/// <summary>
/// Segment - sequence of stripes that is a multiple of (NumberOfColumns - 1),
/// and every (NumberOfColumns - 1) stripes in the sequence have the same stripeIndexInColumn
/// (Such sequence can be written to disk without reading the parity information first)
/// </summary>
public static void WriteSegment(Raid5Volume volume, DynamicDiskExtent newExtent, long firstStripeIndexInColumn, byte[] data)
{
List <DynamicColumn> newArray = new List <DynamicColumn>();
newArray.AddRange(volume.Columns);
newArray.Add(new DynamicColumn(newExtent));
int bytesPerStripe = volume.BytesPerStripe;
int stripesToWritePerColumn = (data.Length / bytesPerStripe) / (newArray.Count - 1);
int dataLengthPerColumn = stripesToWritePerColumn * bytesPerStripe;
byte[][] columnData = new byte[newArray.Count][];
for (int index = 0; index < columnData.Length; index++)
{
columnData[index] = new byte[dataLengthPerColumn];
}
Parallel.For(0, stripesToWritePerColumn, delegate(int stripeOffsetInColumn)
{
long stripeIndexInColumn = firstStripeIndexInColumn + stripeOffsetInColumn;
int parityColumnIndex = (newArray.Count - 1) - (int)(stripeIndexInColumn % newArray.Count);
byte[] parityData = new byte[bytesPerStripe];
for (int stripeVerticalIndex = 0; stripeVerticalIndex < newArray.Count - 1; stripeVerticalIndex++)
{
int columnIndex = (parityColumnIndex + 1 + stripeVerticalIndex) % newArray.Count;
long stripeOffsetInData = (stripeOffsetInColumn * (newArray.Count - 1) + stripeVerticalIndex) * bytesPerStripe;
#warning long array index
Array.Copy(data, (int)stripeOffsetInData, columnData[columnIndex], stripeOffsetInColumn * bytesPerStripe, bytesPerStripe);
parityData = Raid5Volume.XOR(parityData, columnData[columnIndex], stripeOffsetInColumn * bytesPerStripe, bytesPerStripe);
}
Array.Copy(parityData, 0, columnData[parityColumnIndex], stripeOffsetInColumn * bytesPerStripe, bytesPerStripe);
});
// write the data
long firstSectorIndexInColumn = firstStripeIndexInColumn * volume.SectorsPerStripe;
for (int columnIndex = 0; columnIndex < newArray.Count; columnIndex++)
{
newArray[columnIndex].WriteSectors(firstSectorIndexInColumn, columnData[columnIndex]);
}
}
