Merge pull request #161 from garak/patch-1

support branch alias

README.md

@@ -2,7 +2,7 @@
 
 [![Latest Stable Version](https://poser.pugx.org/box/spout/v/stable)](https://packagist.org/packages/box/spout)
 [![Project Status](http://opensource.box.com/badges/active.svg)](http://opensource.box.com/badges)
-[![Build Status](https://travis-ci.org/box/spout.svg?branch=master)](http://travis-ci.org/box/spout)
+[![Build Status](https://travis-ci.org/box/spout.svg?branch=master)](https://travis-ci.org/box/spout)
 [![Code Coverage](https://scrutinizer-ci.com/g/box/spout/badges/coverage.png?b=master)](https://scrutinizer-ci.com/g/box/spout/?branch=master)
 [![Total Downloads](https://poser.pugx.org/box/spout/downloads)](https://packagist.org/packages/box/spout)
 [![License](https://poser.pugx.org/box/spout/license)](https://packagist.org/packages/box/spout)
@@ -98,6 +98,8 @@ For XLSX and ODS files, the number of rows per sheet is limited to 1,048,576. By
 
 ## Advanced usage
 
+If you are looking for  how to perform some common, more advanced tasks with Spout, please take a look at the [Wiki](https://github.com/box/spout/wiki). It contains code snippets, ready to be used.
+
 ### Configuring the CSV reader and writer
 
 It is possible to configure both the CSV reader and writer to specify the field separator as well as the field enclosure:
@@ -275,10 +277,12 @@ If you just want to check that everything is working as expected, executing the
 If you want to run performance tests, you will need to checkout the `perf-tests` branch. Multiple test suites can then be run, depending on the expected output:
 
 * `phpunit` - runs the whole test suite (unit + functional + performance tests)
-* `phpunit --testuite no-perf-tests` - only runs the unit and functional tests
-* `phpunit --testuite perf-tests` - only runs the performance tests
+* `phpunit --exclude-group perf-tests` - only runs the unit and functional tests
+* `phpunit --group perf-tests` - only runs the performance tests
 
-For information, the performance tests take about one hour to run (processing 2 million rows files is not a quick thing).
+For information, the performance tests take about 30 minutes to run (processing 1 million rows files is not a quick thing).
+
+> Performance tests status: [![Build Status](https://travis-ci.org/box/spout.svg?branch=perf-tests)](https://travis-ci.org/box/spout)
 
 
 ## Frequently Asked Questions

composer.json

@@ -29,5 +29,11 @@
         "psr-4": {
             "Box\\Spout\\": "src/Spout"
         }
+    },
+    "extra": {
+        "branch-alias": {
+            "dev-master": "2.4.x-dev"
         }
+    }
+
 }

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

@@ -12,6 +12,14 @@ use Box\Spout\Common\Exception\InvalidArgumentException;
  */
 class CellHelper
 {
+    // Using ord() is super slow... Using a pre-computed hash table instead.
+    private static $columnLetterToIndexMapping = [
+        'A' => 0, 'B' => 1, 'C' => 2, 'D' => 3, 'E' => 4, 'F' => 5, 'G' => 6,
+        'H' => 7, 'I' => 8, 'J' => 9, 'K' => 10, 'L' => 11, 'M' => 12, 'N' => 13,
+        'O' => 14, 'P' => 15, 'Q' => 16, 'R' => 17, 'S' => 18, 'T' => 19, 'U' => 20,
+        'V' => 21, 'W' => 22, 'X' => 23, 'Y' => 24, 'Z' => 25,
+    ];
+
     /**
      * Fills the missing indexes of an array with a given value.
      * For instance, $dataArray = []; $a[1] = 1; $a[3] = 3;
@@ -50,34 +58,31 @@ class CellHelper
         }
 
         $columnIndex = 0;
-        $capitalAAsciiValue = ord('A');
-        $capitalZAsciiValue = ord('Z');
-        $step = $capitalZAsciiValue - $capitalAAsciiValue + 1;
 
         // Remove row information
-        $column = preg_replace('/\d/', '', $cellIndex);
-        $columnLength = strlen($column);
+        $columnLetters = preg_replace('/\d/', '', $cellIndex);
 
