jaroslav@609: /*
jaroslav@609:  * Copyright (c) 1996, 2006, Oracle and/or its affiliates. All rights reserved.
jaroslav@609:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
jaroslav@609:  *
jaroslav@609:  * This code is free software; you can redistribute it and/or modify it
jaroslav@609:  * under the terms of the GNU General Public License version 2 only, as
jaroslav@609:  * published by the Free Software Foundation.  Oracle designates this
jaroslav@609:  * particular file as subject to the "Classpath" exception as provided
jaroslav@609:  * by Oracle in the LICENSE file that accompanied this code.
jaroslav@609:  *
jaroslav@609:  * This code is distributed in the hope that it will be useful, but WITHOUT
jaroslav@609:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
jaroslav@609:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
jaroslav@609:  * version 2 for more details (a copy is included in the LICENSE file that
jaroslav@609:  * accompanied this code).
jaroslav@609:  *
jaroslav@609:  * You should have received a copy of the GNU General Public License version
jaroslav@609:  * 2 along with this work; if not, write to the Free Software Foundation,
jaroslav@609:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
jaroslav@609:  *
jaroslav@609:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
jaroslav@609:  * or visit www.oracle.com if you need additional information or have any
jaroslav@609:  * questions.
jaroslav@609:  */
jaroslav@609: 
jaroslav@609: package java.util.zip;
jaroslav@609: 
jaroslav@609: import java.io.FilterInputStream;
jaroslav@609: import java.io.InputStream;
jaroslav@609: import java.io.IOException;
jaroslav@609: import java.io.EOFException;
jaroslav@609: 
jaroslav@609: /**
jaroslav@609:  * This class implements a stream filter for uncompressing data in the
jaroslav@609:  * "deflate" compression format. It is also used as the basis for other
jaroslav@609:  * decompression filters, such as GZIPInputStream.
jaroslav@609:  *
jaroslav@609:  * @see         Inflater
jaroslav@609:  * @author      David Connelly
jaroslav@609:  */
jaroslav@609: public
jaroslav@609: class InflaterInputStream extends FilterInputStream {
jaroslav@609:     /**
jaroslav@609:      * Decompressor for this stream.
jaroslav@609:      */
jaroslav@609:     protected Inflater inf;
jaroslav@609: 
jaroslav@609:     /**
jaroslav@609:      * Input buffer for decompression.
jaroslav@609:      */
jaroslav@609:     protected byte[] buf;
jaroslav@609: 
jaroslav@609:     /**
jaroslav@609:      * Length of input buffer.
jaroslav@609:      */
jaroslav@609:     protected int len;
jaroslav@609: 
jaroslav@609:     private boolean closed = false;
jaroslav@609:     // this flag is set to true after EOF has reached
jaroslav@609:     private boolean reachEOF = false;
jaroslav@609: 
jaroslav@609:     /**
jaroslav@609:      * Check to make sure that this stream has not been closed
jaroslav@609:      */
jaroslav@609:     private void ensureOpen() throws IOException {
jaroslav@609:         if (closed) {
jaroslav@609:             throw new IOException("Stream closed");
jaroslav@609:         }
jaroslav@609:     }
jaroslav@609: 
jaroslav@609: 
jaroslav@609:     /**
jaroslav@609:      * Creates a new input stream with the specified decompressor and
jaroslav@609:      * buffer size.
jaroslav@609:      * @param in the input stream
jaroslav@609:      * @param inf the decompressor ("inflater")
jaroslav@609:      * @param size the input buffer size
jaroslav@609:      * @exception IllegalArgumentException if size is <= 0
jaroslav@609:      */
jaroslav@609:     public InflaterInputStream(InputStream in, Inflater inf, int size) {
jaroslav@609:         super(in);
jaroslav@609:         if (in == null || inf == null) {
jaroslav@609:             throw new NullPointerException();
jaroslav@609:         } else if (size <= 0) {
jaroslav@609:             throw new IllegalArgumentException("buffer size <= 0");
jaroslav@609:         }
jaroslav@609:         this.inf = inf;
jaroslav@609:         buf = new byte[size];
jaroslav@609:     }
jaroslav@609: 
jaroslav@609:     /**
jaroslav@609:      * Creates a new input stream with the specified decompressor and a
jaroslav@609:      * default buffer size.
jaroslav@609:      * @param in the input stream
jaroslav@609:      * @param inf the decompressor ("inflater")
jaroslav@609:      */
jaroslav@609:     public InflaterInputStream(InputStream in, Inflater inf) {
jaroslav@609:         this(in, inf, 512);
jaroslav@609:     }
jaroslav@609: 
jaroslav@609:     boolean usesDefaultInflater = false;
jaroslav@609: 
jaroslav@609:     /**
jaroslav@609:      * Creates a new input stream with a default decompressor and buffer size.
