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tools/openfst-1.6.7/include/fst/matcher-fst.h
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// See www.openfst.org for extensive documentation on this weighted
// finite-state transducer library.
//
// Class to add a matcher to an FST.
#ifndef FST_MATCHER_FST_H_
#define FST_MATCHER_FST_H_
#include <memory>
#include <string>
#include <fst/add-on.h>
#include <fst/const-fst.h>
#include <fst/lookahead-matcher.h>
namespace fst {
// Writeable matchers have the same interface as Matchers (as defined in
// matcher.h) along with the following additional methods:
//
// template <class F>
// class Matcher {
// public:
// using FST = F;
// ...
// using MatcherData = ...; // Initialization data.
//
// // Constructor with additional argument for external initialization data;
// // matcher increments its reference count on construction and decrements
// // the reference count, and deletes once the reference count has reached
// // zero.
// Matcher(const FST &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 also provide the following
// interface:
//
// class MatcherData {
// public:
// // Required copy constructor.
// MatcherData(const MatcherData &);
//
// // Required I/O methods.
// static MatcherData *Read(std::istream &istrm, const FstReadOptions &opts);
// bool Write(std::ostream &ostrm, const FstWriteOptions &opts) const;
// };
// Trivial (no-op) MatcherFst initializer functor.
template <class M>
class NullMatcherFstInit {
public:
using MatcherData = typename M::MatcherData;
using Data = AddOnPair<MatcherData, MatcherData>;
using Impl = internal::AddOnImpl<typename M::FST, Data>;
explicit NullMatcherFstInit(std::shared_ptr<Impl> *) {}
};
// Class adding a matcher to an FST type. Creates a new FST whose name is given
// by N. An optional functor Init can be used to initialize the FST. The Data
// template parameter allows the user to select the type of the add-on.
template <
class F, class M, const char *Name, class Init = NullMatcherFstInit<M>,
class Data = AddOnPair<typename M::MatcherData, typename M::MatcherData>>
class MatcherFst : public ImplToExpandedFst<internal::AddOnImpl<F, Data>> {
public:
using FST = F;
using Arc = typename FST::Arc;
using StateId = typename Arc::StateId;
using FstMatcher = M;
using MatcherData = typename FstMatcher::MatcherData;
using Impl = internal::AddOnImpl<FST, Data>;
using D = Data;
friend class StateIterator<MatcherFst<FST, FstMatcher, Name, Init, Data>>;
friend class ArcIterator<MatcherFst<FST, FstMatcher, Name, Init, Data>>;
MatcherFst() : ImplToExpandedFst<Impl>(std::make_shared<Impl>(FST(), Name)) {}
explicit MatcherFst(const FST &fst, std::shared_ptr<Data> data = nullptr)
: ImplToExpandedFst<Impl>(data ? CreateImpl(fst, Name, data)
: CreateDataAndImpl(fst, Name)) {}
explicit MatcherFst(const Fst<Arc> &fst)
: ImplToExpandedFst<Impl>(CreateDataAndImpl(fst, Name)) {}
// See Fst<>::Copy() for doc.
MatcherFst(const MatcherFst<FST, FstMatcher, Name, Init, Data> &fst,
bool safe = false)
: ImplToExpandedFst<Impl>(fst, safe) {}
// Get a copy of this MatcherFst. See Fst<>::Copy() for further doc.
