Update main.c

README.md

@@ -7,14 +7,14 @@ Testing some (potentially stupid 😅) ideas for a generic event system implment
 
 - [x] ~~Implement system initialisation~~
 - [x] ~~Implement system deinitialisation~~
-- [ ] Implement registering new events
+- [x] ~~Implement registering new events~~
     - [x] ~~Re-use a free slot if one exists~~
     - [x] ~~Register a event new when not out of capacity and no free events exist~~
-    - [ ] Re-allocate to add more events when out of capacity
+    - [x] ~~Re-allocate to add more events when out of capacity~~
 - [x] ~~Implement removing a previously registered event~~
-- [ ] Implement adding new event listeners
+- [x] ~~Implement adding new event listeners~~
     - [x] ~~Re-use a free slot if one exists~~
     - [x] ~~Register a new listeners when not out of capacity and no free listeners exist~~
-    - [ ] Re-allocate to add more listeners when out of capacity
+    - [x] ~~Re-allocate to add more listeners when out of capacity~~
 - [x] ~~Implement removing an existing listener~~
 - [x] ~~Implement emitting an event~~

src/event_system.c

@@ -3,6 +3,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <stdbool.h>
+#include <time.h>
 #include <sys/mman.h>
 
 #define MAGIC 0x4556535953
@@ -17,9 +18,13 @@
 #define IS_INVALID_EVENT(EV) (EV.id == 0)
 #define IS_INVALID_LISTENER(LS) (LS.id == 0 || IS_INVALID_EVENT(LS.event))
 
+#define CB_ARR_SIZE(CAPACITY) ((CAPACITY + 1) * sizeof(EventCallback))
+#define FREE_CB_ARR_SIZE(CAPACITY) (CAPACITY * sizeof(u64))
+
 typedef struct es_internal ESInternal;
 struct es_internal {
   u64  magic;
+  u64  id;
   u64  alloc_size;
   u64  event_capacity;
   u64  event_count;
@@ -49,10 +54,20 @@ internal void          *alloc(u64 size);
 internal ESInternal    *get_event_system_internal(EventSystem event_system);
 internal EventSlot     *get_event_slots_array(const ESInternal *es);
 internal u64           *get_free_array(const ESInternal *es);
+internal void          reallocate_system(EventSystem *event_system, ESInternal *es);
+internal void          copy_event_data(const ESInternal *src, ESInternal *dst);
 internal EventInternal *get_event(const ESInternal *es, Event event);
 internal EventInternal *get_event_from_offset(const ESInternal *es, u64 offset);
+internal u64           get_largest_capacity(const ESInternal *es);
+
+internal bool seeded = false;
 
 EventSystem es_init(u64 initial_event_capacity, u64 initial_listeners_capacity) {
+  if (!seeded) {
+    srand(time(0));
+    seeded = true;
+  }
+
   // Double event capacity to reduce chances of reallocation
   u64 event_capacity     = initial_event_capacity * 2;
   // Double listener capacity to reduce chances of reallocation
@@ -62,9 +77,9 @@ EventSystem es_init(u64 initial_event_capacity, u64 initial_listeners_capacity)
   u64 event_offsets      = (event_capacity + 1) * sizeof(EventSlot);
   u64 free_slots         = event_capacity * sizeof(u64);
   u64 events             = event_capacity * sizeof(EventInternal);
-  // Increase listener capacity by one to account for 0th EventListener being invalid
-  u64 event_callbacks    = (callback_capacity + 1) * sizeof(EventCallback *);
-  u64 event_free         = callback_capacity * sizeof(u64 *);
+  // Increases listener capacity by one to account for 0th EventListener being invalid
+  u64 event_callbacks    = CB_ARR_SIZE(callback_capacity);
+  u64 event_free         = FREE_CB_ARR_SIZE(callback_capacity);
   u64 callbacks          = event_capacity * event_callbacks;
   u64 free_callbacks     = event_capacity * event_free;
   u64 alloc_size         = system + event_offsets + free_slots + events + callbacks + free_callbacks;
@@ -87,6 +102,7 @@ EventSystem es_init(u64 initial_event_capacity, u64 initial_listeners_capacity)
   ESInternal *event_system = (ESInternal *)buffer;
 
   event_system->magic                     = MAGIC;
+  event_system->id                        = (u64)time(0) + (u64)rand();
   event_system->alloc_size                = alloc_size;
   event_system->event_capacity            = event_capacity;
   event_system->event_count               = 0;
@@ -143,8 +159,6 @@ Event es_register_event(EventSystem *event_system) {
     goto RETURN_EVENT;
   }
 
