win32file.DeviceIoControl(FSCTL_GET_RETRIEVAL_POINTERS)

[Jim]

I'm not sure how to perform this operation in Python. The difficulty is
in knowing the size of the output buffer: if it is too small, I get an
"insufficient buffer" exception; too large, and I get an "end of file"
exception. In neither case is any partial data available.

I'd rather not resort to a binary seach...

 

[=?ISO-8859-1?Q?=22Martin_v=2E_L=F6wis=22?=]

I'm not sure how to perform this operation in Python. The difficulty is
in knowing the size of the output buffer: if it is too small, I get an
"insufficient buffer" exception; too large, and I get an "end of file"
exception. In neither case is any partial data available.

What precisely is the "end of file" exception you are getting. Looking
at

http://msdn.microsoft.com/library/d...us/fileio/fs/fsctl_get_retrieval_pointers.asp

I'd say it is

ERROR_HANDLE_EOF The volume is an NTFS file system volume and the
requested starting VCN is past the end of the file.

So my guess is you should just pass a smaller starting VCN.

Regards,
Martin

 

[Jim]

Mea culpa: files with *no* clusters return the end-of-file error.