// fstext/epsilon-property.h
  
  // Copyright 2014    Johns Hopkins University (Author: Daniel Povey)
  
  // See ../../COPYING for clarification regarding multiple authors
  //
  // 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
  //
  // THIS CODE IS PROVIDED *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  // KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
  // WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE,
  // MERCHANTABLITY OR NON-INFRINGEMENT.
  // See the Apache 2 License for the specific language governing permissions and
  // limitations under the License.
  
  #ifndef KALDI_FSTEXT_EPSILON_PROPERTY_H_
  #define KALDI_FSTEXT_EPSILON_PROPERTY_H_
  #include <fst/fstlib.h>
  #include <fst/fst-decl.h>
  
  namespace fst {
  
  enum {
    kStateHasEpsilonArcsEntering = 0x1,
    kStateHasNonEpsilonArcsEntering = 0x2,
    kStateHasEpsilonArcsLeaving = 0x4,
    kStateHasNonEpsilonArcsLeaving = 0x8
  }; // use 'char' for this enum.
  
  /// This function will set epsilon_info to have size equal to the
  /// NumStates() of the FST, containing a logical-or of the enum
  /// values kStateHasEpsilonArcsEntering, kStateHasNonEpsilonArcsEntering,
  /// kStateHasEpsilonArcsLeaving, and kStateHasNonEpsilonArcsLeaving.
  /// The meaning should be obvious.  Note: an epsilon arc is defined
  /// as an arc where ilabel == olabel == 0.
  template<class Arc>
  void ComputeStateInfo(const VectorFst<Arc> &fst,
                        std::vector<char> *epsilon_info);
  
  /// This function modifies the fst (while maintaining equivalence) in such a way
  /// that, after the modification, all states of the FST which have epsilon-arcs
  /// entering them, have no non-epsilon arcs entering them, and all states which
  /// have epsilon-arcs leaving them, have no non-epsilon arcs leaving them.  It does
  /// this by creating extra states and adding extra epsilon transitions.  An epsilon
  /// arc is defined as an arc where both the ilabel and the olabel are epsilons.
  /// This function may fail with KALDI_ASSERT for certain cyclic FSTs, but is safe
  /// in the acyclic case.
  template<class Arc>
  void EnsureEpsilonProperty(VectorFst<Arc> *fst);
  
  } // end namespace fst
  
  
  #include "fstext/epsilon-property-inl.h"
  
  #endif