/usr/include/fst/script/shortest-distance.h is in libfst-dev 1.6.3-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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// finite-state transducer library.
#ifndef FST_SCRIPT_SHORTEST_DISTANCE_H_
#define FST_SCRIPT_SHORTEST_DISTANCE_H_
#include <vector>
#include <fst/queue.h> // for QueueType
#include <fst/shortest-distance.h>
#include <fst/script/arg-packs.h>
#include <fst/script/fst-class.h>
#include <fst/script/prune.h> // for ArcFilterType
#include <fst/script/weight-class.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
using ShortestDistanceArgs1 =
args::Package<const FstClass &, std::vector<WeightClass> *,
const ShortestDistanceOptions &>;
template <class Queue, class Arc, class ArcFilter>
struct QueueConstructor {
static Queue *Construct(const Fst<Arc> &,
const std::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 std::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 std::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 std::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;
std::vector<typename Arc::Weight> weights;
switch (opts.arc_filter_type) {
case ANY_ARC_FILTER: {
std::unique_ptr<Queue> queue(QueueConstructor<Queue, Arc,
AnyArcFilter<Arc>>::Construct(fst, &weights));
fst::ShortestDistanceOptions<Arc, Queue, AnyArcFilter<Arc>> sdopts(
queue.get(), AnyArcFilter<Arc>(), opts.source, opts.delta);
ShortestDistance(fst, &weights, sdopts);
break;
}
case EPSILON_ARC_FILTER: {
std::unique_ptr<Queue> queue(QueueConstructor<Queue, Arc,
AnyArcFilter<Arc>>::Construct(fst, &weights));
fst::ShortestDistanceOptions<Arc, Queue, EpsilonArcFilter<Arc>>
sdopts(queue.get(), EpsilonArcFilter<Arc>(), opts.source, opts.delta);
ShortestDistance(fst, &weights, sdopts);
break;
}
case INPUT_EPSILON_ARC_FILTER: {
std::unique_ptr<Queue> queue(QueueConstructor<Queue, Arc,
InputEpsilonArcFilter<Arc>>::Construct(fst, &weights));
fst::ShortestDistanceOptions<Arc, Queue, InputEpsilonArcFilter<Arc>>
sdopts(queue.get(), InputEpsilonArcFilter<Arc>(), opts.source,
opts.delta);
ShortestDistance(fst, &weights, sdopts);
break;
}
case OUTPUT_EPSILON_ARC_FILTER: {
std::unique_ptr<Queue> queue(QueueConstructor<Queue, Arc,
OutputEpsilonArcFilter<Arc>>::Construct(fst, &weights));
fst::ShortestDistanceOptions<Arc, Queue, OutputEpsilonArcFilter<Arc>>
sdopts(queue.get(), OutputEpsilonArcFilter<Arc>(), opts.source,
opts.delta);
ShortestDistance(fst, &weights, sdopts);
break;
}
}
// Copies the weights back.
args->arg2->resize(weights.size());
for (auto i = 0; i < weights.size(); ++i) {
(*args->arg2)[i] = WeightClass(weights[i]);
}
}
template <class Arc>
void ShortestDistance(ShortestDistanceArgs1 *args) {
const ShortestDistanceOptions &opts = args->arg3;
using StateId = typename Arc::StateId;
using Weight = typename Arc::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
using ShortestDistanceArgs2 =
args::Package<const FstClass &, std::vector<WeightClass> *, bool, double>;
template <class Arc>
void ShortestDistance(ShortestDistanceArgs2 *args) {
const Fst<Arc> &fst = *(args->arg1.GetFst<Arc>());
std::vector<typename Arc::Weight> distance;
ShortestDistance(fst, &distance, args->arg3, args->arg4);
// Converts the typed weights back to WeightClass instances.
std::vector<WeightClass> *retval = args->arg2;
retval->resize(distance.size());
for (size_t i = 0; i < distance.size(); ++i)
(*retval)[i] = WeightClass(distance[i]);
}
// 1
void ShortestDistance(const FstClass &fst, std::vector<WeightClass> *distance,
const ShortestDistanceOptions &opts);
// 2
void ShortestDistance(const FstClass &ifst, std::vector<WeightClass> *distance,
bool reverse = false, double delta = fst::kDelta);
} // namespace script
} // namespace fst
#endif // FST_SCRIPT_SHORTEST_DISTANCE_H_
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