From a1f2366fe8be24908a3ed3de1df1184912c8a25f Mon Sep 17 00:00:00 2001
From: collin <collin.chin@berkeley.edu>
Date: Tue, 14 Jul 2020 17:37:04 -0700
Subject: [PATCH] add evaluate eq gadget for i types

---
 gadgets/src/signed_integer/arithmetic/cmp.rs | 13 -------
 gadgets/src/signed_integer/arithmetic/mod.rs |  3 --
 gadgets/src/signed_integer/mod.rs            |  3 ++
 gadgets/src/signed_integer/relational/eq.rs  | 40 ++++++++++++++++++++
 gadgets/src/signed_integer/relational/mod.rs |  2 +
 5 files changed, 45 insertions(+), 16 deletions(-)
 delete mode 100644 gadgets/src/signed_integer/arithmetic/cmp.rs
 create mode 100644 gadgets/src/signed_integer/relational/eq.rs
 create mode 100644 gadgets/src/signed_integer/relational/mod.rs

diff --git a/gadgets/src/signed_integer/arithmetic/cmp.rs b/gadgets/src/signed_integer/arithmetic/cmp.rs
deleted file mode 100644
index d198a88596..0000000000
--- a/gadgets/src/signed_integer/arithmetic/cmp.rs
+++ /dev/null
@@ -1,13 +0,0 @@
-use crate::errors::IntegerError;
-
-use snarkos_models::{
-    curves::PrimeField,
-    gadgets::{r1cs::ConstraintSystem, utilities::boolean::Boolean},
-};
-
-///
-pub trait Cmp<Rhs = Self>
-where
-    Self: std::marker::Sized,
-{
-}
diff --git a/gadgets/src/signed_integer/arithmetic/mod.rs b/gadgets/src/signed_integer/arithmetic/mod.rs
index 6cd0f3bc66..ae4970b62e 100644
--- a/gadgets/src/signed_integer/arithmetic/mod.rs
+++ b/gadgets/src/signed_integer/arithmetic/mod.rs
@@ -2,9 +2,6 @@
 pub mod add;
 pub use self::add::*;
 
-pub mod cmp;
-pub use self::cmp::*;
-
 pub mod div;
 pub use self::div::*;
 
diff --git a/gadgets/src/signed_integer/mod.rs b/gadgets/src/signed_integer/mod.rs
index 53c20da0b5..99a2192182 100644
--- a/gadgets/src/signed_integer/mod.rs
+++ b/gadgets/src/signed_integer/mod.rs
@@ -6,5 +6,8 @@ pub use self::arithmetic::*;
 pub mod int_impl;
 pub use self::int_impl::*;
 
+pub mod relational;
+pub use self::relational::*;
+
 pub mod utilities;
 pub use self::utilities::*;
diff --git a/gadgets/src/signed_integer/relational/eq.rs b/gadgets/src/signed_integer/relational/eq.rs
new file mode 100644
index 0000000000..68deca71ed
--- /dev/null
+++ b/gadgets/src/signed_integer/relational/eq.rs
@@ -0,0 +1,40 @@
+use crate::{Int, Int128, Int16, Int32, Int64, Int8};
+
+use snarkos_errors::gadgets::SynthesisError;
+use snarkos_models::{
+    curves::PrimeField,
+    gadgets::{
+        r1cs::ConstraintSystem,
+        utilities::{boolean::Boolean, eq::EvaluateEqGadget},
+    },
+};
+
+macro_rules! eq_gadget_impl {
+    ($($gadget: ident)*) => ($(
+        impl<F: PrimeField> EvaluateEqGadget<F> for $gadget {
+            fn evaluate_equal<CS: ConstraintSystem<F>>(
+                &self,
+                mut cs: CS,
+                other: &Self
+            ) -> Result<Boolean, SynthesisError> {
+                let mut result = Boolean::constant(true);
+                for (i, (a, b)) in self.bits.iter().zip(&other.bits).enumerate() {
+                    let equal = a.evaluate_equal(
+                        &mut cs.ns(|| format!("{} evaluate equality for {}-th bit", <$gadget as Int>::SIZE, i)),
+                        b,
+                    )?;
+
+                    result = Boolean::and(
+                        &mut cs.ns(|| format!("{} and result for {}-th bit", <$gadget as Int>::SIZE, i)),
+                        &equal,
+                        &result,
+                    )?;
+                }
+
+                Ok(result)
+            }
+        }
+    )*)
+}
+
+eq_gadget_impl!(Int8 Int16 Int32 Int64 Int128);
diff --git a/gadgets/src/signed_integer/relational/mod.rs b/gadgets/src/signed_integer/relational/mod.rs
new file mode 100644
index 0000000000..9d43347649
--- /dev/null
+++ b/gadgets/src/signed_integer/relational/mod.rs
@@ -0,0 +1,2 @@
+pub mod eq;
+pub use self::eq::*;