From: Roland Häder <roland@mxchange.org>
Date: Mon, 7 Dec 2020 14:16:48 +0000 (+0100)
Subject: Rewrites:
X-Git-Url: https://git.mxchange.org/?a=commitdiff_plain;h=fc83e6b1ac6fe3a5e09a3e4f8bad20fa2240cae4;p=core.git

Rewrites:
- more thrown exceptions
- more debug logging (currently messing up phpunit output)
- more type-hints for primitive variables added
- writeAtPosition() must be used instead of writeData() as the later one
  increments the counter
- debug log files could contain non-text data, so let's treat them as as text
  anyway ...

Signed-off-by: Roland Häder <roland@mxchange.org>
---

diff --git a/contrib/missing-methods.sh b/contrib/missing-methods.sh
index 6c7ac041..91dc1241 100755
--- a/contrib/missing-methods.sh
+++ b/contrib/missing-methods.sh
@@ -13,4 +13,4 @@ then
 	exit 255
 fi
 
-grep __call "${DEBUG_FILE}" | cut -d "[" -f 4 | cut -d "]" -f 1
+grep -a __call "${DEBUG_FILE}" | cut -d "[" -f 4 | cut -d "]" -f 1
diff --git a/framework/main/classes/database/result/class_CachedDatabaseResult.php b/framework/main/classes/database/result/class_CachedDatabaseResult.php
index 664270e6..74766038 100644
--- a/framework/main/classes/database/result/class_CachedDatabaseResult.php
+++ b/framework/main/classes/database/result/class_CachedDatabaseResult.php
@@ -174,7 +174,7 @@ class CachedDatabaseResult extends BaseDatabaseResult implements SearchableResul
 	 * @param	$index	Index to seek for
 	 * @return	void
 	 */
-	public function seek ($index) {
+	public function seek (int $index) {
 		// Rewind to beginning
 		$this->rewind();
 
diff --git a/framework/main/classes/file_directories/binary/class_BaseBinaryFile.php b/framework/main/classes/file_directories/binary/class_BaseBinaryFile.php
index 04e6da4e..187ac493 100644
--- a/framework/main/classes/file_directories/binary/class_BaseBinaryFile.php
+++ b/framework/main/classes/file_directories/binary/class_BaseBinaryFile.php
@@ -13,6 +13,7 @@ use Org\Mxchange\CoreFramework\Filesystem\File\BaseAbstractFile;
 use \BadMethodCallException;
 use \InvalidArgumentException;
 use \SplFileInfo;
+use \UnexpectedValueException;
 
 /**
  * A general binary file class
@@ -179,28 +180,20 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 	 * @return	$isGapsOnly		Whether the abstracted file only contains gaps
 	 */
 	private function isFileOnlyGaps () {
-		// First/last gap found?
-		/* Only for debugging
-		if (isset($this->gaps[0])) {
-			// Output first and last gap
-			self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] this->gaps[0]=%s,this->gaps[%s]=%s', print_r($this->gaps[0], true), (count($this->gaps) - 1), print_r($this->gaps[count($this->gaps) - 1], true)));
-		}
-		*/
-
-		// Now count every gap
+		// Count every gap
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: CALLED!');
 		$gapsSize = 0;
 		foreach ($this->gaps as $gap) {
 			// Calculate size of found gap: end-start including both
 			$gapsSize += ($gap[self::GAPS_INDEX_END] - $gap[self::GAPS_INDEX_START]);
 		}
 
-		// Debug output
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] gapsSize=%s,this->headerSize=%s', $gapsSize, $this->getHeaderSize()));
-
 		// Total gap size + header size must be same as file size
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: gapsSize=%s,this->headerSize=%s', $gapsSize, $this->getHeaderSize()));
 		$isGapsOnly = (($this->getHeaderSize() + $gapsSize) == $this->getFileSize());
 
 		// Return status
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: isGapsOnly=%d - EXIT!', intval($isGapsOnly)));
 		return $isGapsOnly;
 	}
 
@@ -213,13 +206,17 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 	 * @return	void
 	 */
 	public function initCountersGapsArray () {
-		// Init counter and seek position
+		// Init counter and seek position to header size
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: CALLED!');
 		$this->setCounter(0);
-		$this->setSeekPosition(0);
+		$this->setSeekPosition($this->getHeaderSize());
 
 		// Init arrays
 		$this->gaps = [];
 		$this->damagedEntries = [];
+
+		// Trace message
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: CALLED!');
 	}
 
