//
//  main.mm
//  dispatch_test
//
//  Created by Antony Searle on 20/9/19.
//  Copyright © 2019 Antony Searle. All rights reserved.
//

#import <Foundation/Foundation.h>

#include <atomic>
#include <thread>

int main(int argc, const char * argv[]) {
    // std::atomic<long> x(0);
    auto N = 1000;
    auto M = 100'000'000;
    auto active = new std::atomic<long>(0);
    auto barrier = new std::atomic<long>(N);
    printf("concurrency %u\n", std::thread::hardware_concurrency());
    auto q = dispatch_get_global_queue(QOS_CLASS_DEFAULT, 0);
    @autoreleasepool {
        for (long i = 0; i != N; ++i) {
            // auto q = dispatch_queue_create(nullptr, DISPATCH_QUEUE_CONCURRENT);
            // auto q = dispatch_queue_create(nullptr, DISPATCH_QUEUE_SERIAL);
            dispatch_async(q, ^{
                long z = active->fetch_add(1, std::memory_order_acq_rel);
                // std::this_thread::sleep_for(std::chrono::seconds(1));
                for (auto j = 0; j != M; ++j) // do some work
                    z *= z;
                printf("%ld\t%ld/%ld\n", active->fetch_sub(1, std::memory_order_acq_rel), i, z);
                if (barrier->fetch_sub(1, std::memory_order_acq_rel) == 1)
                    exit(EXIT_SUCCESS);
            });
            printf("submitted block %ld\n", i);
        }
        dispatch_main();
    }
    return 0;
}