tickconverter.cpp

// #################################################################################################
//  ALib C++ Library
//
//  Copyright 2013-2025 A-Worx GmbH, Germany
//  Published under 'Boost Software License' (a free software license, see LICENSE.txt)
// #################################################################################################
#include "alib_precompile.hpp"
#if !defined(ALIB_C20_MODULES) || ((ALIB_C20_MODULES != 0) && (ALIB_C20_MODULES != 1))
#   error "Symbol ALIB_C20_MODULES has to be given to the compiler as either 0 or 1"
#endif
#if ALIB_C20_MODULES
    module;
#endif
// ======================================   Global Fragment   ======================================
#include "alib/alib.inl"
// ===========================================   Module   ==========================================
#if ALIB_C20_MODULES
    module ALib.Time;
#else
#   include "ALib.Time.H"
#endif
// ======================================   Implementation   =======================================
using namespace std::chrono;
namespace alib::time {
 
 
#   include "ALib.Lang.CIMethods.H"
 
// #################################################################################################
// TickConverter
// #################################################################################################
void TickConverter::SyncClocks( int qtyRepeats )
{
    Ticks::TTimePoint       steadyClock;
    DateTime::TTimePoint    systemClock;
    uint64_t lastDiff= 0;
    for( int i= 0 ; i < qtyRepeats ; ++i )
    {
        systemClock= system_clock::now();
        steadyClock= steady_clock::now();
 
        auto systemCount= systemClock.time_since_epoch().count();
        auto steadyCount= steadyClock.time_since_epoch().count();
 
        // This cannot be optimized, because:
        // a) we have to use an unsigned integer, and
        // b) we have to take into account which clock was measured first and which last. If
        //    interrupted between the calls, the difference either shrinks or increases.
        if( systemCount < steadyCount )
        {
            uint64_t diff= uint64_t( steadyCount - systemCount );
            if( lastDiff == 0 || diff < lastDiff )
            {
                steadyClockSyncTime= steadyClock;
                systemClockSyncTime= systemClock;
                lastDiff= diff;
            }
        }
        else
        {
            uint64_t diff= uint64_t( systemCount - steadyCount  );
            if( lastDiff == 0 || diff > lastDiff )
            {
                steadyClockSyncTime= steadyClock;
                systemClockSyncTime= systemClock;
                lastDiff= diff;
            }
        }
    }
}
 
} // namespace [alib::time]