Merge pull request #67 from box/caching_strategies

Caching strategies

.travis.yml

@@ -8,7 +8,11 @@ php:
   - hhvm
 
 install:
-  - composer self-update
-  - composer install --prefer-source
+  - composer install --no-interaction
 
-script: phpunit
+script:
+  - mkdir -p build/logs
+  - php vendor/bin/phpunit --coverage-clover build/logs/clover.xml
+
+after_script:
+  - php vendor/bin/coveralls -v

README.md

@@ -3,7 +3,9 @@
 [![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.png?branch=master)](http://travis-ci.org/box/spout)
-[![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)
+[![Coverage Status](https://coveralls.io/repos/box/spout/badge.svg?branch=master)](https://coveralls.io/r/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)
 
 Spout is a PHP library to read and write CSV and XLSX files, in a fast and scalable way.
 Contrary to other file readers or writers, it is capable of processing very large files while keeping the memory usage really low (less than 10MB).

composer.json

@@ -2,7 +2,6 @@
     "name": "box/spout",
     "description": "PHP Library to read and write CSV and XLSX files, in a fast and scalable way",
     "type": "library",
-    "version": "1.0.9",
     "keywords": ["php","read","write","csv","xlsx","excel","spreadsheet","scale","memory","stream","ooxml"],
     "license": "Apache-2.0",
     "homepage": "https://www.github.com/box/spout",
@@ -19,7 +18,8 @@
         "ext-simplexml": "*"
     },
     "require-dev": {
-        "phpunit/phpunit": ">=3.7"
+        "phpunit/phpunit": ">=3.7",
+        "satooshi/php-coveralls": "^0.6.1"
     },
     "autoload": {
         "psr-4": {

phpunit.xml

@@ -14,10 +14,6 @@
         </testsuite>
     </testsuites>
 
-    <logging>
-        <log type="coverage-html" target="tests/coverage/"/>
-    </logging>
-
     <filter>
         <whitelist>
             <directory suffix=".php">src/</directory>

src/Spout/Common/Helper/FileSystemHelper.php

@@ -36,7 +36,7 @@ class FileSystemHelper
     {
         $this->throwIfOperationNotInBaseFolder($parentFolderPath);
 
-        $folderPath = $parentFolderPath . DIRECTORY_SEPARATOR . $folderName;
+        $folderPath = $parentFolderPath . '/' . $folderName;
 
         $wasCreationSuccessful = mkdir($folderPath, 0777, true);
         if (!$wasCreationSuccessful) {
@@ -60,7 +60,7 @@ class FileSystemHelper
     {
         $this->throwIfOperationNotInBaseFolder($parentFolderPath);
 
-        $filePath = $parentFolderPath . DIRECTORY_SEPARATOR . $fileName;
+        $filePath = $parentFolderPath . '/' . $fileName;
 
         $wasCreationSuccessful = file_put_contents($filePath, $fileContents);
         if (!$wasCreationSuccessful) {

src/Spout/Common/Helper/GlobalFunctionsHelper.php

@@ -106,6 +106,19 @@ class GlobalFunctionsHelper
         return fputcsv($handle, $fields, $delimiter, $enclosure);
     }
 
+    /**
+     * Wrapper around global function fwrite()
+     * @see fwrite()
+     *
+     * @param resource $handle
+     * @param string $string
+     * @return int
+     */
+    public function fwrite($handle, $string)
+    {
+        return fwrite($handle, $string);
+    }
+
     /**
      * Wrapper around global function fclose()
      * @see fclose()

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

@@ -0,0 +1,154 @@
+<?php
+
+namespace Box\Spout\Reader\Helper\XLSX\SharedStringsCaching;
+
+/**
+ * Class CachingStrategyFactory
+ *
+ * @package Box\Spout\Reader\Helper\XLSX\SharedStringsCaching
+ */
+class CachingStrategyFactory
+{
+    /**
+     * The memory amount needed to store a string was obtained empirically from this data:
+     *
+     *        ------------------------------------
+     *        | Number of chars⁺ | Memory needed |
+     *        ------------------------------------
+     *        |           3,000  |         1 MB  |
+     *        |          15,000  |         2 MB  |
+     *        |          30,000  |         5 MB  |
+     *        |          75,000  |        11 MB  |
+     *        |         150,000  |        21 MB  |
+     *        |         300,000  |        43 MB  |
+     *        |         750,000  |       105 MB  |
+     *        |       1,500,000  |       210 MB  |
+     *        |       2,250,000  |       315 MB  |
+     *        |       3,000,000  |       420 MB  |
+     *        |       4,500,000  |       630 MB  |
+     *        ------------------------------------
+     *
+     *        ⁺ All characters were 1 byte long
+     *
+     * This gives a linear graph where each 1-byte character requires about 150 bytes to be stored.
+     * Given that some characters can take up to 4 bytes, we need 600 bytes per character to be safe.
+     * Also, there is on average about 20 characters per cell (this is entirely empirical data...).
+     *
+     * This means that in order to store one shared string in memory, the memory amount needed is:
+     *   => 20 * 600 ≈ 12KB
+     */
+    const AMOUNT_MEMORY_NEEDED_PER_STRING_IN_KB = 12;
+
+    /**
+     * To avoid running out of memory when extracting a huge number of shared strings, they can be saved to temporary files
+     * instead of in memory. Then, when accessing a string, the corresponding file contents will be loaded in memory
+     * and the string will be quickly retrieved.
+     * The performance bottleneck is not when creating these temporary files, but rather when loading their content.
+     * Because the contents of the last loaded file stays in memory until another file needs to be loaded, it works
+     * best when the indexes of the shared strings are sorted in the sheet data.
+     * 10,000 was chosen because it creates small files that are fast to be loaded in memory.
+     */
+    const MAX_NUM_STRINGS_PER_TEMP_FILE = 10000;
+
+    /** @var CachingStrategyFactory|null Singleton instance */
+    protected static $instance = null;
+
+    /**
+     * Private constructor for singleton
+     */
+    private function __construct()
+    {
+    }
+
+    /**
+     * Returns the singleton instance of the factory
+     *
+     * @return CachingStrategyFactory
+     */
+    public static function getInstance()
+    {
+        if (self::$instance === null) {
+            self::$instance = new CachingStrategyFactory();
+        }
+
+        return self::$instance;
+    }
+
+    /**
+     * Returns the best caching strategy, given the number of unique shared strings
+     * and the amount of memory available.
+     *
+     * @param int $sharedStringsUniqueCount Number of unique shared strings
+     * @param string|void $tempFolder Temporary folder where the temporary files to store shared strings will be stored
+     * @return CachingStrategyInterface The best caching strategy
+     */
+    public function getBestCachingStrategy($sharedStringsUniqueCount, $tempFolder = null)
+    {
+        if ($this->isInMemoryStrategyUsageSafe($sharedStringsUniqueCount)) {
+            return new InMemoryStrategy($sharedStringsUniqueCount);
+        } else {
+            return new FileBasedStrategy($tempFolder, self::MAX_NUM_STRINGS_PER_TEMP_FILE);
+        }
+    }
+
+    /**
+     * Returns whether it is safe to use in-memory caching, given the number of unique shared strings
+     * and the amount of memory available.
+     *
+     * @param int $sharedStringsUniqueCount Number of unique shared strings
+     * @return bool
+     */
+    protected function isInMemoryStrategyUsageSafe($sharedStringsUniqueCount)
+    {
+        $memoryAvailable = $this->getMemoryLimitInKB();
+
+        if ($memoryAvailable === -1) {
+            // if cannot get memory limit or if memory limit set as unlimited, don't trust and play safe
+            return ($sharedStringsUniqueCount < self::MAX_NUM_STRINGS_PER_TEMP_FILE);
+        } else {
+            $memoryNeeded = $sharedStringsUniqueCount * self::AMOUNT_MEMORY_NEEDED_PER_STRING_IN_KB;
+            return ($memoryAvailable > $memoryNeeded);
+        }
+    }
+
+    /**
+     * Returns the PHP "memory_limit" in Kilobytes
+     *
+     * @return float
+     */
+    protected function getMemoryLimitInKB()
+    {
+        $memoryLimitFormatted = $this->getMemoryLimitFromIni();
+        $memoryLimitFormatted = strtolower(trim($memoryLimitFormatted));
+
+        // No memory limit
+        if ($memoryLimitFormatted === '-1') {
+            return -1;
+        }
+
+        if (preg_match('/(\d+)([bkmgt])b?/', $memoryLimitFormatted, $matches)) {
+            $amount = intval($matches[1]);
+            $unit = $matches[2];
+
+            switch ($unit) {
+                case 'b': return ($amount / 1024);
+                case 'k': return $amount;
+                case 'm': return ($amount * 1024);
+                case 'g': return ($amount * 1024 * 1024);
+                case 't': return ($amount * 1024 * 1024 * 1024);
+            }
+        }
+
+        return -1;
+    }
+
+    /**
+     * Returns the formatted "memory_limit" value
+     *
+     * @return string
+     */
+    protected function getMemoryLimitFromIni()
+    {
+        return ini_get('memory_limit');
+    }
+}

