/************************************************************
* gmtime_r.c
*
* Copyright (C) 2007 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* 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.
* 3. Neither the name Gregory Nutt nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
* COPYRIGHT OWNER 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.
*
************************************************************/
/************************************************************
* Included Files
************************************************************/
#include <sys/types.h>
#include <time.h>
#include <errno.h>
#include <debug.h>
#include "clock_internal.h"
/************************************************************
* Definitions
************************************************************/
/************************************************************
* Private Type Declarations
************************************************************/
/************************************************************
* Private Function Prototypes
************************************************************/
/* Calendar/UTC conversion routines */
static void clock_utc2calendar(time_t utc, int *year, int *month, int *day);
static void clock_utc2gregorian (time_t jdn, int *year, int *month, int *day);
#ifdef CONFIG_JULIAN_TIME
static void clock_utc2julian(time_t jdn, int *year, int *month, int *day);
#endif /* CONFIG_JULIAN_TIME */
/**********************************************************
* Public Constant Data
**********************************************************/
/************************************************************
* Public Variables
************************************************************/
/**********************************************************
* Private Variables
**********************************************************/
/************************************************************
* Private Functions
************************************************************/
/************************************************************
* Function: clock_calendar2utc, clock_gregorian2utc,
* and clock_julian2utc
*
* Description:
* Calendar to UTC conversion routines. These conversions
* are based on algorithms from p. 604 of Seidelman, P. K.
* 1992. Explanatory Supplement to the Astronomical
* Almanac. University Science Books, Mill Valley.
*
************************************************************/
static void clock_utc2calendar(time_t utc, int *year, int *month, int *day)
{
#ifdef CONFIG_JULIAN_TIME
if (utc >= GREG_DUTC)
{
clock_utc2gregorian(utc + JD_OF_EPOCH, year, month, day);
}
else
{
clock_utc2julian (utc + JD_OF_EPOCH, year, month, day);
}
#else /* CONFIG_JULIAN_TIME */
clock_utc2gregorian(utc + JD_OF_EPOCH, year, month, day);
#endif /* CONFIG_JULIAN_TIME */
}
static void clock_utc2gregorian(time_t jd, int *year, int *month, int *day)
{
long l, n, i, j, d, m, y;
l = jd + 68569;
n = (4*l) / 146097;
l = l - (146097*n + 3)/4;
i = (4000*(l+1))/1461001;
l = l - (1461*i)/4 + 31;
j = (80*l)/2447;
d = l - (2447*j)/80;
l = j/11;
m = j + 2 - 12*l;
y = 100*(n-49) + i + l;
*year = y;
*month = m;
*day = d;
}
#ifdef CONFIG_JULIAN_TIME
static void clock_utc2julian(time_t jd, int *year, int *month, int *day)
{
long j, k, l, n, d, i, m, y;
j = jd + 1402;
k = (j-1)/1461;
l = j - 1461*k;
n = (l-1)/365 - l/1461;
i = l - 365*n + 30;
j = (80*i)/2447;
d = i - (2447*j)/80;
i = j/11;
m = j + 2 - 12*i;
y = 4*k + n + i - 4716;
*year = y;
*month = m;
*day = d;
}
#endif /* CONFIG_JULIAN_TIME */
/************************************************************
* Public Functions
************************************************************/
/************************************************************
* Function: gmtime_r
*
* Description:
* Time conversion (based on the POSIX API)
*
************************************************************/
struct tm *gmtime_r(const time_t *clock, struct tm *result)
{
time_t time;
time_t jdn;
int year, month, day;
int hour, min, sec;
/* Get the seconds since the EPOCH */
time = *clock;
dbg("clock=%d\n", (int)time);
/* Convert to days, hours, minutes, and seconds since the EPOCH */
jdn = time / (24*60*60);
time -= (24*60*60) * jdn;
hour = time / (60*60);
time -= (60*60) * hour;
min = time / 60;
time -= 60 * min;
sec = time;
dbg("hour=%d min=%d sec=%d\n",
(int)hour, (int)min, (int)sec);
/* Convert the days since the EPOCH to calendar day */
clock_utc2calendar(jdn, &year, &month, &day);
dbg("jdn=%d year=%d month=%d day=%d\n",
(int)jdn, (int)year, (int)month, (int)day);
/* Then return the struct tm contents */
result->tm_year = (int)year - 1900;
result->tm_mon = (int)month - 1;
result->tm_mday = (int)day;
result->tm_hour = (int)hour;
result->tm_min = (int)min;
result->tm_sec = (int)sec;
return result;
}
