-// GZIPInputStream.java - Input tiler for reading gzip file.
-
-/* Copyright (C) 1999 Red Hat, Inc.
-
- This file is part of libgcj.
-
-This software is copyrighted work licensed under the terms of the
-Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
-details. */
+/* GZIPInputStream.java - Input filter for reading gzip file
+ Copyright (C) 1999, 2000, 2001, 2002, 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., 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.IOException;
/**
+ * This filter stream is used to decompress a "GZIP" format stream.
+ * The "GZIP" format is described in RFC 1952.
+ *
+ * @author John Leuner
* @author Tom Tromey
- * @date May 17, 1999
+ * @since JDK 1.1
*/
-
-/* Written using on-line Java Platform 1.2 API Specification
- * and JCL book.
- * Believed complete and correct.
- */
-
-public class GZIPInputStream extends InflaterInputStream
+public class GZIPInputStream
+ extends InflaterInputStream
{
+ /**
+ * The magic number found at the start of a GZIP stream.
+ */
public static final int GZIP_MAGIC = 0x8b1f;
- public void close () throws IOException
- {
- // Nothing to do here.
- super.close();
- }
+ static final int Z_DEFLATED = 8;
- public GZIPInputStream (InputStream istream) throws IOException
- {
- this (istream, 512);
- }
+ /**
+ * The mask for bit 1 of the flag byte.
+ */
+ static final int HEAD_CRC = 0x02;
+
+ /**
+ * The mask for bit 2 of the flag byte.
+ */
+ static final int EXTRA_FIELD = 0x04;
+
+ /**
+ * The mask for bit 3 of the flag byte.
+ */
+ static final int ORIG_NAME = 0x08;
+
+ /**
+ * The mask for bit 4 of the flag byte.
+ */
+ static final int COMMENT = 0x10;
+
+ /**
+ * The mask for all reserved bits of the flag byte.
+ */
+ static final int RESERVED = 0xe0;
+
+ /**
+ * The CRC-32 checksum value for uncompressed data.
+ */
+ protected CRC32 crc;
+
+ /**
+ * Indicates whether or not the end of the stream has been reached.
+ */
+ protected boolean eos;
- private final int eof_read () throws IOException
+ /**
+ * Creates a GZIPInputStream with the default buffer size.
+ *
+ * @param in The stream to read compressed data from
+ * (in GZIP format).
+ *
+ * @throws IOException if an error occurs during an I/O operation.
+ */
+ public GZIPInputStream(InputStream in)
+ throws IOException
{
- int r = in.read();
- if (r == -1)
- throw new ZipException ("gzip header corrupted");
- return r & 0xff;
+ this(in, 4096);
}
- public GZIPInputStream (InputStream istream, int readsize)
+ /**
+ * Creates a GZIPInputStream with the specified buffer size.
+ *
+ * @param in The stream to read compressed data from
+ * (in GZIP format).
+ * @param size The size of the buffer to use.
+ *
+ * @throws IOException if an error occurs during an I/O operation.
+ * @throws IllegalArgumentException if <code>size</code>
+ * is less than or equal to 0.
+ */
+ public GZIPInputStream(InputStream in, int size)
throws IOException
{
- super (istream, new Inflater (true), readsize);
+ super(in, new Inflater(true), size);
// NOTE: header reading code taken from zlib's gzio.c.
// Read the magic number.
- int magic = eof_read () | (eof_read () << 8);
+ int magic = eof_read() | (eof_read() << 8);
if (magic != GZIP_MAGIC)
- throw new ZipException ("gzip header corrupted");
+ throw new ZipException("gzip header corrupted");
- int method = eof_read ();
- int flags = eof_read ();
+ int method = eof_read();
+ int flags = eof_read();
// Test from zlib.
if (method != Z_DEFLATED || (flags & RESERVED) != 0)
- throw new ZipException ("gzip header corrupted");
+ throw new ZipException("gzip header corrupted");
// Discard time, xflags, OS code.
for (int i = 0; i < 6; ++i)
- eof_read ();
+ eof_read();
// Skip the extra field.
if ((flags & EXTRA_FIELD) != 0)
{
- int len = eof_read () | (eof_read () << 8);
+ int len = eof_read() | (eof_read() << 8);
while (len-- != 0)
- eof_read ();
+ eof_read();
}
if ((flags & ORIG_NAME) != 0)
{
while (true)
{
- int c = eof_read ();
+ int c = eof_read();
if (c == 0)
break;
}
{
while (true)
{
- int c = eof_read ();
+ int c = eof_read();
if (c == 0)
break;
}
if ((flags & HEAD_CRC) != 0)
{
// FIXME: consider checking CRC of the header.
