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util: add check that makes sure time_t and TIME_T_MAX work the way we assume they do
[thirdparty/systemd.git] / src / basic / time-util.h
1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
2
3 #pragma once
4
5 /***
6 This file is part of systemd.
7
8 Copyright 2010 Lennart Poettering
9
10 systemd is free software; you can redistribute it and/or modify it
11 under the terms of the GNU Lesser General Public License as published by
12 the Free Software Foundation; either version 2.1 of the License, or
13 (at your option) any later version.
14
15 systemd is distributed in the hope that it will be useful, but
16 WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 Lesser General Public License for more details.
19
20 You should have received a copy of the GNU Lesser General Public License
21 along with systemd; If not, see <http://www.gnu.org/licenses/>.
22 ***/
23
24 #include <inttypes.h>
25 #include <stdbool.h>
26 #include <stddef.h>
27 #include <stdint.h>
28 #include <stdio.h>
29 #include <time.h>
30
31 typedef uint64_t usec_t;
32 typedef uint64_t nsec_t;
33
34 #define NSEC_FMT "%" PRIu64
35 #define USEC_FMT "%" PRIu64
36
37 #include "macro.h"
38
39 typedef struct dual_timestamp {
40 usec_t realtime;
41 usec_t monotonic;
42 } dual_timestamp;
43
44 #define USEC_INFINITY ((usec_t) -1)
45 #define NSEC_INFINITY ((nsec_t) -1)
46
47 #define MSEC_PER_SEC 1000ULL
48 #define USEC_PER_SEC ((usec_t) 1000000ULL)
49 #define USEC_PER_MSEC ((usec_t) 1000ULL)
50 #define NSEC_PER_SEC ((nsec_t) 1000000000ULL)
51 #define NSEC_PER_MSEC ((nsec_t) 1000000ULL)
52 #define NSEC_PER_USEC ((nsec_t) 1000ULL)
53
54 #define USEC_PER_MINUTE ((usec_t) (60ULL*USEC_PER_SEC))
55 #define NSEC_PER_MINUTE ((nsec_t) (60ULL*NSEC_PER_SEC))
56 #define USEC_PER_HOUR ((usec_t) (60ULL*USEC_PER_MINUTE))
57 #define NSEC_PER_HOUR ((nsec_t) (60ULL*NSEC_PER_MINUTE))
58 #define USEC_PER_DAY ((usec_t) (24ULL*USEC_PER_HOUR))
59 #define NSEC_PER_DAY ((nsec_t) (24ULL*NSEC_PER_HOUR))
60 #define USEC_PER_WEEK ((usec_t) (7ULL*USEC_PER_DAY))
61 #define NSEC_PER_WEEK ((nsec_t) (7ULL*NSEC_PER_DAY))
62 #define USEC_PER_MONTH ((usec_t) (2629800ULL*USEC_PER_SEC))
63 #define NSEC_PER_MONTH ((nsec_t) (2629800ULL*NSEC_PER_SEC))
64 #define USEC_PER_YEAR ((usec_t) (31557600ULL*USEC_PER_SEC))
65 #define NSEC_PER_YEAR ((nsec_t) (31557600ULL*NSEC_PER_SEC))
66
67 #define FORMAT_TIMESTAMP_MAX ((4*4+1)+11+9+4+1) /* weekdays can be unicode */
68 #define FORMAT_TIMESTAMP_WIDTH 28 /* when outputting, assume this width */
69 #define FORMAT_TIMESTAMP_RELATIVE_MAX 256
70 #define FORMAT_TIMESPAN_MAX 64
71
72 #define TIME_T_MAX (time_t)((UINTMAX_C(1) << ((sizeof(time_t) << 3) - 1)) - 1)
73
74 #define DUAL_TIMESTAMP_NULL ((struct dual_timestamp) { 0ULL, 0ULL })
75
76 usec_t now(clockid_t clock);
77 nsec_t now_nsec(clockid_t clock);
78
79 dual_timestamp* dual_timestamp_get(dual_timestamp *ts);
80 dual_timestamp* dual_timestamp_from_realtime(dual_timestamp *ts, usec_t u);
81 dual_timestamp* dual_timestamp_from_monotonic(dual_timestamp *ts, usec_t u);
82 dual_timestamp* dual_timestamp_from_boottime_or_monotonic(dual_timestamp *ts, usec_t u);
83
84 static inline bool dual_timestamp_is_set(dual_timestamp *ts) {
85 return ((ts->realtime > 0 && ts->realtime != USEC_INFINITY) ||
86 (ts->monotonic > 0 && ts->monotonic != USEC_INFINITY));
87 }
88
89 usec_t timespec_load(const struct timespec *ts) _pure_;
90 struct timespec *timespec_store(struct timespec *ts, usec_t u);
91
92 usec_t timeval_load(const struct timeval *tv) _pure_;
93 struct timeval *timeval_store(struct timeval *tv, usec_t u);
94
95 nsec_t timespec_load_nsec(const struct timespec *ts) _pure_;
96
97 char *format_timestamp(char *buf, size_t l, usec_t t);
98 char *format_timestamp_utc(char *buf, size_t l, usec_t t);
99 char *format_timestamp_us(char *buf, size_t l, usec_t t);
100 char *format_timestamp_us_utc(char *buf, size_t l, usec_t t);
101 char *format_timestamp_relative(char *buf, size_t l, usec_t t);
102 char *format_timespan(char *buf, size_t l, usec_t t, usec_t accuracy);
103
104 void dual_timestamp_serialize(FILE *f, const char *name, dual_timestamp *t);
105 int dual_timestamp_deserialize(const char *value, dual_timestamp *t);
106
107 int parse_timestamp(const char *t, usec_t *usec);
108
109 int parse_sec(const char *t, usec_t *usec);
110 int parse_time(const char *t, usec_t *usec, usec_t default_unit);
111 int parse_nsec(const char *t, nsec_t *nsec);
112
113 bool ntp_synced(void);
114
115 int get_timezones(char ***l);
116 bool timezone_is_valid(const char *name);
117
118 clockid_t clock_boottime_or_monotonic(void);
119
120 #define xstrftime(buf, fmt, tm) \
121 assert_message_se(strftime(buf, ELEMENTSOF(buf), fmt, tm) > 0, \
122 "xstrftime: " #buf "[] must be big enough")
123
124 int get_timezone(char **timezone);
125
126 time_t mktime_or_timegm(struct tm *tm, bool utc);
127 struct tm *localtime_or_gmtime_r(const time_t *t, struct tm *tm, bool utc);
128
129 unsigned long usec_to_jiffies(usec_t usec);
130
131 static inline usec_t usec_add(usec_t a, usec_t b) {
132 usec_t c;
133
134 /* Adds two time values, and makes sure USEC_INFINITY as input results as USEC_INFINITY in output, and doesn't
135 * overflow. */
136
137 c = a + b;
138 if (c < a || c < b) /* overflow check */
139 return USEC_INFINITY;
140
141 return c;
142 }