intervalstore: fix uint64 overflow

ethersphere · Apr 28, 2021 · 0eb06e9 · 0eb06e9
1 parent dda4d16
commit 0eb06e9
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Showing 2 changed files with 25 additions and 3 deletions.
diff --git a/pkg/intervalstore/intervals.go b/pkg/intervalstore/intervals.go
@@ -24,6 +24,7 @@ package intervalstore
 import (
 	"bytes"
 	"fmt"
+	"math"
 	"strconv"
 	"sync"
 )
@@ -68,19 +69,23 @@ func (i *Intervals) add(start, end uint64) {
 	if end < i.start {
 		return
 	}
+	endCheck := end + 1
+	if end == math.MaxUint64 {
+		endCheck = end
+	}
 	minStartJ := -1
 	maxEndJ := -1
 	j := 0
 	for ; j < len(i.ranges); j++ {
 		if minStartJ < 0 {
-			if (start <= i.ranges[j][0] && end+1 >= i.ranges[j][0]) || (start <= i.ranges[j][1]+1 && end+1 >= i.ranges[j][1]) {
+			if (start <= i.ranges[j][0] && endCheck >= i.ranges[j][0]) || (start <= i.ranges[j][1]+1 && endCheck >= i.ranges[j][1]) {
 				if i.ranges[j][0] < start {
 					start = i.ranges[j][0]
 				}
 				minStartJ = j
 			}
 		}
-		if (start <= i.ranges[j][1] && end+1 >= i.ranges[j][1]) || (start <= i.ranges[j][0] && end+1 >= i.ranges[j][0]) {
+		if (start <= i.ranges[j][1] && endCheck >= i.ranges[j][1]) || (start <= i.ranges[j][0] && endCheck >= i.ranges[j][0]) {
 			if i.ranges[j][1] > end {
 				end = i.ranges[j][1]
 			}

diff --git a/pkg/intervalstore/intervals_test.go b/pkg/intervalstore/intervals_test.go
@@ -16,7 +16,10 @@
 
 package intervalstore
 
-import "testing"
+import (
+	"math"
+	"testing"
+)
 
 // Test tests Interval methods Add, Next and Last for various
 // initial state.
@@ -471,3 +474,17 @@ func TestMerge(t *testing.T) {
 		}
 	}
 }
+
+// TestMaxUint64 is a regression test to verify that interval
+// is handled correctly at the edges.
+func TestMaxUint64(t *testing.T) {
+	intervals := NewIntervals(1)
+	intervals.Add(math.MaxUint64-1, math.MaxUint64)
+	intervals.Add(1, math.MaxUint64)
+	intervals.Add(2, math.MaxUint64)
+	intervals.Add(math.MaxUint64, math.MaxUint64)
+	wantstr := "[[1 18446744073709551615]]"
+	if s := intervals.String(); s != wantstr {
+		t.Fatalf("got interval string '%s' want '%s'", s, wantstr)
+	}
+}