X-Git-Url: https://git.mxchange.org/?p=core.git;a=blobdiff_plain;f=inc%2Fclasses%2Fmain%2Ffile_directories%2Fclass_BaseFile.php;h=806745d11c2a8716d35a7cda0ac08ec80005baa8;hp=bcc61661bba3d15533f1bbb5c51632daebf1dc7f;hb=81fbc762e1dd894060f110da8f9ee244a53fa6b0;hpb=3433b4b31083b8d3db3d2a30676dd45ddc7321c8

diff --git a/inc/classes/main/file_directories/class_BaseFile.php b/inc/classes/main/file_directories/class_BaseFile.php
index bcc61661..806745d1 100644
--- a/inc/classes/main/file_directories/class_BaseFile.php
+++ b/inc/classes/main/file_directories/class_BaseFile.php
@@ -22,20 +22,120 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 class BaseFile extends BaseFrameworkSystem {
+	/**
+	 * Separator for header data
+	 */
+	const SEPARATOR_HEADER_DATA = 0x01;
+
+	/**
+	 * Separator header->entries
+	 */
+	const SEPARATOR_HEADER_ENTRIES = 0x02;
+
+	/**
+	 * Separator hash->name
+	 */
+	const SEPARATOR_HASH_NAME = 0x03;
+
+	/**
+	 * Separator entry->entry
+	 */
+	const SEPARATOR_ENTRIES = 0x04;
+
+	/**
+	 * Separator type->position
+	 */
+	const SEPARATOR_TYPE_POSITION = 0x05;
+
+	/**
+	 * Length of count
+	 */
+	const LENGTH_COUNT = 20;
+
+	/**
+	 * Length of position
+	 */
+	const LENGTH_POSITION = 20;
+
+	/**
+	 * Length of name
+	 */
+	const LENGTH_NAME = 10;
+
+	/**
+	 * Maximum length of entry type
+	 */
+	const LENGTH_TYPE = 20;
+
+	//***** Array elements for 'gaps' array *****
+
+	/**
+	 * Start of gap
+	 */
+	const GAPS_INDEX_START = 'start';
+
+	/**
+	 * End of gap
+	 */
+	const GAPS_INDEX_END = 'end';
+
+	/**
+	 * Counter for total entries
+	 */
+	private $totalEntries = 0;
+
+	/**
+	 * Current seek position
+	 */
+	private $seekPosition = 0;
+
+	/**
+	 * Size of header
+	 */
+	private $headerSize = 0;
+
+	/**
+	 * File header
+	 */
+	private $header = array();
+
+	/**
+	 * Seek positions for gaps ("fragmentation")
+	 */
+	private $gaps = array();
+
+	/**
+	 * Seek positions for damaged entries (e.g. mismatching hash sum, ...)
+	 */
+	private $damagedEntries = array();
+
 	/**
 	 * The current file we are working in
 	 */
 	private $fileName = '';
 
+	/**
+	 * Back-buffer
+	 */
+	private $backBuffer = '';
+
+	/**
+	 * Currently loaded block (will be returned by current())
+	 */
+	private $currentBlock = '';
+
 	/**
 	 * Protected constructor
 	 *
 	 * @param	$className	Name of the class
-	 * @return	void
+y	 * @return	void
 	 */
 	protected function __construct ($className) {
 		// Call parent constructor
 		parent::__construct($className);
+
+		// Init counters and gaps array
+		$this->initCountersGapsArray();
 	}
 
 	/**
@@ -52,17 +152,195 @@ class BaseFile extends BaseFrameworkSystem {
 	}
 
 	/**
-	 * Close a file source and set it's instance to null and the file name
-	 * to empty
+	 * Initializes counter for valid entries, arrays for damaged entries and
+	 * an array for gap seek positions. If you call this method on your own,
+	 * please re-analyze the file structure. So you are better to call
+	 * analyzeFile() instead of this method.
 	 *
 	 * @return	void
-	 * @todo	~10% done?
