/// <summary>
/// This function query the file and returns a list of allocated ranges (The non-zero ranges!)
/// Please note that the file can contain zero-written areas but if the is not defined
/// as sparse and/or the chunks are smaller than 64kb (or 128 kb if the chunk is not
/// located in a start of a 64 kb chunk) the query will recognize those areas as allocated ones.
/// PLEASE NOTE! This function is the only one that doesn't work well on 64-bit systems
/// </summary>
/// <param name="fs"></param>
/// <returns></returns>
public static List <FILE_ALLOCATED_RANGE_BUFFER> QueryAllocatedRanges(FileStream fs)
{
FILE_ALLOCATED_RANGE_BUFFER _queryRange;
_queryRange._offset = 0;
_queryRange._length = fs.Length;
FILE_ALLOCATED_RANGE_BUFFER[] _ranges = new FILE_ALLOCATED_RANGE_BUFFER[64];
List <FILE_ALLOCATED_RANGE_BUFFER> _resultList = new List <FILE_ALLOCATED_RANGE_BUFFER>();
bool _br = false;
int _bytesReturned;
int _errNumber;
do
{
_br = false; //In case this is not the first cycle of the loop
if (!DeviceIoControlQueryAllocatedRanges(fs.SafeFileHandle, FSCTL_QUERY_ALLOCATED_RANGES, ref _queryRange, Marshal.SizeOf(_queryRange), out _ranges[0], _ranges.Length * Marshal.SizeOf(_queryRange), out _bytesReturned, IntPtr.Zero))
{
/*If the error accors because there's some data left (the array was not big enough) the whole process will happen again and again untill all the data is transfered*/
if ((_errNumber = Marshal.GetLastWin32Error()) == ERROR_MORE_DATA)
{
_br = true;
}
else
{
throw new Win32Exception(_errNumber);
}
}
int _nBytes = _bytesReturned / Marshal.SizeOf(_queryRange);
for (int i = 0; i < _nBytes; i++)
{
FILE_ALLOCATED_RANGE_BUFFER _tempBuf;
_tempBuf._offset = _ranges[i]._offset;
_tempBuf._length = _ranges[i]._length;
_resultList.Add(_tempBuf);
}
if (_br)
{
_queryRange._offset = _ranges[_nBytes - 1]._offset + _ranges[_nBytes - 1]._length;
_queryRange._length = fs.Length - _queryRange._offset;
}
} while (_br);
return(_resultList);
}
static extern bool DeviceIoControlQueryAllocatedRanges([In] SafeFileHandle hDevice, [In] uint dwIoControlCode, [In] ref FILE_ALLOCATED_RANGE_BUFFER fAllocRangeBuffer, [In] int nInBufferSize, [Out] out FILE_ALLOCATED_RANGE_BUFFER fRanges, [In] int nOutBufferSize, out int lpBytesReturned, [In] IntPtr lpOverlapped);
/// <summary>
/// This function query the file and returns a list of allocated ranges (The non-zero ranges!)
/// Please note that the file can contain zero-written areas but if the is not defined
/// as sparse and/or the chunks are smaller than 64kb (or 128 kb if the chunk is not
/// located in a start of a 64 kb chunk) the query will recognize those areas as allocated ones.
/// PLEASE NOTE! This function is the only one that doesn't work well on 64-bit systems
/// </summary>
/// <param name="fs"></param>
/// <returns></returns>
public static List<FILE_ALLOCATED_RANGE_BUFFER> QueryAllocatedRanges(FileStream fs)
{
FILE_ALLOCATED_RANGE_BUFFER _queryRange;
_queryRange._offset = 0;
_queryRange._length = fs.Length;
FILE_ALLOCATED_RANGE_BUFFER[] _ranges = new FILE_ALLOCATED_RANGE_BUFFER[64];
List<FILE_ALLOCATED_RANGE_BUFFER> _resultList = new List<FILE_ALLOCATED_RANGE_BUFFER>();
bool _br = false;
int _bytesReturned;
int _errNumber;
do
{
_br = false; //In case this is not the first cycle of the loop
if (!DeviceIoControlQueryAllocatedRanges(fs.SafeFileHandle, FSCTL_QUERY_ALLOCATED_RANGES, ref _queryRange, Marshal.SizeOf(_queryRange), out _ranges[0], _ranges.Length * Marshal.SizeOf(_queryRange), out _bytesReturned, IntPtr.Zero))
{
/*If the error accors because there's some data left (the array was not big enough) the whole process will happen again and again untill all the data is transfered*/
if ((_errNumber = Marshal.GetLastWin32Error()) == ERROR_MORE_DATA)
_br = true;
else
{
throw new Win32Exception(_errNumber);
}
}
int _nBytes = _bytesReturned / Marshal.SizeOf(_queryRange);
for (int i = 0; i < _nBytes; i++)
{
FILE_ALLOCATED_RANGE_BUFFER _tempBuf;
_tempBuf._offset = _ranges[i]._offset;
_tempBuf._length = _ranges[i]._length;
_resultList.Add(_tempBuf);
}
if (_br)
{
_queryRange._offset = _ranges[_nBytes - 1]._offset + _ranges[_nBytes - 1]._length;
_queryRange._length = fs.Length - _queryRange._offset;
}
} while (_br);
return _resultList;
}