-        /*
-         * This is how the following loop will process the data:
-         * A   => 0
-         * Z   => 25
-         * AA  => 26   : (26^(2-1) * (0+1)) + 0
-         * AB  => 27   : (26^(2-1) * (0+1)) + 1
-         * BC  => 54   : (26^(2-1) * (1+1)) + 2
-         * BCZ => 1455 : (26^(3-1) * (1+1)) + (26^(2-1) * (2+1)) + 25
-         */
-        foreach (str_split($column) as $single_cell_index)
-        {
-            $currentColumnIndex = ord($single_cell_index) - $capitalAAsciiValue;
+        // strlen() is super slow too... Using isset() is way faster and not too unreadable,
+        // since we checked before that there are between 1 and 3 letters.
+        $columnLength = isset($columnLetters[1]) ? (isset($columnLetters[2]) ? 3 : 2) : 1;
 
-            if ($columnLength === 1) {
-                $columnIndex += $currentColumnIndex;
-            } else {
-                $columnIndex += pow($step, ($columnLength - 1)) * ($currentColumnIndex + 1);
-            }
-
-            $columnLength--;
+        // Looping over the different letters of the column is slower than this method.
+        // Also, not using the pow() function because it's slooooow...
+        switch ($columnLength) {
+            case 1:
+                $columnIndex = (self::$columnLetterToIndexMapping[$columnLetters]);
+                break;
+            case 2:
+                $firstLetterIndex = (self::$columnLetterToIndexMapping[$columnLetters[0]] + 1) * 26;
+                $secondLetterIndex = self::$columnLetterToIndexMapping[$columnLetters[1]];
+                $columnIndex = $firstLetterIndex + $secondLetterIndex;
+                break;
+            case 3:
+                $firstLetterIndex = (self::$columnLetterToIndexMapping[$columnLetters[0]] + 1) * 676;
+                $secondLetterIndex = (self::$columnLetterToIndexMapping[$columnLetters[1]] + 1) * 26;
+                $thirdLetterIndex = self::$columnLetterToIndexMapping[$columnLetters[2]];
+                $columnIndex = $firstLetterIndex + $secondLetterIndex + $thirdLetterIndex;
+                break;
         }
 
         return $columnIndex;
@@ -86,12 +91,13 @@ class CellHelper
     /**
      * Returns whether a cell index is valid, in an Excel world.
      * To be valid, the cell index should start with capital letters and be followed by numbers.
+     * There can only be 3 letters, as there can only be 16,384 rows, which is equivalent to 'XFE'.
      *
      * @param string $cellIndex The Excel cell index ('A1', 'BC13', ...)
      * @return bool
      */
     protected static function isValidCellIndex($cellIndex)
     {
-        return (preg_match('/^[A-Z]+\d+$/', $cellIndex) === 1);
+        return (preg_match('/^[A-Z]{1,3}\d+$/', $cellIndex) === 1);
     }
 }

src/Spout/Reader/XLSX/Helper/CellValueFormatter.php

@@ -28,7 +28,6 @@ class CellValueFormatter
     const XML_ATTRIBUTE_STYLE_ID = 's';
 
     /** Constants used for date formatting */
-    const NUM_DAYS_FROM_JAN_1_1900_TO_JAN_1_1970 = 25569; // actually 25567 but accommodating for an Excel bug with some bisextile years
     const NUM_SECONDS_IN_ONE_DAY = 86400;
 
     /**
@@ -183,17 +182,26 @@ class CellValueFormatter
      */
     protected function formatExcelTimestampValue($nodeValue)
     {
-        $numDaysSince1970Jan1 = $nodeValue - self::NUM_DAYS_FROM_JAN_1_1900_TO_JAN_1_1970;
-
         // Fix for the erroneous leap year in Excel
-        if ($nodeValue < self::ERRONEOUS_EXCEL_LEAP_YEAR_DAY) {
-            $numDaysSince1970Jan1++;
+        if (ceil($nodeValue) > self::ERRONEOUS_EXCEL_LEAP_YEAR_DAY) {
+            --$nodeValue;
         }
 
-        $unixTimestamp = round($numDaysSince1970Jan1 * self::NUM_SECONDS_IN_ONE_DAY);
+        // The value 1.0 represents 1900-01-01. Numbers below 1.0 are not valid Excel dates.
+        if ($nodeValue < 1.0) {
+            return null;
+        }
+
+        // Do not use any unix timestamps for calculation to prevent
+        // issues with numbers exceeding 2^31.
+        $secondsRemainder = fmod($nodeValue, 1) * self::NUM_SECONDS_IN_ONE_DAY;
+        $secondsRemainder = round($secondsRemainder, 0);
 
         try {
-            $cellValue = (new \DateTime())->setTimestamp($unixTimestamp);
+            $cellValue = \DateTime::createFromFormat('|Y-m-d', '1899-12-31');
+            $cellValue->modify('+' . intval($nodeValue) . 'days');
+            $cellValue->modify('+' . $secondsRemainder . 'seconds');
+
             return $cellValue;
         } catch (\Exception $e) {
             return null;

src/Spout/Reader/XLSX/Helper/SharedStringsCaching/FileBasedStrategy.php

@@ -143,7 +143,9 @@ class FileBasedStrategy implements CachingStrategyInterface
         }
 
