From 7c65944a03ec0ea3739cbe0b8117257a4d91137a Mon Sep 17 00:00:00 2001
From: Michael Sproul <michael@sigmaprime.io>
Date: Mon, 13 Mar 2023 10:47:13 +1100
Subject: [PATCH] Implement TreeHash for 48-byte array (#3)

---
 tree_hash/src/impls.rs | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/tree_hash/src/impls.rs b/tree_hash/src/impls.rs
index cf05d2a..899356f 100644
--- a/tree_hash/src/impls.rs
+++ b/tree_hash/src/impls.rs
@@ -82,6 +82,26 @@ macro_rules! impl_for_lt_32byte_u8_array {
 impl_for_lt_32byte_u8_array!(4);
 impl_for_lt_32byte_u8_array!(32);
 
+impl TreeHash for [u8; 48] {
+    fn tree_hash_type() -> TreeHashType {
+        TreeHashType::Vector
+    }
+
+    fn tree_hash_packed_encoding(&self) -> PackedEncoding {
+        unreachable!("Vector should never be packed.")
+    }
+
+    fn tree_hash_packing_factor() -> usize {
+        unreachable!("Vector should never be packed.")
+    }
+
+    fn tree_hash_root(&self) -> Hash256 {
+        let values_per_chunk = BYTES_PER_CHUNK;
+        let minimum_chunk_count = (48 + values_per_chunk - 1) / values_per_chunk;
+        merkle_root(self, minimum_chunk_count)
+    }
+}
+
 impl TreeHash for U128 {
     fn tree_hash_type() -> TreeHashType {
         TreeHashType::Basic