From 6a73f61a915f28f0575a84369f64387249297d73 Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Wed, 19 Jul 2017 19:47:31 -0700
Subject: [PATCH] crypto: do not call out for merkle building.

---
 lib/crypto/merkle.js | 43 ++++++++++++++-----------------------------
 1 file changed, 14 insertions(+), 29 deletions(-)

diff --git a/lib/crypto/merkle.js b/lib/crypto/merkle.js
index 89e0fe2b..8e05dd73 100644
--- a/lib/crypto/merkle.js
+++ b/lib/crypto/merkle.js
@@ -12,7 +12,6 @@
  */
 
 const digest = require('./digest');
-const native = require('../native').binding;
 
 /**
  * Build a merkle tree from leaves.
@@ -27,20 +26,18 @@ exports.createTree = function createTree(leaves) {
   let malleated = false;
 
   if (size === 0) {
-    let hash = Buffer.allocUnsafe(32);
-    hash.fill(0);
-    nodes.push(hash);
+    nodes.push(Buffer.alloc(32));
     return [nodes, malleated];
   }
 
-  for (let j = 0; size > 1; size = (size + 1) >>> 1) {
-    for (let i = 0; i < size; i += 2) {
-      let k = Math.min(i + 1, size - 1);
-      let left = nodes[j + i];
-      let right = nodes[j + k];
+  for (let i = 0; size > 1; size = (size + 1) >>> 1) {
+    for (let j = 0; j < size; j += 2) {
+      let k = Math.min(j + 1, size - 1);
+      let left = nodes[i + j];
+      let right = nodes[i + k];
       let hash;
 
-      if (k === i + 1 && k + 1 === size
+      if (k === j + 1 && k + 1 === size
           && left.equals(right)) {
         malleated = true;
       }
@@ -49,15 +46,12 @@ exports.createTree = function createTree(leaves) {
 
       nodes.push(hash);
     }
-    j += size;
+    i += size;
   }
 
   return [nodes, malleated];
 };
 
-if (native)
-  exports.createTree = native.createMerkleTree;
-
 /**
  * Calculate merkle root from leaves.
  * @param {Buffer[]} leaves
@@ -79,15 +73,14 @@ exports.createRoot = function createRoot(leaves) {
 
 exports.createBranch = function createBranch(index, leaves) {
   let size = leaves.length;
-  let tree = exports.createTree(leaves);
+  let [nodes] = exports.createTree(leaves);
   let branch = [];
-  let j = 0;
 
-  for (; size > 1; size = (size + 1) >>> 1) {
-    let i = Math.min(index ^ 1, size - 1);
-    branch.push(tree.nodes[j + i]);
+  for (let i = 0; size > 1; size = (size + 1) >>> 1) {
+    let j = Math.min(index ^ 1, size - 1);
+    branch.push(nodes[i + j]);
     index >>>= 1;
-    j += size;
+    i += size;
   }
 
   return branch;
@@ -102,12 +95,7 @@ exports.createBranch = function createBranch(index, leaves) {
  */
 
 exports.verifyBranch = function verifyBranch(hash, branch, index) {
-  if (branch.length === 0)
-    return hash;
-
-  for (let i = 0; i < branch.length; i++) {
-    let otherside = branch[i];
-
+  for (let otherside of branch) {
     if (index & 1)
       hash = digest.root256(otherside, hash);
     else
@@ -118,6 +106,3 @@ exports.verifyBranch = function verifyBranch(hash, branch, index) {
 
   return hash;
 };
-
-if (native)
-  exports.verifyBranch = native.verifyMerkleBranch;