         $sharedString = null;
-        if (array_key_exists($indexInFile, $this->inMemoryTempFileContents)) {
+
+        // Using isset here because it is way faster than array_key_exists...
+        if (isset($this->inMemoryTempFileContents[$indexInFile])) {
             $escapedSharedString = $this->inMemoryTempFileContents[$indexInFile];
             $sharedString = $this->unescapeLineFeed($escapedSharedString);
         }

src/Spout/Reader/XLSX/Helper/StyleHelper.php

@@ -148,7 +148,8 @@ class StyleHelper
 
         // Default style (0) does not format numeric values as timestamps. Only custom styles do.
         // Also if the style ID does not exist in the styles.xml file, format as numeric value.
-        if ($styleId === self::DEFAULT_STYLE_ID || !array_key_exists($styleId, $stylesAttributes)) {
+        // Using isset here because it is way faster than array_key_exists...
+        if ($styleId === self::DEFAULT_STYLE_ID || !isset($stylesAttributes[$styleId])) {
             return false;
         }
 
@@ -193,7 +194,8 @@ class StyleHelper
     {
         $customNumberFormats = $this->getCustomNumberFormats();
 
-        if (!array_key_exists($numFmtId, $customNumberFormats)) {
+        // Using isset here because it is way faster than array_key_exists...
+        if (!isset($customNumberFormats[$numFmtId])) {
             return false;
         }
 

src/Spout/Reader/XLSX/SheetIterator.php

@@ -67,7 +67,8 @@ class SheetIterator implements IteratorInterface
      */
     public function next()
     {
-        if (array_key_exists($this->currentSheetIndex, $this->sheets)) {
+        // Using isset here because it is way faster than array_key_exists...
+        if (isset($this->sheets[$this->currentSheetIndex])) {
             $currentSheet = $this->sheets[$this->currentSheetIndex];
             $currentSheet->getRowIterator()->end();
 

src/Spout/Writer/Common/Helper/AbstractStyleHelper.php

@@ -56,7 +56,9 @@ abstract class AbstractStyleHelper
     protected function hasStyleAlreadyBeenRegistered($style)
     {
         $serializedStyle = $style->serialize();
-        return array_key_exists($serializedStyle, $this->serializedStyleToStyleIdMappingTable);
+
+        // Using isset here because it is way faster than array_key_exists...
+        return isset($this->serializedStyleToStyleIdMappingTable[$serializedStyle]);
     }
 
     /**

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

@@ -10,6 +10,9 @@ namespace Box\Spout\Writer\Common\Helper;
  */
 class CellHelper
 {
+    /** @var array Cache containing the mapping column index => cell index */
+    private static $columnIndexToCellIndexCache = [];
+
     /**
      * Returns the cell index (base 26) associated to the base 10 column index.
      * Excel uses A to Z letters for column indexing, where A is the 1st column,
@@ -21,6 +24,10 @@ class CellHelper
      */
     public static function getCellIndexFromColumnIndex($columnIndex)
     {
+        $originalColumnIndex = $columnIndex;
+
+        // Using isset here because it is way faster than array_key_exists...
+        if (!isset(self::$columnIndexToCellIndexCache[$originalColumnIndex])) {
             $cellIndex = '';
             $capitalAAsciiValue = ord('A');
 
@@ -30,9 +37,13 @@ class CellHelper
 
                 // substracting 1 because it's zero-based
                 $columnIndex = intval($columnIndex / 26) - 1;
+
             } while ($columnIndex >= 0);
 
-        return $cellIndex;
+            self::$columnIndexToCellIndexCache[$originalColumnIndex] = $cellIndex;
+        }
+
+        return self::$columnIndexToCellIndexCache[$originalColumnIndex];
     }
 
     /**

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

@@ -12,52 +12,142 @@ class ZipHelper
 {
     const ZIP_EXTENSION = '.zip';
 
