From eca28fd3e8b6198e3d994ca258f34068e57b8434 Mon Sep 17 00:00:00 2001
From: Henry de Valence <hdevalence@hdevalence.ca>
Date: Tue, 28 Feb 2017 19:08:37 -0800
Subject: [PATCH] Refactor Scalar::hash_from_bytes to allow streaming input to
 the hash.

---
 src/scalar.rs | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/scalar.rs b/src/scalar.rs
index f7808e3..62e6183 100644
--- a/src/scalar.rs
+++ b/src/scalar.rs
@@ -173,6 +173,8 @@ impl Scalar {
     /// Takes a type parameter `D`, which is any `Digest` producing 64
     /// bytes (512 bits) of output.
     ///
+    /// Convenience wrapper around `from_hash`.
+    ///
     /// # Example
     ///
     /// ```
@@ -193,6 +195,16 @@ impl Scalar {
             where D: Digest<OutputSize=U64> + Default {
         let mut hash = D::default();
         hash.input(input);
+        Scalar::from_hash(hash)
+    }
+
+    /// Construct a scalar from an existing `Digest` instance.
+    ///
+    /// Use this instead of `hash_from_bytes` if it is more convenient
+    /// to stream data into the `Digest` than to pass a single byte
+    /// slice.
+    pub fn from_hash<D>(hash: D) -> Scalar
+            where D: Digest<OutputSize=U64> + Default {
         // XXX this seems clumsy
         let mut output = [0u8;64];
         output.copy_from_slice(hash.result().as_slice());