diff options
Diffstat (limited to 'xfa/fxbarcode/common/reedsolomon/BC_ReedSolomonDecoder.cpp')
| -rw-r--r-- | xfa/fxbarcode/common/reedsolomon/BC_ReedSolomonDecoder.cpp | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/xfa/fxbarcode/common/reedsolomon/BC_ReedSolomonDecoder.cpp b/xfa/fxbarcode/common/reedsolomon/BC_ReedSolomonDecoder.cpp new file mode 100644 index 0000000000..ff91c9ddc3 --- /dev/null +++ b/xfa/fxbarcode/common/reedsolomon/BC_ReedSolomonDecoder.cpp @@ -0,0 +1,221 @@ +// 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 "xfa/fxbarcode/common/reedsolomon/BC_ReedSolomonDecoder.h" + +#include <memory> +#include <utility> + +#include "xfa/fxbarcode/common/reedsolomon/BC_ReedSolomonGF256.h" +#include "xfa/fxbarcode/common/reedsolomon/BC_ReedSolomonGF256Poly.h" + +CBC_ReedSolomonDecoder::CBC_ReedSolomonDecoder(CBC_ReedSolomonGF256* field) { + m_field = field; +} +CBC_ReedSolomonDecoder::~CBC_ReedSolomonDecoder() {} +void CBC_ReedSolomonDecoder::Decode(CFX_Int32Array* received, + int32_t twoS, + int32_t& e) { + CBC_ReedSolomonGF256Poly poly; + poly.Init(m_field, received, e); + BC_EXCEPTION_CHECK_ReturnVoid(e); + CFX_Int32Array syndromeCoefficients; + syndromeCoefficients.SetSize(twoS); + FX_BOOL dataMatrix = FALSE; + FX_BOOL noError = TRUE; + for (int32_t i = 0; i < twoS; i++) { + int32_t eval = poly.EvaluateAt(m_field->Exp(dataMatrix ? i + 1 : i)); + syndromeCoefficients[twoS - 1 - i] = eval; + if (eval != 0) { + noError = FALSE; + } + } + if (noError) { + return; + } + CBC_ReedSolomonGF256Poly syndrome; + syndrome.Init(m_field, &syndromeCoefficients, e); + BC_EXCEPTION_CHECK_ReturnVoid(e); + std::unique_ptr<CBC_ReedSolomonGF256Poly> temp( + m_field->BuildMonomial(twoS, 1, e)); + BC_EXCEPTION_CHECK_ReturnVoid(e); + std::unique_ptr<CFX_PtrArray> sigmaOmega( + RunEuclideanAlgorithm(temp.get(), &syndrome, twoS, e)); + BC_EXCEPTION_CHECK_ReturnVoid(e); + std::unique_ptr<CBC_ReedSolomonGF256Poly> sigma( + (CBC_ReedSolomonGF256Poly*)(*sigmaOmega)[0]); + std::unique_ptr<CBC_ReedSolomonGF256Poly> omega( + (CBC_ReedSolomonGF256Poly*)(*sigmaOmega)[1]); + std::unique_ptr<CFX_Int32Array> errorLocations( + FindErrorLocations(sigma.get(), e)); + BC_EXCEPTION_CHECK_ReturnVoid(e); + std::unique_ptr<CFX_Int32Array> errorMagnitudes( + FindErrorMagnitudes(omega.get(), errorLocations.get(), dataMatrix, e)); + BC_EXCEPTION_CHECK_ReturnVoid(e); + for (int32_t k = 0; k < errorLocations->GetSize(); k++) { + int32_t position = + received->GetSize() - 1 - m_field->Log((*errorLocations)[k], e); + BC_EXCEPTION_CHECK_ReturnVoid(e); + if (position < 0) { + e = BCExceptionBadErrorLocation; + BC_EXCEPTION_CHECK_ReturnVoid(e); + } + (*received)[position] = CBC_ReedSolomonGF256::AddOrSubtract( + (*received)[position], (*errorMagnitudes)[k]); + } +} +CFX_PtrArray* CBC_ReedSolomonDecoder::RunEuclideanAlgorithm( + CBC_ReedSolomonGF256Poly* a, + CBC_ReedSolomonGF256Poly* b, + int32_t R, + int32_t& e) { + if (a->GetDegree() < b->GetDegree()) { + CBC_ReedSolomonGF256Poly* temp = a; + a = b; + b = temp; + } + std::unique_ptr<CBC_ReedSolomonGF256Poly> rLast(a->Clone(e)); + BC_EXCEPTION_CHECK_ReturnValue(e, NULL); + std::unique_ptr<CBC_ReedSolomonGF256Poly> r(b->Clone(e)); + BC_EXCEPTION_CHECK_ReturnValue(e, NULL); + std::unique_ptr<CBC_ReedSolomonGF256Poly> sLast(m_field->GetOne()->Clone(e)); + BC_EXCEPTION_CHECK_ReturnValue(e, NULL); + std::unique_ptr<CBC_ReedSolomonGF256Poly> s(m_field->GetZero()->Clone(e)); + BC_EXCEPTION_CHECK_ReturnValue(e, NULL); + std::unique_ptr<CBC_ReedSolomonGF256Poly> tLast(m_field->GetZero()->Clone(e)); + BC_EXCEPTION_CHECK_ReturnValue(e, NULL); + std::unique_ptr<CBC_ReedSolomonGF256Poly> t(m_field->GetOne()->Clone(e)); + BC_EXCEPTION_CHECK_ReturnValue(e, NULL); + while (r->GetDegree() >= R / 2) { + std::unique_ptr<CBC_ReedSolomonGF256Poly> rLastLast = std::move(rLast); + std::unique_ptr<CBC_ReedSolomonGF256Poly> sLastLast = std::move(sLast); + std::unique_ptr<CBC_ReedSolomonGF256Poly> tLastlast = std::move(tLast); + rLast = std::move(r); + sLast = std::move(s); + tLast = std::move(t); + if (rLast->IsZero()) { + e = BCExceptionR_I_1IsZero; + BC_EXCEPTION_CHECK_ReturnValue(e, NULL); + } + r.reset(rLastLast->Clone(e)); + BC_EXCEPTION_CHECK_ReturnValue(e, NULL); + std::unique_ptr<CBC_ReedSolomonGF256Poly> q(m_field->GetZero()->Clone(e)); + BC_EXCEPTION_CHECK_ReturnValue(e, NULL); + int32_t denominatorLeadingTerm = rLast->GetCoefficients(rLast->GetDegree()); + int32_t dltInverse = m_field->Inverse(denominatorLeadingTerm, e); + BC_EXCEPTION_CHECK_ReturnValue(e, NULL); + while (r->GetDegree() >= rLast->GetDegree() && !(r->IsZero())) { + int32_t degreeDiff = r->GetDegree() - rLast->GetDegree(); + int32_t scale = + m_field->Multiply(r->GetCoefficients(r->GetDegree()), dltInverse); + std::unique_ptr<CBC_ReedSolomonGF256Poly> build( + m_field->BuildMonomial(degreeDiff, scale, e)); + BC_EXCEPTION_CHECK_ReturnValue(e, NULL); + q.reset(q->AddOrSubtract(build.get(), e)); + BC_EXCEPTION_CHECK_ReturnValue(e, NULL); + std::unique_ptr<CBC_ReedSolomonGF256Poly> multiply( + rLast->MultiplyByMonomial(degreeDiff, scale, e)); + BC_EXCEPTION_CHECK_ReturnValue(e, NULL); + r.reset(r->AddOrSubtract(multiply.get(), e)); + BC_EXCEPTION_CHECK_ReturnValue(e, NULL); + } + std::unique_ptr<CBC_ReedSolomonGF256Poly> temp1( + q->Multiply(sLast.get(), e)); + BC_EXCEPTION_CHECK_ReturnValue(e, NULL); + s.reset(temp1->AddOrSubtract(sLastLast.get(), e)); + BC_EXCEPTION_CHECK_ReturnValue(e, NULL); + std::unique_ptr<CBC_ReedSolomonGF256Poly> temp5( + q->Multiply(tLast.get(), e)); + BC_EXCEPTION_CHECK_ReturnValue(e, NULL); + t.reset(temp5->AddOrSubtract(tLastlast.get(), e)); + BC_EXCEPTION_CHECK_ReturnValue(e, NULL); + } + int32_t