X-Git-Url: https://git.mxchange.org/?p=core.git;a=blobdiff_plain;f=inc%2Fclasses%2Fmain%2Fstacker%2Ffile%2Fclass_BaseFileStack.php;h=e3aeb4701fb9c3f192b7fa9cec788448e13cfb61;hp=70bd7006f5c1c345e273f59790c256470af3a0f8;hb=c45d7623843f265ad3b2cf83a15444188cb8fb5a;hpb=79968ab0f673b50f09f35aed9bdc8112558e1553

diff --git a/inc/classes/main/stacker/file/class_BaseFileStack.php b/inc/classes/main/stacker/file/class_BaseFileStack.php
index 70bd7006..e3aeb470 100644
--- a/inc/classes/main/stacker/file/class_BaseFileStack.php
+++ b/inc/classes/main/stacker/file/class_BaseFileStack.php
@@ -28,29 +28,34 @@ class BaseFileStack extends BaseStacker {
 	const STACK_MAGIC = 'STACKv0.1';
 
 	/**
-	 * Separator magic->count
+	 * Separator for header data
 	 */
-	const SEPARATOR_MAGIC_COUNT = 0x00;
+	const SEPARATOR_HEADER_DATA = 0x01;
 
 	/**
-	 * Separator position->entries
+	 * Separator header->entries
 	 */
-	const SEPARATOR_SEEK_POS_ENTRIES = 0xff;
+	const SEPARATOR_HEADER_ENTRIES = 0x02;
 
 	/**
 	 * Separator hash->name
 	 */
-	const SEPARATOR_HASH_NAME = 0x05;
+	const SEPARATOR_HASH_NAME = 0x03;
+
+	/**
+	 * Length of name
+	 */
+	const LENGTH_NAME = 10;
 
 	/**
 	 * Length of count
 	 */
-	const COUNT_LENGTH = 20;
+	const LENGTH_COUNT = 20;
 
 	/**
 	 * Length of position
 	 */
-	const COUNT_POSITION = 20;
+	const LENGTH_POSITION = 20;
 
 	/**
 	 * Counter for total entries
@@ -62,6 +67,26 @@ class BaseFileStack extends BaseStacker {
 	 */
 	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 $damagedEntries = array();
+
 	/**
 	 * Protected constructor
 	 *
@@ -71,6 +96,37 @@ class BaseFileStack extends BaseStacker {
 	protected function __construct ($className) {
 		// Call parent constructor
 		parent::__construct($className);
+
+		// Calculate header size
+		$this->headerSize = (
+			strlen(self::STACK_MAGIC) +
+			strlen(self::SEPARATOR_HEADER_DATA) +
+			self::LENGTH_COUNT +
+			strlen(self::SEPARATOR_HEADER_DATA) +
+			self::LENGTH_POSITION +
+			strlen(self::SEPARATOR_HEADER_ENTRIES)
+		);
+
+		// Init counters and gaps array
+		$this->initCountersGapsArray();
+	}
+
+	/**
+	 * 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
+	 * analyzeStackFile() instead of this method.
+	 *
+	 * @return	void
+	 */
+	private function initCountersGapsArray () {
+		// Init counter and seek position
+		$this->setCounter(0);
+		$this->setSeekPosition(0);
+
+		// Init arrays
+		$this->gaps = array();
+		$this->damagedEntries = array();
 	}
 
 	/**
@@ -78,17 +134,28 @@ class BaseFileStack extends BaseStacker {
 	 *
 	 * @return	$totalEntries	Total entries in this stack
 	 */
-	private function getCounter () {
+	private final function getCounter () {
 		// Get it
 		return $this->totalEntries;
 	}
 
