feat: extend Finterprint to support raw bytes and optimize for Hash (#1338)

Author: georgeh0

rust/utils/src/fingerprint.rs

@@ -30,7 +30,7 @@ impl serde::ser::Error for FingerprinterError {
     }
 }
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct Fingerprint(pub [u8; 16]);
 
 impl Fingerprint {
@@ -63,6 +63,14 @@ impl AsRef<[u8]> for Fingerprint {
     }
 }
 
+impl std::hash::Hash for Fingerprint {
+    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+        // Fingerprint is already evenly distributed, so we can just use the first few bytes.
+        const N: usize = size_of::<usize>();
+        state.write(&self.0[..N]);
+    }
+}
+
 impl Serialize for Fingerprint {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -101,6 +109,10 @@ impl Fingerprinter {
         value.serialize(self)
     }
 
+    pub fn write_raw_bytes(&mut self, bytes: &[u8]) {
+        self.hasher.update(bytes);
+    }
+
     fn write_type_tag(&mut self, tag: &str) {
         self.hasher.update(tag.as_bytes());
         self.hasher.update(b";");