#!/usr/bin/env perl
  # Copyright 2010-2011 Microsoft Corporation
  
  # 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.
  
  # This script removes lines that contain these OOVs on either the
  # third or fourth fields  of the line.  It is intended to remove arcs
  # with OOVs on, from FSTs (probably compiled from ARPAs with OOVs in).
  
  if (  @ARGV < 1 && @ARGV > 2) {
      die "Usage: remove_oovs.pl unk_list.txt [ printed-fst ]
  ";
  }
  
  $unklist = shift @ARGV;
  open(S, "<$unklist") || die "Failed opening unknown-symbol list $unklist
  ";
  while(<S>){ 
      @A = split(" ", $_);
      @A == 1 || die "Bad line in unknown-symbol list: $_";
      $unk{$A[0]} = 1;
  }
  
  $num_removed = 0;
  while(<>){ 
      @A = split(" ", $_);
      if(defined $unk{$A[2]} || defined $unk{$A[3]}) {
          $num_removed++;
      } else {
          print;
      }
  }
  print STDERR "remove_oovs.pl: removed $num_removed lines.
  ";