Mirror/aicodix___code
1
0
Fork 0
mirror of https://github.com/aicodix/code.git synced 2026-04-27 14:30:36 +00:00
Code Issues Projects Releases Packages Wiki Activity

added data_len argument for shortened codes

Browse source
This commit is contained in:
Ahmet Inan 2018-09-27 18:29:13 +02:00
commit 62819a5376
4 changed files with 60 additions and 39 deletions
Download patch file Download diff file Expand all files Collapse all files

32
reed_solomon_decoder.hh
View file

@ -33,33 +33,39 @@ private:
}
}
public:
int compute_syndromes(ValueType *data, ValueType *parity, ValueType *syndromes)
int compute_syndromes(ValueType *data, ValueType *parity, ValueType *syndromes, int data_len = K)
{
assert(0 < data_len && data_len <= K);
// $syndromes_i = code(pe^{FCR+i})$
ValueType coeff(data[0]);
for (int i = 0; i < NR; ++i)
syndromes[i] = coeff;
update_syndromes(data, syndromes, 1, K);
update_syndromes(data, syndromes, 1, data_len);
update_syndromes(parity, syndromes, 0, NP);
int nonzero = 0;
for (int i = 0; i < NR; ++i)
nonzero += !!syndromes[i];
return nonzero;
}
int operator()(ValueType *data, ValueType *parity, IndexType *erasures = 0, int erasures_count = 0)
int operator()(ValueType *data, ValueType *parity, IndexType *erasures = 0, int erasures_count = 0, int data_len = K)
{
assert(0 <= erasures_count && erasures_count <= NR);
assert(0 < data_len && data_len <= K);
if (0) {
for (int i = 0; i < erasures_count; ++i) {
int idx = (int)erasures[i];
if (idx < K)
if (idx < data_len)
data[idx] = ValueType(0);
else
parity[idx-K] = ValueType(0);
parity[idx-data_len] = ValueType(0);
}
}
if (erasures_count && data_len < K) {
for (int i = 0; i < erasures_count; ++i)
erasures[i] = IndexType((int)erasures[i] + K - data_len);
}
ValueType syndromes[NR];
if (!compute_syndromes(data, parity, syndromes))
if (!compute_syndromes(data, parity, syndromes, data_len))
return 0;
IndexType locations[NR];
ValueType magnitudes[NR];
@ -67,24 +73,24 @@ public:
if (count <= 0)
return count;
for (int i = 0; i < count; ++i) {
int idx = (int)locations[i];
if (idx < K)
int idx = (int)locations[i] + data_len - K;
if (idx < data_len)
data[idx] += magnitudes[i];
else
parity[idx-K] += magnitudes[i];
parity[idx-data_len] += magnitudes[i];
}
int corrections_count = 0;
for (int i = 0; i < count; ++i)
corrections_count += !!magnitudes[i];
return corrections_count;
}
int operator()(value_type *data, value_type *parity, value_type *erasures = 0, int erasures_count = 0)
int operator()(value_type *data, value_type *parity, value_type *erasures = 0, int erasures_count = 0, int data_len = K)
{
return (*this)(reinterpret_cast<ValueType *>(data), reinterpret_cast<ValueType *>(parity), reinterpret_cast<IndexType *>(erasures), erasures_count);
return (*this)(reinterpret_cast<ValueType *>(data), reinterpret_cast<ValueType *>(parity), reinterpret_cast<IndexType *>(erasures), erasures_count, data_len);
}
int compute_syndromes(value_type *data, value_type *parity, value_type *syndromes)
int compute_syndromes(value_type *data, value_type *parity, value_type *syndromes, int data_len = K)
{
return compute_syndromes(reinterpret_cast<ValueType *>(data), reinterpret_cast<ValueType *>(parity), reinterpret_cast<ValueType *>(syndromes));
return compute_syndromes(reinterpret_cast<ValueType *>(data), reinterpret_cast<ValueType *>(parity), reinterpret_cast<ValueType *>(syndromes), data_len);
}
};