/* ************************************************************************
*  File: events.h                                                         *
*                                                                         *
*  Usage: structures and prototypes for events                            *
*                                                                         *
*  Written by Eric Green (ejg3@cornell.edu)                               *
*                                                                         *
*  Changes:                                                               *
*      3/6/98 ejg:  Changed return type of EVENTFUNC from void to long.   *
*                   Moved struct event definition to events.c.            *
************************************************************************ */

/*
** how often will heartbeat() call the 'wait' event function?
*/
#define PULSE_DG_EVENT 1


/********** Event related section *********/

#define EVENTFUNC(name) long (name)(void *event_obj)


/*
** define event related structures
*/
struct event {
  EVENTFUNC(*func);
  void *event_obj;
  struct q_element *q_el;
};

/****** End of Event related info ********/

/***** Queue related info ******/

/* number of queues to use (reduces enqueue cost) */
#define NUM_EVENT_QUEUES    10

struct queue {
  struct q_element *head[NUM_EVENT_QUEUES], *tail[NUM_EVENT_QUEUES];
};

struct q_element {
  void *data;
  long key;
  struct q_element *prev, *next;
};
/****** End of Queue related info ********/

/* - events - function protos need by other modules */
void event_init(void);
struct event *event_create(EVENTFUNC(*func), void *event_obj, long when);
void event_cancel(struct event *event);
void event_process(void);
long event_time(struct event *event);
void event_free_all(void);

/* - queues - function protos need by other modules */
struct queue *queue_init(void);
struct q_element *queue_enq(struct queue *q, void *data, long key);
void queue_deq(struct queue *q, struct q_element *qe);
void *queue_head(struct queue *q);
long queue_key(struct queue *q);
long queue_elmt_key(struct q_element *qe);
void queue_free(struct queue *q);
int  event_is_queued(struct event *event);