md5: Implement SerializableState for Md5Core

md5/src/lib.rs

@@ -40,14 +40,19 @@ pub use digest::{self, Digest};
 
 use compress::compress;
 
-use core::{fmt, slice::from_ref};
+use core::{convert::TryInto, fmt, slice::from_ref};
 use digest::{
     block_buffer::Eager,
     core_api::{
         AlgorithmName, Block, BlockSizeUser, Buffer, BufferKindUser, CoreWrapper, FixedOutputCore,
         OutputSizeUser, Reset, UpdateCore,
     },
-    typenum::{Unsigned, U16, U64},
+    crypto_common::{DeserializeStateError, SerializableState, SerializedState},
+    generic_array::{
+        sequence::{Concat, Split},
+        GenericArray,
+    },
+    typenum::{Unsigned, U16, U24, U64, U8},
     HashMarker, Output,
 };
 /// Core MD5 hasher state.
@@ -124,6 +129,38 @@ impl fmt::Debug for Md5Core {
     }
 }
 
+impl SerializableState for Md5Core {
+    type SerializedStateSize = U24;
+
+    fn serialize(&self) -> SerializedState<Self> {
+        let mut serialized_state = GenericArray::<u8, U16>::default();
+
+        for (i, bytes) in serialized_state.as_mut_slice().chunks_mut(4).enumerate() {
+            bytes.copy_from_slice(self.state[i].to_be_bytes().as_slice());
+        }
+
+        let serialized_block_len =
+            GenericArray::<u8, U8>::clone_from_slice(self.block_len.to_be_bytes().as_slice());
+
+        serialized_state.concat(serialized_block_len)
+    }
+
+    fn deserialize(
+        serialized_state: &SerializedState<Self>,
+    ) -> Result<Self, DeserializeStateError> {
+        let (serialized_state, serialized_block_len) = Split::<u8, U16>::split(serialized_state);
+
+        let mut state = [0; 4];
+        for (i, bytes) in serialized_state.chunks(4).enumerate() {
+            state[i] = u32::from_be_bytes(bytes.try_into().unwrap());
+        }
+
+        let block_len = u64::from_be_bytes(serialized_block_len.as_slice().try_into().unwrap());
+
+        Ok(Self { state, block_len })
+    }
+}
+
 /// MD5 hasher state.
 pub type Md5 = CoreWrapper<Md5Core>;
 

md5/tests/mod.rs

@@ -13,3 +13,6 @@ fn md5_rand() {
         hex!("61aec26f1b909578ef638ae02dac0977")[..]
     );
 }
+
+digest::hash_serialization_test!(md5_serialization, Md5,
+    hex!("e5ca2295db93d6dd07ab990fcad2219e00000000000000010113000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"));