+	/**
+	 * Setter for total entries
+	 *
+	 * @param	$totalEntries	Total entries in this stack
+	 * @return	void
+	 */
+	private final function setCounter ($counter) {
+		// Set it
+		$this->totalEntries = $counter;
+	}
+
 	/**
 	 * Increment counter
 	 *
 	 * @return	void
 	 */
-	private function incrementCounter () {
+	private final function incrementCounter () {
 		// Get it
 		$this->totalEntries++;
 	}
@@ -98,7 +165,7 @@ class BaseFileStack extends BaseStacker {
 	 *
 	 * @return	$seekPosition	Current seek position (stored here in object)
 	 */
-	private function getSeekPosition () {
+	private final function getSeekPosition () {
 		// Get it
 		return $this->seekPosition;
 	}
@@ -109,7 +176,7 @@ class BaseFileStack extends BaseStacker {
 	 * @param	$seekPosition	Current seek position (stored here in object)
 	 * @return	void
 	 */
-	private function setSeekPosition ($seekPosition) {
+	private final function setSeekPosition ($seekPosition) {
 		// And set it
 		$this->seekPosition = $seekPosition;
 	}
@@ -120,11 +187,77 @@ class BaseFileStack extends BaseStacker {
 	 * @return	void
 	 */
 	private function updateSeekPosition () {
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
+
 		// Get key (= seek position)
 		$seekPosition = $this->getIteratorInstance()->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__));
+	}
+
+	/**
+	 * Reads the file header
+	 *
+	 * @return	void
+	 */
+	private function readFileHeader () {
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
+
+		// First rewind to beginning as the header sits at the beginning ...
+		$this->getIteratorInstance()->rewind();
+
+		// Then read it (see constructor for calculation)
+		$data = $this->getIteratorInstance()->read($this->headerSize);
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Read %d bytes (%d wanted).', __METHOD__, __LINE__, strlen($data), $this->headerSize));
+
+		// Have all requested bytes been read?
+		assert(strlen($data) == $this->headerSize);
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
+
+		// Last character must be the separator
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] data(-1)=%s', __METHOD__, __LINE__, dechex(ord(substr($data, -1, 1)))));
+		assert(substr($data, -1, 1) == chr(self::SEPARATOR_HEADER_ENTRIES));
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
+
+		// Okay, then remove it
+		$data = substr($data, 0, -1);
+
+		// And update seek position
+		$this->updateSeekPosition();
+
+		/*
+		 * Now split it:
+		 *
+		 * 0 => Magic
+		 * 1 => Total entries
+		 * 2 => Current seek position
+		 */
+		$this->header = explode(chr(self::SEPARATOR_HEADER_DATA), $data);
+
+		// Check if the array has only 3 elements
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] header(%d)=%s', __METHOD__, __LINE__, count($this->header), print_r($this->header, TRUE)));
+		assert(count($this->header) == 3);
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
+
+		// Check magic
+		assert($this->header[0] == self::STACK_MAGIC);
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
+
+		// Check length of count and seek position
+		assert(strlen($this->header[1]) == self::LENGTH_COUNT);
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
+		assert(strlen($this->header[2]) == self::LENGTH_POSITION);
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
+
+		// Decode count and seek position
+		$this->header[1] = hex2bin($this->header[1]);
+		$this->header[2] = hex2bin($this->header[2]);
+
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
 	}
 
 	/**
@@ -133,19 +266,31 @@ class BaseFileStack extends BaseStacker {
 	 * @return	$isInitialized	Whether the file header is initialized
 	 */
 	private 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.
-			$this->getIteratorInstance()->rewind();
+			$rewindStatus = $this->getIteratorInstance()->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;
 	}
 
@@ -155,11 +300,11 @@ class BaseFileStack extends BaseStacker {
 	 * @return	$isInitialized		Whether the file's size is zero
 	 */
 	private function isFileInitialized () {
-		// Default is not initialized
-		$isInitialized = FALSE;
+		//* 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->getIteratorInstance()->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
@@ -168,12 +313,10 @@ class BaseFileStack extends BaseStacker {
 		assert(is_int($fileSize));
 
 		// Is more than 0 returned?
-		if ($fileSize > 0) {
-			// So is the header written?
-			$isInitialized = $this->getIteratorInstance()->isHeaderInitialized();
-		} // END - if
+		$isInitialized = ($fileSize > 0);
 
 		// Return result
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] isInitialized=%d - EXIT!', __METHOD__, __LINE__, intval($isInitialized)));
 		return $isInitialized;
 	}
 
@@ -183,11 +326,14 @@ class BaseFileStack extends BaseStacker {
 	 * @return	void
 	 */
 	private 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());
 
-		// Flush file header
+		// Simple flush file header which will create it.
 		$this->flushFileHeader();
+
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!!', __METHOD__, __LINE__));
 	}
 
 	/**
@@ -196,39 +342,122 @@ class BaseFileStack extends BaseStacker {
 	 * @return	void
 	 */
 	private function flushFileHeader () {
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
+
 		// Put all informations together
-		$header = sprintf('%s%s%s%s%s',
+		$header = sprintf('%s%s%s%s%s%s',
 			// Magic
 			self::STACK_MAGIC,
 
 			// Separator magic<->count
-			chr(self::SEPARATOR_MAGIC_COUNT),
+			chr(self::SEPARATOR_HEADER_DATA),
 
