From 9b92a9d5fbd9333bb1e3c79ba6ba6f6b479fe930 Mon Sep 17 00:00:00 2001
From: Sean Bowe <ewillbefull@gmail.com>
Date: Thu, 21 Apr 2016 12:02:43 -0600
Subject: [PATCH] Make appending algorithm more succinct.

---
 src/zcash/IncrementalMerkleTree.cpp | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/src/zcash/IncrementalMerkleTree.cpp b/src/zcash/IncrementalMerkleTree.cpp
index 0a391486a..c47862d1f 100644
--- a/src/zcash/IncrementalMerkleTree.cpp
+++ b/src/zcash/IncrementalMerkleTree.cpp
@@ -93,22 +93,20 @@ void IncrementalMerkleTree<Depth, Hash>::append(Hash obj) {
         left = obj;
         right = boost::none;
 
-        // Propagate up the tree as much as needed
-        BOOST_FOREACH(boost::optional<Hash>& parent, parents) {
-            if (parent) {
-                combined = Hash::combine(*parent, *combined);
-                parent = boost::none;
+        for (size_t i = 0; i < Depth; i++) {
+            if (i < parents.size()) {
+                if (parents[i]) {
+                    combined = Hash::combine(*parents[i], *combined);
+                    parents[i] = boost::none;
+                } else {
+                    parents[i] = *combined;
+                    break;
+                }
             } else {
-                parent = *combined;
-                combined = boost::none;
+                parents.push_back(combined);
                 break;
             }
         }
-
-        if (combined) {
-            // Create a new parent
-            parents.push_back(combined);
-        }
     }
 }