[ndnSIM] How to add additional std::vector<std::string> type field in Interest packet

Mudasir Qazi mudasirqazi00 at gmail.com
Sat May 19 00:54:15 PDT 2018

I need to add and an Integer and std::vector<std::string> type additional
fields in the Interest packet. I have done following steps to do so:
1. Added private fields (say: m_MyInteger and m_MyVector) in *interest.hpp*
file and write necessary getters, setters and helper functions to
manipulate these private members
2. Added MyVector = 40002 and MyInteger = 40003 in the enum in* tlv.hpp*
3. Added following code blocks in wireEncode method in *interest.cpp*
//for MyVector
std::vector<std::string> myTempVector = this->getMyVector();
    totalLength += encoder.prependByteArray(
    totalLength += encoder.prependVarNumber(sizeof(myTempVector));
    totalLength += encoder.prependVarNumber(tlv::MyVector);

//for MyInteger
int myTempInt = this->getMyInteger();
    totalLength += encoder.prependByteArray(
            reinterpret_cast<uint8_t*>(&myTempInt), sizeof(myTempInt));
    totalLength += encoder.prependVarNumber(sizeof(myTempInt));
    totalLength += encoder.prependVarNumber(tlv::MyInteger);

4. Added following code blocks in wireDecode method in *interest.cpp*
//for MyVector
val = m_wire.find(tlv::MyVector);
if (val == m_wire.elements_end()) {
    BOOST_THROW_EXCEPTION(Error("MyVector element is missing"));
std::vector<std::string> myTemVector;
if (val->value_size() != sizeof(myTemVector)) {
    BOOST_THROW_EXCEPTION(Error("myTemVector element is malformed"));
std::memcpy(&myTemVector, val->value(), sizeof(myTemVector));
m_MyVector = myTemVector;

//for MyInteger
val = m_wire.find(tlv::MyInteger);
if (val == m_wire.elements_end()) {
    BOOST_THROW_EXCEPTION(Error("MyInteger element is missing"));
uint32_t myTmpInteger = 0;
if (val->value_size() != sizeof(myTmpInteger)) {
    BOOST_THROW_EXCEPTION(Error("myTmpInteger element is malformed"));
std::memcpy(&myTmpInteger, val->value(), sizeof(myTmpInteger));
m_MyInteger = myTmpInteger;

5. I need to create a copy of Interest from an existing Interest (say:
existingInterest), so I'm using this way to create an Interest:
auto myInterest = std::make_shared<Interest>(existingInterest.wireEncode());

*Problem:* I'm following these 1-to-5 steps in order to add an Integer and
a std::vector<std::string> fields in Interest packet but it gives an error
on *wireDecode* while decoding MyVector field and simulation stops and
terminates. But it does not give error on MyInteger field. Am I doing it
right? Am I missing something? Please help me solving this I'm stuck on
this point from many days.

Mudasir Qazi
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