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+
+// 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: jpr@google.com (Jake Ratkiewicz)
+
+#ifndef FST_SCRIPT_FST_CLASS_H_
+#define FST_SCRIPT_FST_CLASS_H_
+
+#include <string>
+
+#include <fst/fst.h>
+#include <fst/mutable-fst.h>
+#include <fst/vector-fst.h>
+#include <iostream>
+#include <fstream>
+
+// Classes to support "boxing" all existing types of FST arcs in a single
+// FstClass which hides the arc types. This allows clients to load
+// and work with FSTs without knowing the arc type.
+
+// These classes are only recommended for use in high-level scripting
+// applications. Most users should use the lower-level templated versions
+// corresponding to these classes.
+
+namespace fst {
+namespace script {
+
+//
+// Abstract base class defining the set of functionalities implemented
+// in all impls, and passed through by all bases Below FstClassBase
+// the class hierarchy bifurcates; FstClassImplBase serves as the base
+// class for all implementations (of which FstClassImpl is currently
+// the only one) and FstClass serves as the base class for all
+// interfaces.
+//
+class FstClassBase {
+ public:
+ virtual const string &ArcType() const = 0;
+ virtual const string &FstType() const = 0;
+ virtual const string &WeightType() const = 0;
+ virtual const SymbolTable *InputSymbols() const = 0;
+ virtual const SymbolTable *OutputSymbols() const = 0;
+ virtual void Write(const string& fname) const = 0;
+ virtual uint64 Properties(uint64 mask, bool test) const = 0;
+ virtual ~FstClassBase() { }
+};
+
+class FstClassImplBase : public FstClassBase {
+ public:
+ virtual FstClassImplBase *Copy() = 0;
+ virtual void SetInputSymbols(SymbolTable *is) = 0;
+ virtual void SetOutputSymbols(SymbolTable *is) = 0;
+ virtual ~FstClassImplBase() { }
+};
+
+
+//
+// CONTAINER CLASS
+// Wraps an Fst<Arc>, hiding its arc type. Whether this Fst<Arc>
+// pointer refers to a special kind of FST (e.g. a MutableFst) is
+// known by the type of interface class that owns the pointer to this
+// container.
+//
+
+template<class Arc>
+class FstClassImpl : public FstClassImplBase {
+ public:
+ explicit FstClassImpl(Fst<Arc> *impl,
+ bool should_own = false) :
+ impl_(should_own ? impl : impl->Copy()) { }
+
+ virtual const string &ArcType() const {
+ return Arc::Type();
+ }
+
+ virtual const string &FstType() const {
+ return impl_->Type();
+ }
+
+ virtual const string &WeightType() const {
+ return Arc::Weight::Type();
+ }
+
+ virtual const SymbolTable *InputSymbols() const {
+ return impl_->InputSymbols();
+ }
+
+ virtual const SymbolTable *OutputSymbols() const {
+ return impl_->OutputSymbols();
+ }
+
+ // Warning: calling this method casts the FST to a mutable FST.
+ virtual void SetInputSymbols(SymbolTable *is) {
+ static_cast<MutableFst<Arc> *>(impl_)->SetInputSymbols(is);
+ }
+
+ // Warning: calling this method casts the FST to a mutable FST.
+ virtual void SetOutputSymbols(SymbolTable *os) {
+ static_cast<MutableFst<Arc> *>(impl_)->SetOutputSymbols(os);
+ }
+
+ virtual void Write(const string &fname) const {
+ impl_->Write(fname);
+ }
+
+ virtual uint64 Properties(uint64 mask, bool test) const {
+ return impl_->Properties(mask, test);
+ }
+
+ virtual ~FstClassImpl() { delete impl_; }
+
+ Fst<Arc> *GetImpl() { return impl_; }
+
+ virtual FstClassImpl *Copy() {
+ return new FstClassImpl<Arc>(impl_);
+ }
+
+ private:
+ Fst<Arc> *impl_;
+};
+
+//
+// BASE CLASS DEFINITIONS
+//
+
+class MutableFstClass;
+
+class FstClass : public FstClassBase {
+ public:
+ template<class Arc>
+ static FstClass *Read(istream &stream,
+ const FstReadOptions &opts) {
+ if (!opts.header) {
+ FSTERROR() << "FstClass::Read: options header not specified";
+ return 0;
+ }
+ const FstHeader &hdr = *opts.header;
+
+ if (hdr.Properties() & kMutable) {
+ return ReadTypedFst<MutableFstClass, MutableFst<Arc> >(stream, opts);
+ } else {
+ return ReadTypedFst<FstClass, Fst<Arc> >(stream, opts);
+ }
+ }
+
+ template<class Arc>
+ explicit FstClass(Fst<Arc> *fst) : impl_(new FstClassImpl<Arc>(fst)) { }
+
+ explicit FstClass(const FstClass &other) : impl_(other.impl_->Copy()) { }
+
+ static FstClass *Read(const string &fname);
+
+ virtual const string &ArcType() const {
+ return impl_->ArcType();
+ }
+
+ virtual const string& FstType() const {
+ return impl_->FstType();
+ }
+
+ virtual const SymbolTable *InputSymbols() const {
+ return impl_->InputSymbols();
+ }
+
+ virtual const SymbolTable *OutputSymbols() const {
+ return impl_->OutputSymbols();
+ }
+
+ virtual const string& WeightType() const {
+ return impl_->WeightType();
+ }
+
+ virtual void Write(const string &fname) const {
+ impl_->Write(fname);
+ }
+
+ virtual uint64 Properties(uint64 mask, bool test) const {
+ return impl_->Properties(mask, test);
+ }
+
+ template<class Arc>
+ const Fst<Arc> *GetFst() const {
+ if (Arc::Type() != ArcType()) {
+ return NULL;
+ } else {
+ FstClassImpl<Arc> *typed_impl = static_cast<FstClassImpl<Arc> *>(impl_);
+ return typed_impl->GetImpl();
+ }
+ }
+
+ virtual ~FstClass() { delete impl_; }
+
+ // These methods are required by IO registration
+ template<class Arc>
+ static FstClassImplBase *Convert(const FstClass &other) {
+ LOG(ERROR) << "Doesn't make sense to convert any class to type FstClass.";
+ return 0;
+ }
+
+ template<class Arc>
+ static FstClassImplBase *Create() {
+ LOG(ERROR) << "Doesn't make sense to create an FstClass with a "
+ << "particular arc type.";
+ return 0;
+ }
+ protected:
+ explicit FstClass(FstClassImplBase *impl) : impl_(impl) { }
+
+ // Generic template method for reading an arc-templated FST of type
+ // UnderlyingT, and returning it wrapped as FstClassT, with appropriate
+ // error checking. Called from arc-templated Read() static methods.
