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);
CBC_ReedSolomonGF256Poly* rsg = m_field->BuildMonomial(twoS, 1, e);
BC_EXCEPTION_CHECK_ReturnVoid(e);
CBC_AutoPtr<CBC_ReedSolomonGF256Poly> temp(rsg);
CFX_PtrArray* pa = RunEuclideanAlgorithm(temp.get(), &syndrome, twoS, e);
BC_EXCEPTION_CHECK_ReturnVoid(e);
CBC_AutoPtr<CFX_PtrArray> sigmaOmega(pa);
CBC_AutoPtr<CBC_ReedSolomonGF256Poly> sigma(
(CBC_ReedSolomonGF256Poly*)(*sigmaOmega)[0]);
CBC_AutoPtr<CBC_ReedSolomonGF256Poly> omega(
(CBC_ReedSolomonGF256Poly*)(*sigmaOmega)[1]);
CFX_Int32Array* ia1 = FindErrorLocations(sigma.get(), e);
BC_EXCEPTION_CHECK_ReturnVoid(e);
CBC_AutoPtr<CFX_Int32Array> errorLocations(ia1);
CFX_Int32Array* ia2 =
FindErrorMagnitudes(omega.get(), errorLocations.get(), dataMatrix, e);
BC_EXCEPTION_CHECK_ReturnVoid(e);
CBC_AutoPtr<CFX_Int32Array> errorMagnitudes(ia2);
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]);
}
}
void ReedSolomonDecoder::decode(ArrayRef<int> received, int twoS) {
Ref<GF256Poly> poly(new GF256Poly(field, received));
#ifdef DEBUG
cout << "decoding with poly " << *poly << "\n";
#endif
ArrayRef<int> syndromeCoefficients(new Array<int> (twoS));
#ifdef DEBUG
cout << "syndromeCoefficients array = " <<
syndromeCoefficients.array_ << "\n";
#endif
bool dataMatrix = (&field == &GF256::DATA_MATRIX_FIELD);
bool noError = true;
for (int i = 0; i < twoS; i++) {
int eval = poly->evaluateAt(field.exp(dataMatrix ? i + 1 : i));
syndromeCoefficients[syndromeCoefficients->size() - 1 - i] = eval;
if (eval != 0) {
noError = false;
}
}
if (noError) {
return;
}
Ref<GF256Poly> syndrome(new GF256Poly(field, syndromeCoefficients));
Ref<GF256Poly> monomial(field.buildMonomial(twoS, 1));
vector<Ref<GF256Poly> > sigmaOmega(runEuclideanAlgorithm(monomial, syndrome, twoS));
ArrayRef<int> errorLocations = findErrorLocations(sigmaOmega[0]);
ArrayRef<int> errorMagitudes = findErrorMagnitudes(sigmaOmega[1], errorLocations, dataMatrix);
for (unsigned i = 0; i < errorLocations->size(); i++) {
int position = received->size() - 1 - field.log(errorLocations[i]);
//TODO: check why the position would be invalid
if (position < 0 || (size_t)position >= received.size())
throw IllegalArgumentException("Invalid position (ReedSolomonDecoder)");
received[position] = GF256::addOrSubtract(received[position], errorMagitudes[i]);
}
}
void ReedSolomonDecoder::decode(ArrayRef<int> received, int twoS) {
Ref<GF256Poly> poly(new GF256Poly(field, received));
#ifdef DEBUG
cout << "decoding with poly " << *poly << "\n";
#endif
ArrayRef<int> syndromeCoefficients(new Array<int>(twoS));
#ifdef DEBUG
cout << "syndromeCoefficients array = " <<
syndromeCoefficients.array_ << "\n";
#endif
bool noError = true;
for (int i = 0; i < twoS; i++) {
int eval = poly->evaluateAt(field.exp(i));
syndromeCoefficients[syndromeCoefficients->size() - 1 - i] = eval;
if (eval != 0) {
noError = false;
}
}
if (noError) {
return;
}
Ref<GF256Poly> syndrome(new GF256Poly(field, syndromeCoefficients));
Ref<GF256Poly> monomial(field.buildMonomial(twoS, 1));
vector<Ref<GF256Poly> > sigmaOmega
(runEuclideanAlgorithm(monomial, syndrome, twoS));
ArrayRef<int> errorLocations = findErrorLocations(sigmaOmega[0]);
ArrayRef<int> errorMagitudes = findErrorMagnitudes(sigmaOmega[1],
errorLocations);
for (unsigned i = 0; i < errorLocations->size(); i++) {
int position = received->size() - 1 - field.log(errorLocations[i]);
received[position] = GF256::addOrSubtract(received[position],
errorMagitudes[i]);
}
}
