Ruby » Ruby 1.8

static VALUE

fix_gcd(int argc, VALUE *argv, VALUE self) {

  if ( argc != 1 ) {

    rb_raise(rb_eArgError, "wrong number of arguments (%d for %d)", argc, 1);

  } else {

    /* Handle Fixnum#gcd(Fixnum) here. 

     * Note: Cannot handle values <= FIXNUM_MIN here due to overflow during negation.

     */

    long a, b;

    if ( FIXNUM_P(argv[0]) && (a = FIX2LONG(self)) > FIXNUM_MIN && (b = FIX2LONG(argv[0])) > FIXNUM_MIN ) {

      long min = a < 0 ? - a : a;

      long max = b < 0 ? - b : b;

      while ( min > 0 ) {

       long tmp = min;

       min = max % min;

       max = tmp;

      }

      return LONG2FIX(max);

    } else {

      /* Delegate to Integer#gcd. */

      return rb_call_super(1, argv);

    }

  }

}

    rb_define_method(rb_cFixnum, "gcd", fix_gcd, -1);