From 96e843ceeed10c85317cb053f31b4986bd28e98c Mon Sep 17 00:00:00 2001
From: Jan-Simon Winkelmann <jwinkelmann@rapidsoft.de>
Date: Mon, 21 Sep 2020 18:16:17 +0200
Subject: [PATCH] Prevent notice during accessing "cached magnification factor"
 offset

Sheet View Settings Block should be 8-14 bytes long in BIFF8 Excel 97 according
to the open office file format documentation. However access to byte 10 and 12 is
not possible when record data is malformed, so getUInt2d throws notice.
---
 CHANGELOG.md                      |  1 +
 src/PhpSpreadsheet/Reader/Xls.php | 15 +++++++++++++--
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b3dd17a4..a3f149df 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -26,6 +26,7 @@ and this project adheres to [Semantic Versioning](https://semver.org).
 ### Fixed
 
 - Ensure that the list of shared formulae is maintained when an xlsx file is chunked with readFilter[Issue #169](https://github.com/PHPOffice/PhpSpreadsheet/issues/1669).
+- Fix for notice during accessing "cached magnification factor" offset [#1354](https://github.com/PHPOffice/PhpSpreadsheet/pull/1354)
 
 ## 1.15.0 - 2020-10-11
 
diff --git a/src/PhpSpreadsheet/Reader/Xls.php b/src/PhpSpreadsheet/Reader/Xls.php
index 81cc5b2e..b5c92d8d 100644
--- a/src/PhpSpreadsheet/Reader/Xls.php
+++ b/src/PhpSpreadsheet/Reader/Xls.php
@@ -4377,11 +4377,22 @@ class Xls extends BaseReader
             // offset: 10; size: 2; cached magnification factor in page break preview (in percent); 0 = Default (60%)
             // offset: 12; size: 2; cached magnification factor in normal view (in percent); 0 = Default (100%)
             // offset: 14; size: 4; not used
-            $zoomscaleInPageBreakPreview = self::getUInt2d($recordData, 10);
+            if (!isset($recordData[10])) {
+                $zoomscaleInPageBreakPreview = 0;
+            } else {
+                $zoomscaleInPageBreakPreview = self::getUInt2d($recordData, 10);
+            }
+
             if ($zoomscaleInPageBreakPreview === 0) {
                 $zoomscaleInPageBreakPreview = 60;
             }
-            $zoomscaleInNormalView = self::getUInt2d($recordData, 12);
+
+            if (!isset($recordData[12])) {
+                $zoomscaleInNormalView = 0;
+            } else {
+                $zoomscaleInNormalView = self::getUInt2d($recordData, 12);
+            }
+
             if ($zoomscaleInNormalView === 0) {
                 $zoomscaleInNormalView = 100;
             }