@Override
public void visit(LwM2mObject object) {
LOG.trace("Encoding object instances {} into TLV", object);
Tlv[] tlvs = null;
ObjectModel objectModel = model.getObjectModel(object.getId());
if (objectModel != null && !objectModel.multiple) {
// single instance object, the instance is level is not needed
tlvs = encodeResources(object.getInstances().get(0).getResources().values());
} else {
tlvs = new Tlv[object.getInstances().size()];
int i = 0;
for (Entry<Integer, LwM2mObjectInstance> instance : object.getInstances().entrySet()) {
Tlv[] resources = encodeResources(instance.getValue().getResources().values());
tlvs[i] = new Tlv(TlvType.OBJECT_INSTANCE, resources, null, instance.getKey());
i++;
}
}
try {
out.write(TlvEncoder.encode(tlvs).array());
} catch (IOException e) {
throw new RuntimeException(e);
}
}
@Override
public void visit(LwM2mResource resource) {
LOG.trace("Encoding resource {} into TLV", resource);
Tlv rTlv = encodeResource(resource);
try {
out.write(TlvEncoder.encode(new Tlv[] {rTlv}).array());
} catch (IOException e) {
throw new RuntimeException(e);
}
}
@Override
public void visit(LwM2mObjectInstance instance) {
LOG.trace("Encoding object instance {} into TLV", instance);
// The instance is encoded as an array of resource TLVs.
Tlv[] rTlvs = encodeResources(instance.getResources().values());
try {
out.write(TlvEncoder.encode(rTlvs).array());
} catch (IOException e) {
throw new RuntimeException(e);
}
}
/** Encodes an array of TLV. */
public static ByteBuffer encode(Tlv[] tlvs) {
int size = 0;
LOG.trace("start");
for (Tlv tlv : tlvs) {
int length = tlvEncodedLength(tlv);
size += tlvEncodedSize(tlv, length);
LOG.trace("tlv size : {}", size);
}
LOG.trace("done, size : {}", size);
ByteBuffer b = ByteBuffer.allocate(size);
b.order(ByteOrder.BIG_ENDIAN);
for (Tlv tlv : tlvs) {
encode(tlv, b);
}
b.flip();
return b;
}
private static void encode(Tlv tlv, ByteBuffer b) {
int length;
length = tlvEncodedLength(tlv);
int typeByte;
switch (tlv.getType()) {
case OBJECT_INSTANCE:
typeByte = 0b00_000000;
break;
case RESOURCE_INSTANCE:
typeByte = 0b01_000000;
break;
case MULTIPLE_RESOURCE:
typeByte = 0b10_000000;
break;
case RESOURCE_VALUE:
// encode the value
typeByte = 0b11_000000;
break;
default:
throw new IllegalArgumentException("unknown TLV type : '" + tlv.getType() + "'");
}
// encode identifier length
typeByte |= (tlv.getIdentifier() < MAX_LENGTH_8BIT) ? 0b00_0000 : 0b10_0000;
// type of length
if (length < 8) {
typeByte |= length;
} else if (length < MAX_LENGTH_8BIT) {
typeByte |= 0b0000_1000;
} else if (length < MAX_LENGTH_16BIT) {
typeByte |= 0b0001_0000;
} else {
typeByte |= 0b0001_1000;
}
// fill the buffer
b.put((byte) typeByte);
if (tlv.getIdentifier() < MAX_LENGTH_8BIT) {
b.put((byte) tlv.getIdentifier());
} else {
b.putShort((short) tlv.getIdentifier());
}
// write length
if (length >= 8) {
if (length < MAX_LENGTH_8BIT) {
b.put((byte) length);
} else if (length < MAX_LENGTH_16BIT) {
b.putShort((short) length);
} else {
int msb = (length & 0xFF_00_00) >> 16;
b.put((byte) msb);
b.putShort((short) (length & 0xFF_FF));
typeByte |= 0b0001_1000;
}
}
switch (tlv.getType()) {
case RESOURCE_VALUE:
case RESOURCE_INSTANCE:
b.put(tlv.getValue());
break;
default:
for (Tlv child : tlv.getChildren()) {
encode(child, b);
}
break;
}
}
