| // arcfilter.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: riley@google.com (Michael Riley) |
| // |
| // \file |
| // Function objects to restrict which arcs are traversed in an FST. |
| |
| #ifndef FST_LIB_ARCFILTER_H__ |
| #define FST_LIB_ARCFILTER_H__ |
| |
| |
| #include <fst/fst.h> |
| #include <fst/util.h> |
| |
| |
| namespace fst { |
| |
| // True for all arcs. |
| template <class A> |
| class AnyArcFilter { |
| public: |
| bool operator()(const A &arc) const { return true; } |
| }; |
| |
| |
| // True for (input/output) epsilon arcs. |
| template <class A> |
| class EpsilonArcFilter { |
| public: |
| bool operator()(const A &arc) const { |
| return arc.ilabel == 0 && arc.olabel == 0; |
| } |
| }; |
| |
| |
| // True for input epsilon arcs. |
| template <class A> |
| class InputEpsilonArcFilter { |
| public: |
| bool operator()(const A &arc) const { |
| return arc.ilabel == 0; |
| } |
| }; |
| |
| |
| // True for output epsilon arcs. |
| template <class A> |
| class OutputEpsilonArcFilter { |
| public: |
| bool operator()(const A &arc) const { |
| return arc.olabel == 0; |
| } |
| }; |
| |
| |
| // True if specified labels match (don't match) when keep_match is |
| // true (false). |
| template <class A> |
| class MultiLabelArcFilter { |
| public: |
| typedef typename A::Label Label; |
| |
| MultiLabelArcFilter(bool match_input = true, bool keep_match = true) |
| : match_input_(match_input), |
| keep_match_(keep_match) {} |
| |
| |
| bool operator()(const A &arc) const { |
| Label label = match_input_ ? arc.ilabel : arc.olabel; |
| bool match = labels_.Find(label) != labels_.End(); |
| return keep_match_ ? match : !match; |
| } |
| |
| void AddLabel(Label label) { |
| labels_.Insert(label); |
| } |
| |
| private: |
| CompactSet<Label, kNoLabel> labels_; |
| bool match_input_; |
| bool keep_match_; |
| }; |
| |
| } // namespace fst |
| |
| #endif // FST_LIB_ARCFILTER_H__ |