add count to list, fix cm wrong capacity (#22)

internal/list.go

@@ -18,7 +18,8 @@ const (
 // The zero value for List is an empty list ready to use.
 type List[K comparable, V any] struct {
 	root     Entry[K, V] // sentinel list element, only &root, root.prev, and root.next are used
-	len      int         // current list length excluding (this) sentinel element
+	len      int         // current list length(sum of costs) excluding (this) sentinel element
+	count    int         // count of entries in list
 	capacity uint
 	bounded  bool
 	listType uint8 // 1 tinylfu list, 2 timerwheel list
@@ -97,6 +98,7 @@ func (l *List[K, V]) insert(e, at *Entry[K, V]) *Entry[K, V] {
 	e.next(l.listType).setPrev(e, l.listType)
 	if l.bounded {
 		l.len += int(e.cost.Load())
+		l.count += 1
 	}
 	return evicted
 }
@@ -122,6 +124,7 @@ func (l *List[K, V]) remove(e *Entry[K, V]) {
 	}
 	if l.bounded {
 		l.len -= int(e.cost.Load())
+		l.count -= 1
 	}
 }
 

internal/list_test.go

@@ -55,6 +55,24 @@ func TestList(t *testing.T) {
 
 }
 
+func TestListCountCost(t *testing.T) {
+	l := NewList[string, string](100, LIST_PROBATION)
+	require.Equal(t, uint(100), l.capacity)
+	require.Equal(t, LIST_PROBATION, l.listType)
+	for i := 0; i < 5; i++ {
+		evicted := l.PushFront(NewEntry(fmt.Sprintf("%d", i), "", 20, 0))
+		require.Nil(t, evicted)
+	}
+	require.Equal(t, 100, l.len)
+	require.Equal(t, 5, l.count)
+	for i := 0; i < 3; i++ {
+		entry := l.PopTail()
+		require.NotNil(t, entry)
+	}
+	require.Equal(t, 40, l.len)
+	require.Equal(t, 2, l.count)
+}
+
 func TestWheelList(t *testing.T) {
 	l := NewList[string, string](5, WHEEL_LIST)
 	require.Equal(t, uint(5), l.capacity)

internal/tlfu.go

@@ -96,7 +96,7 @@ func (t *TinyLfu[K, V]) Set(entry *Entry[K, V]) *Entry[K, V] {
 				return entry
 			}
 		} else {
-			count := t.slru.probation.len + t.slru.protected.len
+			count := t.slru.probation.count + t.slru.protected.count
 			t.sketch.ensureCapacity(uint(count + count/100))
 		}
 		evicted := t.slru.insert(entry)