public async Task Encode(ReadOnlyMemory<byte>[] sources, int[] index, Memory<byte>[] repairs, int packetLength, int concurrency = 1, CancellationToken token = default)
{
if (sources == null) throw new ArgumentNullException(nameof(sources));
if (repairs == null) throw new ArgumentNullException(nameof(repairs));
if (index == null) throw new ArgumentNullException(nameof(index));
await Enumerable.Range(0, repairs.Length).ForEachAsync(row =>
{
return Task.Run(() =>
{
token.ThrowIfCancellationRequested();
// *remember* indices start at 0, k starts at 1.
if (index[row] < _k)
{
// < k, systematic so direct copy.
BytesOperations.Copy(sources[index[row]].Span, repairs[row].Span, packetLength);
}
else
{
// index[row] >= k && index[row] < n
int pos = index[row] * _k;
BytesOperations.Zero(repairs[row].Span.Slice(packetLength));
for (int col = 0; col < _k; col++)
{
token.ThrowIfCancellationRequested();
ReadSolomonMath.AddMul(sources[col].Span, repairs[row].Span, _encMatrix[pos + col], packetLength);
}
}
});
}, concurrency, token, false);
}
public ReedSolomon8(int k, int n, BufferPool bufferPool)
{
_k = k;
_n = n;
_bufferPool = bufferPool;
_encMatrix = ReadSolomonMath.CreateEncodeMatrix(k, n);
}
public async Task Decode(Memory<byte>[] packets, int[] index, int packetLength, int concurrency = 1, CancellationToken token = default)
{
if (packets == null) throw new ArgumentNullException(nameof(packets));
if (index == null) throw new ArgumentNullException(nameof(index));
Shuffle(packets, index, _k);
var decMatrix = ReadSolomonMath.CreateDecodeMatrix(_encMatrix, index, _k, _n);
// do the actual decoding..
var tempPackets = new byte[_k][];
await Enumerable.Range(0, _k).ForEachAsync(row =>
{
return Task.Run(() =>
{
token.ThrowIfCancellationRequested();
if (index[row] >= _k)
{
tempPackets[row] = _bufferPool.GetArrayPool().Rent(packetLength);
BytesOperations.Zero(tempPackets[row].AsSpan(0, packetLength));
for (int col = 0; col < _k; col++)
{
token.ThrowIfCancellationRequested();
ReadSolomonMath.AddMul(packets[col].Span, tempPackets[row], decMatrix[row * _k + col], packetLength);
}
}
});
}, concurrency, token, false);
token.ThrowIfCancellationRequested();
// move pkts to their final destination
for (int row = 0; row < _k; row++)
{
if (index[row] >= _k)
{
// only copy those actually decoded.
BytesOperations.Copy(tempPackets[row], packets[row].Span, packetLength);
index[row] = row;
_bufferPool.GetArrayPool().Return(tempPackets[row]);
}
}
}
internal static void LoadPureUnsafeMethods()
{
ReadSolomonMath.LoadPureUnsafeMethods();
}
internal static void LoadNativeMethods()
{
ReadSolomonMath.LoadNativeMethods();
}
