Support missing attribute `r` in `c` node when reading xlsx

When describing a cell, the cell reference (r="A1") is optional.
When not present, we should just increment the index of the last processed row.

Fixes #201 
Closes #225

CHANGELOG.md

@@ -21,6 +21,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 - Control characters in cell values are automatically escaped - [#212](https://github.com/PHPOffice/PhpSpreadsheet/issues/212)
 - Prevent color changing when copy/pasting xls files written by PhpSpreadsheet to another file - @al-lala [#218](https://github.com/PHPOffice/PhpSpreadsheet/issues/218)
+- Add cell reference automatic when there is no cell reference('r' attribute) in Xlsx file. - @GreatHumorist [#225](https://github.com/PHPOffice/PhpSpreadsheet/pull/225) Refer to [issue#201](https://github.com/PHPOffice/PhpSpreadsheet/issues/201)
 
 ### BREAKING CHANGE
 

src/PhpSpreadsheet/Reader/Xlsx.php

@@ -848,6 +848,7 @@ class Xlsx extends BaseReader implements IReader
                             }
 
                             if ($xmlSheet && $xmlSheet->sheetData && $xmlSheet->sheetData->row) {
+                                $cIndex = 1; // Cell Start from 1
                                 foreach ($xmlSheet->sheetData->row as $row) {
                                     if ($row['ht'] && !$this->readDataOnly) {
                                         $docSheet->getRowDimension((int) ($row['r']))->setRowHeight((float) ($row['ht']));
@@ -865,8 +866,12 @@ class Xlsx extends BaseReader implements IReader
                                         $docSheet->getRowDimension((int) ($row['r']))->setXfIndex((int) ($row['s']));
                                     }
 
+                                    $rowIndex = 0; // Start form zero because Cell::stringFromColumnIndex start from A default, actually is 1
                                     foreach ($row->c as $c) {
                                         $r = (string) $c['r'];
+                                        if ($r == '') {
+                                            $r = Cell::stringFromColumnIndex($rowIndex) . $cIndex;
+                                        }
                                         $cellDataType = (string) $c['t'];
                                         $value = null;
                                         $calculatedValue = null;
@@ -963,7 +968,9 @@ class Xlsx extends BaseReader implements IReader
                                             $cell->setXfIndex(isset($styles[(int) ($c['s'])]) ?
                                                 (int) ($c['s']) : 0);
                                         }
+                                        $rowIndex += 1;
                                     }
+                                    $cIndex += 1;
                                 }
                             }
 

tests/PhpSpreadsheetTests/Reader/XLSXTest.php

@@ -0,0 +1,19 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Reader;
+
+use PhpOffice\PhpSpreadsheet\Reader\Xlsx;
+use PHPUnit_Framework_TestCase;
+
+class XLSXTest extends PHPUnit_Framework_TestCase
+{
+    /**
+     * Test load Xlsx file without cell reference.
+     */
+    public function testLoadXlsxWithoutCellReference()
+    {
+        $filename = './data/Reader/XLSX/without_cell_reference.xlsx';
+        $reader = new Xlsx();
+        $reader->load($filename);
+    }
+}