/// <summary>
/// Parses the Next Option value
/// </summary>
/// <param name="buffer">The buffer containing the data</param>
/// <param name="position">The current position within the buffer</param>
/// <param name="remainingData">The amount of data remaining to be parsed</param>
/// <returns>The parsed TLV option</returns>
public static TLVOptionsData ParseNextOption(byte[] buffer, ref ushort position, ref long remainingData)
{
TLVOptionsData OptionsData = null;
long dataField = 0;
byte count = 0;
long fieldValue = VarInt.DecodeVarInt(buffer, ref position, out count);
WireType wireType = (WireType)(fieldValue & COAP_WIRE_TYPE_MASK);
long fieldNumber = fieldValue >> 3;
remainingData -= count;
switch (wireType)
{
case WireType.VARINT:
{
dataField = VarInt.DecodeVarInt(buffer, ref position, out count);
OptionsData = new TLVOptionsData(BitConverter.GetBytes(dataField), (byte)fieldNumber);
remainingData -= count;
break;
}
case WireType.I64_BIT:
{
byte[] byaData = new byte[sizeof(Int64)];
Array.Copy(buffer, position, byaData, 0, sizeof(Int64));
OptionsData = new TLVOptionsData(byaData, (byte)fieldNumber);
position += sizeof(Int64);
remainingData -= sizeof(Int64);
break;
}
case WireType.LENGTH_DELIMITED:
{
long lengthDelimitedLength = VarInt.DecodeVarInt(buffer, ref position, out count);
remainingData -= count;
byte[] byaData = new byte[lengthDelimitedLength];
Array.Copy(buffer, position, byaData, 0, lengthDelimitedLength);
OptionsData = new TLVOptionsData(byaData, (byte)fieldNumber);
position += (ushort)lengthDelimitedLength;
remainingData -= (ushort)lengthDelimitedLength;
break;
}
case WireType.I32_BIT:
{
byte[] byaData = new byte[sizeof(Int32)];
Array.Copy(buffer, position, byaData, 0, sizeof(Int32));
OptionsData = new TLVOptionsData(byaData, (byte)fieldNumber);
position += sizeof(Int32);
remainingData -= sizeof(Int32);
break;
}
default:
{
// deprecated or unknown wire type
// TODO - what should we do if we encounter one of these?
Debug.WriteLine("TLV.ParseNextOption() Warning: Unknown Wire Type detected");
break;
}
}
return(OptionsData);
}
/// <summary>
/// Parses the content of the buffer passed in and appends the data to the list
/// passed in.
/// </summary>
/// <param name="buffer">the packet data to be parsed</param>
/// <param name="TLVList">data structure that will hold the parsed data</param>
/// <param name="position">The starting positon of the TLV data</param>
// Revision History
// MM/DD/YY Who Version Issue# Description
// -------- --- ------- ------ -------------------------------------------
// 11/08/16 RCG Added so that this code can be shared with MUSE devices
// which have a different start position
public static void ParseTLVData(byte[] buffer, ref List <TLVData> TLVList, ushort position)
{
string TLVId = "";
long length;
long remainingData;
TLVOptionsData lastOption = null;
while (position < buffer.Length)
{
TLVData data = new TLVData();
byte count;
long varIntData = VarInt.DecodeVarInt(buffer, ref position, out count);
if (varIntData == VENDOR_DEFINED_TYPE)
{
// this is a vendor defined TLV
// +--------+--------+--------+--------+--------
// | 127 | IANAEN | Type | Length | Value…
// +--------+--------+--------+--------+--------
varIntData = VarInt.DecodeVarInt(buffer, ref position, out count);
if (varIntData == ITRON_IANAEN)
{
TLVId = "e1233.";
varIntData = VarInt.DecodeVarInt(buffer, ref position, out count);
TLVId += varIntData.ToString(CultureInfo.InvariantCulture);
}
}
else
{
// +--------+--------+--------
// | Type | Length | Value…
// +--------+--------+--------
TLVId = varIntData.ToString(CultureInfo.InvariantCulture);
}
data.TLVID = TLVId;
length = VarInt.DecodeVarInt(buffer, ref position, out count);
remainingData = length;
if (buffer.Length >= position + length)
{
// There has to be at least 2 bytes of data for us to parse - 1 byte for the tag/wire type and
// at least one byte of data
do
{
if (remainingData > 1)
{
// read and deal with the options
lastOption = ParseNextOption(buffer, ref position, ref remainingData);
if (lastOption != null)
{
data.Options.Add(lastOption);
}
}
} while (remainingData > 1 && lastOption != null);
TLVList.Add(data);
}
}
}