+    /** Controls what to do when trying to add an existing file */
+    const EXISTING_FILES_SKIP = 'skip';
+    const EXISTING_FILES_OVERWRITE = 'overwrite';
+
+    /** @var string Path of the folder where the zip file will be created */
+    protected $tmpFolderPath;
+
+    /** @var \ZipArchive The ZipArchive instance */
+    protected $zip;
+
     /**
-     * Zips the root folder and streams the contents of the zip into the given stream
-     *
-     * @param string $folderPath Path to the folder to be zipped
-     * @param resource $streamPointer Pointer to the stream to copy the zip
-     * @return void
+     * @param string $tmpFolderPath Path of the temp folder where the zip file will be created
      */
-    public function zipFolderAndCopyToStream($folderPath, $streamPointer)
+    public function __construct($tmpFolderPath)
     {
-        $zipFilePath = $this->getZipFilePath($folderPath);
-        $this->zipFolder($folderPath, $zipFilePath);
-        $this->copyZipToStream($zipFilePath, $streamPointer);
+        $this->tmpFolderPath = $tmpFolderPath;
+    }
+
+    /**
+     * Returns the already created ZipArchive instance or
+     * creates one if none exists.
+     *
+     * @return \ZipArchive
+     */
+    protected function createOrGetZip()
+    {
+        if (!isset($this->zip)) {
+            $this->zip = new \ZipArchive();
+            $zipFilePath = $this->getZipFilePath();
+
+            $this->zip->open($zipFilePath, \ZipArchive::CREATE|\ZipArchive::OVERWRITE);
+        }
+
+        return $this->zip;
     }
 
     /**
-     * @param string $folderPathToZip Path to the folder to be zipped
      * @return string Path where the zip file of the given folder will be created
      */
-    public function getZipFilePath($folderPathToZip)
+    public function getZipFilePath()
     {
-        return $folderPathToZip . self::ZIP_EXTENSION;
+        return $this->tmpFolderPath . self::ZIP_EXTENSION;
     }
 
     /**
-     * Zips the given folder
+     * Adds the given file, located under the given root folder to the archive.
+     * The file will be compressed.
      *
-     * @param string $folderPath Path of the folder to be zipped
-     * @param string $destinationPath Path where the zip file will be created
+     * Example of use:
+     *   addFileToArchive('/tmp/xlsx/foo', 'bar/baz.xml');
+     *   => will add the file located at '/tmp/xlsx/foo/bar/baz.xml' in the archive, but only as 'bar/baz.xml'
+     *
+     * @param string $rootFolderPath Path of the root folder that will be ignored in the archive tree.
+     * @param string $localFilePath Path of the file to be added, under the root folder
+     * @param string|void $existingFileMode Controls what to do when trying to add an existing file
      * @return void
      */
-    public function zipFolder($folderPath, $destinationPath)
+    public function addFileToArchive($rootFolderPath, $localFilePath, $existingFileMode = self::EXISTING_FILES_OVERWRITE)
     {
-        $zip = new \ZipArchive();
-        if ($zip->open($destinationPath, \ZipArchive::CREATE)) {
-            $this->addFolderToZip($zip, $folderPath);
-            $zip->close();
+        $this->addFileToArchiveWithCompressionMethod(
+            $rootFolderPath,
+            $localFilePath,
+            $existingFileMode,
+            \ZipArchive::CM_DEFAULT
+        );
+    }
+
+    /**
+     * Adds the given file, located under the given root folder to the archive.
+     * The file will NOT be compressed.
+     *
+     * Example of use:
+     *   addUncompressedFileToArchive('/tmp/xlsx/foo', 'bar/baz.xml');
+     *   => will add the file located at '/tmp/xlsx/foo/bar/baz.xml' in the archive, but only as 'bar/baz.xml'
+     *
+     * @param string $rootFolderPath Path of the root folder that will be ignored in the archive tree.
+     * @param string $localFilePath Path of the file to be added, under the root folder
+     * @param string|void $existingFileMode Controls what to do when trying to add an existing file
+     * @return void
+     */
+    public function addUncompressedFileToArchive($rootFolderPath, $localFilePath, $existingFileMode = self::EXISTING_FILES_OVERWRITE)
+    {
+        $this->addFileToArchiveWithCompressionMethod(
+            $rootFolderPath,
+            $localFilePath,
+            $existingFileMode,
+            \ZipArchive::CM_STORE
+        );
+    }
+
+    /**
+     * Adds the given file, located under the given root folder to the archive.
+     * The file will NOT be compressed.
+     *
+     * Example of use:
+     *   addUncompressedFileToArchive('/tmp/xlsx/foo', 'bar/baz.xml');
+     *   => will add the file located at '/tmp/xlsx/foo/bar/baz.xml' in the archive, but only as 'bar/baz.xml'
+     *
+     * @param string $rootFolderPath Path of the root folder that will be ignored in the archive tree.
+     * @param string $localFilePath Path of the file to be added, under the root folder
+     * @param string $existingFileMode Controls what to do when trying to add an existing file
+     * @param int $compressionMethod The compression method
+     * @return void
+     */
+    protected function addFileToArchiveWithCompressionMethod($rootFolderPath, $localFilePath, $existingFileMode, $compressionMethod)
+    {
+        $zip = $this->createOrGetZip();
+
+        if (!$this->shouldSkipFile($zip, $localFilePath, $existingFileMode)) {
+            $normalizedFullFilePath = $this->getNormalizedRealPath($rootFolderPath . '/' . $localFilePath);
+            $zip->addFile($normalizedFullFilePath, $localFilePath);
+
+            if (self::canChooseCompressionMethod()) {
+                $zip->setCompressionName($localFilePath, $compressionMethod);
+            }
         }
     }
 
