cdf_time.c

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/*-
 * 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