Date   : Sun, 12 Jun 2011 17:12:40 +0100
From   : info@... (Sprow)
Subject: Calculating CRCs

In article <4DF4E408.9030004@...>,
   Rick Murray <rick@...> wrote:
> On 12/06/2011 04:00, J.G.Harston wrote:
> > Sprow wrote:
> > > In the C implementation I don't see what
> > > crc &= 0xFFFFFFFF;
> > > does.
> > I'm not sure, that's from my original notes from the very first version
> > of BBCZip back in about 1997.
> 
> That clips a 32 bit unsigned value to a 32 bit unsigned value - which is 
> probably not going to be necessary unless you have 64 bit capacity (else 
> it'd just overflow and do this by itself...).

Quite. Since it's a CRC32 algorithm it would be a bit odd to use anything
but uint32_t for that variable, and in 1997 I think the only 64 bit machines
were probably working in the met office,
Sprow.