bufferutils: add Buffer reverse

src/bufferutils.js

@@ -159,11 +159,18 @@ function writeVarInt(buffer, number, offset) {
   return size
 }
 
+function reverse(buffer) {
+  var buffer2 = new Buffer(buffer)
+  Array.prototype.reverse.call(buffer2)
+  return buffer2
+}
+
 module.exports = {
   pushDataSize: pushDataSize,
   readPushDataInt: readPushDataInt,
   readUInt64LE: readUInt64LE,
   readVarInt: readVarInt,
+  reverse: reverse,
   varIntSize: varIntSize,
   writePushDataInt: writePushDataInt,
   writeUInt64LE: writeUInt64LE,

src/transaction.js

@@ -37,10 +37,8 @@ Transaction.prototype.addInput = function(tx, index, sequence) {
   var hash
 
   if (typeof tx === 'string') {
-    hash = new Buffer(tx, 'hex')
-
     // TxId hex is big-endian, we need little-endian
-    Array.prototype.reverse.call(hash)
+    hash = bufferutils.reverse(new Buffer(tx, 'hex'))
 
   } else if (tx instanceof Transaction) {
     hash = tx.getHash()
@@ -211,12 +209,8 @@ Transaction.prototype.getHash = function () {
 }
 
 Transaction.prototype.getId = function () {
-  var buffer = this.getHash()
-
-  // Big-endian is used for TxHash
-  Array.prototype.reverse.call(buffer)
-
-  return buffer.toString('hex')
+  // TxHash is little-endian, we need big-endian
+  return bufferutils.reverse(this.getHash()).toString('hex')
 }
 
 Transaction.prototype.clone = function () {

src/wallet.js

@@ -1,4 +1,5 @@
 var assert = require('assert')
+var bufferutils = require('./bufferutils')
 var crypto = require('crypto')
 var networks = require('./networks')
 
@@ -123,10 +124,7 @@ Wallet.prototype.__processTx = function(tx, isPending) {
 
   tx.ins.forEach(function(txIn, i) {
     // copy and convert to big-endian hex
-    var txinId = new Buffer(txIn.hash)
-    Array.prototype.reverse.call(txinId)
-    txinId = txinId.toString('hex')
-
+    var txinId = bufferutils.reverse(txIn.hash).toString('hex')
     var output = txinId + ':' + txIn.index
 
     if (!(output in this.outputs)) return

test/bufferutils.js

@@ -75,6 +75,19 @@ describe('bufferutils', function() {
     })
   })
 
+  describe('reverse', function() {
+    fixtures.valid.forEach(function(f) {
+      it('reverses ' + f.hex64 + ' correctly', function() {
+        var buffer = new Buffer(f.hex64, 'hex')
+        var buffer2 = bufferutils.reverse(buffer)
+
+        Array.prototype.reverse.call(buffer)
+
+        assert.deepEqual(buffer, buffer2)
+      })
+    })
+  })
+
   describe('varIntSize', function() {
     fixtures.valid.forEach(function(f) {
       it('determines the varIntSize of ' + f.dec + ' correctly', function() {