feat: optimized hash_elements for blake3 hasher

src/hash/blake/tests.rs

@@ -1,6 +1,22 @@
 use super::*;
 use crate::utils::collections::Vec;
 use proptest::prelude::*;
+use rand_utils::rand_vector;
+
+#[test]
+fn blake3_hash_elements() {
+    // test multiple of 8
+    let elements = rand_vector::<Felt>(16);
+    let expected = compute_expected_element_hash(&elements);
+    let actual: [u8; 32] = hash_elements(&elements);
+    assert_eq!(&expected, &actual);
+
+    // test not multiple of 8
+    let elements = rand_vector::<Felt>(17);
+    let expected = compute_expected_element_hash(&elements);
+    let actual: [u8; 32] = hash_elements(&elements);
+    assert_eq!(&expected, &actual);
+}
 
 proptest! {
     #[test]
@@ -18,3 +34,14 @@ proptest! {
         Blake3_256::hash(vec);
     }
 }
+
+// HELPER FUNCTIONS
+// ================================================================================================
+
+fn compute_expected_element_hash(elements: &[Felt]) -> blake3::Hash {
+    let mut bytes = Vec::new();
+    for element in elements.iter() {
+        bytes.extend_from_slice(&element.as_int().to_le_bytes());
+    }
+    blake3::hash(&bytes)
+}