Update Writer folder structure to match Reader new structure

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

@@ -0,0 +1,71 @@
+<?php
+
+namespace Box\Spout\Writer\XLSX\Helper;
+
+/**
+ * Class CellHelper
+ * This class provides helper functions when working with cells
+ *
+ * @package Box\Spout\Writer\XLSX\Helper
+ */
+class CellHelper
+{
+    /**
+     * Returns the cell index (base 26) associated to the base 10 column index.
+     * Excel uses A to Z letters for column indexing, where A is the 1st column,
+     * Z is the 26th and AA is the 27th.
+     * The mapping is zero based, so that 0 maps to A, B maps to 1, Z to 25 and AA to 26.
+     *
+     * @param int $columnIndex The Excel column index (0, 42, ...)
+     * @return string The associated cell index ('A', 'BC', ...)
+     */
+    public static function getCellIndexFromColumnIndex($columnIndex)
+    {
+        $cellIndex = '';
+        $capitalAAsciiValue = ord('A');
+
+        do {
+            $modulus = $columnIndex % 26;
+            $cellIndex = chr($capitalAAsciiValue + $modulus) . $cellIndex;
+
+            // substracting 1 because it's zero-based
+            $columnIndex = intval($columnIndex / 26) - 1;
+        } while ($columnIndex >= 0);
+
+        return $cellIndex;
+    }
+
+    /**
+     * @param $value
+     * @return bool Whether the given value is a non empty string
+     */
+    public static function isNonEmptyString($value)
+    {
+        return (gettype($value) === 'string' && $value !== '');
+    }
+
+    /**
+     * Returns whether the given value is numeric.
+     * A numeric value is from type "integer" or "double" ("float" is not returned by gettype).
+     *
+     * @param $value
+     * @return bool Whether the given value is numeric
+     */
+    public static function isNumeric($value)
+    {
+        $valueType = gettype($value);
+        return ($valueType === 'integer' || $valueType === 'double');
+    }
+
+    /**
+     * Returns whether the given value is boolean.
+     * "true"/"false" and 0/1 are not booleans.
+     *
+     * @param $value
+     * @return bool Whether the given value is boolean
+     */
+    public static function isBoolean($value)
+    {
+        return gettype($value) === 'boolean';
+    }
+}