     /**
-     * @param \ZipArchive $zip
-     * @param string $folderPath Path of the folder to add to the zip
+     * @return bool Whether it is possible to choose the desired compression method to be used
+     */
+    public static function canChooseCompressionMethod()
+    {
+        // setCompressionName() is a PHP7+ method...
+        return (method_exists(new \ZipArchive(), 'setCompressionName'));
+    }
+
+    /**
+     * @param string $folderPath Path to the folder to be zipped
+     * @param string|void $existingFileMode Controls what to do when trying to add an existing file
      * @return void
      */
-    protected function addFolderToZip($zip, $folderPath)
+    public function addFolderToArchive($folderPath, $existingFileMode = self::EXISTING_FILES_OVERWRITE)
     {
+        $zip = $this->createOrGetZip();
+
         $folderRealPath = $this->getNormalizedRealPath($folderPath) . '/';
         $itemIterator = new \RecursiveIteratorIterator(new \RecursiveDirectoryIterator($folderPath, \RecursiveDirectoryIterator::SKIP_DOTS), \RecursiveIteratorIterator::SELF_FIRST);
 
@@ -65,14 +155,26 @@ class ZipHelper
             $itemRealPath = $this->getNormalizedRealPath($itemInfo->getPathname());
             $itemLocalPath = str_replace($folderRealPath, '', $itemRealPath);
 
-            if ($itemInfo->isFile()) {
+            if ($itemInfo->isFile() && !$this->shouldSkipFile($zip, $itemLocalPath, $existingFileMode)) {
                 $zip->addFile($itemRealPath, $itemLocalPath);
-            } else if ($itemInfo->isDir()) {
-                $zip->addEmptyDir($itemLocalPath);
             }
         }
     }
 
+    /**
+     * @param \ZipArchive $zip
+     * @param string $itemLocalPath
+     * @param string $existingFileMode
+     * @return bool Whether the file should be added to the archive or skipped
+     */
+    protected function shouldSkipFile($zip, $itemLocalPath, $existingFileMode)
+    {
+        // Skip files if:
+        //   - EXISTING_FILES_SKIP mode chosen
+        //   - File already exists in the archive
+        return ($existingFileMode === self::EXISTING_FILES_SKIP && $zip->locateName($itemLocalPath) !== false);
+    }
+
     /**
      * Returns canonicalized absolute pathname, containing only forward slashes.
      *
@@ -85,16 +187,30 @@ class ZipHelper
         return str_replace(DIRECTORY_SEPARATOR, '/', $realPath);
     }
 
+    /**
+     * Closes the archive and copies it into the given stream
+     *
+     * @param resource $streamPointer Pointer to the stream to copy the zip
+     * @return void
+     */
+    public function closeArchiveAndCopyToStream($streamPointer)
+    {
+        $zip = $this->createOrGetZip();
+        $zip->close();
+        unset($this->zip);
+
+        $this->copyZipToStream($streamPointer);
+    }
+
     /**
      * Streams the contents of the zip file into the given stream
      *
-     * @param string $zipFilePath Path to the zip file
      * @param resource $pointer Pointer to the stream to copy the zip
      * @return void
      */
-    protected function copyZipToStream($zipFilePath, $pointer)
+    protected function copyZipToStream($pointer)
     {
-        $zipFilePointer = fopen($zipFilePath, 'r');
+        $zipFilePointer = fopen($this->getZipFilePath(), 'r');
         stream_copy_to_stream($zipFilePointer, $pointer);
         fclose($zipFilePointer);
     }

