From 4092d473944bf129b0d0bd5991276c4fba4053ec Mon Sep 17 00:00:00 2001
From: Kevaundray Wedderburn <kevtheappdev@gmail.com>
Date: Thu, 1 Apr 2021 20:58:21 +0100
Subject: [PATCH] ACIR

- Add helper methods, for converting between ACIR and R1CS
---
 crates/acir/src/circuit/gate.rs         | 14 ++++++++++++++
 crates/acir/src/circuit/mod.rs          | 10 ++++++++++
 crates/acir/src/native_types/witness.rs |  5 +++++
 3 files changed, 29 insertions(+)

diff --git a/crates/acir/src/circuit/gate.rs b/crates/acir/src/circuit/gate.rs
index 0ffce7b89fa..fdab36c5650 100644
--- a/crates/acir/src/circuit/gate.rs
+++ b/crates/acir/src/circuit/gate.rs
@@ -28,6 +28,20 @@ pub enum Gate {
     Directive(Directive),
 }
 
+impl Gate {
+    pub fn is_arithmetic(&self) -> bool {
+        if let Gate::Arithmetic(_) = self {
+            true
+        } else { false}
+    }
+    pub fn arithmetic(self) -> Arithmetic {
+        match self {
+            Gate::Arithmetic(gate) => gate,
+            _=> panic!("tried to convert a non arithmetic gate to an Arithmetic struct")
+        }
+    }
+}
+
 #[derive(Clone, Debug)]
 /// Directives do not apply any constraints.
 pub enum Directive {
diff --git a/crates/acir/src/circuit/mod.rs b/crates/acir/src/circuit/mod.rs
index f741677670e..fdf764b0502 100644
--- a/crates/acir/src/circuit/mod.rs
+++ b/crates/acir/src/circuit/mod.rs
@@ -12,6 +12,12 @@ pub struct Circuit {
     pub public_inputs: PublicInputs,
 }
 
+impl Circuit {
+    pub fn num_vars(&self) -> u32 {
+        self.current_witness_index + 1
+    }
+}
+
 #[derive(Clone, Debug)]
 pub struct PublicInputs(pub Vec<Witness>);
 
@@ -23,6 +29,10 @@ impl PublicInputs {
             .map(|witness| witness.witness_index() as u32)
             .collect()
     }
+
+    pub fn contains(&self, index : usize) -> bool {
+        self.0.contains(&Witness(index as u32))
+    }
 }
 #[derive(Clone, Debug)]
 pub struct Selector(pub String, pub FieldElement);
diff --git a/crates/acir/src/native_types/witness.rs b/crates/acir/src/native_types/witness.rs
index 36d2fa8d4dd..a706d7ac862 100644
--- a/crates/acir/src/native_types/witness.rs
+++ b/crates/acir/src/native_types/witness.rs
@@ -15,6 +15,11 @@ impl Witness {
     pub fn witness_index(&self) -> u32 {
         self.0
     }
+    pub fn as_usize(&self) -> usize {
+        // This is safe as long as the architecture is 32bits minimum
+        self.0 as usize
+    }
+
 
     pub const fn can_defer_constraint(&self) -> bool {
         true