155 lines
3.4 KiB
Java
155 lines
3.4 KiB
Java
// 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. */
|
|
|
|
package java.util.zip;
|
|
|
|
import java.io.InputStream;
|
|
import java.io.IOException;
|
|
|
|
/**
|
|
* @author Tom Tromey
|
|
* @date May 17, 1999
|
|
*/
|
|
|
|
/* Written using on-line Java Platform 1.2 API Specification
|
|
* and JCL book.
|
|
* Believed complete and correct.
|
|
*/
|
|
|
|
public class GZIPInputStream extends InflaterInputStream
|
|
{
|
|
public static final int GZIP_MAGIC = 0x8b1f;
|
|
|
|
public void close () throws IOException
|
|
{
|
|
// Nothing to do here.
|
|
super.close();
|
|
}
|
|
|
|
public GZIPInputStream (InputStream istream) throws IOException
|
|
{
|
|
this (istream, 512);
|
|
}
|
|
|
|
private final int eof_read () throws IOException
|
|
{
|
|
int r = in.read();
|
|
if (r == -1)
|
|
throw new ZipException ("gzip header corrupted");
|
|
return r & 0xff;
|
|
}
|
|
|
|
public GZIPInputStream (InputStream istream, int readsize)
|
|
throws IOException
|
|
{
|
|
super (istream, new Inflater (true), readsize);
|
|
|
|
// 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 ();
|
|
}
|
|
|
|
public int read (byte[] buf, int off, int len) throws IOException
|
|
{
|
|
if (eos)
|
|
return -1;
|
|
int r = super.read(buf, off, len);
|
|
if (r == -1)
|
|
{
|
|
eos = true;
|
|
int header_crc = read4 ();
|
|
if (crc.getValue() != header_crc)
|
|
throw new ZipException ("corrupted gzip file");
|
|
// Read final `ISIZE' field.
|
|
// FIXME: should we check this length?
|
|
read4 ();
|
|
return -1;
|
|
}
|
|
crc.update(buf, off, r);
|
|
return r;
|
|
}
|
|
|
|
private final int read4 () 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);
|
|
}
|
|
|
|
// 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;
|
|
}
|