 	/**
@@ -270,7 +267,7 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 	 * @return	$seekPosition	Current seek position (stored here in object)
 	 */
 	public final function getSeekPosition () {
-		// Get it
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: Getting this->seekPosition=%d - CALLED!', $this->seekPosition));
 		return $this->seekPosition;
 	}
 
@@ -281,7 +278,7 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 	 * @return	void
 	 */
 	protected final function setSeekPosition (int $seekPosition) {
-		// And set it
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: Setting seekPosition=%d - CALLED!', $seekPosition));
 		$this->seekPosition = $seekPosition;
 	}
 
@@ -291,40 +288,43 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 	 * @return	void
 	 */
 	public function updateSeekPosition () {
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] CALLED!'));
-
 		// Get key (= seek position)
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: CALLED!');
 		$seekPosition = $this->key();
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] Setting seekPosition=%s', $seekPosition));
 
 		// And set it here
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: seekPosition=%d', $seekPosition));
 		$this->setSeekPosition($seekPosition);
 
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] EXIT!'));
+		// Trace message
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: EXIT!');
 	}
 
 	/**
 	 * Seeks to beginning of file, updates seek position in this object and
 	 * flushes the header.
 	 *
+	 * @param	$flushHeader	Wether the file's header should be flushed (default: false)
 	 * @return	void
 	 */
-	protected function rewindUpdateSeekPosition () {
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] CALLED!'));
-
-		// flushFileHeader must be callable
-		assert(is_callable(array($this, 'flushFileHeader')));
-
+	protected function rewindUpdateSeekPosition (bool $flushHeader = false) {
 		// Seek to beginning of file
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: flushHeader=%d - CALLED!', intval($flushHeader)));
 		$this->rewind();
 
 		// And update seek position ...
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: Calling this->updateSeekPosition() ...');
 		$this->updateSeekPosition();
 
-		// ... to write it back into the file
-		$this->flushFileHeader();
+		// Flush headers?
+		if ($flushHeader) {
+			// ... to write it back into the file
+			/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: Calling this->flushFileHeader() ...');
+			$this->flushFileHeader();
+		}
 
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] EXIT!'));
+		// Trace message
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: EXIT!');
 	}
 
 	/**
@@ -333,12 +333,12 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 	 * @return	void
 	 */
 	protected function seekToOldPosition () {
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] CALLED!'));
-
 		// Seek to currently ("old") saved position
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: CALLED!');
 		$this->seek($this->getSeekPosition());
 
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] EXIT!'));
+		// Trace message
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: EXIT!');
 	}
 
 	/**
@@ -346,12 +346,21 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 	 *
 	 * @param	$str		String to look in
 	 * @return	$isFound	Whether the block separator has been found
+	 * @throws	InvalidArgumentException	If a parameter is not valid
 	 */
-	public static function isBlockSeparatorFound ($str) {
+	public static function isBlockSeparatorFound (string $str) {
+		// Validate parameter
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: str=%s - CALLED!', $str));
+		if (empty($str)) {
+			// Throw IAE
+			throw new InvalidArgumentException('Parameter "str" is empty');
+		}
+
 		// Determine it
 		$isFound = (strpos($str, chr(self::SEPARATOR_ENTRIES)) !== false);
 
 		// Return result
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: isFound=%d - EXIT!', intval($isFound)));
 		return $isFound;
 	}
 
@@ -362,7 +371,11 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 	 */
 	private function initBackBuffer () {
 		// Simply call the setter
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: CALLED!');
 		$this->setBackBuffer('');
+
+		// Trace message
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: EXIT!');
 	}
 
 	/**
@@ -388,7 +401,7 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 	/**
 	 * Setter for currentBlock field
 	 *
-	 * @param	$currentBlock		Characters to set a currently loaded block
+	 * @param	$currentBlock	Characters to set a currently loaded block
 	 * @return	void
 	 */
 	private function setCurrentBlock (string $currentBlock) {
@@ -446,20 +459,26 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 		}
 
 		// Write data at given position
-		$this->getPointerInstance()->writeAtPosition($seekPosition, $data);
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: Calling this->writeAtPosition(%d,%s) ...', $seekPosition, $data));
+		$this->writeAtPosition($seekPosition, $data);
 
 		// Increment counter
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: Calling this->incrementCounter() ...');
 		$this->incrementCounter();
 
 		// Update seek position
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: Calling this->updateSeekPosition() ...');
 		$this->updateSeekPosition();
 
 		// Flush the header?
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: flushHeader=%d', intval($flushHeader)));
 		if ($flushHeader === true) {
 			// Flush header
+			/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: Calling this->flushFileHeader() ...');
 			$this->flushFileHeader();
 
