[z180-stamp.git] / avr / date.c

/*
 * (C) Copyright 2001
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

/*
 * Date & Time support for RTC
 */

#include <common.h>
#include <command.h>
#include <rtc.h>


#define FEBRUARY		2
#define	STARTOFTIME		1970
#define SECDAY			86400L
#define SECYR			(SECDAY * 365)
#define	leapyear(year)		((year) % 4 == 0)
#define	days_in_year(a)		(leapyear(a) ? 366 : 365)
#define	days_in_month(a)	(month_days[(a) - 1])


static const FLASH int MonthOffset[] = {
	0,31,59,90,120,151,181,212,243,273,304,334
};

/*
 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK)
 */
void GregorianDay(struct rtc_time * tm)
{
	int leapsToDate;
	int lastYear;
	int day;

	lastYear=tm->tm_year-1;

	/*
	 * Number of leap corrections to apply up to end of last year
	 */
	leapsToDate = lastYear/4 - lastYear/100 + lastYear/400;

	/*
	 * This year is a leap year if it is divisible by 4 except when it is
	 * divisible by 100 unless it is divisible by 400
	 *
	 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 will be
	 */
	if((tm->tm_year%4==0) &&
	   ((tm->tm_year%100!=0) || (tm->tm_year%400==0)) &&
	   (tm->tm_mon>2)) {
		/*
		 * We are past Feb. 29 in a leap year
		 */
		day=1;
	} else {
		day=0;
	}

	day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] + tm->tm_mday;

	tm->tm_wday=day%7;
}

void to_tm(unsigned long tim, struct rtc_time * tm)
{
	char month_days[12] = {31,28,31,30,31,30,31,31,30,31,30,31};
	register int    i;
	register long   hms, day;

	day = tim / SECDAY;
	hms = tim % SECDAY;

	/* Hours, minutes, seconds are easy */
	tm->tm_hour = hms / 3600;
	tm->tm_min = (hms % 3600) / 60;
	tm->tm_sec = (hms % 3600) % 60;

	/* Number of years in days */
	for (i = STARTOFTIME; day >= days_in_year(i); i++) {
		day -= days_in_year(i);
	}
	tm->tm_year = i;

	/* Number of months in days left */
	if (leapyear(tm->tm_year)) {
		days_in_month(FEBRUARY) = 29;
	}
	for (i = 1; day >= days_in_month(i); i++) {
		day -= days_in_month(i);
	}
	days_in_month(FEBRUARY) = 28;
	tm->tm_mon = i;

	/* Days are what is left over (+1) from all that. */
	tm->tm_mday = day + 1;

	/*
	 * Determine the day of week
	 */
	GregorianDay(tm);
}

/* Converts Gregorian date to seconds since 1970-01-01 00:00:00.
 * Assumes input in normal date format, i.e. 1980-12-31 23:59:59
 * => year=1980, mon=12, day=31, hour=23, min=59, sec=59.
 *
 * [For the Julian calendar (which was used in Russia before 1917,
 * Britain & colonies before 1752, anywhere else before 1582,
 * and is still in use by some communities) leave out the
 * -year/100+year/400 terms, and add 10.]
 *
 * This algorithm was first published by Gauss (I think).
 *
 * WARNING: this function will overflow on 2106-02-07 06:28:16 on
 * machines were long is 32-bit! (However, as time_t is signed, we
 * will already get problems at other places on 2038-01-19 03:14:08)
 */
unsigned long
mktime (unsigned int year, unsigned int mon,
	unsigned int day, unsigned int hour,
	unsigned int min, unsigned int sec)
{
	if (0 >= (int) (mon -= 2)) {	/* 1..12 -> 11,12,1..10 */
		mon += 12;		/* Puts Feb last since it has leap day */
		year -= 1;
	}

