clock_subr.c revision 1.12.74.1
1 /* $NetBSD: clock_subr.c,v 1.12.74.1 2009/05/04 08:12:32 yamt Exp $ */ 2 3 /* 4 * Copyright (c) 1982, 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * the Systems Programming Group of the University of Utah Computer 9 * Science Department. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * from: Utah $Hdr: clock.c 1.18 91/01/21$ 36 * 37 * @(#)clock.c 8.2 (Berkeley) 1/12/94 38 */ 39 40 /* 41 * Copyright (c) 1988 University of Utah. 42 * 43 * This code is derived from software contributed to Berkeley by 44 * the Systems Programming Group of the University of Utah Computer 45 * Science Department. 46 * 47 * Redistribution and use in source and binary forms, with or without 48 * modification, are permitted provided that the following conditions 49 * are met: 50 * 1. Redistributions of source code must retain the above copyright 51 * notice, this list of conditions and the following disclaimer. 52 * 2. Redistributions in binary form must reproduce the above copyright 53 * notice, this list of conditions and the following disclaimer in the 54 * documentation and/or other materials provided with the distribution. 55 * 3. All advertising materials mentioning features or use of this software 56 * must display the following acknowledgement: 57 * This product includes software developed by the University of 58 * California, Berkeley and its contributors. 59 * 4. Neither the name of the University nor the names of its contributors 60 * may be used to endorse or promote products derived from this software 61 * without specific prior written permission. 62 * 63 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 64 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 65 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 66 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 67 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 68 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 69 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 70 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 71 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 72 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 73 * SUCH DAMAGE. 74 * 75 * from: Utah $Hdr: clock.c 1.18 91/01/21$ 76 * 77 * @(#)clock.c 8.2 (Berkeley) 1/12/94 78 */ 79 80 /* 81 * Generic routines to convert between a POSIX date 82 * (seconds since 1/1/1970) and yr/mo/day/hr/min/sec 83 * Derived from arch/hp300/hp300/clock.c 84 */ 85 86 #include <sys/cdefs.h> 87 __KERNEL_RCSID(0, "$NetBSD: clock_subr.c,v 1.12.74.1 2009/05/04 08:12:32 yamt Exp $"); 88 89 #include <sys/param.h> 90 #include <sys/systm.h> 91 92 #include <dev/clock_subr.h> 93 94 static inline int leapyear(int year); 95 #define FEBRUARY 2 96 #define days_in_year(a) (leapyear(a) ? 366 : 365) 97 #define days_in_month(a) (month_days[(a) - 1]) 98 99 static const int month_days[12] = { 100 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 101 }; 102 103 /* 104 * This inline avoids some unnecessary modulo operations 105 * as compared with the usual macro: 106 * ( ((year % 4) == 0 && 107 * (year % 100) != 0) || 108 * ((year % 400) == 0) ) 109 * It is otherwise equivalent. 110 */ 111 static inline int 112 leapyear(int year) 113 { 114 int rv = 0; 115 116 if ((year & 3) == 0) { 117 rv = 1; 118 if ((year % 100) == 0) { 119 rv = 0; 120 if ((year % 400) == 0) 121 rv = 1; 122 } 123 } 124 return (rv); 125 } 126 127 time_t 128 clock_ymdhms_to_secs(struct clock_ymdhms *dt) 129 { 130 uint64_t secs; 131 int i, year, days; 132 133 year = dt->dt_year; 134 135 /* 136 * Compute days since start of time 137 * First from years, then from months. 138 */ 139 if (year < POSIX_BASE_YEAR) return -1; 140 days = 0; 141 for (i = POSIX_BASE_YEAR; i < year; i++) 142 days += days_in_year(i); 143 if (leapyear(year) && dt->dt_mon > FEBRUARY) 144 days++; 145 146 /* Months */ 147 for (i = 1; i < dt->dt_mon; i++) 148 days += days_in_month(i); 149 days += (dt->dt_day - 1); 150 151 /* Add hours, minutes, seconds. */ 152 secs = (((uint64_t)days 153 * 24 + dt->dt_hour) 154 * 60 + dt->dt_min) 155 * 60 + dt->dt_sec; 156 157 if ((time_t)secs != secs) return -1; 158 return (secs); 159 } 160 161 void 162 clock_secs_to_ymdhms(time_t secs, struct clock_ymdhms *dt) 163 { 164 int mthdays[12]; 165 int i, days; 166 int rsec; /* remainder seconds */ 167 168 /* 169 * This function uses a local copy of month_days[] 170 * so the copy can be modified (and thread-safe). 171 * See the definition of days_in_month() above. 172 */ 173 memcpy(mthdays, month_days, sizeof(mthdays)); 174 #define month_days mthdays 175 176 days = secs / SECDAY; 177 rsec = secs % SECDAY; 178 179 /* Day of week (Note: 1/1/1970 was a Thursday) */ 180 dt->dt_wday = (days + 4) % 7; 181 182 /* Subtract out whole years, counting them in i. */ 183 for (i = POSIX_BASE_YEAR; days >= days_in_year(i); i++) 184 days -= days_in_year(i); 185 dt->dt_year = i; 186 187 /* Subtract out whole months, counting them in i. */ 188 if (leapyear(i)) 189 days_in_month(FEBRUARY) = 29; 190 for (i = 1; days >= days_in_month(i); i++) 191 days -= days_in_month(i); 192 dt->dt_mon = i; 193 194 /* Days are what is left over (+1) from all that. */ 195 dt->dt_day = days + 1; 196 197 /* Hours, minutes, seconds are easy */ 198 dt->dt_hour = rsec / 3600; 199 rsec = rsec % 3600; 200 dt->dt_min = rsec / 60; 201 rsec = rsec % 60; 202 dt->dt_sec = rsec; 203 #undef month_days 204 } 205
Indexes created Tue Sep 30 20:09:53 GMT 2025