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93 lines
3.2 KiB
93 lines
3.2 KiB
4 months ago
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// 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_ReedSolomon.h"
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#include <memory>
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#include <utility>
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#include "fxbarcode/common/reedsolomon/BC_ReedSolomonGF256.h"
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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_ReedSolomonEncoder::CBC_ReedSolomonEncoder(CBC_ReedSolomonGF256* field)
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: m_field(field) {
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m_cachedGenerators.push_back(pdfium::MakeUnique<CBC_ReedSolomonGF256Poly>(
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m_field.Get(), std::vector<int32_t>{1}));
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}
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CBC_ReedSolomonEncoder::~CBC_ReedSolomonEncoder() {}
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CBC_ReedSolomonGF256Poly* CBC_ReedSolomonEncoder::BuildGenerator(
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size_t degree) {
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if (degree >= m_cachedGenerators.size()) {
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CBC_ReedSolomonGF256Poly* lastGenerator = m_cachedGenerators.back().get();
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for (size_t d = m_cachedGenerators.size(); d <= degree; ++d) {
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CBC_ReedSolomonGF256Poly temp_poly(m_field.Get(),
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{1, m_field->Exp(d - 1)});
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auto nextGenerator = lastGenerator->Multiply(&temp_poly);
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if (!nextGenerator)
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return nullptr;
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lastGenerator = nextGenerator.get();
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m_cachedGenerators.push_back(std::move(nextGenerator));
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}
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}
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return m_cachedGenerators[degree].get();
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}
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bool CBC_ReedSolomonEncoder::Encode(std::vector<int32_t>* toEncode,
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size_t ecBytes) {
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if (ecBytes == 0)
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return false;
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if (toEncode->size() <= ecBytes)
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return false;
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CBC_ReedSolomonGF256Poly* generator = BuildGenerator(ecBytes);
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if (!generator)
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return false;
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size_t dataBytes = toEncode->size() - ecBytes;
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std::vector<int32_t> infoCoefficients(dataBytes);
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for (size_t x = 0; x < dataBytes; x++)
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infoCoefficients[x] = (*toEncode)[x];
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CBC_ReedSolomonGF256Poly info(m_field.Get(), infoCoefficients);
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auto infoTemp = info.MultiplyByMonomial(ecBytes, 1);
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if (!infoTemp)
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return false;
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auto remainder = infoTemp->Divide(generator);
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if (!remainder)
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return false;
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const auto& coefficients = remainder->GetCoefficients();
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size_t numZeroCoefficients =
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ecBytes > coefficients.size() ? ecBytes - coefficients.size() : 0;
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for (size_t i = 0; i < numZeroCoefficients; i++)
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(*toEncode)[dataBytes + i] = 0;
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for (size_t y = 0; y < coefficients.size(); y++)
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(*toEncode)[dataBytes + numZeroCoefficients + y] = coefficients[y];
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return true;
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}
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