publisher: implement routing table dataset publisher

refs: #3631, #3634

Change-Id: I7e961fdd0857690bee65d2bdfa4cf3de90ccac06
diff --git a/src/tlv/nexthop.cpp b/src/tlv/nexthop.cpp
new file mode 100644
index 0000000..79b6e97
--- /dev/null
+++ b/src/tlv/nexthop.cpp
@@ -0,0 +1,136 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014-2018,  The University of Memphis,
+ *                           Regents of the University of California,
+ *                           Arizona Board of Regents.
+ *
+ * This file is part of NLSR (Named-data Link State Routing).
+ * See AUTHORS.md for complete list of NLSR authors and contributors.
+ *
+ * NLSR is free software: you can redistribute it and/or modify it under the terms
+ * of the GNU General Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later version.
+ *
+ * NLSR is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+ * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * NLSR, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ **/
+
+#include "nexthop.hpp"
+#include "tlv-nlsr.hpp"
+
+#include <ndn-cxx/util/concepts.hpp>
+#include <ndn-cxx/encoding/block-helpers.hpp>
+
+namespace nlsr {
+namespace tlv {
+
+BOOST_CONCEPT_ASSERT((ndn::WireEncodable<NextHop>));
+BOOST_CONCEPT_ASSERT((ndn::WireDecodable<NextHop>));
+static_assert(std::is_base_of<ndn::tlv::Error, NextHop::Error>::value,
+              "NextHop::Error must inherit from tlv::Error");
+
+NextHop::NextHop()
+  : m_cost(0)
+{
+}
+
+NextHop::NextHop(const ndn::Block& block)
+{
+  wireDecode(block);
+}
+
+template<ndn::encoding::Tag TAG>
+size_t
+NextHop::wireEncode(ndn::EncodingImpl<TAG>& block) const
+{
+  size_t totalLength = 0;
+
+  const uint8_t* doubleBytes = reinterpret_cast<const uint8_t*>(&m_cost);
+  totalLength += block.prependByteArrayBlock(ndn::tlv::nlsr::Double, doubleBytes, 8);
+
+  totalLength += block.prependByteArrayBlock(
+    ndn::tlv::nlsr::Uri, reinterpret_cast<const uint8_t*>(m_uri.c_str()), m_uri.size());
+
+  totalLength += block.prependVarNumber(totalLength);
+  totalLength += block.prependVarNumber(ndn::tlv::nlsr::NextHop);
+
+  return totalLength;
+}
+
+NDN_CXX_DECLARE_WIRE_ENCODE_INSTANTIATIONS(NextHop);
+
+template size_t
+NextHop::wireEncode<ndn::encoding::EncoderTag>(ndn::EncodingImpl<ndn::encoding::EncoderTag>& block) const;
+
+template size_t
+NextHop::wireEncode<ndn::encoding::EstimatorTag>(ndn::EncodingImpl<ndn::encoding::EstimatorTag>& block) const;
+
+const ndn::Block&
+NextHop::wireEncode() const
+{
+  if (m_wire.hasWire()) {
+    return m_wire;
+  }
+
+  ndn::EncodingEstimator estimator;
+  size_t estimatedSize = wireEncode(estimator);
+
+  ndn::EncodingBuffer buffer(estimatedSize, 0);
+  wireEncode(buffer);
+
+  m_wire = buffer.block();
+
+  return m_wire;
+}
+
+void
+NextHop::wireDecode(const ndn::Block& wire)
+{
+  m_uri = "";
+  m_cost = 0;
+
+  m_wire = wire;
+
+  if (m_wire.type() != ndn::tlv::nlsr::NextHop) {
+    std::stringstream error;
+    error << "Expected NextHop Block, but Block is of a different type: #"
+          << m_wire.type();
+    BOOST_THROW_EXCEPTION(Error(error.str()));
+  }
+
+  m_wire.parse();
+
+  ndn::Block::element_const_iterator val = m_wire.elements_begin();
+
+  if (val != m_wire.elements_end() && val->type() == ndn::tlv::nlsr::Uri) {
+    m_uri.assign(reinterpret_cast<const char*>(val->value()), val->value_size());
+    ++val;
+  }
+  else {
+    BOOST_THROW_EXCEPTION(Error("Missing required Uri field"));
+  }
+
+  if (val != val->elements_end() && val->type() == ndn::tlv::nlsr::Double) {
+    m_cost = *reinterpret_cast<const double*>(val->value());
+    ++val;
+  }
+  else {
+    BOOST_THROW_EXCEPTION(Error("HyperbolicCost: Missing required Double field"));
+  }
+}
+
+std::ostream&
+operator<<(std::ostream& os, const NextHop& nexthop)
+{
+  os << "NextHop("
+     << "Uri: " << nexthop.getUri() << ", "<< "Cost: " << nexthop.getCost() << ")" << std::endl;
+
+  return os;
+}
+
+} // namespace tlv
+} // namespace nlsr