-  event.system = *event_system;
-
   EventSlot *event_slots_array = get_event_slots_array(es);
 
   if (es->free_count > 0) {
@@ -159,11 +173,12 @@ Event es_register_event(EventSystem *event_system) {
   }
 
   if (es->event_count >= es->event_capacity) {
-    // TODO (Abdelrahman): Handle reallocating when out of events
-    goto RETURN_EVENT;
+    reallocate_system(event_system, es);
   }
 
   event.id     = ++(es->event_count);
+  event.system = es->id;
+
   event_slots_array[event.id].registered = true;
 
 RETURN_EVENT:
@@ -171,21 +186,25 @@ RETURN_EVENT:
 }
 
 void es_deregister_event(EventSystem event_system, Event *event) {
-  if (IS_INVALID_SYSTEM(event_system) || IS_INVALID_EVENT((*event)) || event_system.id != event->system.id) {
+  if (IS_INVALID_SYSTEM(event_system) || IS_INVALID_EVENT((*event))) {
     return;
   }
 
   ESInternal *es = get_event_system_internal(event_system);
-  if (!VALID_MAGIC(es) || event->id > es->event_count) {
+  if (!VALID_MAGIC(es) || event->system != es->id || event->id > es->event_count) {
     return;
   }
 
   EventSlot *event_slots_array = get_event_slots_array(es);
   u64 *free_array              = get_free_array(es);
+  EventInternal *ev            = get_event(es, *event);
 
   event_slots_array[event->id].registered = false;
   free_array[(es->free_count)++]          = event->id;
 
+  ev->count      = 0;
+  ev->free_count = 0;
+
   if (event->id == es->event_count) {
     es->event_count -= 1;
   }
@@ -196,12 +215,12 @@ void es_deregister_event(EventSystem event_system, Event *event) {
 EventListener es_add_event_listener(EventSystem *event_system, Event event, EventCallback callback) {
   EventListener listener = INVALID_LISTENER;
 
-  if (!event_system || IS_INVALID_SYSTEM((*event_system)) || IS_INVALID_EVENT(event) || event_system->id != event.system.id || !callback) {
+  if (!event_system || IS_INVALID_SYSTEM((*event_system)) || IS_INVALID_EVENT(event) || !callback) {
     goto RETURN_LISTENER;
   }
 
   ESInternal *es = get_event_system_internal(*event_system);
-  if (!VALID_MAGIC(es)) {
+  if (!VALID_MAGIC(es) || event.system != es->id) {
     goto RETURN_LISTENER;
   }
 
@@ -220,8 +239,8 @@ EventListener es_add_event_listener(EventSystem *event_system, Event event, Even
   }
 
   if (ev->count >= ev->capacity) {
-    // TODO (Abdelrahman): Handle reallocating when out of callbacks
-    goto RETURN_LISTENER;
+    reallocate_system(event_system, es);
+    ev = get_event(es, event);
   }
 
   u64 id = ++(ev->count);
@@ -236,7 +255,7 @@ RETURN_LISTENER:
 }
 
 void es_remove_event_listener(EventSystem event_system, EventListener listener) {
-  if (IS_INVALID_SYSTEM(event_system) || IS_INVALID_LISTENER(listener) || event_system.id != listener.event.system.id) {
+  if (IS_INVALID_SYSTEM(event_system) || IS_INVALID_LISTENER(listener)) {
     return;
   }
 
@@ -264,12 +283,12 @@ void es_remove_event_listener(EventSystem event_system, EventListener listener)
 }
 
 void es_emit_event(EventSystem event_system, Event event, void *data) {
-  if (IS_INVALID_SYSTEM(event_system) || IS_INVALID_EVENT(event) || event_system.id != event.system.id) {
+  if (IS_INVALID_SYSTEM(event_system) || IS_INVALID_EVENT(event)) {
     return;
   }
 
   ESInternal *es = get_event_system_internal(event_system);
-  if (!VALID_MAGIC(es) || event.id > es->event_count) {
+  if (!VALID_MAGIC(es) || event.system != es->id || event.id > es->event_count) {
     return;
   }
 
@@ -302,6 +321,41 @@ internal u64 *get_free_array(const ESInternal *es) {
   return (u64 *)((uptr)es + es->free_offset);
 }
 
