From 0fddcc184ddd22fa2f66a9b641e384c47a51623c Mon Sep 17 00:00:00 2001
From: oleibman <10341515+oleibman@users.noreply.github.com>
Date: Tue, 5 Dec 2023 21:10:02 -0800
Subject: [PATCH] Performance Improvement for Xlsx Reader (#3810)

* Performance Improvement for Xlsx Reader

Fix #3683. PR #3497 fixed a problem involving formulas and the quotePrefix style attribute. It did so by automatically turning off quotePrefix for any formulas encountered by Xlsx Reader. Under the right circumstances, it turns out that that change can cause a file read to take noticeably more time than previously. This change will turn off quotePrefix only if it is already on, and that appears to eliminate the performance problem while continuing to solve the original problem.

* Very Minor Improvement

* Update CHANGELOG.md
---
 CHANGELOG.md                       | 2 ++
 src/PhpSpreadsheet/Reader/Xlsx.php | 6 +++---
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index bac167f9b7..76f9746d41 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -77,6 +77,8 @@ and this project adheres to [Semantic Versioning](https://semver.org).
 - Slk Shared Formulas. [Issue #2267](https://github.com/PHPOffice/PhpSpreadsheet/issues/2267) [PR #3776](https://github.com/PHPOffice/PhpSpreadsheet/pull/3776)
 - Html omitting some charts. [Issue #3767](https://github.com/PHPOffice/PhpSpreadsheet/issues/3767) [PR #3771](https://github.com/PHPOffice/PhpSpreadsheet/pull/3771)
 - Case Insensitive Comparison for Sheet Names [PR #3791](https://github.com/PHPOffice/PhpSpreadsheet/pull/3791)
+- Performance improvement for Xlsx Reader. [Issue #3683](https://github.com/PHPOffice/PhpSpreadsheet/issues/3683) [PR #3810](https://github.com/PHPOffice/PhpSpreadsheet/pull/3810)
+- Prevent loop in Shared/File. [Issue #3807](https://github.com/PHPOffice/PhpSpreadsheet/issues/3807) [PR #3809](https://github.com/PHPOffice/PhpSpreadsheet/pull/3809)
 
 ## 1.29.0 - 2023-06-15
 
diff --git a/src/PhpSpreadsheet/Reader/Xlsx.php b/src/PhpSpreadsheet/Reader/Xlsx.php
index 109a593edf..d9b60146e7 100644
--- a/src/PhpSpreadsheet/Reader/Xlsx.php
+++ b/src/PhpSpreadsheet/Reader/Xlsx.php
@@ -937,10 +937,10 @@ protected function loadSpreadsheetFromFile(string $filename): Spreadsheet
                                                 $holdSelected = $docSheet->getSelectedCells();
                                                 $cAttrS = (int) ($cAttr['s'] ?? 0);
                                                 // no style index means 0, it seems
-                                                $cell->setXfIndex(isset($styles[$cAttrS])
-                                                    ? $cAttrS : 0);
+                                                $cAttrS = isset($styles[$cAttrS]) ? $cAttrS : 0;
+                                                $cell->setXfIndex($cAttrS);
                                                 // issue 3495
-                                                if ($cell->getDataType() === DataType::TYPE_FORMULA) {
+                                                if ($cellDataType === DataType::TYPE_FORMULA && $styles[$cAttrS]->quotePrefix === true) {
                                                     $cell->getStyle()->setQuotePrefix(false);
                                                 }
                                                 $docSheet->setSelectedCells($holdSelected);