Avoid allocation when decoding hex strings

Not particularly useful in user space, but we avoid allocation as much as possible in kernel space and we also want to share the code between the two implementations. Signed-off-by: Ariel Miculas <[email protected]>
project-machine · Jun 29, 2024 · 591ffec · 591ffec
1 parent 7c766f7
commit 591ffec
Showing 1 changed file with 2 additions and 4 deletions.
diff --git a/puzzlefs-lib/src/format/types.rs b/puzzlefs-lib/src/format/types.rs
@@ -794,10 +794,8 @@ impl Serialize for Digest {
 impl TryFrom<&str> for Digest {
     type Error = FromHexError;
     fn try_from(s: &str) -> std::result::Result<Self, Self::Error> {
-        let digest = hex::decode(s)?;
-        let digest: [u8; SHA256_BLOCK_SIZE] = digest
-            .try_into()
-            .map_err(|_| FromHexError::InvalidStringLength)?;
+        let mut digest: [u8; SHA256_BLOCK_SIZE] = [0; SHA256_BLOCK_SIZE];
+        hex::decode_to_slice(s, &mut digest)?;
         Ok(Digest(digest))
     }
 }