mosesdecoder/moses/src/RuleTable/UTrieNode.h

/***********************************************************************
 Moses - statistical machine translation system
 Copyright (C) 2006-2012 University of Edinburgh
 
 This library is free software; you can redistribute it and/or
 modify it under the terms of the GNU Lesser General Public
 License as published by the Free Software Foundation; either
 version 2.1 of the License, or (at your option) any later version.
 
 This library 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
 Lesser General Public License for more details.
 
 You should have received a copy of the GNU Lesser General Public
 License along with this library; if not, write to the Free Software
 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
***********************************************************************/

#pragma once

#include "NonTerminal.h"
#include "RuleTable/Trie.h"
#include "TargetPhrase.h"
#include "TargetPhraseCollection.h"
#include "Terminal.h"
#include "Util.h"
#include "Word.h"

#include <boost/functional/hash.hpp>
#include <boost/unordered_map.hpp>
#include <boost/version.hpp>

#include <map>
#include <vector>

namespace Moses
{

class RuleTableUTrie;

class UTrieNode
{
 public:
  typedef std::vector<std::vector<Word> > LabelTable;
#if defined(BOOST_VERSION) && (BOOST_VERSION >= 104200)
  typedef boost::unordered_map<Word,
                               UTrieNode,
                               TerminalHasher,
                               TerminalEqualityPred> TerminalMap;

  typedef boost::unordered_map<std::vector<int>,
                               TargetPhraseCollection> LabelMap;
#else
  typedef std::map<Word, UTrieNode> TerminalMap;
  typedef std::map<std::vector<int>, TargetPhraseCollection> LabelMap;
#endif

  ~UTrieNode() { delete m_gapNode; }

  const LabelTable &GetLabelTable() const { return m_labelTable; }
  const LabelMap &GetLabelMap() const { return m_labelMap; }
  const TerminalMap &GetTerminalMap() const { return m_terminalMap; }

  const UTrieNode *GetNonTerminalChild() const { return m_gapNode; }

  UTrieNode *GetOrCreateTerminalChild(const Word &sourceTerm);
  UTrieNode *GetOrCreateNonTerminalChild(const Word &targetNonTerm);

  TargetPhraseCollection &GetOrCreateTargetPhraseCollection(
      const TargetPhrase &);

  bool IsLeaf() const { return m_terminalMap.empty() && m_gapNode == NULL; }

  bool HasRules() const { return !m_labelMap.empty(); }

  void Prune(size_t tableLimit);
  void Sort(size_t tableLimit);

 private:
  friend class RuleTableUTrie;

  UTrieNode() : m_gapNode(NULL) {}

  int InsertLabel(int i, const Word &w)
  {
    std::vector<Word> &inner = m_labelTable[i];
    for (size_t j = 0; j < inner.size(); ++j) {
      if (inner[j] == w) {
        return j;
      }
    }
    inner.push_back(w);
    return inner.size()-1;
  }

  LabelTable m_labelTable;
  LabelMap m_labelMap;
  TerminalMap m_terminalMap;
  UTrieNode *m_gapNode;
};

}  // namespace Moses