libcoap  4.3.0
coap_time.c
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1 /* coap_time.c -- Clock Handling
2  *
3  * Copyright (C) 2015 Olaf Bergmann <bergmann@tzi.org>
4  *
5  * SPDX-License-Identifier: BSD-2-Clause
6  *
7  * This file is part of the CoAP library libcoap. Please see
8  * README for terms of use.
9  */
10 
11 #include "coap3/coap_internal.h"
12 
13 #ifdef HAVE_TIME_H
14 #include <time.h>
15 #ifdef HAVE_SYS_TIME_H
16 #include <sys/time.h>
17 #endif
18 #ifdef HAVE_UNISTD_H
19 #include <unistd.h> /* _POSIX_TIMERS */
20 #endif
21 #ifdef HAVE_WINSOCK2_H
22 #include <winsock2.h>
23 #include <stdint.h>
24 #endif
25 
26 static coap_tick_t coap_clock_offset = 0;
27 
28 #if _POSIX_TIMERS && !defined(__APPLE__)
29  /* _POSIX_TIMERS is > 0 when clock_gettime() is available */
30 
31  /* Use real-time clock for correct timestamps in coap_log(). */
32 #define COAP_CLOCK CLOCK_REALTIME
33 #endif
34 
35 #ifdef HAVE_WINSOCK2_H
36 static int
37 gettimeofday(struct timeval *tp, TIME_ZONE_INFORMATION *tzp) {
38  (void)tzp;
39  static const uint64_t s_tUnixEpoch = 116444736000000000Ui64;
40 
41  FILETIME file_time;
42  ULARGE_INTEGER time;
43  uint64_t tUsSinceUnicEpoch;
44 
45  GetSystemTimeAsFileTime( &file_time );
46  time.LowPart = file_time.dwLowDateTime;
47  time.HighPart = file_time.dwHighDateTime;
48  tUsSinceUnicEpoch = ( time.QuadPart - s_tUnixEpoch ) / 10;
49 
50  tp->tv_sec = (long)(tUsSinceUnicEpoch / 1000000);
51  tp->tv_usec = (long)(tUsSinceUnicEpoch % 1000000);
52  return 0;
53 }
54 #endif
55 
56 void
57 coap_clock_init(void) {
58 #ifdef COAP_CLOCK
59  struct timespec tv;
60  clock_gettime(COAP_CLOCK, &tv);
61 #else /* _POSIX_TIMERS */
62  struct timeval tv;
63  gettimeofday(&tv, NULL);
64 #endif /* not _POSIX_TIMERS */
65 
66  coap_clock_offset = tv.tv_sec;
67 }
68 
69 /* creates a Qx.frac from fval */
70 #define Q(frac,fval) ((1 << (frac)) * (fval))
71 
72 /* number of frac bits for sub-seconds */
73 #define FRAC 10
74 
75 /* rounds val up and right shifts by frac positions */
76 #define SHR_FP(val,frac) (((coap_tick_t)((val) + (1 << ((frac) - 1)))) >> (frac))
77 
78 void
80  coap_tick_t tmp;
81 
82 #ifdef COAP_CLOCK
83  struct timespec tv;
84  clock_gettime(COAP_CLOCK, &tv);
85  /* Possible errors are (see clock_gettime(2)):
86  * EFAULT tp points outside the accessible address space.
87  * EINVAL The clk_id specified is not supported on this system.
88  * Both cases should not be possible here.
89  */
90 
91  tmp = SHR_FP(tv.tv_nsec * Q(FRAC, (COAP_TICKS_PER_SECOND/1000000000.0)), FRAC);
92 #else /* _POSIX_TIMERS */
93  /* Fall back to gettimeofday() */
94 
95  struct timeval tv;
96  gettimeofday(&tv, NULL);
97  /* Possible errors are (see gettimeofday(2)):
98  * EFAULT One of tv or tz pointed outside the accessible address space.
99  * EINVAL Timezone (or something else) is invalid.
100  * Both cases should not be possible here.
101  */
102 
103  tmp = SHR_FP(tv.tv_usec * Q(FRAC, (COAP_TICKS_PER_SECOND/1000000.0)), FRAC);
104 #endif /* not _POSIX_TIMERS */
105 
106  /* Finally, convert temporary FP representation to multiple of
107  * COAP_TICKS_PER_SECOND */
108  *t = tmp + (tv.tv_sec - coap_clock_offset) * COAP_TICKS_PER_SECOND;
109 }
110 
113  return coap_clock_offset + (t / COAP_TICKS_PER_SECOND);
114 }
115 
116 uint64_t coap_ticks_to_rt_us(coap_tick_t t) {
117  return (uint64_t)coap_clock_offset * 1000000 + (uint64_t)t * 1000000 / COAP_TICKS_PER_SECOND;
118 }
119 
121  return (coap_tick_t)((t - (uint64_t)coap_clock_offset * 1000000) * COAP_TICKS_PER_SECOND / 1000000);
122 }
123 
124 #undef Q
125 #undef FRAC
126 #undef SHR_FP
127 
128 #else /* HAVE_TIME_H */
129 
130 /* make compilers happy that do not like empty modules */
132 {
133 }
134 
135 #endif /* not HAVE_TIME_H */
136 
Pulls together all the internal only header files.
COAP_STATIC_INLINE void dummy(void)
Definition: coap_time.c:131
coap_tick_t coap_ticks_from_rt_us(uint64_t t)
Helper function that converts POSIX wallclock time in us to coap ticks.
void coap_ticks(coap_tick_t *t)
Sets t to the internal time with COAP_TICKS_PER_SECOND resolution.
time_t coap_time_t
CoAP time in seconds since epoch.
Definition: coap_time.h:127
void coap_clock_init(void)
Initializes the internal clock.
uint64_t coap_tick_t
This data type represents internal timer ticks with COAP_TICKS_PER_SECOND resolution.
Definition: coap_time.h:122
coap_time_t coap_ticks_to_rt(coap_tick_t t)
Helper function that converts coap ticks to wallclock time.
#define COAP_TICKS_PER_SECOND
Use ms resolution on POSIX systems.
Definition: coap_time.h:137
uint64_t coap_ticks_to_rt_us(coap_tick_t t)
Helper function that converts coap ticks to POSIX wallclock time in us.
#define COAP_STATIC_INLINE
Definition: libcoap.h:40
#define SHR_FP(val, frac)
#define Q(frac, fval)
creates a Qx.frac from fval in coap_fixed_point_t
Definition: net.c:87