chore: add template for the project

src/lib.rs

@@ -1,14 +1,62 @@
-pub fn add(left: usize, right: usize) -> usize {
-    left + right
-}
+pub struct Error(String);
+pub type Result<T> = std::result::Result<T, Error>;
 
-#[cfg(test)]
-mod tests {
-    use super::*;
+pub struct VecDB;
+pub struct Poseidon;
 
-    #[test]
-    fn it_works() {
-        let result = add(2, 2);
-        assert_eq!(result, 4);
+pub type DefaultDatabase = VecDB;
+pub type DefaultHasher = Poseidon;
+
+impl Hasher for Poseidon {
+    type Fr = i32;
+
+    fn hash(_input: &[i32]) -> i32 {
+        0
     }
 }
+
+impl Database for VecDB {
+    fn new(dbpath: &str) -> Self {
+        Self {}
+    }
+    fn get(&self, key: &[u8]) -> Result<Option<Vec<u8>>> {
+        Ok(Some(vec![]))
+    }
+    fn put(&mut self, key: &[u8]) -> Result<()> {
+        Ok(())
+    }
+    fn delete(&mut self, key: &[u8]) -> Result<()> {
+        Ok(())
+    }
+}
+
+pub trait Hasher {
+    type Fr: Copy + Eq + Default;
+
+    fn hash(input: &[Self::Fr]) -> Self::Fr;
+}
+
+pub trait Database {
+    fn new(dbpath: &str) -> Self;
+    fn get(&self, key: &[u8]) -> Result<Option<Vec<u8>>>;
+    fn put(&mut self, key: &[u8]) -> Result<()>;
+    fn delete(&mut self, key: &[u8]) -> Result<()>;
+}
+
+pub struct MerkleTree<D = DefaultDatabase, H = DefaultHasher>
+where
+    D: Database,
+    H: Hasher,
+{
+    db: D,
+    h: H,
+}
+
+impl MerkleTree {}
+
+impl<D, H> MerkleTree<D, H>
+where
+    D: Database,
+    H: Hasher,
+{
+}