Thoughts about revisiting fmt/189 signature...

[ross-spencer]

I received a bug report on my skeleton-test-suite generator recently. The issue known, surrounding the placement of the two byte-sequences in fmt/189: http://www.nationalarchives.gov.uk/pronom/fmt/189

I've described my comments on it in the issue log: https://github.com/exponential-decay/skeleton-test-suite-generator/issues/1  

In short, I wonder if the PRONOM team could consider at a minimum, swapping the two byte sequences around, by re-writing them in sequence in PRONOM, and/or replacing the two sequences for one. 

My initial thinking is that this would have equivalent functionality:

Position type   Absolute from BOF

Offset          0

Byte-order      Little-endian

Value           504B0304{0-18}504B0102{0-18}504B0506{0-18}5B436F6E74656E745F54797065735D2E786D6C20A2

To the original:

Sequence one:

Position type   Absolute from BOF

Offset          30

Byte order      Little-endian

Value           5B436F6E74656E745F54797065735D2E786D6C20A2

Sequence two:

Position type   Absolute from BOF

Offset          0

Byte order      Little-endian

Value           504B0304*504B0102*504B0506

My working might be a bit rough, an approximation. A variation on the sequence above might certainly satisfy the requirement. 

The benefit might be small in this instance so it is appreciated that it wouldn't be top priority. 

[Dclipsham]

Thanks Ross,

This seems perfectly sensible. We'll need to test it quite heavily due to the weight of dependencies fmt/189 clearly has, but all going well I'm sure we can do this for the next release.

David

[Ross Spencer]

A very swift response! Many thanks David. Looking forward to hearing how it goes. 

Cheers,

Ross

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[Dclipsham]

Hi Ross, we've spoken offline, but just to confirm, we'll be modifying fmt/189 in the next release, due 27 February. We'll end up with a single signature, which will look like this:

BOF, offset 0,

504B0304{26}5B436F6E74656E745F54797065735D2E786D6C20A2*504B0102*504B0506

I hope this resolves the problem.

David