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// $Id$
// vim:tabstop=2
/***********************************************************************
Moses - factored phrase-based language decoder
Copyright (C) 2006 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 <map>
#include <vector>
#include <iterator>
#include <utility>
#include <ostream>
#include "Word.h"
#include "TargetPhraseCollection.h"
#include <boost/functional/hash.hpp>
#include <boost/unordered_map.hpp>
#include <boost/version.hpp>
namespace Moses
{
class PhraseDictionarySCFG;
class TerminalHasher
{
public:
// Generate a hash value for a word representing a terminal. It's
// assumed that the same subset of factors will be active for all words
// that are hashed.
size_t operator()(const Word & t) const {
size_t seed = 0;
for (size_t i = 0; i < MAX_NUM_FACTORS; ++i) {
const Factor * f = t[i];
if (f) {
boost::hash_combine(seed, *f);
}
}
return seed;
}
};
class TerminalEqualityPred
{
public:
// Equality predicate for comparing words representing terminals. As
// with the hasher, it's assumed that all words will have the same
// subset of active factors.
bool operator()(const Word & t1, const Word & t2) const {
for (size_t i = 0; i < MAX_NUM_FACTORS; ++i) {
const Factor * f1 = t1[i];
const Factor * f2 = t2[i];
if (f1 && f1->Compare(*f2)) {
return false;
}
}
return true;
}
};
class NonTerminalMapKeyHasher
{
public:
size_t operator()(const std::pair<Word, Word> & k) const {
// Assumes that only the first factor of each Word is relevant.
const Word & w1 = k.first;
const Word & w2 = k.second;
const Factor * f1 = w1[0];
const Factor * f2 = w2[0];
size_t seed = 0;
boost::hash_combine(seed, *f1);
boost::hash_combine(seed, *f2);
return seed;
}
};
class NonTerminalMapKeyEqualityPred
{
public:
bool operator()(const std::pair<Word, Word> & k1,
const std::pair<Word, Word> & k2) const {
// Compare first non-terminal of each key. Assumes that for Words
// representing non-terminals only the first factor is relevant.
{
const Word & w1 = k1.first;
const Word & w2 = k2.first;
const Factor * f1 = w1[0];
const Factor * f2 = w2[0];
if (f1->Compare(*f2)) {
return false;
}
}
// Compare second non-terminal of each key.
{
const Word & w1 = k1.second;
const Word & w2 = k2.second;
const Factor * f1 = w1[0];
const Factor * f2 = w2[0];
if (f1->Compare(*f2)) {
return false;
}
}
return true;
}
};
/** One node of the PhraseDictionarySCFG structure
*/
class PhraseDictionaryNodeSCFG
{
public:
typedef std::pair<Word, Word> NonTerminalMapKey;
#if defined(BOOST_VERSION) && (BOOST_VERSION >= 104200)
typedef boost::unordered_map<Word,
PhraseDictionaryNodeSCFG,
TerminalHasher,
TerminalEqualityPred> TerminalMap;
typedef boost::unordered_map<NonTerminalMapKey,
PhraseDictionaryNodeSCFG,
NonTerminalMapKeyHasher,
NonTerminalMapKeyEqualityPred> NonTerminalMap;
#else
typedef std::map<Word, PhraseDictionaryNodeSCFG> TerminalMap;
typedef std::map<NonTerminalMapKey, PhraseDictionaryNodeSCFG> NonTerminalMap;
#endif
private:
friend std::ostream& operator<<(std::ostream&, const PhraseDictionarySCFG&);
// only these classes are allowed to instantiate this class
friend class PhraseDictionarySCFG;
friend class std::map<Word, PhraseDictionaryNodeSCFG>;
protected:
TerminalMap m_sourceTermMap;
NonTerminalMap m_nonTermMap;
TargetPhraseCollection *m_targetPhraseCollection;
PhraseDictionaryNodeSCFG()
:m_targetPhraseCollection(NULL)
{}
public:
virtual ~PhraseDictionaryNodeSCFG();
bool IsLeaf() const {
return m_sourceTermMap.empty() && m_nonTermMap.empty();
}
void Prune(size_t tableLimit);
void Sort(size_t tableLimit);
PhraseDictionaryNodeSCFG *GetOrCreateChild(const Word &sourceTerm);
PhraseDictionaryNodeSCFG *GetOrCreateChild(const Word &sourceNonTerm, const Word &targetNonTerm);
const PhraseDictionaryNodeSCFG *GetChild(const Word &sourceTerm) const;
const PhraseDictionaryNodeSCFG *GetChild(const Word &sourceNonTerm, const Word &targetNonTerm) const;
const TargetPhraseCollection *GetTargetPhraseCollection() const {
return m_targetPhraseCollection;
}
TargetPhraseCollection &GetOrCreateTargetPhraseCollection() {
if (m_targetPhraseCollection == NULL)
m_targetPhraseCollection = new TargetPhraseCollection();
return *m_targetPhraseCollection;
}
const NonTerminalMap & GetNonTerminalMap() const {
return m_nonTermMap;
}
void Clear();
TO_STRING();
};
std::ostream& operator<<(std::ostream&, const PhraseDictionaryNodeSCFG&);
}
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