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handle data and parity seperate in both BCH and RS

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This commit is contained in:
Ahmet Inan 2018-09-27 12:29:15 +02:00
commit f545b5d6ab
8 changed files with 145 additions and 105 deletions
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37
reed_solomon_decoder.hh
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@ -33,47 +33,58 @@ private:
}
}
public:
int compute_syndromes(ValueType *code, ValueType *syndromes)
int compute_syndromes(ValueType *data, ValueType *parity, ValueType *syndromes)
{
// $syndromes_i = code(pe^{FCR+i})$
ValueType coeff(code[0]);
ValueType coeff(data[0]);
for (int i = 0; i < NR; ++i)
syndromes[i] = coeff;
update_syndromes(code, syndromes, 1, N);
update_syndromes(data, syndromes, 1, K);
update_syndromes(parity, syndromes, 0, NP);
int nonzero = 0;
for (int i = 0; i < NR; ++i)
nonzero += !!syndromes[i];
return nonzero;
}
int operator()(ValueType *code, IndexType *erasures = 0, int erasures_count = 0)
int operator()(ValueType *data, ValueType *parity, IndexType *erasures = 0, int erasures_count = 0)
{
assert(0 <= erasures_count && erasures_count <= NR);
if (0) {
for (int i = 0; i < erasures_count; ++i)
code[(int)erasures[i]] = ValueType(0);
for (int i = 0; i < erasures_count; ++i) {
int idx = (int)erasures[i];
if (idx < K)
data[idx] = ValueType(0);
else
parity[idx-K] = ValueType(0);
}
}
ValueType syndromes[NR];
if (!compute_syndromes(code, syndromes))
if (!compute_syndromes(data, parity, syndromes))
return 0;
IndexType locations[NR];
ValueType magnitudes[NR];
int count = algorithm(syndromes, locations, magnitudes, erasures, erasures_count);
if (count <= 0)
return count;
for (int i = 0; i < count; ++i)
code[(int)locations[i]] += magnitudes[i];
for (int i = 0; i < count; ++i) {
int idx = (int)locations[i];
if (idx < K)
data[idx] += magnitudes[i];
else
parity[idx-K] += magnitudes[i];
}
int corrections_count = 0;
for (int i = 0; i < count; ++i)
corrections_count += !!magnitudes[i];
return corrections_count;
}
int operator()(value_type *code, value_type *erasures = 0, int erasures_count = 0)
int operator()(value_type *data, value_type *parity, value_type *erasures = 0, int erasures_count = 0)
{
return (*this)(reinterpret_cast<ValueType *>(code), reinterpret_cast<IndexType *>(erasures), erasures_count);
return (*this)(reinterpret_cast<ValueType *>(data), reinterpret_cast<ValueType *>(parity), reinterpret_cast<IndexType *>(erasures), erasures_count);
}
int compute_syndromes(value_type *code, value_type *syndromes)
int compute_syndromes(value_type *data, value_type *parity, value_type *syndromes)
{
return compute_syndromes(reinterpret_cast<ValueType *>(code), reinterpret_cast<ValueType *>(syndromes));
return compute_syndromes(reinterpret_cast<ValueType *>(data), reinterpret_cast<ValueType *>(parity), reinterpret_cast<ValueType *>(syndromes));
}
};