From 3759fc8aabed815edc985f6d0e67894275e0324c Mon Sep 17 00:00:00 2001
From: Jack Grigg <jack@z.cash>
Date: Thu, 21 May 2020 11:58:57 +1200
Subject: [PATCH] group: Default implementation of
 CurveProjective::batch_normalize

For convenience. Implementations will usually override this to take
advantage of implementation-specific batching optimisations.
---
 bellman/src/groth16/tests/dummy_engine.rs | 8 --------
 group/src/lib.rs                          | 8 +++++++-
 2 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/bellman/src/groth16/tests/dummy_engine.rs b/bellman/src/groth16/tests/dummy_engine.rs
index e9dcb3a8f..22361d6b5 100644
--- a/bellman/src/groth16/tests/dummy_engine.rs
+++ b/bellman/src/groth16/tests/dummy_engine.rs
@@ -396,14 +396,6 @@ impl PrimeGroup for Fr {}
 impl CurveProjective for Fr {
     type Affine = Fr;
 
-    fn batch_normalize(p: &[Self], q: &mut [Self::Affine]) {
-        assert_eq!(p.len(), q.len());
-
-        for (p, q) in p.iter().zip(q.iter_mut()) {
-            *q = p.to_affine();
-        }
-    }
-
     fn to_affine(&self) -> Fr {
         *self
     }
diff --git a/group/src/lib.rs b/group/src/lib.rs
index e9b396bab..8837345f2 100644
--- a/group/src/lib.rs
+++ b/group/src/lib.rs
@@ -99,7 +99,13 @@ pub trait CurveProjective:
 
     /// Converts a batch of projective elements into affine elements. This function will
     /// panic if `p.len() != q.len()`.
-    fn batch_normalize(p: &[Self], q: &mut [Self::Affine]);
+    fn batch_normalize(p: &[Self], q: &mut [Self::Affine]) {
+        assert_eq!(p.len(), q.len());
+
+        for (p, q) in p.iter().zip(q.iter_mut()) {
+            *q = p.to_affine();
+        }
+    }
 
     /// Converts this element into its affine representation.
     fn to_affine(&self) -> Self::Affine;