mosesdecoder/moses/FactorCollection.h

116 lines
3.7 KiB
C++

// $Id$
/***********************************************************************
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
***********************************************************************/
#ifndef moses_FactorCollection_h
#define moses_FactorCollection_h
#ifdef WITH_THREADS
#include <boost/thread/shared_mutex.hpp>
#endif
#include "util/murmur_hash.hh"
#include <boost/unordered_set.hpp>
#include <functional>
#include <string>
#include "util/string_piece.hh"
#include "util/pool.hh"
#include "Factor.h"
namespace Moses
{
/** We don't want Factor to be copyable by anybody. But we also want to store
* it in an STL container. The solution is that Factor's copy constructor is
* private and friended to FactorFriend. The STL containers can delegate
* copying, so friending the container isn't sufficient. STL containers see
* FactorFriend's public copy constructor and everybody else sees Factor's
* private copy constructor.
*/
struct FactorFriend {
Factor in;
};
/** collection of factors
*
* All Factors in moses are accessed and created by a FactorCollection.
* By enforcing this strict creation processes (ie, forbidding factors
* from being created on the stack, etc), their memory addresses can
* be used as keys to uniquely identify them.
* Only 1 FactorCollection object should be created.
*/
class FactorCollection
{
friend std::ostream& operator<<(std::ostream&, const FactorCollection&);
struct HashFactor : public std::unary_function<const FactorFriend &, std::size_t> {
std::size_t operator()(const FactorFriend &factor) const {
return util::MurmurHashNative(factor.in.m_string.data(), factor.in.m_string.size());
}
};
struct EqualsFactor : public std::binary_function<const FactorFriend &, const FactorFriend &, bool> {
bool operator()(const FactorFriend &left, const FactorFriend &right) const {
return left.in.GetString() == right.in.GetString();
}
};
typedef boost::unordered_set<FactorFriend, HashFactor, EqualsFactor> Set;
Set m_set;
util::Pool m_string_backing;
static FactorCollection s_instance;
#ifdef WITH_THREADS
//reader-writer lock
mutable boost::shared_mutex m_accessLock;
#endif
size_t m_factorId; /**< unique, contiguous ids, starting from 0, for each factor */
//! constructor. only the 1 static variable can be created
FactorCollection()
:m_factorId(0)
{}
public:
static FactorCollection& Instance() {
return s_instance;
}
~FactorCollection();
/** returns a factor with the same direction, factorType and factorString.
* If a factor already exist in the collection, return the existing factor, if not create a new 1
*/
const Factor *AddFactor(const StringPiece &factorString);
// TODO: remove calls to this function, replacing them with the simpler AddFactor(factorString)
const Factor *AddFactor(FactorDirection /*direction*/, FactorType /*factorType*/, const StringPiece &factorString) {
return AddFactor(factorString);
}
TO_STRING();
};
}
#endif