jaroslav@609:      * @param in the input stream
jaroslav@609:      */
jaroslav@609:     public InflaterInputStream(InputStream in) {
jaroslav@609:         this(in, new Inflater());
jaroslav@609:         usesDefaultInflater = true;
jaroslav@609:     }
jaroslav@609: 
jaroslav@609:     private byte[] singleByteBuf = new byte[1];
jaroslav@609: 
jaroslav@609:     /**
jaroslav@609:      * Reads a byte of uncompressed data. This method will block until
jaroslav@609:      * enough input is available for decompression.
jaroslav@609:      * @return the byte read, or -1 if end of compressed input is reached
jaroslav@609:      * @exception IOException if an I/O error has occurred
jaroslav@609:      */
jaroslav@609:     public int read() throws IOException {
jaroslav@609:         ensureOpen();
jaroslav@609:         return read(singleByteBuf, 0, 1) == -1 ? -1 : singleByteBuf[0] & 0xff;
jaroslav@609:     }
jaroslav@609: 
jaroslav@609:     /**
jaroslav@609:      * Reads uncompressed data into an array of bytes. If <code>len</code> is not
jaroslav@609:      * zero, the method will block until some input can be decompressed; otherwise,
jaroslav@609:      * no bytes are read and <code>0</code> is returned.
jaroslav@609:      * @param b the buffer into which the data is read
jaroslav@609:      * @param off the start offset in the destination array <code>b</code>
jaroslav@609:      * @param len the maximum number of bytes read
jaroslav@609:      * @return the actual number of bytes read, or -1 if the end of the
jaroslav@609:      *         compressed input is reached or a preset dictionary is needed
jaroslav@609:      * @exception  NullPointerException If <code>b</code> is <code>null</code>.
jaroslav@609:      * @exception  IndexOutOfBoundsException If <code>off</code> is negative,
jaroslav@609:      * <code>len</code> is negative, or <code>len</code> is greater than
jaroslav@609:      * <code>b.length - off</code>
jaroslav@609:      * @exception ZipException if a ZIP format error has occurred
jaroslav@609:      * @exception IOException if an I/O error has occurred
jaroslav@609:      */
jaroslav@609:     public int read(byte[] b, int off, int len) throws IOException {
jaroslav@609:         ensureOpen();
jaroslav@609:         if (b == null) {
jaroslav@609:             throw new NullPointerException();
jaroslav@609:         } else if (off < 0 || len < 0 || len > b.length - off) {
jaroslav@609:             throw new IndexOutOfBoundsException();
jaroslav@609:         } else if (len == 0) {
jaroslav@609:             return 0;
jaroslav@609:         }
jaroslav@609:         try {
jaroslav@609:             int n;
jaroslav@609:             while ((n = inf.inflate(b, off, len)) == 0) {
jaroslav@609:                 if (inf.finished() || inf.needsDictionary()) {
jaroslav@609:                     reachEOF = true;
jaroslav@609:                     return -1;
jaroslav@609:                 }
jaroslav@609:                 if (inf.needsInput()) {
jaroslav@609:                     fill();
jaroslav@609:                 }
jaroslav@609:             }
jaroslav@609:             return n;
jaroslav@609:         } catch (DataFormatException e) {
jaroslav@609:             String s = e.getMessage();
jaroslav@609:             throw new ZipException(s != null ? s : "Invalid ZLIB data format");
jaroslav@609:         }
jaroslav@609:     }
jaroslav@609: 
jaroslav@609:     /**
jaroslav@609:      * Returns 0 after EOF has been reached, otherwise always return 1.
jaroslav@609:      * <p>
jaroslav@609:      * Programs should not count on this method to return the actual number
jaroslav@609:      * of bytes that could be read without blocking.
jaroslav@609:      *
jaroslav@609:      * @return     1 before EOF and 0 after EOF.
jaroslav@609:      * @exception  IOException  if an I/O error occurs.
jaroslav@609:      *
jaroslav@609:      */
jaroslav@609:     public int available() throws IOException {
jaroslav@609:         ensureOpen();
jaroslav@609:         if (reachEOF) {
jaroslav@609:             return 0;
jaroslav@609:         } else {
jaroslav@609:             return 1;
jaroslav@609:         }
jaroslav@609:     }
jaroslav@609: 
jaroslav@609:     private byte[] b = new byte[512];
jaroslav@609: 
jaroslav@609:     /**
jaroslav@609:      * Skips specified number of bytes of uncompressed data.
