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/* 
 * Author: Massimo Torquati <torquati@di.unipi.it> 
 * Date:   November 2014
 */
//
// Toy example to test FastFlow pipeline. 
// It finds the first n prime numbers using a pipeline of n stages.
// Please remember that in FastFlow pipeline stages are threads !
//  Example:
//    pipe_primes 16
//
//     generator  ---> stage(2) ---> stage(3) ---> stage(4)
//        ^                                           |
//        |___________________________________________|
//
//  -   The number of stages is floor(sqrt(n)) plus the generator.
//  -   stage(i) sends out only those numbers x such that (x != i and (x % i) != 0)
//  -   generators first generates all numbers, then prints all primes received
//                  in input from the last stage.
//

#include <cmath>
#include <iostream>
#include <vector>
#include <ff/pipeline.hpp>
using namespace ff;

// stream generator
struct generator: ff_node {
    generator(long n):n(n) {}
    void *svc(void *x) {
        if (x == nullptr) {   // first time 
            for(long x=2;x<=n;++x) ff_send_out((void*)x);
            ff_send_out(EOS);
            return GO_ON;
        }
        std::cout << reinterpret_cast<long>(x) << " ";
        return GO_ON;
    }
    long n;
};
// generic stage
struct stage: ff_node_t<long> {    
    int svc_init() { myid = get_my_id() + 1 ; return 0; }
    long *svc(long *t) {
        long x = (long)t;
        if (x == myid) return t;
        if (x % myid)  return t;
        return GO_ON;
    }
    long myid;
};

int main(int argc, char *argv[]) {    
    if (argc<2) {
        std::cerr << "use: " << argv[0]  << " number (not too big !)\n";
        return -1;
    }
    long n = atol(argv[1]);
    assert(n>1);
    
    // The number of stages (i.e. threads) is floor(sqrt(n))+1 ||
    
    ff_pipe<long> pipe(new generator(n));
    long sq = sqrt(n);
    for(long i=2;i<=sq;++i) pipe.add_stage(new stage);
    pipe.cleanup_nodes();
    pipe.wrap_around();
    pipe.run_and_wait_end();
    std::cout << "\n\n";
    return 0;
}