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

@@ -0,0 +1,378 @@
+<?php
+
+namespace Box\Spout\Writer\XLSX\Helper;
+
+use Box\Spout\Writer\XLSX\Internal\Worksheet;
+
+/**
+ * Class FileSystemHelper
+ * This class provides helper functions to help with the file system operations
+ * like files/folders creation & deletion for XLSX files
+ *
+ * @package Box\Spout\Writer\XLSX\Helper
+ */
+class FileSystemHelper extends \Box\Spout\Common\Helper\FileSystemHelper
+{
+    const APP_NAME = 'Spout';
+
+    const RELS_FOLDER_NAME = '_rels';
+    const DOC_PROPS_FOLDER_NAME = 'docProps';
+    const XL_FOLDER_NAME = 'xl';
+    const WORKSHEETS_FOLDER_NAME = 'worksheets';
+
+    const RELS_FILE_NAME = '.rels';
+    const APP_XML_FILE_NAME = 'app.xml';
+    const CORE_XML_FILE_NAME = 'core.xml';
+    const CONTENT_TYPES_XML_FILE_NAME = '[Content_Types].xml';
+    const WORKBOOK_XML_FILE_NAME = 'workbook.xml';
+    const WORKBOOK_RELS_XML_FILE_NAME = 'workbook.xml.rels';
+
+    /** @var string Path to the root folder inside the temp folder where the files to create the XLSX will be stored */
+    protected $rootFolder;
+
+    /** @var string Path to the "_rels" folder inside the root folder */
+    protected $relsFolder;
+
+    /** @var string Path to the "docProps" folder inside the root folder */
+    protected $docPropsFolder;
+
+    /** @var string Path to the "xl" folder inside the root folder */
+    protected $xlFolder;
+
+    /** @var string Path to the "_rels" folder inside the "xl" folder */
+    protected $xlRelsFolder;
+
+    /** @var string Path to the "worksheets" folder inside the "xl" folder */
+    protected $xlWorksheetsFolder;
+
+    /**
+     * @return string
+     */
+    public function getRootFolder()
+    {
+        return $this->rootFolder;
+    }
+
+    /**
+     * @return string
+     */
+    public function getXlFolder()
+    {
+        return $this->xlFolder;
+    }
+
+    /**
+     * @return string
+     */
+    public function getXlWorksheetsFolder()
+    {
+        return $this->xlWorksheetsFolder;
+    }
+
+    /**
+     * Creates all the folders needed to create a XLSX file, as well as the files that won't change.
+     *
+     * @return void
+     * @throws \Box\Spout\Common\Exception\IOException If unable to create at least one of the base folders
+     */
+    public function createBaseFilesAndFolders()
+    {
+        $this
+            ->createRootFolder()
+            ->createRelsFolderAndFile()
+            ->createDocPropsFolderAndFiles()
+            ->createXlFolderAndSubFolders();
+    }
+
+    /**
+     * Creates the folder that will be used as root
+     *
+     * @return FileSystemHelper
+     * @throws \Box\Spout\Common\Exception\IOException If unable to create the folder
+     */
+    protected function createRootFolder()
+    {
+        $this->rootFolder = $this->createFolder($this->baseFolderPath, uniqid('xlsx'));
+        return $this;
+    }
+
+    /**
+     * Creates the "_rels" folder under the root folder as well as the ".rels" file in it
+     *
+     * @return FileSystemHelper
+     * @throws \Box\Spout\Common\Exception\IOException If unable to create the folder or the ".rels" file
+     */
+    protected function createRelsFolderAndFile()
+    {
+        $this->relsFolder = $this->createFolder($this->rootFolder, self::RELS_FOLDER_NAME);
+
+        $this->createRelsFile();
+
+        return $this;
+    }
+
+    /**
+     * Creates the ".rels" file under the "_rels" folder (under root)
+     *
+     * @return FileSystemHelper
+     * @throws \Box\Spout\Common\Exception\IOException If unable to create the file
+     */
+    protected function createRelsFile()
+    {
+        $relsFileContents = <<<EOD
+<?xml version="1.0" encoding="UTF-8"?>
+<Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships">
+    <Relationship Id="rIdWorkbook" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/officeDocument" Target="xl/workbook.xml"/>
+    <Relationship Id="rIdCore" Type="http://schemas.openxmlformats.org/officedocument/2006/relationships/metadata/core-properties" Target="docProps/core.xml"/>
+    <Relationship Id="rIdApp" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/extended-properties" Target="docProps/app.xml"/>
+</Relationships>
+EOD;
+
+        $this->createFileWithContents($this->relsFolder, self::RELS_FILE_NAME, $relsFileContents);
+
+        return $this;
+    }
+
+    /**
+     * Creates the "docProps" folder under the root folder as well as the "app.xml" and "core.xml" files in it
+     *
+     * @return FileSystemHelper
+     * @throws \Box\Spout\Common\Exception\IOException If unable to create the folder or one of the files
+     */
+    protected function createDocPropsFolderAndFiles()
+    {
+        $this->docPropsFolder = $this->createFolder($this->rootFolder, self::DOC_PROPS_FOLDER_NAME);
+
+        $this->createAppXmlFile();
+        $this->createCoreXmlFile();
+
+        return $this;
+    }
+
+    /**
+     * Creates the "app.xml" file under the "docProps" folder
+     *
+     * @return FileSystemHelper
+     * @throws \Box\Spout\Common\Exception\IOException If unable to create the file
+     */
+    protected function createAppXmlFile()
+    {
+        $appName = self::APP_NAME;
+        $appXmlFileContents = <<<EOD
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<Properties xmlns="http://schemas.openxmlformats.org/officeDocument/2006/extended-properties">
+    <Application>$appName</Application>
+    <TotalTime>0</TotalTime>
+</Properties>
+EOD;
+
+        $this->createFileWithContents($this->docPropsFolder, self::APP_XML_FILE_NAME, $appXmlFileContents);
+
+        return $this;
+    }
+
+    /**
+     * Creates the "core.xml" file under the "docProps" folder
+     *
+     * @return FileSystemHelper
+     * @throws \Box\Spout\Common\Exception\IOException If unable to create the file
+     */
+    protected function createCoreXmlFile()
+    {
+        $createdDate = (new \DateTime())->format('c');
+        $coreXmlFileContents = <<<EOD
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<cp:coreProperties xmlns:cp="http://schemas.openxmlformats.org/package/2006/metadata/core-properties" xmlns:dcmitype="http://purl.org/dc/dcmitype/" xmlns:dcterms="http://purl.org/dc/terms/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+    <dcterms:created xsi:type="dcterms:W3CDTF">$createdDate</dcterms:created>
+    <dcterms:modified xsi:type="dcterms:W3CDTF">$createdDate</dcterms:modified>
+    <cp:revision>0</cp:revision>
+</cp:coreProperties>
+EOD;
+
