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      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
     31 extern "C" {
     32 #endif
     33 
     34 typedef int64_t nsecs_t;       // nano-seconds
     35 
     36 static inline nsecs_t seconds_to_nanoseconds(nsecs_t secs)
     37 {
     38     return secs*1000000000;
     39 }
     40 
     41 static inline nsecs_t milliseconds_to_nanoseconds(nsecs_t secs)
     42 {
     43     return secs*1000000;
     44 }
     45 
     46 static inline nsecs_t microseconds_to_nanoseconds(nsecs_t secs)
     47 {
     48     return secs*1000;
     49 }
     50 
     51 static inline nsecs_t nanoseconds_to_seconds(nsecs_t secs)
     52 {
     53     return secs/1000000000;
     54 }
     55 
     56 static inline nsecs_t nanoseconds_to_milliseconds(nsecs_t secs)
     57 {
     58     return secs/1000000;
     59 }
     60 
     61 static inline nsecs_t nanoseconds_to_microseconds(nsecs_t secs)
     62 {
     63     return secs/1000;
     64 }
     65 
     66 static inline nsecs_t s2ns(nsecs_t v)  {return seconds_to_nanoseconds(v);}
     67 static inline nsecs_t ms2ns(nsecs_t v) {return milliseconds_to_nanoseconds(v);}
     68 static inline nsecs_t us2ns(nsecs_t v) {return microseconds_to_nanoseconds(v);}
     69 static inline nsecs_t ns2s(nsecs_t v)  {return nanoseconds_to_seconds(v);}
     70 static inline nsecs_t ns2ms(nsecs_t v) {return nanoseconds_to_milliseconds(v);}
     71 static inline nsecs_t ns2us(nsecs_t v) {return nanoseconds_to_microseconds(v);}
     72 
     73 static inline nsecs_t seconds(nsecs_t v)      { return s2ns(v); }
     74 static inline nsecs_t milliseconds(nsecs_t v) { return ms2ns(v); }
     75 static inline nsecs_t microseconds(nsecs_t v) { return us2ns(v); }
     76 
     77 enum {
     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
     86 nsecs_t systemTime(int clock = SYSTEM_TIME_MONOTONIC);
     87 #else
     88 nsecs_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  */
     99 int 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 
    110 namespace android {
    111 /*
    112  * Time the duration of something.
    113  *
    114  * Includes some timeval manipulation functions.
    115  */
    116 class DurationTimer {
    117 public:
    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 
    136 private:
    137     struct timeval  mStartWhen;
    138     struct timeval  mStopWhen;
    139 };
    140 
    141 }; // android
    142 #endif // def __cplusplus
    143 
    144 #endif // _LIBS_UTILS_TIMERS_H
    145