	return (((
		(unsigned long) (year/4 - year/100 + year/400 + 367*mon/12 + day) +
			year*365 - 719499
	    )*24 + hour /* now have hours */
	  )*60 + min /* now have minutes */
	)*60 + sec; /* finally seconds */
}
Commit	Line	Data
61b0cfe9 L	1	/*
	2	* (C) Copyright 2001
	3	* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
	4	*
	5	* SPDX-License-Identifier: GPL-2.0+
	6	*/
	7
	8	/*
	9	* Date & Time support for RTC
	10	*/
	11
	12	#include <common.h>
	13	#include <command.h>
	14	#include <rtc.h>
	15
	16
	17	#define FEBRUARY 2
	18	#define STARTOFTIME 1970
	19	#define SECDAY 86400L
	20	#define SECYR (SECDAY * 365)
	21	#define leapyear(year) ((year) % 4 == 0)
	22	#define days_in_year(a) (leapyear(a) ? 366 : 365)
	23	#define days_in_month(a) (month_days[(a) - 1])
	24
	25
c93a1fd4	26	static const FLASH int MonthOffset[] = {
61b0cfe9 L	27	0,31,59,90,120,151,181,212,243,273,304,334
	28	};
	29
	30	/*
	31	* This only works for the Gregorian calendar - i.e. after 1752 (in the UK)
	32	*/
	33	void GregorianDay(struct rtc_time * tm)
	34	{
	35	int leapsToDate;
	36	int lastYear;
	37	int day;
	38
	39	lastYear=tm->tm_year-1;
	40
	41	/*
	42	* Number of leap corrections to apply up to end of last year
	43	*/
	44	leapsToDate = lastYear/4 - lastYear/100 + lastYear/400;
	45
	46	/*
	47	* This year is a leap year if it is divisible by 4 except when it is
	48	* divisible by 100 unless it is divisible by 400
	49	*
	50	* e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 will be
	51	*/
	52	if((tm->tm_year%4==0) &&
	53	((tm->tm_year%100!=0) \|\| (tm->tm_year%400==0)) &&
	54	(tm->tm_mon>2)) {
	55	/*
	56	* We are past Feb. 29 in a leap year
	57	*/
	58	day=1;
	59	} else {
	60	day=0;
	61	}
	62
	63	day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] + tm->tm_mday;
	64
	65	tm->tm_wday=day%7;
	66	}
	67
	68	void to_tm(unsigned long tim, struct rtc_time * tm)
	69	{
	70	char month_days[12] = {31,28,31,30,31,30,31,31,30,31,30,31};
	71	register int i;
	72	register long hms, day;
	73
	74	day = tim / SECDAY;
	75	hms = tim % SECDAY;
	76
	77	/* Hours, minutes, seconds are easy */
	78	tm->tm_hour = hms / 3600;
	79	tm->tm_min = (hms % 3600) / 60;
	80	tm->tm_sec = (hms % 3600) % 60;
	81
	82	/* Number of years in days */
	83	for (i = STARTOFTIME; day >= days_in_year(i); i++) {
	84	day -= days_in_year(i);
	85	}
	86	tm->tm_year = i;
	87
	88	/* Number of months in days left */
	89	if (leapyear(tm->tm_year)) {
	90	days_in_month(FEBRUARY) = 29;
91	}
92	for (i = 1; day >= days_in_month(i); i++) {
93	day -= days_in_month(i);
94	}
95	days_in_month(FEBRUARY) = 28;
96	tm->tm_mon = i;
97
98	/* Days are what is left over (+1) from all that. */
99	tm->tm_mday = day + 1;
100
101	/*
102	* Determine the day of week
103	*/
104	GregorianDay(tm);
105	}
106
107	/* Converts Gregorian date to seconds since 1970-01-01 00:00:00.
108	* Assumes input in normal date format, i.e. 1980-12-31 23:59:59
109	* => year=1980, mon=12, day=31, hour=23, min=59, sec=59.
110	*
111	* [For the Julian calendar (which was used in Russia before 1917,
112	* Britain & colonies before 1752, anywhere else before 1582,
113	* and is still in use by some communities) leave out the
114	* -year/100+year/400 terms, and add 10.]
115	*
116	* This algorithm was first published by Gauss (I think).
117	*
118	* WARNING: this function will overflow on 2106-02-07 06:28:16 on
119	* machines were long is 32-bit! (However, as time_t is signed, we
120	* will already get problems at other places on 2038-01-19 03:14:08)
121	*/
122	unsigned long
123	mktime (unsigned int year, unsigned int mon,
124	unsigned int day, unsigned int hour,
125	unsigned int min, unsigned int sec)
126	{
127	if (0 >= (int) (mon -= 2)) { /* 1..12 -> 11,12,1..10 */
128	mon += 12; /* Puts Feb last since it has leap day */
129	year -= 1;
130	}
131
132	return (((
133	(unsigned long) (year/4 - year/100 + year/400 + 367*mon/12 + day) +
134	year*365 - 719499
135	)24 + hour / now have hours */
136	)60 + min / now have minutes */
137	)60 + sec; / finally seconds */
138	}