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diff --git a/kaldi_io/src/tools/openfst/include/fst/edit-fst.h b/kaldi_io/src/tools/openfst/include/fst/edit-fst.h new file mode 100644 index 0000000..bd33b9d --- /dev/null +++ b/kaldi_io/src/tools/openfst/include/fst/edit-fst.h @@ -0,0 +1,779 @@ + +// 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: dbikel@google.com (Dan Bikel) +// +// An \ref Fst implementation that allows non-destructive edit operations on an +// existing fst. + +#ifndef FST_LIB_EDIT_FST_H_ +#define FST_LIB_EDIT_FST_H_ + +#include <vector> +using std::vector; + +#include <fst/cache.h> + +#include <tr1/unordered_map> +using std::tr1::unordered_map; +using std::tr1::unordered_multimap; + +namespace fst { + +// The EditFst class enables non-destructive edit operations on a wrapped +// ExpandedFst. The implementation uses copy-on-write semantics at the node +// level: if a user has an underlying fst on which he or she wants to perform a +// relatively small number of edits (read: mutations), then this implementation +// will copy the edited node to an internal MutableFst and perform any edits in +// situ on that copied node. This class supports all the methods of MutableFst +// except for DeleteStates(const vector<StateId> &); thus, new nodes may also be +// added, and one may add transitions from existing nodes of the wrapped fst to +// new nodes. +// +// N.B.: The documentation for Fst::Copy(true) says that its behavior is +// undefined if invoked on an fst that has already been accessed. This class +// requires that the Fst implementation it wraps provides consistent, reliable +// behavior when its Copy(true) method is invoked, where consistent means +// the graph structure, graph properties and state numbering and do not change. +// VectorFst and CompactFst, for example, are both well-behaved in this regard. + +// The EditFstData class is a container for all mutable data for EditFstImpl; +// also, this class provides most of the actual implementation of what EditFst +// does (that is, most of EditFstImpl's methods delegate to methods in this, the +// EditFstData class). Instances of this class are reference-counted and can be +// shared between otherwise independent EditFstImpl instances. This scheme +// allows EditFstImpl to implement the thread-safe, copy-on-write semantics +// required by Fst::Copy(true). +// +// template parameters: +// A the type of arc to use +// WrappedFstT the type of fst wrapped by the EditFst instance that +// this EditFstData instance is backing +// MutableFstT the type of mutable fst to use internally for edited states; +// crucially, MutableFstT::Copy(false) *must* yield an fst that is +// thread-safe for reading (VectorFst, for example, has this property) +template <typename A, + typename WrappedFstT = ExpandedFst<A>, + typename MutableFstT = VectorFst<A> > +class EditFstData { + public: + typedef A Arc; + typedef typename A::Weight Weight; + typedef typename A::StateId StateId; + typedef typename unordered_map<StateId, StateId>::const_iterator + IdMapIterator; + typedef typename unordered_map<StateId, Weight>::const_iterator + FinalWeightIterator; + + + EditFstData() : num_new_states_(0) { + SetEmptyAndDeleteKeysForInternalMaps(); + } + + EditFstData(const EditFstData &other) : + edits_(other.edits_), + external_to_internal_ids_(other.external_to_internal_ids_), + edited_final_weights_(other.edited_final_weights_), + num_new_states_(other.num_new_states_) { + } + + ~EditFstData() { + } + + static EditFstData<A, WrappedFstT, MutableFstT> *Read(istream &strm, + const FstReadOptions &opts); + + bool Write(ostream &strm, const FstWriteOptions &opts) const { + // Serialize all private data members of this class. + FstWriteOptions edits_opts(opts); + edits_opts.write_header = true; // Force writing contained