+        $this->createFileWithContents($this->docPropsFolder, self::CORE_XML_FILE_NAME, $coreXmlFileContents);
+
+        return $this;
+    }
+
+    /**
+     * Creates the "xl" folder under the root folder as well as its subfolders
+     *
+     * @return FileSystemHelper
+     * @throws \Box\Spout\Common\Exception\IOException If unable to create at least one of the folders
+     */
+    protected function createXlFolderAndSubFolders()
+    {
+        $this->xlFolder = $this->createFolder($this->rootFolder, self::XL_FOLDER_NAME);
+        $this->createXlRelsFolder();
+        $this->createXlWorksheetsFolder();
+
+        return $this;
+    }
+
+    /**
+     * Creates the "_rels" folder under the "xl" folder
+     *
+     * @return FileSystemHelper
+     * @throws \Box\Spout\Common\Exception\IOException If unable to create the folder
+     */
+    protected function createXlRelsFolder()
+    {
+        $this->xlRelsFolder = $this->createFolder($this->xlFolder, self::RELS_FOLDER_NAME);
+        return $this;
+    }
+
+    /**
+     * Creates the "worksheets" folder under the "xl" folder
+     *
+     * @return FileSystemHelper
+     * @throws \Box\Spout\Common\Exception\IOException If unable to create the folder
+     */
+    protected function createXlWorksheetsFolder()
+    {
+        $this->xlWorksheetsFolder = $this->createFolder($this->xlFolder, self::WORKSHEETS_FOLDER_NAME);
+        return $this;
+    }
+
+    /**
+     * Creates the "[Content_Types].xml" file under the root folder
+     *
+     * @param Worksheet[] $worksheets
+     * @return FileSystemHelper
+     */
+    public function createContentTypesFile($worksheets)
+    {
+        $contentTypesXmlFileContents = <<<EOD
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<Types xmlns="http://schemas.openxmlformats.org/package/2006/content-types">
+    <Default ContentType="application/xml" Extension="xml"/>
+    <Default ContentType="application/vnd.openxmlformats-package.relationships+xml" Extension="rels"/>
+    <Override ContentType="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet.main+xml" PartName="/xl/workbook.xml"/>
+
+EOD;
+
+    /** @var Worksheet $worksheet */
+    foreach ($worksheets as $worksheet) {
+        $contentTypesXmlFileContents .= '    <Override ContentType="application/vnd.openxmlformats-officedocument.spreadsheetml.worksheet+xml" PartName="/xl/worksheets/sheet' . $worksheet->getId() . '.xml"/>' . PHP_EOL;
+    }
+
+    $contentTypesXmlFileContents .= <<<EOD
+    <Override ContentType="application/vnd.openxmlformats-officedocument.spreadsheetml.sharedStrings+xml" PartName="/xl/sharedStrings.xml"/>
+    <Override ContentType="application/vnd.openxmlformats-package.core-properties+xml" PartName="/docProps/core.xml"/>
+    <Override ContentType="application/vnd.openxmlformats-officedocument.extended-properties+xml" PartName="/docProps/app.xml"/>
+</Types>
+EOD;
+
+        $this->createFileWithContents($this->rootFolder, self::CONTENT_TYPES_XML_FILE_NAME, $contentTypesXmlFileContents);
+
+        return $this;
+    }
+
+    /**
+     * Creates the "workbook.xml" file under the "xl" folder
+     *
+     * @param Worksheet[] $worksheets
+     * @return FileSystemHelper
+     */
+    public function createWorkbookFile($worksheets)
+    {
+        $workbookXmlFileContents = <<<EOD
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<workbook xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships">
+    <sheets>
+
+EOD;
+
+        $escaper = new \Box\Spout\Common\Escaper\XLSX();
+
+        /** @var Worksheet $worksheet */
+        foreach ($worksheets as $worksheet) {
+            $worksheetName = $worksheet->getExternalSheet()->getName();
+            $worksheetId = $worksheet->getId();
+            $workbookXmlFileContents .= '        <sheet name="' . $escaper->escape($worksheetName) . '" sheetId="' . $worksheetId . '" r:id="rIdSheet' . $worksheetId . '"/>' . PHP_EOL;
+        }
+
+        $workbookXmlFileContents .= <<<EOD
+    </sheets>
+</workbook>
+EOD;
+
+        $this->createFileWithContents($this->xlFolder, self::WORKBOOK_XML_FILE_NAME, $workbookXmlFileContents);
+
+        return $this;
+    }
+
+    /**
+     * Creates the "workbook.xml.res" file under the "xl/_res" folder
+     *
+     * @param Worksheet[] $worksheets
+     * @return FileSystemHelper
+     */
+    public function createWorkbookRelsFile($worksheets)
+    {
+        $workbookRelsXmlFileContents = <<<EOD
+<?xml version="1.0" encoding="UTF-8"?>
+<Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships">
+    <Relationship Id="rIdSharedStrings" Target="sharedStrings.xml" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/sharedStrings"/>
+
+EOD;
+
+        /** @var Worksheet $worksheet */
+        foreach ($worksheets as $worksheet) {
+            $worksheetId = $worksheet->getId();
+            $workbookRelsXmlFileContents .= '    <Relationship Id="rIdSheet' . $worksheetId . '" Target="worksheets/sheet' . $worksheetId . '.xml" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/worksheet"/>' . PHP_EOL;
+        }
+
+        $workbookRelsXmlFileContents .= '</Relationships>';
+
+        $this->createFileWithContents($this->xlRelsFolder, self::WORKBOOK_RELS_XML_FILE_NAME, $workbookRelsXmlFileContents);
+
+        return $this;
+    }
+
+    /**
+     * Zips the root folder and streams the contents of the zip into the given stream
+     *
+     * @param resource $streamPointer Pointer to the stream to copy the zip
+     * @return void
+     */
+    public function zipRootFolderAndCopyToStream($streamPointer)
+    {
+        $this->zipRootFolder();
+        $this->copyZipToStream($streamPointer);
+
+        // once the zip is copied, remove it
+        $this->deleteFile($this->getZipFilePath());
+    }
+
+    /**
+     * Zips the root folder
+     *
+     * @return void
+     */
+    protected function zipRootFolder()
+    {
+        $zipHelper = new ZipHelper();
+        $zipHelper->zipFolder($this->rootFolder, $this->getZipFilePath());
+    }
+
+    /**
+     * @return string Path of the zip file created from the root folder
+     */
+    protected function getZipFilePath()
+    {
+        return $this->rootFolder . '.zip';
+    }
+
+    /**
+     * Streams the contents of the zip into the given stream
+     *
+     * @param resource $pointer Pointer to the stream to copy the zip
+     * @return void
+     */
+    protected function copyZipToStream($pointer)
+    {
+        $zipFilePointer = fopen($this->getZipFilePath(), 'r');
+        stream_copy_to_stream($zipFilePointer, $pointer);
+        fclose($zipFilePointer);
+    }
+}

