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// 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: jpr@google.com (Jake Ratkiewicz)
#ifndef FST_SCRIPT_SHORTEST_DISTANCE_H_
#define FST_SCRIPT_SHORTEST_DISTANCE_H_
#include <vector>
using std::vector;
#include <fst/script/arg-packs.h>
#include <fst/script/fst-class.h>
#include <fst/script/weight-class.h>
#include <fst/script/prune.h> // for ArcFilterType
#include <fst/queue.h> // for QueueType
#include <fst/shortest-distance.h>
namespace fst {
namespace script {
enum ArcFilterType { ANY_ARC_FILTER, EPSILON_ARC_FILTER,
INPUT_EPSILON_ARC_FILTER, OUTPUT_EPSILON_ARC_FILTER };
// See nlp/fst/lib/shortest-distance.h for the template options class
// that this one shadows
struct ShortestDistanceOptions {
const QueueType queue_type;
const ArcFilterType arc_filter_type;
const int64 source;
const float delta;
const bool first_path;
ShortestDistanceOptions(QueueType qt, ArcFilterType aft, int64 s,
float d)
: queue_type(qt), arc_filter_type(aft), source(s), delta(d),
first_path(false) { }
};
// 1
typedef args::Package<const FstClass &, vector<WeightClass> *,
const ShortestDistanceOptions &> ShortestDistanceArgs1;
template<class Queue, class Arc, class ArcFilter>
struct QueueConstructor {
// template<class Arc, class ArcFilter>
static Queue *Construct(const Fst<Arc> &,
const vector<typename Arc::Weight> *) {
return new Queue();
}
};
// Specializations to deal with AutoQueue, NaturalShortestFirstQueue,
// and TopOrderQueue's different constructors
template<class Arc, class ArcFilter>
struct QueueConstructor<AutoQueue<typename Arc::StateId>, Arc, ArcFilter> {
// template<class Arc, class ArcFilter>
static AutoQueue<typename Arc::StateId> *Construct(
const Fst<Arc> &fst,
const vector<typename Arc::Weight> *distance) {
return new AutoQueue<typename Arc::StateId>(fst, distance, ArcFilter());
}
};
template<class Arc, class ArcFilter>
struct QueueConstructor<NaturalShortestFirstQueue<typename Arc::StateId,
typename Arc::Weight>,
Arc, ArcFilter> {
// template<class Arc, class ArcFilter>
static NaturalShortestFirstQueue<typename Arc::StateId, typename Arc::Weight>
*Construct(const Fst<Arc> &fst,
const vector<typename Arc::Weight> *distance) {
return new NaturalShortestFirstQueue<typename Arc::StateId,
typename Arc::Weight>(*distance);
}
};
template<class Arc, class ArcFilter>
struct QueueConstructor<TopOrderQueue<typename Arc::StateId>, Arc, ArcFilter> {
// template<class Arc, class ArcFilter>
static TopOrderQueue<typename Arc::StateId> *Construct(
const Fst<Arc> &fst, const vector<typename Arc::Weight> *weights) {
return new TopOrderQueue<typename Arc::StateId>(fst, ArcFilter());
}
};
template<class Arc, class Queue>
void ShortestDistanceHelper(ShortestDistanceArgs1 *args) {
const Fst<Arc> &fst = *(args->arg1.GetFst<Arc>());
const ShortestDistanceOptions &opts = args->arg3;
vector<typename Arc::Weight> weights;
switch (opts.arc_filter_type) {
case ANY_ARC_FILTER: {
Queue *queue =
QueueConstructor<Queue, Arc, AnyArcFilter<Arc> >::Construct(
fst, &weights);
fst::ShortestDistanceOptions<Arc, Queue, AnyArcFilter<Arc> > sdopts(
queue, AnyArcFilter<Arc>(), opts.source, opts.delta);
ShortestDistance(fst, &weights, sdopts);
delete queue;
break;
}
case EPSILON_ARC_FILTER: {
Queue *queue =
