f7afe7679c
that start in 1970, assume most conversions are going to be for recent dates and use a precomputed number of days through the end of 2016. This is a do-over of r320997, hopefully this time with 100% more workiness. The first attempt had an off-by-one error, but instead of just adding another mysterious +1 adjustment, this rearranges the relationship between recent_base_year and recent_base_days so that the latter is the number of days that occurred before the start of the associated year (instead of the count thru the end of that year). This makes the recent_base stuff work more like the original loop logic that didn't need any +1 adjustments.
258 lines
7.2 KiB
C
258 lines
7.2 KiB
C
/*-
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* Copyright (c) 1988 University of Utah.
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* Copyright (c) 1982, 1990, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* the Systems Programming Group of the University of Utah Computer
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* Science Department.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from: Utah $Hdr: clock.c 1.18 91/01/21$
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* from: @(#)clock.c 8.2 (Berkeley) 1/12/94
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* from: NetBSD: clock_subr.c,v 1.6 2001/07/07 17:04:02 thorpej Exp
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* and
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* from: src/sys/i386/isa/clock.c,v 1.176 2001/09/04
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/bus.h>
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#include <sys/clock.h>
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#include <sys/limits.h>
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#include <sys/sysctl.h>
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#include <sys/timetc.h>
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int tz_minuteswest;
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int tz_dsttime;
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/*
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* The adjkerntz and wall_cmos_clock sysctls are in the "machdep" sysctl
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* namespace because they were misplaced there originally.
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*/
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static int adjkerntz;
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static int
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sysctl_machdep_adjkerntz(SYSCTL_HANDLER_ARGS)
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{
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int error;
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error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req);
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if (!error && req->newptr)
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resettodr();
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return (error);
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}
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SYSCTL_PROC(_machdep, OID_AUTO, adjkerntz, CTLTYPE_INT | CTLFLAG_RW |
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CTLFLAG_MPSAFE, &adjkerntz, 0, sysctl_machdep_adjkerntz, "I",
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"Local offset from UTC in seconds");
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static int ct_debug;
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SYSCTL_INT(_debug, OID_AUTO, clocktime, CTLFLAG_RWTUN,
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&ct_debug, 0, "Enable printing of clocktime debugging");
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static int wall_cmos_clock;
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SYSCTL_INT(_machdep, OID_AUTO, wall_cmos_clock, CTLFLAG_RW,
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&wall_cmos_clock, 0, "Enables application of machdep.adjkerntz");
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/*--------------------------------------------------------------------*
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* Generic routines to convert between a POSIX date
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* (seconds since 1/1/1970) and yr/mo/day/hr/min/sec
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* Derived from NetBSD arch/hp300/hp300/clock.c
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*/
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#define FEBRUARY 2
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#define days_in_year(y) (leapyear(y) ? 366 : 365)
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#define days_in_month(y, m) \
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(month_days[(m) - 1] + (m == FEBRUARY ? leapyear(y) : 0))
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/* Day of week. Days are counted from 1/1/1970, which was a Thursday */
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#define day_of_week(days) (((days) + 4) % 7)
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static const int month_days[12] = {
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31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
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};
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/*
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* Optimization: using a precomputed count of days between POSIX_BASE_YEAR and
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* some recent year avoids lots of unnecessary loop iterations in conversion.
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* recent_base_days is the number of days before the start of recent_base_year.
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*/
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static const int recent_base_year = 2017;
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static const int recent_base_days = 17167;
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/*
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* This inline avoids some unnecessary modulo operations
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* as compared with the usual macro:
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* ( ((year % 4) == 0 &&
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* (year % 100) != 0) ||
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* ((year % 400) == 0) )
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* It is otherwise equivalent.
