mirror of git://gcc.gnu.org/git/gcc.git
249 lines
6.4 KiB
Java
249 lines
6.4 KiB
Java
/* InflaterInputStream.java - Input stream filter for decompressing
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Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004
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Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package java.util.zip;
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import java.io.FilterInputStream;
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import java.io.IOException;
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import java.io.InputStream;
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/**
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* This filter stream is used to decompress data compressed in the "deflate"
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* format. The "deflate" format is described in RFC 1951.
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*
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* This stream may form the basis for other decompression filters, such
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* as the <code>GZIPInputStream</code>.
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*
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* @author John Leuner
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* @author Tom Tromey
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* @since 1.1
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*/
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public class InflaterInputStream extends FilterInputStream
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{
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/**
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* Decompressor for this filter
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*/
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protected Inflater inf;
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/**
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* Byte array used as a buffer
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*/
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protected byte[] buf;
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/**
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* Size of buffer
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*/
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protected int len;
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// We just use this if we are decoding one byte at a time with the
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// read() call.
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private byte[] onebytebuffer = new byte[1];
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/**
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* Create an InflaterInputStream with the default decompresseor
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* and a default buffer size.
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*
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* @param in the InputStream to read bytes from
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*/
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public InflaterInputStream(InputStream in)
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{
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this(in, new Inflater(), 4096);
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}
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/**
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* Create an InflaterInputStream with the specified decompresseor
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* and a default buffer size.
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*
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* @param in the InputStream to read bytes from
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* @param inf the decompressor used to decompress data read from in
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*/
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public InflaterInputStream(InputStream in, Inflater inf)
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{
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this(in, inf, 4096);
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}
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/**
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* Create an InflaterInputStream with the specified decompresseor
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* and a specified buffer size.
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*
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* @param in the InputStream to read bytes from
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* @param inf the decompressor used to decompress data read from in
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* @param size size of the buffer to use
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*/
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public InflaterInputStream(InputStream in, Inflater inf, int size)
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{
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super(in);
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if (in == null)
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throw new NullPointerException("in may not be null");
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if (inf == null)
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throw new NullPointerException("inf may not be null");
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if (size < 0)
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throw new IllegalArgumentException("size may not be negative");
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this.inf = inf;
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this.buf = new byte [size];
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}
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/**
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* Returns 0 once the end of the stream (EOF) has been reached.
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* Otherwise returns 1.
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*/
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public int available() throws IOException
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{
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// According to the JDK 1.2 docs, this should only ever return 0
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// or 1 and should not be relied upon by Java programs.
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if (inf == null)
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throw new IOException("stream closed");
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return inf.finished() ? 0 : 1;
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}
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/**
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* Closes the input stream
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*/
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public synchronized void close() throws IOException
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{
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inf = null;
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super.close();
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}
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/**
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* Fills the buffer with more data to decompress.
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*/
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protected void fill() throws IOException
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{
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if (in == null)
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throw new ZipException ("InflaterInputStream is closed");
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len = in.read(buf, 0, buf.length);
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if (len >= 0)
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inf.setInput(buf, 0, len);
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}
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/**
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* Reads one byte of decompressed data.
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*
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* The byte is in the lower 8 bits of the int.
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*/
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public int read() throws IOException
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{
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int nread = read(onebytebuffer, 0, 1);
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if (nread > 0)
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return onebytebuffer[0] & 0xff;
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return -1;
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}
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/**
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* Decompresses data into the byte array
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*
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* @param b the array to read and decompress data into
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* @param off the offset indicating where the data should be placed
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* @param len the number of bytes to decompress
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*/
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public int read(byte[] b, int off, int len) throws IOException
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{
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if (inf == null)
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throw new IOException("stream closed");
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if (len == 0)
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return 0;
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if (inf.finished())
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return -1;
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int count = 0;
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while (count == 0)
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{
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if (inf.needsInput())
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fill();
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try
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{
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count = inf.inflate(b, off, len);
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if (count == 0)
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{
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if (this.len == -1)
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{
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// Couldn't get any more data to feed to the Inflater
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return -1;
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}
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if (inf.needsDictionary())
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throw new ZipException("Inflater needs Dictionary");
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}
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}
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catch (DataFormatException dfe)
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{
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throw new ZipException(dfe.getMessage());
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}
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}
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return count;
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}
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/**
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* Skip specified number of bytes of uncompressed data
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*
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* @param n number of bytes to skip
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*/
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public long skip(long n) throws IOException
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{
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if (inf == null)
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throw new IOException("stream closed");
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if (n < 0)
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throw new IllegalArgumentException();
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if (n == 0)
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return 0;
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int buflen = (int) Math.min(n, 2048);
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byte[] tmpbuf = new byte[buflen];
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long skipped = 0L;
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while (n > 0L)
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{
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int numread = read(tmpbuf, 0, buflen);
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if (numread <= 0)
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break;
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n -= numread;
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skipped += numread;
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buflen = (int) Math.min(n, 2048);
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}
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return skipped;
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}
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}
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