/**************************************************************************** * libc/time/lib_calendar2utc.c * * Copyright (C) 2007, 2009, 2011 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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 #include #include #include #include /**************************************************************************** * 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) { time_t days; /* Years since epoch in units of days (ignoring leap years). */ days = (year - 1970) * 365; /* Add in the extra days for the leap years prior to the current year. */ days += (year - 1969) >> 2; /* Add in the days up to the beginning of this month. */ days += (time_t)clock_daysbeforemonth(month, clock_isleapyear(year)); /* Add in the days since the beginning of this month (days are 1-based). */ days += day - 1; /* Then convert the seconds and add in hours, minutes, and seconds */ return days; } #endif /* CONFIG_GREGORIAN_TIME */