refactor(RLN): use iterators instead of loops (#33)

* refactor(RLN): use iterators instead of loops
* fix(rln): cargo fmt
* fix(rln): cargo clippy: avoid Vec object creation

Co-authored-by: s1fr0 <28568419+s1fr0@users.noreply.github.com>

rln/src/circuit.rs

@@ -38,8 +38,8 @@ pub const TEST_RESOURCES_FOLDER: &str = "./resources/tree_height_20/";
 pub fn ZKEY(resources_folder: &str) -> Result<(ProvingKey<Bn254>, ConstraintMatrices<Fr>)> {
     let zkey_path = format!("{resources_folder}{ZKEY_FILENAME}");
     if Path::new(&zkey_path).exists() {
-        let mut file = File::open(&zkey_path).unwrap();
-        let proving_key_and_matrices = read_zkey(&mut file).unwrap();
+        let mut file = File::open(&zkey_path)?;
+        let proving_key_and_matrices = read_zkey(&mut file)?;
         Ok(proving_key_and_matrices)
     } else {
         Err(Error::new(ErrorKind::NotFound, "No proving key found!"))
@@ -57,7 +57,7 @@ pub fn VK(resources_folder: &str) -> Result<VerifyingKey<Bn254>> {
         verifying_key = vk_from_json(&vk_path);
         Ok(verifying_key)
     } else if Path::new(&zkey_path).exists() {
-        let (proving_key, _matrices) = ZKEY(resources_folder).unwrap();
+        let (proving_key, _matrices) = ZKEY(resources_folder)?;
         verifying_key = proving_key.vk;
         Ok(verifying_key)
     } else {

rln/src/protocol.rs

@@ -207,15 +207,19 @@ pub fn rln_witness_from_json(input_json_str: &str) -> RLNWitnessInput {
 
     let identity_secret = str_to_field(input_json["identity_secret"].to_string(), 10);
 
-    let mut path_elements: Vec<Field> = vec![];
-    for v in input_json["path_elements"].as_array().unwrap().iter() {
-        path_elements.push(str_to_field(v.to_string(), 10));
-    }
+    let path_elements = input_json["path_elements"]
+        .as_array()
+        .unwrap()
+        .iter()
+        .map(|v| str_to_field(v.to_string(), 10))
+        .collect();
 
-    let mut identity_path_index: Vec<u8> = vec![];
-    for v in input_json["identity_path_index"].as_array().unwrap().iter() {
-        identity_path_index.push(v.as_u64().unwrap() as u8);
-    }
+    let identity_path_index = input_json["identity_path_index"]
+        .as_array()
+        .unwrap()
+        .iter()
+        .map(|v| v.as_u64().unwrap() as u8)
+        .collect();
 
     let x = str_to_field(input_json["x"].to_string(), 10);
 
@@ -430,15 +434,17 @@ pub fn generate_proof(
 ) -> Result<Proof, ProofError> {
     // We confert the path indexes to field elements
     // TODO: check if necessary
-    let mut path_elements: Vec<BigInt> = Vec::new();
-    for v in rln_witness.path_elements.iter() {
-        path_elements.push(BigInt::from(*v));
-    }
+    let mut path_elements = Vec::new();
+    rln_witness
+        .path_elements
+        .iter()
+        .for_each(|v| path_elements.push(BigInt::from(*v)));
 
-    let mut identity_path_index: Vec<BigInt> = Vec::new();
-    for v in rln_witness.identity_path_index.iter() {
-        identity_path_index.push(BigInt::from(*v));
-    }
+    let mut identity_path_index = Vec::new();
+    rln_witness
+        .identity_path_index
+        .iter()
+        .for_each(|v| identity_path_index.push(BigInt::from(*v)));
 
     let inputs = [
         (

rln/src/utils.rs

@@ -28,36 +28,20 @@ pub fn to_field(el: &Fr) -> Field {
     (*el).try_into().unwrap()
 }
 
