Blackrock add block validation

[h-mayorquin]

This is a PR I made when working together @luiztauffer to figure out how to open a malformed file. According to the blackrock spec heach data block has a flag indicating the start of the data block:

This PR adds a check and provides detailed debugging information including file offset, block index, expected vs actual values, and corruption indicators.

I also improved the missing file error message which now specifically list which NSX files are missing and did other minor improvements like using f-string formatting for filename
construction, clearer variable naming (replacing ambiguous spec with spec_version and
dh with packet_header), etc.

[zm711]

This seems fine to me.

[zm711]

Good by me. I'll wait to see if @samuelgarcia or @alejoe91 want to take a quick look too.

[cboulay]

I've never used the header_flag so I can't speak to its validity or utility here. The rest of the changes are intended to simply be for readability but a couple of errors were introduced. Please see the inline comments and revise.

fixes needed

[cboulay]

Concerns addressed. Thanks.

[zm711]

I will still give Sam a chance to read this next week. At least at the maintenance meeting we can briefly discuss before merge.

We want a, b, and c variants in this PR.

[zm711]

Just to recap. Sam at the maintenance meeting said that he would prefer to ensure all file variants are handled since this PR would be at a release boundary. So we will confirm the header flag for other versions and incorporate that (or since this is put off we can discuss merging later this week--as long as we have a plan for the other variants).

[h-mayorquin]

Just to recap. Sam at the maintenance meeting said that he would prefer to ensure all file variants are handled since this PR would be at a release boundary. So we will confirm the header flag for other versions and incorporate that (or since this is put off we can discuss merging later this week--as long as we have a plan for the other variants).

This request does not make sense. I just check and the other variant is empty:

https://github.com/h-mayorquin/python-neo/blob/2240a29c4366fb3ed5dacadb54837004651ee35e/neo/rawio/blackrockrawio.py#L967-L973

No validation can be performed there.

[zm711]

Okay so that means everything is actually covered? I think the issue was that no one had worked on this recently enough to know if we needed to cover the other variants.

[h-mayorquin]

Okay so that means everything is actually covered? I think the issue was that no one had worked on this recently enough to know if we needed to cover the other variants.

Yes, my review indicates that everything that needs to be covered is covered.

[zm711]

@samuelgarcia I'll leave the merge to you. But if the other variants don't matter this should be ready finally.