Add generic atomic value

sync/atomic/generic.go

@@ -0,0 +1,38 @@
+package uatomic
+
+import "sync/atomic"
+
+// Atom is a generic wrapper for atomic.Value.
+type Atom[T comparable] struct {
+	value atomic.Value
+}
+
+type atomWrapper[T comparable] struct { value T }
+
+// CompareAndSwap executes the compare-and-swap operation for the Atom.
+func (atom *Atom[T]) CompareAndSwap(old, neww T) (swapped bool) {
+	return atom.value.CompareAndSwap(
+		atomWrapper[T] { value: old },
+		atomWrapper[T] { value: neww })
+}
+
+func (atom *Atom[T]) Load() T {
+	return castSafe[T](atom.value.Load)
+}
+
+func (atom *Atom[T]) Store(val T) {
+	atom.value.Store(val)
+}
+
+func (atom *Atom[T]) Swap(neww T) T {
+	return castSafe[T](atom.value.Swap(neww))
+}
+
+func castSafe[T comparable](value any) T {
+	var zero T
+	if value == nil {
+		return zero
+	} else {
+		return value.(T)
+	}
+}