57 lines
1.2 KiB
C++
57 lines
1.2 KiB
C++
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/*
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* Copyright 2016 Nu-book Inc.
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* Copyright 2016 ZXing authors
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*/
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// SPDX-License-Identifier: Apache-2.0
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#include "PDFModulusGF.h"
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#include <stdexcept>
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namespace ZXing {
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namespace Pdf417 {
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ModulusGF::ModulusGF(int modulus, int generator) :
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_modulus(modulus),
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_zero(*this, { 0 }),
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_one(*this, { 1 })
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{
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#ifdef ZX_REED_SOLOMON_USE_MORE_MEMORY_FOR_SPEED
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_expTable.resize(modulus * 2, 0);
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#else
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_expTable.resize(modulus, 0);
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#endif
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_logTable.resize(modulus, 0);
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int x = 1;
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for (int i = 0; i < modulus; i++) {
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_expTable[i] = x;
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x = (x * generator) % modulus;
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}
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#ifdef ZX_REED_SOLOMON_USE_MORE_MEMORY_FOR_SPEED
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for (int i = modulus - 1; i < modulus * 2; ++i)
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_expTable[i] = _expTable[i - (modulus - 1)];
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#endif
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for (int i = 0; i < modulus - 1; i++) {
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_logTable[_expTable[i]] = i;
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}
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// logTable[0] == 0 but this should never be used
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}
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ModulusPoly
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ModulusGF::buildMonomial(int degree, int coefficient) const
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{
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if (degree < 0) {
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throw std::invalid_argument("degree < 0");
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}
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if (coefficient == 0) {
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return _zero;
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}
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std::vector<int> coefficients(degree + 1, 0);
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coefficients[0] = coefficient;
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return ModulusPoly(*this, coefficients);
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}
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} // Pdf417
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} // ZXing
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