1// fstshortestpath.cc
2
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14//
15// Copyright 2005-2010 Google, Inc.
16// Author: allauzen@google.com (Cyril Allauzen)
17// Modified: jpr@google.com (Jake Ratkiewicz) to use FstClass
18//
19// \file
20// Find shortest path(s) in an FST.
21
22#include <fst/script/shortest-path.h>
23
24DEFINE_double(delta, fst::kDelta, "Comparison/quantization delta");
25DEFINE_int64(nshortest, 1, "Return N-shortest paths");
26DEFINE_bool(unique, false, "Return unique strings");
27DEFINE_string(weight, "", "Weight threshold");
28DEFINE_int64(nstate, fst::kNoStateId, "State number threshold");
29DEFINE_string(queue_type, "auto", "Queue type: one of \"auto\", "
30              "\"fifo\", \"lifo\", \"shortest\', \"state\", \"top\"");
31
32int main(int argc, char **argv) {
33  namespace s = fst::script;
34  using fst::script::FstClass;
35  using fst::script::MutableFstClass;
36  using fst::script::VectorFstClass;
37  using fst::script::WeightClass;
38
39  string usage = "Finds shortest path(s) in an FST.\n\n  Usage: ";
40  usage += argv[0];
41  usage += " [in.fst [out.fst]]\n";
42
43
44  std::set_new_handler(FailedNewHandler);
45  SET_FLAGS(usage.c_str(), &argc, &argv, true);
46  if (argc > 3) {
47    ShowUsage();
48    return 1;
49  }
50
51  string in_fname = (argc > 1 && (strcmp(argv[1], "-") != 0)) ? argv[1] : "";
52  string out_fname = argc > 2 ? argv[2] : "";
53
54  FstClass *ifst = FstClass::Read(in_fname);
55  if (!ifst) return 1;
56
57  WeightClass weight_threshold = FLAGS_weight.empty() ?
58      WeightClass::Zero() :
59      WeightClass(ifst->WeightType(), FLAGS_weight);
60
61  VectorFstClass ofst(ifst->ArcType());
62  vector<WeightClass> distance;
63
64  fst::QueueType qt;
65
66  if (FLAGS_queue_type == "auto") {
67    qt = fst::AUTO_QUEUE;
68  } else if (FLAGS_queue_type == "fifo") {
69    qt = fst::FIFO_QUEUE;
70  } else if (FLAGS_queue_type == "lifo") {
71    qt = fst::LIFO_QUEUE;
72  } else if (FLAGS_queue_type == "shortest") {
73    qt = fst::SHORTEST_FIRST_QUEUE;
74  } else if (FLAGS_queue_type == "state") {
75    qt = fst::STATE_ORDER_QUEUE;
76  } else if (FLAGS_queue_type == "top") {
77    qt = fst::TOP_ORDER_QUEUE;
78  } else {
79    LOG(ERROR) << "Unknown or unsupported queue type: " << FLAGS_queue_type;
80    return 1;
81  }
82
83  s::ShortestPathOptions opts(
84      qt, FLAGS_nshortest, FLAGS_unique, false, FLAGS_delta,
85      false, weight_threshold, FLAGS_nstate);
86
87  s::ShortestPath(*ifst, &ofst, &distance, opts);
88
89  ofst.Write(out_fname);
90
91  return 0;
92}
93