62 lines
2.0 KiB
C++
62 lines
2.0 KiB
C++
/* SPDX-License-Identifier: MIT */
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/* Copyright © 2022-present Max Bachmann */
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#pragma once
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#include "common.hpp"
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#include <algorithm>
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#include <cstddef>
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#include <limits>
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#include <vector>
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namespace rapidfuzz_reference {
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template <typename InputIt1, typename InputIt2>
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Matrix<size_t> osa_matrix(InputIt1 first1, InputIt1 last1, InputIt2 first2, InputIt2 last2)
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{
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size_t len1 = static_cast<size_t>(std::distance(first1, last1));
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size_t len2 = static_cast<size_t>(std::distance(first2, last2));
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Matrix<size_t> matrix(static_cast<size_t>(len1) + 1, static_cast<size_t>(len2) + 1);
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for (size_t i = 0; i <= len1; ++i)
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matrix(i, 0) = i;
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for (size_t i = 0; i <= len2; ++i)
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matrix(0, i) = i;
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for (size_t pos1 = 0; pos1 < len1; ++pos1) {
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for (size_t pos2 = 0; pos2 < len2; ++pos2) {
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size_t cost = (first1[pos1] == first2[pos2]) ? 0 : 1;
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matrix(pos1 + 1, pos2 + 1) =
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std::min({matrix(pos1, pos2 + 1) + 1, matrix(pos1 + 1, pos2) + 1, matrix(pos1, pos2) + cost});
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if (pos1 == 0 || pos2 == 0) continue;
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if (first1[pos1] != first2[pos2 - 1]) continue;
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if (first1[pos1 - 1] != first2[pos2]) continue;
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matrix(pos1 + 1, pos2 + 1) =
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std::min(matrix(pos1 + 1, pos2 + 1), matrix(pos1 - 1, pos2 - 1) + cost);
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}
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}
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return matrix;
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}
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template <typename InputIt1, typename InputIt2>
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size_t osa_distance(InputIt1 first1, InputIt1 last1, InputIt2 first2, InputIt2 last2,
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size_t score_cutoff = std::numeric_limits<size_t>::max())
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{
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auto matrix = osa_matrix(first1, last1, first2, last2);
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size_t dist = matrix.back();
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return (dist <= score_cutoff) ? dist : score_cutoff + 1;
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}
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template <typename Sentence1, typename Sentence2>
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size_t osa_distance(const Sentence1& s1, const Sentence2& s2,
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size_t score_cutoff = std::numeric_limits<size_t>::max())
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{
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return osa_distance(std::begin(s1), std::end(s1), std::begin(s2), std::end(s2), score_cutoff);
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}
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} // namespace rapidfuzz_reference
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