enhancement/merkle

Sources/BeaconChain/BeaconChain.swift

@@ -200,17 +200,6 @@ extension BeaconChain {
         return firstCommittee[Int(slot) % firstCommittee.count]
     }
 
-    static func merkleRoot(values: [Bytes32]) -> Bytes32 {
-        var o = [Data](repeating: Data(repeating: 0, count: 1), count: values.count - 1)
-        o.append(contentsOf: values)
-
-        for i in stride(from: values.count - 1, through: 0, by: -1) {
-            o[i] = hash(o[i * 2] + o[i * 2 + 1])
-        }
-
-        return o[1]
-    }
-
     static func getAttestationParticipants(
         state: BeaconState,
         attestationData: AttestationData,

Sources/BeaconChain/Merkle.swift

@@ -0,0 +1,28 @@
+import Foundation
+
+class Merkle {
+
+    static func root(_ values: [Bytes32]) -> Bytes32 {
+        var o = [Data](repeating: Data(repeating: 0, count: 1), count: values.count - 1)
+        o.append(contentsOf: values)
+
+        for i in stride(from: values.count - 1, through: 0, by: -1) {
+            o[i] = BeaconChain.hash(o[i * 2] + o[i * 2 + 1])
+        }
+
+        return o[1]
+    }
+
+    static func verifyBranch(leaf: Bytes32, branch: [Bytes32], depth: Int, index: Int, root: Bytes32) -> Bool {
+        var value = leaf
+        for i in 0..<depth {
+            if index / (2 ** i) % 2 == 1 {
+                value = BeaconChain.hash(branch[i] + value)
+            } else {
+                value = BeaconChain.hash(value + branch[i])
+            }
+        }
+
+        return value == root
+    }
+}

Sources/BeaconChain/StateTransition.swift

@@ -9,7 +9,7 @@ class StateTransition {
         state.latestBlockRoots[Int((state.slot - 1) % LATEST_BLOCK_ROOTS_LENGTH)] = previousBlockRoot
 
         if state.slot % LATEST_BLOCK_ROOTS_LENGTH == 0 {
-            state.batchedBlockRoots.append(BeaconChain.merkleRoot(values: state.latestBlockRoots))
+            state.batchedBlockRoots.append(Merkle.root(state.latestBlockRoots))
         }
     }
 }
@@ -224,7 +224,7 @@ extension StateTransition {
             let serializedDepositData = Data(count: 64) // @todo when we have SSZ
 
             assert(
-                verifyMerkleBranch(
+                Merkle.verifyBranch(
                     leaf: BeaconChain.hash(serializedDepositData),
                     branch: deposit.branch,
                     depth: Int(DEPOSIT_CONTRACT_TREE_DEPTH),
@@ -297,19 +297,6 @@ extension StateTransition {
             state.validatorBalances[Int(BeaconChain.getBeaconProposerIndex(state: state, slot: state.slot))] += transfer.fee
         }
     }
-
-    static func verifyMerkleBranch(leaf: Bytes32, branch: [Bytes32], depth: Int, index: Int, root: Bytes32) -> Bool {
-        var value = leaf
-        for i in 0..<depth {
-            if index / (2 ** i) % 2 == 1 {
-                value = BeaconChain.hash(branch[i] + value)
-            } else {
-                value = BeaconChain.hash(value + branch[i])
-            }
-        }
-
-        return value == root
-    }
 }
 
 extension StateTransition {