sigmaTildeAtZero = t->GetCoefficients(0); + if (sigmaTildeAtZero == 0) { + e = BCExceptionIsZero; + BC_EXCEPTION_CHECK_ReturnValue(e, NULL); + } + int32_t inverse = m_field->Inverse(sigmaTildeAtZero, e); + BC_EXCEPTION_CHECK_ReturnValue(e, NULL); + std::unique_ptr<CBC_ReedSolomonGF256Poly> sigma(t->Multiply(inverse, e)); + BC_EXCEPTION_CHECK_ReturnValue(e, NULL); + std::unique_ptr<CBC_ReedSolomonGF256Poly> omega(r->Multiply(inverse, e)); + BC_EXCEPTION_CHECK_ReturnValue(e, NULL); + CFX_PtrArray* temp = new CFX_PtrArray; + temp->Add(sigma.release()); + temp->Add(omega.release()); + return temp; +} +CFX_Int32Array* CBC_ReedSolomonDecoder::FindErrorLocations( + CBC_ReedSolomonGF256Poly* errorLocator, + int32_t& e) { + int32_t numErrors = errorLocator->GetDegree(); + if (numErrors == 1) { + std::unique_ptr<CFX_Int32Array> temp(new CFX_Int32Array); + temp->Add(errorLocator->GetCoefficients(1)); + return temp.release(); + } + CFX_Int32Array* tempT = new CFX_Int32Array; + tempT->SetSize(numErrors); + std::unique_ptr<CFX_Int32Array> result(tempT); + int32_t ie = 0; + for (int32_t i = 1; i < 256 && ie < numErrors; i++) { + if (errorLocator->EvaluateAt(i) == 0) { + (*result)[ie] = m_field->Inverse(i, ie); + BC_EXCEPTION_CHECK_ReturnValue(e, NULL); + ie++; + } + } + if (ie != numErrors) { + e = BCExceptionDegreeNotMatchRoots; + BC_EXCEPTION_CHECK_ReturnValue(e, NULL); + } + return result.release(); +} +CFX_Int32Array* CBC_ReedSolomonDecoder::FindErrorMagnitudes( + CBC_ReedSolomonGF256Poly* errorEvaluator, + CFX_Int32Array* errorLocations, + FX_BOOL dataMatrix, + int32_t& e) { + int32_t s = errorLocations->GetSize(); + CFX_Int32Array* temp = new CFX_Int32Array; + temp->SetSize(s); + std::unique_ptr<CFX_Int32Array> result(temp); + for (int32_t i = 0; i < s; i++) { + int32_t xiInverse = m_field->Inverse(errorLocations->operator[](i), e); + BC_EXCEPTION_CHECK_ReturnValue(e, NULL); + int32_t denominator = 1; + for (int32_t j = 0; j < s; j++) { + if (i != j) { + denominator = m_field->Multiply( + denominator, CBC_ReedSolomonGF256::AddOrSubtract( + 1, m_field->Multiply(errorLocations->operator[](j), + xiInverse))); + } + } + int32_t temp = m_field->Inverse(denominator, temp); + BC_EXCEPTION_CHECK_ReturnValue(e, NULL); + (*result)[i] = + m_field->Multiply(errorEvaluator->EvaluateAt(xiInverse), temp); + } + return result.release(); +} |