1 files changed, 69 insertions, 0 deletions
diff --git a/vendor/der/src/referenced.rs b/vendor/der/src/referenced.rs
new file mode 100644
index 0000000..b0c8f03
--- /dev/null
+++ b/vendor/der/src/referenced.rs
@@ -0,0 +1,69 @@
+//! A module for working with referenced data.
+
+/// A trait for borrowing data from an owned struct
+pub trait OwnedToRef {
+    /// The resulting type referencing back to Self
+    type Borrowed<'a>
+    where
+        Self: 'a;
+
+    /// Creates a new object referencing back to the self for storage
+    fn owned_to_ref(&self) -> Self::Borrowed<'_>;
+}
+
+/// A trait for cloning a referenced structure and getting owned objects
+///
+/// This is the pendant to [`OwnedToRef`]
+pub trait RefToOwned<'a> {
+    /// The resulting type after obtaining ownership.
+    type Owned: OwnedToRef<Borrowed<'a> = Self>
+    where
+        Self: 'a;
+
+    /// Creates a new object taking ownership of the data
+    fn ref_to_owned(&self) -> Self::Owned;
+}
+
+impl<T> OwnedToRef for Option<T>
+where
+    T: OwnedToRef,
+{
+    type Borrowed<'a> = Option<T::Borrowed<'a>> where T: 'a;
+
+    fn owned_to_ref(&self) -> Self::Borrowed<'_> {
+        self.as_ref().map(|o| o.owned_to_ref())
+    }
+}
+
+impl<'a, T> RefToOwned<'a> for Option<T>
+where
+    T: RefToOwned<'a> + 'a,
+    T::Owned: OwnedToRef,
+{
+    type Owned = Option<T::Owned>;
+    fn ref_to_owned(&self) -> Self::Owned {
+        self.as_ref().map(|o| o.ref_to_owned())
+    }
+}
+
+#[cfg(feature = "alloc")]
+mod allocating {
+    use super::{OwnedToRef, RefToOwned};
+    use alloc::boxed::Box;
+
+    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()
+        }
+    }
+}