2 * copyright (c) 2010 Sveriges Television AB <info@casparcg.com>
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4 * This file is part of CasparCG.
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6 * CasparCG is free software: you can redistribute it and/or modify
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7 * it under the terms of the GNU General Public License as published by
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8 * the Free Software Foundation, either version 3 of the License, or
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9 * (at your option) any later version.
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11 * CasparCG is distributed in the hope that it will be useful,
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12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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14 * GNU General Public License for more details.
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16 * You should have received a copy of the GNU General Public License
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17 * along with CasparCG. If not, see <http://www.gnu.org/licenses/>.
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24 #include <windows.h>
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25 #include <Mmsystem.h>
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29 class high_prec_timer
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37 // Author: Ryan M. Geiss
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38 // http://www.geisswerks.com/ryan/FAQS/timing.html
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39 void tick(double interval)
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41 auto t = ::timeGetTime();
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45 auto ticks_to_wait = static_cast<DWORD>(interval*1000.0);
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49 auto ticks_passed = t - time_;
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50 auto ticks_left = ticks_to_wait - ticks_passed;
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52 if (t < time_) // time wrap
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54 if (ticks_passed >= ticks_to_wait)
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59 // if > 0.002s left, do Sleep(1), which will actually sleep some
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60 // steady amount, probably 1-2 ms,
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61 // and do so in a nice way (cpu meter drops; laptop battery spared).
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62 // otherwise, do a few Sleep(0)'s, which just give up the timeslice,
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63 // but don't really save cpu or battery, but do pass a tiny
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68 for (int i = 0; i < 10; ++i)
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69 Sleep(0); // causes thread to give up its timeslice
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72 t = ::timeGetTime();
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