header. + edits_.Write(strm, edits_opts); + WriteType(strm, external_to_internal_ids_); + WriteType(strm, edited_final_weights_); + WriteType(strm, num_new_states_); + if (!strm) { + LOG(ERROR) << "EditFstData::Write: write failed: " << opts.source; + return false; + } + return true; + } + + int RefCount() const { return ref_count_.count(); } + int IncrRefCount() { return ref_count_.Incr(); } + int DecrRefCount() { return ref_count_.Decr(); } + + StateId NumNewStates() const { + return num_new_states_; + } + + // accessor methods for the fst holding edited states + StateId EditedStart() const { + return edits_.Start(); + } + + Weight Final(StateId s, const WrappedFstT *wrapped) const { + FinalWeightIterator final_weight_it = GetFinalWeightIterator(s); + if (final_weight_it == NotInFinalWeightMap()) { + IdMapIterator it = GetEditedIdMapIterator(s); + return it == NotInEditedMap() ? + wrapped->Final(s) : edits_.Final(it->second); + } + else { + return final_weight_it->second; + } + } + + size_t NumArcs(StateId s, const WrappedFstT *wrapped) const { + IdMapIterator it = GetEditedIdMapIterator(s); + return it == NotInEditedMap() ? + wrapped->NumArcs(s) : edits_.NumArcs(it->second); + } + + size_t NumInputEpsilons(StateId s, const WrappedFstT *wrapped) const { + IdMapIterator it = GetEditedIdMapIterator(s); + return it == NotInEditedMap() ? + wrapped->NumInputEpsilons(s) : + edits_.NumInputEpsilons(it->second); + } + + size_t NumOutputEpsilons(StateId s, const WrappedFstT *wrapped) const { + IdMapIterator it = GetEditedIdMapIterator(s); + return it == NotInEditedMap() ? + wrapped->NumOutputEpsilons(s) : + edits_.NumOutputEpsilons(it->second); + } + + void SetEditedProperties(uint64 props, uint64 mask) { + edits_.SetProperties(props, mask); + } + + // non-const MutableFst operations + + // Sets the start state for this fst. + void SetStart(StateId s) { + edits_.SetStart(s); + } + + // Sets the final state for this fst. + Weight SetFinal(StateId s, Weight w, const WrappedFstT *wrapped) { + Weight old_weight = Final(s, wrapped); + IdMapIterator it = GetEditedIdMapIterator(s); + // if we haven't already edited state s, don't add it to edited_ (which can + // be expensive if s has many transitions); just use the + // edited_final_weights_ map + if (it == NotInEditedMap()) { + edited_final_weights_[s] = w; + } + else { + edits_.SetFinal(GetEditableInternalId(s, wrapped), w); + } + return old_weight; + } + + // Adds a new state to this fst, initially with no arcs. + StateId AddState(StateId curr_num_states) { + StateId internal_state_id = edits_.AddState(); + StateId external_state_id = curr_num_states; + external_to_internal_ids_[external_state_id] = internal_state_id; + num_new_states_++; + return external_state_id; + } + + // Adds the specified arc to the specified state of this fst. + const A *AddArc(StateId s, const Arc &arc, const WrappedFstT *wrapped) { + StateId internal_id = GetEditableInternalId(s, wrapped); + + size_t num_arcs = edits_.NumArcs(internal_id); + ArcIterator<MutableFstT> arc_it(edits_, internal_id); + const A *prev_arc = NULL; + if (num_arcs > 0) { + // grab the final arc associated with this state in edits_ + arc_it.Seek(num_arcs - 1); + prev_arc = &(arc_it.Value()); + } + edits_.AddArc(internal_id, arc); + return prev_arc; + } + + void DeleteStates() { + edits_.DeleteStates(); + num_new_states_ = 0; + external_to_internal_ids_.clear(); + edited_final_weights_.clear(); + } + + // Removes all but the first n outgoing arcs of the specified state. + void DeleteArcs(StateId s, size_t n, const WrappedFstT *wrapped) { + edits_.DeleteArcs(GetEditableInternalId(s, wrapped), n); + } + + // Removes all outgoing arcs from the specified state. + void DeleteArcs(StateId s, const WrappedFstT *wrapped) { + edits_.DeleteArcs(GetEditableInternalId(s, wrapped)); + } + + // end methods for non-const MutableFst operations + + // Provides information for the generic arc iterator. + void