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

@@ -103,14 +103,12 @@ class FileSystemHelper extends \Box\Spout\Common\Helper\FileSystemHelper
     protected function createManifestFile()
     {
         $manifestXmlFileContents = <<<EOD
-<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
-<manifest:manifest xmlns:manifest="urn:oasis:names:tc:opendocument:xmlns:manifest:1.0">
+<?xml version="1.0" encoding="UTF-8"?>
+<manifest:manifest xmlns:manifest="urn:oasis:names:tc:opendocument:xmlns:manifest:1.0" manifest:version="1.2">
     <manifest:file-entry manifest:full-path="/" manifest:media-type="application/vnd.oasis.opendocument.spreadsheet"/>
     <manifest:file-entry manifest:full-path="styles.xml" manifest:media-type="text/xml"/>
     <manifest:file-entry manifest:full-path="content.xml" manifest:media-type="text/xml"/>
     <manifest:file-entry manifest:full-path="meta.xml" manifest:media-type="text/xml"/>
-    <manifest:file-entry manifest:full-path="mimetype" manifest:media-type="text/plain"/>
-    <manifest:file-entry manifest:full-path="META-INF/manifest.xml" manifest:media-type="text/xml"/>
 </manifest:manifest>
 EOD;
 
@@ -265,10 +263,17 @@ EOD;
      */
     public function zipRootFolderAndCopyToStream($streamPointer)
     {
-        $zipHelper = new ZipHelper();
-        $zipHelper->zipFolderAndCopyToStream($this->rootFolder, $streamPointer);
+        $zipHelper = new ZipHelper($this->rootFolder);
+
+        // In order to have the file's mime type detected properly, files need to be added
+        // to the zip file in a particular order.
+        // @see http://www.jejik.com/articles/2010/03/how_to_correctly_create_odf_documents_using_zip/
+        $zipHelper->addUncompressedFileToArchive($this->rootFolder, self::MIMETYPE_FILE_NAME);
+
+        $zipHelper->addFolderToArchive($this->rootFolder, ZipHelper::EXISTING_FILES_SKIP);
+        $zipHelper->closeArchiveAndCopyToStream($streamPointer);
 
         // once the zip is copied, remove it
-        $this->deleteFile($zipHelper->getZipFilePath($this->rootFolder));
+        $this->deleteFile($zipHelper->getZipFilePath());
     }
 }

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

@@ -146,7 +146,8 @@ class Worksheet implements WorksheetInterface
         for ($i = 0; $i < $cellsCount; $i++) {
             $currentCellValue = $dataRow[$currentCellIndex];
 
-            if (!array_key_exists($nextCellIndex, $dataRow) || $currentCellValue !== $dataRow[$nextCellIndex]) {
+            // Using isset here because it is way faster than array_key_exists...
+            if (!isset($dataRow[$nextCellIndex]) || $currentCellValue !== $dataRow[$nextCellIndex]) {
                 $numTimesValueRepeated = ($nextCellIndex - $currentCellIndex);
                 $data .= $this->getCellContent($currentCellValue, $styleIndex, $numTimesValueRepeated);
 

src/Spout/Writer/Style/Style.php

@@ -293,7 +293,7 @@ class Style
         if (!$this->hasSetFontSize && $baseStyle->getFontSize() !== self::DEFAULT_FONT_SIZE) {
             $mergedStyle->setFontSize($baseStyle->getFontSize());
         }
-        if (!$this->hasSetFontSize && $baseStyle->getFontColor() !== self::DEFAULT_FONT_COLOR) {
+        if (!$this->hasSetFontColor && $baseStyle->getFontColor() !== self::DEFAULT_FONT_COLOR) {
             $mergedStyle->setFontColor($baseStyle->getFontColor());
         }
         if (!$this->hasSetFontName && $baseStyle->getFontName() !== self::DEFAULT_FONT_NAME) {

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

@@ -353,10 +353,19 @@ EOD;
      */
     public function zipRootFolderAndCopyToStream($streamPointer)
     {
-        $zipHelper = new ZipHelper();
-        $zipHelper->zipFolderAndCopyToStream($this->rootFolder, $streamPointer);
+        $zipHelper = new ZipHelper($this->rootFolder);
+
+        // In order to have the file's mime type detected properly, files need to be added
+        // to the zip file in a particular order.
+        // "[Content_Types].xml" then at least 2 files located in "xl" folder should be zipped first.
+        $zipHelper->addFileToArchive($this->rootFolder, self::CONTENT_TYPES_XML_FILE_NAME);
+        $zipHelper->addFileToArchive($this->rootFolder, self::XL_FOLDER_NAME . '/' . self::WORKBOOK_XML_FILE_NAME);
+        $zipHelper->addFileToArchive($this->rootFolder, self::XL_FOLDER_NAME . '/' . self::STYLES_XML_FILE_NAME);
+
+        $zipHelper->addFolderToArchive($this->rootFolder, ZipHelper::EXISTING_FILES_SKIP);
+        $zipHelper->closeArchiveAndCopyToStream($streamPointer);
 