 			// Total entries (will be zero) and pad it to 20 chars
-			str_pad($this->dec2hex($this->getCounter()), self::COUNT_LENGTH, '0', STR_PAD_LEFT),
+			str_pad($this->dec2hex($this->getCounter()), self::LENGTH_COUNT, '0', STR_PAD_LEFT),
+
+			// Separator count<->seek position
+			chr(self::SEPARATOR_HEADER_DATA),
 
 			// Position (will be zero)
-			str_pad($this->dec2hex(0, 2), self::COUNT_POSITION, '0', STR_PAD_LEFT),
+			str_pad($this->dec2hex($this->getSeekPosition(), 2), self::LENGTH_POSITION, '0', STR_PAD_LEFT),
 
 			// Separator position<->entries
-			chr(self::SEPARATOR_SEEK_POS_ENTRIES)
+			chr(self::SEPARATOR_HEADER_ENTRIES)
 		);
 
 		// Write it to disk (header is always at seek position 0)
-		$this->getIteratorInstance()->writeAtPosition(0, $header);
+		$this->writeData(0, $header);
+
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
+	}
+
+	/**
+	 * Writes data at given position
+	 *
+	 * @param	$seekPosition	Seek position
+	 * @param	$data			Data to be written
+	 * @return	void
+	 */
+	private function writeData ($seekPosition, $data) {
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] seekPosition=%s,data()=%s - CALLED!', __METHOD__, __LINE__, $seekPosition, strlen($data)));
+
+		// Write data at given position
+		$this->getIteratorInstance()->writeAtPosition($seekPosition, $data);
 
 		// Update seek position
 		$this->updateSeekPosition();
+
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
+	}
+
+	/**
+	 * Pre-allocates file (if enabled) with some space for later faster write access.
+	 *
+	 * @return	void
+	 */
+	private function preAllocateFile () {
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
+
+		// Is it enabled?
+		if ($this->getConfigInstance()->getConfigEntry('file_stack_pre_allocate_enabled') != 'Y') {
+			// Not enabled
+			self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Not pre-allocating stack file.', __METHOD__, __LINE__));
+
+			// Don't continue here.
+			return;
+		} // END - if
+
+		// Message to user
+		self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Pre-allocating stack file ...', __METHOD__, __LINE__));
+
+		/*
+		 * Calculate minimum length for one entry:
+		 * minimum length = hash length + separator + name + minimum entry size = ?? + 1 + 10 + 1 = ??
+		 */
+		$minLengthEntry = self::getHashLength() + strlen(self::SEPARATOR_HASH_NAME) + self::LENGTH_NAME + 1;
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] minLengthEntry=%s', __METHOD__, __LINE__, $minLengthEntry));
+
+		// Calulcate seek position
+		$seekPosition = $minLengthEntry * $this->getConfigInstance()->getConfigEntry('file_stack_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));
+
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
+	}
+
+	/**
+	 * Analyzes entries in stack 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
+	 */
+	private function analyzeStackFile () {
+		//* 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__));
+
+		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
 	}
 
 	/**
 	 * Initializes this file-based stack.
 	 *
 	 * @param	$fileName	File name of this stack
+	 * @param	$type		Type of this stack (e.g. url_source for URL sources)
 	 * @return	void
 	 */
-	protected function initFileStack ($fileName) {
-		// Get a file i/o pointer instance
+	protected function initFileStack ($fileName, $type) {
+		// Get a file i/o pointer instance for stack file
 		$pointerInstance = ObjectFactory::createObjectByConfiguredName('file_raw_input_output_class', array($fileName));
 
 		// Get iterator instance
@@ -241,72 +470,28 @@ class BaseFileStack extends BaseStacker {
 		$this->setIteratorInstance($iteratorInstance);
 
 		// Is the file's header initialized?
-		if ($this->isFileHeaderInitialized()) {
-			// Then load it
-			$this->loadFileHeader();
-		} else {
+		if (!$this->isFileHeaderInitialized()) {
 			// No, then create it (which may pre-allocate the stack)
 			$this->createFileHeader();
 
