From: Kurt Dresner <omega697@...>
Date: 2004-11-23T05:49:53+09:00
Subject: Re: SWIG and Arrays (of ints)

So here's what I have right now.  The only thing that's missing is the
stuff to fix the last function.

%module unh_cmac
%include typemaps.i

#define	ALBUS        65
#define	RECTANGULAR  82
#define	LINEAR       76
#define	SPLINE       83
#define	CUSTOM       67
#define	VTRUE        1
#define	VFALSE       0

%typemap(ruby,in) (int num_state, int *qnt_state) {
  int i;
  if (!rb_obj_is_kind_of($input,rb_cArray))
    rb_raise(rb_eArgError, "Expected Array of Integers");
  $1 = RARRAY($input)->len;
  $2 = malloc($1*sizeof(int));
  for (i=0; i<$1; ++i)
    ($2)[i] = NUM2INT(RARRAY($input)->ptr[i]);
}
%typemap(freearg) (int size, int *ary) {
   if ($2) free($2);
}
%typemap(ruby,out) int {
  if($1 == 0) {
    $result = Qnil;
  } else {
    $result = INT2NUM($1);
  }
}

int allocate_cmac(int num_state, int *qnt_state,
			 int num_resp, int num_cell,
			 int memory, int rfield_shape,
			 int collision_flag);

%typemap(ruby,in) (int *state) {
  int i;
  int length;
  if (!rb_obj_is_kind_of($input,rb_cArray))
    rb_raise(rb_eArgError, "Expected Array of Integers");
  length = RARRAY($input)->len;
  $1 = malloc(length*sizeof(int));
  for (i=0; i<length; ++i)
    ($1)[i] = NUM2INT(RARRAY($input)->ptr[i]);
}
%typemap(freearg) (int *state) {
   if ($1) free($1);
}
%typemap(ruby,in) (int *respns) {
  int i;
  int length;
  if (!rb_obj_is_kind_of($input,rb_cArray))
    rb_raise(rb_eArgError, "Expected Array of Integers");
  length = RARRAY($input)->len;
  $1 = malloc(length*sizeof(int));
  for (i=0; i<length; ++i)
    ($1)[i] = NUM2INT(RARRAY($input)->ptr[i]);
}
%typemap(freearg) (int *respns) {
   if ($1) free($1);
}

%typemap(ruby,out) int {
  if($1 == 0) {
    $result = Qfalse;
  } else {
    $result = Qtrue;
  }
}

int train_cmac(int cmac_id, int *state, int *respns, int beta1, int beta2);

/* Need stuff here */

int cmac_response(int cmac_id, int *state, int *respns);


-Kurt


On Mon, 22 Nov 2004 13:09:03 -0600, Kurt Dresner <omega697@gmail.com> wrote:
> Here are the actual functions I need to wrap:
> 
> /* This one allocates a cmac, which is the thing I'm going to be
> using.  I tell it how many
>  * states it has, how many responses it has, and some other
> parameters.  The typemap you
>  * provided I think will work rather well for this function.
>  */
> int allocate_cmac(int num_state, int *qnt_state,
>                          int num_resp, int num_cell,
>                          int memory, int rfield_shape,
>                          int collision_flag);
> 
> /* With this function, I provide the ID of the cmac that was returned
> to me in the allocate
>  * function.  I then provide two arrays: the input states and the
> desired responses.  These
>  * have to be of the sizes num_state and num_resp from the last
> function.  I think a similar
>  * typemap will work just fine, since the C code presumably knows the
> size of the arrays.
>  * I just won't provide it.
>  */
> int train_cmac(int cmac_id, int *state, int *respns, int beta1, int beta2);
> 
> /* This is the one I'm stuck on.  I need to provide the ID, which will
> work, and then an array
>  * of state ints.  That will work too, as in the last one.  Now,
> however, I need to provide
>  * an array for the response.  This array is then filled up with the
> response.  Two things are
>  * confusing me.  I should probably do some sort of argout so I can
> get both the int
>  * (success/failure) return value (which I can probably map to
> true/nil right?) and the array
>  * return value.  The thing is, I don't know how to get it to create a
> Ruby array for this
>  * return value, since in the interface code, I don't know how big the
> array is.  The C code
>  * knows (presumably - I didn't write it).  So I don't know how to
> write the argout to take care
>  * of it.  I have no idea what to do with this.
>  */
> int cmac_response(int cmac_id, int *state, int *respns);
> 
> Any ideas?
> 
> -Kurt
> 
> 
> 
> 
> On Sun, 21 Nov 2004 22:58:07 +0900, Tobias Peters
> <tpeters@invalid.uni-oldenburg.de> wrote:
> > Kurt Dresner wrote:
> >
> >
> > > Hi all,
> > >
> > > I'm trying to get SWIG to create a wrapper for some C code.
> > > Specifically, there are several functions that take, as parameters, an
> > > int* (they also take the length of the array).  I don't know how to do
> > > the typemap for this - I want to be able to write
> > >
> > > My_module.my_c_function([1,2,3])
> > >
> > > for the corresponding C function
> > >
> > > void my_c_function(int size, int* ary)
> > >
> > > Additionally, one of the functions takes an integer array as a
> > > parameter, and I'd like it instead to return an array in Ruby (full of
> > > Nums).  I know how to get it to return the argument (instead of doing
> > > the pointer passing thing), but then it just thinks I want to pass it
> > > an integer instead of an array of integers.
> > >
> > > Anyone have any idea how to help me? Everything I've seen pertains to
> > > char** and I'm not sure how to convert it to work how I want with
> > > int*.
> >
> > Passing an array of integers from Ruby to C with SWIG requires
> > multi-argument "in" and "freearg" typemaps:
> >
> > %typemap(ruby,in) (int size, int *ary) {
> >    int i;
> >    if (!rb_obj_is_kind_of($input,rb_cArray))
> >      rb_raise(rb_eArgError, "Expected Array of Integers");
> >    $1 = RARRAY($input)->len;
> >    $2 = malloc($1*sizeof(int));
> >    for (i=0; i<$1; ++i)
> >      ($2)[i] = NUM2INT(RARRAY($input)->ptr[i]);
> > }
> > %typemap(freearg) (int size, int *ary) {
> >     if ($2) free($2);
> > }
> >
> > There's room for improvement in handling (or better: preventing)
> > exceptions raised from NUM2INT (proper error message and deallocation of
> > C array).
> >
> > Regarding output: It's not clear to me if you want in/out semantics or
> > output only. I think you can achieve in/out with an additional
> > multi-argument "argout" typemap. Output only implementation depends on
> > which function is responsible for allocating/freeing the array and which
> > is responsible for determining the array's size. You may need an
> > additional "arginit" typemap for this one.
> >
> >    Tobias
> >
> >
>