#include <iostream>
#include <queue>
#include <pthread.h>

using namespace std; 

class Task {
private: 
  int n; 
  float * v;
 
public: 
  Task(int n, float * v):n(n),v(v) {}

  float * get() {
    return v;
  }

  int length() {
    return n; 
  }
};

template <class Task> class Queue {
private: 
  std::queue<Task> tasks;
  pthread_mutex_t lock; 
public: 
  Queue() {
    lock = PTHREAD_MUTEX_INITIALIZER;
  }

  ~Queue() {
    // TBD
  }

  void send(Task m) {
    pthread_mutex_lock(&lock); 
    tasks.push(m);
    pthread_mutex_unlock(&lock);
    return; 
  }

  Task receive() {
    pthread_mutex_lock(&lock);
    Task t = (Task) tasks.front();
    tasks.pop();
    pthread_mutex_unlock(&lock); 
    return t;
  }
}; 

typedef struct __comms {
  Queue<Task> * in; 
  Queue<Task> * out; 
} COMMS; 

Task f(Task x) {
  return x;
}

void * body(void * x) {
  COMMS * q = (COMMS *) x; 
  int * i = new int();

  while(true) {
    Task t = (q->in)->receive();
    if(t.length() < 0) 
      break; // EOS
    Task r = f(t); 
    (*i)++;
    q->out->send(r);
  }
  return ((void *) i);
}

int main(int argc, char * argv []) {

  Queue<Task> tasks;
  Queue<Task> ress; 
  COMMS c; 
  c.in = &tasks;
  c.out = &ress;
  
  int nw = atoi(argv[1]);
  pthread_t * tid = new pthread_t[nw];

  for(int i=0; i<nw; i++) {
    int ret = pthread_create(&tid[i], NULL, body, (void *) &c);
    if(ret != 0) {
      // TBD
      cerr << "error creating thread " << i << endl; 
    }
  }
  return(0);
}