From dbe5daaad3ffa049497c18030ca1f12628fa9057 Mon Sep 17 00:00:00 2001
From: Dieter Adriaenssens <ruleant@users.sourceforge.net>
Date: Wed, 14 Jul 2010 22:29:26 +0200
Subject: [PATCH] Converting number of Excel column names no longer limited

---
 ChangeLog                |  2 +-
 libraries/import.lib.php | 68 +++++++++++++++++++++++++++++-------------------
 2 files changed, 42 insertions(+), 28 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index fe595fd417..2b0c93fbc0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -19,7 +19,7 @@ $HeadURL: https://phpmyadmin.svn.sourceforge.net/svnroot/phpmyadmin/trunk/phpMyA
 - bug #3023507 [core] No result set display from stored procedure SELECT
 - bug [export] CSV for MS Excel (Windows) should have semi-colon as separator
 - [core] Update library PHPExcel to version 1.7.3c
-- bug #2994885 [import] Convert Excel column name correctly
+- bug #2994885, bug #3029168 [import] Convert Excel column name correctly
 
 3.3.4.0 (2010-06-28)
 - bug #2996161 [import] properly escape import value
diff --git a/libraries/import.lib.php b/libraries/import.lib.php
index 70e5f13852..6c039bd6e7 100644
--- a/libraries/import.lib.php
+++ b/libraries/import.lib.php
@@ -303,9 +303,19 @@ function PMA_importGetNextChunk($size = 32768)
 
 /**
  * Returns the "Excel" column name (i.e. 1 = "A", 26 = "Z", 27 = "AA", etc.)
- * This algorithm only works up to ZZ. it fails on AAA (up to 701 columns) 
  *
- * @author  Derek Schaefer (derek.schaefer@gmail.com)
+ * This functions uses recursion to build the Excel column name.
+ *
+ * The column number (1-26) is converted to the responding ASCII character (A-Z) and returned.
+ *
+ * If the column number is bigger than 26 (= num of letters in alfabet),
+ * an extra character needs to be added. To find this extra character, the number is divided by 26 
+ * and this value is passed to another instance of the same function (hence recursion). 
+ * In that new instance the number is evaluated again, and if it is still bigger than 26, it is divided again 
+ * and passed to another instance of the same function. This continues until the number is smaller than 26.
+ * Then the last called function returns the corresponding ASCII character to the function that called it.
+ * Each time a called function ends an extra character is added to the column name.
+ * When the first function is reached, the last character is addded and the complete column name is returned.
  *
  * @access  public
  *
@@ -315,31 +325,35 @@ function PMA_importGetNextChunk($size = 32768)
  */
 function PMA_getColumnAlphaName($num)
 {
-    /* ASCII value for capital "A" */
-    $A = 65;
-    $sCol = "";
-    $iRemain = 0;
-    
-    /* This algorithm only works up to ZZ. it fails on AAA */
-    
-    if ($num > 701) {                
-        return $num;
-    } elseif ($num <= 26) {
-        if ($num == 0) {
-            $sCol = chr(($A + 26) - 1);
-        } else {
-            $sCol = chr(($A + $num) - 1);
-        }
-    } else {
-        $iRemain = (($num / 26)) - 1;
-        if (($num % 26) == 0) {
-            $sCol = PMA_getColumnAlphaName($iRemain) . PMA_getColumnAlphaName($num % 26);
-        } else {
-            $sCol = chr($A + $iRemain) . PMA_getColumnAlphaName($num % 26);
-        }
-    }
-    
-    return $sCol;
+	$A = 65; // ASCII value for capital "A"
+	$col_name = "";
+
+	if ($num > 26) {
+		$div = (int)($num / 26);
+		$remain = (int)($num % 26);
+
+		// subtract 1 of divided value in case the modulus is 0,
+		// this is necessary because A-Z has no 'zero'
+		if ($remain == 0) {
+			$div--;
+		}
+
+		// recursive function call
+		$col_name = PMA_getColumnAlphaName($div);
+		// use modulus as new column number
+		$num = $remain;
+	}
+
+	if ($num == 0) {
+		// use 'Z' if column number is 0,
+		// this is necessary because A-Z has no 'zero'
+		$col_name .= chr(($A + 26) - 1);
+	} else {
+		// convert column number to ASCII character
+		$col_name .= chr(($A + $num) - 1);
+	}
+
+	return $col_name;
 }
 
 /**
-- 
2.11.4.GIT