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

@@ -0,0 +1,44 @@
+<?php
+
+namespace Box\Spout\Reader\Helper\XLSX\SharedStringsCaching;
+
+/**
+ * Interface CachingStrategyInterface
+ *
+ * @package Box\Spout\Reader\Helper\XLSX\SharedStringsCaching
+ */
+interface CachingStrategyInterface
+{
+    /**
+     * Adds the given string to the cache.
+     *
+     * @param string $sharedString The string to be added to the cache
+     * @param int $sharedStringIndex Index of the shared string in the sharedStrings.xml file
+     * @return void
+     */
+    public function addStringForIndex($sharedString, $sharedStringIndex);
+
+    /**
+     * Closes the cache after the last shared string was added.
+     * This prevents any additional string from being added to the cache.
+     *
+     * @return void
+     */
+    public function closeCache();
+
+    /**
+     * Returns the string located at the given index from the cache.
+     *
+     * @param int $sharedStringIndex Index of the shared string in the sharedStrings.xml file
+     * @return string The shared string at the given index
+     * @throws \Box\Spout\Reader\Exception\SharedStringNotFoundException If no shared string found for the given index
+     */
+    public function getStringAtIndex($sharedStringIndex);
+
+    /**
+     * Destroys the cache, freeing memory and removing any created artifacts
+     *
+     * @return void
+     */
+    public function clearCache();
+}

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

@@ -0,0 +1,188 @@
+<?php
+
+namespace Box\Spout\Reader\Helper\XLSX\SharedStringsCaching;
+
+use Box\Spout\Common\Helper\FileSystemHelper;
+use Box\Spout\Common\Helper\GlobalFunctionsHelper;
+use Box\Spout\Reader\Exception\SharedStringNotFoundException;
+
+/**
+ * Class FileBasedStrategy
+ *
+ * This class implements the file-based caching strategy for shared strings.
+ * Shared strings are stored in small files (with a max number of strings per file).
+ * This strategy is slower than an in-memory strategy but is used to avoid out of memory crashes.
+ *
+ * @package Box\Spout\Reader\Helper\XLSX\SharedStringsCaching
+ */
+class FileBasedStrategy implements CachingStrategyInterface
+{
+    /** Value to use to escape the line feed character ("\n") */
+    const ESCAPED_LINE_FEED_CHARACTER = '_x000A_';
+
+    /** @var \Box\Spout\Common\Helper\GlobalFunctionsHelper Helper to work with global functions */
+    protected $globalFunctionsHelper;
+
+    /** @var \Box\Spout\Common\Helper\FileSystemHelper Helper to perform file system operations */
+    protected $fileSystemHelper;
+
+    /**
+     * @var int Maximum number of strings that can be stored in one temp file
+     * @see CachingStrategyFactory::MAX_NUM_STRINGS_PER_TEMP_FILE
+     */
+    protected $maxNumStringsPerTempFile;
+
+    /** @var resource Pointer to the last temp file a shared string was written to */
+    protected $tempFilePointer;
+
+    /**
+     * @var string Path of the temporary file whose contents is currently stored in memory
+     * @see CachingStrategyFactory::MAX_NUM_STRINGS_PER_TEMP_FILE
+     */
+    protected $inMemoryTempFilePath;
+
+    /**
+     * @var string Contents of the temporary file that was last read
+     * @see CachingStrategyFactory::MAX_NUM_STRINGS_PER_TEMP_FILE
+     */
+    protected $inMemoryTempFileContents;
+
+    /**
+     * @param string|null $tempFolder Temporary folder where the temporary files to store shared strings will be stored
+     * @param int $maxNumStringsPerTempFile Maximum number of strings that can be stored in one temp file
+     */
+    public function __construct($tempFolder, $maxNumStringsPerTempFile)
+    {
+        $rootTempFolder = ($tempFolder) ?: sys_get_temp_dir();
+        $this->fileSystemHelper = new FileSystemHelper($rootTempFolder);
+        $this->tempFolder = $this->fileSystemHelper->createFolder($rootTempFolder, uniqid('sharedstrings'));
+
+        $this->maxNumStringsPerTempFile = $maxNumStringsPerTempFile;
+
+        $this->globalFunctionsHelper = new GlobalFunctionsHelper();
+        $this->tempFilePointer = null;
+    }
+
+    /**
+     * Adds the given string to the cache.
+     *
+     * @param string $sharedString The string to be added to the cache
+     * @param int $sharedStringIndex Index of the shared string in the sharedStrings.xml file
+     * @return void
+     */
+    public function addStringForIndex($sharedString, $sharedStringIndex)
+    {
+        $tempFilePath = $this->getSharedStringTempFilePath($sharedStringIndex);
+
+        if (!$this->globalFunctionsHelper->file_exists($tempFilePath)) {
+            if ($this->tempFilePointer) {
+                $this->globalFunctionsHelper->fclose($this->tempFilePointer);
+            }
+            $this->tempFilePointer = $this->globalFunctionsHelper->fopen($tempFilePath, 'w');
+        }
+
+        // The shared string retrieval logic expects each cell data to be on one line only
+        // Encoding the line feed character allows to preserve this assumption
+        $lineFeedEncodedSharedString = $this->escapeLineFeed($sharedString);
+
+        $this->globalFunctionsHelper->fwrite($this->tempFilePointer, $lineFeedEncodedSharedString . PHP_EOL);
+    }
+
+    /**
+     * Returns the path for the temp file that should contain the string for the given index
+     *
+     * @param int $sharedStringIndex Index of the shared string in the sharedStrings.xml file
+     * @return string The temp file path for the given index
+     */
+    protected function getSharedStringTempFilePath($sharedStringIndex)
+    {
+        $numTempFile = intval($sharedStringIndex / $this->maxNumStringsPerTempFile);
+        return $this->tempFolder . '/sharedstrings' . $numTempFile;
+    }
+
+    /**
+     * Closes the cache after the last shared string was added.
+     * This prevents any additional string from being added to the cache.
+     *
+     * @return void
+     */
+    public function closeCache()
+    {
+        // close pointer to the last temp file that was written
+        if ($this->tempFilePointer) {
+            $this->globalFunctionsHelper->fclose($this->tempFilePointer);
+        }
+    }
+
+
+    /**
+     * Returns the string located at the given index from the cache.
+     *
+     * @param int $sharedStringIndex Index of the shared string in the sharedStrings.xml file
+     * @return string The shared string at the given index
+     * @throws \Box\Spout\Reader\Exception\SharedStringNotFoundException If no shared string found for the given index
+     */
+    public function getStringAtIndex($sharedStringIndex)
+    {
+        $tempFilePath = $this->getSharedStringTempFilePath($sharedStringIndex);
+        $indexInFile = $sharedStringIndex % $this->maxNumStringsPerTempFile;
+
+        if (!$this->globalFunctionsHelper->file_exists($tempFilePath)) {
+            throw new SharedStringNotFoundException("Shared string temp file not found: $tempFilePath ; for index: $sharedStringIndex");
+        }
+
+        if ($this->inMemoryTempFilePath !== $tempFilePath) {
+            // free memory
+            unset($this->inMemoryTempFileContents);
+
+            $this->inMemoryTempFileContents = explode(PHP_EOL, $this->globalFunctionsHelper->file_get_contents($tempFilePath));
+            $this->inMemoryTempFilePath = $tempFilePath;
+        }
+
+        $sharedString = null;
+        if (array_key_exists($indexInFile, $this->inMemoryTempFileContents)) {
+            $escapedSharedString = $this->inMemoryTempFileContents[$indexInFile];
+            $sharedString = $this->unescapeLineFeed($escapedSharedString);
+        }
+
+        if ($sharedString === null) {
+            throw new SharedStringNotFoundException("Shared string not found for index: $sharedStringIndex");
+        }
+
+        return rtrim($sharedString, PHP_EOL);
+    }
+
+    /**
+     * Escapes the line feed characters (\n)
+     *
+     * @param string $unescapedString
+     * @return string
+     */
+    private function escapeLineFeed($unescapedString)
+    {
+        return str_replace("\n", self::ESCAPED_LINE_FEED_CHARACTER, $unescapedString);
+    }
+
+    /**
+     * Unescapes the line feed characters (\n)
+     *
+     * @param string $escapedString
+     * @return string
+     */
+    private function unescapeLineFeed($escapedString)
+    {
+        return str_replace(self::ESCAPED_LINE_FEED_CHARACTER, "\n", $escapedString);
+    }
+
+    /**
+     * Destroys the cache, freeing memory and removing any created artifacts
+     *
+     * @return void
+     */
+    public function clearCache()
+    {
+        if ($this->tempFolder) {
+            $this->fileSystemHelper->deleteFolderRecursively($this->tempFolder);
+        }
+    }
+}

