CTicTac.cpp

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          http://www.mrpt.org/                          |
   |                                                                        |
   | Copyright (c) 2005-2018, Individual contributors, see AUTHORS file     |
   | See: http://www.mrpt.org/Authors - All rights reserved.                |
   | Released under BSD License. See details in http://www.mrpt.org/License |
   +------------------------------------------------------------------------+ */
 
#include "system-precomp.h"  // Precompiled headers
 
#ifdef _WIN32
#include <windows.h>
#else
#include <sys/time.h>
#endif
 
#include <mrpt/core/exceptions.h>
#include <mrpt/system/CTicTac.h>
#include <cstring>
#include <cassert>
 
#include <type_traits>
static_assert(
        !std::is_copy_constructible<mrpt::system::CTicTac>::value &&
                !std::is_copy_assignable<mrpt::system::CTicTac>::value,
        "Copy Check");
 
// For Windows: get the common code out of CTicTac so it's only run once!
#ifdef _WIN32
struct AuxWindowsTicTac
{
        static AuxWindowsTicTac& GetInstance() noexcept
        {
                static AuxWindowsTicTac obj;
                return obj;
        }
 
        double dbl_period;
 
   private:
        LARGE_INTEGER m_freq;
 
        AuxWindowsTicTac() noexcept : dbl_period(.0)
        {
                QueryPerformanceFrequency(&m_freq);
                assert(m_freq.QuadPart != 0);
                dbl_period = 1.0 / static_cast<double>(m_freq.QuadPart);
        }
};
 
#endif
 
using namespace mrpt::system;
 
// Macros for easy access to memory with the correct types:
#ifdef _WIN32
#define LARGE_INTEGER_NUMS reinterpret_cast<LARGE_INTEGER*>(largeInts)
#else
#define TIMEVAL_NUMS reinterpret_cast<struct timeval*>(largeInts)
#endif
 
CTicTac::CTicTac() noexcept
{
        ::memset(largeInts, 0, sizeof(largeInts));
 
#ifdef _WIN32
        static_assert(
                sizeof(largeInts) >= 2 * sizeof(LARGE_INTEGER),
                "sizeof(LARGE_INTEGER) failed!");
#else
        static_assert(
                sizeof(largeInts) >= 2 * sizeof(struct timeval),
                "sizeof(struct timeval) failed!");
#endif
        Tic();
}
 
void CTicTac::Tic() noexcept
{
#ifdef _WIN32
        LARGE_INTEGER* l = LARGE_INTEGER_NUMS;
        QueryPerformanceCounter(&l[0]);
#else
        struct timeval* ts = TIMEVAL_NUMS;
        gettimeofday(&ts[0], nullptr);
#endif
}
 
double CTicTac::Tac() noexcept
{
#ifdef _WIN32
        LARGE_INTEGER* l = LARGE_INTEGER_NUMS;
        QueryPerformanceCounter(&l[1]);
        return (l[1].QuadPart - l[0].QuadPart) *
                   AuxWindowsTicTac::GetInstance().dbl_period;
#else
        struct timeval* ts = TIMEVAL_NUMS;
        gettimeofday(&ts[1], nullptr);
        return (ts[1].tv_sec - ts[0].tv_sec) +
                   1e-6 * (ts[1].tv_usec - ts[0].tv_usec);
#endif
}