optimize sha256 interface gather/vector inputs

Signed-off-by: Jason Volk <jason@zemos.net>

src/core/utils/hash/sha256.rs

@@ -1,9 +1,62 @@
-use ring::{digest, digest::SHA256};
+use ring::{
+	digest,
+	digest::{Context, SHA256, SHA256_OUTPUT_LEN},
+};
 
-#[tracing::instrument(skip_all, level = "debug")]
-pub(super) fn hash(keys: &[&[u8]]) -> Vec<u8> {
-	// We only hash the pdu's event ids, not the whole pdu
-	let bytes = keys.join(&0xFF);
-	let hash = digest::digest(&SHA256, &bytes);
-	hash.as_ref().to_owned()
+pub type Digest = [u8; SHA256_OUTPUT_LEN];
+
+/// Sha256 hash (input gather joined by 0xFF bytes)
+#[must_use]
+#[tracing::instrument(skip(inputs), level = "trace")]
+pub fn delimited<'a, T, I>(mut inputs: I) -> Digest
+where
+	I: Iterator<Item = T> + 'a,
+	T: AsRef<[u8]> + 'a,
+{
+	let mut ctx = Context::new(&SHA256);
+	if let Some(input) = inputs.next() {
+		ctx.update(input.as_ref());
+		for input in inputs {
+			ctx.update(b"\xFF");
+			ctx.update(input.as_ref());
+		}
+	}
+
+	ctx.finish()
+		.as_ref()
+		.try_into()
+		.expect("failed to return Digest buffer")
+}
+
+/// Sha256 hash (input gather)
+#[must_use]
+#[tracing::instrument(skip(inputs), level = "trace")]
+pub fn concat<'a, T, I>(inputs: I) -> Digest
+where
+	I: Iterator<Item = T> + 'a,
+	T: AsRef<[u8]> + 'a,
+{
+	inputs
+		.fold(Context::new(&SHA256), |mut ctx, input| {
+			ctx.update(input.as_ref());
+			ctx
+		})
+		.finish()
+		.as_ref()
+		.try_into()
+		.expect("failed to return Digest buffer")
+}
+
+/// Sha256 hash
+#[inline]
+#[must_use]
+#[tracing::instrument(skip(input), level = "trace")]
+pub fn hash<T>(input: T) -> Digest
+where
+	T: AsRef<[u8]>,
+{
+	digest::digest(&SHA256, input.as_ref())
+		.as_ref()
+		.try_into()
+		.expect("failed to return Digest buffer")
 }