Add initial prototype.

3-mid/physics/implement/box2d/contrib/src/common/b2_timer.cpp

@@ -0,0 +1,125 @@
+// MIT License
+
+// Copyright (c) 2019 Erin Catto
+
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+#include "box2d/b2_timer.h"
+
+#if defined(_WIN32)
+
+double b2Timer::s_invFrequency = 0.0;
+
+#ifndef WIN32_LEAN_AND_MEAN
+#define WIN32_LEAN_AND_MEAN
+#endif
+
+#include <windows.h>
+
+b2Timer::b2Timer()
+{
+	LARGE_INTEGER largeInteger;
+
+	if (s_invFrequency == 0.0)
+	{
+		QueryPerformanceFrequency(&largeInteger);
+		s_invFrequency = double(largeInteger.QuadPart);
+		if (s_invFrequency > 0.0)
+		{
+			s_invFrequency = 1000.0 / s_invFrequency;
+		}
+	}
+
+	QueryPerformanceCounter(&largeInteger);
+	m_start = double(largeInteger.QuadPart);
+}
+
+void b2Timer::Reset()
+{
+	LARGE_INTEGER largeInteger;
+	QueryPerformanceCounter(&largeInteger);
+	m_start = double(largeInteger.QuadPart);
+}
+
+float b2Timer::GetMilliseconds() const
+{
+	LARGE_INTEGER largeInteger;
+	QueryPerformanceCounter(&largeInteger);
+	double count = double(largeInteger.QuadPart);
+	float ms = float(s_invFrequency * (count - m_start));
+	return ms;
+}
+
+#elif defined(__linux__) || defined (__APPLE__)
+
+#include <sys/time.h>
+
+b2Timer::b2Timer()
+{
+    Reset();
+}
+
+void b2Timer::Reset()
+{
+    timeval t;
+    gettimeofday(&t, 0);
+    m_start_sec = t.tv_sec;
+    m_start_usec = t.tv_usec;
+}
+
+float b2Timer::GetMilliseconds() const
+{
+    timeval t;
+    gettimeofday(&t, 0);
+	time_t start_sec = m_start_sec;
+	suseconds_t start_usec = m_start_usec;
+	
+	// http://www.gnu.org/software/libc/manual/html_node/Elapsed-Time.html
+	if (t.tv_usec < start_usec)
+	{
+		int nsec = (start_usec - t.tv_usec) / 1000000 + 1;
+		start_usec -= 1000000 * nsec;
+		start_sec += nsec;
+	}
+	
+	if (t.tv_usec - start_usec > 1000000)
+	{
+		int nsec = (t.tv_usec - start_usec) / 1000000;
+		start_usec += 1000000 * nsec;
+		start_sec -= nsec;
+	}
+	return 1000.0f * (t.tv_sec - start_sec) + 0.001f * (t.tv_usec - start_usec);
+}
+
+#else
+
+b2Timer::b2Timer()
+{
+}
+
+void b2Timer::Reset()
+{
+}
+
+float b2Timer::GetMilliseconds() const
+{
+	return 0.0f;
+}
+
+#endif