From 8daddcc458ad736993f8eb28f82149f30092c7e2 Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Tue, 13 Sep 2016 20:06:53 -0700
Subject: [PATCH] mnemonic: use a binary search for word indexes.

---
 lib/crypto/crypto.js |  5 +++--
 lib/hd/mnemonic.js   |  2 +-
 lib/utils/utils.js   | 27 +++++++++++++++++++--------
 3 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/lib/crypto/crypto.js b/lib/crypto/crypto.js
index 083c0655..d4bee3aa 100644
--- a/lib/crypto/crypto.js
+++ b/lib/crypto/crypto.js
@@ -11,6 +11,7 @@ var assert = require('assert');
 var random = require('./random');
 var scrypt = require('./scrypt');
 var scryptAsync = require('./scrypt-async');
+var utils = require('../utils/utils');
 var native = require('../utils/native');
 var nativeCrypto, supersha, hash, aes;
 
@@ -226,7 +227,7 @@ crypto.scrypt = function _scrypt(passwd, salt, N, r, p, len) {
  * @param {Function} callback
  */
 
-crypto.scryptAsync = function _scryptAsync(passwd, salt, N, r, p, len, callback) {
+crypto.scryptAsync = function _scrypt(passwd, salt, N, r, p, len, callback) {
   if (typeof passwd === 'string')
     passwd = new Buffer(passwd, 'utf8');
 
@@ -504,7 +505,7 @@ crypto.buildMerkleTree = function buildMerkleTree(leaves) {
       right = tree[j + i2];
 
       if (i2 === i + 1 && i2 + 1 === size
-          && left.compare(right) === 0) {
+          && utils.cmp(left, right) === 0) {
         return;
       }
 
diff --git a/lib/hd/mnemonic.js b/lib/hd/mnemonic.js
index 7b8dc365..0922d766 100644
--- a/lib/hd/mnemonic.js
+++ b/lib/hd/mnemonic.js
@@ -261,7 +261,7 @@ Mnemonic.prototype.fromPhrase = function fromPhrase(phrase) {
 
   for (i = 0; i < words.length; i++) {
     word = words[i];
-    index = wordlist.indexOf(word);
+    index = utils.binarySearch(wordlist, word, utils.strcmp);
 
     if (index === -1)
       throw new Error('Could not find word.');
diff --git a/lib/utils/utils.js b/lib/utils/utils.js
index 915a40fc..474ad6dd 100644
--- a/lib/utils/utils.js
+++ b/lib/utils/utils.js
@@ -1567,19 +1567,15 @@ utils.isZero = function isZero(data) {
 };
 
 /**
- * Buffer comparator (memcmp + length comparison).
+ * String comparator (memcmp + length comparison).
  * @param {Buffer} a
  * @param {Buffer} b
  * @returns {Number} -1, 1, or 0.
  */
 
-utils.cmp = function cmp(a, b) {
-  var len, i;
-
-  if (a.compare)
-    return a.compare(b);
-
-  len = Math.min(a.length, b.length);
+utils.strcmp = function strcmp(a, b) {
+  var len = Math.min(a.length, b.length);
+  var i;
 
   for (i = 0; i < len; i++) {
     if (a[i] < b[i])
@@ -1597,6 +1593,21 @@ utils.cmp = function cmp(a, b) {
   return 0;
 };
 
+/**
+ * Buffer comparator (memcmp + length comparison).
+ * @param {Buffer} a
+ * @param {Buffer} b
+ * @returns {Number} -1, 1, or 0.
+ */
+
+utils.cmp = function cmp(a, b) {
+  return a.compare(b);
+};
+
+// Warning: polymorphism.
+if (!Buffer.prototype.compare)
+  utils.cmp = utils.strcmp;
+
 /**
  * Memcmp for comparing a needle to a haystack.
  * @param {Buffer} target - Haystack.