1 /*
2  * Copyright (C) 2015 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef ART_LIBARTBASE_BASE_TIME_UTILS_H_
18 #define ART_LIBARTBASE_BASE_TIME_UTILS_H_
19 
20 #ifdef _WIN32
21 #include <stdio.h>  // Needed for correct macro definitions.
22 #endif
23 
24 #include <time.h>
25 
26 #include <cstdint>
27 #include <string>
28 
29 namespace art {
30 
31 enum TimeUnit {
32   kTimeUnitNanosecond,
33   kTimeUnitMicrosecond,
34   kTimeUnitMillisecond,
35   kTimeUnitSecond,
36 };
37 
38 // Constants for common time periods.
39 constexpr unsigned int kOneMinuteInSeconds = 60;
40 constexpr unsigned int kOneHourInSeconds = 60 * kOneMinuteInSeconds;
41 
42 // Returns a human-readable time string which prints every nanosecond while trying to limit the
43 // number of trailing zeros. Prints using the largest human readable unit up to a second.
44 // e.g. "1ms", "1.000000001s", "1.001us"
45 std::string PrettyDuration(uint64_t nano_duration, size_t max_fraction_digits = 3);
46 
47 // Format a nanosecond time to specified units.
48 std::string FormatDuration(uint64_t nano_duration, TimeUnit time_unit,
49                            size_t max_fraction_digits);
50 
51 // Get the appropriate unit for a nanosecond duration.
52 TimeUnit GetAppropriateTimeUnit(uint64_t nano_duration);
53 
54 // Get the divisor to convert from a nanoseconds to a time unit.
55 uint64_t GetNsToTimeUnitDivisor(TimeUnit time_unit);
56 
57 // Returns the current date in ISO yyyy-mm-dd hh:mm:ss format.
58 std::string GetIsoDate();
59 
60 // Returns the monotonic time since some unspecified starting point in milliseconds.
61 uint64_t MilliTime();
62 
63 // Returns the monotonic time since some unspecified starting point in microseconds.
64 uint64_t MicroTime();
65 
66 // Returns the monotonic time since some unspecified starting point in nanoseconds.
67 uint64_t NanoTime();
68 
69 // Returns the thread-specific CPU-time clock in nanoseconds or -1 if unavailable.
70 uint64_t ThreadCpuNanoTime();
71 
72 // Returns the process CPU-time clock in nanoseconds or -1 if unavailable.
73 uint64_t ProcessCpuNanoTime();
74 
75 // Converts the given number of nanoseconds to milliseconds.
76 static constexpr uint64_t NsToMs(uint64_t ns) {
77   return ns / 1000 / 1000;
78 }
79 
80 // Converts the given number of nanoseconds to microseconds.
81 static constexpr uint64_t NsToUs(uint64_t ns) {
82   return ns / 1000;
83 }
84 
85 // Converts the given number of milliseconds to nanoseconds
86 static constexpr uint64_t MsToNs(uint64_t ms) {
87   return ms * 1000 * 1000;
88 }
89 
90 // Converts the given number of milliseconds to microseconds
91 static constexpr uint64_t MsToUs(uint64_t ms) {
92   return ms * 1000;
93 }
94 
95 static constexpr uint64_t UsToNs(uint64_t us) {
96   return us * 1000;
97 }
98 
99 static constexpr uint64_t SecondsToMs(uint64_t seconds) {
100   return seconds * 1000;
101 }
102 
103 static constexpr time_t SaturatedTimeT(int64_t secs) {
104   if (sizeof(time_t) < sizeof(int64_t)) {
105     return static_cast<time_t>(std::min(secs,
106                                         static_cast<int64_t>(std::numeric_limits<time_t>::max())));
107   } else {
108     return secs;
109   }
110 }
111 
112 #if defined(__APPLE__)
113 #ifndef CLOCK_REALTIME
114 // No clocks to specify on OS/X < 10.12, fake value to pass to routines that require a clock.
115 #define CLOCK_REALTIME 0xebadf00d
116 #endif
117 #endif
118 
119 // Sleep for the given number of nanoseconds, a bad way to handle contention.
120 void NanoSleep(uint64_t ns);
121 
122 // Initialize a timespec to either a relative time (ms,ns), or to the absolute
123 // time corresponding to the indicated clock value plus the supplied offset.
124 void InitTimeSpec(bool absolute, int clock, int64_t ms, int32_t ns, timespec* ts);
125 
126 }  // namespace art
127 
128 #endif  // ART_LIBARTBASE_BASE_TIME_UTILS_H_
129