MatcherFst<FST, FstMatcher, Name, Init, Data> *Copy(
bool safe = false) const override {
return new MatcherFst<FST, FstMatcher, Name, Init, Data>(*this, safe);
}
// Read a MatcherFst from an input stream; return nullptr on error
static MatcherFst<FST, M, Name, Init, Data> *Read(
std::istream &strm, const FstReadOptions &opts) {
auto *impl = Impl::Read(strm, opts);
return impl ? new MatcherFst<FST, FstMatcher, Name, Init, Data>(
std::shared_ptr<Impl>(impl))
: nullptr;
}
// Read a MatcherFst from a file; return nullptr on error
// Empty filename reads from standard input
static MatcherFst<FST, FstMatcher, Name, Init, Data> *Read(
const string &filename) {
auto *impl = ImplToExpandedFst<Impl>::Read(filename);
return impl ? new MatcherFst<FST, FstMatcher, Name, Init, Data>(
std::shared_ptr<Impl>(impl))
: nullptr;
}
bool Write(std::ostream &strm, const FstWriteOptions &opts) const override {
return GetImpl()->Write(strm, opts);
}
bool Write(const string &filename) const override {
return Fst<Arc>::WriteFile(filename);
}
void InitStateIterator(StateIteratorData<Arc> *data) const override {
return GetImpl()->InitStateIterator(data);
}
void InitArcIterator(StateId s, ArcIteratorData<Arc> *data) const override {
return GetImpl()->InitArcIterator(s, data);
}
FstMatcher *InitMatcher(MatchType match_type) const override {
return new FstMatcher(&GetFst(), match_type, GetSharedData(match_type));
}
const FST &GetFst() const { return GetImpl()->GetFst(); }
const Data *GetAddOn() const { return GetImpl()->GetAddOn(); }
std::shared_ptr<Data> GetSharedAddOn() const {
return GetImpl()->GetSharedAddOn();
}
const MatcherData *GetData(MatchType match_type) const {
const auto *data = GetAddOn();
return match_type == MATCH_INPUT ? data->First() : data->Second();
}
std::shared_ptr<MatcherData> GetSharedData(MatchType match_type) const {
const auto *data = GetAddOn();
return match_type == MATCH_INPUT ? data->SharedFirst()
: data->SharedSecond();
}
protected:
using ImplToFst<Impl, ExpandedFst<Arc>>::GetImpl;
static std::shared_ptr<Impl> CreateDataAndImpl(const FST &fst,
const string &name) {
FstMatcher imatcher(fst, MATCH_INPUT);
FstMatcher omatcher(fst, MATCH_OUTPUT);
return CreateImpl(fst, name,
std::make_shared<Data>(imatcher.GetSharedData(),
omatcher.GetSharedData()));
}
static std::shared_ptr<Impl> CreateDataAndImpl(const Fst<Arc> &fst,
const string &name) {
FST result(fst);
return CreateDataAndImpl(result, name);
}
static std::shared_ptr<Impl> CreateImpl(const FST &fst, const string &name,
std::shared_ptr<Data> data) {
auto impl = std::make_shared<Impl>(fst, name);
impl->SetAddOn(data);
Init init(&impl);
return impl;
}
explicit MatcherFst(std::shared_ptr<Impl> impl)
: ImplToExpandedFst<Impl>(impl) {}
private:
MatcherFst &operator=(const MatcherFst &) = delete;
};
// Specialization for MatcherFst.
template <class FST, class M, const char *Name, class Init>
class StateIterator<MatcherFst<FST, M, Name, Init>>
: public StateIterator<FST> {
public:
explicit StateIterator(const MatcherFst<FST, M, Name, Init> &fst)
: StateIterator<FST>(fst.GetImpl()->GetFst()) {}
};
// Specialization for MatcherFst.
template <class FST, class M, const char *Name, class Init>
class ArcIterator<MatcherFst<FST, M, Name, Init>> : public ArcIterator<FST> {
public:
using StateId = typename FST::Arc::StateId;
ArcIterator(const MatcherFst<FST, M, Name, Init> &fst,
typename FST::Arc::StateId s)
: ArcIterator<FST>(fst.GetImpl()->GetFst(), s) {}
};
// Specialization for MatcherFst.
template <class F, class M, const char *Name, class Init>
class Matcher<MatcherFst<F, M, Name, Init>> {
public:
using FST = MatcherFst<F, M, Name, Init>;
using Arc = typename F::Arc;
using Label = typename Arc::Label;
using StateId = typename Arc::StateId;
Matcher(const FST &fst, MatchType match_type)
: matcher_(fst.InitMatcher(match_type)) {}
Matcher(const Matcher<FST> &matcher) : matcher_(matcher.matcher_->Copy()) {}
Matcher<FST> *Copy() const { return new Matcher<FST>(*this); }
MatchType Type(bool test) const { return matcher_->Type(test); }
void SetState(StateId s) { matcher_->SetState(s); }
bool Find(Label label) { return matcher_->Find(label); }
bool Done() const { return matcher_->Done(); }
const Arc &Value() const { return matcher_->Value(); }
void Next() { matcher_->Next(); }
uint64 Properties(uint64 props) const { return matcher_->Properties(props); }
uint32 Flags() const { return matcher_->Flags(); }
private:
std::unique_ptr<M> matcher_;
};
// Specialization for MatcherFst.