QueueConstructor<Queue, Arc, AnyArcFilter<Arc> >::Construct(
fst, &weights);
fst::ShortestDistanceOptions<Arc, Queue,
EpsilonArcFilter<Arc> > sdopts(
queue, EpsilonArcFilter<Arc>(), opts.source, opts.delta);
ShortestDistance(fst, &weights, sdopts);
delete queue;
break;
}
case INPUT_EPSILON_ARC_FILTER: {
Queue *queue =
QueueConstructor<Queue, Arc, InputEpsilonArcFilter<Arc> >::Construct(
fst, &weights);
fst::ShortestDistanceOptions<Arc, Queue,
InputEpsilonArcFilter<Arc> > sdopts(
queue, InputEpsilonArcFilter<Arc>(), opts.source, opts.delta);
ShortestDistance(fst, &weights, sdopts);
delete queue;
break;
}
case OUTPUT_EPSILON_ARC_FILTER: {
Queue *queue =
QueueConstructor<Queue, Arc,
OutputEpsilonArcFilter<Arc> >::Construct(
fst, &weights);
fst::ShortestDistanceOptions<Arc, Queue,
OutputEpsilonArcFilter<Arc> > sdopts(
queue, OutputEpsilonArcFilter<Arc>(), opts.source, opts.delta);
ShortestDistance(fst, &weights, sdopts);
delete queue;
break;
}
}
// Copy the weights back
args->arg2->resize(weights.size());
for (unsigned i = 0; i < weights.size(); ++i) {
(*args->arg2)[i] = WeightClass(weights[i]);
}
}
template<class Arc>
void ShortestDistance(ShortestDistanceArgs1 *args) {
const ShortestDistanceOptions &opts = args->arg3;
typedef typename Arc::StateId StateId;
typedef typename Arc::Weight Weight;
// Must consider (opts.queue_type x opts.filter_type) options
switch (opts.queue_type) {
default:
FSTERROR() << "Unknown queue type." << opts.queue_type;
case AUTO_QUEUE:
ShortestDistanceHelper<Arc, AutoQueue<StateId> >(args);
return;
case FIFO_QUEUE:
ShortestDistanceHelper<Arc, FifoQueue<StateId> >(args);
return;
case LIFO_QUEUE:
ShortestDistanceHelper<Arc, LifoQueue<StateId> >(args);
return;
case SHORTEST_FIRST_QUEUE:
ShortestDistanceHelper<Arc,
NaturalShortestFirstQueue<StateId, Weight> >(args);
return;
case STATE_ORDER_QUEUE:
ShortestDistanceHelper<Arc, StateOrderQueue<StateId> >(args);
return;
case TOP_ORDER_QUEUE:
ShortestDistanceHelper<Arc, TopOrderQueue<StateId> >(args);
return;
}
}
// 2
typedef args::Package<const FstClass&, vector<WeightClass>*,
bool, double> ShortestDistanceArgs2;
template<class Arc>
void ShortestDistance(ShortestDistanceArgs2 *args) {
const Fst<Arc> &fst = *(args->arg1.GetFst<Arc>());
vector<typename Arc::Weight> distance;
ShortestDistance(fst, &distance, args->arg3, args->arg4);
// convert the typed weights back into weightclass
vector<WeightClass> *retval = args->arg2;
retval->resize(distance.size());
for (unsigned i = 0; i < distance.size(); ++i) {
(*retval)[i] = WeightClass(distance[i]);
}
}
// 3
typedef args::WithReturnValue<WeightClass,
const FstClass &> ShortestDistanceArgs3;
template<class Arc>
void ShortestDistance(ShortestDistanceArgs3 *args) {
const Fst<Arc> &fst = *(args->args.GetFst<Arc>());
args->retval = WeightClass(ShortestDistance(fst));
}
// 1
void ShortestDistance(const FstClass &fst, vector<WeightClass> *distance,
const ShortestDistanceOptions &opts);
// 2
void ShortestDistance(const FstClass &ifst, vector<WeightClass> *distance,
bool reverse = false, double delta = fst::kDelta);
#ifndef SWIG
// 3
WeightClass ShortestDistance(const FstClass &ifst);
#endif
} // namespace script
} // namespace fst
#endif // FST_SCRIPT_SHORTEST_DISTANCE_H_
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