 	 */
-	public function closeFile () {
-		$this->partialStub('Unfinished method.');
+	public function initCountersGapsArray () {
+		// Init counter and seek position
+		$this->setCounter(0);
+		$this->setSeekPosition(0);
 
-		// Remove file name
-		$this->setFileName('');
+		// Init arrays
+		$this->gaps = array();
+		$this->damagedEntries = array();
+	}
+
+	/**
+	 * Getter for total entries
+	 *
+	 * @return	$totalEntries	Total entries in this file
+	 */
+	protected final function getCounter () {
+		// Get it
+		return $this->totalEntries;
+	}
+
+	/**
+	 * Setter for total entries
+	 *
+	 * @param	$totalEntries	Total entries in this file
+	 * @return	void
+	 */
+	protected final function setCounter ($counter) {
+		// Set it
+		$this->totalEntries = $counter;
+	}
+
+	/**
+	 * Increment counter
+	 *
+	 * @return	void
+	 */
+	protected final function incrementCounter () {
+		// Get it
+		$this->totalEntries++;
+	}
+
+	/**
+	 * Getter for header size
+	 *
+	 * @return	$totalEntries	Size of file header
+	 */
+	public final function getHeaderSize () {
+		// Get it
+		return $this->headerSize;
+	}
+
+	/**
+	 * Setter for header size
+	 *
+	 * @param	$headerSize		Size of file header
+	 * @return	void
+	 */
+	public final function setHeaderSize ($headerSize) {
+		// Set it
+		$this->headerSize = $headerSize;
+	}
+
+	/**
+	 * Getter for header array
+	 *
+	 * @return	$totalEntries	Size of file header
+	 */
+	public final function getHeader () {
+		// Get it
+		return $this->header;
+	}
+
+	/**
+	 * Setter for header
+	 *
+	 * @param	$header		Array for a file header
+	 * @return	void
+	 */
+	public final function setHeader (array $header) {
+		// Set it
+		$this->header = $header;
+	}
+
+	/**
+	 * Getter for seek position
+	 *
+	 * @return	$seekPosition	Current seek position (stored here in object)
+	 */
+	protected final function getSeekPosition () {
+		// Get it
+		return $this->seekPosition;
+	}
+
+	/**
+	 * Setter for seek position
+	 *
+	 * @param	$seekPosition	Current seek position (stored here in object)
+	 * @return	void
+	 */
+	protected final function setSeekPosition ($seekPosition) {
+		// And set it
+		$this->seekPosition = $seekPosition;
+	}
+
+	/**
+	 * Updates seekPosition attribute from file to avoid to much access on file.
+	 *
+	 * @return	void
+	 */
+	public function updateSeekPosition () {
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
+
+		// Get key (= seek position)
+		$seekPosition = $this->key();
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Setting seekPosition=%s', __METHOD__, __LINE__, $seekPosition));
+
+		// And set it here
+		$this->setSeekPosition($seekPosition);
+
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
+	}
+
+	/**
+	 * Seeks to beginning of file, updates seek position in this object and
+	 * flushes the header.
+	 *
+	 * @return	void
+	 */
+	protected function rewindUpdateSeekPosition () {
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
+
+		// flushFileHeader must be callable
+		assert(is_callable(array($this, 'flushFileHeader')));
+
+		// Seek to beginning of file
+		$this->rewind();
+
+		// And update seek position ...
+		$this->updateSeekPosition();
+
+		// ... to write it back into the file
+		$this->flushFileHeader();
+
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!!', __METHOD__, __LINE__));
+	}
+
+	/**
+	 * Seeks to old position
+	 *
+	 * @return	void
+	 */
+	protected function seekToOldPosition () {
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
+
+		// Seek to currently ("old") saved position
+		$this->seek($this->getSeekPosition());
+
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!!', __METHOD__, __LINE__));
+	}
+
+	/**
+	 * Checks whether the block separator has been found
+	 *
+	 * @param	$str		String to look in
+	 * @return	$isFound	Whether the block separator has been found
+	 */
+	public static function isBlockSeparatorFound ($str) {
+		// Determine it
+		$isFound = (strpos($str, chr(self::SEPARATOR_ENTRIES)) !== FALSE);
+
+		// Return result
+		return $isFound;
+	}
+
+	/**
+	 * Getter for the file pointer
+	 *
+	 * @return	$filePointer	The file pointer which shall be a valid file resource
+	 * @throws	UnsupportedOperationException	If this method is called
+	 */
+	public final function getPointer () {
+		throw new UnsupportedOperationException(array($this, __FUNCTION__), self::EXCEPTION_UNSPPORTED_OPERATION);
 	}
 
 	/**
@@ -85,14 +363,264 @@ class BaseFile extends BaseFrameworkSystem {
 		return $this->fileName;
 	}
 
+	/**
+	 * Initializes the back-buffer by setting it to an empty string.
