From 78d3aa2dbc2d7f5cde8be9adcaca7e41f9e50bf5 Mon Sep 17 00:00:00 2001
From: Maxim Babichev <maksim.babichev95@gmail.com>
Date: Thu, 10 Aug 2023 18:42:56 +0300
Subject: [PATCH] bugfix

---
 packer.go      |  5 +++--
 packer_test.go | 26 ++++++++++++++++++++++++++
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/packer.go b/packer.go
index 8136249..2771d34 100644
--- a/packer.go
+++ b/packer.go
@@ -72,10 +72,11 @@ func (p *Packer) preferredSort(boxes boxSlice, items itemSlice) boxSlice {
 func (p *Packer) packToBox(b *Box, items []*Item) []*Item {
 	var fitted bool
 
-	unpacked := make([]*Item, 0, len(items))
+	cntItems := len(items)
+	unpacked := make([]*Item, 0, cntItems)
 	pv := Pivot{}
 
-	if b.items == nil && b.PutItem(items[0], pv) {
+	if b.items == nil && cntItems > 0 && b.PutItem(items[0], pv) {
 		items = items[1:]
 	}
 
diff --git a/packer_test.go b/packer_test.go
index eac813b..916a656 100644
--- a/packer_test.go
+++ b/packer_test.go
@@ -79,6 +79,32 @@ func TestBoxPackerSuite(t *testing.T) {
 	suite.Run(t, new(PackerSuit))
 }
 
+func (s *PackerSuit) TestEmptyBoxes() {
+	t := s.T()
+	t.Parallel()
+
+	packer := boxpacker3.NewPacker()
+
+	packResult := packer.Pack(nil, nil)
+	require.NotNil(t, packResult)
+	require.Len(t, packResult.Boxes, 0)
+	require.Len(t, packResult.UnfitItems, 0)
+}
+
+func (s *PackerSuit) TestEmptyItems() {
+	t := s.T()
+	t.Parallel()
+
+	packer := boxpacker3.NewPacker()
+
+	boxes := NewDefaultBoxList()
+
+	packResult := packer.Pack(boxes, nil)
+	require.NotNil(t, packResult)
+	require.Len(t, packResult.Boxes, len(boxes))
+	require.Len(t, packResult.UnfitItems, 0)
+}
+
 func (s *PackerSuit) TestMinBox() {
 	t := s.T()
 	t.Parallel()