feat: added MerkleStore serde

src/merkle/store/mod.rs

@@ -2,6 +2,7 @@ use super::{
     BTreeMap, BTreeSet, EmptySubtreeRoots, MerkleError, MerklePath, MerklePathSet, MerkleTree,
     NodeIndex, RootPath, Rpo256, RpoDigest, SimpleSmt, ValuePath, Vec, Word,
 };
+use crate::utils::{ByteReader, ByteWriter, Deserializable, DeserializationError, Serializable};
 
 #[cfg(test)]
 mod tests;
@@ -430,3 +431,47 @@ impl MerkleStore {
         }
     }
 }
+
+// SERIALIZATION
+// ================================================================================================
+
+impl Serializable for Node {
+    fn write_into<W: ByteWriter>(&self, target: &mut W) {
+        self.left.write_into(target);
+        self.right.write_into(target);
+    }
+}
+
+impl Deserializable for Node {
+    fn read_from<R: ByteReader>(source: &mut R) -> Result<Self, DeserializationError> {
+        let left = RpoDigest::read_from(source)?;
+        let right = RpoDigest::read_from(source)?;
+        Ok(Node { left, right })
+    }
+}
+
+impl Serializable for MerkleStore {
+    fn write_into<W: ByteWriter>(&self, target: &mut W) {
+        target.write_u64(self.nodes.len() as u64);
+
+        for (k, v) in self.nodes.iter() {
+            k.write_into(target);
+            v.write_into(target);
+        }
+    }
+}
+
+impl Deserializable for MerkleStore {
+    fn read_from<R: ByteReader>(source: &mut R) -> Result<Self, DeserializationError> {
+        let len = source.read_u64()?;
+        let mut nodes: BTreeMap<RpoDigest, Node> = BTreeMap::new();
+
+        for _ in 0..len {
+            let key = RpoDigest::read_from(source)?;
+            let value = Node::read_from(source)?;
+            nodes.insert(key, value);
+        }
+
+        Ok(MerkleStore { nodes })
+    }
+}

src/merkle/store/tests.rs

@@ -5,6 +5,9 @@ use crate::{
     Felt, Word,
 };
 
+#[cfg(std)]
+use std::error::Error;
+
 const KEYS4: [u64; 4] = [0, 1, 2, 3];
 const LEAVES4: [Word; 4] = [
     int_to_node(1),
@@ -554,3 +557,12 @@ fn test_constructors() -> Result<(), MerkleError> {
 
     Ok(())
 }
+
+#[cfg(std)]
+#[test]
+fn test_serialization() -> Result<(), Box<dyn Error>> {
+    let original = MerkleStore::new().with_merkle_tree(LEAVES4)?;
+    let decoded = MerkleStore::read_from_bytes(&original.to_bytes())?;
+    assert_eq!(original, decoded);
+    Ok(())
+}