newbie sending hex values over UDP socket

Grant Edwards grante at visi.com
Tue Sep 14 21:03:43 CEST 2004


On 2004-09-14, Bill Seitz <fluxent at yahoo.com> wrote:

>> Excellent - now how about calculating a parity-check byte?
>
> Here's the definition of the parity byte:
>
> The column parity is one (1) byte.  The eight bits of data in this
> byte re¬flect the odd parity of all corresponding bits in the block;
> i.e. bit 8 of the Column Parity byte is the odd parity of all bit 8's
> in the entire block.
> Column parity will be calculated by the sender as follows:
>
> (a)	Begin with the value 255.
>
> (b)	Exclusive OR the current value with the value of the first (or
> next) data byte beginning with the header byte.  Repeat until all
> bytes up to, but not includ¬ing, the parity byte have been used.
>
> (c)	Send the result in the column parity position.

# assume "s" is the data for which we want a parity byte

parityByte = chr(reduce(operator.__xor__,map(ord,s)))

-- 
Grant Edwards                   grante             Yow!  NOW, I'm supposed
                                  at               to SCRAMBLE two, and HOLD
                               visi.com            th' MAYO!!



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