table: move PIT iterator to a separate file

This commit only moves code around and renames variables.
There's no functional change.

refs #3164

Change-Id: Icb6b249cc0c07fcfe42f7a6d6987de31285566e7
diff --git a/daemon/table/pit-iterator.hpp b/daemon/table/pit-iterator.hpp
new file mode 100644
index 0000000..061e077
--- /dev/null
+++ b/daemon/table/pit-iterator.hpp
@@ -0,0 +1,86 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014-2016,  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 NFD_DAEMON_TABLE_PIT_ITERATOR_HPP
+#define NFD_DAEMON_TABLE_PIT_ITERATOR_HPP
+
+#include "name-tree.hpp"
+#include "pit-entry.hpp"
+
+namespace nfd {
+namespace pit {
+
+/** \brief PIT iterator
+ */
+class Iterator : public std::iterator<std::forward_iterator_tag, const Entry>
+{
+public:
+  Iterator();
+
+  /** \brief constructor
+   *  \param ntIt a name tree iterator that visits name tree entries with one or more PIT entries
+   */
+  explicit
+  Iterator(const NameTree::const_iterator& ntIt);
+
+  const Entry&
+  operator*() const
+  {
+    return *this->operator->();
+  }
+
+  shared_ptr<Entry>
+  operator->() const
+  {
+    return m_ntIt->getPitEntries().at(m_iPitEntry);
+  }
+
+  Iterator&
+  operator++();
+
+  Iterator
+  operator++(int);
+
+  bool
+  operator==(const Iterator& other) const
+  {
+    return m_ntIt == other.m_ntIt && m_iPitEntry == other.m_iPitEntry;
+  }
+
+  bool
+  operator!=(const Iterator& other) const
+  {
+    return !this->operator==(other);
+  }
+
+private:
+  NameTree::const_iterator m_ntIt; ///< current name tree entry
+  size_t m_iPitEntry; ///< current PIT entry within m_ntIt->getPitEntries()
+};
+
+} // namespace pit
+} // namespace nfd
+
+#endif // NFD_DAEMON_TABLE_PIT_ITERATOR_HPP