From 03211391a56ada98ca69260de1cb7606076b7dd2 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Thu, 11 Apr 2013 21:30:06 +0100
Subject: [PATCH] Fix: buffer.copy ignores sourceEnd if it's set to 0

---
 index.js       | 4 +++-
 test/buffer.js | 9 +++++++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/index.js b/index.js
index a4bf90c..19aae8f 100644
--- a/index.js
+++ b/index.js
@@ -306,7 +306,9 @@ Buffer.prototype.slice = function(start, end) {
 Buffer.prototype.copy = function(target, target_start, start, end) {
   var source = this;
   start || (start = 0);
-  end || (end = this.length);
+  if (end === undefined || isNaN(end)) {
+    end = this.length;
+  }
   target_start || (target_start = 0);
 
   if (end < start) throw new Error('sourceEnd < sourceStart');
diff --git a/test/buffer.js b/test/buffer.js
index 93b08b4..f431cc3 100644
--- a/test/buffer.js
+++ b/test/buffer.js
@@ -223,3 +223,12 @@ test("fill", function(t) {
     t.equal(b.toString('hex'), '02020202020202020202');
     t.end();
 });
+
+test('copy() empty buffer with sourceEnd=0', function (t) {
+    t.plan(1);
+    var source = new B([42]);
+    var destination = new B([43]);
+    source.copy(destination, 0, 0, 0);
+    t.equal(destination.readUInt8(0), 43);
+    t.end();
+});
-- 
2.34.1