandomAccessFile(filename, "r");

	readCentralDir();
	guard.open("close");
	}

	@Override protected void finalize() throws IOException {
	try {
	if (guard != null) {
	guard.warnIfOpen();
	}
	} finally {
	try {
	super.finalize();
	} catch (Throwable t) {
	throw new AssertionError(t);
	}
	}
	}

	/**
	* Closes this zip file. This method is idempotent. This method may cause I/O if the
	* zip file needs to be deleted.
	*
	* @throws IOException
	* if an IOException occurs.
	*/
	public void close() throws IOException {
	guard.close();

	RandomAccessFile localRaf = raf;
	if (localRaf != null) { // Only close initialized instances
	synchronized (localRaf) {
	raf = null;
	localRaf.close();
	}
	if (fileToDeleteOnClose != null) {
	fileToDeleteOnClose.delete();
	fileToDeleteOnClose = null;
	}
	}
	}

	private void checkNotClosed() {
	if (raf == null) {
	throw new IllegalStateException("Zip file closed");
	}
	}

	/**
	* Returns an enumeration of the entries. The entries are listed in the
	* order in which they appear in the zip file.
	*
	* <p>If you only need to iterate over the entries in a zip file, and don't
	* need random-access entry lookup by name, you should probably use {@link ZipInputStream}
	* instead, to avoid paying to construct the in-memory index.
	*
	* @throws IllegalStateException if this zip file has been closed.
	*/
	public Enumeration<? extends ZipEntry> entries() {
	checkNotClosed();
	final Iterator<ZipEntry> iterator = entries.values().iterator();

	return new Enumeration<ZipEntry>() {
	public boolean hasMoreElements() {
	checkNotClosed();
	return iterator.hasNext();
	}

	public ZipEntry nextElement() {
	checkNotClosed();
	return iterator.next();
	}
	};
	}

	/**
	* Returns the zip entry with the given name, or null if there is no such entry.
	*
	* @throws IllegalStateException if this zip file has been closed.
	*/
	public ZipEntry getEntry(String entryName) {
	checkNotClosed();
	if (entryName == null) {
	throw new NullPointerException("entryName == null");
	}

	ZipEntry ze = entries.get(entryName);
	if (ze == null) {
	ze = entries.get(entryName + "/");
	}
	return ze;
	}

	/**
	* Returns an input stream on the data of the specified {@code ZipEntry}.
	*
	* @param entry
	* the ZipEntry.
	* @return an input stream of the data contained in the {@code ZipEntry}.
	* @throws IOException
	* if an {@code IOException} occurs.
	* @throws IllegalStateException if this zip file has been closed.
	*/
	public InputStream getInputStream(ZipEntry entry) throws IOException {
	// Make sure this ZipEntry is in this Zip file. We run it through the name lookup.
	entry = getEntry(entry.getName());
	if (entry == null) {
	return null;
	}

	// Create an InputStream at the right part of the file.
	RandomAccessFile localRaf = raf;
	synchronized (localRaf) {
	// We don't know the entry data's start position. All we have is the
	// position of the entry's local header. At position 28 we find the
	// length of the extra data. In some cases this length differs from
	// the one coming in the central header.
	RAFStream rafStream = new RAFStream(localRaf, entry.localHeaderRelOffset + 28);
	DataInputStream is = new DataInputStream(rafStream);
	int localExtraLenOrWhatever = Short.reverseBytes(is.readShort());
	is.close();

	// Skip the name and this "extra" data or whatever it is:
	rafStream.skip(entry.nameLength + localExtraLenOrWhatever);
	rafStream.length = rafStream.offset + entry.compressedSize;
	if (entry.compressionMethod == ZipEntry.DEFLATED) {
	int bufSize = Math.max(1024, (int)Math.min(entry.getSize(), 65535L));
	return new ZipInflaterInputStream(rafStream, new Inflater(true), bufSize, entry);
	} else {
	return rafStream;
	}
	}
	}

	/**
	* Gets the file name of this {@code ZipFile}.
	*
	* @return the file name of this {@code ZipFile}.
	*/
	public String getName() {
	return filename;
	}

	/**
	* Returns the number of {@code ZipEntries} in this {@code ZipFile}.
	*
	* @return the number of entries in this file.
	* @throws IllegalStateException if this zip file has been closed.
	*/
	public int size() {
	checkNotClosed();
	return entries.size();
	}