InitArcIterator(StateId s, ArcIteratorData<Arc> *data, + const WrappedFstT *wrapped) const { + IdMapIterator id_map_it = GetEditedIdMapIterator(s); + if (id_map_it == NotInEditedMap()) { + VLOG(3) << "EditFstData::InitArcIterator: iterating on state " + << s << " of original fst"; + wrapped->InitArcIterator(s, data); + } else { + VLOG(2) << "EditFstData::InitArcIterator: iterating on edited state " + << s << " (internal state id: " << id_map_it->second << ")"; + edits_.InitArcIterator(id_map_it->second, data); + } + } + + // Provides information for the generic mutable arc iterator. + void InitMutableArcIterator(StateId s, MutableArcIteratorData<A> *data, + const WrappedFstT *wrapped) { + data->base = + new MutableArcIterator<MutableFstT>(&edits_, + GetEditableInternalId(s, wrapped)); + } + + // Prints out the map from external to internal state id's (for debugging + // purposes). + void PrintMap() { + for (IdMapIterator map_it = external_to_internal_ids_.begin(); + map_it != NotInEditedMap(); ++map_it) { + LOG(INFO) << "(external,internal)=(" + << map_it->first << "," << map_it->second << ")"; + } + } + + + private: + void SetEmptyAndDeleteKeysForInternalMaps() { + } + + // Returns the iterator of the map from external to internal state id's + // of edits_ for the specified external state id. + IdMapIterator GetEditedIdMapIterator(StateId s) const { + return external_to_internal_ids_.find(s); + } + IdMapIterator NotInEditedMap() const { + return external_to_internal_ids_.end(); + } + + FinalWeightIterator GetFinalWeightIterator(StateId s) const { + return edited_final_weights_.find(s); + } + FinalWeightIterator NotInFinalWeightMap() const { + return edited_final_weights_.end(); + } + + // Returns the internal state id of the specified external id if the state has + // already been made editable, or else copies the state from wrapped_ + // to edits_ and returns the state id of the newly editable state in edits_. + // + // \return makes the specified state editable if it isn't already and returns + // its state id in edits_ + StateId GetEditableInternalId(StateId s, const WrappedFstT *wrapped) { + IdMapIterator id_map_it = GetEditedIdMapIterator(s); + if (id_map_it == NotInEditedMap()) { + StateId new_internal_id = edits_.AddState(); + VLOG(2) << "EditFstData::GetEditableInternalId: editing state " << s + << " of original fst; new internal state id:" << new_internal_id; + external_to_internal_ids_[s] = new_internal_id; + for (ArcIterator< Fst<A> > arc_iterator(*wrapped, s); + !arc_iterator.Done(); + arc_iterator.Next()) { + edits_.AddArc(new_internal_id, arc_iterator.Value()); + } + // copy the final weight + FinalWeightIterator final_weight_it = GetFinalWeightIterator(s); + if (final_weight_it == NotInFinalWeightMap()) { + edits_.SetFinal(new_internal_id, wrapped->Final(s)); + } else { + edits_.SetFinal(new_internal_id, final_weight_it->second); + edited_final_weights_.erase(s); + } + return new_internal_id; + } else { + return id_map_it->second; + } + } + + // A mutable fst (by default, a VectorFst) to contain new states, and/or + // copies of states from a wrapped ExpandedFst that have been modified in + // some way. + MutableFstT edits_; + // A mapping from external state id's to the internal id's of states that + // appear in edits_. + unordered_map<StateId, StateId> external_to_internal_ids_; + // A mapping from external state id's to final state weights assigned to + // those states. The states in this map are *only* those whose final weight + // has been modified; if any other part of the state has been modified, + // the entire state is copied to edits_, and all modifications reside there. + unordered_map<StateId, Weight> edited_final_weights_; + // The number of new states added to this mutable fst impl, which is <= the + // number of states in edits_ (since edits_ contains both edited *and* new + // states). + StateId