/*
*
* Copyright 1990-2008 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 only, as published by the Free Software Foundation.
*
* This program 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 version 2 for more details (a copy is
* included at /legal/license.txt).
*
* You should have received a copy of the GNU General Public License
* version 2 along with this work; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
* Clara, CA 95054 or visit www.sun.com if you need additional
* information or have any questions.
*
*/
package java.util.zip;
import java.io.FilterInputStream;
import java.io.InputStream;
import java.io.IOException;
import java.io.EOFException;
import sun.io.Markable;
import sun.io.MarkableReader;
/**
* This class implements a stream filter for uncompressing data in the
* "deflate" compression format. It is also used as the basis for other
* decompression filters, such as GZIPInputStream.
* NOTE: <B>java.util.zip.GZIPInputStream</B> is found in J2ME CDC profiles
* such as J2ME Foundation Profile.
*
* @see Inflater
* @version 1.28, 02/02/00
* @author David Connelly
*/
public
class InflaterInputStream extends FilterInputStream {
/**
* Decompressor for this stream.
*/
protected Inflater inf;
/**
* Input buffer for decompression.
*/
protected byte[] buf;
/**
* Length of input buffer.
*/
protected int len;
private boolean closed = false;
// this flag is set to true after EOF has reached
private boolean reachEOF = false;
private MarkableReader reader;
/**
* Check to make sure that this stream has not been closed
*/
private void ensureOpen() throws IOException {
if (closed) {
throw new IOException("Stream closed");
}
}
/**
* Creates a new input stream with the specified decompressor and
* buffer size.
* @param in the input stream
* @param inf the decompressor ("inflater")
* @param size the input buffer size
* @exception IllegalArgumentException if size is <= 0
*/
public InflaterInputStream(InputStream in, Inflater inf, int size) {
super(in);
if (in == null || inf == null) {
throw new NullPointerException();
} else if (size <= 0) {
throw new IllegalArgumentException("buffer size <= 0");
}
this.inf = inf;
reader = new MarkableReader(new NativeReader());
buf = new byte[size];
}
/**
* Creates a new input stream with the specified decompressor and a
* default buffer size.
* @param in the input stream
* @param inf the decompressor ("inflater")
*/
public InflaterInputStream(InputStream in, Inflater inf) {
this(in, inf, 512);
}
boolean usesDefaultInflater = false;
/**
* Creates a new input stream with a default decompressor and buffer size.
* @param in the input stream
*/
public InflaterInputStream(InputStream in) {
this(in, new Inflater());
usesDefaultInflater = true;
}
private byte[] singleByteBuf = new byte[1];
/**
* Reads a byte of uncompressed data. This method will block until
* enough input is available for decompression.
* @return the byte read, or -1 if end of compressed input is reached
* @exception IOException if an I/O error has occurred
*/
public int read() throws IOException {
ensureOpen();
return read(singleByteBuf, 0, 1) == -1 ? -1 : singleByteBuf[0] & 0xff;
}
/**
* Reads uncompressed data into an array of bytes. This method will
* block until some input can be decompressed.
* @param b the buffer into which the data is read
* @param off the start offset of the data
* @param len the maximum number of bytes read
* @return the actual number of bytes read, or -1 if the end of the
* compressed input is reached or a preset dictionary is needed
* @exception ZipException if a ZIP format error has occurred
* @exception IOException if an I/O error has occurred
*/
public int read(byte[] b, int off, int len) throws IOException {
return reader.read(b, off, len);
}
private class NativeReader implements Markable {
public int readNative(byte[] b, int off, int len) throws IOException {
ensureOpen();
try {
int bytesRead = 0;
while (len > 0) {
int n = inf.inflate(b, off, len);
if (n == 0) {
if (inf.finished() || inf.needsDictionary()) {
reachEOF = true;
if (bytesRead > 0) {
return bytesRead;
} else {
return -1;
}
}
if (inf.needsInput()) {
fill();
}
}
bytesRead += n;
off += n;
len -= n;
}
return bytesRead;
} catch (DataFormatException e) {
String s = e.getMessage();
throw new ZipException(s != null ? s : "Invalid ZLIB data format");
}
}
}
/**
* Returns 0 after EOF has reached, otherwise always return 1.
* <p>
* Programs should not count on this method to return the actual number
* of bytes that could be read without blocking.
*
* @return 1 before EOF and 0 after EOF.
* @exception IOException if an I/O error occurs.
*
*/
public int available() throws IOException {
ensureOpen();
if (reachEOF) {
return 0;
} else {
return 1;
}
}
private byte[] b = new byte[512];
/**
* Skips specified number of bytes of uncompressed data.