 			// And pre-allocate a bit
 			$this->preAllocateFile();
-		}
-	}
-
-	/**
-	 * Initializes given stacker
-	 *
-	 * @param	$stackerName	Name of the stack
-	 * @param	$forceReInit	Force re-initialization
-	 * @return	void
-	 * @throws	AlreadyInitializedStackerException	If the stack is already initialized
-	 */
-	public function initStack ($stackerName, $forceReInit = FALSE) {
-		// Is the stack already initialized?
-		if (($forceReInit === FALSE) && ($this->isStackInitialized($stackerName))) {
-			// Then throw the exception
-			throw new AlreadyInitializedStackerException(array($this, $stackerName, $forceReInit), self::EXCEPTION_STACKER_ALREADY_INITIALIZED);
 		} // END - if
 
-		// Initialize the given stack
-		$this->partialStub('stackerName=' . $stackerName . ',forceReInit=' . intval($forceReInit));
-	}
+		// Load the file header
+		$this->readFileHeader();
 
-	/**
-	 * Checks whether the given stack is initialized (set in array $stackers)
-	 *
-	 * @param	$stackerName	Name of the stack
-	 * @return	$isInitialized	Whether the stack is initialized
-	 */
-	public function isStackInitialized ($stackerName) {
-		// Is is there?
-		$this->partialStub('stackerName=' . $stackerName);
-		$isInitialized = TRUE;
-
-		// Return result
-		return $isInitialized;
-	}
-
-	/**
-	 * Getter for size of given stack (array count)
-	 *
-	 * @param	$stackerName	Name of the stack
-	 * @return	$count			Size of stack (array count)
-	 * @throws	NoStackerException	If given stack is missing
-	 */
-	public function getStackCount ($stackerName) {
-		// Is the stack not yet initialized?
-		if (!$this->isStackInitialized($stackerName)) {
-			// Throw an exception
-			throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
-		} // END - if
+		// Count all entries in file
+		$this->analyzeStackFile();
 
-		// Now, count the array of entries
-		$this->partialStub('stackerName=' . $stackerName);
-		$count = 0;
+		/*
+		 * Get stack index instance. This can be used for faster
+		 * "defragmentation" and startup.
+		 */
+		$indexInstance = FileStackIndexFactory::createFileStackIndexInstance($fileName, $type);
 
-		// Return result
-		return $count;
+		// And set it here
+		$this->setIndexInstance($indexInstance);
 	}
 
 	/**
@@ -315,17 +500,14 @@ class BaseFileStack extends BaseStacker {
 	 * @param	$stackerName	Name of the stack
 	 * @param	$value			Value to add to this stacker
 	 * @return	void
-	 * @throws	FullStackerException	Thrown if the stack is full
+	 * @throws	FullStackerException	If the stack is full
 	 */
 	protected function addValue ($stackerName, $value) {
-		// Is the stack not yet initialized or full?
-		if (!$this->isStackInitialized($stackerName)) {
-			// Then do it here
-			$this->initStack($stackerName);
-		} elseif ($this->isStackFull($stackerName)) {
+		// Do some tests
+		if ($this->isStackFull($stackerName)) {
 			// Stacker is full
 			throw new FullStackerException(array($this, $stackerName, $value), self::EXCEPTION_STACKER_IS_FULL);
-		}
+		} // END - if
 
 		// Now add the value to the stack
 		$this->partialStub('stackerName=' . $stackerName . ',value[]=' . gettype($value));
@@ -336,18 +518,14 @@ class BaseFileStack extends BaseStacker {
 	 *
 	 * @param	$stackerName	Name of the stack
 	 * @return	$value			Value of last added value
-	 * @throws	NoStackerException	If the named stacker was not found
-	 * @throws	EmptyStackerException	If the named stacker is empty
+	 * @throws	EmptyStackerException	If the stack is empty
 	 */
 	protected function getLastValue ($stackerName) {
 		// Is the stack not yet initialized or full?
-		if (!$this->isStackInitialized($stackerName)) {
-			// Throw an exception
-			throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
-		} elseif ($this->isStackEmpty($stackerName)) {
+		if ($this->isStackEmpty($stackerName)) {
 			// Throw an exception
 			throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
-		}
+		} // END - if
 
 		// Now get the last value
 		$this->partialStub('stackerName=' . $stackerName);
@@ -362,18 +540,14 @@ class BaseFileStack extends BaseStacker {
 	 *
 	 * @param	$stackerName	Name of the stack
 	 * @return	$value			Value of last added value
-	 * @throws	NoStackerException	If the named stacker was not found
-	 * @throws	EmptyStackerException	If the named stacker is empty
+	 * @throws	EmptyStackerException	If the stack is empty
 	 */
 	protected function getFirstValue ($stackerName) {
 		// Is the stack not yet initialized or full?
-		if (!$this->isStackInitialized($stackerName)) {
-			// Throw an exception
-			throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
-		} elseif ($this->isStackEmpty($stackerName)) {
+		if ($this->isStackEmpty($stackerName)) {
 			// Throw an exception
 			throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
-		}
+		} // END - if
 
