/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code 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. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code 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 in the LICENSE file that
* accompanied this code).
*
* 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package jdk.nio.zipfs;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.ClosedChannelException;
import java.nio.channels.NonWritableChannelException;
import java.nio.channels.SeekableByteChannel;
import java.util.Arrays;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
public class ByteArrayChannel implements SeekableByteChannel {
private final ReadWriteLock rwlock = new ReentrantReadWriteLock();
private byte buf[];
/*
* The current position of this channel.
*/
private int pos;
/*
* The index that is one greater than the last valid byte in the channel.
*/
private int last;
private boolean closed;
private boolean readonly;
/*
* Creates a {@code ByteArrayChannel} with size {@code sz}.
*/
ByteArrayChannel(int sz, boolean readonly) {
this.buf = new byte[sz];
this.pos = this.last = 0;
this.readonly = readonly;
}
/*
* Creates a ByteArrayChannel with its 'pos' at 0 and its 'last' at buf's end.
* Note: no defensive copy of the 'buf', used directly.
*/
ByteArrayChannel(byte[] buf, boolean readonly) {
this.buf = buf;
this.pos = 0;
this.last = buf.length;
this.readonly = readonly;
}
@Override
public boolean isOpen() {
return !closed;
}
@Override
public long position() throws IOException {
beginRead();
try {
ensureOpen();
return pos;
} finally {
endRead();
}
}
@Override
public SeekableByteChannel position(long pos) throws IOException {
beginWrite();
try {
ensureOpen();
if (pos < 0 || pos >= Integer.MAX_VALUE)
throw new IllegalArgumentException("Illegal position " + pos);
this.pos = Math.min((int)pos, last);
return this;
} finally {
endWrite();
}
}
@Override
public int read(ByteBuffer dst) throws IOException {
beginWrite();
try {
ensureOpen();
if (pos == last)
return -1;
int n = Math.min(dst.remaining(), last - pos);
dst.put(buf, pos, n);
pos += n;
return n;
} finally {
endWrite();
}
}
@Override
public SeekableByteChannel truncate(long size) throws IOException {
if (readonly)
throw new NonWritableChannelException();
ensureOpen();
throw new UnsupportedOperationException();
}
@Override
public int write(ByteBuffer src) throws IOException {
if (readonly)
throw new NonWritableChannelException();
beginWrite();
try {
ensureOpen();
int n = src.remaining();
ensureCapacity(pos + n);
src.get(buf, pos, n);
pos += n;
if (pos > last) {
last = pos;
}
return n;
} finally {
endWrite();
}
}
@Override
public long size() throws IOException {
beginRead();
try {
ensureOpen();
return last;
} finally {
endRead();
}
}
@Override
public void close() throws IOException {
if (closed)
return;
beginWrite();
try {
closed = true;
buf = null;
pos = 0;
last = 0;
} finally {
endWrite();
}
}
/**
* Creates a newly allocated byte array. Its size is the current
* size of this channel and the valid contents of the buffer
* have been copied into it.
*
* @return the current contents of this channel, as a byte array.
*/
public byte[] toByteArray() {
beginRead();
try {
// avoid copy if last == bytes.length?
return Arrays.copyOf(buf, last);
} finally {
endRead();
}
}
private void ensureOpen() throws IOException {
if (closed)
throw new ClosedChannelException();
}
private final void beginWrite() {
rwlock.writeLock().lock();
}
private final void endWrite() {
rwlock.writeLock().unlock();
}
private final void beginRead() {
rwlock.readLock().lock();
}
private final void endRead() {
rwlock.readLock().unlock();
}
private void ensureCapacity(int minCapacity) {
// overflow-conscious code
if (minCapacity - buf.length > 0) {
grow(minCapacity);
}
}
/**
* The maximum size of array to allocate.
* Some VMs reserve some header words in an array.
* Attempts to allocate larger arrays may result in
* OutOfMemoryError: Requested array size exceeds VM limit
*/
private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
/**
* Increases the capacity to ensure that it can hold at least the
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