/* $OpenBSD: clock_subr.c,v 1.6 2016/08/26 07:09:56 guenther 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/time.h> #include <sys/systm.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 = (time_t)((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 */ memcpy(mthdays, month_days, 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; }