Change signatures of share validation fns

* Pass a ref to `Vec<Shares>` instead of recreating and moving the object
  through several functions.
* Return `slen`/ `data_len`, since we'll be using it anyway in `recover_secrets`

src/dss/ss1/scheme.rs

@@ -247,7 +247,8 @@ impl SS1 {
         &self,
         shares: &[Share],
     ) -> Result<(Vec<u8>, AccessStructure, Option<MetaData>)> {
-        let (_, shares) = validate_shares(shares.to_vec())?;
+        let shares = shares.to_vec();
+        validate_shares(&shares)?;
 
         let underlying_shares = shares
             .iter()

src/dss/thss/scheme.rs

@@ -89,9 +89,8 @@ impl ThSS {
         &self,
         shares: &[Share],
     ) -> Result<(Vec<u8>, AccessStructure, Option<MetaData>)> {
-        let (threshold, shares) = validate_shares(shares.to_vec())?;
-
-        let cypher_len = shares[0].data.len();
+        let shares = shares.to_vec();
+        let (threshold, cypher_len) = validate_shares(&shares)?;
 
         let polys = (0..cypher_len)
             .map(|i| {

src/share/validation.rs

@@ -11,27 +11,27 @@ use share::{IsShare, IsSignedShare};
 
 /// TODO: Doc
 pub(crate) fn validate_signed_shares<S: IsSignedShare>(
-    shares: Vec<S>,
+    shares: &Vec<S>,
     verify_signatures: bool,
-) -> Result<(u8, Vec<S>)> {
-    let (threshold, shares) = validate_shares(shares)?;
+) -> Result<(u8, usize)> {
+    let result = validate_shares(shares)?;
 
     if verify_signatures {
         S::verify_signatures(&shares)?;
     }
 
-    Ok((threshold, shares))
+    Ok(result)
 }
 
 /// TODO: Doc
-pub(crate) fn validate_shares<S: IsShare>(shares: Vec<S>) -> Result<(u8, Vec<S>)> {
+pub(crate) fn validate_shares<S: IsShare>(shares: &Vec<S>) -> Result<(u8, usize)> {
     if shares.is_empty() {
         bail!(ErrorKind::EmptyShares);
     }
 
     let shares_count = shares.len();
-    let mut result: Vec<S> = Vec::with_capacity(shares_count);
 
+    let mut ids = Vec::with_capacity(shares_count);
     let mut k_compatibility_sets = HashMap::new();
     let mut data_len_compatibility_sets = HashMap::new();
 
@@ -52,7 +52,7 @@ pub(crate) fn validate_shares<S: IsShare>(shares: Vec<S>) -> Result<(u8, Vec<S>)
         let k_set = k_compatibility_sets.get_mut(&threshold).unwrap();
         k_set.insert(id);
 
-        if result.iter().any(|s| s.get_id() == id) {
+        if ids.iter().any(|&x| x == id) {
             bail!(ErrorKind::DuplicateShareId(id));
         }
 
@@ -62,8 +62,7 @@ pub(crate) fn validate_shares<S: IsShare>(shares: Vec<S>) -> Result<(u8, Vec<S>)
         let data_len_set = data_len_compatibility_sets.get_mut(&data_len).unwrap();
         data_len_set.insert(id);
 
-
-        result.push(share);
+        ids.push(id);
     }
 
     // Validate threshold
@@ -107,7 +106,10 @@ pub(crate) fn validate_shares<S: IsShare>(shares: Vec<S>) -> Result<(u8, Vec<S>)
         }
     }
 
-    Ok((threshold, result))
+    // It is safe to unwrap because data_len_sets == 1
+    let slen = data_len_compatibility_sets.keys().last().unwrap().to_owned();
+
+    Ok((threshold, data_len))
 }
 
 pub(crate) fn validate_share_count(threshold: u8, shares_count: u8) -> Result<(u8, u8)> {

src/sss/scheme.rs

@@ -93,9 +93,8 @@ impl SSS {
     ///
     /// At least `k` distinct shares need to be provided to recover the share.
     pub fn recover_secret(shares: Vec<Share>, verify_signatures: bool) -> Result<Vec<u8>> {
-        let (threshold, shares) = validate_signed_shares(shares, verify_signatures)?;
+        let (threshold, slen) = validate_signed_shares(&shares, verify_signatures)?;
 
-        let slen = shares[0].data.len();
         let mut col_in = Vec::with_capacity(threshold as usize);
         let mut secret = Vec::with_capacity(slen);
         for byteindex in 0..slen {