OpenSSL::BN.rand

static VALUE
ossl_bn_s_rand(int argc, VALUE *argv, VALUE klass)
{
    BIGNUM *result;
    int bottom = 0, top = 0, b;
    VALUE bits, fill, odd, obj;

    switch (rb_scan_args(argc, argv, "12", &bits, &fill, &odd)) {
      case 3:
        bottom = (odd == Qtrue) ? 1 : 0;
        /* FALLTHROUGH */
      case 2:
        top = NUM2INT(fill);
    }
    b = NUM2INT(bits);
    obj = NewBN(klass);
    if (!(result = BN_new())) {
        ossl_raise(eBNError, "BN_new");
    }
    if (BN_rand(result, b, top, bottom) <= 0) {
        BN_free(result);
        ossl_raise(eBNError, "BN_rand");
    }
    SetBN(obj, result);
    return obj;
}