public void WriteSectors(long firstSectorIndex, byte[] data)
{
int sectorCount;
long lastSectorIndexToWrite;
long lastClusterVCNToWrite;
int bytesPerSector = m_volume.BytesPerSector;
int sectorsPerCluster = m_volume.SectorsPerCluster;
ulong firstBytePosition = (ulong)firstSectorIndex * (uint)bytesPerSector;
ulong nextBytePosition = firstBytePosition + (uint)data.Length;
if (data.Length % bytesPerSector > 0)
{
int paddedLength = (int)Math.Ceiling((double)data.Length / bytesPerSector) * bytesPerSector;
// last sector could be partial, we must zero-fill it before write
sectorCount = paddedLength / bytesPerSector;
lastSectorIndexToWrite = firstSectorIndex + sectorCount - 1;
lastClusterVCNToWrite = lastSectorIndexToWrite / sectorsPerCluster;
if (lastClusterVCNToWrite == HighestVCN)
{
byte[] paddedData = new byte[paddedLength];
Array.Copy(data, paddedData, data.Length);
data = paddedData;
}
else
{
// only the last sector can be partial
throw new ArgumentException("Cannot write partial sector");
}
}
else
{
sectorCount = data.Length / bytesPerSector;
lastSectorIndexToWrite = firstSectorIndex + sectorCount - 1;
lastClusterVCNToWrite = lastSectorIndexToWrite / sectorsPerCluster;
}
long firstClusterVCN = firstSectorIndex / sectorsPerCluster;
if (firstClusterVCN < LowestVCN || lastClusterVCNToWrite > HighestVCN)
{
string message = String.Format("Cluster VCN {0}-{1} is not within the valid range ({2}-{3})", firstClusterVCN, lastClusterVCNToWrite, LowestVCN, HighestVCN);
throw new ArgumentOutOfRangeException(message);
}
if (firstBytePosition > ValidDataLength)
{
// We need to zero-fill all the the bytes up to ValidDataLength
long firstSectorIndexToFill = (long)(ValidDataLength / (uint)bytesPerSector);
int transferSizeInSectors = Settings.MaximumTransferSizeLBA;
for (long sectorIndexToFill = firstSectorIndexToFill; sectorIndexToFill < firstSectorIndex; sectorIndexToFill += transferSizeInSectors)
{
int sectorsToWrite = (int)Math.Min(transferSizeInSectors, firstSectorIndex - firstSectorIndexToFill);
byte[] fillData = new byte[sectorsToWrite * bytesPerSector];
if (sectorIndexToFill == firstSectorIndexToFill)
{
int bytesToRetain = (int)(ValidDataLength % (uint)bytesPerSector);
if (bytesToRetain > 0)
{
byte[] dataToRetain = ReadSectors(firstSectorIndexToFill, 1);
Array.Copy(dataToRetain, 0, fillData, 0, bytesToRetain);
}
}
WriteSectors(sectorIndexToFill, fillData);
}
}
KeyValuePairList <long, int> sequence = m_attributeRecord.DataRunSequence.TranslateToLBN(firstSectorIndex, sectorCount, sectorsPerCluster);
long bytesWritten = 0;
foreach (KeyValuePair <long, int> run in sequence)
{
byte[] sectors = new byte[run.Value * bytesPerSector];
Array.Copy(data, bytesWritten, sectors, 0, sectors.Length);
m_volume.WriteSectors(run.Key, sectors, m_contentType);
bytesWritten += sectors.Length;
}
if (nextBytePosition > ValidDataLength)
{
m_attributeRecord.ValidDataLength = nextBytePosition;
if (m_fileRecord != null)
{
m_volume.UpdateFileRecord(m_fileRecord);
}
}
}