lib/monotime.h

   1 /*
   2  * Copyright (c) 2017  David Lamparter, for NetDEF, Inc.
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  */
  16
  17 #ifndef _FRR_MONOTIME_H
  18 #define _FRR_MONOTIME_H
  19
  20 #include <stdint.h>
  21 #include <time.h>
  22 #include <sys/time.h>
  23
  24 #ifdef __cplusplus
  25 extern "C" {
  26 #endif
  27
  28 #ifndef TIMESPEC_TO_TIMEVAL
  29 /* should be in sys/time.h on BSD & Linux libcs */
  30 #define TIMESPEC_TO_TIMEVAL(tv, ts)                                            \
  31         do {                                                                   \
  32                 (tv)->tv_sec = (ts)->tv_sec;                                   \
  33                 (tv)->tv_usec = (ts)->tv_nsec / 1000;                          \
  34         } while (0)
  35 #endif
  36 #ifndef TIMEVAL_TO_TIMESPEC
  37 /* should be in sys/time.h on BSD & Linux libcs */
  38 #define TIMEVAL_TO_TIMESPEC(tv, ts)                                            \
  39         do {                                                                   \
  40                 (ts)->tv_sec = (tv)->tv_sec;                                   \
  41                 (ts)->tv_nsec = (tv)->tv_usec * 1000;                          \
  42         } while (0)
  43 #endif
  44
  45 static inline time_t monotime(struct timeval *tvo)
  46 {
  47         struct timespec ts;
  48
  49         clock_gettime(CLOCK_MONOTONIC, &ts);
  50         if (tvo) {
  51                 TIMESPEC_TO_TIMEVAL(tvo, &ts);
  52         }
  53         return ts.tv_sec;
  54 }
  55
  56 #define ONE_DAY_SECOND 60*60*24
  57 #define ONE_WEEK_SECOND ONE_DAY_SECOND*7
  58 #define ONE_YEAR_SECOND ONE_DAY_SECOND*365
  59
  60 /* the following two return microseconds, not time_t!
  61  *
  62  * also, they're negative forms of each other, but having both makes the
  63  * code more readable
  64  */
  65 static inline int64_t monotime_since(const struct timeval *ref,
  66                                      struct timeval *out)
  67 {
  68         struct timeval tv;
  69         monotime(&tv);
  70         timersub(&tv, ref, &tv);
  71         if (out)
  72                 *out = tv;
  73         return (int64_t)tv.tv_sec * 1000000LL + tv.tv_usec;
  74 }
  75
  76 static inline int64_t monotime_until(const struct timeval *ref,
  77                                      struct timeval *out)
  78 {
  79         struct timeval tv;
  80         monotime(&tv);
  81         timersub(ref, &tv, &tv);
  82         if (out)
  83                 *out = tv;
  84         return (int64_t)tv.tv_sec * 1000000LL + tv.tv_usec;
  85 }
  86
  87 static inline time_t monotime_to_realtime(const struct timeval *mono,
  88                                           struct timeval *realout)
  89 {
  90         struct timeval delta, real;
  91
  92         monotime_since(mono, &delta);
  93         gettimeofday(&real, NULL);
  94
  95         timersub(&real, &delta, &real);
  96         if (realout)
  97                 *realout = real;
  98         return real.tv_sec;
  99 }
 100
 101 /* Char buffer size for time-to-string api */
 102 #define MONOTIME_STRLEN 32
 103
 104 static inline char *time_to_string(time_t ts, char *buf)
 105 {
 106         struct timeval tv;
 107         time_t tbuf;
 108
 109         monotime(&tv);
 110         tbuf = time(NULL) - (tv.tv_sec - ts);
 111
 112         return ctime_r(&tbuf, buf);
 113 }
 114
 115 #ifdef __cplusplus
 116 }
 117 #endif
 118
 119 #endif /* _FRR_MONOTIME_H */