static VALUE rhrd_asctime(VALUE self) {
  VALUE s;
  rhrd_t *d;
  int len;
  Data_Get_Struct(self, rhrd_t, d);
  RHR_FILL_CIVIL(d)
  RHR_FILL_JD(d)

  s = rb_str_buf_new(128);
  len = snprintf(RSTRING_PTR(s), 128, "%s %s %2hhi 00:00:00 %04li", 
        rhrd__abbr_day_names[rhrd__jd_to_wday(d->jd)],
        rhrd__abbr_month_names[d->month],
        d->day,
        d->year);
  if (len == -1 || len > 127) {
    rb_raise(rb_eNoMemError, "in Date#asctime (in snprintf)");
  }

  rb_str_set_len(s, len);
  return s;
}