packed structures usefulness

[Marco Maggi]

Ciao,
  I am in the position to add, with relatively
little effort, a module to GEE to handle
packed data structures. This means that,
as example of a still unimplemented API, doing:

(define *triplet*
  (make-gstruct-type '((one . int)
               (two . double)
               (three . (int64 . 3)))))

(define S (make-gstruct *triplet*))

(set! (one S) 123)
(set! (two S) 1.2)
(set! (three S 2) 44)

one can define a SMOB whose internal
representation is equivalent to the C language
type:

struct triplet {
  int one;
  double two;
  int64_t three[3];
};

and then access its fields.

Remembering that, IMHO, there is no way to
mimic the C structure fields alignment from a
Scheme level inteface, I wonder if such a module
would be useful or not.

The conversion between Scheme level values and
C level values takes time, so I am not sure about
the value of the reduced memory usage.

Notice that I have already written a module
to implement variable-length vectors of C language
types, so that way of saving memory is already
available to me.

--
Marco Maggi

"Now feel the funk blast!"
Rage Against the Machine - "Calm like a bomb"