| // Copyright 2014 The PDFium Authors |
| // 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_ReedSolomonGF256Poly.h" |
| |
| #include <memory> |
| #include <utility> |
| |
| #include "core/fxcrt/fx_system.h" |
| #include "core/fxcrt/stl_util.h" |
| #include "fxbarcode/common/reedsolomon/BC_ReedSolomonGF256.h" |
| #include "third_party/base/check.h" |
| |
| CBC_ReedSolomonGF256Poly::CBC_ReedSolomonGF256Poly( |
| CBC_ReedSolomonGF256* field, |
| const std::vector<int32_t>& coefficients) |
| : m_field(field) { |
| DCHECK(m_field); |
| DCHECK(!coefficients.empty()); |
| if (coefficients.size() == 1 || coefficients.front() != 0) { |
| m_coefficients = coefficients; |
| return; |
| } |
| |
| size_t firstNonZero = 1; |
| while (firstNonZero < coefficients.size() && |
| coefficients[firstNonZero] == 0) { |
| firstNonZero++; |
| } |
| if (firstNonZero == coefficients.size()) { |
| m_coefficients = m_field->GetZero()->GetCoefficients(); |
| } else { |
| m_coefficients.resize(coefficients.size() - firstNonZero); |
| for (size_t i = firstNonZero, j = 0; i < coefficients.size(); i++, j++) |
| m_coefficients[j] = coefficients[i]; |
| } |
| } |
| |
| CBC_ReedSolomonGF256Poly::~CBC_ReedSolomonGF256Poly() = default; |
| |
| const std::vector<int32_t>& CBC_ReedSolomonGF256Poly::GetCoefficients() const { |
| return m_coefficients; |
| } |
| |
| int32_t CBC_ReedSolomonGF256Poly::GetDegree() const { |
| return fxcrt::CollectionSize<int32_t>(m_coefficients) - 1; |
| } |
| |
| bool CBC_ReedSolomonGF256Poly::IsZero() const { |
| return m_coefficients.front() == 0; |
| } |
| |
| int32_t CBC_ReedSolomonGF256Poly::GetCoefficients(int32_t degree) const { |
| return m_coefficients[m_coefficients.size() - 1 - degree]; |
| } |
| |
| std::unique_ptr<CBC_ReedSolomonGF256Poly> CBC_ReedSolomonGF256Poly::Clone() |
| const { |
| return std::make_unique<CBC_ReedSolomonGF256Poly>(m_field, m_coefficients); |
| } |
| |
| std::unique_ptr<CBC_ReedSolomonGF256Poly> |
| CBC_ReedSolomonGF256Poly::AddOrSubtract(const CBC_ReedSolomonGF256Poly* other) { |
| if (IsZero()) |
| return other->Clone(); |
| if (other->IsZero()) |
| return Clone(); |
| |
| std::vector<int32_t> smallerCoefficients = m_coefficients; |
| std::vector<int32_t> largerCoefficients = other->GetCoefficients(); |
| if (smallerCoefficients.size() > largerCoefficients.size()) |
| std::swap(smallerCoefficients, largerCoefficients); |
| |
| std::vector<int32_t> sumDiff(largerCoefficients.size()); |
| size_t lengthDiff = largerCoefficients.size() - smallerCoefficients.size(); |
| for (size_t i = 0; i < lengthDiff; ++i) |
| sumDiff[i] = largerCoefficients[i]; |
| |
| for (size_t i = lengthDiff; i < largerCoefficients.size(); ++i) { |
| sumDiff[i] = CBC_ReedSolomonGF256::AddOrSubtract( |
| smallerCoefficients[i - lengthDiff], largerCoefficients[i]); |
| } |
| return std::make_unique<CBC_ReedSolomonGF256Poly>(m_field, sumDiff); |
| } |
| |
| std::unique_ptr<CBC_ReedSolomonGF256Poly> CBC_ReedSolomonGF256Poly::Multiply( |
| const CBC_ReedSolomonGF256Poly* other) { |
| if (IsZero() || other->IsZero()) |
| return m_field->GetZero()->Clone(); |
| |
| const std::vector<int32_t>& aCoefficients = m_coefficients; |
| const std::vector<int32_t>& bCoefficients = other->GetCoefficients(); |
| size_t aLength = aCoefficients.size(); |
| size_t bLength = bCoefficients.size(); |
| std::vector<int32_t> product(aLength + bLength - 1); |
| for (size_t i = 0; i < aLength; i++) { |
| int32_t aCoeff = aCoefficients[i]; |
| for (size_t j = 0; j < bLength; j++) { |
| product[i + j] = CBC_ReedSolomonGF256::AddOrSubtract( |
| product[i + j], m_field->Multiply(aCoeff, bCoefficients[j])); |
| } |
| } |
| return std::make_unique<CBC_ReedSolomonGF256Poly>(m_field, product); |
| } |
| |
| std::unique_ptr<CBC_ReedSolomonGF256Poly> |
| CBC_ReedSolomonGF256Poly::MultiplyByMonomial(int32_t degree, |
| int32_t coefficient) const { |
| if (degree < 0) |
| return nullptr; |
| if (coefficient == 0) |
| return m_field->GetZero()->Clone(); |
| |
| size_t size = m_coefficients.size(); |
| std::vector<int32_t> product(size + degree); |
| for (size_t i = 0; i < size; i++) |
| product[i] = m_field->Multiply(m_coefficients[i], coefficient); |
| |
| return std::make_unique<CBC_ReedSolomonGF256Poly>(m_field, product); |
| } |
| |
| std::unique_ptr<CBC_ReedSolomonGF256Poly> CBC_ReedSolomonGF256Poly::Divide( |
| const CBC_ReedSolomonGF256Poly* other) { |
| if (other->IsZero()) |
| return nullptr; |
| |
| auto quotient = m_field->GetZero()->Clone(); |
| if (!quotient) |
| return nullptr; |
| auto remainder = Clone(); |
| if (!remainder) |
| return nullptr; |
| |
| int32_t denominatorLeadingTerm = other->GetCoefficients(other->GetDegree()); |
| absl::optional<int32_t> inverseDenominatorLeadingTeam = |
| m_field->Inverse(denominatorLeadingTerm); |
| if (!inverseDenominatorLeadingTeam.has_value()) |
| return nullptr; |
| |
| while (remainder->GetDegree() >= other->GetDegree() && !remainder->IsZero()) { |
| int32_t degreeDifference = remainder->GetDegree() - other->GetDegree(); |
| int32_t scale = |
| m_field->Multiply(remainder->GetCoefficients((remainder->GetDegree())), |
| inverseDenominatorLeadingTeam.value()); |
| auto term = other->MultiplyByMonomial(degreeDifference, scale); |
| if (!term) |
| return nullptr; |
| auto iteratorQuotient = m_field->BuildMonomial(degreeDifference, scale); |
| if (!iteratorQuotient) |
| return nullptr; |
| quotient = quotient->AddOrSubtract(iteratorQuotient.get()); |
| if (!quotient) |
| return nullptr; |
| remainder = remainder->AddOrSubtract(term.get()); |
| if (!remainder) |
| return nullptr; |
| } |
| return remainder; |
| } |