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

@@ -0,0 +1,82 @@
+<?php
+
+namespace Box\Spout\Reader\Helper\XLSX\SharedStringsCaching;
+use Box\Spout\Reader\Exception\SharedStringNotFoundException;
+
+/**
+ * Class InMemoryStrategy
+ *
+ * This class implements the in-memory caching strategy for shared strings.
+ * This strategy is used when the number of unique strings is low, compared to the memory available.
+ *
+ * @package Box\Spout\Reader\Helper\XLSX\SharedStringsCaching
+ */
+class InMemoryStrategy implements CachingStrategyInterface
+{
+    /** @var \SplFixedArray Array used to cache the shared strings */
+    protected $inMemoryCache;
+
+    /** @var bool Whether the cache has been closed */
+    protected $isCacheClosed;
+
+    /**
+     * @param int $sharedStringsUniqueCount Number of unique shared strings
+     */
+    public function __construct($sharedStringsUniqueCount)
+    {
+        $this->inMemoryCache = new \SplFixedArray($sharedStringsUniqueCount);
+        $this->isCacheClosed = false;
+    }
+
+    /**
+     * Adds the given string to the cache.
+     *
+     * @param string $sharedString The string to be added to the cache
+     * @param int $sharedStringIndex Index of the shared string in the sharedStrings.xml file
+     * @return void
+     */
+    public function addStringForIndex($sharedString, $sharedStringIndex)
+    {
+        if (!$this->isCacheClosed) {
+            $this->inMemoryCache->offsetSet($sharedStringIndex, $sharedString);
+        }
+    }
+
+    /**
+     * Closes the cache after the last shared string was added.
+     * This prevents any additional string from being added to the cache.
+     *
+     * @return void
+     */
+    public function closeCache()
+    {
+        $this->isCacheClosed = true;
+    }
+
+    /**
+     * Returns the string located at the given index from the cache.
+     *
+     * @param int $sharedStringIndex Index of the shared string in the sharedStrings.xml file
+     * @return string The shared string at the given index
+     * @throws \Box\Spout\Reader\Exception\SharedStringNotFoundException If no shared string found for the given index
+     */
+    public function getStringAtIndex($sharedStringIndex)
+    {
+        try {
+            return $this->inMemoryCache->offsetGet($sharedStringIndex);
+        } catch (\RuntimeException $e) {
+            throw new SharedStringNotFoundException("Shared string not found for index: $sharedStringIndex");
+        }
+    }
+
+    /**
+     * Destroys the cache, freeing memory and removing any created artifacts
+     *
+     * @return void
+     */
+    public function clearCache()
+    {
+        unset($this->inMemoryCache);
+        $this->isCacheClosed = false;
+    }
+}

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

@@ -3,8 +3,8 @@
 namespace Box\Spout\Reader\Helper\XLSX;
 
 use Box\Spout\Common\Exception\IOException;
-use Box\Spout\Common\Helper\FileSystemHelper;
-use Box\Spout\Reader\Exception\SharedStringNotFoundException;
+use Box\Spout\Reader\Helper\XLSX\SharedStringsCaching\CachingStrategyFactory;
+use Box\Spout\Reader\Helper\XLSX\SharedStringsCaching\CachingStrategyInterface;
 
 /**
  * Class SharedStringsHelper
@@ -20,43 +20,14 @@ class SharedStringsHelper
     /** Main namespace for the sharedStrings.xml file */
     const MAIN_NAMESPACE_FOR_SHARED_STRINGS_XML = 'http://schemas.openxmlformats.org/spreadsheetml/2006/main';
 
-    /**
-     * To avoid running out of memory when extracting the shared strings, they will be saved to temporary files
-     * instead of in memory. Then, when accessing a string, the corresponding file contents will be loaded in memory
-     * and the string will be quickly retrieved.
-     * The performance bottleneck is not when creating these temporary files, but rather when loading their content.
-     * Because the contents of the last loaded file stays in memory until another file needs to be loaded, it works
-     * best when the indexes of the shared strings are sorted in the sheet data.
-     * 10,000 was chosen because it creates small files that are fast to be loaded in memory.
-     */
-    const MAX_NUM_STRINGS_PER_TEMP_FILE = 10000;
-
-    /** Value to use to escape the line feed character ("\n") */
-    const ESCAPED_LINE_FEED_CHARACTER = '_x000A_';
-
     /** @var string Path of the XLSX file being read */
     protected $filePath;
 
     /** @var string Temporary folder where the temporary files to store shared strings will be stored */
     protected $tempFolder;
 
-    /** @var \Box\Spout\Writer\Helper\XLSX\FileSystemHelper Helper to perform file system operations */
-    protected $fileSystemHelper;
-
-    /** @var resource Pointer to the last temp file a shared string was written to */
-    protected $tempFilePointer;
-
-    /**
-     * @var string Path of the temporary file whose contents is currently stored in memory
-     * @see MAX_NUM_STRINGS_PER_TEMP_FILE
-     */
-    protected $inMemoryTempFilePath;
-
-    /**
-     * @var string Contents of the temporary file that was last read
-     * @see MAX_NUM_STRINGS_PER_TEMP_FILE
-     */
-    protected $inMemoryTempFileContents;
+    /** @var CachingStrategyInterface The best caching strategy for storing shared strings */
+    protected $cachingStrategy;
 
     /**
      * @param string $filePath Path of the XLSX file being read
@@ -65,10 +36,7 @@ class SharedStringsHelper
     public function __construct($filePath, $tempFolder = null)
     {
         $this->filePath = $filePath;
-
-        $rootTempFolder = ($tempFolder) ?: sys_get_temp_dir();
-        $this->fileSystemHelper = new FileSystemHelper($rootTempFolder);
-        $this->tempFolder = $this->fileSystemHelper->createFolder($rootTempFolder, uniqid('sharedstrings'));
+        $this->tempFolder = $tempFolder;
     }
 
     /**
@@ -108,7 +76,6 @@ class SharedStringsHelper
     {
         $xmlReader = new \XMLReader();
         $sharedStringIndex = 0;
-        $this->tempFilePointer = null;
         $escaper = new \Box\Spout\Common\Escaper\XLSX();
 
