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diff --git a/src/include/fst/arcfilter.h b/src/include/fst/arcfilter.h
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+// 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__