added comments related to commitments

nssa/core/src/commitment.rs

@@ -8,6 +8,8 @@ use crate::{NullifierPublicKey, account::Account};
 pub struct Commitment(pub(super) [u8; 32]);
 
 impl Commitment {
+    //generate new commitment to a private account owned by user with npk.
+    //hash(npk || program_owner || balance || nonce || data)
     pub fn new(npk: &NullifierPublicKey, account: &Account) -> Self {
         let mut bytes = Vec::new();
         bytes.extend_from_slice(&npk.to_byte_array());
@@ -34,6 +36,8 @@ pub type CommitmentSetDigest = [u8; 32];
 
 pub type MembershipProof = (usize, Vec<[u8; 32]>);
 
+/// computes the resulting digest/root hash for a membership proof
+/// and its corresponding commitment.
 pub fn compute_digest_for_path(
     commitment: &Commitment,
     proof: &MembershipProof,

nssa/src/state.rs

@@ -21,6 +21,7 @@ impl CommitmentSet {
         self.merkle_tree.root()
     }
 
+    /// queries the CommitmentSet for membership proof of commitment
     pub fn get_proof_for(&self, commitment: &Commitment) -> Option<MembershipProof> {
         let index = *self.commitments.get(commitment)?;
 
@@ -29,6 +30,7 @@ impl CommitmentSet {
             .map(|path| (index, path))
     }
 
+    /// appends a list of commitments to the CommitmentSet.
     pub(crate) fn extend(&mut self, commitments: &[Commitment]) {
         for commitment in commitments.iter().cloned() {
             let index = self.merkle_tree.insert(commitment.to_byte_array());
@@ -41,6 +43,9 @@ impl CommitmentSet {
         self.commitments.contains_key(commitment)
     }
 
+    /// Initializes a CommitmentState with a given capacity.
+    /// if capacity is not a power_of_two, then capacity is taken
+    /// to be the next power_of_two.
     pub(crate) fn with_capacity(capacity: usize) -> CommitmentSet {
         Self {
             merkle_tree: MerkleTree::with_capacity(capacity),