         $sharedStringsFilePath = $this->getSharedStringsFilePath();
@@ -116,12 +83,15 @@ class SharedStringsHelper
             throw new IOException('Could not open "' . self::SHARED_STRINGS_XML_FILE_PATH . '".');
         }
 
+        $sharedStringsUniqueCount = $this->getSharedStringsUniqueCount($xmlReader);
+        $this->cachingStrategy = $this->getBestSharedStringsCachingStrategy($sharedStringsUniqueCount);
+
         while ($xmlReader->read() && $xmlReader->name !== 'si') {
             // do nothing until a 'si' tag is reached
         }
 
         while ($xmlReader->name === 'si') {
-            $node = new \SimpleXMLElement($xmlReader->readOuterXml());
+            $node = $this->getSimpleXmlElementNodeFromXMLReader($xmlReader);
             $node->registerXPathNamespace('ns', self::MAIN_NAMESPACE_FOR_SHARED_STRINGS_XML);
 
             // removes nodes that should not be read, like the pronunciation of the Kanji characters
@@ -140,12 +110,7 @@ class SharedStringsHelper
             }
 
             $unescapedTextValue = $escaper->unescape($textValue);
-
-            // The shared string retrieval logic expects each cell data to be on one line only
-            // Encoding the line feed character allows to preserve this assumption
-            $lineFeedEncodedTextValue = $this->escapeLineFeed($unescapedTextValue);
-
-            $this->writeSharedStringToTempFile($lineFeedEncodedTextValue, $sharedStringIndex);
+            $this->cachingStrategy->addStringForIndex($unescapedTextValue, $sharedStringIndex);
 
             $sharedStringIndex++;
 
@@ -153,21 +118,91 @@ class SharedStringsHelper
             $xmlReader->next('si');
         }
 
-        // close pointer to the last temp file that was written
-        if ($this->tempFilePointer) {
-            fclose($this->tempFilePointer);
-        }
+        $this->cachingStrategy->closeCache();
 
         $xmlReader->close();
     }
 
     /**
-     * @return string The path to the shared strings XML file, working cross-platforms
+     * @return string The path to the shared strings XML file
      */
     protected function getSharedStringsFilePath()
     {
-        $sharedStringsXmlFilePath = str_replace('/', DIRECTORY_SEPARATOR, self::SHARED_STRINGS_XML_FILE_PATH);
-        return 'zip://' . $this->filePath . '#' . $sharedStringsXmlFilePath;
+        return 'zip://' . $this->filePath . '#' . self::SHARED_STRINGS_XML_FILE_PATH;
+    }
+
+    /**
+     * Returns the shared strings unique count, as specified in <sst> tag.
+     *
+     * @param \XMLReader $xmlReader XMLReader instance
+     * @return int Number of unique shared strings in the sharedStrings.xml file
+     * @throws \Box\Spout\Common\Exception\IOException If sharedStrings.xml is invalid and can't be read
+     */
+    protected function getSharedStringsUniqueCount($xmlReader)
+    {
+        // Use internal errors to avoid displaying lots of warning messages in case of invalid file
+        // For instance, if the file is used to perform a "Billion Laughs" or "Quadratic Blowup" attacks
+        libxml_clear_errors();
+        libxml_use_internal_errors(true);
+
+        $xmlReader->next('sst');
+
+        // Iterate over the "sst" elements to get the actual "sst ELEMENT" (skips any DOCTYPE)
+        while ($xmlReader->name === 'sst' && $xmlReader->nodeType !== \XMLReader::ELEMENT) {
+            $xmlReader->read();
+        }
+
+        $readError = libxml_get_last_error();
+        if ($readError !== false) {
+            throw new IOException("The sharedStrings.xml file is invalid and cannot be read. [{$readError->message}]");
+        }
+
+        // reset the setting to display XML warnings/errors
+        libxml_use_internal_errors(false);
+
+        return intval($xmlReader->getAttribute('uniqueCount'));
+    }
+
+    /**
+     * Returns the best shared strings caching strategy.
+     *
+     * @param int $sharedStringsUniqueCount
+     * @return CachingStrategyInterface
+     */
+    protected function getBestSharedStringsCachingStrategy($sharedStringsUniqueCount)
+    {
+        return CachingStrategyFactory::getInstance()
+                ->getBestCachingStrategy($sharedStringsUniqueCount, $this->tempFolder);
+    }
+
+    /**
+     * Returns a SimpleXMLElement node from the current node in the given XMLReader instance.
+     * This is to simplify the parsing of the subtree.
+     *
+     * @param \XMLReader $xmlReader
+     * @return \SimpleXMLElement
+     * @throws \Box\Spout\Common\Exception\IOException If the current node cannot be read
+     */
+    protected function getSimpleXmlElementNodeFromXMLReader($xmlReader)
+    {
+        // Use internal errors to avoid displaying lots of warning messages in case of error found in the XML node.
+        // For instance, if the file is used to perform a "Billion Laughs" or "Quadratic Blowup" attacks
+        libxml_clear_errors();
+        libxml_use_internal_errors(true);
+
+        $node = null;
+        try {
+            $node = new \SimpleXMLElement($xmlReader->readOuterXml());
+        } catch (\Exception $exception) {
+            $error = libxml_get_last_error();
+            libxml_use_internal_errors(false);
+
+            throw new IOException('The sharedStrings.xml file contains unreadable data [' . trim($error->message) . '].');
+        }
+
+        libxml_use_internal_errors(false);
+
+        return $node;
     }
 
     /**
@@ -220,42 +255,7 @@ class SharedStringsHelper
     }
 
     /**
-     * Writes the given string to its associated temp file.
-     * A new temporary file is created when the previous one has reached its max capacity.
-     *
-     * @param string $sharedString Shared string to write to the temp file
-     * @param int $sharedStringIndex Index of the shared string in the sharedStrings.xml file
-     * @return void
-     */
-    protected function writeSharedStringToTempFile($sharedString, $sharedStringIndex)
-    {
-        $tempFilePath = $this->getSharedStringTempFilePath($sharedStringIndex);
-
-        if (!file_exists($tempFilePath)) {
-            if ($this->tempFilePointer) {
-                fclose($this->tempFilePointer);
-            }
-            $this->tempFilePointer = fopen($tempFilePath, 'w');
-        }
-
-        fwrite($this->tempFilePointer, $sharedString . PHP_EOL);
-    }
-
-    /**
-     * Returns the path for the temp file that should contain the string for the given index
-     *
-     * @param int $sharedStringIndex Index of the shared string in the sharedStrings.xml file
-     * @return string The temp file path for the given index
-     */
-    protected function getSharedStringTempFilePath($sharedStringIndex)
-    {
-        $numTempFile = intval($sharedStringIndex / self::MAX_NUM_STRINGS_PER_TEMP_FILE);
-        return $this->tempFolder . DIRECTORY_SEPARATOR . 'sharedstrings' . $numTempFile;
-    }
-
-    /**
-     * Returns the shared string at the given index.
-     * Because the strings have been split into different files, it looks for the value in the correct file.
+     * Returns the shared string at the given index, using the previously chosen caching strategy.
      *
      * @param int $sharedStringIndex Index of the shared string in the sharedStrings.xml file
      * @return string The shared string at the given index
@@ -263,63 +263,18 @@ class SharedStringsHelper
      */
     public function getStringAtIndex($sharedStringIndex)
     {
-        $tempFilePath = $this->getSharedStringTempFilePath($sharedStringIndex);
-        $indexInFile = $sharedStringIndex % self::MAX_NUM_STRINGS_PER_TEMP_FILE;
-
-        if (!file_exists($tempFilePath)) {
-            throw new SharedStringNotFoundException("Shared string temp file not found: $tempFilePath ; for index: $sharedStringIndex");
-        }
-
-        if ($this->inMemoryTempFilePath !== $tempFilePath) {
-            // free memory
-            unset($this->inMemoryTempFileContents);
-
-            $this->inMemoryTempFileContents = explode(PHP_EOL, file_get_contents($tempFilePath));
-            $this->inMemoryTempFilePath = $tempFilePath;
-        }
-
-        $sharedString = null;
-        if (array_key_exists($indexInFile, $this->inMemoryTempFileContents)) {
-            $escapedSharedString = $this->inMemoryTempFileContents[$indexInFile];
-            $sharedString = $this->unescapeLineFeed($escapedSharedString);
-        }
-
-        if ($sharedString === null) {
-            throw new SharedStringNotFoundException("Shared string not found for index: $sharedStringIndex");
-        }
-
-        return rtrim($sharedString, PHP_EOL);
+        return $this->cachingStrategy->getStringAtIndex($sharedStringIndex);
     }
 
