Put n-1 repeated user types in one sequence field, and the last in another

[msarrel-work]

I'm working on this spec. Is there any way to make Filestore Responses and Fault Location separate fields?

Filestore Responses is a sequence of at least one TLV and is always present. Fault Location is only ever a single TLV and only present if Condition Code is not No Error. Right now, my ugly workaround is to put everything in a single field, called Dummy_TLV, and rely on the user writing in Python to check the value of Condition Code to know if the last TLV is a Fault Location TLV.

Note that the Filestore Responses TLVs all have a single type code in the TLV structure, and the Fault Location TLV has a different type code. Obviously, the TLV structures are variable length and therefore has a length field.

I've seen a bunch of existing issues on this topic, primarily #156. This comment in #156 is interesting, but it only seems to work if the repeated type is of fixed length, which my TLVs obviously are not. Also see this comment from #721. And also this microsoft_pe.ksy file referenced by @smx-smx.

[msarrel-work]

I think this problem really boils down to being able to count the number of TLVs in a repeated sequence. If I knew the number of TLVs in Filestore Responses, or the total number of TLVs in Filestore Responses plus Fault Location, this would be easy. Unfortunately, the data structure I'm modeling doesn't do that.