Add sync.Wait_Group

core/sync/wait_group.odin

@@ -0,0 +1,58 @@
+package sync
+
+import "intrinsics"
+
+Wait_Group :: struct {
+	counter: int,
+	mutex:   Blocking_Mutex,
+	cond:    Condition,
+}
+
+wait_group_init :: proc(wg: ^Wait_Group) {
+	wg.counter = 0;
+	blocking_mutex_init(&wg.mutex);
+	condition_init(&wg.cond, &wg.mutex);
+}
+
+
+wait_group_destroy :: proc(wg: ^Wait_Group) {
+	condition_destroy(&wg.cond);
+	blocking_mutex_destroy(&wg.mutex);
+}
+
+wait_group_add :: proc(wg: ^Wait_Group, delta: int) {
+	if delta == 0 {
+		return;
+	}
+
+	blocking_mutex_lock(&wg.mutex);
+	defer blocking_mutex_unlock(&wg.mutex);
+
+	intrinsics.atomic_add(&wg.counter, delta);
+	if wg.counter < 0 {
+		panic("sync.Wait_Group negative counter");
+	}
+	if wg.counter == 0 {
+		condition_broadcast(&wg.cond);
+		if wg.counter != 0 {
+			panic("sync.Wait_Group misuse: sync.wait_group_add called concurrently with sync.wait_group_wait");
+		}
+	}
+}
+
+wait_group_done :: proc(wg: ^Wait_Group) {
+	wait_group_add(wg, -1);
+}
+
+wait_group_wait :: proc(wg: ^Wait_Group) {
+	blocking_mutex_lock(&wg.mutex);
+	defer blocking_mutex_unlock(&wg.mutex);
+
+	if wg.counter != 0 {
+		condition_wait_for(&wg.cond);
+		if wg.counter != 0 {
+			panic("sync.Wait_Group misuse: sync.wait_group_add called concurrently with sync.wait_group_wait");
+		}
+	}
+}
+