+	 *
+	 * @return	void
+	 */
+	private function initBackBuffer () {
+		// Simply call the setter
+		$this->setBackBuffer('');
+	}
+
+	/**
+	 * Setter for backBuffer field
+	 *
+	 * @param	$backBuffer		Characters to "store" in back-buffer
+	 * @return	void
+	 */
+	private function setBackBuffer ($backBuffer) {
+		// Cast to string (so no arrays or objects)
+		$backBuffer = (string) $backBuffer;
+
+		// ... and set it
+		$this->backBuffer = $backBuffer;
+	}
+
+	/**
+	 * Getter for backBuffer field
+	 *
+	 * @return	$backBuffer		Characters "stored" in back-buffer
+	 */
+	private function getBackBuffer () {
+		return $this->backBuffer;
+	}
+
+	/**
+	 * Setter for currentBlock field
+	 *
+	 * @param	$currentBlock		Characters to set a currently loaded block
+	 * @return	void
+	 */
+	private function setCurrentBlock ($currentBlock) {
+		// Cast to string (so no arrays or objects)
+		$currentBlock = (string) $currentBlock;
+
+		// ... and set it
+		$this->currentBlock = $currentBlock;
+	}
+
+	/**
+	 * Gets currently read data
+	 *
+	 * @return	$current	Currently read data
+	 */
+	public function getCurrentBlock () {
+		// Return it
+		return $this->currentBlock;
+	}
+
+	/**
+	 * Initializes this file class
+	 *
+	 * @param	$fileName	Name of this abstract file
+	 * @return	void
+	 */
+	protected function initFile ($fileName) {
+		// Get a file i/o pointer instance
+		$pointerInstance = ObjectFactory::createObjectByConfiguredName('file_raw_input_output_class', array($fileName));
+
+		// ... and set it here
+		$this->setPointerInstance($pointerInstance);
+	}
+
+	/**
+	 * Writes data at given position
+	 *
+	 * @param	$seekPosition	Seek position
+	 * @param	$data			Data to be written
+	 * @param	$flushHeader	Whether to flush the header (default: flush)
+	 * @return	void
+	 */
+	protected function writeData ($seekPosition, $data, $flushHeader = TRUE) {
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] seekPosition=%s,data()=%s - CALLED!', __METHOD__, __LINE__, $seekPosition, strlen($data)));
+
+		// Write data at given position
+		$this->getPointerInstance()->writeAtPosition($seekPosition, $data);
+
+		// Update seek position
+		$this->updateSeekPosition();
+
+		// Flush the header?
+		if ($flushHeader === TRUE) {
+			// Flush header
+			$this->flushFileHeader();
+
+			// Seek to old position
+			$this->seekToOldPosition();
+		} // END - if
+
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
+	}
+
+	/**
+	 * Marks the currently loaded block as empty (with length of the block)
+	 *
+	 * @param	$length		Length of the block
+	 * @return	void
+	 */
+	protected function markCurrentBlockAsEmpty ($length) {
+		// Get current seek position
+		$currentPosition = $this->key();
+
+		// Now add it as gap entry
+		array_push($this->gaps, array(
+			self::GAPS_INDEX_START  => ($currentPosition - $length),
+			self::GAPS_INDEX_END    => $currentPosition,
+		));
+	}
+
+	/**
+	 * Checks whether the file header is initialized
+	 *
+	 * @return	$isInitialized	Whether the file header is initialized
+	 */
+	public function isFileHeaderInitialized () {
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
+
+		// Default is not initialized
+		$isInitialized = FALSE;
+
+		// Is the file initialized?