-pub fn vec_to_fr(v: &Vec<Field>) -> Vec<Fr> {
-    let mut result: Vec<Fr> = vec![];
-    for el in v {
-        result.push(to_fr(el));
-    }
-    result
+pub fn vec_to_fr(v: &[Field]) -> Vec<Fr> {
+    v.iter().map(|el| to_fr(el)).collect()
 }
 
-pub fn vec_to_field(v: &Vec<Fr>) -> Vec<Field> {
-    let mut result: Vec<Field> = vec![];
-    for el in v {
-        result.push(to_field(el));
-    }
-    result
+pub fn vec_to_field(v: &[Fr]) -> Vec<Field> {
+    v.iter().map(|el| to_field(el)).collect()
 }
 
-pub fn vec_fr_to_field(input: &Vec<Fr>) -> Vec<Field> {
-    let mut res: Vec<Field> = Vec::new();
-    for el in input {
-        res.push(to_field(el));
-    }
-    res
+pub fn vec_fr_to_field(input: &[Fr]) -> Vec<Field> {
+    input.iter().map(|el| to_field(el)).collect()
 }
 
-pub fn vec_field_to_fr(input: &Vec<Field>) -> Vec<Fr> {
-    let mut res: Vec<Fr> = Vec::new();
-    for el in input {
-        res.push(to_fr(el));
-    }
-    res
+pub fn vec_field_to_fr(input: &[Field]) -> Vec<Fr> {
+    input.iter().map(|el| to_fr(el)).collect()
 }
 
 pub fn str_to_field(input: String, radix: i32) -> Field {
@@ -136,37 +120,35 @@ pub fn field_to_bytes_be(input: &Field) -> Vec<u8> {
     fr_to_bytes_be(&to_fr(input))
 }
 
-pub fn vec_fr_to_bytes_le(input: &Vec<Fr>) -> Vec<u8> {
+pub fn vec_fr_to_bytes_le(input: &[Fr]) -> Vec<u8> {
     let mut bytes: Vec<u8> = Vec::new();
     //We store the vector length
     bytes.extend(input.len().to_le_bytes().to_vec());
     // We store each element
-    for el in input {
-        bytes.extend(fr_to_bytes_le(el));
-    }
+    input.iter().for_each(|el| bytes.extend(fr_to_bytes_le(el)));
+
     bytes
 }
 
-pub fn vec_fr_to_bytes_be(input: &Vec<Fr>) -> Vec<u8> {
+pub fn vec_fr_to_bytes_be(input: &[Fr]) -> Vec<u8> {
     let mut bytes: Vec<u8> = Vec::new();
     //We store the vector length
     bytes.extend(input.len().to_be_bytes().to_vec());
     // We store each element
-    for el in input {
-        bytes.extend(fr_to_bytes_be(el));
-    }
+    input.iter().for_each(|el| bytes.extend(fr_to_bytes_be(el)));
+
     bytes
 }
 
-pub fn vec_field_to_bytes_le(input: &Vec<Field>) -> Vec<u8> {
+pub fn vec_field_to_bytes_le(input: &[Field]) -> Vec<u8> {
     vec_fr_to_bytes_le(&vec_field_to_fr(input))
 }
 
-pub fn vec_field_to_bytes_be(input: &Vec<Field>) -> Vec<u8> {
+pub fn vec_field_to_bytes_be(input: &[Field]) -> Vec<u8> {
     vec_fr_to_bytes_be(&vec_field_to_fr(input))
 }
 
-pub fn vec_u8_to_bytes_le(input: &Vec<u8>) -> Vec<u8> {
+pub fn vec_u8_to_bytes_le(input: &[u8]) -> Vec<u8> {
     let mut bytes: Vec<u8> = Vec::new();
     //We store the vector length
     bytes.extend(u64::try_from(input.len()).unwrap().to_le_bytes().to_vec());