utils/trie/trie-with-policy.hpp

/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/**
 * Copyright (c) 2011-2015  Regents of the University of California.
 *
 * This file is part of ndnSIM. See AUTHORS for complete list of ndnSIM authors and
 * contributors.
 *
 * ndnSIM 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.
 *
 * ndnSIM 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
 * ndnSIM, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
 **/

#ifndef TRIE_WITH_POLICY_H_
#define TRIE_WITH_POLICY_H_

/// @cond include_hidden

#include "trie.hpp"

namespace ns3 {
namespace ndn {
namespace ndnSIM {

template<typename FullKey, typename PayloadTraits, typename PolicyTraits>
class trie_with_policy {
public:
  typedef trie<FullKey, PayloadTraits, typename PolicyTraits::policy_hook_type> parent_trie;

  typedef typename parent_trie::iterator iterator;
  typedef typename parent_trie::const_iterator const_iterator;

  typedef typename PolicyTraits::
    template policy<trie_with_policy<FullKey, PayloadTraits, PolicyTraits>, parent_trie,
                    typename PolicyTraits::template container_hook<parent_trie>::type>::type
      policy_container;

  inline trie_with_policy(size_t bucketSize = 1, size_t bucketIncrement = 1)
    : trie_(name::Component(), bucketSize, bucketIncrement)
    , policy_(*this)
  {
  }

  inline std::pair<iterator, bool>
  insert(const FullKey& key, typename PayloadTraits::insert_type payload)
  {
    std::pair<iterator, bool> item = trie_.insert(key, payload);

    if (item.second) // real insert
    {
      bool ok = policy_.insert(s_iterator_to(item.first));
      if (!ok) {
        item.first->erase(); // cannot insert
        return std::make_pair(end(), false);
      }
    }
    else {
      return std::make_pair(s_iterator_to(item.first), false);
    }

    return item;
  }

  inline void
  erase(const FullKey& key)
  {
    iterator foundItem, lastItem;
    bool reachLast;
    std::tie(foundItem, reachLast, lastItem) = trie_.find(key);

    if (!reachLast || lastItem->payload() == PayloadTraits::empty_payload)
      return; // nothing to invalidate

    erase(lastItem);
  }

  inline void
  erase(iterator node)
  {
    if (node == end())
      return;

    policy_.erase(s_iterator_to(node));
    node->erase(); // will do cleanup here
  }

  inline void
  clear()
  {
    policy_.clear();
    trie_.clear();
  }

  template<typename Modifier>
  bool
  modify(iterator position, Modifier mod)
  {
    if (position == end())
      return false;
    if (position->payload() == PayloadTraits::empty_payload)
      return false;

    mod(*position->payload());
    policy_.update(position);
    return true;
  }

  /**
   * @brief Find a node that has the exact match with the key
   */
  inline iterator
  find_exact(const FullKey& key)
  {
    iterator foundItem, lastItem;
    bool reachLast;
    std::tie(foundItem, reachLast, lastItem) = trie_.find(key);

    if (!reachLast || lastItem->payload() == PayloadTraits::empty_payload)
      return end();

    return lastItem;
  }

  /**
   * @brief Find a node that has the longest common prefix with key (FIB/PIT lookup)
   */
  inline iterator
  longest_prefix_match(const FullKey& key)
  {
    iterator foundItem, lastItem;
    bool reachLast;
    std::tie(foundItem, reachLast, lastItem) = trie_.find(key);
    if (foundItem != trie_.end()) {
      policy_.lookup(s_iterator_to(foundItem));
    }
    return foundItem;
  }

  /**
   * @brief Find a node that has the longest common prefix with key (FIB/PIT lookup)
   */
  template<class Predicate>
  inline iterator
  longest_prefix_match_if(const FullKey& key, Predicate pred)
  {
    iterator foundItem, lastItem;
    bool reachLast;
    std::tie(foundItem, reachLast, lastItem) = trie_.find_if(key, pred);
    if (foundItem != trie_.end()) {
      policy_.lookup(s_iterator_to(foundItem));
    }
    return foundItem;
  }

  // /**
  //  * @brief Const version of the longest common prefix match
  //  * (semi-const, because there could be update of the policy anyways)
  //  */
  // inline const_iterator
  // longest_prefix_match (const FullKey &key) const
  // {
  //   return static_cast<trie_with_policy*> (this)->longest_prefix_match (key);
  // }

  /**
   * @brief Find a node that has prefix at least as the key (cache lookup)
   */
  inline iterator
  deepest_prefix_match(const FullKey& key)
  {
    iterator foundItem, lastItem;
    bool reachLast;
    std::tie(foundItem, reachLast, lastItem) = trie_.find(key);

    // guard in case we don't have anything in the trie
    if (lastItem == trie_.end())
      return trie_.end();

    if (reachLast) {
      if (foundItem == trie_.end()) {
        foundItem = lastItem->find(); // should be something
      }
      policy_.lookup(s_iterator_to(foundItem));
      return foundItem;
    }
    else { // couldn't find a node that has prefix at least as key
      return trie_.end();
    }
  }

  /**
   * @brief Find a node that has prefix at least as the key
   */
  template<class Predicate>
  inline iterator
  deepest_prefix_match_if(const FullKey& key, Predicate pred)
  {
    iterator foundItem, lastItem;
    bool reachLast;
    std::tie(foundItem, reachLast, lastItem) = trie_.find(key);

    // guard in case we don't have anything in the trie
    if (lastItem == trie_.end())
      return trie_.end();

    if (reachLast) {
      foundItem = lastItem->find_if(pred); // may or may not find something
      if (foundItem == trie_.end()) {
        return trie_.end();
      }
      policy_.lookup(s_iterator_to(foundItem));
      return foundItem;
    }
    else { // couldn't find a node that has prefix at least as key
      return trie_.end();
    }
  }

  /**
   * @brief Find a node that has prefix at least as the key
   *
   * This version of find checks predicate for the next level and if
   * predicate is True, returns first deepest match available
   */
  template<class Predicate>
  inline iterator
  deepest_prefix_match_if_next_level(const FullKey& key, Predicate pred)
  {
    iterator foundItem, lastItem;
    bool reachLast;
    std::tie(foundItem, reachLast, lastItem) = trie_.find(key);

    // guard in case we don't have anything in the trie
    if (lastItem == trie_.end())
      return trie_.end();

    if (reachLast) {
      foundItem = lastItem->find_if_next_level(pred); // may or may not find something
      if (foundItem == trie_.end()) {
        return trie_.end();
      }
      policy_.lookup(s_iterator_to(foundItem));
      return foundItem;
    }
    else { // couldn't find a node that has prefix at least as key
      return trie_.end();
    }
  }

  iterator
  end() const
  {
    return 0;
  }

  const parent_trie&
  getTrie() const
  {
    return trie_;
  }

  parent_trie&
  getTrie()
  {
    return trie_;
  }

  const policy_container&
  getPolicy() const
  {
    return policy_;
  }

  policy_container&
  getPolicy()
  {
    return policy_;
  }

  static inline iterator
  s_iterator_to(typename parent_trie::iterator item)
  {
    if (item == 0)
      return 0;
    else
      return &(*item);
  }

private:
  parent_trie trie_;
  mutable policy_container policy_;
};

} // ndnSIM
} // ndn
} // ns3

/// @endcond

#endif // TRIE_WITH_POLICY_H_