         // once the zip is copied, remove it
-        $this->deleteFile($zipHelper->getZipFilePath($this->rootFolder));
+        $this->deleteFile($zipHelper->getZipFilePath());
     }
 }

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

@@ -131,36 +131,38 @@ EOD;
         $rowIndex = $this->lastWrittenRowIndex + 1;
         $numCells = count($dataRow);
 
-        $data = '<row r="' . $rowIndex . '" spans="1:' . $numCells . '">';
+        $rowXML = '<row r="' . $rowIndex . '" spans="1:' . $numCells . '">';
 
         foreach($dataRow as $cellValue) {
             $columnIndex = CellHelper::getCellIndexFromColumnIndex($cellNumber);
-            $data .= '<c r="' . $columnIndex . $rowIndex . '"';
-            $data .= ' s="' . $style->getId() . '"';
+            $cellXML = '<c r="' . $columnIndex . $rowIndex . '"';
+            $cellXML .= ' s="' . $style->getId() . '"';
 
             if (CellHelper::isNonEmptyString($cellValue)) {
                 if ($this->shouldUseInlineStrings) {
-                    $data .= ' t="inlineStr"><is><t>' . $this->stringsEscaper->escape($cellValue) . '</t></is></c>';
+                    $cellXML .= ' t="inlineStr"><is><t>' . $this->stringsEscaper->escape($cellValue) . '</t></is></c>';
                 } else {
                     $sharedStringId = $this->sharedStringsHelper->writeString($cellValue);
-                    $data .= ' t="s"><v>' . $sharedStringId . '</v></c>';
+                    $cellXML .= ' t="s"><v>' . $sharedStringId . '</v></c>';
                 }
             } else if (CellHelper::isBoolean($cellValue)) {
-                $data .= ' t="b"><v>' . $cellValue . '</v></c>';
+                $cellXML .= ' t="b"><v>' . $cellValue . '</v></c>';
             } else if (CellHelper::isNumeric($cellValue)) {
-                $data .= '><v>' . $cellValue . '</v></c>';
+                $cellXML .= '><v>' . $cellValue . '</v></c>';
             } else if (empty($cellValue)) {
-                $data .= '/>';
+                // don't write empty cells (not appending to $cellXML is the right behavior!)
+                $cellXML = '';
             } else {
                 throw new InvalidArgumentException('Trying to add a value with an unsupported type: ' . gettype($cellValue));
             }
 
+            $rowXML .= $cellXML;
             $cellNumber++;
         }
 
-        $data .= '</row>';
+        $rowXML .= '</row>';
 
-        $wasWriteSuccessful = fwrite($this->sheetFilePointer, $data);
+        $wasWriteSuccessful = fwrite($this->sheetFilePointer, $rowXML);
         if ($wasWriteSuccessful === false) {
             throw new IOException("Unable to write data in {$this->worksheetFilePath}");
         }