     /**
-     * Escapes the line feed character (\n)
-     *
-     * @param string $unescapedString
-     * @return string
-     */
-    private function escapeLineFeed($unescapedString)
-    {
-        return str_replace("\n", self::ESCAPED_LINE_FEED_CHARACTER, $unescapedString);
-    }
-
-    /**
-     * Unescapes the line feed character (\n)
-     *
-     * @param string $escapedString
-     * @return string
-     */
-    private function unescapeLineFeed($escapedString)
-    {
-        return str_replace(self::ESCAPED_LINE_FEED_CHARACTER, "\n", $escapedString);
-    }
-
-    /**
-     * Deletes the created temporary folder and all its contents
+     * Destroys the cache, freeing memory and removing any created artifacts
      *
      * @return void
      */
     public function cleanup()
     {
-        $this->fileSystemHelper->deleteFolderRecursively($this->tempFolder);
+        if ($this->cachingStrategy) {
+            $this->cachingStrategy->clearCache();
+        }
     }
 }

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

@@ -186,8 +186,7 @@ class WorksheetHelper
      */
     protected function getFileAsXMLElementWithNamespace($xmlFilePath, $mainNamespace)
     {
-        $normalizedXmlFilePath = str_replace('/', DIRECTORY_SEPARATOR, $xmlFilePath);
-        $xmlContents = $this->globalFunctionsHelper->file_get_contents('zip://' . $this->filePath . '#' . $normalizedXmlFilePath);
+        $xmlContents = $this->globalFunctionsHelper->file_get_contents('zip://' . $this->filePath . '#' . $xmlFilePath);
 
         $xmlElement = new \SimpleXMLElement($xmlContents);
         $xmlElement->registerXPathNamespace('ns', $mainNamespace);

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

@@ -33,12 +33,11 @@ class Worksheet
 
     /**
      * @return string Path of the XML file containing the worksheet data,
-     *                without the leading slash and working cross-platforms.
+     *                without the leading slash.
      */
     public function getDataXmlFilePath()
     {
-        $dataXmlFilePath = ltrim($this->dataXmlFilePath, '/');
-        return str_replace('/', DIRECTORY_SEPARATOR, $dataXmlFilePath);
+        return ltrim($this->dataXmlFilePath, '/');
     }
 
     /**

src/Spout/Reader/XLSX.php

@@ -19,6 +19,14 @@ use Box\Spout\Reader\Helper\XLSX\WorksheetHelper;
  */
 class XLSX extends AbstractReader
 {
+    const CELL_TYPE_INLINE_STRING = 'inlineStr';
+    const CELL_TYPE_STR = 'str';
+    const CELL_TYPE_SHARED_STRING = 's';
+    const CELL_TYPE_BOOLEAN = 'b';
+    const CELL_TYPE_NUMERIC = 'n';
+    const CELL_TYPE_DATE = 'd';
+    const CELL_TYPE_ERROR = 'e';
+    
     /** @var string Real path of the file to read */
     protected $filePath;
 
@@ -177,6 +185,7 @@ class XLSX extends AbstractReader
             throw new BadUsageException('You must call nextSheet() before calling hasNextRow() or nextRow()');
         }
 
+        $escaper = new \Box\Spout\Common\Escaper\XLSX();
         $isInsideRowTag = false;
         $rowData = [];
 
@@ -188,6 +197,7 @@ class XLSX extends AbstractReader
                     $lastCellIndex = $matches[1];
                     $this->numberOfColumns = CellHelper::getColumnIndexFromCellIndex($lastCellIndex) + 1;
                 }
+
             } else if ($this->xmlReader->nodeType == \XMLReader::ELEMENT && $this->xmlReader->name === 'row') {
                 // Start of the row description
                 $isInsideRowTag = true;
@@ -200,32 +210,15 @@ class XLSX extends AbstractReader
                     $numberOfColumnsForRow = intval($numberOfColumnsForRow);
                 }
                 $rowData = ($numberOfColumnsForRow !== 0) ? array_fill(0, $numberOfColumnsForRow, '') : [];
+
             } else if ($isInsideRowTag && $this->xmlReader->nodeType == \XMLReader::ELEMENT && $this->xmlReader->name === 'c') {
                 // Start of a cell description
                 $currentCellIndex = $this->xmlReader->getAttribute('r');
                 $currentColumnIndex = CellHelper::getColumnIndexFromCellIndex($currentCellIndex);
+
                 $node = $this->xmlReader->expand();
+                $rowData[$currentColumnIndex] = $this->getCellValue($node, $escaper);
 
-                $hasInlineString = ($this->xmlReader->getAttribute('t') === 'inlineStr');
-                $hasSharedString = ($this->xmlReader->getAttribute('t') === 's');
-
-                if ($hasInlineString) {
-                    // inline strings are formatted this way:
-                    // <c r="A1" t="inlineStr"><is><t>[INLINE_STRING]</t></is></c>
-                    $tNode = $node->getElementsByTagName('t')->item(0);
-                    $rowData[$currentColumnIndex] = trim($tNode->nodeValue);
-                } else if ($hasSharedString) {
-                    // shared strings are formatted this way:
-                    // <c r="A1" t="s"><v>[SHARED_STRING_INDEX]</v></c>
-                    $vNode = $node->getElementsByTagName('v')->item(0);
-                    $sharedStringIndex = intval($vNode->nodeValue);
-                    $rowData[$currentColumnIndex] = $this->sharedStringsHelper->getStringAtIndex($sharedStringIndex);
-                } else {
-                    // other values are formatted this way:
-                    // <c r="A1"><v>[VALUE]</v></c>
-                    $vNode = $node->getElementsByTagName('v')->item(0);
-                    $rowData[$currentColumnIndex] = intval($vNode->nodeValue);
-                }
             } else if ($this->xmlReader->nodeType == \XMLReader::END_ELEMENT && $this->xmlReader->name === 'row') {
                 // End of the row description
                 // If needed, we fill the empty cells
@@ -238,6 +231,149 @@ class XLSX extends AbstractReader
         return ($rowData !== []) ? $rowData : null;
     }
 