- eof_read ();
- eof_read ();
+ eof_read();
+ eof_read();
}
- crc = new CRC32 ();
+ crc = new CRC32();
+ }
+
+ /**
+ * Closes the input stream.
+ *
+ * @throws IOException if an error occurs during an I/O operation.
+ */
+ public void close()
+ throws IOException
+ {
+ // Nothing to do here.
+ super.close();
+ }
+
+ private final int eof_read() throws IOException
+ {
+ int r = in.read();
+ if (r == -1)
+ throw new ZipException("gzip header corrupted");
+ return r & 0xff;
}
- public int read (byte[] buf, int off, int len) throws IOException
+ /**
+ * Reads in GZIP-compressed data and stores it in uncompressed form
+ * into an array of bytes. The method will block until either
+ * enough input data becomes available or the compressed stream
+ * reaches its end.
+ *
+ * @param buf the buffer into which the uncompressed data will
+ * be stored.
+ * @param offset the offset indicating where in <code>buf</code>
+ * the uncompressed data should be placed.
+ * @param len the number of uncompressed bytes to be read.
+ */
+ public int read(byte[] buf, int offset, int len) throws IOException
{
if (eos)
return -1;
- int r = super.read(buf, off, len);
+ int r = super.read(buf, offset, len);
if (r == -1)
{
eos = true;
- int header_crc = read4 ();
+
+ byte[] tmp = new byte[8];
+ // First copy remaining bytes from inflater input buffer.
+ int avail = inf.getRemaining();
+ System.arraycopy(this.buf, this.len - avail, tmp, 0, avail);
+
+ // Now read remaining bytes from wrapped input stream.
+ for (int i = avail; i < 8; ++i)
+ {
+ tmp[i] = (byte) eof_read();
+ }
+
+ // Be careful to avoid sign extension here; CRC32.getValue()
+ // returns a long.
+ long header_crc = read4(tmp, 0) & 0xffffffffL;
if (crc.getValue() != header_crc)
- throw new ZipException ("corrupted gzip file");
- // Read final `ISIZE' field.
- // FIXME: should we check this length?
- read4 ();
+ throw new ZipException("corrupted gzip file - crc mismatch");
+ int isize = read4(tmp, 4);
+ if (inf.getTotalOut() != isize)
+ throw new ZipException("corrupted gzip file - size mismatch");
return -1;
}
- crc.update(buf, off, r);
+ crc.update(buf, offset, r);
return r;
}
- private final int read4 () throws IOException
+ private final int read4(byte[] buf, int offset) throws IOException
{
- int byte0 = in.read();
- int byte1 = in.read();
- int byte2 = in.read();
- int byte3 = in.read();
- if (byte3 < 0)
- throw new ZipException (".zip archive ended prematurely");
- return ((byte3 & 0xFF) << 24) + ((byte2 & 0xFF) << 16)
- + ((byte1 & 0xFF) << 8) + (byte0 & 0xFF);
+ return (((buf[offset + 3] & 0xFF) << 24) + ((buf[offset + 2] & 0xFF) << 16)
+ + ((buf[offset + 1] & 0xFF) << 8) + (buf[offset] & 0xFF));
}
-
- // Checksum used by this input stream.
- protected CRC32 crc;
-
- // Indicates whether end-of-stream has been reached.
- protected boolean eos;
-
- // Some constants from zlib.
- static final int Z_DEFLATED = 8;
- static final int HEAD_CRC = 0x02;
- static final int EXTRA_FIELD = 0x04;
- static final int ORIG_NAME = 0x08;
- static final int COMMENT = 0x10;
- static final int RESERVED = 0xe0;
}
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