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Diffstat (limited to 'nuttx/lib/time/lib_calendar2utc.c')
-rw-r--r-- | nuttx/lib/time/lib_calendar2utc.c | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/nuttx/lib/time/lib_calendar2utc.c b/nuttx/lib/time/lib_calendar2utc.c new file mode 100644 index 000000000..642e23568 --- /dev/null +++ b/nuttx/lib/time/lib_calendar2utc.c @@ -0,0 +1,209 @@ +/**************************************************************************** + * 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 */ + |