der: impl RefToOwned/OwnedToRef for &[u8]/Box<[u8]>

Signed-off-by: Arthur Gautier <baloo@superbaloo.net>

der/src/referenced.rs

@@ -1,5 +1,7 @@
 //! A module for working with referenced data.
 
+use alloc::boxed::Box;
+
 /// A trait for borrowing data from an owned struct
 pub trait OwnedToRef {
     /// The resulting type referencing back to Self
@@ -45,3 +47,19 @@ where
         self.as_ref().map(|o| o.ref_to_owned())
     }
 }
+
+impl<'a> RefToOwned<'a> for &'a [u8] {
+    type Owned = Box<[u8]>;
+
+    fn ref_to_owned(&self) -> Self::Owned {
+        Box::from(*self)
+    }
+}
+
+impl OwnedToRef for Box<[u8]> {
+    type Borrowed<'a> = &'a [u8];
+
+    fn owned_to_ref(&self) -> Self::Borrowed<'_> {
+        self.as_ref()
+    }
+}