aead: adds a dev::BicephalBuffer to smoke tests misuse of get_in

Author: baloo

aead/src/dev.rs

@@ -1,16 +1,19 @@
 //! Development-related functionality
 pub use blobby;
 
+#[cfg(feature = "alloc")]
+use {core::fmt, inout::InOutBuf};
+
 /// Define AEAD test
 #[macro_export]
 macro_rules! new_test {
     ($name:ident, $test_name:expr, $cipher:ty $(,)?) => {
         #[test]
         fn $name() {
             use aead::{
-                Aead, KeyInit, Payload,
-                array::{Array, typenum::Unsigned},
+                array::{typenum::Unsigned, Array},
                 dev::blobby::Blob6Iterator,
+                Aead, KeyInit, Payload,
             };
 
             fn run_test(
@@ -75,3 +78,60 @@ macro_rules! new_test {
         }
     };
 }
+
+/// [`BicephalBuffer`] is meant for testing InOut-backed APIs.
+///
+/// It will split the initial buffer in two backing buffers copying the initial data.
+#[cfg(feature = "alloc")]
+pub struct BicephalBuffer {
+    in_buf: alloc::vec::Vec<u8>,
+    out_buf: alloc::vec::Vec<u8>,
+}
+
+#[cfg(feature = "alloc")]
+impl AsRef<[u8]> for BicephalBuffer {
+    fn as_ref(&self) -> &[u8] {
+        &self.out_buf
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl From<&[u8]> for BicephalBuffer {
+    fn from(buf: &[u8]) -> Self {
+        Self {
+            in_buf: buf.to_vec(),
+            out_buf: buf.to_vec(),
+        }
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl From<alloc::vec::Vec<u8>> for BicephalBuffer {
+    fn from(buf: alloc::vec::Vec<u8>) -> Self {
+        Self {
+            in_buf: buf.clone(),
+            out_buf: buf,
+        }
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl BicephalBuffer {
+    /// Get an [`InOutBuf`] from a [`BicephalBuffer`]
+    pub fn to_in_out_buf(&mut self) -> InOutBuf<'_, '_, u8> {
+        InOutBuf::new(self.in_buf.as_slice(), self.out_buf.as_mut_slice())
+            .expect("Invariant violation")
+    }
+
+    /// Return the length of the payload
+    pub fn len(&self) -> usize {
+        self.in_buf.len()
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl fmt::Debug for BicephalBuffer {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "BicephalBuffer {{...}}")
+    }
+}