// See www.openfst.org for extensive documentation on this weighted
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// finite-state transducer library.
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#ifndef FST_EXTENSIONS_SPECIAL_SIGMA_FST_H_
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#define FST_EXTENSIONS_SPECIAL_SIGMA_FST_H_
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#include <memory>
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#include <string>
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#include <fst/const-fst.h>
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#include <fst/matcher-fst.h>
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#include <fst/matcher.h>
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DECLARE_int64(sigma_fst_sigma_label);
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DECLARE_string(sigma_fst_rewrite_mode);
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namespace fst {
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namespace internal {
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template <class Label>
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class SigmaFstMatcherData {
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public:
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explicit SigmaFstMatcherData(Label sigma_label = FLAGS_sigma_fst_sigma_label,
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MatcherRewriteMode rewrite_mode =
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RewriteMode(FLAGS_sigma_fst_rewrite_mode))
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: sigma_label_(sigma_label), rewrite_mode_(rewrite_mode) {}
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SigmaFstMatcherData(const SigmaFstMatcherData &data)
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: sigma_label_(data.sigma_label_), rewrite_mode_(data.rewrite_mode_) {}
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static SigmaFstMatcherData<Label> *Read(std::istream &istrm,
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const FstReadOptions &read) {
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auto *data = new SigmaFstMatcherData<Label>();
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ReadType(istrm, &data->sigma_label_);
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int32 rewrite_mode;
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ReadType(istrm, &rewrite_mode);
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data->rewrite_mode_ = static_cast<MatcherRewriteMode>(rewrite_mode);
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return data;
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}
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bool Write(std::ostream &ostrm, const FstWriteOptions &opts) const {
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WriteType(ostrm, sigma_label_);
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WriteType(ostrm, static_cast<int32>(rewrite_mode_));
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return !ostrm ? false : true;
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}
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Label SigmaLabel() const { return sigma_label_; }
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MatcherRewriteMode RewriteMode() const { return rewrite_mode_; }
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private:
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static MatcherRewriteMode RewriteMode(const string &mode) {
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if (mode == "auto") return MATCHER_REWRITE_AUTO;
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if (mode == "always") return MATCHER_REWRITE_ALWAYS;
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if (mode == "never") return MATCHER_REWRITE_NEVER;
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LOG(WARNING) << "SigmaFst: Unknown rewrite mode: " << mode << ". "
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<< "Defaulting to auto.";
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return MATCHER_REWRITE_AUTO;
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}
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Label sigma_label_;
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MatcherRewriteMode rewrite_mode_;
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};
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} // namespace internal
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constexpr uint8 kSigmaFstMatchInput = 0x01; // Input matcher is SigmaMatcher.
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constexpr uint8 kSigmaFstMatchOutput = 0x02; // Output matcher is SigmaMatcher.
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template <class M, uint8 flags = kSigmaFstMatchInput | kSigmaFstMatchOutput>
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class SigmaFstMatcher : public SigmaMatcher<M> {
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public:
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using FST = typename M::FST;
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using Arc = typename M::Arc;
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using StateId = typename Arc::StateId;
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using Label = typename Arc::Label;
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using Weight = typename Arc::Weight;
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using MatcherData = internal::SigmaFstMatcherData<Label>;
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enum : uint8 { kFlags = flags };
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// This makes a copy of the FST.
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SigmaFstMatcher(
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const FST &fst, MatchType match_type,
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std::shared_ptr<MatcherData> data = std::make_shared<MatcherData>())
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: SigmaMatcher<M>(
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fst, match_type,
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SigmaLabel(match_type,
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data ? data->SigmaLabel() : MatcherData().SigmaLabel()),
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data ? data->RewriteMode() : MatcherData().RewriteMode()),
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data_(data) {}
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// This doesn't copy the FST.
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SigmaFstMatcher(
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const FST *fst, MatchType match_type,
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std::shared_ptr<MatcherData> data = std::make_shared<MatcherData>())
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: SigmaMatcher<M>(
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fst, match_type,
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SigmaLabel(match_type,
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data ? data->SigmaLabel() : MatcherData().SigmaLabel()),
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data ? data->RewriteMode() : MatcherData().RewriteMode()),
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data_(data) {}
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// This makes a copy of the FST.
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SigmaFstMatcher(const SigmaFstMatcher<M, flags> &matcher, bool safe = false)
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: SigmaMatcher<M>(matcher, safe), data_(matcher.data_) {}
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SigmaFstMatcher<M, flags> *Copy(bool safe = false) const override {
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return new SigmaFstMatcher<M, flags>(*this, safe);
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}
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const MatcherData *GetData() const { return data_.get(); }
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std::shared_ptr<MatcherData> GetSharedData() const { return data_; }
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private:
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static Label SigmaLabel(MatchType match_type, Label label) {
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if (match_type == MATCH_INPUT && flags & kSigmaFstMatchInput) return label;
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if (match_type == MATCH_OUTPUT && flags & kSigmaFstMatchOutput)
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return label;
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return kNoLabel;
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}
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std::shared_ptr<MatcherData> data_;
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};
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extern const char sigma_fst_type[];
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extern const char input_sigma_fst_type[];
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extern const char output_sigma_fst_type[];
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using StdSigmaFst = MatcherFst<ConstFst<StdArc>,
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SigmaFstMatcher<SortedMatcher<ConstFst<StdArc>>>,
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sigma_fst_type>;
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using LogSigmaFst = MatcherFst<ConstFst<LogArc>,
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SigmaFstMatcher<SortedMatcher<ConstFst<LogArc>>>,
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sigma_fst_type>;
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using Log64SigmaFst =
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MatcherFst<ConstFst<Log64Arc>,
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SigmaFstMatcher<SortedMatcher<ConstFst<Log64Arc>>>,
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input_sigma_fst_type>;
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using StdInputSigmaFst = MatcherFst<
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ConstFst<StdArc>,
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SigmaFstMatcher<SortedMatcher<ConstFst<StdArc>>, kSigmaFstMatchInput>,
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input_sigma_fst_type>;
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using LogInputSigmaFst = MatcherFst<
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ConstFst<LogArc>,
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SigmaFstMatcher<SortedMatcher<ConstFst<LogArc>>, kSigmaFstMatchInput>,
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input_sigma_fst_type>;
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using Log64InputSigmaFst = MatcherFst<
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ConstFst<Log64Arc>,
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SigmaFstMatcher<SortedMatcher<ConstFst<Log64Arc>>, kSigmaFstMatchInput>,
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input_sigma_fst_type>;
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using StdOutputSigmaFst = MatcherFst<
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ConstFst<StdArc>,
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SigmaFstMatcher<SortedMatcher<ConstFst<StdArc>>, kSigmaFstMatchOutput>,
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output_sigma_fst_type>;
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using LogOutputSigmaFst = MatcherFst<
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ConstFst<LogArc>,
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SigmaFstMatcher<SortedMatcher<ConstFst<LogArc>>, kSigmaFstMatchOutput>,
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output_sigma_fst_type>;
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using Log64OutputSigmaFst = MatcherFst<
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ConstFst<Log64Arc>,
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SigmaFstMatcher<SortedMatcher<ConstFst<Log64Arc>>, kSigmaFstMatchOutput>,
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output_sigma_fst_type>;
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} // namespace fst
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#endif // FST_EXTENSIONS_SPECIAL_SIGMA_FST_H_
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