From 2b6ef31469edd93d59655afa41f3130f3ab058ba Mon Sep 17 00:00:00 2001
From: "Tobin C. Harding" <me@tobin.cc>
Date: Thu, 20 Feb 2025 13:53:47 +1100
Subject: [PATCH] hashes: Add hash_byte_chunks function to modules

 Add a standalone `hash_byte_chunks` function that is a drop in
 replacement for `GeneralHash::hash_byte_chunks`. Do not add it to
 `hmac` - this is in parity with the current code because `Hmac` does
 not implement `GeneralHash::hash_byte_chunks`.
---
 hashes/src/internal_macros.rs | 17 ++++++++++++++++-
 hashes/src/sha256t/mod.rs     | 16 ++++++++++++++++
 2 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/hashes/src/internal_macros.rs b/hashes/src/internal_macros.rs
index 41ffab593..fee359a9e 100644
--- a/hashes/src/internal_macros.rs
+++ b/hashes/src/internal_macros.rs
@@ -80,6 +80,21 @@ macro_rules! general_hash_type {
             engine.finalize()
         }
 
+        /// Hashes all the byte slices retrieved from the iterator together.
+        pub fn hash_byte_chunks<B, I>(byte_slices: I) -> Hash
+        where
+            B: AsRef<[u8]>,
+            I: IntoIterator<Item = B>,
+        {
+            use crate::HashEngine as _;
+
+            let mut engine = Hash::engine();
+            for slice in byte_slices {
+                engine.input(slice.as_ref());
+            }
+            engine.finalize()
+        }
+
         $crate::internal_macros::hash_type_no_default!($bits, $reverse, $doc);
 
         impl Hash {
@@ -99,7 +114,7 @@ macro_rules! general_hash_type {
                 B: AsRef<[u8]>,
                 I: IntoIterator<Item = B>,
             {
-                <Self as $crate::GeneralHash>::hash_byte_chunks(byte_slices)
+                hash_byte_chunks(byte_slices)
             }
         }
     };
diff --git a/hashes/src/sha256t/mod.rs b/hashes/src/sha256t/mod.rs
index be144f2f2..d5acd5edf 100644
--- a/hashes/src/sha256t/mod.rs
+++ b/hashes/src/sha256t/mod.rs
@@ -21,6 +21,22 @@ where
     engine.finalize()
 }
 
+/// Hashes all the byte slices retrieved from the iterator together.
+pub fn hash_byte_chunks<B, I, T>(byte_slices: I) -> Hash<T>
+where
+    B: AsRef<[u8]>,
+    I: IntoIterator<Item = B>,
+    T: Tag,
+{
+    use crate::HashEngine as _;
+
+    let mut engine = HashEngine::default();
+    for slice in byte_slices {
+        engine.input(slice.as_ref());
+    }
+    engine.finalize()
+}
+
 /// Trait representing a tag that can be used as a context for SHA256t hashes.
 pub trait Tag {
     /// The [`Midstate`] after pre-tagging the hash engine.