num_new_states_; + RefCounter ref_count_; +}; + +// EditFstData method implementations: just the Read method. +template <typename A, typename WrappedFstT, typename MutableFstT> +EditFstData<A, WrappedFstT, MutableFstT> * +EditFstData<A, WrappedFstT, MutableFstT>::Read(istream &strm, + const FstReadOptions &opts) { + EditFstData<A, WrappedFstT, MutableFstT> *data = + new EditFstData<A, WrappedFstT, MutableFstT>(); + // next read in MutabelFstT machine that stores edits + FstReadOptions edits_opts(opts); + edits_opts.header = 0; // Contained header was written out, so read it in. + + // Because our internal representation of edited states is a solid object + // of type MutableFstT (defaults to VectorFst<A>) and not a pointer, + // and because the static Read method allocates a new object on the heap, + // we need to call Read, check if there was a failure, use + // MutableFstT::operator= to assign the object (not the pointer) to the + // edits_ data member (which will increase the ref count by 1 on the impl) + // and, finally, delete the heap-allocated object. + MutableFstT *edits = MutableFstT::Read(strm, edits_opts); + if (!edits) { + return 0; + } + data->edits_ = *edits; + delete edits; + // finally, read in rest of private data members + ReadType(strm, &data->external_to_internal_ids_); + ReadType(strm, &data->edited_final_weights_); + ReadType(strm, &data->num_new_states_); + if (!strm) { + LOG(ERROR) << "EditFst::Read: read failed: " << opts.source; + return 0; + } + return data; +} + +// This class enables non-destructive edit operations on a wrapped ExpandedFst. +// The implementation uses copy-on-write semantics at the node level: if a user +// has an underlying fst on which he or she wants to perform a relatively small +// number of edits (read: mutations), then this implementation will copy the +// edited node to an internal MutableFst and perform any edits in situ on that +// copied node. This class supports all the methods of MutableFst except for +// DeleteStates(const vector<StateId> &); thus, new nodes may also be added, and +// one may add transitions from existing nodes of the wrapped fst to new nodes. +// +// template parameters: +// A the type of arc to use +// WrappedFstT the type of fst wrapped by the EditFst instance that +// this EditFstImpl instance is backing +// MutableFstT the type of mutable fst to use internally for edited states; +// crucially, MutableFstT::Copy(false) *must* yield an fst that is +// thread-safe for reading (VectorFst, for example, has this property) +template <typename A, + typename WrappedFstT = ExpandedFst<A>, + typename MutableFstT = VectorFst<A> > +class EditFstImpl : public FstImpl<A> { + public: + using FstImpl<A>::SetProperties; + using FstImpl<A>::SetInputSymbols; + using FstImpl<A>::SetOutputSymbols; + using FstImpl<A>::WriteHeader; + + typedef A Arc; + typedef typename Arc::Weight Weight; + typedef typename Arc::StateId StateId; + + // Constructs an editable fst implementation with no states. Effectively, + // this initially-empty fst will in every way mimic the behavior of + // a VectorFst--more precisely, a VectorFstImpl instance--but with slightly + // slower performance (by a constant factor), due to the fact that + // this class maintains a mapping between external state id's and + // their internal equivalents. + EditFstImpl() { + FstImpl<A>::SetType("edit"); + wrapped_ = new MutableFstT(); + InheritPropertiesFromWrapped(); + data_ = new EditFstData<A, WrappedFstT, MutableFstT>(); + } + + // Wraps the specified ExpandedFst. This constructor requires that the + // specified Fst is an ExpandedFst instance. This requirement is only enforced + // at runtime. (See below for the reason.) + // + // This library uses the pointer-to-implementation or "PIMPL" design pattern. + // In particular, to make it convenient to bind an implementation class to its + // interface, there are a pair of template "binder" classes, one for immutable + // and one for mutable fst's (ImplToFst and ImplToMutableFst, respectively). + // As it happens, the API for the ImplToMutableFst<I,F> class requires that + // the implementation class--the template parameter "I"--have a constructor + // taking a const Fst<A> reference. Accordingly, the constructor here must + // perform a static_cast to the WrappedFstT type required by EditFst and + // therefore EditFstImpl. + explicit EditFstImpl(const Fst<A> &wrapped) + : wrapped_(static_cast<WrappedFstT *>(wrapped.Copy())) { + FstImpl<A>::SetType("edit"); + + data_ = new EditFstData<A, WrappedFstT, MutableFstT>(); + // have edits_ inherit all properties from wrapped_ + data_->SetEditedProperties(wrapped_->Properties(kFstProperties, false), + kFstProperties); + InheritPropertiesFromWrapped(); + } + + // A copy constructor for this implementation class, used to implement + // the Copy() method of the Fst interface. + EditFstImpl(const EditFstImpl &impl) + : FstImpl<A>(), + wrapped_(static_cast<WrappedFstT *>(impl.wrapped_->Copy(true))), + data_(impl.data_) { + data_->IncrRefCount(); + SetProperties(impl.Properties()); + } + + ~EditFstImpl() { + delete wrapped_; + if (!data_->DecrRefCount()) { + delete data_; + } + } + + // const Fst/ExpandedFst operations, declared in the Fst and ExpandedFst + // interfaces + StateId Start() const { + StateId edited_start = data_->EditedStart(); + return edited_start == kNoStateId ? wrapped_->Start() : edited_start; + } + + Weight Final(StateId s) const { + return data_->Final(s, wrapped_); + } + + size_t NumArcs(StateId s) const { + return data_->NumArcs(s, wrapped_); + } + + size_t NumInputEpsilons(StateId s) const { + return data_->NumInputEpsilons(s, wrapped_); + } + + size_t NumOutputEpsilons(StateId s) const { + return data_->NumOutputEpsilons(s, wrapped_); + } + + StateId NumStates() const { + return wrapped_->NumStates() + data_->NumNewStates(); + } + + static EditFstImpl<A, WrappedFstT, MutableFstT> * + Read(istream &strm, + const FstReadOptions &opts); + + bool Write(ostream &strm, const FstWriteOptions &opts) const { + FstHeader hdr; + hdr.SetStart(Start()); + hdr.SetNumStates(NumStates()); + FstWriteOptions header_opts(opts); + header_opts.write_isymbols = false; // Let contained FST hold any symbols. + header_opts.write_osymbols = false; + WriteHeader(strm, header_opts, kFileVersion, &hdr); + + // First, serialize wrapped fst to stream. + FstWriteOptions wrapped_opts(opts); + wrapped_opts.write_header = true; // Force writing contained header. + wrapped_->Write(strm, wrapped_opts); + + data_->Write(strm, opts); + + strm.flush(); + if (!strm) { + LOG(ERROR) << "EditFst::Write: write failed: " << opts.source; + return false; + } + return true; + } + // end const Fst operations + + // non-const MutableFst operations + + // Sets the start state for this fst. + void SetStart(StateId s) { + MutateCheck(); + data_->SetStart(s); + SetProperties(SetStartProperties(FstImpl<A>::Properties())); + } + + // Sets the final state for this fst. + void SetFinal(StateId s, Weight w) { + MutateCheck(); + Weight old_weight = data_->SetFinal(s, w, wrapped_); + SetProperties(SetFinalProperties(FstImpl<A>::Properties(), old_weight, w)); + } + + // Adds a new state to this fst, initially with no arcs. + StateId AddState() { + MutateCheck(); + SetProperties(AddStateProperties(FstImpl<A>::Properties())); + return data_->AddState(NumStates()); + } + + // Adds the specified arc to the specified state of this fst. + void AddArc(StateId s, const Arc &arc) { + MutateCheck(); + const A *prev_arc = data_->AddArc(s, arc, wrapped_); + SetProperties(AddArcProperties(FstImpl<A>::Properties(), s, arc, prev_arc)); + } + + void DeleteStates(const vector<StateId>& dstates) { + FSTERROR() << ": EditFstImpl::DeleteStates(const std::vector<StateId>&): " + << " not