OpenSSL::PKey::EC::Group#point_conversion_form

static VALUE ossl_ec_group_get_point_conversion_form(VALUE self)
{
    EC_GROUP *group = NULL;
    point_conversion_form_t form;
    VALUE ret;

    GetECGroup(self, group);
    form = EC_GROUP_get_point_conversion_form(group);

    switch (form) {
    case POINT_CONVERSION_UNCOMPRESSED: ret = ID_uncompressed; break;
    case POINT_CONVERSION_COMPRESSED:   ret = ID_compressed; break;
    case POINT_CONVERSION_HYBRID:       ret = ID_hybrid; break;
    default:    ossl_raise(eEC_GROUP, "unsupported point conversion form: %d, this module should be updated", form);
    }

   return ID2SYM(ret);
}