srecord VNStatData(
  S lastMonthTotal,
  S thisMonthTotal, S thisMonthEstimated,
  S yesterdayTotal,
  S todayTotal, S todayEstimated
) {}

static VNStatData parse_vnstat(S output) {
  LS lines = lines(output);
  new VNStatData data;
  
  int i = indexOfContaining(lines, "monthly");
  if (i >= 0) {
    i = indexOfContaining(lines, i, "---")+1;
    i = indexOfContaining(lines, i, "---")+1;
    LS lastMonth = splitAtVerticalBar(get(lines, i-3));
    LS thisMonth = splitAtVerticalBar(get(lines, i-2));
    LS estimated = splitAtVerticalBar(get(lines, i));
    data.lastMonthTotal = get(lastMonth, 2);
    data.thisMonthTotal = get(thisMonth, 2);
    data.thisMonthEstimated = get(estimated, 2);
  }
  
  i = indexOfContaining(lines, "daily");
  if (i >= 0) {
    i = indexOfContaining(lines, i, "---")+1;
    i = indexOfContaining(lines, i, "---")+1;
    LS yesterday = splitAtVerticalBar(get(lines, i-3));
    LS today = splitAtVerticalBar(get(lines, i-2));
    LS estimated = splitAtVerticalBar(get(lines, i));
    data.yesterdayTotal = get(yesterday, 2);
    data.todayTotal = get(today, 2);
    data.todayEstimated = get(estimated, 2);
  }
  
  ret data;
}