From 1b868b6a9dbd2c42ff05153e3c89553121249482 Mon Sep 17 00:00:00 2001
From: Matthew Zipkin <pinheadmz@gmail.com>
Date: Tue, 2 Apr 2019 16:49:35 -0700
Subject: [PATCH 1/2] util: reverse buffers instead of strings

---
 lib/utils/util.js | 18 +++---------------
 1 file changed, 3 insertions(+), 15 deletions(-)

diff --git a/lib/utils/util.js b/lib/utils/util.js
index 7e3b4a28..0ab6d5c4 100644
--- a/lib/utils/util.js
+++ b/lib/utils/util.js
@@ -96,31 +96,19 @@ util.time = function time(date) {
 
 /**
  * Reverse a hex-string.
- * @param {String} str - Hex string.
+ * @param {Buffer}
  * @returns {String} Reversed hex string.
  */
 
 util.revHex = function revHex(buf) {
   assert(Buffer.isBuffer(buf));
 
-  const str = buf.toString('hex');
-
-  let out = '';
-
-  for (let i = str.length - 2; i >= 0; i -= 2)
-    out += str[i] + str[i + 1];
-
-  return out;
+  return Buffer.from(buf).reverse().toString('hex');
 };
 
 util.fromRev = function fromRev(str) {
   assert(typeof str === 'string');
   assert((str.length & 1) === 0);
 
-  let out = '';
-
-  for (let i = str.length - 2; i >= 0; i -= 2)
-    out += str[i] + str[i + 1];
-
-  return Buffer.from(out, 'hex');
+  return Buffer.from(str, 'hex').reverse();
 };

From fc7fd3cb4bd4481b2bfcbc7bb6f902fbdcd98393 Mon Sep 17 00:00:00 2001
From: Matthew Zipkin <pinheadmz@gmail.com>
Date: Thu, 4 Apr 2019 23:59:30 -0700
Subject: [PATCH 2/2] bench: reverse hex string hash

---
 bench/hexstring.js | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)
 create mode 100644 bench/hexstring.js

diff --git a/bench/hexstring.js b/bench/hexstring.js
new file mode 100644
index 00000000..c57e1319
--- /dev/null
+++ b/bench/hexstring.js
@@ -0,0 +1,17 @@
+'use strict';
+
+const random = require('bcrypto/lib/random');
+const util = require('../lib/utils/util');
+const bench = require('./bench');
+
+const hashes = [];
+
+for (let i = 0; i < 100000; i++)
+  hashes.push(random.randomBytes(32));
+
+{
+  const end = bench('hexstring');
+  for (let i = 0; i < hashes.length; i++)
+    util.fromRev(util.revHex(hashes[i]));
+  end(100000);
+}