1 /* $NetBSD: clock_subr.c,v 1.27 2016/08/15 15:51:39 jakllsch Exp $ */
2
3 /*
4 * Copyright (c) 1988 University of Utah.
5 * Copyright (c) 1982, 1990, 1993
6 * The Regents of the University of California. All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * the Systems Programming Group of the University of Utah Computer
10 * Science Department.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * from: Utah $Hdr: clock.c 1.18 91/01/21$
37 *
38 * @(#)clock.c 8.2 (Berkeley) 1/12/94
39 */
40
41 /*
42 * Generic routines to convert between a POSIX date
43 * (seconds since 1/1/1970) and yr/mo/day/hr/min/sec
44 * Derived from arch/hp300/hp300/clock.c
45 */
46
47 #if HAVE_NBTOOL_CONFIG_H
48 #include "nbtool_config.h"
49 #endif /* HAVE_NBTOOL_CONFIG_H */
50
51 #ifdef _KERNEL
52 #include <sys/cdefs.h>
53 __KERNEL_RCSID(0, "$NetBSD: clock_subr.c,v 1.27 2016/08/15 15:51:39 jakllsch Exp $");
54
55 #include <sys/param.h>
56 #include <sys/systm.h>
57 #include <sys/errno.h>
58 #else /* ! _KERNEL */
59 #include <string.h>
60 #include <time.h>
61 #include <errno.h>
62 #endif /* ! _KERNEL */
63
64 #include "../sys/clock.h"
65 #include <dev/clock_subr.h>
66
67 #define FEBRUARY 2
68
69 /* for easier alignment:
70 * time from the epoch to 2001 (there were 8 leap years): */
71 #define DAYSTO2001 (365*31+8)
72
73 /* 4 year intervals include 1 leap year */
74 #define DAYS4YEARS (365*4+1)
75
76 /* 100 year intervals include 24 leap years */
77 #define DAYS100YEARS (365*100+24)
78
79 /* 400 year intervals include 97 leap years */
80 #define DAYS400YEARS (365*400+97)
81
82 time_t
clock_ymdhms_to_secs(struct clock_ymdhms * dt)83 clock_ymdhms_to_secs(struct clock_ymdhms *dt)
84 {
85 uint64_t secs, i, year, days;
86
87 year = dt->dt_year;
88
89 /*
90 * Compute days since start of time
91 * First from years, then from months.
92 */
93 if (year < POSIX_BASE_YEAR)
94 return -1;
95 days = 0;
96 if (is_leap_year(year) && dt->dt_mon > FEBRUARY)
97 days++;
98
99 if (year < 2001) {
100 /* simple way for early years */
101 for (i = POSIX_BASE_YEAR; i < year; i++)
102 days += days_per_year(i);
103 } else {
104 /* years are properly aligned */
105 days += DAYSTO2001;
106 year -= 2001;
107
108 i = year / 400;
109 days += i * DAYS400YEARS;
110 year -= i * 400;
111
112 i = year / 100;
113 days += i * DAYS100YEARS;
114 year -= i * 100;
115
116 i = year / 4;
117 days += i * DAYS4YEARS;
118 year -= i * 4;
119
120 for (i = dt->dt_year-year; i < dt->dt_year; i++)
121 days += days_per_year(i);
122 }
123
124
125 /* Months */
126 for (i = 1; i < dt->dt_mon; i++)
127 days += days_in_month(i);
128 days += (dt->dt_day - 1);
129
130 /* Add hours, minutes, seconds. */
131 secs = (((uint64_t)days
132 * 24 + dt->dt_hour)
133 * 60 + dt->dt_min)
134 * 60 + dt->dt_sec;
135
136 if ((time_t)secs < 0 || secs > __type_max(time_t))
137 return -1;
138 return secs;
139 }
140
141 int
clock_secs_to_ymdhms(time_t secs,struct clock_ymdhms * dt)142 clock_secs_to_ymdhms(time_t secs, struct clock_ymdhms *dt)
143 {
144 int leap;
145 uint64_t i;
146 time_t days;
147 time_t rsec; /* remainder seconds */
148
149 if (secs < 0)
150 return EINVAL;
151
152 days = secs / SECS_PER_DAY;
153 rsec = secs % SECS_PER_DAY;
154
155 /* Day of week (Note: 1/1/1970 was a Thursday) */
156 dt->dt_wday = (days + 4) % 7;
157
158 if (days >= DAYSTO2001) {
159 days -= DAYSTO2001;
160 dt->dt_year = 2001;
161
162 i = days / DAYS400YEARS;
163 days -= i*DAYS400YEARS;
164 dt->dt_year += i*400;
165
166 i = days / DAYS100YEARS;
167 days -= i*DAYS100YEARS;
168 dt->dt_year += i*100;
169
170 i = days / DAYS4YEARS;
171 days -= i*DAYS4YEARS;
172 dt->dt_year += i*4;
173
174 for (i = dt->dt_year; days >= days_per_year(i); i++)
175 days -= days_per_year(i);
176 dt->dt_year = i;
177 } else {
178 /* Subtract out whole years, counting them in i. */
179 for (i = POSIX_BASE_YEAR; days >= days_per_year(i); i++)
180 days -= days_per_year(i);
181 dt->dt_year = i;
182 }
183
184 /* Subtract out whole months, counting them in i. */
185 for (leap = 0, i = 1; days >= days_in_month(i)+leap; i++) {
186 days -= days_in_month(i)+leap;
187 if (i == 1 && is_leap_year(dt->dt_year))
188 leap = 1;
189 else
190 leap = 0;
191 }
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 / SECS_PER_HOUR;
199 rsec = rsec % SECS_PER_HOUR;
200 dt->dt_min = rsec / SECS_PER_MINUTE;
201 rsec = rsec % SECS_PER_MINUTE;
202 dt->dt_sec = rsec;
203
204 return 0;
205 }
206