add Len() and ContainsPacketNumber() to NackRange

frames/nack_range.go

@@ -0,0 +1,22 @@
+package frames
+
+import "github.com/lucas-clemente/quic-go/protocol"
+
+// NackRange is a NACK range
+type NackRange struct {
+	FirstPacketNumber protocol.PacketNumber
+	LastPacketNumber  protocol.PacketNumber
+}
+
+// Len gets the lengths of a NackRange
+func (n *NackRange) Len() uint64 {
+	return uint64(n.LastPacketNumber) - uint64(n.FirstPacketNumber)
+}
+
+// IsInRange checks if a packetNumber is contained in a NACK range
+func (n *NackRange) ContainsPacketNumber(packetNumber protocol.PacketNumber) bool {
+	if packetNumber >= n.FirstPacketNumber && packetNumber <= n.LastPacketNumber {
+		return true
+	}
+	return false
+}