/** \file
    \brief Siamese FEC Implementation: Tools
    \copyright Copyright (c) 2017 Christopher A. Taylor.  All rights reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are met:

    * Redistributions of source code must retain the above copyright notice,
      this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright notice,
      this list of conditions and the following disclaimer in the documentation
      and/or other materials provided with the distribution.
    * Neither the name of Siamese nor the names of its contributors may be
      used to endorse or promote products derived from this software without
      specific prior written permission.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
    AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
    ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
    LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
    CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
    SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
    INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
    CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
    ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
    POSSIBILITY OF SUCH DAMAGE.
*/

#include "SiameseTools.h"

#ifdef _WIN32
    #ifndef NOMINMAX
        #define NOMINMAX
    #endif
    #include <windows.h>
#elif __MACH__
    #include <mach/mach_time.h>
    #include <mach/mach.h>
    #include <mach/clock.h>

    extern mach_port_t clock_port;
#else
    #include <time.h>
    #include <sys/time.h>
#endif

namespace siamese {


//------------------------------------------------------------------------------
// Timing

#ifdef _WIN32
// Precomputed frequency inverse
static double PerfFrequencyInverseUsec = 0.;
static double PerfFrequencyInverseMsec = 0.;

static void InitPerfFrequencyInverse()
{
    LARGE_INTEGER freq = {};
    if (!::QueryPerformanceFrequency(&freq) || freq.QuadPart == 0)
        return;
    const double invFreq = 1. / (double)freq.QuadPart;
    PerfFrequencyInverseUsec = 1000000. * invFreq;
    PerfFrequencyInverseMsec = 1000. * invFreq;
    SIAMESE_DEBUG_ASSERT(PerfFrequencyInverseUsec > 0.);
    SIAMESE_DEBUG_ASSERT(PerfFrequencyInverseMsec > 0.);
}
#elif __MACH__
static bool m_clock_serv_init = false;
static clock_serv_t m_clock_serv = 0;

static void InitClockServ()
{
    m_clock_serv_init = true;
    host_get_clock_service(mach_host_self(), SYSTEM_CLOCK, &m_clock_serv);
}
#endif // _WIN32

uint64_t GetTimeUsec()
{
#ifdef _WIN32
    LARGE_INTEGER timeStamp = {};
    if (!::QueryPerformanceCounter(&timeStamp))
        return 0;
    if (PerfFrequencyInverseUsec == 0.)
        InitPerfFrequencyInverse();
    return (uint64_t)(PerfFrequencyInverseUsec * timeStamp.QuadPart);
#elif __MACH__
    if (!m_clock_serv_init)
        InitClockServ();

    mach_timespec_t tv;
    clock_get_time(m_clock_serv, &tv);

    return 1000000 * tv.tv_sec + tv.tv_nsec / 1000;
#else
    struct timeval tv;
    gettimeofday(&tv, nullptr);
    return 1000000 * tv.tv_sec + tv.tv_usec;
#endif
}

uint64_t GetTimeMsec()
{
#ifdef _WIN32
    LARGE_INTEGER timeStamp = {};
    if (!::QueryPerformanceCounter(&timeStamp))
        return 0;
    if (PerfFrequencyInverseMsec == 0.)
        InitPerfFrequencyInverse();
    return (uint64_t)(PerfFrequencyInverseMsec * timeStamp.QuadPart);
#else
    // TBD: Optimize this?
    return GetTimeUsec() / 1000;
#endif
}


} // namespace siamese