+    /**
+     * Returns the cell's string value from a node's nested value node
+     *
+     * @param \DOMNode $node
+     * @return string The value associated with the cell
+     */
+    protected function getVNodeValue($node)
+    {
+        // for cell types having a "v" tag containing the value.
+        // if not, the returned value should be empty string.
+        $vNode = $node->getElementsByTagName('v')->item(0);
+        if ($vNode !== null) {
+            return $vNode->nodeValue;
+        }
+        return "";
+    }
+
+    /**
+     * Returns the cell String value where string is inline.
+     *
+     * @param \DOMNode $node
+     * @param \Box\Spout\Common\Escaper\XLSX $escaper
+     * @return string The value associated with the cell (null when the cell has an error)
+     */
+    protected function formatInlineStringCellValue($node, $escaper)
+    {
+        // inline strings are formatted this way:
+        // <c r="A1" t="inlineStr"><is><t>[INLINE_STRING]</t></is></c>
+        $tNode = $node->getElementsByTagName('t')->item(0);
+        $escapedCellValue = trim($tNode->nodeValue);
+        $cellValue = $escaper->unescape($escapedCellValue);
+        return $cellValue;
+    }
+
+    /**
+     * Returns the cell String value from shared-strings file using nodeValue index.
+     *
+     * @param string $nodeValue
+     * @param \Box\Spout\Common\Escaper\XLSX $escaper
+     * @return string The value associated with the cell (null when the cell has an error)
+     */
+    protected function formatSharedStringCellValue($nodeValue, $escaper)
+    {
+        // shared strings are formatted this way:
+        // <c r="A1" t="s"><v>[SHARED_STRING_INDEX]</v></c>
+        $sharedStringIndex = intval($nodeValue);
+        $escapedCellValue = $this->sharedStringsHelper->getStringAtIndex($sharedStringIndex);
+        $cellValue = $escaper->unescape($escapedCellValue);
+        return $cellValue;
+    }
+
+    /**
+     * Returns the cell String value, where string is stored in value node.
+     *
+     * @param string $nodeValue
+     * @param \Box\Spout\Common\Escaper\XLSX $escaper
+     * @return string The value associated with the cell (null when the cell has an error)
+     */
+    protected function formatStrCellValue($nodeValue, $escaper)
+    {
+        $escapedCellValue = trim($nodeValue);
+        $cellValue = $escaper->unescape($escapedCellValue);
+        return $cellValue;
+    }
+
+    /**
+     * Returns the cell Numeric value from string of nodeValue.
+     *
+     * @param string $nodeValue
+     * @param \Box\Spout\Common\Escaper\XLSX $escaper
+     * @return int|float The value associated with the cell
+     */
+    protected function formatNumericCellValue($nodeValue)
+    {
+        $cellValue = is_int($nodeValue) ? intval($nodeValue) : floatval($nodeValue);
+        return $cellValue;
+    }
+
+    /**
+     * Returns the cell Boolean value from a specific node's Value.
+     *
+     * @param string $nodeValue
+     * @return bool The value associated with the cell
+     */
+    protected function formatBooleanCellValue($nodeValue)
+    {
+        // !! is similar to boolval()
+        $cellValue = !!$nodeValue;
+        return $cellValue;
+    }
+
+    /**
+     * Returns a cell's PHP Date value, associated to the given stored nodeValue.
+     *
+     * @param string $nodeValue
+     * @param \Box\Spout\Common\Escaper\XLSX $escaper
+     * @return DateTime|null The value associated with the cell (null when the cell has an error)
+     */
+    protected function formatDateCellValue($nodeValue)
+    {
+        try { // Mitigate thrown Exception on invalid date-time format (http://php.net/manual/en/datetime.construct.php)
+            $cellValue = new \DateTime($nodeValue);
+            return $cellValue;
+        } catch (\Exception $e) {
+            return null;
+        }
+    }
+
+    /**
+     * Returns the (unescaped) correctly marshalled, cell value associated to the given XML node.
+     *
+     * @param \DOMNode $node
+     * @param \Box\Spout\Common\Escaper\XLSX $escaper
+     * @return string|int|float|bool|null The value associated with the cell (null when the cell has an error)
+     */
+    protected function getCellValue($node, $escaper)
+    {
+        // Default cell type is "n"
+        $cellType = $node->getAttribute('t') ?: 'n';
+        $vNodeValue = $this->getVNodeValue($node);
+        if ( ($vNodeValue === "") && ($cellType !== self::CELL_TYPE_INLINE_STRING) ) {
+            return $vNodeValue;
+        }
+
+        switch ($cellType)
+        {
+            case self::CELL_TYPE_INLINE_STRING:
+                return $this->formatInlineStringCellValue($node, $escaper);
+            case self::CELL_TYPE_SHARED_STRING:
+                return $this->formatSharedStringCellValue($vNodeValue, $escaper);
+            case self::CELL_TYPE_STR:
+                return $this->formatStrCellValue($vNodeValue, $escaper);
+            case self::CELL_TYPE_BOOLEAN:
+                return $this->formatBooleanCellValue($vNodeValue);
+            case self::CELL_TYPE_NUMERIC:
+                return $this->formatNumericCellValue($vNodeValue);
+            case self::CELL_TYPE_DATE:
+                return $this->formatDateCellValue($vNodeValue);
+            default:
+                return null;
+        }
+    }
+
     /**
      * Closes the reader. To be used after reading the file.
      *

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

@@ -36,7 +36,7 @@ EOD;
      */
     public function __construct($xlFolder)
     {
-        $sharedStringsFilePath = $xlFolder . DIRECTORY_SEPARATOR . self::SHARED_STRINGS_FILE_NAME;
+        $sharedStringsFilePath = $xlFolder . '/' . self::SHARED_STRINGS_FILE_NAME;
         $this->sharedStringsFilePointer = fopen($sharedStringsFilePath, 'w');
 
         $this->throwIfSharedStringsFilePointerIsNotAvailable();

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

@@ -33,18 +33,30 @@ class ZipHelper
      */
     protected function addFolderToZip($zip, $folderPath)
     {
-        $folderRealPath = realpath($folderPath) . DIRECTORY_SEPARATOR;
+        $folderRealPath = $this->getNormalizedRealPath($folderPath) . '/';
         $itemIterator = new \RecursiveIteratorIterator(new \RecursiveDirectoryIterator($folderPath, \RecursiveDirectoryIterator::SKIP_DOTS), \RecursiveIteratorIterator::SELF_FIRST);
 
         foreach ($itemIterator as $itemInfo) {
-            $itemRealPath = realpath($itemInfo->getPathname());
+            $itemRealPath = $this->getNormalizedRealPath($itemInfo->getPathname());
             $itemLocalPath = str_replace($folderRealPath, '', $itemRealPath);
 
             if ($itemInfo->isFile()) {
-                $zip->addFile($itemInfo->getPathname(), $itemLocalPath);
+                $zip->addFile($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/Internal/XLSX/Worksheet.php

@@ -56,7 +56,7 @@ EOD;
 
         $this->stringsEscaper = new \Box\Spout\Common\Escaper\XLSX();
 
-        $this->worksheetFilePath = $worksheetFilesFolder . DIRECTORY_SEPARATOR . strtolower($this->externalSheet->getName()) . '.xml';
+        $this->worksheetFilePath = $worksheetFilesFolder . '/' . strtolower($this->externalSheet->getName()) . '.xml';
         $this->startSheet();
     }
 

tests/Spout/Reader/CSVTest.php

@@ -19,11 +19,61 @@ class CSVTest extends \PHPUnit_Framework_TestCase
      *
      * @return void
      */
-    public function testReadShouldThrowExceptionIfFileDoesNotExist()
+    public function testOpenShouldThrowExceptionIfFileDoesNotExist()
     {
-        $this->getAllRowsForFile('/path/to/fake/file.csv');
+        ReaderFactory::create(Type::CSV)->open('/path/to/fake/file.csv');
     }
 
+    /**
+     * @expectedException \Box\Spout\Common\Exception\IOException
+     *
+     * @return void
+     */
+    public function testOpenShouldThrowExceptionIfFileNotReadable()
+    {
+        $helperStub = $this->getMockBuilder('\Box\Spout\Common\Helper\GlobalFunctionsHelper')
+                        ->setMethods(['is_readable'])
+                        ->getMock();
+        $helperStub->method('is_readable')->willReturn(false);
+
+        $resourcePath = $this->getResourcePath('csv_standard.csv');
+
+        $reader = ReaderFactory::create(Type::CSV);
+        $reader->setGlobalFunctionsHelper($helperStub);
+        $reader->open($resourcePath);
+    }
+
+    /**
+     * @expectedException \Box\Spout\Reader\Exception\ReaderNotOpenedException
+     *
+     * @return void
+     */
+    public function testReadShouldThrowExceptionIfReadBeforeReaderOpened()
+    {
+        $reader = ReaderFactory::create(Type::CSV);
+        $reader->hasNextRow();
+    }
+
+    /**
+     * @expectedException \Box\Spout\Reader\Exception\EndOfFileReachedException
+     *
+     * @return void
+     */
+    public function testReadShouldThrowExceptionIfNextRowCalledAfterReadingDone()
+    {
+        $resourcePath = $this->getResourcePath('csv_standard.csv');
+
+        $reader = ReaderFactory::create(Type::CSV);
+        $reader->open($resourcePath);
+
+        while ($reader->hasNextRow()) {
+            $reader->nextRow();
+        }
+
+        $reader->nextRow();
+    }
+
+
     /**
      * @return void
      */

tests/Spout/Reader/Helper/XLSX/SharedStringsCaching/CachingStrategyFactoryTest.php

