diff options
Diffstat (limited to 'sys/kern')
| -rw-r--r-- | sys/kern/clock_subr.c | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/sys/kern/clock_subr.c b/sys/kern/clock_subr.c new file mode 100644 index 00000000000..b661121c6af --- /dev/null +++ b/sys/kern/clock_subr.c @@ -0,0 +1,158 @@ +/* $OpenBSD: clock_subr.c,v 1.1 2006/06/19 15:13:35 deraadt Exp $ */ +/* $NetBSD: clock_subr.c,v 1.3 1997/03/15 18:11:16 is Exp $ */ + +/* + * Copyright (c) 1988 University of Utah. + * Copyright (c) 1982, 1990, 1993 + * The Regents of the University of California. All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * the Systems Programming Group of the University of Utah Computer + * Science Department. + * + * 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 of the University 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 REGENTS 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 REGENTS 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. + * + * from: Utah $Hdr: clock.c 1.18 91/01/21$ + * + * @(#)clock.c 8.2 (Berkeley) 1/12/94 + */ + +/* + * Generic routines to convert between a POSIX date + * (seconds since 1/1/1970) and yr/mo/day/hr/min/sec + * Derived from arch/hp300/hp300/clock.c + */ + +#include <sys/types.h> +#include <sys/systm.h> + +#include <dev/clock_subr.h> + +static inline int leapyear(int year); +#define FEBRUARY 2 +#define days_in_year(a) (leapyear(a) ? 366 : 365) +#define days_in_month(a) (month_days[(a) - 1]) + +static const int month_days[12] = { + 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 +}; + +/* + * This inline avoids some unnecessary modulo operations + * as compared with the usual macro: + * ( ((year % 4) == 0 && + * (year % 100) != 0) || + * ((year % 400) == 0) ) + * It is otherwise equivalent. + */ +static inline int +leapyear(int year) +{ + int rv = 0; + + if ((year & 3) == 0) { + rv = 1; + if ((year % 100) == 0) { + rv = 0; + if ((year % 400) == 0) + rv = 1; + } + } + return (rv); +} + +time_t +clock_ymdhms_to_secs(struct clock_ymdhms *dt) +{ + time_t secs; + int i, year, days; + + year = dt->dt_year; + + /* + * Compute days since start of time + * First from years, then from months. + */ + days = 0; + for (i = POSIX_BASE_YEAR; i < year; i++) + days += days_in_year(i); + if (leapyear(year) && dt->dt_mon > FEBRUARY) + days++; + + /* Months */ + for (i = 1; i < dt->dt_mon; i++) + days += days_in_month(i); + days += (dt->dt_day - 1); + + /* Add hours, minutes, seconds. */ + secs = ((days + * 24 + dt->dt_hour) + * 60 + dt->dt_min) + * 60 + dt->dt_sec; + + return (secs); +} + +/* This function uses a copy of month_days[] */ +#undef days_in_month +#define days_in_month(a) (mthdays[(a) - 1]) + +void +clock_secs_to_ymdhms(time_t secs, struct clock_ymdhms *dt) +{ + int mthdays[12]; + int i, days; + int rsec; /* remainder seconds */ + + bcopy(month_days, mthdays, sizeof(mthdays)); + + days = secs / SECDAY; + rsec = secs % SECDAY; + + /* Day of week (Note: 1/1/1970 was a Thursday) */ + dt->dt_wday = (days + 4) % 7; + + /* Subtract out whole years, counting them in i. */ + for (i = POSIX_BASE_YEAR; days >= days_in_year(i); i++) + days -= days_in_year(i); + dt->dt_year = i; + + /* Subtract out whole months, counting them in i. */ + if (leapyear(i)) + days_in_month(FEBRUARY) = 29; + for (i = 1; days >= days_in_month(i); i++) + days -= days_in_month(i); + dt->dt_mon = i; + + /* Days are what is left over (+1) from all that. */ + dt->dt_day = days + 1; + + /* Hours, minutes, seconds are easy */ + dt->dt_hour = rsec / 3600; + rsec = rsec % 3600; + dt->dt_min = rsec / 60; + rsec = rsec % 60; + dt->dt_sec = rsec; +} |