/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2021 Justine Alexandra Roberts Tunney                              │
│                                                                              │
│ Permission to use, copy, modify, and/or distribute this software for         │
│ any purpose with or without fee is hereby granted, provided that the         │
│ above copyright notice and this permission notice appear in all copies.      │
│                                                                              │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
│ PERFORMANCE OF THIS SOFTWARE.                                                │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/internal.h"
#include "libc/fmt/conv.h"
#include "libc/nexgen32e/rdtsc.h"
#include "libc/nt/synchronization.h"
#include "libc/sysv/consts/clock.h"
#include "libc/sysv/errfuns.h"

textwindows int sys_clock_gettime_nt(int clockid, struct timespec *ts) {
  int64_t ms;
  struct timespec res;
  struct NtFileTime ft;
  static struct timespec mono;
  if (clockid == CLOCK_REALTIME) {
    GetSystemTimeAsFileTime(&ft);
    *ts = FileTimeToTimeSpec(ft);
    return 0;
  } else if (clockid == CLOCK_MONOTONIC || clockid == CLOCK_MONOTONIC_RAW) {
    ms = GetTickCount64();
    res.tv_sec = ms / 1000;
    res.tv_nsec = ms % 1000 * 1000000;
    res.tv_nsec += rdtsc() / 3 % 1000000000;
    if (res.tv_nsec > 1000000000) {
      res.tv_nsec -= 1000000000;
      res.tv_sec += 1;
    }
    if (res.tv_sec > mono.tv_sec ||
        (res.tv_sec == mono.tv_sec && res.tv_nsec > mono.tv_nsec)) {
      mono = res;
    } else {
      res = mono;
    }
    *ts = res;
    return 0;
  } else {
    return einval();
  }
}