@@ -0,0 +1,99 @@
+<?php
+
+namespace Box\Spout\Reader\Helper\XLSX\SharedStringsCaching;
+
+/**
+ * Class CachingStrategyFactoryTest
+ *
+ * @package Box\Spout\Reader\Helper\XLSX\SharedStringsCaching
+ */
+class CachingStrategyFactoryTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * @return array
+     */
+    public function dataProviderForTestGetBestCachingStrategy()
+    {
+        return [
+            [CachingStrategyFactory::MAX_NUM_STRINGS_PER_TEMP_FILE, -1, 'FileBasedStrategy'],
+            [CachingStrategyFactory::MAX_NUM_STRINGS_PER_TEMP_FILE + 10, -1, 'FileBasedStrategy'],
+            [CachingStrategyFactory::MAX_NUM_STRINGS_PER_TEMP_FILE - 10, -1, 'InMemoryStrategy'],
+            [10 , CachingStrategyFactory::AMOUNT_MEMORY_NEEDED_PER_STRING_IN_KB * 10, 'FileBasedStrategy'],
+            [15, CachingStrategyFactory::AMOUNT_MEMORY_NEEDED_PER_STRING_IN_KB * 10, 'FileBasedStrategy'],
+            [5 , CachingStrategyFactory::AMOUNT_MEMORY_NEEDED_PER_STRING_IN_KB * 10, 'InMemoryStrategy'],
+        ];
+    }
+
+    /**
+     * @dataProvider dataProviderForTestGetBestCachingStrategy
+     *
+     * @param int $sharedStringsUniqueCount
+     * @param int $memoryLimitInKB
+     * @param string $expectedStrategyClassName
+     * @return void
+     */
+    public function testGetBestCachingStrategy($sharedStringsUniqueCount, $memoryLimitInKB, $expectedStrategyClassName)
+    {
+        /** @var CachingStrategyFactory|\PHPUnit_Framework_MockObject_MockObject $factoryStub */
+        $factoryStub = $this
+            ->getMockBuilder('\Box\Spout\Reader\Helper\XLSX\SharedStringsCaching\CachingStrategyFactory')
+            ->disableOriginalConstructor()
+            ->setMethods(['getMemoryLimitInKB'])
+            ->getMock();
+
+        $factoryStub->method('getMemoryLimitInKB')->willReturn($memoryLimitInKB);
+
+        \ReflectionHelper::setStaticValue('\Box\Spout\Reader\Helper\XLSX\SharedStringsCaching\CachingStrategyFactory', 'instance', $factoryStub);
+
+        $strategy = $factoryStub->getBestCachingStrategy($sharedStringsUniqueCount, null);
+
+        $fullExpectedStrategyClassName = 'Box\Spout\Reader\Helper\XLSX\SharedStringsCaching\\' . $expectedStrategyClassName;
+        $this->assertEquals($fullExpectedStrategyClassName, get_class($strategy));
+
+        $strategy->clearCache();
+        \ReflectionHelper::reset();
+    }
+
+    /**
+     * @return array
+     */
+    public function dataProviderForTestGetMemoryLimitInKB()
+    {
+        return [
+            ['-1', -1],
+            ['invalid', -1],
+            ['1024B', 1],
+            ['128K', 128],
+            ['256KB', 256],
+            ['512M', 512 * 1024],
+            ['2MB', 2 * 1024],
+            ['1G', 1 * 1024 * 1024],
+            ['10GB', 10 * 1024 * 1024],
+            ['2T', 2 * 1024 * 1024 * 1024],
+            ['5TB', 5 * 1024 * 1024 * 1024],
+        ];
+    }
+
+    /**
+     * @dataProvider dataProviderForTestGetMemoryLimitInKB
+     *
+     * @param string $memoryLimitFormatted
+     * @param float $expectedMemoryLimitInKB
+     * @return void
+     */
+    public function testGetMemoryLimitInKB($memoryLimitFormatted, $expectedMemoryLimitInKB)
+    {
+        /** @var CachingStrategyFactory|\PHPUnit_Framework_MockObject_MockObject $factoryStub */
+        $factoryStub = $this
+            ->getMockBuilder('\Box\Spout\Reader\Helper\XLSX\SharedStringsCaching\CachingStrategyFactory')
+            ->disableOriginalConstructor()
+            ->setMethods(['getMemoryLimitFromIni'])
+            ->getMock();
+
+        $factoryStub->method('getMemoryLimitFromIni')->willReturn($memoryLimitFormatted);
+
+        $memoryLimitInKB = \ReflectionHelper::callMethodOnObject($factoryStub, 'getMemoryLimitInKB');
+
+        $this->assertEquals($expectedMemoryLimitInKB, $memoryLimitInKB);
+    }
+}

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

@@ -2,6 +2,9 @@
 
 namespace Box\Spout\Reader\Helper\XLSX;
 
+use Box\Spout\Reader\Helper\XLSX\SharedStringsCaching\CachingStrategyFactory;
+use Box\Spout\Reader\Helper\XLSX\SharedStringsCaching\FileBasedStrategy;
+use Box\Spout\Reader\Helper\XLSX\SharedStringsCaching\InMemoryStrategy;
 use Box\Spout\TestUsingResource;
 
 /**
@@ -33,46 +36,6 @@ class SharedStringsHelperTest extends \PHPUnit_Framework_TestCase
         $this->sharedStringsHelper->cleanup();
     }
 
-    /**
-     * @return void
-     */
-    public function testExtractSharedStringsShouldCreateTempFileWithSharedStrings()
-    {
-        $this->sharedStringsHelper->extractSharedStrings();
-
-        $tempFolder = \ReflectionHelper::getValueOnObject($this->sharedStringsHelper, 'tempFolder');
-
-        $filesInTempFolder = $this->getFilesInFolder($tempFolder);
-        $this->assertEquals(1, count($filesInTempFolder), 'One temp file should have been created in the temp folder.');
-
-        $tempFileContents = file_get_contents($filesInTempFolder[0]);
-        $tempFileContentsPerLine = explode(PHP_EOL, $tempFileContents);
-
-        $this->assertEquals('s1--A1', $tempFileContentsPerLine[0]);
-        $this->assertEquals('s1--E5', $tempFileContentsPerLine[24]);
-    }
-
-    /**
-     * Returns all files that are in the given folder.
-     * It does not include "." and ".." and is not recursive.
-     *
-     * @param string $folderPath
-     * @return array
-     */
-    private function getFilesInFolder($folderPath)
-    {
-        $files = [];
-        $directoryIterator = new \DirectoryIterator($folderPath);
-
-        foreach ($directoryIterator as $fileInfo) {
-            if ($fileInfo->isFile()) {
-                $files[] = $fileInfo->getPathname();
-            }
-        }
-
-        return $files;
-    }
-
     /**
      * @expectedException \Box\Spout\Reader\Exception\SharedStringNotFoundException
      * @return void
@@ -95,6 +58,9 @@ class SharedStringsHelperTest extends \PHPUnit_Framework_TestCase
 
         $sharedString = $this->sharedStringsHelper->getStringAtIndex(24);
         $this->assertEquals('s1--E5', $sharedString);
+
+        $usedCachingStrategy = \ReflectionHelper::getValueOnObject($this->sharedStringsHelper, 'cachingStrategy');
+        $this->assertTrue($usedCachingStrategy instanceof InMemoryStrategy);
     }
 
     /**
@@ -115,4 +81,32 @@ class SharedStringsHelperTest extends \PHPUnit_Framework_TestCase
 
