Timers.cpp revision c0a5e8df03d949cb307a0eb98f0222086c0434c1 
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#include <utils/Timers.h>
21#include <utils/Log.h>
22
23#include <stdlib.h>
24#include <stdio.h>
25#include <unistd.h>
26#include <sys/time.h>
27#include <time.h>
28#include <errno.h>
29#include <limits.h>
30
31#ifdef HAVE_WIN32_THREADS
32#include <windows.h>
33#endif
34
35nsecs_t systemTime(int clock)
36{
37#if defined(HAVE_POSIX_CLOCKS)
38    static const clockid_t clocks[] = {
39            CLOCK_REALTIME,
40            CLOCK_MONOTONIC,
41            CLOCK_PROCESS_CPUTIME_ID,
42            CLOCK_THREAD_CPUTIME_ID
43    };
44    struct timespec t;
45    t.tv_sec = t.tv_nsec = 0;
46    clock_gettime(clocks[clock], &t);
47    return nsecs_t(t.tv_sec)*1000000000LL + t.tv_nsec;
48#else
49    // we don't support the clocks here.
50    struct timeval t;
51    t.tv_sec = t.tv_usec = 0;
52    gettimeofday(&t, NULL);
53    return nsecs_t(t.tv_sec)*1000000000LL + nsecs_t(t.tv_usec)*1000LL;
54#endif
55}
56
57int toMillisecondTimeoutDelay(nsecs_t referenceTime, nsecs_t timeoutTime)
58{
59    int timeoutDelayMillis;
60    if (timeoutTime > referenceTime) {
61        uint64_t timeoutDelay = uint64_t(timeoutTime - referenceTime);
62        if (timeoutDelay > uint64_t((INT_MAX - 1) * 1000000LL)) {
63            timeoutDelayMillis = -1;
64        } else {
65            timeoutDelayMillis = (timeoutDelay + 999999LL) / 1000000LL;
66        }
67    } else {
68        timeoutDelayMillis = 0;
69    }
70    return timeoutDelayMillis;
71}
72
73
74/*
75 * ===========================================================================
76 *      DurationTimer
77 * ===========================================================================
78 */
79
80using namespace android;
81
82// Start the timer.
83void DurationTimer::start(void)
84{
85    gettimeofday(&mStartWhen, NULL);
86}
87
88// Stop the timer.
89void DurationTimer::stop(void)
90{
91    gettimeofday(&mStopWhen, NULL);
92}
93
94// Get the duration in microseconds.
95long long DurationTimer::durationUsecs(void) const
96{
97    return (long) subtractTimevals(&mStopWhen, &mStartWhen);
98}
99
100// Subtract two timevals.  Returns the difference (ptv1-ptv2) in
101// microseconds.
102/*static*/ long long DurationTimer::subtractTimevals(const struct timeval* ptv1,
103    const struct timeval* ptv2)
104{
105    long long stop  = ((long long) ptv1->tv_sec) * 1000000LL +
106                      ((long long) ptv1->tv_usec);
107    long long start = ((long long) ptv2->tv_sec) * 1000000LL +
108                      ((long long) ptv2->tv_usec);
109    return stop - start;
110}
111
112// Add the specified amount of time to the timeval.
113/*static*/ void DurationTimer::addToTimeval(struct timeval* ptv, long usec)
114{
115    if (usec < 0) {
116        LOG(LOG_WARN, "", "Negative values not supported in addToTimeval\n");
117        return;
118    }
119
120    // normalize tv_usec if necessary
121    if (ptv->tv_usec >= 1000000) {
122        ptv->tv_sec += ptv->tv_usec / 1000000;
123        ptv->tv_usec %= 1000000;
124    }
125
126    ptv->tv_usec += usec % 1000000;
127    if (ptv->tv_usec >= 1000000) {
128        ptv->tv_usec -= 1000000;
129        ptv->tv_sec++;
130    }
131    ptv->tv_sec += usec / 1000000;
132}
133
134