+ template<class FstClassT, class UnderlyingT>
+ static FstClassT* ReadTypedFst(istream &stream,
+ const FstReadOptions &opts) {
+ UnderlyingT *u = UnderlyingT::Read(stream, opts);
+ if (!u) {
+ return 0;
+ } else {
+ FstClassT *r = new FstClassT(u);
+ delete u;
+ return r;
+ }
+ }
+
+ FstClassImplBase *GetImpl() { return impl_; }
+ private:
+ FstClassImplBase *impl_;
+};
+
+//
+// Specific types of FstClass with special properties
+//
+
+class MutableFstClass : public FstClass {
+ public:
+ template<class Arc>
+ explicit MutableFstClass(MutableFst<Arc> *fst) :
+ FstClass(fst) { }
+
+ template<class Arc>
+ MutableFst<Arc> *GetMutableFst() {
+ Fst<Arc> *fst = const_cast<Fst<Arc> *>(this->GetFst<Arc>());
+ MutableFst<Arc> *mfst = static_cast<MutableFst<Arc> *>(fst);
+
+ return mfst;
+ }
+
+ template<class Arc>
+ static MutableFstClass *Read(istream &stream,
+ const FstReadOptions &opts) {
+ MutableFst<Arc> *mfst = MutableFst<Arc>::Read(stream, opts);
+ if (!mfst) {
+ return 0;
+ } else {
+ MutableFstClass *retval = new MutableFstClass(mfst);
+ delete mfst;
+ return retval;
+ }
+ }
+
+ static MutableFstClass *Read(const string &fname, bool convert = false);
+
+ virtual void SetInputSymbols(SymbolTable *is) {
+ GetImpl()->SetInputSymbols(is);
+ }
+
+ virtual void SetOutputSymbols(SymbolTable *os) {
+ GetImpl()->SetOutputSymbols(os);
+ }
+
+ // These methods are required by IO registration
+ template<class Arc>
+ static FstClassImplBase *Convert(const FstClass &other) {
+ LOG(ERROR) << "Doesn't make sense to convert any class to type "
+ << "MutableFstClass.";
+ return 0;
+ }
+
+ template<class Arc>
+ static FstClassImplBase *Create() {
+ LOG(ERROR) << "Doesn't make sense to create a MutableFstClass with a "
+ << "particular arc type.";
+ return 0;
+ }
+
+ protected:
+ explicit MutableFstClass(FstClassImplBase *impl) : FstClass(impl) { }
+};
+
+
+class VectorFstClass : public MutableFstClass {
+ public:
+ explicit VectorFstClass(const FstClass &other);
+ explicit VectorFstClass(const string &arc_type);
+
+ template<class Arc>
+ explicit VectorFstClass(VectorFst<Arc> *fst) :
+ MutableFstClass(fst) { }
+
+ template<class Arc>
+ static VectorFstClass *Read(istream &stream,
+ const FstReadOptions &opts) {
+ VectorFst<Arc> *vfst = VectorFst<Arc>::Read(stream, opts);
+ if (!vfst) {
+ return 0;
+ } else {
+ VectorFstClass *retval = new VectorFstClass(vfst);
+ delete vfst;
+ return retval;
+ }
+ }
+
+ static VectorFstClass *Read(const string &fname);
+
+ // Converter / creator for known arc types
+ template<class Arc>
+ static FstClassImplBase *Convert(const FstClass &other) {
+ return new FstClassImpl<Arc>(new VectorFst<Arc>(
+ *other.GetFst<Arc>()), true);
+ }
+
+ template<class Arc>
+ static FstClassImplBase *Create() {
+ return new FstClassImpl<Arc>(new VectorFst<Arc>(), true);
+ }
+};
+
+} // namespace script
+} // namespace fst
+
+
+#endif // FST_SCRIPT_FST_CLASS_H_
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