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*/
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static int
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leapyear(int year)
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{
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int rv = 0;
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if ((year & 3) == 0) {
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rv = 1;
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if ((year % 100) == 0) {
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rv = 0;
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if ((year % 400) == 0)
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rv = 1;
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}
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}
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return (rv);
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}
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static void
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print_ct(struct clocktime *ct)
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{
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printf("[%04d-%02d-%02d %02d:%02d:%02d]",
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ct->year, ct->mon, ct->day,
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ct->hour, ct->min, ct->sec);
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}
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int
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clock_ct_to_ts(struct clocktime *ct, struct timespec *ts)
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{
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int i, year, days;
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year = ct->year;
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if (ct_debug) {
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printf("ct_to_ts(");
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print_ct(ct);
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printf(")");
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}
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/* Sanity checks. */
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if (ct->mon < 1 || ct->mon > 12 || ct->day < 1 ||
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ct->day > days_in_month(year, ct->mon) ||
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ct->hour > 23 || ct->min > 59 || ct->sec > 59 ||
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(sizeof(time_t) == 4 && year > 2037)) { /* time_t overflow */
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if (ct_debug)
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printf(" = EINVAL\n");
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return (EINVAL);
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}
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/*
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* Compute days since start of time
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* First from years, then from months.
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*/
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if (year >= recent_base_year) {
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i = recent_base_year;
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days = recent_base_days;
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} else {
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i = POSIX_BASE_YEAR;
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days = 0;
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}
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for (; i < year; i++)
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days += days_in_year(i);
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/* Months */
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for (i = 1; i < ct->mon; i++)
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days += days_in_month(year, i);
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days += (ct->day - 1);
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ts->tv_sec = (((time_t)days * 24 + ct->hour) * 60 + ct->min) * 60 +
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ct->sec;
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ts->tv_nsec = ct->nsec;
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if (ct_debug)
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printf(" = %jd.%09ld\n", (intmax_t)ts->tv_sec, ts->tv_nsec);
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return (0);
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}
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void
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clock_ts_to_ct(struct timespec *ts, struct clocktime *ct)
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{
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time_t i, year, days;
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time_t rsec; /* remainder seconds */
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time_t secs;
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secs = ts->tv_sec;
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days = secs / SECDAY;
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rsec = secs % SECDAY;
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ct->dow = day_of_week(days);
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/* Subtract out whole years. */
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if (days >= recent_base_days) {
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year = recent_base_year;
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days -= recent_base_days;
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} else {
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year = POSIX_BASE_YEAR;
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}
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for (; days >= days_in_year(year); year++)
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days -= days_in_year(year);
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ct->year = year;
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/* Subtract out whole months, counting them in i. */
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for (i = 1; days >= days_in_month(year, i); i++)
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days -= days_in_month(year, i);
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ct->mon = i;
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/* Days are what is left over (+1) from all that. */
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ct->day = days + 1;
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/* Hours, minutes, seconds are easy */
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ct->hour = rsec / 3600;
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rsec = rsec % 3600;
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ct->min = rsec / 60;
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rsec = rsec % 60;
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ct->sec = rsec;
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ct->nsec = ts->tv_nsec;
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if (ct_debug) {
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printf("ts_to_ct(%jd.%09ld) = ",
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(intmax_t)ts->tv_sec, ts->tv_nsec);
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print_ct(ct);
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printf("\n");
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}
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KASSERT(ct->year >= 0 && ct->year < 10000,
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("year %d isn't a 4 digit year", ct->year));
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KASSERT(ct->mon >= 1 && ct->mon <= 12,
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("month %d not in 1-12", ct->mon));
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KASSERT(ct->day >= 1 && ct->day <= 31,
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("day %d not in 1-31", ct->day));
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KASSERT(ct->hour >= 0 && ct->hour <= 23,
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("hour %d not in 0-23", ct->hour));
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KASSERT(ct->min >= 0 && ct->min <= 59,
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("minute %d not in 0-59", ct->min));
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/* Not sure if this interface needs to handle leapseconds or not. */
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KASSERT(ct->sec >= 0 && ct->sec <= 60,
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("seconds %d not in 0-60", ct->sec));
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}
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int
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utc_offset(void)
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{
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return (tz_minuteswest * 60 + (wall_cmos_clock ? adjkerntz : 0));
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}
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