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author | Determinant <[email protected]> | 2015-08-14 11:51:42 +0800 |
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committer | Determinant <[email protected]> | 2015-08-14 11:51:42 +0800 |
commit | 96a32415ab43377cf1575bd3f4f2980f58028209 (patch) | |
tree | 30a2d92d73e8f40ac87b79f6f56e227bfc4eea6e /kaldi_io/src/tools/openfst/include/fst/invert.h | |
parent | c177a7549bd90670af4b29fa813ddea32cfe0f78 (diff) |
add implementation for kaldi io (by ymz)
Diffstat (limited to 'kaldi_io/src/tools/openfst/include/fst/invert.h')
-rw-r--r-- | kaldi_io/src/tools/openfst/include/fst/invert.h | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/kaldi_io/src/tools/openfst/include/fst/invert.h b/kaldi_io/src/tools/openfst/include/fst/invert.h new file mode 100644 index 0000000..bc83a5d --- /dev/null +++ b/kaldi_io/src/tools/openfst/include/fst/invert.h @@ -0,0 +1,125 @@ +// invert.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: [email protected] (Michael Riley) +// +// \file +// Functions and classes to invert an Fst. + +#ifndef FST_LIB_INVERT_H__ +#define FST_LIB_INVERT_H__ + +#include <fst/arc-map.h> +#include <fst/mutable-fst.h> + + +namespace fst { + +// Mapper to implement inversion of an arc. +template <class A> struct InvertMapper { + InvertMapper() {} + + A operator()(const A &arc) { + return A(arc.olabel, arc.ilabel, arc.weight, arc.nextstate); + } + + MapFinalAction FinalAction() const { return MAP_NO_SUPERFINAL; } + + MapSymbolsAction InputSymbolsAction() const { return MAP_CLEAR_SYMBOLS; } + + MapSymbolsAction OutputSymbolsAction() const { return MAP_CLEAR_SYMBOLS;} + + uint64 Properties(uint64 props) { return InvertProperties(props); } +}; + + +// Inverts the transduction corresponding to an FST by exchanging the +// FST's input and output labels. This version modifies its input. +// +// Complexity: +// - Time: O(V + E) +// - Space: O(1) +// where V = # of states and E = # of arcs. +template<class Arc> inline +void Invert(MutableFst<Arc> *fst) { + SymbolTable *input = fst->InputSymbols() ? fst->InputSymbols()->Copy() : 0; + SymbolTable *output = fst->OutputSymbols() ? fst->OutputSymbols()->Copy() : 0; + ArcMap(fst, InvertMapper<Arc>()); + fst->SetInputSymbols(output); + fst->SetOutputSymbols(input); + delete input; + delete output; +} + + +// Inverts the transduction corresponding to an FST by exchanging the +// FST's input and output labels. This version is a delayed Fst. +// +// Complexity: +// - Time: O(v + e) +// - Space: O(1) +// where v = # of states visited, e = # of arcs visited. Constant +// time and to visit an input state or arc is assumed and exclusive +// of caching. +template <class A> +class InvertFst : public ArcMapFst<A, A, InvertMapper<A> > { + public: + typedef A Arc; + typedef InvertMapper<A> C; + typedef ArcMapFstImpl< A, A, InvertMapper<A> > Impl; + using ImplToFst<Impl>::GetImpl; + + explicit InvertFst(const Fst<A> &fst) : ArcMapFst<A, A, C>(fst, C()) { + GetImpl()->SetOutputSymbols(fst.InputSymbols()); + GetImpl()->SetInputSymbols(fst.OutputSymbols()); + } + + // See Fst<>::Copy() for doc. + InvertFst(const InvertFst<A> &fst, bool safe = false) + : ArcMapFst<A, A, C>(fst, safe) {} + + // Get a copy of this InvertFst. See Fst<>::Copy() for further doc. + virtual InvertFst<A> *Copy(bool safe = false) const { + return new InvertFst(*this, safe); + } +}; + + +// Specialization for InvertFst. +template <class A> +class StateIterator< InvertFst<A> > + : public StateIterator< ArcMapFst<A, A, InvertMapper<A> > > { + public: + explicit StateIterator(const InvertFst<A> &fst) + : StateIterator< ArcMapFst<A, A, InvertMapper<A> > >(fst) {} +}; + + +// Specialization for InvertFst. +template <class A> +class ArcIterator< InvertFst<A> > + : public ArcIterator< ArcMapFst<A, A, InvertMapper<A> > > { + public: + ArcIterator(const InvertFst<A> &fst, typename A::StateId s) + : ArcIterator< ArcMapFst<A, A, InvertMapper<A> > >(fst, s) {} +}; + + +// Useful alias when using StdArc. +typedef InvertFst<StdArc> StdInvertFst; + +} // namespace fst + +#endif // FST_LIB_INVERT_H__ |