/************************************************************
* mktime.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 <debug.h>
#include "clock_internal.h"
/************************************************************
* Definitions
************************************************************/
/************************************************************
* Private Type Declarations
************************************************************/
/************************************************************
* Private Function Prototypes
************************************************************/
/**********************************************************
* Public Constant Data
**********************************************************/
/************************************************************
* Public Variables
************************************************************/
/**********************************************************
* Private Variables
**********************************************************/
/************************************************************
* Private Functions
************************************************************/
/************************************************************
* Function: clock_gregorian2utc, clock_julian2utc
*
* Description:
* 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 time_t clock_gregorian2utc(int year, int month, int day)
{
int temp;
/* temp = (month - 14)/12; */
temp = (month <= 2 ? -1:0);
return (1461*(year + 4800 + temp))/4
+ (367*(month - 2 - 12*temp))/12
- (3*((year + 4900 + temp)/100))/4 + day - 32075;
}
#ifdef CONFIG_JULIAN_TIME
static time_t clock_julian2utc(int year, int month, int day)
{
return 367*year
- (7*(year + 5001 + (month-9)/7))/4
+ (275*month)/9
+ day + 1729777;
}
#endif
/************************************************************
* Public Functions
************************************************************/
/************************************************************
* Function: mktime
*
* Description:
* Time conversion (based on the POSIX API)
*
************************************************************/
time_t mktime(struct tm *tp)
{
time_t ret;
time_t jdn;
/* Get the EPOCH-relative julian date from the calendar year,
* month, and date
*/
jdn = clock_calendar2utc(tp->tm_year+1900, tp->tm_mon+1, tp->tm_mday);
dbg("jdn=%d tm_year=%d tm_mon=%d tm_mday=%d\n",
(int)jdn, tp->tm_year, tp->tm_mon, tp->tm_mday);
/* Return the seconds into the julian day. */
ret = ((jdn*24 + tp->tm_hour)*60 + tp->tm_min)*60 + tp->tm_sec;
dbg("%s:\tret=%d tm_hour=%d tm_min=%d tm_sec=%d\n",
(int)ret, tp->tm_hour, tp->tm_min, tp->tm_sec);
return ret;
}
/************************************************************
* Function: clock_calendar2utc
*
* Description:
* Calendar/UTC conversion based on algorithms from p. 604
* of Seidelman, P. K. 1992. Explanatory Supplement to
* the Astronomical Almanac. University Science Books,
* Mill Valley.
*
************************************************************/
time_t clock_calendar2utc(int year, int month, int day)
{
int dyear;
#ifdef CONFIG_JULIAN_TIME
int isgreg;
#endif /* CONFIG_JULIAN_TIME */
/* Correct year & month ranges. Shift month into range 1-12 */
dyear = (month-1) / 12;
month -= 12 * dyear;
year += dyear;
if (month < 1)
{
month += 12;
year -= 1;
}
#ifdef CONFIG_JULIAN_TIME
/* Determine which calendar to use */
if (year > GREG_YEAR)
{
isgreg = TRUE;
}
else if (year < GREG_YEAR)
{
isgreg = FALSE;
}
else if (month > GREG_MONTH)
{
isgreg = TRUE;
}
else if (month < GREG_MONTH)
{
isgreg = FALSE;
}
else
{
isgreg = (day >= GREG_DAY);
}
/* Calculate and return date */
if (isgreg)
{
return clock_gregorian2utc(year, month, day) - JD_OF_EPOCH;
}
else
{
return clock_julian2utc (year, month, day) - JD_OF_EPOCH;
}
#else /* CONFIG_JULIAN_TIME */
return clock_gregorian2utc(year, month, day) - JD_OF_EPOCH;
#endif /* CONFIG_JULIAN_TIME */
}