 		// Now get the first value
 		$this->partialStub('stackerName=' . $stackerName);
@@ -388,18 +562,14 @@ class BaseFileStack extends BaseStacker {
 	 *
 	 * @param	$stackerName	Name of the stack
 	 * @return	$value			Value "poped" from array
-	 * @throws	NoStackerException	If the named stacker was not found
-	 * @throws	EmptyStackerException	If the named stacker is empty
+	 * @throws	EmptyStackerException	If the stack is empty
 	 */
 	protected function popLast ($stackerName) {
 		// Is the stack not yet initialized or full?
-		if (!$this->isStackInitialized($stackerName)) {
-			// Throw an exception
-			throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
-		} elseif ($this->isStackEmpty($stackerName)) {
+		if ($this->isStackEmpty($stackerName)) {
 			// Throw an exception
 			throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
-		}
+		} // END - if
 
 		// Now, remove the last entry, we don't care about the return value here, see elseif() block above
 		$this->partialStub('stackerName=' . $stackerName);
@@ -411,23 +581,93 @@ class BaseFileStack extends BaseStacker {
 	 *
 	 * @param	$stackerName	Name of the stack
 	 * @return	$value			Value "shifted" from array
-	 * @throws	NoStackerException	If the named stacker was not found
 	 * @throws	EmptyStackerException	If the named stacker is empty
 	 */
 	protected function popFirst ($stackerName) {
 		// Is the stack not yet initialized or full?
-		if (!$this->isStackInitialized($stackerName)) {
-			// Throw an exception
-			throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
-		} elseif ($this->isStackEmpty($stackerName)) {
+		if ($this->isStackEmpty($stackerName)) {
 			// Throw an exception
 			throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
-		}
+		} // END - if
 
 		// Now, remove the last entry, we don't care about the return value here, see elseif() block above
 		$this->partialStub('stackerName=' . $stackerName);
 		return NULL;
 	}
+
+	/**
+	 * Checks whether the given stack is full
+	 *
+	 * @param	$stackerName	Name of the stack
+	 * @return	$isFull			Whether the stack is full
+	 */
+	protected function isStackFull ($stackerName) {
+		// File-based stacks will only run full if the disk space is low.
+		// @TODO Please implement this, returning FALSE
+		$isFull = FALSE;
+
+		// Return result
+		return $isFull;
+	}
+
+	/**
+	 * Checks whether the given stack is empty
+	 *
+	 * @param	$stackerName		Name of the stack
+	 * @return	$isEmpty			Whether the stack is empty
+	 * @throws	NoStackerException	If given stack is missing
+	 */
+	public function isStackEmpty ($stackerName) {
+		// So, is the stack empty?
+		$isEmpty = (($this->getStackCount($stackerName)) == 0);
+
+		// Return result
+		return $isEmpty;
+	}
+
+	/**
+	 * Initializes given stacker
+	 *
+	 * @param	$stackerName	Name of the stack
+	 * @param	$forceReInit	Force re-initialization
+	 * @return	void
+	 * @throws	UnsupportedOperationException	This method is not (and maybe never will be) supported
+	 */
+	public function initStack ($stackerName, $forceReInit = FALSE) {
+		throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
+	}
+
+	/**
+	 * Initializes all stacks
+	 *
+	 * @return	void
+	 * @throws	UnsupportedOperationException	This method is not (and maybe never will be) supported
+	 */
+	public function initStacks (array $stacks, $forceReInit = FALSE) {
+		throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
+	}
+
+	/**
+	 * Checks whether the given stack is initialized (set in array $stackers)
+	 *
+	 * @param	$stackerName	Name of the stack
+	 * @return	$isInitialized	Whether the stack is initialized
+	 * @throws	UnsupportedOperationException	This method is not (and maybe never will be) supported
+	 */
+	public function isStackInitialized ($stackerName) {
+		throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
+	}
+
+	/**
+	 * Getter for size of given stack (array count)
+	 *
+	 * @param	$stackerName	Name of the stack
+	 * @return	$count			Size of stack (array count)
+	 */
+	public function getStackCount ($stackerName) {
+		// Now, simply return the found count value, this must be up-to-date then!
+		return $this->getCounter();
+	}
 }
 
 // [EOF]