Re: Looking for Long Tooth...

[Christopher Fowler <cfowler@outpostsentinel.com>]

Another point is that everytime you use a boolean in Java, you could
store that same info in 1 bit.  


On Wed, 2003-04-09 at 09:39, Henri Yandell wrote:
> 
> 
> On Wed, 9 Apr 2003, Scott P. Smith wrote:
> 
> > I am a little surprised by this question and the other one like it a few
> > weeks ago.  I have a sneaky feeling that I am helping a college student do
> > his homework, but I'll respond anyway.
> 
> I don't find it as surprising. Most of the bitwise manipulation I've come
> into direct contact with has not been very necessary, but just a result of
> old C habits being transferred to the language in question. Irritating
> things like:
> 
>  i ^= i;   or somesuch.
> 
> Many Java developers out there have not spent time working in C, and in
> many other languages there's not the need for the low-level bitwise stuff.
> 
> > There are infinitely many ways these operators can be useful.. But I'll just
> > give a few examples:
> 
> Major ones I've come into contact with are encryption algorithms and
> encoding algorithms. At work we encode a series of numbers into one long
> for transmission. I've found BigInteger to have surprising powers here at
> extracting the values. [for when our long got larger than a java long]
> 
> Having a look at the source to an encryption algorithm will see some very
> important uses of bit-shifting.
> 
> > * Data Compression - Many data compression algorithms compress byte streams
> > into bit streams.  To create (and later decode) the bit streams, you need
> > bitwise operators.
> >
> > * Non-Java Binary File I/O - When working with binary files that were
> > created in C, C++, etc. you will see a lot of use of things like unsigned
> > 16, and 32 bit values. Since Java doesn't support these, you have to use
> > bitwise operators to put the uint16 into a Java int32. And vise versa.
> 
> Apache's POI project is probably a good example of this. It reads MS
> Office formats and as far as I know is full of a need to bit-shift. Having
> a look at their source is probably an education.
> 
> > * Arbitrarily Precision Integer Math - Math packages that implement 64, 128,
> > 256 bit integers, etc.  These packages use bitwise operators (at least I
> > think they do).
> 
> BigInteger :)
> 
> 
> Hen