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37 lines
910 B
37 lines
910 B
/*
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Copyright (c) 2020 tevador <tevador@gmail.com>
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All rights reserved.
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*/
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#include "reed_solomon_code.hpp"
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#include <cassert>
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reed_solomon_code::reed_solomon_code(unsigned check_digits) : generator(1, 0) {
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for (unsigned i = 0; i < check_digits; ++i) {
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gf_poly binom = gf_poly(1, 1);
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binom[0] = gf_elem(i + 1).exp();
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generator *= binom;
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}
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assert(generator.degree() == check_digits);
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}
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void reed_solomon_code::encode(gf_poly& data) const {
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data *= gf_poly(generator.degree());
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gf_poly rem;
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gf_poly::div_rem(data, generator, rem);
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data -= rem;
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}
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bool reed_solomon_code::check(const gf_poly& message) const {
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auto syndrome = get_syndrome(message);
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return syndrome.is_zero();
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}
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gf_poly reed_solomon_code::get_syndrome(const gf_poly& message) const {
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gf_poly syndrome;
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for (unsigned i = 1; i <= generator.degree(); ++i) {
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syndrome[i - 1] = message(gf_elem(i).exp());
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}
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return syndrome;
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}
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