+internal void reallocate_system(EventSystem *event_system, ESInternal *es) {
+  u64 new_callback_capacity    = get_largest_capacity(es);
+  EventSystem event_system_new = es_init(es->event_capacity, new_callback_capacity);
+  ESInternal  *es_new          = get_event_system_internal(event_system_new);
+
+  es_new->id          = es->id;
+  es_new->event_count = es->event_count;
+
+  copy_event_data(es, es_new);
+
+  es_deinit(event_system);
+  event_system->id = event_system_new.id;
+  es = es_new;
+}
+
+internal void copy_event_data(const ESInternal *src, ESInternal *dst) {
+  EventSlot *slots_src = get_event_slots_array(src);
+  EventSlot *slots_dst = get_event_slots_array(dst);
+
+  EventInternal *ev_src;
+  EventInternal *ev_dst;
+  for (u64 i = 1; i <= src->event_count; ++i) {
+    slots_dst[i].registered = slots_src[i].registered;
+
+    ev_src = get_event_from_offset(src, slots_src[i].offset);
+    ev_dst = get_event_from_offset(dst, slots_dst[i].offset);
+
+    ev_dst->count      = ev_src->count;
+    ev_dst->free_count = ev_src->free_count;
+
+    memcpy((void *)(ev_dst->free),      (const void *)(ev_src->free),      FREE_CB_ARR_SIZE(ev_src->capacity));
+    memcpy((void *)(ev_dst->callbacks), (const void *)(ev_src->callbacks), CB_ARR_SIZE(ev_src->capacity));
+  }
+}
+
 internal EventInternal *get_event(const ESInternal *es, Event event) {
   EventSlot *event_slots_array = get_event_slots_array(es);
   return get_event_from_offset(es, event_slots_array[event.id].offset);
@@ -310,3 +364,18 @@ internal EventInternal *get_event(const ESInternal *es, Event event) {
 internal EventInternal *get_event_from_offset(const ESInternal *es, u64 offset) {
   return (EventInternal *)((uptr)es + offset);
 }
+
+internal u64 get_largest_capacity(const ESInternal *es) {
+  EventSlot *event_slots_array   = get_event_slots_array(es);
+  u64 capacity                   = es->initial_callback_capacity;
+
+  EventInternal *event;
+  for (u64 i = 1; i <= es->event_count; ++i) {
+    event = get_event_from_offset(es, event_slots_array[i].offset);
+    if (event->capacity > capacity) {
+      capacity = event->capacity;
+    }
+  }
+
+  return capacity;
+}

src/event_system.h

@@ -2,13 +2,6 @@
 
 #include "aliases.h"
 
-enum {
-  ES_INIT_SUCCESS = 0,
-  ES_INIT_NULL_POINTER,
-  ES_INIT_ALREADY_INITIALISED,
-  ES_INIT_ALLOCATION_FAILED,
-};
-
 typedef struct event_system EventSystem;
 struct event_system {
   u64 id;
@@ -16,8 +9,8 @@ struct event_system {
 
 typedef struct event Event;
 struct event {
-  EventSystem system;
   u64 id;
+  u64 system;
 };
 
 typedef struct event_listener EventListener;

src/main.c

@@ -37,7 +37,7 @@ int main(void) {
   EventListener listeners[COUNT_EVENTS] = {0};
   EventCallback callbacks[COUNT_EVENTS] = {window_event_handler, keyboard_event_handler, mouse_event_handler};
 
-  EventSystem es = es_init(COUNT_EVENTS, 64);
+  EventSystem es = es_init(COUNT_EVENTS, 4);
 
   for (int i = 0; i < COUNT_EVENTS; ++i) {
     events[i]    = es_register_event(&es);
@@ -67,6 +67,22 @@ int main(void) {
   es_remove_event_listener(es, listener);
   es_deregister_event(es, &extra_event);
 
+  for (int i = 0; i < 10; ++i) {
+    es_register_event(&es);
+  }
+
+  printf("AFTER REALLOCATION WHEN OUT OF EVENTS\n\n");
+  es_emit_event(es, events[EVENT_WINDOW],   (void *)&window_event);
+  es_emit_event(es, events[EVENT_KEYBOARD], (void *)&keyboard_event);
+  es_emit_event(es, events[EVENT_MOUSE],    (void *)&mouse_event);
+
+  for (int i = 0; i < 20; ++i) {
+    es_add_event_listener(&es, events[EVENT_WINDOW], callbacks[EVENT_WINDOW]);
+  }
+
+  printf("AFTER REALLOCATION WHEN OUT OF CALLBACKS\n\n");
+  es_emit_event(es, events[EVENT_WINDOW], (void *)&window_event);
+
   for (int i = 0; i < COUNT_EVENTS; ++i) {
     es_remove_event_listener(es, listeners[i]);
     es_deregister_event(es, &events[i]);