Change state_hash to be a struct

src/utils/mod.rs

@@ -2,5 +2,8 @@ extern crate ethereum_types;
 extern crate blake2;
 extern crate crypto_mac;
 
+use super::state::active_state;
+use super::state::crystallized_state;
+
 pub mod types;
 pub mod bls;

src/utils/types.rs

@@ -1,4 +1,6 @@
 use super::ethereum_types::{ H256, H160 };
+use super::active_state::ActiveState;
+use super::crystallized_state::CrystallizedState;
 
 pub use super::blake2::Blake2s;
 
@@ -10,6 +12,25 @@ pub type Blake2sDigest = H256;
 
 pub type Address = H160;
 
-pub type StateHash = [u8; 64];
+pub struct StateHash {
+    pub active_state: Blake2sDigest,
+    pub crystallized_state: Blake2sDigest
+}
+
+impl StateHash {
+    pub fn zero() -> Self {
+        Self {
+            active_state: Blake2sDigest::zero(),
+            crystallized_state: Blake2sDigest::zero()
+        }
+    }
+
+    pub fn from_states(active: &ActiveState, crystal: &CrystallizedState) -> Self {
+        Self {
+            active_state: active.blake2s_hash(),
+            crystallized_state: crystal.blake2s_hash()
+        }
+    }
+}
 
 pub type Bitfield = Vec<u8>;