jaroslav@609:      * @param n the number of bytes to skip
jaroslav@609:      * @return the actual number of bytes skipped.
jaroslav@609:      * @exception IOException if an I/O error has occurred
jaroslav@609:      * @exception IllegalArgumentException if n < 0
jaroslav@609:      */
jaroslav@609:     public long skip(long n) throws IOException {
jaroslav@609:         if (n < 0) {
jaroslav@609:             throw new IllegalArgumentException("negative skip length");
jaroslav@609:         }
jaroslav@609:         ensureOpen();
jaroslav@609:         int max = (int)Math.min(n, Integer.MAX_VALUE);
jaroslav@609:         int total = 0;
jaroslav@609:         while (total < max) {
jaroslav@609:             int len = max - total;
jaroslav@609:             if (len > b.length) {
jaroslav@609:                 len = b.length;
jaroslav@609:             }
jaroslav@609:             len = read(b, 0, len);
jaroslav@609:             if (len == -1) {
jaroslav@609:                 reachEOF = true;
jaroslav@609:                 break;
jaroslav@609:             }
jaroslav@609:             total += len;
jaroslav@609:         }
jaroslav@609:         return total;
jaroslav@609:     }
jaroslav@609: 
jaroslav@609:     /**
jaroslav@609:      * Closes this input stream and releases any system resources associated
jaroslav@609:      * with the stream.
jaroslav@609:      * @exception IOException if an I/O error has occurred
jaroslav@609:      */
jaroslav@609:     public void close() throws IOException {
jaroslav@609:         if (!closed) {
jaroslav@609:             if (usesDefaultInflater)
jaroslav@609:                 inf.end();
jaroslav@609:             in.close();
jaroslav@609:             closed = true;
jaroslav@609:         }
jaroslav@609:     }
jaroslav@609: 
jaroslav@609:     /**
jaroslav@609:      * Fills input buffer with more data to decompress.
jaroslav@609:      * @exception IOException if an I/O error has occurred
jaroslav@609:      */
jaroslav@609:     protected void fill() throws IOException {
jaroslav@609:         ensureOpen();
jaroslav@609:         len = in.read(buf, 0, buf.length);
jaroslav@609:         if (len == -1) {
jaroslav@609:             throw new EOFException("Unexpected end of ZLIB input stream");
jaroslav@609:         }
jaroslav@609:         inf.setInput(buf, 0, len);
jaroslav@609:     }
jaroslav@609: 
jaroslav@609:     /**
jaroslav@609:      * Tests if this input stream supports the <code>mark</code> and
jaroslav@609:      * <code>reset</code> methods. The <code>markSupported</code>
jaroslav@609:      * method of <code>InflaterInputStream</code> returns
jaroslav@609:      * <code>false</code>.
jaroslav@609:      *
jaroslav@609:      * @return  a <code>boolean</code> indicating if this stream type supports
jaroslav@609:      *          the <code>mark</code> and <code>reset</code> methods.
jaroslav@609:      * @see     java.io.InputStream#mark(int)
jaroslav@609:      * @see     java.io.InputStream#reset()
jaroslav@609:      */
jaroslav@609:     public boolean markSupported() {
jaroslav@609:         return false;
jaroslav@609:     }
jaroslav@609: 
jaroslav@609:     /**
jaroslav@609:      * Marks the current position in this input stream.
jaroslav@609:      *
jaroslav@609:      * <p> The <code>mark</code> method of <code>InflaterInputStream</code>
jaroslav@609:      * does nothing.
jaroslav@609:      *
jaroslav@609:      * @param   readlimit   the maximum limit of bytes that can be read before
jaroslav@609:      *                      the mark position becomes invalid.
jaroslav@609:      * @see     java.io.InputStream#reset()
jaroslav@609:      */
jaroslav@609:     public synchronized void mark(int readlimit) {
jaroslav@609:     }
jaroslav@609: 
jaroslav@609:     /**
jaroslav@609:      * Repositions this stream to the position at the time the
jaroslav@609:      * <code>mark</code> method was last called on this input stream.
jaroslav@609:      *
jaroslav@609:      * <p> The method <code>reset</code> for class
jaroslav@609:      * <code>InflaterInputStream</code> does nothing except throw an
jaroslav@609:      * <code>IOException</code>.
jaroslav@609:      *
jaroslav@609:      * @exception  IOException  if this method is invoked.
jaroslav@609:      * @see     java.io.InputStream#mark(int)
jaroslav@609:      * @see     java.io.IOException
jaroslav@609:      */
jaroslav@609:     public synchronized void reset() throws IOException {
jaroslav@609:         throw new IOException("mark/reset not supported");
jaroslav@609:     }
jaroslav@609: }