Use chrono to simplify timer

library/LibUtilities/BasicUtils/Timer.cpp

@@ -37,91 +37,35 @@
 
 namespace Nektar
 {
-    Timer::Timer() :
-        m_start(),
-        m_end(),
-        m_resolution()
-    {
-    }
 
-    Timer::~Timer()
-    {
-    }
-
-    void Timer::Start()
-    {
-        #ifdef _WIN32
-            QueryPerformanceCounter(&m_start);
-        #elif defined(__APPLE__)
-            gettimeofday(&m_start, 0);
-        #else 
-            clock_gettime(CLOCK_REALTIME, &m_start);
-        #endif
-    }
+Timer::Timer() :
+    m_start(),
+    m_end()
+{
+}
 
-    void Timer::Stop()
-    {
-        #ifdef _WIN32
-            QueryPerformanceCounter(&m_end);
-        #elif defined(__APPLE__)
-            gettimeofday(&m_end, 0);
-        #else 
-            clock_gettime(CLOCK_REALTIME, &m_end);
-        #endif
-    }
+Timer::~Timer()
+{
+}
 
-    Timer::CounterType Timer::Elapsed()
-    {
-        #ifdef _WIN32
-            CounterType result;
-            result.QuadPart = m_end.QuadPart - m_start.QuadPart;
-            return result;
-        #elif defined(__APPLE__)
-            CounterType result = m_end;
-            
-            if( result.tv_usec < m_start.tv_usec) 
-            {
-                result.tv_sec -= 1;
-                result.tv_usec += 1000000;
-            }
-            
-            result.tv_sec -= m_start.tv_sec;
-            result.tv_usec -= m_start.tv_usec;
-            
-            return result;
-        #else
-            CounterType result = m_end;
+void Timer::Start()
+{
+    m_start = Clock::now();
+}
 
-            if( result.tv_nsec < m_start.tv_nsec) 
-            {
-                result.tv_sec -= 1;
-                result.tv_nsec += 1000000000;
-            }
-            
-            result.tv_sec -= m_start.tv_sec;
-            result.tv_nsec -= m_start.tv_nsec;
+void Timer::Stop()
+{
+    m_end = Clock::now();
+}
 
-            return result;
-        #endif
-    }
+Timer::Seconds Timer::Elapsed()
+{
+    return std::chrono::duration_cast<Seconds>(m_end - m_start);
+}
 
-    NekDouble Timer::TimePerTest(unsigned int n)
-    {
-        #ifdef _WIN32
-            CounterType frequency;
-            QueryPerformanceFrequency(&frequency);
-            return Elapsed().QuadPart/static_cast<NekDouble>(n) * 1.0/frequency.QuadPart;
-        #elif defined(__APPLE__)
-            CounterType elapsed = Elapsed();
-            NekDouble result = elapsed.tv_sec/static_cast<NekDouble>(n) +
-                ( elapsed.tv_usec/static_cast<NekDouble>(n) * 1.0e-6);
-            return result;
-        #else
-            CounterType elapsed = Elapsed();
-            NekDouble result = elapsed.tv_sec/static_cast<NekDouble>(n) +
-                ( elapsed.tv_nsec/static_cast<NekDouble>(n) * 1.0e-9);
-            return result;
-        #endif
-    }
+NekDouble Timer::TimePerTest(unsigned int n)
+{
+    return Elapsed().count() / static_cast<NekDouble>(n);
+}
 
-}     
+}

library/LibUtilities/BasicUtils/Timer.h

@@ -37,50 +37,41 @@
 #ifndef NEKTAR_LIB_UTILITIES_BASIC_UTILS_TIMER_H
 #define NEKTAR_LIB_UTILITIES_BASIC_UTILS_TIMER_H
 
-#ifdef _WIN32
-#define NOMINMAX
-#include <windows.h>
-#else
-#include <sys/time.h>
-#include <time.h>
-#endif
+#include <chrono>
 
 #include <LibUtilities/LibUtilitiesDeclspec.h>
 #include <LibUtilities/BasicConst/NektarUnivConsts.hpp>
 
 namespace Nektar
 {
-    class Timer
-    {    
-        public:
-            #ifdef _WIN32
-                typedef LARGE_INTEGER CounterType;
-            #elif  defined(__APPLE__)
-                typedef timeval CounterType;
-            #else
-                typedef timespec CounterType;
-            #endif
 
-        public:
-            LIB_UTILITIES_EXPORT Timer();
-            LIB_UTILITIES_EXPORT ~Timer();
+class Timer
+{
+    public:
+        using Clock       = std::chrono::steady_clock;
+        using CounterType = Clock::time_point;
+        using Seconds     = std::chrono::duration<NekDouble>;
+
+    public:
+        LIB_UTILITIES_EXPORT Timer();
+        LIB_UTILITIES_EXPORT ~Timer();
+
+        Timer(const Timer& rhs) = delete;
+        Timer& operator=(const Timer& rhs) = delete;
 
-            LIB_UTILITIES_EXPORT void Start();
-            LIB_UTILITIES_EXPORT void Stop();
-            LIB_UTILITIES_EXPORT CounterType Elapsed();
+        LIB_UTILITIES_EXPORT void Start();
+        LIB_UTILITIES_EXPORT void Stop();
+        LIB_UTILITIES_EXPORT Seconds Elapsed();
 
-            /// \brief Returns amount of seconds per iteration in
-            ///        a test with n iterations.
-            LIB_UTILITIES_EXPORT NekDouble TimePerTest(unsigned int n);
+        /// \brief Returns amount of seconds per iteration in
+        ///        a test with n iterations.
+        LIB_UTILITIES_EXPORT NekDouble TimePerTest(unsigned int n);
 
-        private:
-            Timer(const Timer& rhs);
-            Timer& operator=(const Timer& rhs);
+    private:
+        CounterType m_start;
+        CounterType m_end;
+};
 
-            CounterType m_start;
-            CounterType m_end;
-            CounterType m_resolution;
-    };
 }
 
 #endif //NEKTAR_LIB_UTILITIES_BASIC_UTILS_TIMER_H