Add method to get a BER encoded tag's number

[OmegaRelay]

Hello, this commit adds a method to get the tag number from a BER encoded tag, and modifies the tag test to include the new method.

Let me know what you think :)

[codecov]

Codecov Report

Attention: Patch coverage is 80.95238% with 4 lines in your changes missing coverage. Please review.

Project coverage is 35.04%. Comparing base (bd70605) to head (b612c60).
Report is 45 commits behind head on main.

Files with missing lines	Patch %	Lines
encoding/tlv/ber.go	80.95%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #39      +/-   ##
==========================================
- Coverage   36.70%   35.04%   -1.67%     
==========================================
  Files          25       27       +2     
  Lines        1531     1672     +141     
==========================================
+ Hits          562      586      +24     
- Misses        896     1026     +130     
+ Partials       73       60      -13     

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[stv0g]

Great addition 👍 I like it. What do you think about naming it just Number()? The tags number alone isn't BER specific, or is it?

It happens just that we use the BER encoding to for our internal representation for a Tag in a uint. We could also have used a struct, but decided for a unit as it's easier to declare a large set if tags as it happens in a lot of SmartCard applications.

[OmegaRelay]

Great addition 👍 I like it. What do you think about naming it just Number()? The tags number alone isn't BER specific, or is it?

It happens just that we use the BER encoding to for our internal representation for a Tag in a uint. We could also have used a struct, but decided for a unit as it's easier to declare a large set if tags as it happens in a lot of SmartCard applications.

Thanks for reviewing.
I see the reason behind using the uint instead of a struct but the intention behind this method is to be able to get the tag number specifically for BER encoded tags where the tag also contains the class and constructed bits. This method does not work for simple or compact tlv tags and therefore I named it BERNumber to specify usage.

Alternatively, we could seperate tag types where only the BERTag type implements the Number(), Class() and IsContstructed() methods?

[stv0g]

I see. Thanks for your contribution :)