/****************************************************************************
* lib/time/lib_calendar2utc.c
*
* Copyright (C) 2007, 2009, 2011 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 NuttX 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 <nuttx/config.h>
#include <stdbool.h>
#include <time.h>
#include <debug.h>
#include <nuttx/time.h>
/****************************************************************************
* Pre-processor 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.
*
****************************************************************************/
#ifdef CONFIG_GREGORIAN_TIME
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 /* CONFIG_JULIAN_TIME */
#endif /* CONFIG_GREGORIAN_TIME */
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* 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.
*
****************************************************************************/
#ifdef CONFIG_GREGORIAN_TIME
time_t clock_calendar2utc(int year, int month, int day)
{
int dyear;
#ifdef CONFIG_JULIAN_TIME
bool 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 */
}
#else
/* A highly simplified version that only handles days in the time
* since Jan 1, 1970.
*/
time_t clock_calendar2utc(int year, int month, int day)
{
struct tm t;
/* mktime can (kind of) do this */
t.tm_year = year;
t.tm_mon = month;
t.tm_mday = day;
t.tm_hour = 0;
t.tm_min = 0;
t.tm_sec = 0;
return mktime(&t);
}
#endif /* CONFIG_GREGORIAN_TIME */