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

@@ -0,0 +1,99 @@
+<?php
+
+namespace Box\Spout\Writer\XLSX\Helper;
+
+use Box\Spout\Common\Exception\IOException;
+
+/**
+ * Class SharedStringsHelper
+ * This class provides helper functions to write shared strings
+ *
+ * @package Box\Spout\Writer\XLSX\Helper
+ */
+class SharedStringsHelper
+{
+    const SHARED_STRINGS_FILE_NAME = 'sharedStrings.xml';
+
+    const SHARED_STRINGS_XML_FILE_FIRST_PART_HEADER = <<<EOD
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<sst xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main"
+EOD;
+
+    /**
+     * This number must be really big so that the no generated file will have more strings than that.
+     * If the strings number goes above, characters will be overwritten in an unwanted way and will corrupt the file.
+     */
+    const DEFAULT_STRINGS_COUNT_PART = 'count="9999999999999" uniqueCount="9999999999999"';
+
+    /** @var int Number of shared strings already written */
+    protected $numSharedStrings = 0;
+
+    /** @var \Box\Spout\Common\Escaper\XLSX Strings escaper */
+    protected $stringsEscaper;
+
+    /**
+     * @param string $xlFolder Path to the "xl" folder
+     */
+    public function __construct($xlFolder)
+    {
+        $sharedStringsFilePath = $xlFolder . '/' . self::SHARED_STRINGS_FILE_NAME;
+        $this->sharedStringsFilePointer = fopen($sharedStringsFilePath, 'w');
+
+        $this->throwIfSharedStringsFilePointerIsNotAvailable();
+
+        // the headers is split into different parts so that we can fseek and put in the correct count and uniqueCount later
+        $header = self::SHARED_STRINGS_XML_FILE_FIRST_PART_HEADER . ' ' . self::DEFAULT_STRINGS_COUNT_PART . '>' . PHP_EOL;
+        fwrite($this->sharedStringsFilePointer, $header);
+
+        $this->stringsEscaper = new \Box\Spout\Common\Escaper\XLSX();
+    }
+
+    /**
+     * Checks if the book has been created. Throws an exception if not created yet.
+     *
+     * @return void
+     * @throws \Box\Spout\Common\Exception\IOException If the sheet data file cannot be opened for writing
+     */
+    protected function throwIfSharedStringsFilePointerIsNotAvailable()
+    {
+        if (!$this->sharedStringsFilePointer) {
+            throw new IOException('Unable to open shared strings file for writing.');
+        }
+    }
+
+    /**
+     * Writes the given string into the sharedStrings.xml file.
+     * Starting and ending whitespaces are preserved.
+     *
+     * @param string $string
+     * @return int ID of the written shared string
+     */
+    public function writeString($string)
+    {
+        fwrite($this->sharedStringsFilePointer, '    <si><t xml:space="preserve">' . $this->stringsEscaper->escape($string) . '</t></si>' . PHP_EOL);
+        $this->numSharedStrings++;
+
+        // Shared string ID is zero-based
+        return ($this->numSharedStrings - 1);
+    }
+
+    /**
+     * Finishes writing the data in the sharedStrings.xml file and closes the file.
+     *
+     * @return void
+     */
+    public function close()
+    {
+        fwrite($this->sharedStringsFilePointer, '</sst>');
+
+        // Replace the default strings count with the actual number of shared strings in the file header
+        $firstPartHeaderLength = strlen(self::SHARED_STRINGS_XML_FILE_FIRST_PART_HEADER);
+        $defaultStringsCountPartLength = strlen(self::DEFAULT_STRINGS_COUNT_PART);
+
+        // Adding 1 to take into account the space between the last xml attribute and "count"
+        fseek($this->sharedStringsFilePointer, $firstPartHeaderLength + 1);
+        fwrite($this->sharedStringsFilePointer, sprintf("%-{$defaultStringsCountPartLength}s", 'count="' . $this->numSharedStrings . '" uniqueCount="' . $this->numSharedStrings . '"'));
+
+        fclose($this->sharedStringsFilePointer);
+    }
+}