+		if ($this->isFileInitialized()) {
+			// Some bytes has been written, so rewind to start of it.
+			$rewindStatus = $this->rewind();
+			//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] rewindStatus=%s', __METHOD__, __LINE__, $rewindStatus));
+
+			// Is the rewind() call successfull?
+			if ($rewindStatus != 1) {
+				// Something bad happened
+				self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Could not rewind().', __METHOD__, __LINE__));
+			} // END - if
+
+			// Read file header
+			$this->readFileHeader();
+
+			// The above method does already check the header
+			$isInitialized = TRUE;
+		} // END - if
+
+		// Return result
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] isInitialized=%d - EXIT!', __METHOD__, __LINE__, intval($isInitialized)));
+		return $isInitialized;
+	}
+
+	/**
+	 * Checks whether the assigned file has been initialized
+	 *
+	 * @return	$isInitialized		Whether the file's size is zero
+	 */
+	public function isFileInitialized () {
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
+
+		// Get it from iterator which holds the pointer instance. If FALSE is returned
+		$fileSize = $this->size();
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] fileSize=%s', __METHOD__, __LINE__, $fileSize));
+
+		/*
+		 * The returned file size should not be FALSE or NULL as this means
+		 * that the pointer class does not work correctly.
+		 */
+		assert(is_int($fileSize));
+
+		// Is more than 0 returned?
+		$isInitialized = ($fileSize > 0);
+
+		// Return result
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] isInitialized=%d - EXIT!', __METHOD__, __LINE__, intval($isInitialized)));
+		return $isInitialized;
+	}
+
+	/**
+	 * Creates the assigned file
+	 *
+	 * @return	void
+	 */
+	public function createFileHeader () {
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
+
+		// The file's header should not be initialized here
+		assert(!$this->isFileHeaderInitialized());
+
+		// Simple flush file header which will create it.
+		$this->flushFileHeader();
+
+		// Rewind seek position (to beginning of file) and update/flush file header
+		$this->rewindUpdateSeekPosition();
+
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!!', __METHOD__, __LINE__));
+	}
+
+	/**
+	 * Pre-allocates file (if enabled) with some space for later faster write access.
+	 *
+	 * @param	$type	Type of the file
+	 * @return	void
+	 */
+	public function preAllocateFile ($type) {
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
+
+		// Is it enabled?
+		if ($this->getConfigInstance()->getConfigEntry($type . '_pre_allocate_enabled') != 'Y') {
+			// Not enabled
+			self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Not pre-allocating file.', __METHOD__, __LINE__));
+
+			// Don't continue here.
+			return;
+		} // END - if
+
+		// Message to user
+		self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Pre-allocating file ...', __METHOD__, __LINE__));
+
+		// Calculate minimum length for one entry
+		$minLengthEntry = $this->getBlockInstance()->calculateMinimumBlockLength();
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] minLengthEntry=%s', __METHOD__, __LINE__, $minLengthEntry));
+
+		// Calulcate seek position
+		$seekPosition = $minLengthEntry * $this->getConfigInstance()->getConfigEntry($type . '_pre_allocate_count');
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] seekPosition=%s', __METHOD__, __LINE__, $seekPosition));
+
+		// Now simply write a NUL there. This will pre-allocate the file.
+		$this->writeData($seekPosition, chr(0));
+
+		// Rewind seek position (to beginning of file) and update/flush file header
+		$this->rewindUpdateSeekPosition();
+
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
+	}
+
+	/**
+	 * Close a file source and set it's instance to null and the file name
+	 * to empty
+	 *
+	 * @return	void
+	 * @todo	~10% done?
