private void writeRecordHeaderToMappedBuffer(RecordHeader header) {
mappedDataBuffer.position(header.getPosition());
mappedDataBuffer.putInt(header.getDataSize());
mappedDataBuffer.put(header.getFragmented());
if (header.isFragmented()) {
mappedDataBuffer.putInt(header.getNextPos());
}
}
/* (non-Javadoc)
* @see com.ongraphdb.store.DiskSore1#writeData(byte[], int)
*/
public int writeData(byte[] data, int blockSize) throws IOException {
RecordHeader header = new RecordHeader().setDataSize(data.length).setFragmented(false);
int recordSize = getRecordSize(blockSize, header);
header.setPosition(getNextPosition(recordSize));
try {
writeRecordHeader(header);
writeRecordData(header, data);
} catch (IOException e) {
// write to hole
throw e;
}
return header.getPosition();
}
/* (non-Javadoc)
* @see com.ongraphdb.store.DiskSore1#readData(int)
*/
public byte[] readData(int pos) throws IOException {
RecordHeader header = readRecordHeader(pos);
byte[] data = readRecordData(header);
if (header.isFragmented()) {
byte[] result, tailData;
tailData = readData(header.getNextPos());
result = new byte[data.length + tailData.length];
System.arraycopy(data, 0, result, 0, data.length);
System.arraycopy(tailData, 0, result, data.length, tailData.length);
return result;
}
return data;
}
private void writeRecordHeaderToChannel(RecordHeader header) throws IOException {
ByteBuffer buffer = ByteBuffer.allocate(header.getSize());
buffer.putInt(header.getDataSize());
buffer.put(header.getFragmented());
if (header.isFragmented()) {
buffer.putInt(header.getNextPos());
}
buffer.flip();
dataChannel.position(header.getPosition());
dataChannel.write(buffer);
}
private RecordHeader readRecordHeaderFromMappedBuffer(int pos) {
RecordHeader header = new RecordHeader();
mappedDataBuffer.position(pos);
header.setPosition(pos);
header.setDataSize(mappedDataBuffer.getInt());
header.setFragmented(mappedDataBuffer.get());
if (header.isFragmented()) {
header.setNextPos(mappedDataBuffer.getInt());
}
return header;
}
private RecordHeader readRecordHeaderFromChannel(int pos) throws IOException {
RecordHeader header = new RecordHeader();
header.setPosition(pos);
ByteBuffer buffer = ByteBuffer.allocate(RecordHeader.HEADER_BYTES);
dataChannel.position(pos);
dataChannel.read(buffer);
buffer.flip();
header.setDataSize(buffer.getInt());
header.setFragmented(buffer.get());
if (header.isFragmented()) {
header.setNextPos(buffer.getInt());
}
return header;
}
private void writeRecordDataToMappedBuffer(RecordHeader header, byte[] data) {
mappedDataBuffer.position(header.getPosition() + header.getSize());
mappedDataBuffer.put(data);
}
private void writeRecordDataToChannel(RecordHeader header, byte[] data) throws IOException {
ByteBuffer buffer = ByteBuffer.wrap(data);
dataChannel.position(header.getPosition() + header.getSize());
dataChannel.write(buffer);
dataChannel.force(false);
}
private byte[] readRecordDataFromMappedBuffer(RecordHeader header) {
byte[] data = new byte[header.getDataSize()];
mappedDataBuffer.position(header.getPosition() + header.getSize());
mappedDataBuffer.get(data);
return data;
}
private byte[] readRecordDataFromChannel(RecordHeader header) throws IOException {
ByteBuffer buffer = ByteBuffer.allocate(header.getDataSize());
dataChannel.position(header.getPosition() + header.getSize());
dataChannel.read(buffer);
return buffer.array();
}
private boolean isMapped(RecordHeader header) {
return dataMappedMemorySize > (header.getPosition() + header.getSize() + header.getDataSize());
}
protected int getRecordSize(int blockSize, RecordHeader header) {
return ((header.getSize() + header.getDataSize() + blockSize - 1) / blockSize) * blockSize;
}
/* (non-Javadoc)
* @see com.ongraphdb.store.DiskSore1#updateData(int, byte[], int)
*/
public void updateData(int pos, byte[] data, int blockSize) throws IOException {
RecordHeader oldHeader = readRecordHeader(pos);
RecordHeader newHeader =
new RecordHeader().setPosition(pos).setDataSize(data.length).setFragmented(false);
int oldRecordSize = getRecordSize(blockSize, oldHeader);
int newRecordSize = getRecordSize(blockSize, newHeader);
if (oldRecordSize >= newRecordSize) {
if (oldHeader.isFragmented() || (oldRecordSize - newRecordSize > blockSize)) {
// write tail to hole
// write rest blocks to hole
}
writeRecordHeader(newHeader);
writeRecordData(newHeader, data);
} else {
newHeader.setFragmented(true);
newHeader.setDataSize(oldRecordSize - newHeader.getSize());
byte[] headData = new byte[newHeader.getDataSize()];
byte[] tailData = new byte[data.length - newHeader.getDataSize()];
System.arraycopy(data, 0, headData, 0, newHeader.getDataSize());
System.arraycopy(data, headData.length, tailData, 0, tailData.length);
RecordHeader newTailHeader =
new RecordHeader().setDataSize(tailData.length).setFragmented(false);
int newRecordTailSize = getRecordSize(blockSize, newTailHeader);
if (oldHeader.isFragmented()) {
RecordHeader oldHeaderTail = readRecordHeader(oldHeader.getNextPos());
int oldRecordTailSize = getRecordSize(blockSize, oldHeaderTail);
if (oldRecordTailSize >= newRecordSize) {
newTailHeader.setPosition(oldHeaderTail.getPosition());
// write rest blocks to hole
} else {
// write tail to hole
newTailHeader.setPosition(getNextPosition(newRecordTailSize));
}
} else {
newTailHeader.setPosition(getNextPosition(newRecordTailSize));
}
newHeader.setNextPos(newTailHeader.getPosition());
writeRecordHeader(newHeader);
writeRecordData(newHeader, headData);
writeRecordHeader(newTailHeader);
writeRecordData(newTailHeader, tailData);
}
}
