/// <summary>
/// Decode input as an NDN-TLV LpPacket and set the fields of the lpPacket object.
/// </summary>
///
/// <param name="lpPacket">The LpPacket object whose fields are updated.</param>
/// <param name="input"></param>
/// <param name="copy">unchanged while the Blob values are used.</param>
/// <exception cref="EncodingException">For invalid encoding.</exception>
public override void decodeLpPacket(LpPacket lpPacket, ByteBuffer input, bool copy)
{
lpPacket.clear();
TlvDecoder decoder = new TlvDecoder(input);
int endOffset = decoder.readNestedTlvsStart(net.named_data.jndn.encoding.tlv.Tlv.LpPacket_LpPacket);
while (decoder.getOffset() < endOffset) {
// Imitate TlvDecoder.readTypeAndLength.
int fieldType = decoder.readVarNumber();
int fieldLength = decoder.readVarNumber();
int fieldEndOffset = decoder.getOffset() + fieldLength;
if (fieldEndOffset > input.limit())
throw new EncodingException(
"TLV length exceeds the buffer length");
if (fieldType == net.named_data.jndn.encoding.tlv.Tlv.LpPacket_Fragment) {
// Set the fragment to the bytes of the TLV value.
lpPacket.setFragmentWireEncoding(new Blob(decoder.getSlice(
decoder.getOffset(), fieldEndOffset), copy));
decoder.seek(fieldEndOffset);
// The fragment is supposed to be the last field.
break;
} else if (fieldType == net.named_data.jndn.encoding.tlv.Tlv.LpPacket_Nack) {
NetworkNack networkNack = new NetworkNack();
int code = (int) decoder.readOptionalNonNegativeIntegerTlv(
net.named_data.jndn.encoding.tlv.Tlv.LpPacket_NackReason, fieldEndOffset);
// The enum numeric values are the same as this wire format, so use as is.
if (code < 0
|| code == net.named_data.jndn.NetworkNack.Reason.NONE.getNumericType())
// This includes an omitted NackReason.
networkNack.setReason(net.named_data.jndn.NetworkNack.Reason.NONE);
else if (code == net.named_data.jndn.NetworkNack.Reason.CONGESTION.getNumericType())
networkNack.setReason(net.named_data.jndn.NetworkNack.Reason.CONGESTION);
else if (code == net.named_data.jndn.NetworkNack.Reason.DUPLICATE.getNumericType())
networkNack.setReason(net.named_data.jndn.NetworkNack.Reason.DUPLICATE);
else if (code == net.named_data.jndn.NetworkNack.Reason.NO_ROUTE.getNumericType())
networkNack.setReason(net.named_data.jndn.NetworkNack.Reason.NO_ROUTE);
else {
// Unrecognized reason.
networkNack.setReason(net.named_data.jndn.NetworkNack.Reason.OTHER_CODE);
networkNack.setOtherReasonCode(code);
}
lpPacket.addHeaderField(networkNack);
} else if (fieldType == net.named_data.jndn.encoding.tlv.Tlv.LpPacket_IncomingFaceId) {
IncomingFaceId incomingFaceId = new IncomingFaceId();
incomingFaceId.setFaceId(decoder
.readNonNegativeInteger(fieldLength));
lpPacket.addHeaderField(incomingFaceId);
} else {
// Unrecognized field type. The conditions for ignoring are here:
// http://redmine.named-data.net/projects/nfd/wiki/NDNLPv2
bool canIgnore = (fieldType >= net.named_data.jndn.encoding.tlv.Tlv.LpPacket_IGNORE_MIN
&& fieldType <= net.named_data.jndn.encoding.tlv.Tlv.LpPacket_IGNORE_MAX && (fieldType & 0x01) == 1);
if (!canIgnore)
throw new EncodingException(
"Did not get the expected TLV type");
// Ignore.
decoder.seek(fieldEndOffset);
}
decoder.finishNestedTlvs(fieldEndOffset);
}
decoder.finishNestedTlvs(endOffset);
}
