From 05429b6cf5b3f30f773b8e79fe4cd3688349d7d2 Mon Sep 17 00:00:00 2001 From: AKASHI Takahiro Date: Wed, 13 Nov 2019 09:44:49 +0900 Subject: rtc: move date.c from drivers/rtc/ to lib/ In the next commit, rtc_mktime(), for compatibility with linux, will be implemented using rtc_mktime(), which is no longer drivers/rtc specific. So move this file under lib/. Signed-off-by: AKASHI Takahiro --- lib/date.c | 99 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 99 insertions(+) create mode 100644 lib/date.c (limited to 'lib/date.c') diff --git a/lib/date.c b/lib/date.c new file mode 100644 index 0000000000..63af4a1426 --- /dev/null +++ b/lib/date.c @@ -0,0 +1,99 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * (C) Copyright 2001 + * Wolfgang Denk, DENX Software Engineering, wd@denx.de. + */ + +#include +#include +#include +#include + +#if defined(CONFIG_LIB_DATE) || defined(CONFIG_TIMESTAMP) + +#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 int month_offset[] = { + 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) + */ +int rtc_calc_weekday(struct rtc_time *tm) +{ + int leaps_to_date; + int last_year; + int day; + + if (tm->tm_year < 1753) + return -1; + last_year = tm->tm_year - 1; + + /* Number of leap corrections to apply up to end of last year */ + leaps_to_date = last_year / 4 - last_year / 100 + last_year / 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 is. + */ + 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 += last_year * 365 + leaps_to_date + month_offset[tm->tm_mon - 1] + + tm->tm_mday; + tm->tm_wday = day % 7; + + return 0; +} + +/* + * 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 where 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 rtc_mktime(const struct rtc_time *tm) +{ + int mon = tm->tm_mon; + int year = tm->tm_year; + int days, hours; + + mon -= 2; + if (0 >= (int)mon) { /* 1..12 -> 11, 12, 1..10 */ + mon += 12; /* Puts Feb last since it has leap day */ + year -= 1; + } + + days = (unsigned long)(year / 4 - year / 100 + year / 400 + + 367 * mon / 12 + tm->tm_mday) + + year * 365 - 719499; + hours = days * 24 + tm->tm_hour; + return (hours * 60 + tm->tm_min) * 60 + tm->tm_sec; +} + +#endif /* CONFIG_LIB_DATE || CONFIG_TIMESTAMP */ -- cgit v1.2.3