tests/Spout/Reader/XLSX/Helper/CellValueFormatterTest.php

@@ -0,0 +1,80 @@
+<?php
+
+namespace Box\Spout\Reader\XLSX\Helper;
+
+/**
+ * Class CellValueFormatterTest
+ *
+ * @package Box\Spout\Reader\XLSX\Helper
+ */
+class CellValueFormatterTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * @return array
+     */
+    public function dataProviderForExcelDateTest()
+    {
+        return [
+            [ CellValueFormatter::CELL_TYPE_NUMERIC, 42429, '2016-02-29 00:00:00' ],
+            [ CellValueFormatter::CELL_TYPE_NUMERIC, '146098', '2299-12-31 00:00:00' ],
+            [ CellValueFormatter::CELL_TYPE_NUMERIC, -700, null ],
+            [ CellValueFormatter::CELL_TYPE_NUMERIC, 0, null ],
+            [ CellValueFormatter::CELL_TYPE_NUMERIC, 0.5, null ],
+            [ CellValueFormatter::CELL_TYPE_NUMERIC, 1, '1900-01-01 00:00:00' ],
+            [ CellValueFormatter::CELL_TYPE_NUMERIC, 59.999988425926, '1900-02-28 23:59:59' ],
+            [ CellValueFormatter::CELL_TYPE_NUMERIC, 60.458333333333, '1900-02-28 11:00:00' ],
+        ];
+    }
+
+    /**
+     * @dataProvider dataProviderForExcelDateTest
+     *
+     * @return void
+     */
+    public function testExcelDate($cellType, $nodeValue, $expectedDateAsString)
+    {
+        $nodeListMock = $this->getMockBuilder('DOMNodeList')->disableOriginalConstructor()->getMock();
+
+        $nodeListMock
+            ->expects($this->atLeastOnce())
+            ->method('item')
+            ->with(0)
+            ->will($this->returnValue((object)[ 'nodeValue' => $nodeValue ]));
+
+        $nodeMock = $this->getMockBuilder('DOMElement')->disableOriginalConstructor()->getMock();
+
+        $nodeMock
+            ->expects($this->atLeastOnce())
+            ->method('getAttribute')
+            ->will($this->returnValueMap([
+                [ CellValueFormatter::XML_ATTRIBUTE_TYPE, $cellType ],
+                [ CellValueFormatter::XML_ATTRIBUTE_STYLE_ID, 123 ],
+            ]));
+
+        $nodeMock
+            ->expects($this->atLeastOnce())
+            ->method('getElementsByTagName')
+            ->with(CellValueFormatter::XML_NODE_VALUE)
+            ->will($this->returnValue($nodeListMock));
+
+        $styleHelperMock = $this->getMockBuilder(__NAMESPACE__ . '\StyleHelper')->disableOriginalConstructor()->getMock();
+
+        $styleHelperMock
+            ->expects($this->once())
+            ->method('shouldFormatNumericValueAsDate')
+            ->with(123)
+            ->will($this->returnValue(true));
+
+        $instance = new CellValueFormatter(null, $styleHelperMock);
+
+        $result = $instance->extractAndFormatNodeValue($nodeMock);
+
+        if ($expectedDateAsString === null) {
+            $this->assertNull($result);
+        } else {
+            $this->assertInstanceOf('DateTime', $result);
+            $this->assertSame($expectedDateAsString, $result->format('Y-m-d H:i:s'));
+        }
+    }
+
+}

tests/Spout/Writer/ODS/WriterTest.php

@@ -5,6 +5,7 @@ namespace Box\Spout\Writer\ODS;
 use Box\Spout\Common\Type;
 use Box\Spout\Reader\Wrapper\XMLReader;
 use Box\Spout\TestUsingResource;
+use Box\Spout\Writer\Common\Helper\ZipHelper;
 use Box\Spout\Writer\WriterFactory;
 
 /**
@@ -368,6 +369,30 @@ class WriterTest extends \PHPUnit_Framework_TestCase
         $this->assertValueWasWrittenToSheet($fileName, 1, 'a dream');
     }
 
+    /**
+     * @return void
+     */
+    public function testGeneratedFileShouldHaveTheCorrectMimeType()
+    {
+        // Only PHP7+ gives the correct mime type since it requires adding
+        // uncompressed files to the final archive (which support was added in PHP7)
+        if (!ZipHelper::canChooseCompressionMethod()) {
+            $this->markTestSkipped(
+                'The PHP version used does not support setting the compression method of archived files,
+                resulting in the mime type to be detected incorrectly.'
+            );
+        }
+
+        $fileName = 'test_mime_type.ods';
+        $resourcePath = $this->getGeneratedResourcePath($fileName);
+        $dataRow = ['foo'];
+
+        $this->writeToODSFile([$dataRow], $fileName);
+
+        $finfo = new \finfo(FILEINFO_MIME_TYPE);
+        $this->assertEquals('application/vnd.oasis.opendocument.spreadsheet', $finfo->file($resourcePath));
+    }
+
     /**
      * @param array $allRows
      * @param string $fileName

tests/Spout/Writer/XLSX/WriterTest.php

@@ -385,6 +385,21 @@ class WriterTest extends \PHPUnit_Framework_TestCase
         $this->assertInlineDataWasWrittenToSheet($fileName, 1, 'control's _x0015_ "character"');
     }
 
+    /**
+     * @return void
+     */
+    public function testGeneratedFileShouldHaveTheCorrectMimeType()
+    {
+        $fileName = 'test_mime_type.xlsx';
+        $resourcePath = $this->getGeneratedResourcePath($fileName);
+        $dataRows = [['foo']];
+
+        $this->writeToXLSXFile($dataRows, $fileName);
+
+        $finfo = new \finfo(FILEINFO_MIME_TYPE);
+        $this->assertEquals('application/vnd.openxmlformats-officedocument.spreadsheetml.sheet', $finfo->file($resourcePath));
+    }
+
     /**
      * @param array $allRows
      * @param string $fileName