X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=common%2Futility%2Ftimer.h;h=ce399327572e9190ef87d6dfbe27e56523bb2adc;hb=f9c7bf3eee1eefc10e11d8d760d627c70a8d111f;hp=574391682d057b98d3ea59b3d66a07268721583e;hpb=69c89fd3ef41155fb4502091f4b3a68490cafda8;p=casparcg

diff --git a/common/utility/timer.h b/common/utility/timer.h
index 574391682..ce3993275 100644
--- a/common/utility/timer.h
+++ b/common/utility/timer.h
@@ -1,26 +1,84 @@
+/*
+* copyright (c) 2010 Sveriges Television AB <info@casparcg.com>
+*
+*  This file is part of CasparCG.
+*
+*    CasparCG is free software: you can redistribute it and/or modify
+*    it under the terms of the GNU General Public License as published by
+*    the Free Software Foundation, either version 3 of the License, or
+*    (at your option) any later version.
+*
+*    CasparCG is distributed in the hope that it will be useful,
+*    but WITHOUT ANY WARRANTY; without even the implied warranty of
+*    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+*    GNU General Public License for more details.
+
+*    You should have received a copy of the GNU General Public License
+*    along with CasparCG.  If not, see <http://www.gnu.org/licenses/>.
+*
+*/
 #pragma once
 
+#define NOMINMAX
+
 #include <windows.h>
+#include <Mmsystem.h>
 
 namespace caspar {
 	
-class timer
+class high_prec_timer
 {
 public:
-	timer() : time_(timeGetTime()){}
-
-	double elapsed()
+	high_prec_timer()
+		: time_(0)
 	{
-		return static_cast<double>(timeGetTime() - time_)/1000.0;
 	}
-	
-	void reset()
-	{
-		time_ = timeGetTime();
-	}
-	
+
+	// Author: Ryan M. Geiss
+	// http://www.geisswerks.com/ryan/FAQS/timing.html
+	void tick(double interval)
+	{     	
+		auto t = ::timeGetTime();
+
+		if (time_ != 0)
+		{
+			auto ticks_to_wait = static_cast<DWORD>(interval*1000.0);
+			bool done = 0;
+			do
+			{				
+				auto ticks_passed = t - time_;
+				auto ticks_left	  = ticks_to_wait - ticks_passed;
+
+				if (t < time_)    // time wrap
+					done = 1;
+				if (ticks_passed >= ticks_to_wait)
+					done = 1;
+				
+				if (!done)
+				{
+					// if > 0.002s left, do Sleep(1), which will actually sleep some 
+					//   steady amount, probably 1-2 ms,
+					//   and do so in a nice way (cpu meter drops; laptop battery spared).
+					// otherwise, do a few Sleep(0)'s, which just give up the timeslice,
+					//   but don't really save cpu or battery, but do pass a tiny
+					//   amount of time.
+					if (ticks_left > 2)
+						Sleep(1);
+					else                        
+						for (int i = 0; i < 10; ++i) 
+							Sleep(0);  // causes thread to give up its timeslice
+				}
+
+				t = ::timeGetTime();
+			}
+			while (!done);            
+		}
+
+		time_ = t;
+	}		
 private:	
 	DWORD time_;
 };
 
+
 }
\ No newline at end of file