implemented"; + SetProperties(kError, kError); + } + + // Deletes all states in this fst. + void DeleteStates(); + + // Removes all but the first n outgoing arcs of the specified state. + void DeleteArcs(StateId s, size_t n) { + MutateCheck(); + data_->DeleteArcs(s, n, wrapped_); + SetProperties(DeleteArcsProperties(FstImpl<A>::Properties())); + } + + // Removes all outgoing arcs from the specified state. + void DeleteArcs(StateId s) { + MutateCheck(); + data_->DeleteArcs(s, wrapped_); + SetProperties(DeleteArcsProperties(FstImpl<A>::Properties())); + } + + void ReserveStates(StateId s) { + } + + void ReserveArcs(StateId s, size_t n) { + } + + // end non-const MutableFst operations + + // Provides information for the generic state iterator. + void InitStateIterator(StateIteratorData<Arc> *data) const { + data->base = 0; + data->nstates = NumStates(); + } + + // Provides information for the generic arc iterator. + void InitArcIterator(StateId s, ArcIteratorData<Arc> *data) const { + data_->InitArcIterator(s, data, wrapped_); + } + + // Provides information for the generic mutable arc iterator. + void InitMutableArcIterator(StateId s, MutableArcIteratorData<A> *data) { + MutateCheck(); + data_->InitMutableArcIterator(s, data, wrapped_); + } + + private: + typedef typename unordered_map<StateId, StateId>::const_iterator + IdMapIterator; + typedef typename unordered_map<StateId, Weight>::const_iterator + FinalWeightIterator; + // Properties always true of this Fst class + static const uint64 kStaticProperties = kExpanded | kMutable; + // Current file format version + static const int kFileVersion = 2; + // Minimum file format version supported + static const int kMinFileVersion = 2; + + // Causes this fst to inherit all the properties from its wrapped fst, except + // for the two properties that always apply to EditFst instances: kExpanded + // and kMutable. + void InheritPropertiesFromWrapped() { + SetProperties(wrapped_->Properties(kCopyProperties, false) | + kStaticProperties); + SetInputSymbols(wrapped_->InputSymbols()); + SetOutputSymbols(wrapped_->OutputSymbols()); + } + + // This method ensures that any operations that alter the mutable data + // portion of this EditFstImpl cause the data_ member to be copied when its + // reference count is greater than 1. Note that this method is distinct from + // MutableFst::Mutate, which gets invoked whenever one of the basic mutation + // methods defined in MutableFst is invoked, such as SetInputSymbols. + // The MutateCheck here in EditFstImpl is invoked whenever one of the + // mutating methods specifically related to the types of edits provided + // by EditFst is performed, such as changing an arc of an existing state + // of the wrapped fst via a MutableArcIterator, or adding a new state via + // AddState(). + void MutateCheck() { + if (data_->RefCount() > 1) { + EditFstData<A, WrappedFstT, MutableFstT> *data_copy = + new EditFstData<A, WrappedFstT, MutableFstT>(*data_); + if (data_ && !data_->DecrRefCount()) { + delete data_; + } + data_ = data_copy; + } + } + + // The fst that this fst wraps. The purpose of this class is to enable + // non-destructive edits on this wrapped fst. + const WrappedFstT *wrapped_; + // The mutable data for this EditFst instance, with delegates for all the + // methods that can mutate data. + EditFstData<A, WrappedFstT, MutableFstT> *data_; +}; + +template <typename A, typename WrappedFstT, typename MutableFstT> +const uint64 EditFstImpl<A, WrappedFstT, MutableFstT>::kStaticProperties; + +// EditFstImpl IMPLEMENTATION STARTS HERE + +template<typename A, typename WrappedFstT, typename MutableFstT> +inline void EditFstImpl<A, WrappedFstT, MutableFstT>::DeleteStates() { + data_->DeleteStates(); + delete wrapped_; + // we are deleting all states, so just forget about pointer to wrapped_ + // and do what default constructor does: set wrapped_ to