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// Copyright 2014 PDFium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
// Original code is licensed as follows:
/*
* Copyright 2007 ZXing authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "fxbarcode/common/reedsolomon/BC_ReedSolomon.h"
#include <memory>
#include <utility>
#include "fxbarcode/common/reedsolomon/BC_ReedSolomonGF256.h"
#include "fxbarcode/common/reedsolomon/BC_ReedSolomonGF256Poly.h"
#include "third_party/base/ptr_util.h"
CBC_ReedSolomonEncoder::CBC_ReedSolomonEncoder(CBC_ReedSolomonGF256* field)
: m_field(field) {}
CBC_ReedSolomonEncoder::~CBC_ReedSolomonEncoder() {}
void CBC_ReedSolomonEncoder::Init() {
m_cachedGenerators.push_back(
pdfium::MakeUnique<CBC_ReedSolomonGF256Poly>(m_field, 1));
}
CBC_ReedSolomonGF256Poly* CBC_ReedSolomonEncoder::BuildGenerator(
size_t degree) {
if (degree >= m_cachedGenerators.size()) {
CBC_ReedSolomonGF256Poly* lastGenerator = m_cachedGenerators.back().get();
for (size_t d = m_cachedGenerators.size(); d <= degree; ++d) {
std::vector<int32_t> temp = {1, m_field->Exp(d - 1)};
CBC_ReedSolomonGF256Poly temp_poly;
if (!temp_poly.Init(m_field, &temp))
return nullptr;
auto nextGenerator = lastGenerator->Multiply(&temp_poly);
if (!nextGenerator)
return nullptr;
lastGenerator = nextGenerator.get();
m_cachedGenerators.push_back(std::move(nextGenerator));
}
}
return m_cachedGenerators[degree].get();
}
bool CBC_ReedSolomonEncoder::Encode(std::vector<int32_t>* toEncode,
size_t ecBytes) {
if (ecBytes == 0)
return false;
if (toEncode->size() <= ecBytes)
return false;
CBC_ReedSolomonGF256Poly* generator = BuildGenerator(ecBytes);
if (!generator)
return false;
size_t dataBytes = toEncode->size() - ecBytes;
std::vector<int32_t> infoCoefficients(dataBytes);
for (size_t x = 0; x < dataBytes; x++)
infoCoefficients[x] = (*toEncode)[x];
CBC_ReedSolomonGF256Poly info;
if (!info.Init(m_field, &infoCoefficients))
return false;
auto infoTemp = info.MultiplyByMonomial(ecBytes, 1);
if (!infoTemp)
return false;
auto remainder = infoTemp->Divide(generator);
if (!remainder)
return false;
const auto& coefficients = remainder->GetCoefficients();
size_t numZeroCoefficients =
ecBytes > coefficients.size() ? ecBytes - coefficients.size() : 0;
for (size_t i = 0; i < numZeroCoefficients; i++)
(*toEncode)[dataBytes + i] = 0;
for (size_t y = 0; y < coefficients.size(); y++)
(*toEncode)[dataBytes + numZeroCoefficients + y] = coefficients[y];
return true;
}
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