From 94352b37314288b7fe23d44fc14835fcfc70fe33 Mon Sep 17 00:00:00 2001
From: defia <defiaq@gmail.com>
Date: Mon, 13 Jun 2016 11:16:19 +0800
Subject: [PATCH] fix issue 461  https://github.com/cyfdecyf/cow/issues/461

---
 util.go | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/util.go b/util.go
index 03ae87a6..0907dc0f 100644
--- a/util.go
+++ b/util.go
@@ -259,16 +259,13 @@ func copyN(dst io.Writer, src *bufio.Reader, n, rdSize int) (err error) {
 		}
 		nr := len(b)
 		n -= nr
-		if nr > 0 {
+		for nr > 0 {
 			nw, ew := dst.Write(b)
 			if ew != nil {
 				err = ew
 				break
 			}
-			if nr != nw {
-				err = io.ErrShortWrite
-				break
-			}
+			nr -= nw
 		}
 		if er == io.EOF {
 			break