Merge pull request #38 from semihbkgr/fix-fillrate

Fixing fillrate value

e2e_test.go

@@ -130,6 +130,19 @@ func TestGrow2(t *testing.T) {
 	}
 }
 
+func TestFillrate(t *testing.T) {
+	m := New[int, any]()
+	for i := 0; i < 1000; i++ {
+		m.Set(i, nil)
+	}
+	for i := 0; i < 1000; i++ {
+		m.Del(i)
+	}
+	if fr := m.Fillrate(); fr != 0 {
+		t.Errorf("Fillrate should be zero when the map is empty, fillrate: %v", fr)
+	}
+}
+
 func TestDelete(t *testing.T) {
 	m := New[int, *Animal]()
 	cat := &Animal{"cat"}

map.go

@@ -420,14 +420,14 @@ func (m *Map[K, V]) removeItemFromIndex(item *element[K, V]) {
 		ptr := (*unsafe.Pointer)(unsafe.Pointer(uintptr(data.data) + index*intSizeBytes))
 
 		next := item.next()
-		if next != nil && item.keyHash>>data.keyshifts != index {
+		if next != nil && next.keyHash>>data.keyshifts != index {
 			next = nil // do not set index to next item if it's not the same slice index
 		}
-		atomic.CompareAndSwapPointer(ptr, unsafe.Pointer(item), unsafe.Pointer(next))
+		swappedToNil := atomic.CompareAndSwapPointer(ptr, unsafe.Pointer(item), unsafe.Pointer(next)) && next == nil
 
 		if data == m.metadata.Load() { // check that no resize happened
 			m.numItems.Add(^uintptr(0)) // decrement counter
-			if next == nil {
+			if swappedToNil {           // decrement the metadata count if the index is set to nil
 				data.count.Add(^uintptr(0))
 			}
 			return