         $sharedStringsHelper->cleanup();
     }
+
+    /**
+     * @return void
+     */
+    public function testGetStringAtIndexWithFileBasedStrategy()
+    {
+        // force the file-based strategy by setting no memory limit
+        $originalMemoryLimit = ini_get('memory_limit');
+        ini_set('memory_limit', '-1');
+
+        $resourcePath = $this->getResourcePath('sheet_with_lots_of_shared_strings.xlsx');
+        $sharedStringsHelper = new SharedStringsHelper($resourcePath);
+
+        $sharedStringsHelper->extractSharedStrings();
+
+        $sharedString = $sharedStringsHelper->getStringAtIndex(0);
+        $this->assertEquals('str', $sharedString);
+
+        $sharedString = $sharedStringsHelper->getStringAtIndex(CachingStrategyFactory::MAX_NUM_STRINGS_PER_TEMP_FILE + 1);
+        $this->assertEquals('str', $sharedString);
+
+        $usedCachingStrategy = \ReflectionHelper::getValueOnObject($sharedStringsHelper, 'cachingStrategy');
+        $this->assertTrue($usedCachingStrategy instanceof FileBasedStrategy);
+
+        $sharedStringsHelper->cleanup();
+
+        ini_set('memory_limit', $originalMemoryLimit);
+    }
 }

tests/Spout/Reader/XLSXTest.php

@@ -2,6 +2,7 @@
 
 namespace Box\Spout\Reader;
 
+use Box\Spout\Common\Exception\IOException;
 use Box\Spout\Common\Type;
 use Box\Spout\TestUsingResource;
 
@@ -114,6 +115,29 @@ class XLSXTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals($expectedRows, $allRows);
     }
 
+    /**
+     * @return void
+     */
+    public function testReadShouldSupportAllCellTypes()
+    {
+        $allRows = $this->getAllRowsForFile('sheet_with_all_cell_types.xlsx');
+
+        $expectedRows = [
+            [
+                's1--A1', 's1--A2',
+                false, true,
+                \DateTime::createFromFormat('Y-m-d H:i:s', '2015-06-03 13:21:58'),
+                \DateTime::createFromFormat('Y-m-d H:i:s', '2015-06-01 00:00:00'),
+                10, 10.43,
+                null,
+                'weird string', // valid 'str' string
+                null, // invalid date
+            ],
+            ['', '', '', '', '', '', '', '', ''],
+        ];
+        $this->assertEquals($expectedRows, $allRows);
+    }
+
     /**
      * @return void
      */
@@ -222,18 +246,39 @@ class XLSXTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals($expectedRow, $allRows[0], 'Pronunciation data should be removed.');
     }
 
+
     /**
+     * @return array
+     */
+    public function dataProviderForTestReadShouldBeProtectedAgainstAttacks()
+    {
+        return [
+            ['attack_billion_laughs.xlsx'],
+            ['attack_quadratic_blowup.xlsx'],
+        ];
+    }
+
+    /**
+     * @dataProvider dataProviderForTestReadShouldBeProtectedAgainstAttacks
+     * @NOTE: The LIBXML_NOENT is used to ACTUALLY substitute entities (and should therefore not be used)
+     *
+     * @param string $fileName
      * @return void
      */
-    public function testReadShouldBeProtectedAgainstBillionLaughsAttack()
+    public function testReadShouldBeProtectedAgainstAttacks($fileName)
     {
-        $allRows = $this->getAllRowsForFile('billion_laughs_test_file.xlsx');
+        $startTime = microtime(true);
 
-        $expectedMaxMemoryUsage = 20 * 1024 * 1024; // 20MB
-        $this->assertLessThan($expectedMaxMemoryUsage, memory_get_peak_usage(true), 'Entities should not be expanded and therefore consume all the memory.');
+        try {
+            $this->getAllRowsForFile($fileName);
+            $this->fail('An exception should have been thrown');
+        } catch (IOException $exception) {
+            $duration = microtime(true) - $startTime;
+            $this->assertLessThan(10, $duration, 'Entities should not be expanded and therefore take more than 10 seconds to be parsed.');
 
-        $expectedFirstRow = ['s1--A1', 's1--B1', 's1--C1', 's1--D1', 's1--E1'];
-        $this->assertEquals($expectedFirstRow, $allRows[0], 'Entities should be ignored when reading XML files.');
+            $expectedMaxMemoryUsage = 30 * 1024 * 1024; // 30MB
+            $this->assertLessThan($expectedMaxMemoryUsage, memory_get_peak_usage(true), 'Entities should not be expanded and therefore consume all the memory.');
+        }
     }
 
     /**

tests/Spout/ReflectionHelper.php

@@ -89,4 +89,27 @@ class ReflectionHelper
 
         return $value;
     }
+
+    /**
+     * Invoke a the given public or protected method on the given object.
+     *
+     * @param object $object
+     * @param string $methodName
+     * @param *mixed|null $params
+     *
+     * @return mixed|null
+     */
+    public static function callMethodOnObject($object, $methodName)
+    {
+        $params = func_get_args();
+        array_shift($params); // object
+        array_shift($params); // methodName
+
+        $className = get_class($object);
+        $class = new ReflectionClass($className);
+        $method = $class->getMethod($methodName);
+        $method->setAccessible(true);
+
+        return $method->invokeArgs($object, $params);
+    }
 }

tests/Spout/Writer/SheetTest.php

@@ -90,18 +90,9 @@ class SheetTest extends \PHPUnit_Framework_TestCase
      */
     private function assertSheetNameEquals($expectedName, $resourcePath, $message = '')
     {
-        $pathToWorkbookFile = $resourcePath . $this->normalizePath('#xl/workbook.xml');
+        $pathToWorkbookFile = $resourcePath . '#xl/workbook.xml';
         $xmlContents = file_get_contents('zip://' . $pathToWorkbookFile);
 
         $this->assertContains('<sheet name="' . $expectedName . '"', $xmlContents, $message);
     }
-
-    /**
-     * @param string $path
-     * @return string The path with the correct directory separators, as defined for the current platform
-     */
-    private function normalizePath($path)
-    {
-        return str_replace('/', DIRECTORY_SEPARATOR, $path);
-    }
 }

tests/Spout/Writer/XLSXTest.php

@@ -408,7 +408,7 @@ class XLSXTest extends \PHPUnit_Framework_TestCase
     private function assertInlineDataWasWrittenToSheet($fileName, $sheetIndex, $inlineData, $message = '')
     {
         $resourcePath = $this->getGeneratedResourcePath($fileName);
-        $pathToSheetFile = $resourcePath . $this->normalizePath('#xl/worksheets/sheet' . $sheetIndex . '.xml');
+        $pathToSheetFile = $resourcePath . '#xl/worksheets/sheet' . $sheetIndex . '.xml';
         $xmlContents = file_get_contents('zip://' . $pathToSheetFile);
 
         $this->assertContains((string)$inlineData, $xmlContents, $message);
@@ -424,7 +424,7 @@ class XLSXTest extends \PHPUnit_Framework_TestCase
     private function assertInlineDataWasNotWrittenToSheet($fileName, $sheetIndex, $inlineData, $message = '')
     {
         $resourcePath = $this->getGeneratedResourcePath($fileName);
-        $pathToSheetFile = $resourcePath . $this->normalizePath('#xl/worksheets/sheet' . $sheetIndex . '.xml');
+        $pathToSheetFile = $resourcePath . '#xl/worksheets/sheet' . $sheetIndex . '.xml';
         $xmlContents = file_get_contents('zip://' . $pathToSheetFile);
 
         $this->assertNotContains((string)$inlineData, $xmlContents, $message);
@@ -439,18 +439,9 @@ class XLSXTest extends \PHPUnit_Framework_TestCase
     private function assertSharedStringWasWritten($fileName, $sharedString, $message = '')
     {
         $resourcePath = $this->getGeneratedResourcePath($fileName);
-        $pathToSharedStringsFile = $resourcePath . $this->normalizePath('#xl/sharedStrings.xml');
+        $pathToSharedStringsFile = $resourcePath . '#xl/sharedStrings.xml';
         $xmlContents = file_get_contents('zip://' . $pathToSharedStringsFile);
 
         $this->assertContains($sharedString, $xmlContents, $message);
     }
-
-    /**
-     * @param string $path
-     * @return string The path with the correct directory separators, as defined for the current platform
-     */
-    private function normalizePath($path)
-    {
-        return str_replace('/', DIRECTORY_SEPARATOR, $path);
-    }
 }