conditional compilation with specialization feature

achimcc · Nov 30, 2022 · c394b07 · c394b07
1 parent d996417
commit c394b07
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Showing 2 changed files with 12 additions and 9 deletions.
diff --git a/ec/src/models/short_weierstrass/group.rs b/ec/src/models/short_weierstrass/group.rs
@@ -634,7 +634,16 @@ impl<P: SWCurveConfig> ScalarMul for Projective<P> {
     }
 }
 
-impl<P: SWCurveConfig> VariableBaseMSM for Projective<P> {
+#[cfg(feature = "specialization")]
+pub trait CustomMSM: SWCurveConfig {
+    fn msm_bigint(
+        bases: &[Affine<Self>],
+        bigints: &[<Self::ScalarField as PrimeField>::BigInt],
+    ) -> Projective<Self>;
+}
+
+#[cfg(feature = "specialization")]
+impl<P: SWCurveConfig> VariableBaseMSM for Projective<P> where P: CustomMSM {
     fn msm_bigint(
         bases: &[Self::MulBase],
         bigints: &[<Self::ScalarField as PrimeField>::BigInt],
@@ -643,6 +652,8 @@ impl<P: SWCurveConfig> VariableBaseMSM for Projective<P> {
     }
 }
 
+impl<P: SWCurveConfig> VariableBaseMSM for Projective<P> {}
+
 impl<P: SWCurveConfig, T: Borrow<Affine<P>>> core::iter::Sum<T> for Projective<P> {
     fn sum<I: Iterator<Item = T>>(iter: I) -> Self {
         iter.fold(Projective::zero(), |sum, x| sum + x.borrow())

diff --git a/ec/src/models/short_weierstrass/mod.rs b/ec/src/models/short_weierstrass/mod.rs
@@ -105,14 +105,6 @@ pub trait SWCurveConfig: super::CurveConfig {
         res
     }
 
-    /// Default implementation for multi scalar multiplication
-    fn msm_bigint(
-        bases: &[Affine<Self>],
-        bigints: &[<Self::ScalarField as PrimeField>::BigInt],
-    ) -> Projective<Self> {
-        VariableBaseMSM::msm_bigint(bases, bigints)
-    }
-
     /// If uncompressed, serializes both x and y coordinates as well as a bit for whether it is
     /// infinity. If compressed, serializes x coordinate with two bits to encode whether y is
     /// positive, negative, or infinity.