Add `Hash::from_slice` to handle conversion from `&[u8]` bytes

This is a convenience method, to avoid having to first call
`<[u8; 32]>::try_from(slice)?`.

2 files changed, 17 insertions, 0 deletions

diff --git a/src/lib.rs b/src/lib.rs
index 37c2c0b..355668f 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -236,6 +236,13 @@ impl Hash {
         Self(bytes)
     }
 
+    /// Create a `Hash` from its raw bytes representation as a slice.
+    ///
+    /// Returns an error if the slice is not exactly 32 bytes long.
+    pub fn from_slice(bytes: &[u8]) -> Result<Self, core::array::TryFromSliceError> {
+        Ok(Self::from_bytes(bytes.try_into()?))
+    }
+
     /// Encode a `Hash` in lowercase hexadecimal.
     ///
     /// The returned [`ArrayString`] is a fixed size and doesn't allocate memory
diff --git a/src/test.rs b/src/test.rs
index 3041b0c..506d7aa 100644
--- a/src/test.rs
+++ b/src/test.rs
@@ -763,6 +763,16 @@ fn test_hash_conversions() {
     let hex = hash1.to_hex();
     let hash3 = crate::Hash::from_hex(hex.as_bytes()).unwrap();
     assert_eq!(hash1, hash3);
+
+    let slice1: &[u8] = bytes1.as_slice();
+    let hash4 = crate::Hash::from_slice(slice1).expect("correct length");
+    assert_eq!(hash1, hash4);
+
+    assert!(crate::Hash::from_slice(&[]).is_err());
+    assert!(crate::Hash::from_slice(&[42]).is_err());
+    assert!(crate::Hash::from_slice([42; 31].as_slice()).is_err());
+    assert!(crate::Hash::from_slice([42; 33].as_slice()).is_err());
+    assert!(crate::Hash::from_slice([42; 100].as_slice()).is_err());
 }
 
 #[test]