// matcher-fst.h
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Copyright 2005-2010 Google, Inc.
// Author: riley@google.com (Michael Riley)
//
// \file
// Class to add a matcher to an FST.
#ifndef FST_LIB_MATCHER_FST_FST_H__
#define FST_LIB_MATCHER_FST_FST_H__
#include <fst/add-on.h>
#include <fst/const-fst.h>
#include <fst/lookahead-matcher.h>
namespace fst {
// WRITABLE MATCHERS - these have the interface of Matchers (see
// matcher.h) and these additional methods:
//
// template <class F>
// class Matcher {
// public:
// typedef ... MatcherData; // Initialization data
// ...
// // Constructor with additional argument for external initialization
// // data; matcher increments its reference count on construction and
// // decrements the reference count, and if 0 deletes, on destruction.
// Matcher(const F &fst, MatchType type, MatcherData *data);
//
// // Returns pointer to initialization data that can be
// // passed to a Matcher constructor.
// MatcherData *GetData() const;
// };
// The matcher initialization data class must have the form:
// class MatcherData {
// public:
// // Required copy constructor.
// MatcherData(const MatcherData &);
// //
// // Required I/O methods.
// static MatcherData *Read(istream &istrm);
// bool Write(ostream &ostrm);
//
// // Required reference counting.
// int RefCount() const;
// int IncrRefCount();
// int DecrRefCount();
// };
// Default MatcherFst initializer - does nothing.
template <class M>
class NullMatcherFstInit {
public:
typedef AddOnPair<typename M::MatcherData, typename M::MatcherData> D;
typedef AddOnImpl<typename M::FST, D> Impl;
NullMatcherFstInit(Impl **) {}
};
// Class to add a matcher M to an Fst F. Creates a new Fst of type name N.
// Optional function object I can be used to initialize the Fst.
template <class F, class M, const char* N,
class I = NullMatcherFstInit<M> >
class MatcherFst
: public ImplToExpandedFst<
AddOnImpl<F,
AddOnPair<typename M::MatcherData,
typename M::MatcherData> > > {
public:
friend class StateIterator< MatcherFst<F, M, N, I> >;
friend class ArcIterator< MatcherFst<F, M, N, I> >;
typedef F FST;
typedef M FstMatcher;
typedef typename F::Arc Arc;
typedef typename Arc::StateId StateId;
typedef AddOnPair<typename M::MatcherData, typename M::MatcherData> D;
typedef AddOnImpl<F, D> Impl;
MatcherFst() : ImplToExpandedFst<Impl>(new Impl(F(), N)) {}
explicit MatcherFst(const F &fst)
: ImplToExpandedFst<Impl>(CreateImpl(fst, N)) {}
explicit MatcherFst(const Fst<Arc> &fst)
: ImplToExpandedFst<Impl>(CreateImpl(fst, N)) {}
// See Fst<>::Copy() for doc.
MatcherFst(const MatcherFst<F, M, N, I> &fst, bool safe = false)
: ImplToExpandedFst<Impl>(fst, safe) {}
// Get a copy of this MatcherFst. See Fst<>::Copy() for further doc.
virtual MatcherFst<F, M, N, I> *Copy(bool safe = false) const {
return new MatcherFst<F, M, N, I>(*this, safe);
}
// Read a MatcherFst from an input stream; return NULL on error
static MatcherFst<F, M, N, I> *Read(istream &strm,
const FstReadOptions &opts) {
Impl *impl = Impl::Read(strm, opts);
return impl ? new MatcherFst<F, M, N, I>(impl) : 0;
}
// Read a MatcherFst from a file; return NULL on error
// Empty filename reads from standard input
static MatcherFst<F, M, N, I> *Read(const string &filename) {
Impl *impl = ImplToExpandedFst<Impl>::Read(filename);
return impl ? new MatcherFst<F, M, N, I>(impl) : 0;
}
virtual bool Write(ostream &strm, const FstWriteOptions &opts) const {
return GetImpl()->Write(strm, opts);
}
virtual bool Write(const string &filename) const {
return Fst<Arc>::WriteFile(filename);
}
virtual void InitStateIterator(StateIteratorData<Arc> *data) const {
return GetImpl()->InitStateIterator(data);
}
virtual void InitArcIterator(StateId s, ArcIteratorData<Arc> *data) const {
return GetImpl()->InitArcIterator(s, data);
}
virtual M *InitMatcher(MatchType match_type) const {
return new M(GetFst(), match_type, GetData(match_type));
}
// Allows access to MatcherFst components.
Impl *GetImpl() const {
return ImplToFst<Impl, ExpandedFst<Arc> >::GetImpl();
}
F& GetFst() const { return GetImpl()->GetFst(); }
typename M::MatcherData *GetData(MatchType match_type) const {
D *data = GetImpl()->GetAddOn();
return match_type == MATCH_INPUT ? data->First() : data->Second();
}
private:
static Impl *CreateImpl(const F &fst, const string &name) {
M imatcher(fst, MATCH_INPUT);
M omatcher(fst, MATCH_OUTPUT);
D *data = new D(imatcher.GetData(), omatcher.GetData());
Impl *impl = new Impl(fst, name);
impl->SetAddOn(data);
I init(&impl);
data->DecrRefCount();
return impl;
}
static Impl *CreateImpl(const Fst<Arc> &fst, const string &name) {
F ffst(fst);
return CreateImpl(ffst, name);
}
explicit MatcherFst(Impl *impl) : ImplToExpandedFst<Impl>(impl) {}
// Makes visible to friends.
void SetImpl(Impl *impl, bool own_impl = true) {
ImplToFst< Impl, ExpandedFst<Arc> >::SetImpl(impl, own_impl);
}
void operator=(const MatcherFst<F, M, N, I> &fst); // disallow
};
// Specialization fo MatcherFst.
template <class F, class M, const char* N, class I>
class StateIterator< MatcherFst<F, M, N, I> > : public StateIterator<F> {
public:
explicit StateIterator(const MatcherFst<F, M, N, I> &fst) :
StateIterator<F>(fst.GetImpl()->GetFst()) {}
};
// Specialization for MatcherFst.
template <class F, class M, const char* N, class I>
class ArcIterator< MatcherFst<F, M, N, I> > : public ArcIterator<F> {
public:
ArcIterator(const MatcherFst<F, M, N, I> &fst, typename F::Arc::StateId s)
: ArcIterator<F>(fst.GetImpl()->GetFst(), s) {}
};
// Specialization for MatcherFst
template <class F, class M, const char* N, class I>
class Matcher< MatcherFst<F, M, N, I> > {
public:
typedef MatcherFst<F, M, N, I> FST;
typedef typename F::Arc Arc;
typedef typename Arc::StateId StateId;
typedef typename Arc::Label Label;
Matcher(const FST &fst, MatchType match_type) {
matcher_ = fst.InitMatcher(match_type);
}
Matcher(const Matcher<FST> &matcher) {
matcher_ = matcher.matcher_->Copy();
}
~Matcher() { delete matcher_; }
Matcher<FST> *Copy() const {
return new Matcher<FST>(*this);
}
MatchType Type(bool test) const { return matcher_->Type(test); }
void SetState(