template <class F, class M, const char *Name, class Init>
class LookAheadMatcher<MatcherFst<F, M, Name, Init>> {
public:
using FST = MatcherFst<F, M, Name, Init>;
using Arc = typename F::Arc;
using Label = typename Arc::Label;
using StateId = typename Arc::StateId;
using Weight = typename Arc::Weight;
LookAheadMatcher(const FST &fst, MatchType match_type)
: matcher_(fst.InitMatcher(match_type)) {}
LookAheadMatcher(const LookAheadMatcher<FST> &matcher, bool safe = false)
: matcher_(matcher.matcher_->Copy(safe)) {}
// General matcher methods.
LookAheadMatcher<FST> *Copy(bool safe = false) const {
return new LookAheadMatcher<FST>(*this, safe);
}
MatchType Type(bool test) const { return matcher_->Type(test); }
void SetState(StateId s) { matcher_->SetState(s); }
bool Find(Label label) { return matcher_->Find(label); }
bool Done() const { return matcher_->Done(); }
const Arc &Value() const { return matcher_->Value(); }
void Next() { matcher_->Next(); }
const FST &GetFst() const { return matcher_->GetFst(); }
uint64 Properties(uint64 props) const { return matcher_->Properties(props); }
uint32 Flags() const { return matcher_->Flags(); }
bool LookAheadLabel(Label label) const {
return matcher_->LookAheadLabel(label);
}
bool LookAheadFst(const Fst<Arc> &fst, StateId s) {
return matcher_->LookAheadFst(fst, s);
}
Weight LookAheadWeight() const { return matcher_->LookAheadWeight(); }
bool LookAheadPrefix(Arc *arc) const {
return matcher_->LookAheadPrefix(arc);
}
void InitLookAheadFst(const Fst<Arc> &fst, bool copy = false) {
matcher_->InitLookAheadFst(fst, copy);
}
private:
std::unique_ptr<M> matcher_;
};
// Useful aliases when using StdArc.
extern const char arc_lookahead_fst_type[];
using StdArcLookAheadFst =
MatcherFst<ConstFst<StdArc>,
ArcLookAheadMatcher<SortedMatcher<ConstFst<StdArc>>>,
arc_lookahead_fst_type>;
extern const char ilabel_lookahead_fst_type[];
extern const char olabel_lookahead_fst_type[];
constexpr auto ilabel_lookahead_flags =
kInputLookAheadMatcher | kLookAheadWeight | kLookAheadPrefix |
kLookAheadEpsilons | kLookAheadNonEpsilonPrefix;
constexpr auto olabel_lookahead_flags =
kOutputLookAheadMatcher | kLookAheadWeight | kLookAheadPrefix |
kLookAheadEpsilons | kLookAheadNonEpsilonPrefix;
using StdILabelLookAheadFst = MatcherFst<
ConstFst<StdArc>,
LabelLookAheadMatcher<SortedMatcher<ConstFst<StdArc>>,
ilabel_lookahead_flags, FastLogAccumulator<StdArc>>,
ilabel_lookahead_fst_type, LabelLookAheadRelabeler<StdArc>>;
using StdOLabelLookAheadFst = MatcherFst<
ConstFst<StdArc>,
LabelLookAheadMatcher<SortedMatcher<ConstFst<StdArc>>,
olabel_lookahead_flags, FastLogAccumulator<StdArc>>,
olabel_lookahead_fst_type, LabelLookAheadRelabeler<StdArc>>;
} // namespace fst
#endif // FST_MATCHER_FST_H_
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