1 // mutable-fst.h 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 // 15 // 16 // \file 17 // Expanded FST augmented with mutators - interface class definition 18 // and mutable arc iterator interface. 19 20 #ifndef FST_LIB_MUTABLE_FST_H__ 21 #define FST_LIB_MUTABLE_FST_H__ 22 23 #include <vector> 24 25 #include "fst/lib/expanded-fst.h" 26 27 namespace fst { 28 29 template <class A> class MutableArcIteratorData; 30 31 // An expanded FST plus mutators (use MutableArcIterator to modify arcs). 32 template <class A> 33 class MutableFst : public ExpandedFst<A> { 34 public: 35 typedef A Arc; 36 typedef typename A::Weight Weight; 37 typedef typename A::StateId StateId; 38 39 virtual MutableFst<A> &operator=(const Fst<A> &fst) = 0; 40 41 virtual void SetStart(StateId) = 0; // Set the initial state 42 virtual void SetFinal(StateId, Weight) = 0; // Set a state's final weight 43 virtual void SetProperties(uint64 props, 44 uint64 mask) = 0; // Set property bits wrt mask 45 virtual StateId AddState() = 0; // Add a state, return its ID 46 virtual void AddArc(StateId, const A &arc) = 0; // Add an arc to state 47 48 virtual void DeleteStates(const vector<StateId>&) = 0; // Delete some states 49 virtual void DeleteStates() = 0; // Delete all states 50 virtual void DeleteArcs(StateId, size_t n) = 0; // Delete some arcs at state 51 virtual void DeleteArcs(StateId) = 0; // Delete all arcs at state 52 53 // Return input label symbol table; return NULL if not specified 54 virtual const SymbolTable* InputSymbols() const = 0; 55 // Return output label symbol table; return NULL if not specified 56 virtual const SymbolTable* OutputSymbols() const = 0; 57 58 // Return input label symbol table; return NULL if not specified 59 virtual SymbolTable* InputSymbols() = 0; 60 // Return output label symbol table; return NULL if not specified 61 virtual SymbolTable* OutputSymbols() = 0; 62 63 // Set input label symbol table; NULL signifies not unspecified 64 virtual void SetInputSymbols(const SymbolTable* isyms) = 0; 65 // Set output label symbol table; NULL signifies not unspecified 66 virtual void SetOutputSymbols(const SymbolTable* osyms) = 0; 67 68 // Get a copy of this MutableFst. 69 virtual MutableFst<A> *Copy() const = 0; 70 // Read an MutableFst from an input stream; return NULL on error. 71 static MutableFst<A> *Read(istream &strm, const FstReadOptions &opts) { 72 FstReadOptions ropts(opts); 73 FstHeader hdr; 74 if (ropts.header) 75 hdr = *opts.header; 76 else { 77 if (!hdr.Read(strm, opts.source)) 78 return 0; 79 ropts.header = &hdr; 80 } 81 if (!(hdr.Properties() & kMutable)) { 82 LOG(ERROR) << "MutableFst::Read: Not an MutableFst: " << ropts.source; 83 return 0; 84 } 85 FstRegister<A> *registr = FstRegister<A>::GetRegister(); 86 const typename FstRegister<A>::Reader reader = 87 registr->GetReader(hdr.FstType()); 88 if (!reader) { 89 LOG(ERROR) << "MutableFst::Read: Unknown FST type \"" << hdr.FstType() 90 << "\" (arc type = \"" << A::Type() 91 << "\"): " << ropts.source; 92 return 0; 93 } 94 Fst<A> *fst = reader(strm, ropts); 95 if (!fst) return 0; 96 return down_cast<MutableFst<A> *>(fst); 97 } 98 // Read an MutableFst from a file; returns NULL on error. 99 static MutableFst<A> *Read(const string &filename) { 100 ifstream strm(filename.c_str()); 101 if (!strm) { 102 LOG(ERROR) << "MutableFst::Read: Can't open file: " << filename; 103 return 0; 104 } 105 return Read(strm, FstReadOptions(filename)); 106 } 107 108 // For generic mutuble arc iterator construction; not normally called 109 // directly by users. 110 virtual void InitMutableArcIterator(StateId s, 111 MutableArcIteratorData<A> *) = 0; 112 }; 113 114 // Mutable arc iterator interface, templated on the Arc definition. 115 template <class A> 116 class MutableArcIteratorBase : public ArcIteratorBase<A> { 117 public: 118 typedef A Arc; 119 virtual void SetValue(const A &arc) = 0; // Set current arc's contents 120 }; 121 122 template <class A> 123 struct MutableArcIteratorData { 124 MutableArcIteratorBase<A> *base; // Specific iterator 125 }; 126 127 // Generic mutable arc iterator, templated on the FST definition 128 // - a wrapper around pointer to specific one. 129 // Here is a typical use: \code 130 // for (MutableArcIterator<StdFst> aiter(&fst, s)); 131 // !aiter.Done(); 132 // aiter.Next()) { 133 // StdArc arc = aiter.Value(); 134 // arc.ilabel = 7; 135 // aiter.SetValue(arc); 136 // ... 137 // } \endcode 138 // This version requires function calls. 139 template <class F> 140 class MutableArcIterator : public MutableArcIteratorBase<typename F::Arc> { 141 public: 142 typedef typename F::Arc Arc; 143 typedef typename Arc::StateId StateId; 144 145 MutableArcIterator(F *fst, StateId s) { 146 fst->InitMutableArcIterator(s, &data_); 147 } 148 ~MutableArcIterator() { delete data_.base; } 149 150 bool Done() const { return data_.base->Done(); } 151 const Arc& Value() const { return data_.base->Value(); } 152 void Next() { data_.base->Next(); } 153 void Reset() { data_.base->Reset(); } 154 void Seek(size_t a) { data_.base->Seek(a); } 155 void SetValue(const Arc &a) { data_.base->SetValue(a); } 156 157 private: 158 MutableArcIteratorData<Arc> data_; 159 DISALLOW_EVIL_CONSTRUCTORS(MutableArcIterator); 160 }; 161 162 // A useful alias when using StdArc. 163 typedef MutableFst<StdArc> StdMutableFst; 164 165 } // namespace fst; 166 167 #endif // FST_LIB_MUTABLE_FST_H__ 168