+	 */
+	public function closeFile () {
+		$this->partialStub('Unfinished method.');
+
+		// Remove file name
+		$this->setFileName('');
+	}
+
 	/**
 	 * Determines seek position
 	 *
 	 * @return	$seekPosition	Current seek position
-	 * @todo	0% done
 	 */
-	public final function determineSeekPosition () {
-		$this->partialStub('Unfinished method.');
+	public function determineSeekPosition () {
+		// Call pointer instance
+		return $this->getPointerInstance()->determineSeekPosition();
 	}
 
 	/**
@@ -101,10 +629,10 @@ class BaseFile extends BaseFrameworkSystem {
 	 * @param	$offset		Offset to seek to (or used as "base" for other seeks)
 	 * @param	$whence		Added to offset (default: only use offset to seek to)
 	 * @return	$status		Status of file seek: 0 = success, -1 = failed
-	 * @todo	0% done
 	 */
 	public function seek ($offset, $whence = SEEK_SET) {
-		$this->partialStub('Unfinished method.');
+		// Call pointer instance
+		return $this->getPointerInstance()->seek($offset, $whence);
 	}
 
 	/**
@@ -112,10 +640,261 @@ class BaseFile extends BaseFrameworkSystem {
 	 *
 	 * @return	$size	Size (in bytes) of file
 	 * @todo	Handle seekStatus
-	 * @todo	0% done
 	 */
 	public function size () {
-		$this->partialStub('Unfinished method.');
+		// Call pointer instance
+		return $this->getPointerInstance()->size();
+	}
+
+	/**
+	 * Read data a file pointer
+	 *
+	 * @return	mixed	The result of fread()
+	 * @throws	NullPointerException	If the file pointer instance
+	 *									is not set by setPointer()
+	 * @throws	InvalidResourceException	If there is being set
+	 */
+	public function readFromFile () {
+		// Call pointer instance
+		return $this->getPointerInstance()->readFromFile();
+	}
+
+	/**
+	 * Reads given amount of bytes from file.
+	 *
+	 * @param	$bytes	Amount of bytes to read
+	 * @return	$data	Data read from file
+	 */
+	public function read ($bytes) {
+		// Call pointer instance
+		return $this->getPointerInstance()->read($bytes);
+	}
+
+	/**
+	 * Write data to a file pointer
+	 *
+	 * @param	$dataStream		The data stream we shall write to the file
+	 * @return	mixed			Number of writes bytes or FALSE on error
+	 * @throws	NullPointerException	If the file pointer instance
+	 *									is not set by setPointer()
+	 * @throws	InvalidResourceException	If there is being set
+	 *											an invalid file resource
+	 */
+	public function writeToFile ($dataStream) {
+		// Call pointer instance
+		return $this->getPointerInstance()->writeToFile($dataStream);
+	}
+
+	/**
+	 * Rewinds to the beginning of the file
+	 *
+	 * @return	$status 	Status of this operation
+	 */
+	public function rewind () {
+		// Call pointer instance
+		return $this->getPointerInstance()->rewind();
+	}
+
+	/**
+	 * Determines whether the EOF has been reached
+	 *
+	 * @return	$isEndOfFileReached		Whether the EOF has been reached
+	 */
+	public final function isEndOfFileReached () {
+		// Call pointer instance
+		return $this->getPointerInstance()->isEndOfFileReached();
+	}
+
+	/**
+	 * Analyzes entries in index file. This will count all found (and valid)
+	 * entries, mark invalid as damaged and count gaps ("fragmentation"). If
+	 * only gaps are found, the file is considered as "virgin" (no entries).
+	 *
+	 * @return	void
+	 */
+	public function analyzeFile () {
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
+
+		// Make sure the file is initialized
+		assert($this->isFileInitialized());
+
+		// Init counters and gaps array
+		$this->initCountersGapsArray();
+
+		// Output message (as this may take some time)
+		self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Analyzing file structure ... (this may take some time)', __METHOD__, __LINE__));
+
+		// First rewind to the begining
+		$this->rewind();
+
+		// Then try to load all entries
+		while ($this->valid()) {
+			// Go to next entry
+			$this->next();
+
+			// Get current entry
+			$current = $this->getCurrentBlock();
+
+			// Debug message
+			/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] current()=%s', __METHOD__, __LINE__, strlen($current)));
+		} // END - while
+
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
+	}
+
+	/**
+	 * Advances to next "block" of bytes
+	 *
+	 * @return	void
+	 */
+	public function next () {
+		// Is there nothing to read?
