RandomAccessStream.java
/*
* Copyright (c) 2008, Harald Kuhr
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* * Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.twelvemonkeys.io;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.EOFException;
import java.io.IOException;
/**
* A data stream that is both readable and writable, much like a
* {@code RandomAccessFile}, except it may be backed by something other than a file.
*
* @see java.io.RandomAccessFile
*
* @author <a href="mailto:harald.kuhr@gmail.com">Harald Kuhr</a>
* @author last modified by $Author: haku $
* @version $Id: //depot/branches/personal/haraldk/twelvemonkeys/release-2/twelvemonkeys-core/src/main/java/com/twelvemonkeys/io/RandomAccessStream.java#3 $
*/
public abstract class RandomAccessStream implements Seekable, DataInput, DataOutput {
// TODO: Use a RandomAcceessFile as backing in impl, probably
// TODO: Create an in-memory implementation too?
// TODO: Package private SeekableDelegate?
// TODO: Both read and write must update stream position
//private int position = -1;
/** This random access stream, wrapped in an {@code InputStream} */
SeekableInputStream inputView = null;
/** This random access stream, wrapped in an {@code OutputStream} */
SeekableOutputStream outputView = null;
// TODO: Create an Input and an Output interface matching InputStream and OutputStream?
public int read() throws IOException {
try {
return readByte() & 0xff;
}
catch (EOFException e) {
return -1;
}
}
public int read(final byte[] pBytes, final int pOffset, final int pLength) throws IOException {
if (pBytes == null) {
throw new NullPointerException("bytes == null");
}
else if ((pOffset < 0) || (pOffset > pBytes.length) || (pLength < 0) ||
((pOffset + pLength) > pBytes.length) || ((pOffset + pLength) < 0)) {
throw new IndexOutOfBoundsException();
}
else if (pLength == 0) {
return 0;
}
// Special case, allready at EOF
int c = read();
if (c == -1) {
return -1;
}
// Otherwise, read as many as bytes as possible
pBytes[pOffset] = (byte) c;
int i = 1;
try {
for (; i < pLength; i++) {
c = read();
if (c == -1) {
break;
}
pBytes[pOffset + i] = (byte) c;
}
}
catch (IOException ignore) {
// Ignore exception, just return length
}
return i;
}
public final int read(byte[] pBytes) throws IOException {
return read(pBytes, 0, pBytes != null ? pBytes.length : 1);
}
/**
* Returns an input view of this {@code RandomAccessStream}.
* Invoking this method several times, will return the same object.
* <p>
* <em>Note that read access is NOT synchronized.</em>
* </p>
*
* @return a {@code SeekableInputStream} reading from this stream
*/
public final SeekableInputStream asInputStream() {
if (inputView == null) {
inputView = new InputStreamView(this);
}
return inputView;
}
/**
* Returns an output view of this {@code RandomAccessStream}.
* Invoking this method several times, will return the same object.
* <p>
* <em>Note that write access is NOT synchronized.</em>
* </p>
*
* @return a {@code SeekableOutputStream} writing to this stream
*/
public final SeekableOutputStream asOutputStream() {
if (outputView == null) {
outputView = new OutputStreamView(this);
}
return outputView;
}
static final class InputStreamView extends SeekableInputStream {
// TODO: Consider adding synchonization (on stream) for all operations
// TODO: Is is a good thing that close/flush etc works on stream?
// - Or should it rather just work on the views?
// - Allow multiple views?
final private RandomAccessStream mStream;
public InputStreamView(RandomAccessStream pStream) {
if (pStream == null) {
throw new IllegalArgumentException("stream == null");
}
mStream = pStream;
}
public boolean isCached() {
return mStream.isCached();
}
public boolean isCachedFile() {
return mStream.isCachedFile();
}
public boolean isCachedMemory() {
return mStream.isCachedMemory();
}
protected void closeImpl() throws IOException {
mStream.close();
}
protected void flushBeforeImpl(long pPosition) throws IOException {
mStream.flushBefore(pPosition);
}
protected void seekImpl(long pPosition) throws IOException {
mStream.seek(pPosition);
}
public int read() throws IOException {
return mStream.read();
}
@Override
public int read(byte pBytes[], int pOffset, int pLength) throws IOException {
return mStream.read(pBytes, pOffset, pLength);
}
}
static final class OutputStreamView extends SeekableOutputStream {
// TODO: Consider adding synchonization (on stream) for all operations
// TODO: Is is a good thing that close/flush etc works on stream?
// - Or should it rather just work on the views?
// - Allow multiple views?
final private RandomAccessStream mStream;
public OutputStreamView(RandomAccessStream pStream) {
if (pStream == null) {
throw new IllegalArgumentException("stream == null");
}
mStream = pStream;
}
public boolean isCached() {
return mStream.isCached();
}
public boolean isCachedFile() {
return mStream.isCachedFile();
}
public boolean isCachedMemory() {
return mStream.isCachedMemory();
}
protected void closeImpl() throws IOException {
mStream.close();
}
protected void flushBeforeImpl(long pPosition) throws IOException {
mStream.flushBefore(pPosition);
}
protected void seekImpl(long pPosition) throws IOException {
mStream.seek(pPosition);
}
public void write(int pByte) throws IOException {
mStream.write(pByte);
}
@Override
public void write(byte pBytes[], int pOffset, int pLength) throws IOException {
mStream.write(pBytes, pOffset, pLength);
}
}
}