From: Kouhei Sutou <kou@...>
Date: 2006-11-15T21:40:52+09:00
Subject: Re: Ruby <-SWIG-> C arrays

Hi,

In <2250e499a84aaf577be46b5e5ffd238a@ruby-forum.com>
  "Ruby <-SWIG-> C arrays" on Wed, 15 Nov 2006 02:04:14 +0900,
  Aureliano Buendia <saveez@hotmail.com> wrote:

> 
> typedef unsigned long uInt32
> someFunction(uInt32 someArray[])
> 
> The array is simply some input. Calling the wrapped function in Ruby:
> 
> Wrapper.someFunction([1, 2, 3])
> 
> produces this error:

Here is a my answer:

  %module "Example";

  %inline %{
  typedef unsigned long uInt32;
  %}

  %typemap(in, numinputs=1) (uInt32 some_array[], int length)
  {
    int i;

    $2 = RARRAY($input)->len;
    $1 = ALLOCA_N(uInt32, $2);

    for (i = 0; i < $2; i++) {
      $1[i] = NUM2INT(RARRAY($input)->ptr[i]);
    }
  };


  %inline %{
  uInt32
  some_function(uInt32 some_array[], int length) {
    int i;
    uInt32 sum = 0;
    for (i = 0; i < length; i++) {
      sum += some_array[i];
    }
    return sum;
  }
  %}


Compile:
  % swig -ruby a.i && ruby -r mkmf -e 'create_makefile("Example")' && make

Test:
  % ruby -r Example -e 'p Example.some_function([1, 2, 3])'
  6


Thanks,
--
kou