| /* InflaterInputStream.java - Input stream filter for decompressing |
| Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005 |
| 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.FilterInputStream; |
| import java.io.IOException; |
| import java.io.InputStream; |
| |
| /** |
| * This filter stream is used to decompress data compressed in the "deflate" |
| * format. The "deflate" format is described in RFC 1951. |
| * |
| * This stream may form the basis for other decompression filters, such |
| * as the <code>GZIPInputStream</code>. |
| * |
| * @author John Leuner |
| * @author Tom Tromey |
| * @since 1.1 |
| */ |
| public class InflaterInputStream extends FilterInputStream |
| { |
| /** |
| * Decompressor for this filter |
| */ |
| protected Inflater inf; |
| |
| /** |
| * Byte array used as a buffer |
| */ |
| protected byte[] buf; |
| |
| /** |
| * Size of buffer |
| */ |
| protected int len; |
| |
| // We just use this if we are decoding one byte at a time with the |
| // read() call. |
| private byte[] onebytebuffer = new byte[1]; |
| |
| /** |
| * Create an InflaterInputStream with the default decompresseor |
| * and a default buffer size. |
| * |
| * @param in the InputStream to read bytes from |
| */ |
| public InflaterInputStream(InputStream in) |
| { |
| this(in, new Inflater(), 4096); |
| } |
| |
| /** |
| * Create an InflaterInputStream with the specified decompresseor |
| * and a default buffer size. |
| * |
| * @param in the InputStream to read bytes from |
| * @param inf the decompressor used to decompress data read from in |
| */ |
| public InflaterInputStream(InputStream in, Inflater inf) |
| { |
| this(in, inf, 4096); |
| } |
| |
| /** |
| * Create an InflaterInputStream with the specified decompresseor |
| * and a specified buffer size. |
| * |
| * @param in the InputStream to read bytes from |
| * @param inf the decompressor used to decompress data read from in |
| * @param size size of the buffer to use |
| */ |
| public InflaterInputStream(InputStream in, Inflater inf, int size) |
| { |
| super(in); |
| |
| if (in == null) |
| throw new NullPointerException("in may not be null"); |
| if (inf == null) |
| throw new NullPointerException("inf may not be null"); |
| if (size < 0) |
| throw new IllegalArgumentException("size may not be negative"); |
| |
| this.inf = inf; |
| this.buf = new byte [size]; |
| } |
| |
| /** |
| * Returns 0 once the end of the stream (EOF) has been reached. |
| * Otherwise returns 1. |
| */ |
| public int available() throws IOException |
| { |
| // According to the JDK 1.2 docs, this should only ever return 0 |
| // or 1 and should not be relied upon by Java programs. |
| if (inf == null) |
| throw new IOException("stream closed"); |
| return inf.finished() ? 0 : 1; |
| } |
| |
| /** |
| * Closes the input stream |
| */ |
| public synchronized void close() throws IOException |
| { |
| inf = null; |
| super.close(); |
| } |
| |
| /** |
| * Fills the buffer with more data to decompress. |
| */ |
| protected void fill() throws IOException |
| { |
| if (in == null) |
| throw new ZipException ("InflaterInputStream is closed"); |
| |
| len = in.read(buf, 0, buf.length); |
| |
| if (len >= 0) |
| inf.setInput(buf, 0, len); |
| } |
| |
| /** |
| * Reads one byte of decompressed data. |
| * |
| * The byte is in the lower 8 bits of the int. |
| */ |
| public int read() throws IOException |
| { |
| int nread = read(onebytebuffer, 0, 1); |
| if (nread > 0) |
| return onebytebuffer[0] & 0xff; |
| return -1; |
| } |
| |
| /** |
| * Decompresses data into the byte array |
| * |
| * @param b the array to read and decompress data into |
| * @param off the offset indicating where the data should be placed |
| * @param len the number of bytes to decompress |
| */ |
| public int read(byte[] b, int off, int len) throws IOException |
| { |
| if (inf == null) |
| throw new IOException("stream closed"); |
| if (len == 0) |
| return 0; |
| if (inf.finished()) |
| return -1; |
| |
| int count = 0; |
| while (count == 0) |
| { |
| if (inf.needsInput()) |
| fill(); |
| |
| try |
| { |
| count = inf.inflate(b, off, len); |
| if (count == 0) |
| { |
| if (this.len == -1) |
| { |
| // Couldn't get any more data to feed to the Inflater |
| return -1; |
| } |
| if (inf.needsDictionary()) |
| throw new ZipException("Inflater needs Dictionary"); |
| } |
| } |
| catch (DataFormatException dfe) |
| { |
| throw new ZipException(dfe.getMessage()); |
| } |
| } |
| return count; |
| } |
| |
| /** |
| * Skip specified number of bytes of uncompressed data |
| * |
| * @param n number of bytes to skip |
| */ |
| public long skip(long n) throws IOException |
| { |
| if (inf == null) |
| throw new IOException("stream closed"); |
| if (n < 0) |
| throw new IllegalArgumentException(); |
| |
| if (n == 0) |
| return 0; |
| |
| int buflen = (int) Math.min(n, 2048); |
| byte[] tmpbuf = new byte[buflen]; |
| |
| long skipped = 0L; |
| while (n > 0L) |
| { |
| int numread = read(tmpbuf, 0, buflen); |
| if (numread <= 0) |
| break; |
| n -= numread; |
| skipped += numread; |
| buflen = (int) Math.min(n, 2048); |
| } |
| |
| return skipped; |
| } |
| |
| public boolean markSupported() |
| { |
| return false; |
| } |
| |
| public void mark(int readLimit) |
| { |
| } |
| |
| public void reset() throws IOException |
| { |
| throw new IOException("reset not supported"); |
| } |
| } |