Trim 22 bytes from struct event on 32 bit platforms, more on 64-bit platforms.

svn:r1292

ChangeLog

@@ -24,6 +24,8 @@ Changes in 2.0.2-alpha:
  o Move the EVBUFFER_INPUT and EVBUFFER_OUTPUT macros to bufferevent_compat.h
  o Add a bufferevent_getfd() function to mirror bufferevent_setfd()
  o Make bufferevent_setfd() return an error code if the operation is not successful.
+ o Shave 22 bytes off struct event on 32-bit platforms by shrinking and re-ordering fields.  The savings on 64-bit platforms is likely higher.
+ o Cap the maximum number of priorities at 256.
 
 Changes in 2.0.1-alpha:
  o free minheap on event_base_free(); from Christopher Layne

event-internal.h

@@ -50,6 +50,11 @@ extern "C" {
 #define ev_ncalls	_ev.ev_signal.ev_ncalls
 #define ev_pncalls	_ev.ev_signal.ev_pncalls
 
+/* Possible event closures. */
+#define EV_CLOSURE_NONE 0
+#define EV_CLOSURE_SIGNAL 1
+#define EV_CLOSURE_PERSIST 2
+
 /** Structure to define the backend of a given event_base. */
 struct eventop {
 	/** The name of this backend. */

event.c

@@ -551,7 +551,8 @@ event_base_priority_init(struct event_base *base, int npriorities)
 {
 	int i;
 
-	if (base->event_count_active || npriorities < 1)
+	if (base->event_count_active || npriorities < 1
+	    || npriorities >= EVENT_MAX_PRIORITIES)
 		return (-1);
 
 	if (npriorities == base->nactivequeues)
@@ -648,11 +649,20 @@ event_process_active_single_queue(struct event_base *base,
 		EVBASE_RELEASE_LOCK(base,
 		    EVTHREAD_WRITE, th_base_lock);
 
-		if (ev->ev_closure != NULL)
-			(*ev->ev_closure)(base, ev);
-		else
+		switch (ev->ev_closure) {
+		case EV_CLOSURE_SIGNAL:
+			event_signal_closure(base, ev);
+			break;
+		case EV_CLOSURE_PERSIST:
+			event_persist_closure(base, ev);
+			break;
+		default:
+		case EV_CLOSURE_NONE:
 			(*ev->ev_callback)(
 				(int)ev->ev_fd, ev->ev_res, ev->ev_arg);
+			break;
+		}
+
 		if (base->event_break)
 			return -1;
 		EVBASE_ACQUIRE_LOCK(base, EVTHREAD_WRITE, th_base_lock);
@@ -969,13 +979,13 @@ event_set(struct event *ev, evutil_socket_t fd, short events,
 		if ((events & (EV_READ|EV_WRITE)) != 0)
 			event_errx(1, "%s: EV_SIGNAL incompatible use",
 			    __func__);
-		ev->ev_closure = event_signal_closure;
+		ev->ev_closure = EV_CLOSURE_SIGNAL;
 	} else {
 		if (events & EV_PERSIST) {
 			timerclear(&ev->ev_io_timeout);
-			ev->ev_closure = event_persist_closure;
+			ev->ev_closure = EV_CLOSURE_PERSIST;
 		} else {
-			ev->ev_closure = NULL;
+			ev->ev_closure = EV_CLOSURE_NONE;
 		}
 	}
 
@@ -1198,7 +1208,7 @@ event_add_internal(struct event *ev, const struct timeval *tv)
 		 * for persistent timeout events, we remember the
 		 * timeout value and re-add the event.
 		 */
-		if (ev->ev_closure == event_persist_closure)
+		if (ev->ev_closure == EV_CLOSURE_PERSIST)
 			ev->ev_io_timeout = *tv;
 
 		/*

include/event2/event.h

@@ -546,6 +546,7 @@ ev_uint32_t event_get_version_number(void);
  * headers. */
 #define LIBEVENT_VERSION_NUMBER _EVENT_NUMERIC_VERSION
 
+#define EVENT_MAX_PRIORITIES 256
 /**
   Set the number of different event priorities (threadsafe variant).
 

include/event2/event_struct.h

@@ -80,10 +80,10 @@ struct event {
 	TAILQ_ENTRY (event) (ev_active_next);
 	TAILQ_ENTRY (event) (ev_next);
 	int min_heap_idx;	/* for managing timeouts */
+	evutil_socket_t ev_fd;
 
 	struct event_base *ev_base;
 
-	evutil_socket_t ev_fd;
 	union {
 		/* used for io events */
 		struct {
@@ -101,18 +101,15 @@ struct event {
 	} _ev;
 
 	short ev_events;
-
+	short ev_res;		/* result passed to event callback */
+	short ev_flags;
+	ev_uint8_t ev_pri;	/* smaller numbers are higher priority */
+	ev_uint8_t ev_closure;
 	struct timeval ev_timeout;
 
-	int ev_pri;		/* smaller numbers are higher priority */
-
 	/* allows us to adopt for different types of events */
-	void (*ev_closure)(struct event_base *, struct event *);
 	void (*ev_callback)(evutil_socket_t, short, void *arg);
 	void *ev_arg;
-
-	int ev_res;		/* result passed to event callback */
-	int ev_flags;
 };
 
 #ifdef EVENT_FD