libcoap  4.3.0rc1
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  * This file is part of the CoAP library libcoap. Please see
6  * README for terms of use.
7  */
8 
9 #include "coap2/coap_internal.h"
10 
11 #ifdef HAVE_TIME_H
12 #include <time.h>
13 #ifdef HAVE_SYS_TIME_H
14 #include <sys/time.h>
15 #endif
16 #ifdef HAVE_UNISTD_H
17 #include <unistd.h> /* _POSIX_TIMERS */
18 #endif
19 #ifdef HAVE_WINSOCK2_H
20 #include <winsock2.h>
21 #include <stdint.h>
22 #endif
23 
24 static coap_tick_t coap_clock_offset = 0;
25 
26 #if _POSIX_TIMERS && !defined(__APPLE__)
27  /* _POSIX_TIMERS is > 0 when clock_gettime() is available */
28 
29  /* Use real-time clock for correct timestamps in coap_log(). */
30 #define COAP_CLOCK CLOCK_REALTIME
31 #endif
32 
33 #ifdef HAVE_WINSOCK2_H
34 static int
35 gettimeofday(struct timeval *tp, TIME_ZONE_INFORMATION *tzp) {
36  (void)tzp;
37  static const uint64_t s_tUnixEpoch = 116444736000000000Ui64;
38 
39  FILETIME file_time;
40  ULARGE_INTEGER time;
41  uint64_t tUsSinceUnicEpoch;
42 
43  GetSystemTimeAsFileTime( &file_time );
44  time.LowPart = file_time.dwLowDateTime;
45  time.HighPart = file_time.dwHighDateTime;
46  tUsSinceUnicEpoch = ( time.QuadPart - s_tUnixEpoch ) / 10;
47 
48  tp->tv_sec = (long)(tUsSinceUnicEpoch / 1000000);
49  tp->tv_usec = (long)(tUsSinceUnicEpoch % 1000000);
50  return 0;
51 }
52 #endif
53 
54 void
55 coap_clock_init(void) {
56 #ifdef COAP_CLOCK
57  struct timespec tv;
58  clock_gettime(COAP_CLOCK, &tv);
59 #else /* _POSIX_TIMERS */
60  struct timeval tv;
61  gettimeofday(&tv, NULL);
62 #endif /* not _POSIX_TIMERS */
63 
64  coap_clock_offset = tv.tv_sec;
65 }
66 
67 /* creates a Qx.frac from fval */
68 #define Q(frac,fval) ((1 << (frac)) * (fval))
69 
70 /* number of frac bits for sub-seconds */
71 #define FRAC 10
72 
73 /* rounds val up and right shifts by frac positions */
74 #define SHR_FP(val,frac) (((coap_tick_t)((val) + (1 << ((frac) - 1)))) >> (frac))
75 
76 void
78  coap_tick_t tmp;
79 
80 #ifdef COAP_CLOCK
81  struct timespec tv;
82  clock_gettime(COAP_CLOCK, &tv);
83  /* Possible errors are (see clock_gettime(2)):
84  * EFAULT tp points outside the accessible address space.
85  * EINVAL The clk_id specified is not supported on this system.
86  * Both cases should not be possible here.
87  */
88 
89  tmp = SHR_FP(tv.tv_nsec * Q(FRAC, (COAP_TICKS_PER_SECOND/1000000000.0)), FRAC);
90 #else /* _POSIX_TIMERS */
91  /* Fall back to gettimeofday() */
92 
93  struct timeval tv;
94  gettimeofday(&tv, NULL);
95  /* Possible errors are (see gettimeofday(2)):
96  * EFAULT One of tv or tz pointed outside the accessible address space.
97  * EINVAL Timezone (or something else) is invalid.
98  * Both cases should not be possible here.
99  */
100 
101  tmp = SHR_FP(tv.tv_usec * Q(FRAC, (COAP_TICKS_PER_SECOND/1000000.0)), FRAC);
102 #endif /* not _POSIX_TIMERS */
103 
104  /* Finally, convert temporary FP representation to multiple of
105  * COAP_TICKS_PER_SECOND */
106  *t = tmp + (tv.tv_sec - coap_clock_offset) * COAP_TICKS_PER_SECOND;
107 }
108 
111  return coap_clock_offset + (t / COAP_TICKS_PER_SECOND);
112 }
113 
114 uint64_t coap_ticks_to_rt_us(coap_tick_t t) {
115  return (uint64_t)coap_clock_offset * 1000000 + (uint64_t)t * 1000000 / COAP_TICKS_PER_SECOND;
116 }
117 
119  return (coap_tick_t)((t - (uint64_t)coap_clock_offset * 1000000) * COAP_TICKS_PER_SECOND / 1000000);
120 }
121 
122 #undef Q
123 #undef FRAC
124 #undef SHR_FP
125 
126 #else /* HAVE_TIME_H */
127 
128 /* make compilers happy that do not like empty modules */
130 {
131 }
132 
133 #endif /* not HAVE_TIME_H */
134 
Pulls together all the internal only header files.
COAP_STATIC_INLINE void dummy(void)
Definition: coap_time.c:129
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:125
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:120
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:135
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:38
#define SHR_FP(val, frac)
#define Q(frac, fval)
creates a Qx.frac from fval in coap_fixed_point_t
Definition: net.c:85