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      1 /*
      2  * libjingle
      3  * Copyright 2008, Google Inc.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions are met:
      7  *
      8  *  1. Redistributions of source code must retain the above copyright notice,
      9  *     this list of conditions and the following disclaimer.
     10  *  2. Redistributions in binary form must reproduce the above copyright notice,
     11  *     this list of conditions and the following disclaimer in the documentation
     12  *     and/or other materials provided with the distribution.
     13  *  3. The name of the author may not be used to endorse or promote products
     14  *     derived from this software without specific prior written permission.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
     17  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     18  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
     19  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     20  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     21  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
     22  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
     23  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
     24  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
     25  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26  */
     27 
     28 #include "talk/base/timing.h"
     29 #include "talk/base/timeutils.h"
     30 
     31 #if defined(POSIX)
     32 #include <errno.h>
     33 #include <math.h>
     34 #include <sys/time.h>
     35 #if defined(OSX)
     36 #include <mach/mach.h>
     37 #include <mach/clock.h>
     38 #endif
     39 #elif defined(WIN32)
     40 #include <sys/timeb.h>
     41 #include "talk/base/win32.h"
     42 #endif
     43 
     44 namespace talk_base {
     45 
     46 Timing::Timing() {
     47 #if defined(WIN32)
     48   // This may fail, but we handle failure gracefully in the methods
     49   // that use it (use alternative sleep method).
     50   //
     51   // TODO: Make it possible for user to tell if IdleWait will
     52   // be done at lesser resolution because of this.
     53   timer_handle_ = CreateWaitableTimer(NULL,     // Security attributes.
     54                                       FALSE,    // Manual reset?
     55                                       NULL);    // Timer name.
     56 #endif
     57 }
     58 
     59 Timing::~Timing() {
     60 #if defined(WIN32)
     61   if (timer_handle_ != NULL)
     62     CloseHandle(timer_handle_);
     63 #endif
     64 }
     65 
     66 double Timing::WallTimeNow() {
     67 #if defined(POSIX)
     68   struct timeval time;
     69   gettimeofday(&time, NULL);
     70   // Convert from second (1.0) and microsecond (1e-6).
     71   return (static_cast<double>(time.tv_sec) +
     72           static_cast<double>(time.tv_usec) * 1.0e-6);
     73 
     74 #elif defined(WIN32)
     75   struct _timeb time;
     76   _ftime(&time);
     77   // Convert from second (1.0) and milliseconds (1e-3).
     78   return (static_cast<double>(time.time) +
     79           static_cast<double>(time.millitm) * 1.0e-3);
     80 #endif
     81 }
     82 
     83 double Timing::TimerNow() {
     84   return (static_cast<double>(TimeNanos()) / kNumNanosecsPerSec);
     85 }
     86 
     87 double Timing::BusyWait(double period) {
     88   double start_time = TimerNow();
     89   while (TimerNow() - start_time < period) {
     90   }
     91   return TimerNow() - start_time;
     92 }
     93 
     94 double Timing::IdleWait(double period) {
     95   double start_time = TimerNow();
     96 
     97 #if defined(POSIX)
     98   double sec_int, sec_frac = modf(period, &sec_int);
     99   struct timespec ts;
    100   ts.tv_sec = static_cast<time_t>(sec_int);
    101   ts.tv_nsec = static_cast<long>(sec_frac * 1.0e9);  // NOLINT
    102 
    103   // NOTE(liulk): for the NOLINT above, long is the appropriate POSIX
    104   // type.
    105 
    106   // POSIX nanosleep may be interrupted by signals.
    107   while (nanosleep(&ts, &ts) == -1 && errno == EINTR) {
    108   }
    109 
    110 #elif defined(WIN32)
    111   if (timer_handle_ != NULL) {
    112     LARGE_INTEGER due_time;
    113 
    114     // Negative indicates relative time.  The unit is 100 nanoseconds.
    115     due_time.QuadPart = -LONGLONG(period * 1.0e7);
    116 
    117     SetWaitableTimer(timer_handle_, &due_time, 0, NULL, NULL, TRUE);
    118     WaitForSingleObject(timer_handle_, INFINITE);
    119   } else {
    120     // Still attempts to sleep with lesser resolution.
    121     // The unit is in milliseconds.
    122     Sleep(DWORD(period * 1.0e3));
    123   }
    124 #endif
    125 
    126   return TimerNow() - start_time;
    127 }
    128 
    129 }  // namespace talk_base
    130