From bd6805a8c18f859a8f467965f2ee780817d8a81e Mon Sep 17 00:00:00 2001 From: Michael Brown Date: Mon, 19 Mar 2012 16:09:41 +0000 Subject: [PATCH] [libc] Add mktime() function Signed-off-by: Michael Brown --- src/core/time.c | 137 +++++++++++++++++++++++++++++++++++++++++ src/include/sys/time.h | 24 ++++---- src/include/time.h | 37 +++++++---- 3 files changed, 173 insertions(+), 25 deletions(-) create mode 100644 src/core/time.c diff --git a/src/core/time.c b/src/core/time.c new file mode 100644 index 00000000..52ae3ee9 --- /dev/null +++ b/src/core/time.c @@ -0,0 +1,137 @@ +/* + * Copyright (C) 2012 Michael Brown . + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of the + * License, or any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +FILE_LICENCE ( GPL2_OR_LATER ); + +#include + +/** @file + * + * Date and time + * + * POSIX:2008 section 4.15 defines "seconds since the Epoch" as an + * abstract measure approximating the number of seconds that have + * elapsed since the Epoch, excluding leap seconds. The formula given + * is + * + * tm_sec + tm_min*60 + tm_hour*3600 + tm_yday*86400 + + * (tm_year-70)*31536000 + ((tm_year-69)/4)*86400 - + * ((tm_year-1)/100)*86400 + ((tm_year+299)/400)*86400 + * + * This calculation assumes that leap years occur in each year that is + * either divisible by 4 but not divisible by 100, or is divisible by + * 400. + */ + +/** Days of week (for debugging) */ +static const char *weekdays[] = { + "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" +}; + +/** + * Determine whether or not year is a leap year + * + * @v tm_year Years since 1900 + * @v is_leap_year Year is a leap year + */ +static int is_leap_year ( int tm_year ) { + int leap_year = 0; + + if ( ( tm_year % 4 ) == 0 ) + leap_year = 1; + if ( ( tm_year % 100 ) == 0 ) + leap_year = 0; + if ( ( tm_year % 400 ) == 100 ) + leap_year = 1; + + return leap_year; +} + +/** + * Calculate number of leap years since 1900 + * + * @v tm_year Years since 1900 + * @v num_leap_years Number of leap years + */ +static int leap_years_to_end ( int tm_year ) { + int leap_years = 0; + + leap_years += ( tm_year / 4 ); + leap_years -= ( tm_year / 100 ); + leap_years += ( ( tm_year + 300 ) / 400 ); + + return leap_years; +} + +/** + * Calculate day of week + * + * @v tm_year Years since 1900 + * @v tm_mon Month of year [0,11] + * @v tm_day Day of month [1,31] + */ +static int day_of_week ( int tm_year, int tm_mon, int tm_mday ) { + static const uint8_t offset[12] = + { 1, 4, 3, 6, 1, 4, 6, 2, 5, 0, 3, 5 }; + int pseudo_year = tm_year; + + if ( tm_mon < 2 ) + pseudo_year--; + return ( ( pseudo_year + leap_years_to_end ( pseudo_year ) + + offset[tm_mon] + tm_mday ) % 7 ); +} + +/** Days from start of year until start of months (in non-leap years) */ +static const uint16_t days_to_month_start[] = + { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 }; + +/** + * Calculate seconds since the Epoch + * + * @v tm Broken-down time + * @ret time Seconds since the Epoch + */ +time_t mktime ( struct tm *tm ) { + int days_since_epoch; + int seconds_since_day; + time_t seconds; + + /* Calculate day of year */ + tm->tm_yday = ( ( tm->tm_mday - 1 ) + + days_to_month_start[ tm->tm_mon ] ); + if ( ( tm->tm_mon >= 2 ) && is_leap_year ( tm->tm_year ) ) + tm->tm_yday++; + + /* Calculate day of week */ + tm->tm_wday = day_of_week ( tm->tm_year, tm->tm_mon, tm->tm_mday ); + + /* Calculate seconds since the Epoch */ + days_since_epoch = ( tm->tm_yday + ( 365 * tm->tm_year ) - 25567 + + leap_years_to_end ( tm->tm_year - 1 ) ); + seconds_since_day = + ( ( ( ( tm->tm_hour * 60 ) + tm->tm_min ) * 60 ) + tm->tm_sec ); + seconds = ( ( ( ( time_t ) days_since_epoch ) * ( ( time_t ) 86400 ) ) + + seconds_since_day ); + + DBGC ( &weekdays, "TIME %04d-%02d-%02d %02d:%02d:%02d => %lld (%s, " + "day %d)\n", ( tm->tm_year + 1900 ), ( tm->tm_mon + 1 ), + tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec, seconds, + weekdays[ tm->tm_wday ], tm->tm_yday ); + + return seconds; +} diff --git a/src/include/sys/time.h b/src/include/sys/time.h index 21fb7e99..6c9b7421 100644 --- a/src/include/sys/time.h +++ b/src/include/sys/time.h @@ -1,20 +1,18 @@ #ifndef _SYS_TIME_H #define _SYS_TIME_H -#include +/** @file + * + * Date and time + */ -typedef unsigned long suseconds_t; +#include -struct timeval { - time_t tv_sec; /* seconds */ - suseconds_t tv_usec; /* microseconds */ -}; - -struct timezone { - int tz_minuteswest; /* minutes W of Greenwich */ - int tz_dsttime; /* type of dst correction */ -}; - -extern int gettimeofday ( struct timeval *tv, struct timezone *tz ); +/** Seconds since the Epoch + * + * We use a 64-bit type to avoid Y2K38 issues, since we may have to + * handle distant future dates (e.g. X.509 certificate expiry dates). + */ +typedef int64_t time_t; #endif /* _SYS_TIME_H */ diff --git a/src/include/time.h b/src/include/time.h index 6ea927c3..f33300ab 100644 --- a/src/include/time.h +++ b/src/include/time.h @@ -1,22 +1,35 @@ #ifndef _TIME_H #define _TIME_H -typedef unsigned long time_t; +/** @file + * + * Date and time + */ +#include + +/** Broken-down time */ struct tm { - int tm_sec; /* seconds */ - int tm_min; /* minutes */ - int tm_hour; /* hours */ - int tm_mday; /* day of the month */ - int tm_mon; /* month */ - int tm_year; /* year */ - int tm_wday; /* day of the week */ - int tm_yday; /* day in the year */ - int tm_isdst; /* daylight saving time */ + /** Seconds [0,60] */ + int tm_sec; + /** Minutes [0,59] */ + int tm_min; + /** Hour [0,23] */ + int tm_hour; + /** Day of month [1,31] */ + int tm_mday; + /** Month of year [0,11] */ + int tm_mon; + /** Years since 1900 */ + int tm_year; + /** Day of week [0,6] (Sunday=0) */ + int tm_wday; + /** Day of year [0,365] */ + int tm_yday; + /** Daylight savings flag */ + int tm_isdst; }; -extern time_t time ( time_t *t ); - extern time_t mktime ( struct tm *tm ); #endif /* _TIME_H */