Update Writer folder structure to match Reader new structure

src/Spout/Writer/XLSX/Helper/ZipHelper.php

@@ -0,0 +1,62 @@
+<?php
+
+namespace Box\Spout\Writer\XLSX\Helper;
+
+/**
+ * Class ZipHelper
+ * This class provides helper functions to create zip files
+ *
+ * @package Box\Spout\Writer\XLSX\Helper
+ */
+class ZipHelper
+{
+    /**
+     * Zips the given folder
+     *
+     * @param string $folderPath Path of the folder to be zipped
+     * @param string $destinationPath Path where the zip file will be created
+     * @return void
+     */
+    public function zipFolder($folderPath, $destinationPath)
+    {
+        $zip = new \ZipArchive();
+        if ($zip->open($destinationPath, \ZipArchive::CREATE)) {
+            $this->addFolderToZip($zip, $folderPath);
+            $zip->close();
+        }
+    }
+
+    /**
+     * @param \ZipArchive $zip
+     * @param string $folderPath Path of the folder to add to the zip
+     * @return void
+     */
+    protected function addFolderToZip($zip, $folderPath)
+    {
+        $folderRealPath = $this->getNormalizedRealPath($folderPath) . '/';
+        $itemIterator = new \RecursiveIteratorIterator(new \RecursiveDirectoryIterator($folderPath, \RecursiveDirectoryIterator::SKIP_DOTS), \RecursiveIteratorIterator::SELF_FIRST);
+
+        foreach ($itemIterator as $itemInfo) {
+            $itemRealPath = $this->getNormalizedRealPath($itemInfo->getPathname());
+            $itemLocalPath = str_replace($folderRealPath, '', $itemRealPath);
+
+            if ($itemInfo->isFile()) {
+                $zip->addFile($itemRealPath, $itemLocalPath);
+            } else if ($itemInfo->isDir()) {
+                $zip->addEmptyDir($itemLocalPath);
+            }
+        }
+    }
+
+    /**
+     * Returns canonicalized absolute pathname, containing only forward slashes.
+     *
+     * @param string $path Path to normalize
+     * @return string Normalized and canonicalized path
+     */
+    protected function getNormalizedRealPath($path)
+    {
+        $realPath = realpath($path);
+        return str_replace(DIRECTORY_SEPARATOR, '/', $realPath);
+    }
+}