From ac4010bce0951c60ffe1f648d830a9dfa0d0a6b9 Mon Sep 17 00:00:00 2001
From: Travis Turner <travis@pilosa.com>
Date: Fri, 9 Feb 2018 11:35:13 -0600
Subject: [PATCH] avoid overflow bug in differenceRunArray which was appending
 a full run to the container

---
 roaring/roaring.go               |  8 ++++++++
 roaring/roaring_internal_test.go | 10 ++++++++++
 2 files changed, 18 insertions(+)

diff --git a/roaring/roaring.go b/roaring/roaring.go
index a685e479c..efdce69a0 100644
--- a/roaring/roaring.go
+++ b/roaring/roaring.go
@@ -2504,6 +2504,8 @@ func differenceRunArray(a, b *container) *container {
 
 	bidx := 0
 	vb := b.array[bidx]
+
+RUNLOOP:
 	for _, run := range a.runs {
 		start := run.start
 		for vb < run.start {
@@ -2515,6 +2517,9 @@ func differenceRunArray(a, b *container) *container {
 		}
 		for vb >= run.start && vb <= run.last {
 			if vb == start {
+				if vb == 65535 { // overflow
+					break RUNLOOP
+				}
 				start++
 				bidx++
 				if bidx >= len(b.array) {
@@ -2525,6 +2530,9 @@ func differenceRunArray(a, b *container) *container {
 			}
 			output.runs = append(output.runs, interval16{start: start, last: vb - 1})
 			output.n += int(vb - start)
+			if vb == 65535 { // overflow
+				break RUNLOOP
+			}
 			start = vb + 1
 			bidx++
 			if bidx >= len(b.array) {
diff --git a/roaring/roaring_internal_test.go b/roaring/roaring_internal_test.go
index a2fbb7d64..f79f53053 100644
--- a/roaring/roaring_internal_test.go
+++ b/roaring/roaring_internal_test.go
@@ -1479,6 +1479,16 @@ func TestDifferenceRunArray(t *testing.T) {
 			array: []uint16{0, 9, 10, 11, 12, 13, 14, 17, 19, 25, 27},
 			exp:   []interval16{{start: 1, last: 8}, {start: 15, last: 16}, {start: 20, last: 24}, {start: 26, last: 26}, {start: 28, last: 28}},
 		},
+		{
+			runs:  []interval16{{start: 0, last: 20}, {start: 65533, last: 65535}},
+			array: []uint16{65533, 65534, 65535},
+			exp:   []interval16{{start: 0, last: 20}},
+		},
+		{
+			runs:  []interval16{{start: 0, last: 20}, {start: 65530, last: 65535}},
+			array: []uint16{37, 65535},
+			exp:   []interval16{{start: 0, last: 20}, {start: 65530, last: 65534}},
+		},
 	}
 	for i, test := range tests {
 		a.runs = test.runs