mirror of git://gcc.gnu.org/git/gcc.git
253 lines
6.8 KiB
Java
253 lines
6.8 KiB
Java
/* 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., 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.InputStream;
|
|
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
|
|
* @since JDK 1.1
|
|
*/
|
|
public class GZIPInputStream
|
|
extends InflaterInputStream
|
|
{
|
|
/**
|
|
* The magic number found at the start of a GZIP stream.
|
|
*/
|
|
public static final int GZIP_MAGIC = 0x8b1f;
|
|
|
|
static final int Z_DEFLATED = 8;
|
|
|
|
/**
|
|
* 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;
|
|
|
|
/**
|
|
* 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
|
|
{
|
|
this(in, 4096);
|
|
}
|
|
|
|
/**
|
|
* 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(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);
|
|
if (magic != GZIP_MAGIC)
|
|
throw new ZipException("gzip header corrupted");
|
|
|
|
int method = eof_read();
|
|
int flags = eof_read();
|
|
// Test from zlib.
|
|
if (method != Z_DEFLATED || (flags & RESERVED) != 0)
|
|
throw new ZipException("gzip header corrupted");
|
|
|
|
// Discard time, xflags, OS code.
|
|
for (int i = 0; i < 6; ++i)
|
|
eof_read();
|
|
|
|
// Skip the extra field.
|
|
if ((flags & EXTRA_FIELD) != 0)
|
|
{
|
|
int len = eof_read() | (eof_read() << 8);
|
|
while (len-- != 0)
|
|
eof_read();
|
|
}
|
|
|
|
if ((flags & ORIG_NAME) != 0)
|
|
{
|
|
while (true)
|
|
{
|
|
int c = eof_read();
|
|
if (c == 0)
|
|
break;
|
|
}
|
|
}
|
|
|
|
if ((flags & COMMENT) != 0)
|
|
{
|
|
while (true)
|
|
{
|
|
int c = eof_read();
|
|
if (c == 0)
|
|
break;
|
|
}
|
|
}
|
|
|
|
if ((flags & HEAD_CRC) != 0)
|
|
{
|
|
// FIXME: consider checking CRC of the header.
|
|
eof_read();
|
|
eof_read();
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
/**
|
|
* 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, offset, len);
|
|
if (r == -1)
|
|
{
|
|
eos = true;
|
|
|
|
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 - crc mismatch");
|
|
int isize = read4(tmp, 4);
|
|
if (inf.getTotalOut() != isize)
|
|
throw new ZipException("corrupted gzip file - size mismatch");
|
|
return -1;
|
|
}
|
|
crc.update(buf, offset, r);
|
|
return r;
|
|
}
|
|
|
|
private final int read4(byte[] buf, int offset) throws IOException
|
|
{
|
|
return (((buf[offset + 3] & 0xFF) << 24) + ((buf[offset + 2] & 0xFF) << 16)
|
|
+ ((buf[offset + 1] & 0xFF) << 8) + (buf[offset] & 0xFF));
|
|
}
|
|
}
|