From 2214ccfdd80205276c96fd569f98aa37c0d6692d Mon Sep 17 00:00:00 2001
From: Daniel Cousens <github@dcousens.com>
Date: Fri, 17 Oct 2014 13:07:14 +1100
Subject: [PATCH] bufferutils: add varIntBuffer

---
 src/block.js        |  8 +-------
 src/bufferutils.js  |  9 +++++++++
 src/message.js      |  3 +--
 test/bufferutils.js | 12 +++++++++++-
 4 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/src/block.js b/src/block.js
index f25e1c5..8fcce5a 100644
--- a/src/block.js
+++ b/src/block.js
@@ -120,13 +120,7 @@ Block.prototype.toBuffer = function(headersOnly) {
 
   if (headersOnly || !this.transactions) return buffer
 
-  function varIntBuffer(i) {
-    var ib = new Buffer(bufferutils.varIntSize(i))
-    bufferutils.writeVarInt(ib, i, 0)
-    return ib
-  }
-
-  var txLenBuffer = varIntBuffer(this.transactions.length)
+  var txLenBuffer = bufferutils.varIntBuffer(this.transactions.length)
   var txBuffers = this.transactions.map(function(tx) {
     return tx.toBuffer()
   })
diff --git a/src/bufferutils.js b/src/bufferutils.js
index 858a934..644db88 100644
--- a/src/bufferutils.js
+++ b/src/bufferutils.js
@@ -159,6 +159,14 @@ function writeVarInt(buffer, number, offset) {
   return size
 }
 
+function varIntBuffer(i) {
+  var size = varIntSize(i)
+  var buffer = new Buffer(size)
+  writeVarInt(buffer, i, 0)
+
+  return buffer
+}
+
 function reverse(buffer) {
   var buffer2 = new Buffer(buffer)
   Array.prototype.reverse.call(buffer2)
@@ -171,6 +179,7 @@ module.exports = {
   readUInt64LE: readUInt64LE,
   readVarInt: readVarInt,
   reverse: reverse,
+  varIntBuffer: varIntBuffer,
   varIntSize: varIntSize,
   writePushDataInt: writePushDataInt,
   writeUInt64LE: writeUInt64LE,
diff --git a/src/message.js b/src/message.js
index 76ba3f0..6305a69 100644
--- a/src/message.js
+++ b/src/message.js
@@ -13,8 +13,7 @@ var ecparams = ecurve.getCurveByName('secp256k1')
 function magicHash(message, network) {
   var magicPrefix = new Buffer(network.magicPrefix)
   var messageBuffer = new Buffer(message)
-  var lengthBuffer = new Buffer(bufferutils.varIntSize(messageBuffer.length))
-  bufferutils.writeVarInt(lengthBuffer, messageBuffer.length, 0)
+  var lengthBuffer = bufferutils.varIntBuffer(messageBuffer.length)
 
   var buffer = Buffer.concat([magicPrefix, lengthBuffer, messageBuffer])
   return crypto.hash256(buffer)
diff --git a/test/bufferutils.js b/test/bufferutils.js
index 447d516..8fc054c 100644
--- a/test/bufferutils.js
+++ b/test/bufferutils.js
@@ -88,6 +88,16 @@ describe('bufferutils', function() {
     })
   })
 
+  describe('varIntBuffer', function() {
+    fixtures.valid.forEach(function(f) {
+      it('encodes ' + f.dec + ' correctly', function() {
+        var buffer = bufferutils.varIntBuffer(f.dec)
+
+        assert.equal(buffer.toString('hex'), f.hexVI)
+      })
+    })
+  })
+
   describe('varIntSize', function() {
     fixtures.valid.forEach(function(f) {
       it('determines the varIntSize of ' + f.dec + ' correctly', function() {
@@ -99,7 +109,7 @@ describe('bufferutils', function() {
   })
 
   describe('writePushDataInt', function() {
-    fixtures.valid.forEach(function(f, i) {
+    fixtures.valid.forEach(function(f) {
       if (!f.hexPD) return
 
       it('encodes ' + f.dec + ' correctly', function() {