tls_codec: implement traits for Box<T> (#1586)

* implement traits for Box<T>
* restrict impls to "std"
* allow use of alloc::boxed::Box

tls_codec/src/primitives.rs

@@ -1,6 +1,6 @@
 //! Codec implementations for unsigned integer primitives.
 
-use alloc::vec::Vec;
+use alloc::{boxed::Box, vec::Vec};
 
 use crate::{DeserializeBytes, SerializeBytes, U24};
 
@@ -371,3 +371,40 @@ impl<T> SerializeBytes for PhantomData<T> {
         Ok(vec![])
     }
 }
+
+impl<T: Size> Size for Box<T> {
+    #[inline(always)]
+    fn tls_serialized_len(&self) -> usize {
+        self.as_ref().tls_serialized_len()
+    }
+}
+
+impl<T: Serialize> Serialize for Box<T> {
+    #[cfg(feature = "std")]
+    #[inline(always)]
+    fn tls_serialize<W: Write>(&self, writer: &mut W) -> Result<usize, Error> {
+        self.as_ref().tls_serialize(writer)
+    }
+}
+
+impl<T: SerializeBytes> SerializeBytes for Box<T> {
+    #[inline(always)]
+    fn tls_serialize(&self) -> Result<Vec<u8>, Error> {
+        self.as_ref().tls_serialize()
+    }
+}
+
+impl<T: Deserialize> Deserialize for Box<T> {
+    #[cfg(feature = "std")]
+    #[inline(always)]
+    fn tls_deserialize<R: Read>(bytes: &mut R) -> Result<Self, Error> {
+        T::tls_deserialize(bytes).map(Box::new)
+    }
+}
+
+impl<T: DeserializeBytes> DeserializeBytes for Box<T> {
+    #[inline(always)]
+    fn tls_deserialize_bytes(bytes: &[u8]) -> Result<(Self, &[u8]), Error> {
+        T::tls_deserialize_bytes(bytes).map(|(v, r)| (Box::new(v), r))
+    }
+}