Timers.h revision 1eb42cf6dbe457a5173193eb0276f8c703003db5 
1/*
2 * Copyright (C) 2005 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//
18// Timer functions.
19//
20#ifndef _LIBS_UTILS_TIMERS_H
21#define _LIBS_UTILS_TIMERS_H
22
23#include <stdint.h>
24#include <sys/types.h>
25#include <sys/time.h>
26
27// ------------------------------------------------------------------
28// C API
29
30#ifdef __cplusplus
31extern "C" {
32#endif
33
34typedef int64_t nsecs_t;       // nano-seconds
35
36static inline nsecs_t seconds_to_nanoseconds(nsecs_t secs)
37{
38    return secs*1000000000;
39}
40
41static inline nsecs_t milliseconds_to_nanoseconds(nsecs_t secs)
42{
43    return secs*1000000;
44}
45
46static inline nsecs_t microseconds_to_nanoseconds(nsecs_t secs)
47{
48    return secs*1000;
49}
50
51static inline nsecs_t nanoseconds_to_seconds(nsecs_t secs)
52{
53    return secs/1000000000;
54}
55
56static inline nsecs_t nanoseconds_to_milliseconds(nsecs_t secs)
57{
58    return secs/1000000;
59}
60
61static inline nsecs_t nanoseconds_to_microseconds(nsecs_t secs)
62{
63    return secs/1000;
64}
65
66static inline nsecs_t s2ns(nsecs_t v)  {return seconds_to_nanoseconds(v);}
67static inline nsecs_t ms2ns(nsecs_t v) {return milliseconds_to_nanoseconds(v);}
68static inline nsecs_t us2ns(nsecs_t v) {return microseconds_to_nanoseconds(v);}
69static inline nsecs_t ns2s(nsecs_t v)  {return nanoseconds_to_seconds(v);}
70static inline nsecs_t ns2ms(nsecs_t v) {return nanoseconds_to_milliseconds(v);}
71static inline nsecs_t ns2us(nsecs_t v) {return nanoseconds_to_microseconds(v);}
72
73static inline nsecs_t seconds(nsecs_t v)      { return s2ns(v); }
74static inline nsecs_t milliseconds(nsecs_t v) { return ms2ns(v); }
75static inline nsecs_t microseconds(nsecs_t v) { return us2ns(v); }
76
77enum {
78    SYSTEM_TIME_REALTIME = 0,  // system-wide realtime clock
79    SYSTEM_TIME_MONOTONIC = 1, // monotonic time since unspecified starting point
80    SYSTEM_TIME_PROCESS = 2,   // high-resolution per-process clock
81    SYSTEM_TIME_THREAD = 3     // high-resolution per-thread clock
82};
83
84// return the system-time according to the specified clock
85#ifdef __cplusplus
86nsecs_t systemTime(int clock = SYSTEM_TIME_MONOTONIC);
87#else
88nsecs_t systemTime(int clock);
89#endif // def __cplusplus
90
91/**
92 * Returns the number of milliseconds to wait between the reference time and the timeout time.
93 * If the timeout is in the past relative to the reference time, returns 0.
94 * If the timeout is more than INT_MAX milliseconds in the future relative to the reference time,
95 * such as when timeoutTime == LLONG_MAX, returns -1 to indicate an infinite timeout delay.
96 * Otherwise, returns the difference between the reference time and timeout time
97 * rounded up to the next millisecond.
98 */
99int toMillisecondTimeoutDelay(nsecs_t referenceTime, nsecs_t timeoutTime);
100
101#ifdef __cplusplus
102} // extern "C"
103#endif
104
105// ------------------------------------------------------------------
106// C++ API
107
108#ifdef __cplusplus
109
110namespace android {
111/*
112 * Time the duration of something.
113 *
114 * Includes some timeval manipulation functions.
115 */
116class DurationTimer {
117public:
118    DurationTimer() {}
119    ~DurationTimer() {}
120
121    // Start the timer.
122    void start();
123    // Stop the timer.
124    void stop();
125    // Get the duration in microseconds.
126    long long durationUsecs() const;
127
128    // Subtract two timevals.  Returns the difference (ptv1-ptv2) in
129    // microseconds.
130    static long long subtractTimevals(const struct timeval* ptv1,
131        const struct timeval* ptv2);
132
133    // Add the specified amount of time to the timeval.
134    static void addToTimeval(struct timeval* ptv, long usec);
135
136private:
137    struct timeval  mStartWhen;
138    struct timeval  mStopWhen;
139};
140
141}; // android
142#endif // def __cplusplus
143
144#endif // _LIBS_UTILS_TIMERS_H
145