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95 lines
2.6 KiB
95 lines
2.6 KiB
// Copyright 2014 PDFium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
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// Original code is licensed as follows:
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/*
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* Copyright 2007 ZXing authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "fxbarcode/common/reedsolomon/BC_ReedSolomonGF256.h"
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#include <vector>
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#include "fxbarcode/common/reedsolomon/BC_ReedSolomonGF256Poly.h"
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#include "third_party/base/ptr_util.h"
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CBC_ReedSolomonGF256::CBC_ReedSolomonGF256(int32_t primitive) {
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int32_t x = 1;
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for (int32_t j = 0; j < 256; j++) {
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m_expTable[j] = x;
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x <<= 1;
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if (x >= 0x100) {
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x ^= primitive;
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}
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}
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for (int32_t i = 0; i < 255; i++) {
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m_logTable[m_expTable[i]] = i;
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}
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m_logTable[0] = 0;
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}
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void CBC_ReedSolomonGF256::Init() {
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m_zero = pdfium::MakeUnique<CBC_ReedSolomonGF256Poly>(
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this, std::vector<int32_t>{0});
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m_one = pdfium::MakeUnique<CBC_ReedSolomonGF256Poly>(this,
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std::vector<int32_t>{1});
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}
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CBC_ReedSolomonGF256::~CBC_ReedSolomonGF256() {}
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std::unique_ptr<CBC_ReedSolomonGF256Poly> CBC_ReedSolomonGF256::BuildMonomial(
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int32_t degree,
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int32_t coefficient) {
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if (degree < 0)
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return nullptr;
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if (coefficient == 0)
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return m_zero->Clone();
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std::vector<int32_t> coefficients(degree + 1);
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coefficients[0] = coefficient;
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return pdfium::MakeUnique<CBC_ReedSolomonGF256Poly>(this, coefficients);
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}
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// static
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int32_t CBC_ReedSolomonGF256::AddOrSubtract(int32_t a, int32_t b) {
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return a ^ b;
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}
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int32_t CBC_ReedSolomonGF256::Exp(int32_t a) {
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return m_expTable[a];
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}
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Optional<int32_t> CBC_ReedSolomonGF256::Inverse(int32_t a) {
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if (a == 0)
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return {};
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return m_expTable[255 - m_logTable[a]];
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}
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int32_t CBC_ReedSolomonGF256::Multiply(int32_t a, int32_t b) {
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if (a == 0 || b == 0) {
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return 0;
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}
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if (a == 1) {
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return b;
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}
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if (b == 1) {
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return a;
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}
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return m_expTable[(m_logTable[a] + m_logTable[b]) % 255];
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}
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