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);
+    }
+}

src/Spout/Writer/XLSX/Internal/Workbook.php

@@ -0,0 +1,235 @@
+<?php
+
+namespace Box\Spout\Writer\XLSX\Internal;
+
+use Box\Spout\Writer\Exception\SheetNotFoundException;
+use Box\Spout\Writer\XLSX\Helper\FileSystemHelper;
+use Box\Spout\Writer\XLSX\Helper\SharedStringsHelper;
+use Box\Spout\Writer\XLSX\Sheet;
+
+/**
+ * Class Book
+ * Represents a workbook within a XLSX file.
+ * It provides the functions to work with worksheets.
+ *
+ * @package Box\Spout\Writer\XLSX\Internal
+ */
+class Workbook
+{
+    /**
+     * Maximum number of rows a XLSX sheet can contain
+     * @see http://office.microsoft.com/en-us/excel-help/excel-specifications-and-limits-HP010073849.aspx
+     */
+    protected static $maxRowsPerWorksheet = 1048576;
+
+    /** @var bool Whether inline or shared strings should be used */
+    protected $shouldUseInlineStrings;
+
+    /** @var bool Whether new sheets should be automatically created when the max rows limit per sheet is reached */
+    protected $shouldCreateNewSheetsAutomatically;
+
+    /** @var \Box\Spout\Writer\XLSX\Helper\FileSystemHelper Helper to perform file system operations */
+    protected $fileSystemHelper;
+
+    /** @var \Box\Spout\Writer\XLSX\Helper\SharedStringsHelper Helper to write shared strings */
+    protected $sharedStringsHelper;
+
+    /** @var Worksheet[] Array containing the workbook's sheets */
+    protected $worksheets = [];
+
+    /** @var Worksheet The worksheet where data will be written to */
+    protected $currentWorksheet;
+
+    /**
+     * @param string $tempFolder
+     * @param bool $shouldUseInlineStrings
+     * @param bool $shouldCreateNewSheetsAutomatically
+     * @throws \Box\Spout\Common\Exception\IOException If unable to create at least one of the base folders
+     */
+    public function __construct($tempFolder, $shouldUseInlineStrings, $shouldCreateNewSheetsAutomatically)
+    {
+        $this->shouldUseInlineStrings = $shouldUseInlineStrings;
+        $this->shouldCreateNewSheetsAutomatically = $shouldCreateNewSheetsAutomatically;
+
+        $this->fileSystemHelper = new FileSystemHelper($tempFolder);
+        $this->fileSystemHelper->createBaseFilesAndFolders();
+
+        // This helper will be shared by all sheets
+        $xlFolder = $this->fileSystemHelper->getXlFolder();
+        $this->sharedStringsHelper = new SharedStringsHelper($xlFolder);
+    }
+
+    /**
+     * Creates a new sheet in the workbook. The current sheet remains unchanged.
+     *
+     * @return Worksheet The created sheet
+     * @throws \Box\Spout\Common\Exception\IOException If unable to open the sheet for writing
+     */
+    public function addNewSheet()
+    {
+        $newSheetIndex = count($this->worksheets);
+        $sheet = new Sheet($newSheetIndex);
+
+        $worksheetFilesFolder = $this->fileSystemHelper->getXlWorksheetsFolder();
+        $worksheet = new Worksheet($sheet, $worksheetFilesFolder, $this->sharedStringsHelper, $this->shouldUseInlineStrings);
+        $this->worksheets[] = $worksheet;
+
+        return $worksheet;
+    }
+
+    /**
+     * Creates a new sheet in the workbook and make it the current sheet.
+     * The writing will resume where it stopped (i.e. data won't be truncated).
+     *
+     * @return Worksheet The created sheet
+     * @throws \Box\Spout\Common\Exception\IOException If unable to open the sheet for writing
+     */
+    public function addNewSheetAndMakeItCurrent()
+    {
+        $worksheet = $this->addNewSheet();
+        $this->setCurrentWorksheet($worksheet);
+
+        return $worksheet;
+    }
+
+    /**
+     * @return Worksheet[] All the workbook's sheets
+     */
+    public function getWorksheets()
+    {
+        return $this->worksheets;
+    }
+
+    /**
+     * Returns the current sheet
+     *
+     * @return Worksheet The current sheet
+     */
+    public function getCurrentWorksheet()
+    {
+        return $this->currentWorksheet;
+    }
+
+    /**
+     * Sets the given sheet as the current one. New data will be written to this sheet.
+     * The writing will resume where it stopped (i.e. data won't be truncated).
+     *
+     * @param \Box\Spout\Writer\XLSX\Sheet $sheet The "external" sheet to set as current
+     * @return void
+     * @throws \Box\Spout\Writer\Exception\SheetNotFoundException If the given sheet does not exist in the workbook
+     */
+    public function setCurrentSheet($sheet)
+    {
+        $worksheet = $this->getWorksheetFromExternalSheet($sheet);
+        if ($worksheet !== null) {
+            $this->currentWorksheet = $worksheet;
+        } else {
+            throw new SheetNotFoundException('The given sheet does not exist in the workbook.');
+        }
+    }
+
+    /**
+     * @param Worksheet $worksheet
+     * @return void
+     */
+    protected function setCurrentWorksheet($worksheet)
+    {
+        $this->currentWorksheet = $worksheet;
+    }
+
+    /**
+     * Returns the worksheet associated to the given external sheet.
+     *
+     * @param \Box\Spout\Writer\XLSX\Sheet $sheet
+     * @return Worksheet|null The worksheet associated to the given external sheet or null if not found.
+     */
+    protected function getWorksheetFromExternalSheet($sheet)
+    {
+        $worksheetFound = null;
+
+        foreach ($this->worksheets as $worksheet) {
+            if ($worksheet->getExternalSheet() == $sheet) {
+                $worksheetFound = $worksheet;
+                break;
+            }
+        }
+
+        return $worksheetFound;
+    }
+
+    /**
+     * Adds data to the current sheet.
+     * If shouldCreateNewSheetsAutomatically option is set to true, it will handle pagination
+     * with the creation of new worksheets if one worksheet has reached its maximum capicity.
+     *
+     * @param array $dataRow Array containing data to be written.
+     *          Example $dataRow = ['data1', 1234, null, '', 'data5'];
+     * @return void
+     * @throws \Box\Spout\Common\Exception\IOException If trying to create a new sheet and unable to open the sheet for writing
+     * @throws \Box\Spout\Writer\Exception\WriterException If unable to write data
+     */
+    public function addRowToCurrentWorksheet($dataRow)
+    {
+        $currentWorksheet = $this->getCurrentWorksheet();
+        $hasReachedMaxRows = $this->hasCurrentWorkseetReachedMaxRows();
+
+        // if we reached the maximum number of rows for the current sheet...
+        if ($hasReachedMaxRows) {
+            // ... continue writing in a new sheet if option set
+            if ($this->shouldCreateNewSheetsAutomatically) {
+                $currentWorksheet = $this->addNewSheetAndMakeItCurrent();
+                $currentWorksheet->addRow($dataRow);
+            } else {
+                // otherwise, do nothing as the data won't be read anyways
+            }
+        } else {
+            $currentWorksheet->addRow($dataRow);
+        }
+    }
+
+    /**
+     * @return bool Whether the current worksheet has reached the maximum number of rows per sheet.
+     */
+    protected function hasCurrentWorkseetReachedMaxRows()
+    {
+        $currentWorksheet = $this->getCurrentWorksheet();
+        return ($currentWorksheet->getLastWrittenRowIndex() >= self::$maxRowsPerWorksheet);
+    }
+
+    /**
+     * Closes the workbook and all its associated sheets.
+     * All the necessary files are written to disk and zipped together to create the XLSX file.
+     * All the temporary files are then deleted.
+     *
+     * @param resource $finalFilePointer Pointer to the XLSX that will be created
+     * @return void
+     */
+    public function close($finalFilePointer)
+    {
+        foreach ($this->worksheets as $worksheet) {
+            $worksheet->close();
+        }
+
+        $this->sharedStringsHelper->close();
+
+        // Finish creating all the necessary files before zipping everything together
+        $this->fileSystemHelper
+            ->createContentTypesFile($this->worksheets)
+            ->createWorkbookFile($this->worksheets)
+            ->createWorkbookRelsFile($this->worksheets)
+            ->zipRootFolderAndCopyToStream($finalFilePointer);
+
+        $this->cleanupTempFolder();
+    }
+
+    /**
+     * Deletes the root folder created in the temp folder and all its contents.
+     *
+     * @return void
+     */
+    protected function cleanupTempFolder()
+    {
+        $xlsxRootFolder = $this->fileSystemHelper->getRootFolder();
+        $this->fileSystemHelper->deleteFolderRecursively($xlsxRootFolder);
+    }
+}

