[aprssig] TNC command formats
bherrman at spro.net
Thu Mar 17 00:29:00 CST 2005
At 03:25 PM 3/16/2005 -0800, Scott Miller wrote:
>match what you'd entered. You'd get ver<tab>SION. Not that bad, but the
>lack of a case-insensitive string compare makes it harder. If I think of a
>clean way to do it, I'll try.
Just a vague memory here and I don't have time to look it up, but....
I'm pretty sure that in ASCII the difference between an upper case letter
and a lower case letter is a single bit (set for lower case and clear for
upper). It shouldn't be too hard to mask that bit for the compare or apply
it to the added portion of the command in order to match the case. If you
choose to try and match the case I'd suggest borrowing the bit from the
last character the user entered.
i.e. if I enter He make the resulting command Help where if you used the
first character you would get HeLP.
p.s. Careful of numbers and special characters as they don't hold up if you
muck with that bit. (Interestingly numbers, at least, do in EBCDIC.)
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