From ccada7e1a162d08d83db949880db17012d230973 Mon Sep 17 00:00:00 2001
From: moana <moana@dusk.network>
Date: Fri, 9 Aug 2024 15:42:08 +0200
Subject: [PATCH] circuit: Fixes for #232

---
 circuits/CHANGELOG.md           |  2 ++
 circuits/src/lib.rs             | 11 +++++++----
 circuits/tests/serialization.rs | 12 ++++++------
 3 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/circuits/CHANGELOG.md b/circuits/CHANGELOG.md
index a586b8a..00d7431 100644
--- a/circuits/CHANGELOG.md
+++ b/circuits/CHANGELOG.md
@@ -31,6 +31,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Add `Serializable` trait implementation for `OutputNoteInfo` [#232]
 - Add `Clone` and `PartialEq` derives for `TxCircuit` [#232]
 - Add `PartialEq` derive for `InputNoteInfo` [#232]
+- Add associated const `TxCircuit::SIZE`
+- Add associated const `InputNoteInfo::SIZE`
 - Add `PartialEq` derive for `OutputNoteInfo` [#232]
 - Add `dusk-bls12_381` dependency [#235]
 - Add `"plonk"` feature to add the `dusk-plonk` dependency [#235]
diff --git a/circuits/src/lib.rs b/circuits/src/lib.rs
index 2dae245..45c32b9 100644
--- a/circuits/src/lib.rs
+++ b/circuits/src/lib.rs
@@ -54,7 +54,8 @@ pub struct TxCircuit<const H: usize, const I: usize> {
 }
 
 impl<const H: usize, const I: usize> TxCircuit<H, I> {
-    const SIZE: usize = I * InputNoteInfo::<H>::SIZE
+    /// The size of a `TxCircuit`.
+    pub const SIZE: usize = I * InputNoteInfo::<H>::SIZE
         + OUTPUT_NOTES * OutputNoteInfo::SIZE
         + 2 * BlsScalar::SIZE
         + 2 * u64::SIZE
@@ -102,8 +103,9 @@ impl<const H: usize, const I: usize> TxCircuit<H, I> {
         }
 
         let mut input_notes_info = Vec::new();
-        for _ in 0..I {
-            input_notes_info.push(InputNoteInfo::from_slice(bytes)?);
+        for i in 0..I {
+            let start = i * InputNoteInfo::<H>::SIZE;
+            input_notes_info.push(InputNoteInfo::from_slice(&bytes[start..])?);
         }
 
         let mut reader = &bytes[I * InputNoteInfo::<H>::SIZE..];
@@ -217,7 +219,8 @@ pub struct InputNoteInfo<const H: usize> {
 }
 
 impl<const H: usize> InputNoteInfo<H> {
-    const SIZE: usize = (1 + H * ARITY) * Item::SIZE
+    /// The size of an `InputNoteInfo`
+    pub const SIZE: usize = (1 + H * ARITY) * Item::SIZE
         + H * (u32::BITS as usize / 8)
         + Note::SIZE
         + JubJubAffine::SIZE
diff --git a/circuits/tests/serialization.rs b/circuits/tests/serialization.rs
index 22a99bd..c7ba98c 100644
--- a/circuits/tests/serialization.rs
+++ b/circuits/tests/serialization.rs
@@ -39,12 +39,12 @@ fn tx_ciruit_1_2() -> Result<(), BytesError> {
 fn tx_ciruit_2_2() -> Result<(), BytesError> {
     let mut rng = StdRng::seed_from_u64(0xbeef);
 
-    let circuit = random_circuit::<1>(&mut rng);
+    let circuit = random_circuit::<2>(&mut rng);
     let circuit_bytes = circuit.to_var_bytes();
 
     assert_eq!(
         circuit,
-        TxCircuit::<HEIGHT, 1>::from_slice(&circuit_bytes[..])?
+        TxCircuit::<HEIGHT, 2>::from_slice(&circuit_bytes[..])?
     );
 
     Ok(())
@@ -54,12 +54,12 @@ fn tx_ciruit_2_2() -> Result<(), BytesError> {
 fn tx_ciruit_3_2() -> Result<(), BytesError> {
     let mut rng = StdRng::seed_from_u64(0xbeef);
 
-    let circuit = random_circuit::<1>(&mut rng);
+    let circuit = random_circuit::<3>(&mut rng);
     let circuit_bytes = circuit.to_var_bytes();
 
     assert_eq!(
         circuit,
-        TxCircuit::<HEIGHT, 1>::from_slice(&circuit_bytes[..])?
+        TxCircuit::<HEIGHT, 3>::from_slice(&circuit_bytes[..])?
     );
 
     Ok(())
@@ -69,12 +69,12 @@ fn tx_ciruit_3_2() -> Result<(), BytesError> {
 fn tx_ciruit_4_2() -> Result<(), BytesError> {
     let mut rng = StdRng::seed_from_u64(0xbeef);
 
-    let circuit = random_circuit::<1>(&mut rng);
+    let circuit = random_circuit::<4>(&mut rng);
     let circuit_bytes = circuit.to_var_bytes();
 
     assert_eq!(
         circuit,
-        TxCircuit::<HEIGHT, 1>::from_slice(&circuit_bytes[..])?
+        TxCircuit::<HEIGHT, 4>::from_slice(&circuit_bytes[..])?
     );
 
     Ok(())