#ifndef __PT_H__
#define __PT_H__

#include "lc.h"

struct pt {
  lc_t lc;
};

#define PT_WAITING 0
#define PT_YIELDED 1
#define PT_EXITED  2
#define PT_ENDED   3

#define PT_INIT(pt)   LC_INIT((pt)->lc)
#define PT_THREAD(name_args) char name_args
#define PT_BEGIN(pt) { char PT_YIELD_FLAG = 1; LC_RESUME((pt)->lc)
#define PT_END(pt) LC_END((pt)->lc); PT_YIELD_FLAG = 0; \
                   PT_INIT(pt); return PT_ENDED; }

#define PT_WAIT_UNTIL(pt, condition)	        \
  do {						\
    LC_SET((pt)->lc);				\
    if(!(condition)) {				\
      return PT_WAITING;			\
    }						\
  } while(0)

#define PT_WAIT_WHILE(pt, cond)  PT_WAIT_UNTIL((pt), !(cond))

#define PT_WAIT_THREAD(pt, thread) PT_WAIT_WHILE((pt), PT_SCHEDULE(thread))

#define PT_SPAWN(pt, child, thread)		\
  do {						\
    PT_INIT((child));				\
    PT_WAIT_THREAD((pt), (thread));		\
  } while(0)

#define PT_RESTART(pt)				\
  do {						\
    PT_INIT(pt);				\
    return PT_WAITING;			\
  } while(0)

#define PT_EXIT(pt)				\
  do {						\
    PT_INIT(pt);				\
    return PT_EXITED;			\
  } while(0)

#define PT_SCHEDULE(f) ((f) < PT_EXITED)

#define PT_YIELD(pt)				\
  do {						\
     PT_YIELD_FLAG = 0;				\
     LC_SET((pt)->lc);				\
     if(PT_YIELD_FLAG == 0) {			\
        return PT_YIELDED;			\
     }						\
  } while(0)


#define PT_YIELD_UNTIL(pt, cond)		\
  do {						\
    PT_YIELD_FLAG = 0;				\
    LC_SET((pt)->lc);				\
    if((PT_YIELD_FLAG == 0) || !(cond)) {	\
      return PT_YIELDED;			\
    }						\
  } while(0)


#endif /* __PT_H__ */