/// <summary>
/// This method is used to read the record segment of the MFT itself.
/// Only after strapping the MFT we can use GetFileRecordSegment which relies on the MFT file record.
/// </summary>
private FileRecordSegment ReadFileRecordSegment(long mftStartLCN, long segmentNumber)
{
long sectorIndex = mftStartLCN * m_volume.SectorsPerCluster + segmentNumber * m_volume.SectorsPerFileRecordSegment;
byte[] bytes = m_volume.ReadSectors(sectorIndex, m_volume.SectorsPerFileRecordSegment);
FileRecordSegment result = new FileRecordSegment(bytes, 0, segmentNumber);
return(result);
}
public byte[] ReadSectors(long firstSectorIndex, int count)
{
int sectorsPerCluster = m_volume.SectorsPerCluster;
int bytesPerSector = m_volume.BytesPerSector;
long firstClusterVCN = firstSectorIndex / sectorsPerCluster;
long lastSectorIndexToRead = firstSectorIndex + count - 1;
long lastClusterVCNToRead = lastSectorIndexToRead / sectorsPerCluster;
if (firstClusterVCN < LowestVCN || firstClusterVCN > HighestVCN)
{
string message = String.Format("Cluster VCN {0}-{1} is not within the valid range ({2}-{3})", firstClusterVCN, lastClusterVCNToRead, LowestVCN, HighestVCN);
throw new ArgumentOutOfRangeException(message);
}
long highestSectorIndex = (HighestVCN + 1) * sectorsPerCluster - 1;
if (lastSectorIndexToRead > highestSectorIndex)
{
lastSectorIndexToRead = highestSectorIndex;
}
byte[] result = new byte[count * bytesPerSector];
ulong firstBytePosition = (ulong)firstSectorIndex * (uint)bytesPerSector;
if (firstBytePosition < ValidDataLength)
{
KeyValuePairList <long, int> sequence = m_attributeRecord.DataRunSequence.TranslateToLBN(firstSectorIndex, count, sectorsPerCluster);
long bytesRead = 0;
foreach (KeyValuePair <long, int> run in sequence)
{
byte[] data = m_volume.ReadSectors(run.Key, run.Value, m_contentType);
Array.Copy(data, 0, result, bytesRead, data.Length);
bytesRead += data.Length;
}
}
int numberOfBytesToReturn = count * bytesPerSector;
if (firstBytePosition + (uint)numberOfBytesToReturn > FileSize)
{
// If the last sector is only partially used or we have been asked to read beyond FileSize, trim result.
numberOfBytesToReturn = (int)(FileSize - (ulong)firstSectorIndex * (uint)bytesPerSector);
byte[] resultTrimmed = new byte[numberOfBytesToReturn];
Array.Copy(result, resultTrimmed, numberOfBytesToReturn);
result = resultTrimmed;
}
if (firstBytePosition < ValidDataLength && ValidDataLength < firstBytePosition + (uint)numberOfBytesToReturn)
{
// Zero-out bytes outside ValidDataLength
int numberOfValidBytesInResult = (int)(ValidDataLength - firstBytePosition);
ByteWriter.WriteBytes(result, numberOfValidBytesInResult, new byte[result.Length - numberOfValidBytesInResult]);
}
return(result);
}
/// <summary>
/// This method is used to read the record segment(s) of the MFT itself.
/// Only after strapping the MFT we can use GetFileRecordSegment which relies on the MFT file record.
/// </summary>
private FileRecordSegment ReadMftRecordSegment(long mftStartLCN, long segmentNumber)
{
long sectorIndex = mftStartLCN * m_volume.SectorsPerCluster + segmentNumber * m_volume.SectorsPerFileRecordSegment;
byte[] segmentBytes = m_volume.ReadSectors(sectorIndex, m_volume.SectorsPerFileRecordSegment, ContentType.MftData);
MultiSectorHelper.RevertUsaProtection(segmentBytes, 0);
FileRecordSegment result = new FileRecordSegment(segmentBytes, 0, segmentNumber);
return(result);
}
