fix unsigned

[1223421]

If a Counter64 has 1 in the first bit, an IntegerNegative error is raised. For unsigned values, this check is not needed. The bug is in the decode_array_uint function — why check the first bit for an unsigned value?

[chifflier]

Hi,
Counter64 is defined as (IMPLICIT) INTEGER with constraints, and INTEGER is encoded as following (in X.590):
The contents octets shall be a two’s complement binary number equal to the integer value [...]
This means that encoding an unsigned int with the first bit set is an invalid encoding, because this is reserved to encode negative numbers. Since this is invalid, this PR will be marked as wontfix.
That said, I also encountered some applications using this wrong encoding. One solution (more a workaround) is to force conversion to unsigned if bit 1 is set. Maybe we can also add a helper function to the API to force reading as unsigned?
If you are interested in this addition, please open a new PR, or just tell me and I will have a look.

[1223421]

I’m not a good enough programmer to add the described fix myself.
So basically, should it be a signed counter there?

Most likely, D-Link isn’t aware of this...