chore: move some nr utils around

noir-projects/aztec-nr/aztec/src/keys/point_to_symmetric_key.nr

@@ -1,18 +1,19 @@
 use crate::utils::point::point_to_bytes;
-use dep::protocol_types::{
-    constants::GENERATOR_INDEX__SYMMETRIC_KEY, point::Point, scalar::Scalar, utils::arr_copy_slice,
-};
+use dep::protocol_types::{constants::GENERATOR_INDEX__SYMMETRIC_KEY, point::Point, scalar::Scalar};
 use std::{embedded_curve_ops::multi_scalar_mul, hash::sha256};
 
 // TODO(#5726): This function is called deriveAESSecret in TS. I don't like point_to_symmetric_key name much since
 // point is not the only input of the function. Unify naming with TS once we have a better name.
 pub fn point_to_symmetric_key(secret: Scalar, point: Point) -> [u8; 32] {
-    let shared_secret: Point = multi_scalar_mul([point], [secret]);
-    let shared_secret = point_to_bytes(shared_secret);
-    let mut shared_secret_bytes_with_separator = [0 as u8; 33];
-    shared_secret_bytes_with_separator =
-        arr_copy_slice(shared_secret, shared_secret_bytes_with_separator, 0);
+    let shared_secret = point_to_bytes(multi_scalar_mul([point], [secret]));
+
+    let mut shared_secret_bytes_with_separator: [u8; 33] = std::mem::zeroed();
+    for i in 0..shared_secret.len() {
+        shared_secret_bytes_with_separator[i] = shared_secret[i];
+    }
+
     shared_secret_bytes_with_separator[32] = GENERATOR_INDEX__SYMMETRIC_KEY;
+
     sha256(shared_secret_bytes_with_separator)
 }
 

noir-projects/aztec-nr/aztec/src/note/note_getter/mod.nr

@@ -141,7 +141,7 @@ where
     let filter_args = options.filter_args;
     let filtered_notes = filter_fn(opt_notes, filter_args);
 
-    let notes = crate::utils::collapse_array(filtered_notes);
+    let notes = crate::utils::array::collapse(filtered_notes);
     let mut note_hashes: BoundedVec<Field, MAX_NOTE_HASH_READ_REQUESTS_PER_CALL> =
         BoundedVec::new();
 

noir-projects/aztec-nr/aztec/src/note/utils.nr

@@ -1,15 +1,12 @@
 use crate::{
     context::PrivateContext,
     note::{note_header::NoteHeader, note_interface::{NoteInterface, NullifiableNote}},
+    utils::array,
 };
 
-use dep::protocol_types::{
-    hash::{
-        compute_siloed_note_hash as compute_siloed_note_hash,
-        compute_siloed_nullifier as compute_siloed_nullifier_from_preimage,
-        compute_unique_note_hash,
-    },
-    utils::arr_copy_slice,
+use dep::protocol_types::hash::{
+    compute_siloed_note_hash as compute_siloed_note_hash,
+    compute_siloed_nullifier as compute_siloed_nullifier_from_preimage, compute_unique_note_hash,
 };
 
 pub fn compute_siloed_nullifier<Note, let N: u32>(
@@ -128,7 +125,7 @@ pub unconstrained fn compute_note_hash_and_optionally_a_nullifier<T, let N: u32,
 where
     T: NoteInterface<N> + NullifiableNote,
 {
-    let mut note = deserialize_content(arr_copy_slice(serialized_note, [0; N], 0));
+    let mut note = deserialize_content(array::subarray(serialized_note, 0));
     note.set_header(note_header);
 
     let note_hash = note.compute_note_hash();

noir-projects/aztec-nr/aztec/src/oracle/get_l1_to_l2_membership_witness.nr

@@ -1,6 +1,5 @@
-use dep::protocol_types::{
-    address::AztecAddress, constants::L1_TO_L2_MSG_TREE_HEIGHT, utils::arr_copy_slice,
-};
+use crate::utils::array;
+use dep::protocol_types::{address::AztecAddress, constants::L1_TO_L2_MSG_TREE_HEIGHT};
 
 /// Returns the leaf index and sibling path of an entry in the L1 to L2 messaging tree, which can then be used to prove
 /// its existence.
@@ -12,7 +11,7 @@ pub unconstrained fn get_l1_to_l2_membership_witness(
     let returned_message =
         get_l1_to_l2_membership_witness_oracle(contract_address, message_hash, secret);
     let leaf_index = returned_message[0];
-    let sibling_path = arr_copy_slice(returned_message, [0; L1_TO_L2_MSG_TREE_HEIGHT], 1);
+    let sibling_path = array::subarray(returned_message, 1);
 
