1 /* InflaterInputStream.java - Input stream filter for decompressing
2 Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
3 Free Software Foundation, Inc.
5 This file is part of GNU Classpath.
7 GNU Classpath is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GNU Classpath is distributed in the hope that it will be useful, but
13 WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GNU Classpath; see the file COPYING. If not, write to the
19 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
22 Linking this library statically or dynamically with other modules is
23 making a combined work based on this library. Thus, the terms and
24 conditions of the GNU General Public License cover the whole
27 As a special exception, the copyright holders of this library give you
28 permission to link this library with independent modules to produce an
29 executable, regardless of the license terms of these independent
30 modules, and to copy and distribute the resulting executable under
31 terms of your choice, provided that you also meet, for each linked
32 independent module, the terms and conditions of the license of that
33 module. An independent module is a module which is not derived from
34 or based on this library. If you modify this library, you may extend
35 this exception to your version of the library, but you are not
36 obligated to do so. If you do not wish to do so, delete this
37 exception statement from your version. */
40 package java.util.zip;
42 import java.io.FilterInputStream;
43 import java.io.IOException;
44 import java.io.InputStream;
47 * This filter stream is used to decompress data compressed in the "deflate"
48 * format. The "deflate" format is described in RFC 1951.
50 * This stream may form the basis for other decompression filters, such
51 * as the <code>GZIPInputStream</code>.
57 public class InflaterInputStream extends FilterInputStream
60 * Decompressor for this filter
62 protected Inflater inf;
65 * Byte array used as a buffer
74 // We just use this if we are decoding one byte at a time with the
76 private byte[] onebytebuffer = new byte[1];
79 * Create an InflaterInputStream with the default decompresseor
80 * and a default buffer size.
82 * @param in the InputStream to read bytes from
84 public InflaterInputStream(InputStream in)
86 this(in, new Inflater(), 4096);
90 * Create an InflaterInputStream with the specified decompresseor
91 * and a default buffer size.
93 * @param in the InputStream to read bytes from
94 * @param inf the decompressor used to decompress data read from in
96 public InflaterInputStream(InputStream in, Inflater inf)
102 * Create an InflaterInputStream with the specified decompresseor
103 * and a specified buffer size.
105 * @param in the InputStream to read bytes from
106 * @param inf the decompressor used to decompress data read from in
107 * @param size size of the buffer to use
109 public InflaterInputStream(InputStream in, Inflater inf, int size)
114 throw new NullPointerException("in may not be null");
116 throw new NullPointerException("inf may not be null");
118 throw new IllegalArgumentException("size may not be negative");
121 this.buf = new byte [size];
125 * Returns 0 once the end of the stream (EOF) has been reached.
126 * Otherwise returns 1.
128 public int available() throws IOException
130 // According to the JDK 1.2 docs, this should only ever return 0
131 // or 1 and should not be relied upon by Java programs.
133 throw new IOException("stream closed");
134 return inf.finished() ? 0 : 1;
138 * Closes the input stream
140 public synchronized void close() throws IOException
147 * Fills the buffer with more data to decompress.
149 protected void fill() throws IOException
152 throw new ZipException ("InflaterInputStream is closed");
154 len = in.read(buf, 0, buf.length);
157 throw new ZipException("Deflated stream ends early.");
159 inf.setInput(buf, 0, len);
163 * Reads one byte of decompressed data.
165 * The byte is in the lower 8 bits of the int.
167 public int read() throws IOException
169 int nread = read(onebytebuffer, 0, 1);
171 return onebytebuffer[0] & 0xff;
176 * Decompresses data into the byte array
178 * @param b the array to read and decompress data into
179 * @param off the offset indicating where the data should be placed
180 * @param len the number of bytes to decompress
182 public int read(byte[] b, int off, int len) throws IOException
185 throw new IOException("stream closed");
194 if (inf.needsInput())
199 count = inf.inflate(b, off, len);
204 // Couldn't get any more data to feed to the Inflater
207 if (inf.needsDictionary())
208 throw new ZipException("Inflater needs Dictionary");
211 catch (DataFormatException dfe)
213 throw new ZipException(dfe.getMessage());
220 * Skip specified number of bytes of uncompressed data
222 * @param n number of bytes to skip
224 public long skip(long n) throws IOException
227 throw new IOException("stream closed");
229 throw new IllegalArgumentException();
234 int buflen = (int) Math.min(n, 2048);
235 byte[] tmpbuf = new byte[buflen];
240 int numread = read(tmpbuf, 0, buflen);
245 buflen = (int) Math.min(n, 2048);
251 public boolean markSupported()
256 public void mark(int readLimit)
260 public void reset() throws IOException
262 throw new IOException("reset not supported");