From feceaf429e16bb7cfa2889b720c066c88cd4d965 Mon Sep 17 00:00:00 2001
From: Ben Johnson <benbjohnson@yahoo.com>
Date: Wed, 26 Oct 2016 13:47:37 -0600
Subject: [PATCH] Avoid array write if length is zero.

---
 roaring/roaring.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/roaring/roaring.go b/roaring/roaring.go
index 6c65cc3ed..e3be2638f 100644
--- a/roaring/roaring.go
+++ b/roaring/roaring.go
@@ -1006,6 +1006,10 @@ func (c *container) WriteTo(w io.Writer) (n int64, err error) {
 }
 
 func (c *container) arrayWriteTo(w io.Writer) (n int64, err error) {
+	if len(c.array) == 0 {
+		return 0, nil
+	}
+
 	nn, err := w.Write((*[0xFFFFFFF]byte)(unsafe.Pointer(&c.array[0]))[:4*c.n])
 	return int64(nn), err
 }