From a281bee7d69f5347500e96e9df572e9ac5e7af15 Mon Sep 17 00:00:00 2001
From: Stefan <nimmneun@gmail.com>
Date: Fri, 2 Sep 2016 00:26:07 +0200
Subject: [PATCH] Improved XLSX Escaper performance for strings with only
 common/safe characters.

---
 src/Spout/Common/Escaper/XLSX.php | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/Spout/Common/Escaper/XLSX.php b/src/Spout/Common/Escaper/XLSX.php
index b5719a0..acd66bf 100644
--- a/src/Spout/Common/Escaper/XLSX.php
+++ b/src/Spout/Common/Escaper/XLSX.php
@@ -95,6 +95,10 @@ class XLSX implements EscaperInterface
      */
     protected function escapeControlCharacters($string)
     {
+        if (1 !== preg_match('~[^A-Za-z0-9\-.:, ]~', $string)) {
+            return $string;
+        }
+
         $escapedString = $this->escapeEscapeCharacter($string);
         return str_replace(array_values($this->controlCharactersEscapingMap), array_keys($this->controlCharactersEscapingMap), $escapedString);
     }