     (leaf_index, sibling_path)
 }

noir-projects/aztec-nr/aztec/src/oracle/get_membership_witness.nr

@@ -1,7 +1,5 @@
-use dep::protocol_types::{
-    constants::{ARCHIVE_HEIGHT, NOTE_HASH_TREE_HEIGHT},
-    utils::arr_copy_slice,
-};
+use crate::utils::array;
+use dep::protocol_types::constants::{ARCHIVE_HEIGHT, NOTE_HASH_TREE_HEIGHT};
 
 global NOTE_HASH_TREE_ID: Field = 1;
 global ARCHIVE_TREE_ID: Field = 4;
@@ -31,7 +29,7 @@ pub unconstrained fn get_membership_witness<let N: u32, let M: u32>(
     leaf_value: Field,
 ) -> MembershipWitness<N, M> {
     let fields: [Field; M] = get_membership_witness_oracle(block_number, tree_id, leaf_value);
-    MembershipWitness { index: fields[0], path: arr_copy_slice(fields, [0; N], 1) }
+    MembershipWitness { index: fields[0], path: array::subarray(fields, 1) }
 }
 
 // Note: get_nullifier_membership_witness function is implemented in get_nullifier_membership_witness.nr

noir-projects/aztec-nr/aztec/src/oracle/get_nullifier_membership_witness.nr

@@ -1,7 +1,6 @@
+use crate::utils::array;
 use dep::protocol_types::{
-    abis::nullifier_leaf_preimage::{NULLIFIER_LEAF_PREIMAGE_LENGTH, NullifierLeafPreimage},
-    constants::NULLIFIER_TREE_HEIGHT,
-    utils::arr_copy_slice,
+    abis::nullifier_leaf_preimage::NullifierLeafPreimage, constants::NULLIFIER_TREE_HEIGHT,
 };
 
 // INDEX_LENGTH + NULLIFIER_LEAF_PREIMAGE_LENGTH + NULLIFIER_TREE_HEIGHT
@@ -15,15 +14,12 @@ pub struct NullifierMembershipWitness {
 
 impl NullifierMembershipWitness {
     pub fn deserialize(fields: [Field; NULLIFIER_MEMBERSHIP_WITNESS]) -> Self {
-        let leaf_preimage_fields = arr_copy_slice(fields, [0; NULLIFIER_LEAF_PREIMAGE_LENGTH], 1);
+        let serialized_leaf_preimage = array::subarray(fields, 1);
+
         Self {
             index: fields[0],
-            leaf_preimage: NullifierLeafPreimage::deserialize(leaf_preimage_fields),
-            path: arr_copy_slice(
-                fields,
-                [0; NULLIFIER_TREE_HEIGHT],
-                1 + NULLIFIER_LEAF_PREIMAGE_LENGTH,
-            ),
+            leaf_preimage: NullifierLeafPreimage::deserialize(serialized_leaf_preimage),
+            path: array::subarray(fields, 1 + serialized_leaf_preimage.len()),
         }
     }
 }

noir-projects/aztec-nr/aztec/src/oracle/get_public_data_witness.nr

@@ -1,6 +1,5 @@
-use dep::protocol_types::{
-    constants::PUBLIC_DATA_TREE_HEIGHT, data::PublicDataTreeLeafPreimage, utils::arr_copy_slice,
-};
+use crate::utils::array;
+use dep::protocol_types::{constants::PUBLIC_DATA_TREE_HEIGHT, data::PublicDataTreeLeafPreimage};
 
 global LEAF_PREIMAGE_LENGTH: u32 = 4;
 global PUBLIC_DATA_WITNESS: u32 = 45;
@@ -30,10 +29,6 @@ pub unconstrained fn get_public_data_witness(
             next_index: fields[3] as u32,
             next_slot: fields[4],
         },
-        path: arr_copy_slice(
-            fields,
-            [0; PUBLIC_DATA_TREE_HEIGHT],
-            1 + LEAF_PREIMAGE_LENGTH,
-        ),
+        path: array::subarray(fields, 1 + LEAF_PREIMAGE_LENGTH),
     }
 }

noir-projects/aztec-nr/aztec/src/oracle/notes.nr

@@ -1,9 +1,8 @@
-use crate::note::{note_header::NoteHeader, note_interface::NoteInterface};
+use crate::{note::{note_header::NoteHeader, note_interface::NoteInterface}, utils::array};
 
 use dep::protocol_types::{
     address::AztecAddress,
     indexed_tagging_secret::{INDEXED_TAGGING_SECRET_LENGTH, IndexedTaggingSecret},
-    utils::arr_copy_slice,
 };
 
 /// Notifies the simulator that a note has been created, so that it can be returned in future read requests in the same
@@ -181,12 +180,14 @@ where
             let return_header_length: u32 = 2; // num_notes & contract_address.
             let extra_preimage_length: u32 = 2; // nonce & note_hash_counter.
             let read_offset: u32 = return_header_length + i * (N + extra_preimage_length);
+
             let nonce = fields[read_offset];
             let note_hash_counter = fields[read_offset + 1] as u32;
-            let header = NoteHeader { contract_address, nonce, storage_slot, note_hash_counter };
-            let serialized_note = arr_copy_slice(fields, [0; N], read_offset + 2);
-            let mut note = Note::deserialize_content(serialized_note);
-            note.set_header(header);
+            let note_content = array::subarray(fields, read_offset + 2);
+
+            let mut note = Note::deserialize_content(note_content);
+            note.set_header(NoteHeader { contract_address, nonce, storage_slot, note_hash_counter });
+
             placeholder_opt_notes[i] = Option::some(note);
         };
     }