1 files changed, 29 insertions, 0 deletions
diff --git a/pkg/util/ref.go b/pkg/util/ref.go
new file mode 100644
index 0000000..69f7db4
--- /dev/null
+++ b/pkg/util/ref.go
@@ -0,0 +1,29 @@
+package util
+
+import (
+	"lukeshu.com/btrfs-tools/pkg/binstruct"
+)
+
+type File[A ~int64] interface {
+	Name() string
+	Size() (A, error)
+	ReadAt(p []byte, off A) (n int, err error)
+}
+
+type Ref[A ~int64, T any] struct {
+	File File[A]
+	Addr A
+	Data T
+}
+
+func (r *Ref[A, T]) Read() error {
+	size := binstruct.StaticSize(r.Data)
+	buf := make([]byte, size)
+	if _, err := r.File.ReadAt(buf, r.Addr); err != nil {
+		return err
+	}
+	if _, err := binstruct.Unmarshal(buf, &r.Data); err != nil {
+		return err
+	}
+	return nil
+}