/*-

 * Copyright (c) 2008 Christos Zoulas

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS

 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED

 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS

 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

 * POSSIBILITY OF SUCH DAMAGE.

 */

#include "file.h"

#ifndef lint

FILE_RCSID("@(#)$File: cdf_time.c,v 1.24 2023/07/17 15:54:44 christos Exp $")

#endif

#include <time.h>

#ifdef TEST

#include <err.h>

#endif

#include <string.h>

#include "cdf.h"

#define isleap(y) ((((y) % 4) == 0) && \

    ((((y) % 100) != 0) || (((y) % 400) == 0)))

static const int mdays[] = {

    31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31

};

/*

 * Return the number of days between jan 01 1601 and jan 01 of year.

 */

static int

cdf_getdays(int year)

{

  int days = 0;

  int y;

  for (y = CDF_BASE_YEAR; y < year; y++)

    days += isleap(y) + 365;

  return days;

}

/*

 * Return the day within the month

 */

static int

cdf_getday(int year, int days)

{

  size_t m;

  for (m = 0; m < __arraycount(mdays); m++) {

    int sub = mdays[m] + (m == 1 && isleap(year));

    if (days < sub)

      return days;

    days -= sub;

  }

  return days;

}

/*

 * Return the 0...11 month number.

 */

static int

cdf_getmonth(int year, int days)

{

  size_t m;

  for (m = 0; m < __arraycount(mdays); m++) {

    days -= mdays[m];

    if (m == 1 && isleap(year))

      days--;

    if (days <= 0)

      return CAST(int, m);

  }

  return CAST(int, m);

}

int

cdf_timestamp_to_timespec(struct timespec *ts, cdf_timestamp_t t)

{

  struct tm tm;

#ifdef HAVE_STRUCT_TM_TM_ZONE

  static char UTC[] = "UTC";

#endif

  int rdays;

  /* Unit is 100's of nanoseconds */

  ts->tv_nsec = (t % CDF_TIME_PREC) * 100;

  t /= CDF_TIME_PREC;

  tm.tm_sec = CAST(int, t % 60);

  t /= 60;

  tm.tm_min = CAST(int, t % 60);

  t /= 60;

  tm.tm_hour = CAST(int, t % 24);

  t /= 24;

  /* XXX: Approx */

  tm.tm_year = CAST(int, CDF_BASE_YEAR + (t / 365));

  rdays = cdf_getdays(tm.tm_year);

  t -= rdays - 1;

  tm.tm_mday = cdf_getday(tm.tm_year, CAST(int, t));

  tm.tm_mon = cdf_getmonth(tm.tm_year, CAST(int, t));

  tm.tm_wday = 0;

  tm.tm_yday = 0;

  tm.tm_isdst = 0;

#ifdef HAVE_STRUCT_TM_TM_GMTOFF

  tm.tm_gmtoff = 0;

#endif

#ifdef HAVE_STRUCT_TM_TM_ZONE

  tm.tm_zone = UTC;

#endif

  tm.tm_year -= 1900;

  ts->tv_sec = mktime(&tm);

  if (ts->tv_sec == -1) {

    errno = EINVAL;

    return -1;

  }

  return 0;

}

int

/*ARGSUSED*/

cdf_timespec_to_timestamp(cdf_timestamp_t *t, const struct timespec *ts)

{

#ifndef __lint__

  (void)&t;

  (void)&ts;

#endif

#ifdef notyet

  struct tm tm;

  if (gmtime_r(&ts->ts_sec, &tm) == NULL) {

    errno = EINVAL;

    return -1;

  }

  *t = (ts->ts_nsec / 100) * CDF_TIME_PREC;

  *t += tm.tm_sec;

  *t += tm.tm_min * 60;

  *t += tm.tm_hour * 60 * 60;

  *t += tm.tm_mday * 60 * 60 * 24;

#endif

  return 0;

}

char *

cdf_ctime(const time_t *sec, char *buf)

{

  char *ptr = *sec > MAX_CTIME ? NULL : ctime_r(sec, buf);

  if (ptr != NULL)

    return buf;

#ifdef WIN32

  (void)snprintf(buf, 26, "*Bad* 0x%16.16I64x\n",

      CAST(long long, *sec));

#else

  (void)snprintf(buf, 26, "*Bad* %#16.16" INT64_T_FORMAT "x\n",

      CAST(long long, *sec));

#endif

  return buf;

}

#ifdef TEST_TIME

int

main(int argc, char *argv[])

{

  struct timespec ts;

  char buf[25];

  static const cdf_timestamp_t tst = 0x01A5E403C2D59C00ULL;

  static const char *ref = "Sat Apr 23 01:30:00 1977";

  char *p, *q;

  cdf_timestamp_to_timespec(&ts, tst);

  p = cdf_ctime(&ts.tv_sec, buf);

  if ((q = strchr(p, '\n')) != NULL)

    *q = '\0';

  if (strcmp(ref, p) != 0)

    errx(1, "Error date %s != %s\n", ref, p);

  return 0;

}

#endif