git.sesse.net Git - casparcg/blob - common/utility/timer.h

   1 #pragma once\r
   2 \r
   3 #include <windows.h>\r
   4 \r
   5 namespace caspar {\r
   6         \r
   7 class timer\r
   8 {\r
   9 public:\r
  10         timer() : time_(timeGetTime()){}\r
  11 \r
  12         double elapsed()\r
  13         {\r
  14                 return static_cast<double>(timeGetTime() - time_)/1000.0;\r
  15         }\r
  16         \r
  17         void reset()\r
  18         {\r
  19                 time_ = timeGetTime();\r
  20         }\r
  21         \r
  22 private:        \r
  23         DWORD time_;\r
  24 };\r
  25 \r
  26 class high_prec_timer\r
  27 {\r
  28 public:\r
  29         high_prec_timer()\r
  30         {\r
  31                 QueryPerformanceFrequency(&freq_);\r
  32                 QueryPerformanceCounter(&time_);\r
  33         }\r
  34 \r
  35         // Author: Ryan M. Geiss\r
  36         // http://www.geisswerks.com/ryan/FAQS/timing.html\r
  37         void tick(double interval)\r
  38         {       \r
  39                 LARGE_INTEGER t;\r
  40                 QueryPerformanceCounter(&t);\r
  41 \r
  42                 if (time_.QuadPart != 0)\r
  43                 {\r
  44                         int ticks_to_wait = static_cast<int>(static_cast<double>(freq_.QuadPart) * interval);\r
  45                         int done = 0;\r
  46                         do\r
  47                         {\r
  48                                 QueryPerformanceCounter(&t);\r
  49                                 \r
  50                                 int ticks_passed = static_cast<int>(static_cast<__int64>(t.QuadPart) - static_cast<__int64>(time_.QuadPart));\r
  51                                 int ticks_left = ticks_to_wait - ticks_passed;\r
  52 \r
  53                                 if (t.QuadPart < time_.QuadPart)    // time wrap\r
  54                                         done = 1;\r
  55                                 if (ticks_passed >= ticks_to_wait)\r
  56                                         done = 1;\r
  57                                 \r
  58                                 if (!done)\r
  59                                 {\r
  60                                         // if > 0.002s left, do Sleep(1), which will actually sleep some \r
  61                                         //   steady amount, probably 1-2 ms,\r
  62                                         //   and do so in a nice way (cpu meter drops; laptop battery spared).\r
  63                                         // otherwise, do a few Sleep(0)'s, which just give up the timeslice,\r
  64                                         //   but don't really save cpu or battery, but do pass a tiny\r
  65                                         //   amount of time.\r
  66                                         if (ticks_left > static_cast<int>((freq_.QuadPart*2)/1000))\r
  67                                                 Sleep(1);\r
  68                                         else                        \r
  69                                                 for (int i = 0; i < 10; ++i) \r
  70                                                         Sleep(0);  // causes thread to give up its timeslice\r
  71                                 }\r
  72                         }\r
  73                         while (!done);            \r
  74                 }\r
  75 \r
  76                 time_ = t;\r
  77         }               \r
  78 private:        \r
  79         LARGE_INTEGER freq_;\r
  80         LARGE_INTEGER time_;\r
  81 };\r
  82 \r
  83 \r
  84 }