src/Spout/Writer/XLSX/Internal/Worksheet.php

@@ -0,0 +1,177 @@
+<?php
+
+namespace Box\Spout\Writer\XLSX\Internal;
+
+use Box\Spout\Common\Exception\InvalidArgumentException;
+use Box\Spout\Common\Exception\IOException;
+use Box\Spout\Writer\XLSX\Helper\CellHelper;
+
+/**
+ * Class Worksheet
+ * Represents a worksheet within a XLSX file. The difference with the Sheet object is
+ * that this class provides an interface to write data
+ *
+ * @package Box\Spout\Writer\XLSX\Internal
+ */
+class Worksheet
+{
+    const SHEET_XML_FILE_HEADER = <<<EOD
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<worksheet xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships">
+EOD;
+
+    /** @var \Box\Spout\Writer\XLSX\Sheet The "external" sheet */
+    protected $externalSheet;
+
+    /** @var string Path to the XML file that will contain the sheet data */
+    protected $worksheetFilePath;
+
+    /** @var \Box\Spout\Writer\XLSX\Helper\SharedStringsHelper Helper to write shared strings */
+    protected $sharedStringsHelper;
+
+    /** @var bool Whether inline or shared strings should be used */
+    protected $shouldUseInlineStrings;
+
+    /** @var \Box\Spout\Common\Escaper\XLSX Strings escaper */
+    protected $stringsEscaper;
+
+    /** @var Resource Pointer to the sheet data file (e.g. xl/worksheets/sheet1.xml) */
+    protected $sheetFilePointer;
+
+    /** @var int */
+    protected $lastWrittenRowIndex = 0;
+
+    /**
+     * @param \Box\Spout\Writer\XLSX\Sheet $externalSheet The associated "external" sheet
+     * @param string $worksheetFilesFolder Temporary folder where the files to create the XLSX will be stored
+     * @param \Box\Spout\Writer\XLSX\Helper\SharedStringsHelper $sharedStringsHelper Helper for shared strings
+     * @param bool $shouldUseInlineStrings Whether inline or shared strings should be used
+     * @throws \Box\Spout\Common\Exception\IOException If the sheet data file cannot be opened for writing
+     */
+    public function __construct($externalSheet, $worksheetFilesFolder, $sharedStringsHelper, $shouldUseInlineStrings)
+    {
+        $this->externalSheet = $externalSheet;
+        $this->sharedStringsHelper = $sharedStringsHelper;
+        $this->shouldUseInlineStrings = $shouldUseInlineStrings;
+
+        $this->stringsEscaper = new \Box\Spout\Common\Escaper\XLSX();
+
+        $this->worksheetFilePath = $worksheetFilesFolder . '/' . strtolower($this->externalSheet->getName()) . '.xml';
+        $this->startSheet();
+    }
+
+    /**
+     * Prepares the worksheet to accept data
+     *
+     * @return void
+     * @throws \Box\Spout\Common\Exception\IOException If the sheet data file cannot be opened for writing
+     */
+    protected function startSheet()
+    {
+        $this->sheetFilePointer = fopen($this->worksheetFilePath, 'w');
+        $this->throwIfSheetFilePointerIsNotAvailable();
+
+        fwrite($this->sheetFilePointer, self::SHEET_XML_FILE_HEADER . PHP_EOL);
+        fwrite($this->sheetFilePointer, '    <sheetData>' . PHP_EOL);
+    }
+
+    /**
+     * @return \Box\Spout\Writer\XLSX\Sheet The "external" sheet
+     */
+    public function getExternalSheet()
+    {
+        return $this->externalSheet;
+    }
+
+    /**
+     * @return int The index of the last written row
+     */
+    public function getLastWrittenRowIndex()
+    {
+        return $this->lastWrittenRowIndex;
+    }
+
+    /**
+     * @return int The ID of the worksheet
+     */
+    public function getId()
+    {
+        // sheet index is zero-based, while ID is 1-based
+        return $this->externalSheet->getIndex() + 1;
+    }
+
+    /**
+     * Checks if the book has been created. Throws an exception if not created yet.
+     *
+     * @return void
+     * @throws \Box\Spout\Common\Exception\IOException If the sheet data file cannot be opened for writing
+     */
+    protected function throwIfSheetFilePointerIsNotAvailable()
+    {
+        if (!$this->sheetFilePointer) {
+            throw new IOException('Unable to open sheet for writing.');
+        }
+    }
+
+    /**
+     * Adds data to the worksheet.
+     *
+     * @param array $dataRow Array containing data to be written.
+     *          Example $dataRow = ['data1', 1234, null, '', 'data5'];
+     * @return void
+     * @throws \Box\Spout\Common\Exception\IOException If the data cannot be written
+     * @throws \Box\Spout\Common\Exception\InvalidArgumentException If a cell value's type is not supported
+     */
+    public function addRow($dataRow)
+    {
+        $cellNumber = 0;
+        $rowIndex = $this->lastWrittenRowIndex + 1;
+        $numCells = count($dataRow);
+
+        $data = '        <row r="' . $rowIndex . '" spans="1:' . $numCells . '">' . PHP_EOL;
+
+        foreach($dataRow as $cellValue) {
+            $columnIndex = CellHelper::getCellIndexFromColumnIndex($cellNumber);
+            $data .= '            <c r="' . $columnIndex . $rowIndex . '"';
+
+            if (CellHelper::isNonEmptyString($cellValue)) {
+                if ($this->shouldUseInlineStrings) {
+                    $data .= ' t="inlineStr"><is><t>' . $this->stringsEscaper->escape($cellValue) . '</t></is></c>' . PHP_EOL;
+                } else {
+                    $sharedStringId = $this->sharedStringsHelper->writeString($cellValue);
+                    $data .= ' t="s"><v>' . $sharedStringId . '</v></c>' . PHP_EOL;
+                }
+            } else if (CellHelper::isNumeric($cellValue) || CellHelper::isBoolean($cellValue)) {
+                $data .= '><v>' . $cellValue . '</v></c>' . PHP_EOL;
+            } else if (empty($cellValue)) {
+                $data .= '/>' . PHP_EOL;
+            } else {
+                throw new InvalidArgumentException('Trying to add a value with an unsupported type: ' . gettype($cellValue));
+            }
+
+            $cellNumber++;
+        }
+
+        $data .= '        </row>' . PHP_EOL;
+
+        $wasWriteSuccessful = fwrite($this->sheetFilePointer, $data);
+        if ($wasWriteSuccessful === false) {
+            throw new IOException('Unable to write data in ' . $this->worksheetFilePath);
+        }
+
+        // only update the count if the write worked
+        $this->lastWrittenRowIndex++;
+    }
+
+    /**
+     * Closes the worksheet
+     *
+     * @return void
+     */
+    public function close()
+    {
+        fwrite($this->sheetFilePointer, '    </sheetData>' . PHP_EOL);
+        fwrite($this->sheetFilePointer, '</worksheet>');
+        fclose($this->sheetFilePointer);
+    }
+}

