From 098ff2ffca98774a0c963f52a9afb62c7d49d64f Mon Sep 17 00:00:00 2001
From: Henry de Valence <hdevalence@hdevalence.ca>
Date: Fri, 6 Jan 2017 12:26:43 -0500
Subject: [PATCH] Move CTAssignable trait to util.rs from curve.rs

---
 src/curve.rs | 11 ++---------
 src/util.rs  |  8 ++++++++
 2 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/src/curve.rs b/src/curve.rs
index 971cdb5..079907c 100644
--- a/src/curve.rs
+++ b/src/curve.rs
@@ -86,6 +86,7 @@ use constants;
 use field::FieldElement;
 use scalar::Scalar;
 use util::bytes_equal_ct;
+use util::CTAssignable;
 
 // ------------------------------------------------------------------------
 // Compressed points
@@ -282,15 +283,6 @@ impl Identity for PreComputedPoint {
 // Constant-time assignment
 // ------------------------------------------------------------------------
 
-/// Trait for items which can be conditionally assigned in constant time.
-pub trait CTAssignable {
-    /// If `choice == 1u8`, assign `other` to `self`.
-    /// Otherwise, leave `self` unchanged.  
-    /// Executes in constant time.
-    // XXX this trait should be extracted?
-    fn conditional_assign(&mut self, other: &Self, choice: u8);
-}
-
 impl CTAssignable for CachedPoint {
     fn conditional_assign(&mut self, other: &CachedPoint, choice: u8) {
         self.Y_plus_X.conditional_assign(&other.Y_plus_X, choice);
@@ -806,6 +798,7 @@ mod test {
     use test::Bencher;
     use field::FieldElement;
     use scalar::Scalar;
+    use util::CTAssignable;
     use constants;
     use super::*;
     use super::select_precomputed_point;
diff --git a/src/util.rs b/src/util.rs
index d94a853..1391ef8 100644
--- a/src/util.rs
+++ b/src/util.rs
@@ -11,6 +11,14 @@
 
 //! Utility functions and tools for constant-time comparisons.
 
+/// Trait for items which can be conditionally assigned in constant time.
+pub trait CTAssignable {
+    /// If `choice == 1u8`, assign `other` to `self`.
+    /// Otherwise, leave `self` unchanged.
+    /// Executes in constant time.
+    fn conditional_assign(&mut self, other: &Self, choice: u8);
+}
+
 /// Check equality of two bytes in constant time.
 ///
 /// # Return