#include <fstream>
#include <threads>

struct Fibonacci {
      coroutine c;
      coVtable v;
      int fn; // used for communication
};

coroutine* this_coroutine(Fibonacci* this);
void co_main(Fibonacci* this);
coVtable* vtable(Fibonacci* this);

void co_main_fib(void* this) {
      co_main( (Fibonacci*) this );
}

coroutine* this_coroutine_fib(void* this) {
      return this_coroutine( (Fibonacci*) this);
}

void ?{}(Fibonacci* this) {
      this->fn = 0;
      this->v.main = co_main_fib;
      this->v.this_coroutine = this_coroutine_fib;
      start(this);
}

void co_main(Fibonacci* this) {
#ifdef MORE_DEBUG
      sout | "Starting main of coroutine " | this | endl;
      sout | "Started from " | this_coroutine(this)->last | endl;
#endif
      int fn1, fn2; 		// retained between resumes
      this->fn = 0;
      fn1 = this->fn;
      suspend(); 		// return to last resume

      this->fn = 1;
      fn2 = fn1;
      fn1 = this->fn;
      suspend(); 		// return to last resume

      for ( ;; ) {
            this->fn = fn1 + fn2;
            fn2 = fn1;
            fn1 = this->fn;
            suspend(); 	// return to last resume
      }
}

int next(Fibonacci* this) {
      resume(this); // transfer to last suspend
      return this->fn;
}

coroutine* this_coroutine(Fibonacci* this) {
      return &this->c;
}

coVtable* vtable(Fibonacci* this) {
      return &this->v;
}

int main() {
      Fibonacci f1, f2;
#ifdef MORE_DEBUG      
      sout | "User coroutines : " | &f1 | ' ' | &f1 | endl;
#endif
      for ( int i = 1; i <= 10; i += 1 ) {
            sout | next(&f1) | ' ' | next(&f2) | endl;
      }

      return 0;
}