src/Spout/Writer/XLSX/Sheet.php

@@ -0,0 +1,55 @@
+<?php
+
+namespace Box\Spout\Writer\XLSX;
+
+/**
+ * Class Sheet
+ * Represents a worksheet within a XLSX file
+ *
+ * @package Box\Spout\Writer\XLSX
+ */
+class Sheet
+{
+    const DEFAULT_SHEET_NAME_PREFIX = 'Sheet';
+
+    /** @var int Index of the sheet, based on order of creation (zero-based) */
+    protected $index;
+
+    /** @var string Name of the sheet */
+    protected $name;
+
+    /**
+     * @param int $sheetIndex Index of the sheet, based on order of creation (zero-based)
+     */
+    function __construct($sheetIndex)
+    {
+        $this->index = $sheetIndex;
+        $this->name = self::DEFAULT_SHEET_NAME_PREFIX . ($sheetIndex + 1);
+    }
+
+    /**
+     * @return int Index of the sheet, based on order of creation (zero-based)
+     */
+    public function getIndex()
+    {
+        return $this->index;
+    }
+
+    /**
+     * @return string Name of the sheet
+     */
+    public function getName()
+    {
+        return $this->name;
+    }
+
+    /**
+     * @param string $name Name of the sheet
+     * @return Sheet
+     */
+    public function setName($name)
+    {
+        $this->name = $name;
+        return $this;
+    }
+}

