X-Git-Url: https://git.arvados.org/lightning.git/blobdiff_plain/dc0b5b0294a8ba771407c4c193b2e8017bf6315e..6e83d50c4d29656055a9c8e1a155309017a0d66d:/mask.go

diff --git a/mask.go b/mask.go
index bf7487948d..42232e04f5 100644
--- a/mask.go
+++ b/mask.go
@@ -1,3 +1,7 @@
+// Copyright (C) The Lightning Authors. All rights reserved.
+//
+// SPDX-License-Identifier: AGPL-3.0
+
 package lightning
 
 import (
@@ -23,6 +27,9 @@ type mask struct {
 }
 
 func (m *mask) Add(seqname string, start, end int) {
+	if m.frozen {
+		panic("bug: (*mask)Add() called after Freeze()")
+	}
 	if m.intervals == nil {
 		m.intervals = map[string][]interval{}
 	}
@@ -44,6 +51,17 @@ func (m *mask) Check(seqname string, start, end int) bool {
 	return m.itrees[seqname].check(0, interval{start, end})
 }
 
+func (m *mask) Len() int {
+	if !m.frozen {
+		return 0
+	}
+	n := 0
+	for _, intervals := range m.intervals {
+		n += len(intervals)
+	}
+	return n
+}
+
 func (m *mask) freeze(in []interval) intervalTree {
 	if len(in) == 0 {
 		return nil
@@ -56,10 +74,10 @@ func (m *mask) freeze(in []interval) intervalTree {
 		itreesize = itreesize * 2
 	}
 	itree := make(intervalTree, itreesize)
-	itree.importSlice(0, in)
-	for i := len(in); i < itreesize; i++ {
+	for i := 0; i < itreesize; i++ {
 		itree[i].maxend = -1
 	}
+	itree.importSlice(0, in)
 	return itree
 }