// See www.openfst.org for extensive documentation on this weighted
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// finite-state transducer library.
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//
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// Subtracts an unweighted DFA from an FSA.
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#include <cstring>
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#include <memory>
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#include <string>
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#include <fst/flags.h>
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#include <fst/log.h>
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#include <fst/script/difference.h>
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#include <fst/script/getters.h>
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DECLARE_string(compose_filter);
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DECLARE_bool(connect);
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int fstdifference_main(int argc, char **argv) {
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namespace s = fst::script;
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using fst::ComposeFilter;
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using fst::DifferenceOptions;
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using fst::script::FstClass;
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using fst::script::VectorFstClass;
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string usage = "Subtracts an unweighted DFA from an FSA.\n\n Usage: ";
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usage += argv[0];
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usage += " in1.fst in2.fst [out.fst]\n";
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std::set_new_handler(FailedNewHandler);
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SET_FLAGS(usage.c_str(), &argc, &argv, true);
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if (argc < 3 || argc > 4) {
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ShowUsage();
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return 1;
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}
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const string in1_name = strcmp(argv[1], "-") == 0 ? "" : argv[1];
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const string in2_name = strcmp(argv[2], "-") == 0 ? "" : argv[2];
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const string out_name = argc > 3 ? argv[3] : "";
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if (in1_name.empty() && in2_name.empty()) {
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LOG(ERROR) << argv[0] << ": Can't take both inputs from standard input";
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return 1;
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}
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std::unique_ptr<FstClass> ifst1(FstClass::Read(in1_name));
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if (!ifst1) return 1;
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std::unique_ptr<FstClass> ifst2(FstClass::Read(in2_name));
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if (!ifst2) return 1;
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VectorFstClass ofst(ifst1->ArcType());
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ComposeFilter compose_filter;
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if (!s::GetComposeFilter(FLAGS_compose_filter, &compose_filter)) {
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LOG(ERROR) << argv[0] << ": Unknown or unsupported compose filter type: "
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<< FLAGS_compose_filter;
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return 1;
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}
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const DifferenceOptions opts(FLAGS_connect, compose_filter);
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s::Difference(*ifst1, *ifst2, &ofst, opts);
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return !ofst.Write(out_name);
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}
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