1 /*
2 * Copyright (c) 2008-2013 Apple Inc. All rights reserved.
3 *
4 * @APPLE_APACHE_LICENSE_HEADER_START@
5 *
6 * Licensed under the Apache License, Version 2.0 (the "License");
7 * you may not use this file except in compliance with the License.
8 * You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 *
18 * @APPLE_APACHE_LICENSE_HEADER_END@
19 */
20
21 #include "internal.h"
22
23 uint64_t
_dispatch_get_nanoseconds(void)24 _dispatch_get_nanoseconds(void)
25 {
26 #if !TARGET_OS_WIN32
27 struct timeval now;
28 int r = gettimeofday(&now, NULL);
29 dispatch_assert_zero(r);
30 dispatch_assert(sizeof(NSEC_PER_SEC) == 8);
31 dispatch_assert(sizeof(NSEC_PER_USEC) == 8);
32 return (uint64_t)now.tv_sec * NSEC_PER_SEC +
33 (uint64_t)now.tv_usec * NSEC_PER_USEC;
34 #else /* TARGET_OS_WIN32 */
35 // FILETIME is 100-nanosecond intervals since January 1, 1601 (UTC).
36 FILETIME ft;
37 ULARGE_INTEGER li;
38 GetSystemTimeAsFileTime(&ft);
39 li.LowPart = ft.dwLowDateTime;
40 li.HighPart = ft.dwHighDateTime;
41 return li.QuadPart * 100ull;
42 #endif /* TARGET_OS_WIN32 */
43 }
44
45 #if !(defined(__i386__) || defined(__x86_64__) || !HAVE_MACH_ABSOLUTE_TIME) \
46 || TARGET_OS_WIN32
47 DISPATCH_CACHELINE_ALIGN _dispatch_host_time_data_s _dispatch_host_time_data = {
48 .ratio_1_to_1 = true,
49 };
50
51 void
_dispatch_get_host_time_init(void * context DISPATCH_UNUSED)52 _dispatch_get_host_time_init(void *context DISPATCH_UNUSED)
53 {
54 #if !TARGET_OS_WIN32
55 mach_timebase_info_data_t tbi;
56 (void)dispatch_assume_zero(mach_timebase_info(&tbi));
57 _dispatch_host_time_data.frac = tbi.numer;
58 _dispatch_host_time_data.frac /= tbi.denom;
59 _dispatch_host_time_data.ratio_1_to_1 = (tbi.numer == tbi.denom);
60 #else
61 LARGE_INTEGER freq;
62 dispatch_assume(QueryPerformanceFrequency(&freq));
63 _dispatch_host_time_data.frac = (long double)NSEC_PER_SEC /
64 (long double)freq.QuadPart;
65 _dispatch_host_time_data.ratio_1_to_1 = (freq.QuadPart == 1);
66 #endif /* TARGET_OS_WIN32 */
67 }
68 #endif
69
70 dispatch_time_t
dispatch_time(dispatch_time_t inval,int64_t delta)71 dispatch_time(dispatch_time_t inval, int64_t delta)
72 {
73 uint64_t offset;
74 if (inval == DISPATCH_TIME_FOREVER) {
75 return DISPATCH_TIME_FOREVER;
76 }
77 if ((int64_t)inval < 0) {
78 // wall clock
79 if (delta >= 0) {
80 offset = (uint64_t)delta;
81 if ((int64_t)(inval -= offset) >= 0) {
82 return DISPATCH_TIME_FOREVER; // overflow
83 }
84 return inval;
85 } else {
86 offset = (uint64_t)-delta;
87 if ((int64_t)(inval += offset) >= -1) {
88 // -1 is special == DISPATCH_TIME_FOREVER == forever
89 return (dispatch_time_t)-2ll; // underflow
90 }
91 return inval;
92 }
93 }
94 // mach clock
95 if (inval == 0) {
96 inval = _dispatch_absolute_time();
97 }
98 if (delta >= 0) {
99 offset = _dispatch_time_nano2mach((uint64_t)delta);
100 if ((int64_t)(inval += offset) <= 0) {
101 return DISPATCH_TIME_FOREVER; // overflow
102 }
103 return inval;
104 } else {
105 offset = _dispatch_time_nano2mach((uint64_t)-delta);
106 if ((int64_t)(inval -= offset) < 1) {
107 return 1; // underflow
108 }
109 return inval;
110 }
111 }
112
113 dispatch_time_t
dispatch_walltime(const struct timespec * inval,int64_t delta)114 dispatch_walltime(const struct timespec *inval, int64_t delta)
115 {
116 int64_t nsec;
117 if (inval) {
118 nsec = inval->tv_sec * 1000000000ll + inval->tv_nsec;
119 } else {
120 nsec = (int64_t)_dispatch_get_nanoseconds();
121 }
122 nsec += delta;
123 if (nsec <= 1) {
124 // -1 is special == DISPATCH_TIME_FOREVER == forever
125 return delta >= 0 ? DISPATCH_TIME_FOREVER : (dispatch_time_t)-2ll;
126 }
127 return (dispatch_time_t)-nsec;
128 }
129
130 uint64_t
_dispatch_timeout(dispatch_time_t when)131 _dispatch_timeout(dispatch_time_t when)
132 {
133 dispatch_time_t now;
134 if (when == DISPATCH_TIME_FOREVER) {
135 return DISPATCH_TIME_FOREVER;
136 }
137 if (when == 0) {
138 return 0;
139 }
140 if ((int64_t)when < 0) {
141 when = (dispatch_time_t)-(int64_t)when;
142 now = _dispatch_get_nanoseconds();
143 return now >= when ? 0 : when - now;
144 }
145 now = _dispatch_absolute_time();
146 return now >= when ? 0 : _dispatch_time_mach2nano(when - now);
147 }
148