a new VectorFst + wrapped_ = new MutableFstT(); + uint64 newProps = DeleteAllStatesProperties(FstImpl<A>::Properties(), + kStaticProperties); + FstImpl<A>::SetProperties(newProps); +} + +template <typename A, typename WrappedFstT, typename MutableFstT> +EditFstImpl<A, WrappedFstT, MutableFstT> * +EditFstImpl<A, WrappedFstT, MutableFstT>::Read(istream &strm, + const FstReadOptions &opts) { + EditFstImpl<A, WrappedFstT, MutableFstT> *impl = new EditFstImpl(); + FstHeader hdr; + if (!impl->ReadHeader(strm, opts, kMinFileVersion, &hdr)) { + return 0; + } + impl->SetStart(hdr.Start()); + + // first, read in wrapped fst + FstReadOptions wrapped_opts(opts); + wrapped_opts.header = 0; // Contained header was written out, so read it in. + Fst<A> *wrapped_fst = Fst<A>::Read(strm, wrapped_opts); + if (!wrapped_fst) { + return 0; + } + impl->wrapped_ = static_cast<WrappedFstT *>(wrapped_fst); + + impl->data_ = EditFstData<A, WrappedFstT, MutableFstT>::Read(strm, opts); + + if (!impl->data_) { + delete wrapped_fst; + return 0; + } + + return impl; +} + +// END EditFstImpl IMPLEMENTATION + +// Concrete, editable FST. This class attaches interface to implementation. +template <typename A, + typename WrappedFstT = ExpandedFst<A>, + typename MutableFstT = VectorFst<A> > +class EditFst : + public ImplToMutableFst< EditFstImpl<A, WrappedFstT, MutableFstT> > { + public: + friend class MutableArcIterator< EditFst<A, WrappedFstT, MutableFstT> >; + + typedef A Arc; + typedef typename A::StateId StateId; + typedef EditFstImpl<A, WrappedFstT, MutableFstT> Impl; + + EditFst() : ImplToMutableFst<Impl>(new Impl()) {} + + explicit EditFst(const Fst<A> &fst) : + ImplToMutableFst<Impl>(new Impl(fst)) {} + + explicit EditFst(const WrappedFstT &fst) : + ImplToMutableFst<Impl>(new Impl(fst)) {} + + // See Fst<>::Copy() for doc. + EditFst(const EditFst<A, WrappedFstT, MutableFstT> &fst, bool safe = false) : + ImplToMutableFst<Impl>(fst, safe) {} + + virtual ~EditFst() {} + + // Get a copy of this EditFst. See Fst<>::Copy() for further doc. + virtual EditFst<A, WrappedFstT, MutableFstT> *Copy(bool safe = false) const { + return new EditFst<A, WrappedFstT, MutableFstT>(*this, safe); + } + + EditFst<A, WrappedFstT, MutableFstT> & + operator=(const EditFst<A, WrappedFstT, MutableFstT> &fst) { + SetImpl(fst.GetImpl(), false); + return *this; + } + + virtual EditFst<A, WrappedFstT, MutableFstT> &operator=(const Fst<A> &fst) { + if (this != &fst) { + SetImpl(new Impl(fst)); + } + return *this; + } + + // Read an EditFst from an input stream; return NULL on error. + static EditFst<A, WrappedFstT, MutableFstT> * + Read(istream &strm, + const FstReadOptions &opts) { + Impl* impl = Impl::Read(strm, opts); + return impl ? new EditFst<A>(impl) : 0; + } + + // Read an EditFst from a file; return NULL on error. + // Empty filename reads from standard input. + static EditFst<A, WrappedFstT, MutableFstT> *Read(const string &filename) { + Impl* impl = ImplToExpandedFst<Impl, MutableFst<A> >::Read(filename); + return impl ? new EditFst<A, WrappedFstT, MutableFstT>(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<A>::WriteFile(filename); + } + + virtual void InitStateIterator(StateIteratorData<Arc> *data) const { + GetImpl()->InitStateIterator(data); + } + + virtual void InitArcIterator(StateId s, ArcIteratorData<Arc> *data) const { + GetImpl()->InitArcIterator(s, data); + } + + virtual + void InitMutableArcIterator(StateId s, MutableArcIteratorData<A> *data) { + GetImpl()->InitMutableArcIterator(s, data); + } + private: + explicit EditFst(Impl *impl) : ImplToMutableFst<Impl>(impl) {} + + // Makes visible to friends. + Impl *GetImpl() const { return ImplToFst< Impl, MutableFst<A> >::GetImpl(); } + + void SetImpl(Impl *impl, bool own_impl = true) { + ImplToFst< Impl, MutableFst<A> >::SetImpl(impl, own_impl); + } +}; + +} // namespace fst + +#endif // FST_LIB_EDIT_FST_H_ |