distance.cpp

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#include <cstdint>
 
#include "liblevenshtein/transducer/distance.h"
#include "liblevenshtein/transducer/position.h"
#include "liblevenshtein/transducer/state_iterator.h"
 
namespace liblevenshtein {
 
template <>
auto distance<Algorithm::STANDARD>(State *state, std::size_t query_length)
    -> std::size_t {
  std::size_t min_distance = SIZE_MAX;
  for (Position *position : *state) {
    std::size_t i = position->term_index();
    std::size_t e = position->num_errors();
    std::size_t distance = query_length - i + e;
    if (distance < min_distance) {
      min_distance = distance;
    }
  }
  return min_distance;
}
 
template <>
auto distance<Algorithm::TRANSPOSITION>(State *state, std::size_t query_length)
    -> std::size_t {
  std::size_t min_distance = SIZE_MAX;
  for (Position *position : *state) {
    if (!position->is_special()) {
      std::size_t i = position->term_index();
      std::size_t e = position->num_errors();
      std::size_t distance = query_length - i + e;
      if (distance < min_distance) {
        min_distance = distance;
      }
    }
  }
  return min_distance;
}
 
template <>
auto distance<Algorithm::MERGE_AND_SPLIT>(State *state,
                                          std::size_t query_length)
    -> std::size_t {
  std::size_t min_distance = SIZE_MAX;
  for (Position *position : *state) {
    if (!position->is_special()) {
      std::size_t i = position->term_index();
      std::size_t e = position->num_errors();
      std::size_t distance = query_length - i + e;
      if (distance < min_distance) {
        min_distance = distance;
      }
    }
  }
  return min_distance;
}
 
} // namespace liblevenshtein