publisher: add LSDB dataset publishers

refs #2280

Change-Id: Ifb1920ef9b807610890b0d0a04f24141d39f011d
diff --git a/src/publisher/segment-publisher.hpp b/src/publisher/segment-publisher.hpp
new file mode 100644
index 0000000..cb311e9
--- /dev/null
+++ b/src/publisher/segment-publisher.hpp
@@ -0,0 +1,130 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014-2015,  Regents of the University of California,
+ *                           Arizona Board of Regents,
+ *                           Colorado State University,
+ *                           University Pierre & Marie Curie, Sorbonne University,
+ *                           Washington University in St. Louis,
+ *                           Beijing Institute of Technology,
+ *                           The University of Memphis.
+ *
+ * This file is part of NFD (Named Data Networking Forwarding Daemon).
+ * See AUTHORS.md for complete list of NFD authors and contributors.
+ *
+ * NFD 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.
+ *
+ * NFD 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
+ * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef NLSR_PUBLISHER_SEGMENT_PUBLISHER_HPP
+#define NLSR_PUBLISHER_SEGMENT_PUBLISHER_HPP
+
+#include <ndn-cxx/encoding/encoding-buffer.hpp>
+#include <ndn-cxx/security/key-chain.hpp>
+
+namespace nlsr {
+
+/** \brief provides a publisher of Status Dataset or other segmented octet stream
+ *  \sa http://redmine.named-data.net/projects/nfd/wiki/StatusDataset
+ */
+template <class FaceBase>
+class SegmentPublisher : ndn::noncopyable
+{
+public:
+  SegmentPublisher(FaceBase& face,
+                   const ndn::Name& prefix,
+                   ndn::KeyChain& keyChain,
+                   const ndn::time::milliseconds& freshnessPeriod = getDefaultFreshness())
+    : m_face(face)
+    , m_prefix(prefix)
+    , m_keyChain(keyChain)
+    , m_freshnessPeriod(freshnessPeriod)
+  {
+  }
+
+  virtual
+  ~SegmentPublisher()
+  {
+  }
+
+  static size_t
+  getMaxSegmentSize()
+  {
+    static const size_t MAX_SEGMENT_SIZE = ndn::MAX_NDN_PACKET_SIZE >> 1;
+    return MAX_SEGMENT_SIZE;
+  }
+
+  static constexpr ndn::time::milliseconds
+  getDefaultFreshness()
+  {
+    return ndn::time::milliseconds(1000);
+  }
+
+  void
+  publish()
+  {
+    ndn::EncodingBuffer buffer;
+    generate(buffer);
+
+    const uint8_t* rawBuffer = buffer.buf();
+    const uint8_t* segmentBegin = rawBuffer;
+    const uint8_t* end = rawBuffer + buffer.size();
+
+    ndn::Name segmentPrefix(m_prefix);
+    segmentPrefix.appendVersion();
+
+    uint64_t segmentNo = 0;
+    do {
+      const uint8_t* segmentEnd = segmentBegin + getMaxSegmentSize();
+      if (segmentEnd > end) {
+        segmentEnd = end;
+      }
+
+      ndn::Name segmentName(segmentPrefix);
+      segmentName.appendSegment(segmentNo);
+
+      ndn::shared_ptr<ndn::Data> data = ndn::make_shared<ndn::Data>(segmentName);
+      data->setContent(segmentBegin, segmentEnd - segmentBegin);
+      data->setFreshnessPeriod(m_freshnessPeriod);
+
+      segmentBegin = segmentEnd;
+      if (segmentBegin >= end) {
+        data->setFinalBlockId(segmentName[-1]);
+      }
+
+      publishSegment(data);
+      ++segmentNo;
+    } while (segmentBegin < end);
+  }
+
+protected:
+  /** \brief In a derived class, write the octets into outBuffer.
+   */
+  virtual size_t
+  generate(ndn::EncodingBuffer& outBuffer) = 0;
+
+private:
+  void
+  publishSegment(ndn::shared_ptr<ndn::Data>& data)
+  {
+    m_keyChain.sign(*data);
+    m_face.put(*data);
+  }
+
+private:
+  FaceBase& m_face;
+  const ndn::Name m_prefix;
+  ndn::KeyChain& m_keyChain;
+  const ndn::time::milliseconds m_freshnessPeriod;
+};
+
+} // namespace nlsr
+
+#endif // NLSR_PUBLISHER_SEGMENT_PUBLISHER_HPP