system-bus-radio/Using counter and threads/main.cpp

// SYSTEM BUS RADIO
// https://github.com/fulldecent/system-bus-radio
// Copyright 2016 William Entriken
// C++11 port by Ryou Ezoe

#include <iostream>
#include <iomanip>
#include <chrono>
#include <thread>
#include <atomic>
#include <mutex>
#include <condition_variable>

std::mutex m ;
std::condition_variable cv ;
std::chrono::high_resolution_clock::time_point mid ;
std::chrono::high_resolution_clock::time_point reset ;


void boost_song()
{
    using namespace std::chrono ;

    while( true )
    {
        std::unique_lock<std::mutex> lk{m} ;
        cv.wait( lk ) ;

        std::atomic<unsigned> x{0} ;
        while( high_resolution_clock::now() < mid )
        {
            ++x ;
        }
        std::this_thread::sleep_until( reset ) ;
    }
}

void square_am_signal(float time, float frequency)
{
    using namespace std::chrono ;
    
    std::cout << "Playing / " << time << " seconds / " << frequency << " Hz\n" ;

    seconds const sec{1} ;
    nanoseconds const nsec{ sec } ;
    using rep = nanoseconds::rep ;
    auto nsec_per_sec = nsec.count() ;

    nanoseconds const period( static_cast<rep>( nsec_per_sec / frequency) ) ;

    auto start = high_resolution_clock::now() ;
    auto const end = start + nanoseconds( static_cast<rep>(time * nsec_per_sec) ) ;

    while (high_resolution_clock::now() < end)
    {
        mid = start + period / 2 ;
        reset = start + period ;

        cv.notify_all() ;
        std::this_thread::sleep_until( reset ) ;
        start = reset;
    }
}

int main()
{

    for ( unsigned i = 0 ; i < std::thread::hardware_concurrency() ; ++i )
    {
        std::thread t( boost_song ) ;
        t.detach() ;
    }

    while (1)
    {
        square_am_signal(0.400, 2673);
        square_am_signal(0.400, 2349);
        square_am_signal(0.400, 2093);
        square_am_signal(0.400, 2349);
        square_am_signal(0.400, 2673);
        square_am_signal(0.400, 2673);
        square_am_signal(0.790, 2673);
        square_am_signal(0.400, 2349);
        square_am_signal(0.400, 2349);
        square_am_signal(0.790, 2349);
        square_am_signal(0.400, 2673);
        square_am_signal(0.400, 3136);
        square_am_signal(0.790, 3136);
        square_am_signal(0.400, 2673);
        square_am_signal(0.400, 2349);
        square_am_signal(0.400, 2093);
        square_am_signal(0.400, 2349);
        square_am_signal(0.400, 2673);
        square_am_signal(0.400, 2673);
        square_am_signal(0.400, 2673);
        square_am_signal(0.400, 2673);
        square_am_signal(0.400, 2349);
        square_am_signal(0.400, 2349);
        square_am_signal(0.400, 2673);
        square_am_signal(0.400, 2349);
        square_am_signal(0.790, 2093);
    }
}