move comparator into leo-gadgets. impl cmp for i types

Cargo.lock

@@ -580,6 +580,7 @@ dependencies = [
  "bincode",
  "hex",
  "leo-ast",
+ "leo-gadgets",
  "leo-inputs",
  "leo-types",
  "log",

compiler/Cargo.toml

@@ -6,8 +6,9 @@ edition = "2018"
 
 [dependencies]
 leo-ast = { path = "../ast", version = "0.1.0" }
-leo-types = { path = "../types", version = "0.1.0" }
+leo-gadgets = { path = "../gadgets", version = "0.1.0" }
 leo-inputs = { path = "../leo-inputs", version = "0.1.0" }
+leo-types = { path = "../types", version = "0.1.0" }
 
 snarkos-curves = { git = "ssh://git@github.com/AleoHQ/snarkOS.git", rev = "c7a56d9", default-features = false }
 snarkos-dpc = { git = "ssh://git@github.com/AleoHQ/snarkOS.git", rev = "c7a56d9", default-features = false }

compiler/src/expression/relational/ge.rs

@@ -1,6 +1,7 @@
 //! Enforces a relational `>=` operator in a resolved Leo program.
 
-use crate::{comparator::ComparatorGadget, errors::ExpressionError, value::ConstrainedValue, GroupType};
+use crate::{errors::ExpressionError, value::ConstrainedValue, GroupType};
+use leo_gadgets::binary::ComparatorGadget;
 use leo_types::Span;
 
 use snarkos_models::{

compiler/src/expression/relational/gt.rs

@@ -1,6 +1,7 @@
 //! Enforces a relational `>` operator in a resolved Leo program.
 
-use crate::{comparator::ComparatorGadget, errors::ExpressionError, value::ConstrainedValue, GroupType};
+use crate::{errors::ExpressionError, value::ConstrainedValue, GroupType};
+use leo_gadgets::binary::ComparatorGadget;
 use leo_types::Span;
 
 use snarkos_models::{

compiler/src/expression/relational/le.rs

@@ -1,6 +1,7 @@
 //! Enforces a relational `<=` operator in a resolved Leo program.
 
-use crate::{comparator::ComparatorGadget, errors::ExpressionError, value::ConstrainedValue, GroupType};
+use crate::{errors::ExpressionError, value::ConstrainedValue, GroupType};
+use leo_gadgets::binary::ComparatorGadget;
 use leo_types::Span;
 
 use snarkos_models::{

compiler/src/expression/relational/lt.rs

@@ -1,6 +1,7 @@
 //! Enforces a relational `<` operator in a resolved Leo program.
 
-use crate::{comparator::EvaluateLtGadget, errors::ExpressionError, value::ConstrainedValue, GroupType};
+use crate::{errors::ExpressionError, value::ConstrainedValue, GroupType};
+use leo_gadgets::binary::comparator::EvaluateLtGadget;
 use leo_types::Span;
 
 use snarkos_models::{

compiler/src/value/field/field_type.rs

@@ -1,9 +1,7 @@
 //! A data type that represents a field value
 
-use crate::{
-    comparator::{ComparatorGadget, EvaluateLtGadget},
-    errors::FieldError,
-};
+use crate::errors::FieldError;
+use leo_gadgets::binary::{ComparatorGadget, EvaluateLtGadget};
 use leo_types::Span;
 
 use snarkos_errors::gadgets::SynthesisError;

compiler/src/value/integer.rs

@@ -1,8 +1,6 @@
 //! Conversion of integer declarations to constraints in Leo.
-use crate::{
-    comparator::{ComparatorGadget, EvaluateLtGadget},
-    errors::IntegerError,
-};
+use crate::errors::IntegerError;
+use leo_gadgets::binary::comparator::{ComparatorGadget, EvaluateLtGadget};
 use leo_types::{InputValue, IntegerType, Span};
 
 use snarkos_errors::gadgets::SynthesisError;

compiler/src/value/mod.rs

@@ -5,8 +5,6 @@ pub use self::address::*;
 
 pub mod boolean;
 
-pub(crate) mod comparator;
-
 pub mod field;
 pub use self::field::*;
 

gadgets/src/binary/mod.rs

@@ -2,5 +2,8 @@
 pub mod adder;
 pub use self::adder::*;
 
+pub mod comparator;
+pub use self::comparator::*;
+
 pub mod rca;
 pub use self::rca::*;

gadgets/src/signed_integer/relational/lt.rs

@@ -0,0 +1,70 @@
+use crate::{
+    binary::{ComparatorGadget, EvaluateLtGadget},
+    Int128,
+    Int16,
+    Int32,
+    Int64,
+    Int8,
+};
+
+use snarkos_errors::gadgets::SynthesisError;
+use snarkos_models::{
+    curves::PrimeField,
+    gadgets::{r1cs::ConstraintSystem, utilities::boolean::Boolean},
+};
+
+macro_rules! cmp_gadget_impl {
+    ($($gadget: ident)*) => ($(
+        impl<F: PrimeField> EvaluateLtGadget<F> for $gadget {
+            fn less_than<CS: ConstraintSystem<F>>(
+                &self,
+                mut cs: CS,
+                other: &Self
+            ) -> Result<Boolean, SynthesisError> {
+
+                for (i, (a, b)) in self.bits
+                    .iter()
+                    .rev()
+                    .zip(other.bits.iter().rev())
+                    .enumerate()
+                {
+                    let is_greater = if i == 0 {
+                        // Check sign bit
+                        // is_greater = !a_msb & b_msb
+                        // only true when a > b
+                        Boolean::and(cs.ns(|| format!("not a and b [{}]", i)), &a.not(), b)?
+                    } else {
+                        // is_greater = a & !b
+                        // only true when a > b
+                        Boolean::and(cs.ns(|| format!("a and not b [{}]", i)), a, &b.not())?
+                    };
+
+                    let is_less = if i == 0 {
+                        // Check sign bit
+                        // is_less = a_msb & ! b_msb
+                        // only true when a < b
+                        Boolean::and(cs.ns(|| format!("a and not b [{}]", i)), a, &b.not())?
+                    } else {
+                        // is_less = !a & b
+                        // only true when a < b
+                        Boolean::and(cs.ns(|| format!("not a and b [{}]", i)), &a.not(), b)?
+                    };
+
+                    if is_greater.get_value().unwrap() {
+                        return Ok(is_greater.not());
+                    } else if is_less.get_value().unwrap() {
+                        return Ok(is_less);
+                    } else if i == self.bits.len() - 1 {
+                        return Ok(is_less);
+                    }
+                }
+
+                Err(SynthesisError::Unsatisfiable)
+            }
+        }
+
+        impl<F: PrimeField> ComparatorGadget<F> for $gadget {}
+    )*)
+}
+
+cmp_gadget_impl!(Int8 Int16 Int32 Int64 Int128);

gadgets/src/signed_integer/relational/mod.rs

@@ -1,2 +1,6 @@
+#[macro_use]
 pub mod eq;
 pub use self::eq::*;
+
+pub mod lt;
+pub use self::lt::*;