* @param n the number of bytes to skip
* @return the actual number of bytes skipped.
* @exception IOException if an I/O error has occurred
* @exception IllegalArgumentException if n < 0
*/
public long skip(long n) throws IOException {
if (n < 0) {
throw new IllegalArgumentException("negative skip length");
}
ensureOpen();
int max = (int)Math.min(n, Integer.MAX_VALUE);
int total = 0;
while (total < max) {
int len = max - total;
if (len > b.length) {
len = b.length;
}
len = read(b, 0, len);
if (len == -1) {
reachEOF = true;
break;
}
total += len;
}
return total;
}
/**
* Closes the input stream.
* @exception IOException if an I/O error has occurred
*/
public void close() throws IOException {
if (!closed) {
if (usesDefaultInflater)
inf.end();
in.close();
closed = true;
}
}
/**
* Fills input buffer with more data to decompress.
* @exception IOException if an I/O error has occurred
*/
protected void fill() throws IOException {
ensureOpen();
len = in.read(buf, 0, buf.length);
if (len == -1) {
throw new EOFException("Unexpected end of ZLIB input stream");
}
inf.setInput(buf, 0, len);
}
/**
* Marks the current position in this input stream. A subsequent call to
* the <code>reset</code> method repositions this stream at the last marked
* position so that subsequent reads re-read the same bytes.
*
* <p> The <code>readlimit</code> arguments tells this input stream to
* allow that many bytes to be read before the mark position gets
* invalidated.
*
* <p> The general contract of <code>mark</code> is that, if the method
* <code>markSupported</code> returns <code>true</code>, the stream somehow
* remembers all the bytes read after the call to <code>mark</code> and
* stands ready to supply those same bytes again if and whenever the method
* <code>reset</code> is called. However, the stream is not required to
* remember any data at all if more than <code>readlimit</code> bytes are
* read from the stream before <code>reset</code> is called.
*
* <p> The <code>mark</code> method of <code>InputStream</code> does
* nothing.
*
* @param readlimit the maximum limit of bytes that can be read before
* the mark position becomes invalid.
* @see java.io.InputStream#reset()
*/
public synchronized void mark(int readlimit) {
reader.mark(readlimit);
}
/**
* Repositions this stream to the position at the time the
* <code>mark</code> method was last called on this input stream.
*
* <p> The general contract of <code>reset</code> is:
*
* <p><ul>
*
* <li> If the method <code>markSupported</code> returns
* <code>true</code>, then:
*
* <ul><li> If the method <code>mark</code> has not been called since
* the stream was created, or the number of bytes read from the stream
* since <code>mark</code> was last called is larger than the argument
* to <code>mark</code> at that last call, then an
* <code>IOException</code> might be thrown.
*
* <li> If such an <code>IOException</code> is not thrown, then the
* stream is reset to a state such that all the bytes read since the
* most recent call to <code>mark</code> (or since the start of the
* file, if <code>mark</code> has not been called) will be resupplied
* to subsequent callers of the <code>read</code> method, followed by
* any bytes that otherwise would have been the next input data as of
* the time of the call to <code>reset</code>. </ul>
*
* <li> If the method <code>markSupported</code> returns
* <code>false</code>, then:
*
* <ul><li> The call to <code>reset</code> may throw an
* <code>IOException</code>.
*
* <li> If an <code>IOException</code> is not thrown, then the stream
* is reset to a fixed state that depends on the particular type of the
* input stream and how it was created. The bytes that will be supplied
* to subsequent callers of the <code>read</code> method depend on the
* particular type of the input stream. </ul></ul>
*
* <p> The method <code>reset</code> for class <code>InputStream</code>
* does nothing and always throws an <code>IOException</code>.
*
* @exception IOException if this stream has not been marked or if the
* mark has been invalidated.
* @see java.io.InputStream#mark(int)
* @see java.io.IOException
*/
public synchronized void reset() throws IOException {
reader.reset();
}
/**
* Tests if this input stream supports the <code>mark</code> and
* <code>reset</code> methods. Whether or not <code>mark</code> and
* <code>reset</code> are supported is an invariant property of a
* particular input stream instance. The <code>markSupported</code> method
* of <code>InputStream</code> returns <code>false</code>.
*
* @return <code>true</code> if this stream instance supports the mark
* and reset methods; <code>false</code> otherwise.
* @see java.io.InputStream#mark(int)
* @see java.io.InputStream#reset()
*/
public boolean markSupported() {
return reader.markSupported();
}
}