public unsafe void ReadExternalAttribute(
Win32API.NONRESIDENT_ATTRIBUTE *attr,
UInt64 vcn,
ulong count,
IntPtr buffer)
{
UInt64 lcn = 0, runcount = 0;
ulong readcount, left;
byte * bytes = (byte *)(buffer.ToPointer());
for (left = count; left > 0; left -= readcount)
{
FindRun(attr, vcn, ref lcn, ref runcount);
readcount = (Math.Min(runcount, left));
ulong n = readcount * bootb.BytesPerSector * bootb.SectorsPerCluster;
if (lcn == 0)
{
//memset(bytes, 0, n);
Win32API.ZeroMemory(new IntPtr(bytes), (int)n);
}
else
{
ReadLCN(lcn, readcount, (IntPtr)bytes);
}
vcn += readcount;
bytes += n;
}
//buffer = new IntPtr(bytes);
}
public unsafe bool FindRun(Win32API.NONRESIDENT_ATTRIBUTE *attr, UInt64 vcn, ref UInt64 lcn, ref UInt64 count)
{
byte *run = null;
lcn = 0;
ulong baseoff = attr->LowVCN;
if (vcn < attr->LowVCN || vcn > attr->HighVCN)
{
return(false);
}
for (run = (byte *)((byte *)(attr) + attr->RunArrayOffset); *run != 0; run += RunLength(run))
{
lcn += RunLCN(run);
count = RunCount(run);
if (baseoff <= vcn && vcn < baseoff + count)
{
lcn = RunLCN(run) == 0 ? 0 : lcn + vcn - baseoff;
count -= (vcn - baseoff);
return(true);
}
else
{
baseoff += count;
}
}
return(false);
}
public unsafe void ReadVCN(Win32API.FILE_RECORD_HEADER *file, Win32API.AttributeType type,
UInt64 vcn, ulong count, IntPtr buffer)
{
Win32API.NONRESIDENT_ATTRIBUTE *attr = (Win32API.NONRESIDENT_ATTRIBUTE *)FindAttribute(file, type, null);
ReadExternalAttribute(attr, vcn, count, buffer);
}