+		if (!$this->valid()) {
+			// Nothing to read
+			return;
+		} // END - if
+
+		// Make sure the block instance is set
+		assert($this->getBlockInstance() instanceof CalculatableBlock);
+
+		// First calculate minimum block length
+		$length = $this->getBlockInstance()->calculateMinimumBlockLength();
+
+		// Short be more than zero!
+		assert($length > 0);
+
+		// Read possibly back-buffered bytes from previous call of next().
+		$data = $this->getBackBuffer();
+
+		/*
+		 * Read until a entry/block separator has been found. The next read
+		 * "block" may not fit, so this loop will continue until the EOB or EOF
+		 * has been reached whatever comes first.
+		 */
+		while ((!$this->isEndOfFileReached()) && (!self::isBlockSeparatorFound($data))) {
+			// Then read the next possible block
+			$block = $this->read($length);
+
+			// Is it all empty?
+			if (strlen(trim($block)) == 0) {
+				// Mark this block as empty
+				$this->markCurrentBlockAsEmpty($length);
+
+				// Skip to next block
+				continue;
+			} // END - if
+
+			// At this block then
+			$data .= $block;
+
+			// A debug message
+			//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d] data()=%s', __FUNCTION__, __LINE__, strlen($data)));
+		} // END - if
+
+		// EOF reached?
+		if ($this->isEndOfFileReached()) {
+			// Set whole data as current read block
+			//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('Calling setCurrentBlock(' . strlen($data) . ') ...');
+			$this->setCurrentBlock($data);
+
+			// Then abort here silently
+			//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('EOF reached.');
+			return;
+		} // END - if
+
+		/*
+		 * Init back-buffer which is the data that has been found beyond the
+		 * separator.
+		 */
+		$this->initBackBuffer();
+
+		// Separate data
+		$dataArray = explode(chr(self::SEPARATOR_ENTRIES), $data);
+
+		// This array must contain two elements
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('dataArray=' . print_r($dataArray, TRUE));
+		assert(count($dataArray) == 2);
+
+		// Left part is the actual block, right one the back-buffer data
+		$this->setCurrentBlock($dataArray[0]);
+		$this->setBackBuffer($dataArray[1]);
+	}
+
+	/**
+	 * Checks wether the current entry is valid (not at the end of the file).
+	 * This method will return TRUE if an emptied (nulled) entry has been found.
+	 *
+	 * @return	$isValid	Whether the next entry is valid
+	 */
+	public function valid () {
+		// Make sure the block instance is set
+		assert($this->getBlockInstance() instanceof Block);
+
+		// First calculate minimum block length
+		$length = $this->getBlockInstance()->calculateMinimumBlockLength();
+
+		// Short be more than zero!
+		assert($length > 0);
+
+		// Get current seek position
+		$seekPosition = $this->key();
+
+		// Then try to read it
+		$data = $this->read($length);
+
+		// If some bytes could be read, all is fine
+		$isValid = ((is_string($data)) && (strlen($data) > 0));
+
+		// Get header size
+		$headerSize = $this->getBlockInstance()->getHeaderSize();
+
+		// Is the seek position at or beyond the header?
+		if ($seekPosition >= $headerSize) {
+			// Seek back to old position
+			$this->seek($seekPosition);
+		} else {
+			// Seek directly behind the header
+			$this->seek($headerSize);
+		}
+
+		// Return result
+		return $isValid;
+	}
+
+	/**
+	 * Gets current seek position ("key").
+	 *
+	 * @return	$key	Current key in iteration
+	 */
+	public function key () {
+		// Call pointer instance
+		return $this->getPointerInstance()->determineSeekPosition();
+	}
+
+	/**
+	 * Reads the file header
+	 *
+	 * @return	void
+	 */
+	public function readFileHeader () {
+		// Make sure the block instance is set
+		assert($this->getBlockInstance() instanceof Block);
+
+		// Call block instance
+		$this->getBlockInstance()->readFileHeader();
+	}
+
+	/**
+	 * Flushes the file header
+	 *
+	 * @return	void
+	 */
+	public function flushFileHeader () {
+		// Make sure the block instance is set
+		assert($this->getBlockInstance() instanceof Block);
+
+		// Call block instance
+		$this->getBlockInstance()->flushFileHeader();
 	}
 }