/*
* Copyright (c) 2010, 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 "TwelveMonkeys" 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 OWNER 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.image;
import com.twelvemonkeys.lang.Validate;
import java.awt.image.DataBuffer;
import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.*;
import java.nio.channels.FileChannel;
/**
* A {@code DataBuffer} implementation that is backed by a memory mapped file.
* Memory will be allocated outside the normal JVM heap, allowing more efficient
* memory usage for large buffers.
*
* @author <a href="mailto:harald.kuhr@gmail.com">Harald Kuhr</a>
* @author last modified by $Author: haraldk$
* @version $Id: MappedFileBuffer.java,v 1.0 Jun 12, 2010 4:56:51 PM haraldk Exp$
*
* @see java.nio.channels.FileChannel#map(java.nio.channels.FileChannel.MapMode, long, long)
*/
public abstract class MappedFileBuffer extends DataBuffer {
private final Buffer buffer;
private MappedFileBuffer(final int type, final int size, final int numBanks) throws IOException {
super(type, Validate.isTrue(size >= 0, size, "Integer overflow for size: %d"), Validate.isTrue(numBanks >= 0, numBanks, "Number of banks must be positive"));
int componentSize = DataBuffer.getDataTypeSize(type) / 8;
// Create temp file to get a file handle to use for memory mapping
File tempFile = File.createTempFile(String.format("%s-", getClass().getSimpleName().toLowerCase()), ".tmp");
try {
RandomAccessFile raf = new RandomAccessFile(tempFile, "rw");
long length = ((long) size) * componentSize * numBanks;
raf.setLength(length);
FileChannel channel = raf.getChannel();
// Map entire file into memory, let OS virtual memory/paging do the heavy lifting
MappedByteBuffer byteBuffer = channel.map(FileChannel.MapMode.READ_WRITE, 0, length);
switch (type) {
case DataBuffer.TYPE_BYTE:
buffer = byteBuffer;
break;
case DataBuffer.TYPE_USHORT:
buffer = byteBuffer.asShortBuffer();
break;
case DataBuffer.TYPE_INT:
buffer = byteBuffer.asIntBuffer();
break;
default:
throw new IllegalArgumentException("Unsupported data type: " + type);
}
// According to the docs, we can safely close the channel and delete the file now
channel.close();
}
finally {
// NOTE: File can't be deleted right now on Windows, as the file is open. Let JVM clean up later
if (!tempFile.delete()) {
tempFile.deleteOnExit();
}
}
}
@Override
public String toString() {
return String.format("MappedFileBuffer: %s", buffer);
}
// TODO: Is throws IOException a good idea?
public static DataBuffer create(final int type, final int size, final int numBanks) throws IOException {
switch (type) {
case DataBuffer.TYPE_BYTE:
return new DataBufferByte(size, numBanks);
case DataBuffer.TYPE_USHORT:
return new DataBufferUShort(size, numBanks);
case DataBuffer.TYPE_INT:
return new DataBufferInt(size, numBanks);
default:
throw new IllegalArgumentException("Unsupported data type: " + type);
}
}
final static class DataBufferByte extends MappedFileBuffer {
private final ByteBuffer buffer;
public DataBufferByte(int size, int numBanks) throws IOException {
super(DataBuffer.TYPE_BYTE, size, numBanks);
buffer = (ByteBuffer) super.buffer;
}
@Override
public int getElem(int bank, int i) {
return buffer.get(bank * size + i) & 0xff;
}
@Override
public void setElem(int bank, int i, int val) {
buffer.put(bank * size + i, (byte) val);
}
}
final static class DataBufferUShort extends MappedFileBuffer {
private final ShortBuffer buffer;
public DataBufferUShort(int size, int numBanks) throws IOException {
super(DataBuffer.TYPE_USHORT, size, numBanks);
buffer = (ShortBuffer) super.buffer;
}
@Override
public int getElem(int bank, int i) {
return buffer.get(bank * size + i) & 0xffff;
}
@Override
public void setElem(int bank, int i, int val) {
buffer.put(bank * size + i, (short) val);
}
}
final static class DataBufferInt extends MappedFileBuffer {
private final IntBuffer buffer;
public DataBufferInt(int size, int numBanks) throws IOException {
super(DataBuffer.TYPE_INT, size, numBanks);
buffer = (IntBuffer) super.buffer;
}
@Override
public int getElem(int bank, int i) {
return buffer.get(bank * size + i);
}
@Override
public void setElem(int bank, int i, int val) {
buffer.put(bank * size + i, val);
}
}
}