From 0484f1ef01766fa3a1e0f7a259935ae7799f0dee Mon Sep 17 00:00:00 2001
From: Tim Hunt <T.J.Hunt@open.ac.uk>
Date: Tue, 8 Mar 2011 16:52:38 +0000
Subject: [PATCH] MDL-21446 truncate >31 char worksheet names that otherwise
 break Excel export.

---
 lib/excellib.class.php | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/lib/excellib.class.php b/lib/excellib.class.php
index 1addd11499b..def025c74ab 100644
--- a/lib/excellib.class.php
+++ b/lib/excellib.class.php
@@ -138,6 +138,15 @@ class MoodleExcelWorksheet {
      */
     function MoodleExcelWorksheet($name, &$workbook, $latin_output=false) {
 
+        if (strlen($name) > 31) {
+            // Excel does not seem able to cope with sheet names > 31 chars.
+            // With $latin_output = false, it does not cope at all.
+            // With $latin_output = true it is supposed to work, but in our experience,
+            // it doesn't. Therefore, truncate in all circumstances.
+            $textlib = textlib_get_instance();
+            $name = $textlib->substr($name, 0, 31);
+        }
+
     /// Internally, add one sheet to the workbook
         $this->pear_excel_worksheet =& $workbook->addWorksheet($name);
         $this->latin_output = $latin_output;