	/**
	* Find the central directory and read the contents.
	*
	* <p>The central directory can be followed by a variable-length comment
	* field, so we have to scan through it backwards. The comment is at
	* most 64K, plus we have 18 bytes for the end-of-central-dir stuff
	* itself, plus apparently sometimes people throw random junk on the end
	* just for the fun of it.
	*
	* <p>This is all a little wobbly. If the wrong value ends up in the EOCD
	* area, we're hosed. This appears to be the way that everybody handles
	* it though, so we're in good company if this fails.
	*/
	private void readCentralDir() throws IOException {
	// Scan back, looking for the End Of Central Directory field. If the zip file doesn't
	// have an overall comment (unrelated to any per-entry comments), we'll hit the EOCD
	// on the first try.
	// No need to synchronize raf here -- we only do this when we first open the zip file.
	long scanOffset = raf.length() - ENDHDR;
	if (scanOffset < 0) {
	throw new ZipException("File too short to be a zip file: " + raf.length());
	}

	long stopOffset = scanOffset - 65536;
	if (stopOffset < 0) {
	stopOffset = 0;
	}

	final int ENDHEADERMAGIC = 0x06054b50;
	while (true) {
	raf.seek(scanOffset);
	if (Integer.reverseBytes(raf.readInt()) == ENDHEADERMAGIC) {
	break;
	}

	scanOffset--;
	if (scanOffset < stopOffset) {
	throw new ZipException("EOCD not found; not a zip file?");
	}
	}

	// Read the End Of Central Directory. We could use ENDHDR instead of the magic number 18,
	// but we don't actually need all the header.
	byte[] eocd = new byte[18];
	raf.readFully(eocd);

	// Pull out the information we need.
	BufferIterator it = HeapBufferIterator.iterator(eocd, 0, eocd.length, ByteOrder.LITTLE_ENDIAN);
	int diskNumber = it.readShort() & 0xffff;
	int diskWithCentralDir = it.readShort() & 0xffff;
	int numEntries = it.readShort() & 0xffff;
	int totalNumEntries = it.readShort() & 0xffff;
	it.skip(4); // Ignore centralDirSize.
	long centralDirOffset = ((long) it.readInt()) & 0xffffffffL;

	if (numEntries != totalNumEntries \|\| diskNumber != 0 \|\| diskWithCentralDir != 0) {
	throw new ZipException("spanned archives not supported");
	}

	// Seek to the first CDE and read all entries.
	// We have to do this now (from the constructor) rather than lazily because the
	// public API doesn't allow us to throw IOException except from the constructor
	// or from getInputStream.
	RAFStream rafStream = new RAFStream(raf, centralDirOffset);
	BufferedInputStream bufferedStream = new BufferedInputStream(rafStream, 4096);
	byte[] hdrBuf = new byte[CENHDR]; // Reuse the same buffer for each entry.
	for (int i = 0; i < numEntries; ++i) {
	ZipEntry newEntry = new ZipEntry(hdrBuf, bufferedStream);
	entries.put(newEntry.getName(), newEntry);
	}
	}

	/**
	* Wrap a stream around a RandomAccessFile. The RandomAccessFile is shared
	* among all streams returned by getInputStream(), so we have to synchronize
	* access to it. (We can optimize this by adding buffering here to reduce
	* collisions.)
	*
	* <p>We could support mark/reset, but we don't currently need them.
	*/
	static class RAFStream extends InputStream {
	private final RandomAccessFile sharedRaf;
	private long length;
	private long offset;

	public RAFStream(RandomAccessFile raf, long initialOffset) throws IOException {
	sharedRaf = raf;
	offset = initialOffset;
	length = raf.length();
	}

	@Override public int available() throws IOException {
	return (offset < length ? 1 : 0);
	}

	@Override public int read() throws IOException {
	return Streams.readSingleByte(this);
	}

	@Override public int read(byte[] b, int off, int len) throws IOException {
	synchronized (sharedRaf) {
	sharedRaf.seek(offset);
	if (len > length - offset) {
	len = (int) (length - offset);
	}
	int count = sharedRaf.read(b, off, len);
	if (count > 0) {
	offset += count;
	return count;
	} else {
	return -1;
	}
	}
	}

	@Override public long skip(long byteCount) throws IOException {
	if (byteCount > length - offset) {
	byteCount = length - offset;
	}
	offset += byteCount;
	return byteCount;
	}

	public int fill(Inflater inflater, int nativeEndBufSize) throws IOException {
	synchronized (sharedRaf) {
	int len = Math.min((int) (length - offset), nativeEndBufSize);
	int cnt = inflater.setFileInput(sharedRaf.getFD(), offset, nativeEndBufSize);
	// setFileInput read from the file, so we need to get the OS and RAFStream back
	// in sync...
	skip(cnt);
	return len;
	}
	}
	}

	static class ZipInflaterInputStream extends InflaterInputStream {
	private final ZipEntry entry;
	private long bytesRead = 0;

	public ZipInflaterInputStream(InputStream is, Inflater inf, int bsize, ZipEntry entry) {
	super(is, inf, bsize);
	this.entry = entry;
	}

	@Override public int read(byte[] buffer, int off, int nbytes) throws IOException {
	int i = super.read(buffer, off, nbytes);
	if (i != -1) {
	bytesRead += i;
	}
	return i;
	}

	@Override public int available() throws IOException {
	if (closed) {
	// Our superclass will throw an exception, but there's a jtreg test that
	// explicitly checks that the InputStream returned from ZipFile.getInputStream
	// returns 0 even when closed.
	return 0;
	}
	return super.available() == 0 ? 0 : (int) (entry.getSize() - bytesRead);
	}
	}
	}