Re: Bit manipulation facilities in Ada

[Ole-Hjalmar Kristensen <ohk@maestro.clustra.com>]

dewarr@my-dejanews.com writes:

> > Robert T. Sagris wrote in message
> > <36573C4D.DA431821@physics.purdue.edu>...
> > I'm thinking about taking an Data Security and
> > Encryption course.
> > The language for programming projects is open to the
> > students.
> >
> > The Professor has already recommended C for its built in
> > Bit operators.
> > But I would like to try it in Ada, as I've never used in
> > a class.
> > I could use the practice.
> >
> > Robbi Sagris
> 
> 
> Ada is far better than C for this purpose. In addition to
> all the general (and quite correct) propaganda about the
> general superiority of Ada, there is one particular feature
> that is missing in Ada, namely packed bit arrays. In C you
> have to program this your self, as an array of bytes, which
> you then do bit manipulation on.
> 

Ever heard of bit fields in C?

> This is less efficient than the Ada code, results in much
> more obscure code, and is much more error prone.
> 
> Undoubtedly the Professor's recommendation simply comes
> from ignorance of this feature of Ada!
> 

Agreed.

> Regarding other facilities, Ada and C are pretty much
> equivalent in terms of low level facilities. Both give the
> choice of using bit operations on integer values, or of
> declaring records with bit fields.
> 
> But for the applications in question here, the packed array
> feature is a very critical one. You will find it far easier
> to program these problems in Ada, even if you are less
> familiar with Ada than with C (the effort of learning Ada
> will easily be repaid!).
> 
> Robert Dewar
> 
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