Initial revision

From-SVN: r102074

libjava/classpath/java/util/zip/InflaterInputStream.java

@@ -0,0 +1,261 @@
+/* InflaterInputStream.java - Input stream filter for decompressing
+   Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004
+   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., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 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
+  {
+    if (in != null)
+      in.close();
+    in = null;
+  }
+
+  /**
+   * 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)
+      throw new ZipException("Deflated stream ends early.");
+    
+    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;
+
+    int count = 0;
+    for (;;)
+      {
+	
+	try
+	  {
+	    count = inf.inflate(b, off, len);
+	  } 
+	catch (DataFormatException dfe) 
+	  {
+	    throw new ZipException(dfe.getMessage());
+	  }
+
+	if (count > 0)
+	  return count;
+	
+	if (inf.needsDictionary()
+	    | inf.finished())
+	  return -1;
+	else if (inf.needsInput())
+	  fill();
+	else
+	  throw new InternalError("Don't know what to do");
+      }
+  }
+
+  /**
+   * 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");
+  }
+}