src/Spout/Writer/XLSX/Writer.php

@@ -0,0 +1,185 @@
+<?php
+
+namespace Box\Spout\Writer\XLSX;
+
+use Box\Spout\Writer\AbstractWriter;
+use Box\Spout\Writer\Exception\WriterNotOpenedException;
+use Box\Spout\Writer\XLSX\Internal\Workbook;
+
+/**
+ * Class Writer
+ * This class provides base support to write data to XLSX files
+ *
+ * @package Box\Spout\Writer\XLSX
+ */
+class Writer extends AbstractWriter
+{
+    /** @var string Content-Type value for the header */
+    protected static $headerContentType = 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet';
+
+    /** @var string Temporary folder where the files to create the XLSX will be stored */
+    protected $tempFolder;
+
+    /** @var bool Whether inline or shared strings should be used - inline string is more memory efficient */
+    protected $shouldUseInlineStrings = true;
+
+    /** @var bool Whether new sheets should be automatically created when the max rows limit per sheet is reached */
+    protected $shouldCreateNewSheetsAutomatically = true;
+
+    /** @var Internal\Workbook The workbook for the XLSX file */
+    protected $book;
+
+    /** @var int */
+    protected $highestRowIndex = 0;
+
+    /**
+     * @param string $tempFolder Temporary folder where the files to create the XLSX will be stored
+     * @return Writer
+     */
+    public function setTempFolder($tempFolder)
+    {
+        $this->tempFolder = $tempFolder;
+        return $this;
+    }
+
+    /**
+     * Use inline string to be more memory efficient. If set to false, it will use shared strings.
+     *
+     * @param bool $shouldUseInlineStrings Whether inline or shared strings should be used
+     * @return Writer
+     */
+    public function setShouldUseInlineStrings($shouldUseInlineStrings)
+    {
+        $this->shouldUseInlineStrings = $shouldUseInlineStrings;
+        return $this;
+    }
+
+    /**
+     * @param bool $shouldCreateNewSheetsAutomatically Whether new sheets should be automatically created when the max rows limit per sheet is reached
+     * @return Writer
+     */
+    public function setShouldCreateNewSheetsAutomatically($shouldCreateNewSheetsAutomatically)
+    {
+        $this->shouldCreateNewSheetsAutomatically = $shouldCreateNewSheetsAutomatically;
+        return $this;
+    }
+
+    /**
+     * Configures the write and sets the current sheet pointer to a new sheet.
+     *
+     * @return void
+     * @throws \Box\Spout\Common\Exception\IOException If unable to open the file for writing
+     */
+    protected function openWriter()
+    {
+        if (!$this->book) {
+            $tempFolder = ($this->tempFolder) ? : sys_get_temp_dir();
+            $this->book = new Workbook($tempFolder, $this->shouldUseInlineStrings, $this->shouldCreateNewSheetsAutomatically);
+            $this->book->addNewSheetAndMakeItCurrent();
+        }
+    }
+
+    /**
+     * Returns all the workbook's sheets
+     *
+     * @return Sheet[] All the workbook's sheets
+     * @throws \Box\Spout\Writer\Exception\WriterNotOpenedException If the writer has not been opened yet
+     */
+    public function getSheets()
+    {
+        $this->throwIfBookIsNotAvailable();
+
+        $externalSheets = [];
+        $worksheets = $this->book->getWorksheets();
+
+        /** @var Internal\Worksheet $worksheet */
+        foreach ($worksheets as $worksheet) {
+            $externalSheets[] = $worksheet->getExternalSheet();
+        }
+
+        return $externalSheets;
+    }
+
+    /**
+     * Creates a new sheet and make it the current sheet. The data will now be written to this sheet.
+     *
+     * @return Sheet The created sheet
+     * @throws \Box\Spout\Writer\Exception\WriterNotOpenedException If the writer has not been opened yet
+     */
+    public function addNewSheetAndMakeItCurrent()
+    {
+        $this->throwIfBookIsNotAvailable();
+        $worksheet = $this->book->addNewSheetAndMakeItCurrent();
+
+        return $worksheet->getExternalSheet();
+    }
+
+    /**
+     * Returns the current sheet
+     *
+     * @return Sheet The current sheet
+     * @throws \Box\Spout\Writer\Exception\WriterNotOpenedException If the writer has not been opened yet
+     */
+    public function getCurrentSheet()
+    {
+        $this->throwIfBookIsNotAvailable();
+        return $this->book->getCurrentWorksheet()->getExternalSheet();
+    }
+
+    /**
+     * Sets the given sheet as the current one. New data will be written to this sheet.
+     * The writing will resume where it stopped (i.e. data won't be truncated).
+     *
+     * @param Sheet $sheet The sheet to set as current
+     * @return void
+     * @throws \Box\Spout\Writer\Exception\WriterNotOpenedException If the writer has not been opened yet
+     * @throws \Box\Spout\Writer\Exception\SheetNotFoundException If the given sheet does not exist in the workbook
+     */
+    public function setCurrentSheet($sheet)
+    {
+        $this->throwIfBookIsNotAvailable();
+        $this->book->setCurrentSheet($sheet);
+    }
+
+    /**
+     * Checks if the book has been created. Throws an exception if not created yet.
+     *
+     * @return void
+     * @throws \Box\Spout\Writer\Exception\WriterNotOpenedException If the book is not created yet
+     */
+    protected function throwIfBookIsNotAvailable()
+    {
+        if (!$this->book) {
+            throw new WriterNotOpenedException('The writer must be opened before performing this action.');
+        }
+    }
+
+    /**
+     * Adds data to the currently opened writer.
+     * If shouldCreateNewSheetsAutomatically option is set to true, it will handle pagination
+     * with the creation of new worksheets if one worksheet has reached its maximum capicity.
+     *
+     * @param array $dataRow Array containing data to be written.
+     *          Example $dataRow = ['data1', 1234, null, '', 'data5'];
+     * @return void
+     * @throws \Box\Spout\Writer\Exception\WriterNotOpenedException If the book is not created yet
+     * @throws \Box\Spout\Common\Exception\IOException If unable to write data
+     */
+    protected function addRowToWriter(array $dataRow)
+    {
+        $this->throwIfBookIsNotAvailable();
+        $this->book->addRowToCurrentWorksheet($dataRow);
+    }
+
+    /**
+     * Closes the writer, preventing any additional writing.
+     *
+     * @return void
+     */
+    protected function closeWriter()
+    {
+        if ($this->book) {
+            $this->book->close($this->filePointer);
+        }
+    }
+}