 			// Seek to old position
+			/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: Calling this->seekToOldPosition() ...');
 			$this->seekToOldPosition();
 		}
 
@@ -467,6 +486,34 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: EXIT!');
 	}
 
+	/**
+	 * Writes at given position by seeking to it.
+	 *
+	 * @param	$seekPosition	Seek position in file
+	 * @param	$dataStream		Data to be written
+	 * @return	mixed			Number of writes bytes or false on error
+	 * @throws	InvalidArgumentException	If a parameter is not valid
+	 */
+	public function writeAtPosition (int $seekPosition, string $dataStream) {
+		// Validate parameter
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: seekPosition=%d,dataStream(%d)=%s - CALLED!', $seekPosition, strlen($dataStream), $dataStream));
+		if ($seekPosition < 0) {
+			// Invalid seek position
+			throw new InvalidArgumentException(sprintf('seekPosition=%d is not valid.', $seekPosition));
+		} elseif (empty($dataStream)) {
+			// Empty dataStream
+			throw new InvalidArgumentException('Parameter "dataStream" is empty');
+		}
+
+		// Call pointer's method
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: Calling this->pointerInstance->writeAtPosition(%d, %s) ...', $seekPosition, $dataStream));
+		$status = $this->getPointerInstance()->writeAtPosition($seekPosition, $dataStream);
+
+		// Return status
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: status[%s]=%d - EXIT!', gettype($status), $status));
+		return $status;
+	}
+
 	/**
 	 * Marks the currently loaded block as empty (with length of the block)
 	 *
@@ -476,7 +523,7 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 	 */
 	protected function markCurrentBlockAsEmpty (int $length) {
 		// Validate parameter
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: length=%d - CALLED!', $length));
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: length=%d - CALLED!', $length));
 		if ($length < 1) {
 			// Length cannot below one
 			throw new InvalidArgumentException(sprintf('length=%d is not valid', $length));
@@ -492,7 +539,7 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 		));
 
 		// Trace message
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: EXIT!');
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: EXIT!');
 	}
 
 	/**
@@ -508,20 +555,18 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 		// Is the file initialized?
 		if ($this->isFileInitialized()) {
 			// Some bytes has been written, so rewind to start of it.
-			$rewindStatus = $this->rewind();
-
-			// Is the rewind() call successfull?
-			/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: rewindStatus=%d', $rewindStatus));
-			if ($rewindStatus != 1) {
-				// Something bad happened
-				self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: Could not rewind().');
-			}
+			$this->rewind();
 
 			// Read file header
+			/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: Calling this->readFileHeader() ...');
 			$this->readFileHeader();
 
+			// Get header count
+			$headerCount = count($this->getHeader());
+
 			// The above method does already check the header
-			$isInitialized = true;
+			/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: headerCount=%d', $headerCount));
+			$isInitialized = ($headerCount > 0);
 		}
 
 		// Return result
@@ -536,21 +581,21 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 	 */
 	public function isFileInitialized () {
 		// Get it from iterator which holds the pointer instance. If false is returned
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: CALLED!');
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: CALLED!');
 		$fileSize = $this->size();
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: fileSize=%s', $fileSize));
 
 		/*
 		 * The returned file size should not be false or NULL as this means
 		 * that the pointer class does not work correctly.
 		 */
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: fileSize[%s]=%d', gettype($fileSize), $fileSize));
 		assert(is_int($fileSize));
 
 		// Is more than 0 returned?
 		$isInitialized = ($fileSize > 0);
 
 		// Return result
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: isInitialized=%d - EXIT!', intval($isInitialized)));
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: isInitialized=%d - EXIT!', intval($isInitialized)));
 		return $isInitialized;
 	}
 
@@ -558,20 +603,27 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 	 * Creates the assigned file
 	 *
 	 * @return	void
+	 * @throws	BadMethodCallException	If this file's header is already initialized
 	 */
 	public function createFileHeader () {
 		// The file's header should not be initialized here
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: CALLED!');
-		assert(!$this->isFileHeaderInitialized());
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: CALLED!');
+		if ($this->isFileHeaderInitialized()) {
+			// Bad method call
+			//* DEBUG-DIE: */ die(sprintf('[%s:%d]: this=%s', __METHOD__, __LINE__, print_r($this, TRUE)));
+			throw new BadMethodCallException('File header is already initialized but method called');
+		}
 
 		// Simple flush file header which will create it.
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: Calling this->flushFileHeader() ...');
 		$this->flushFileHeader();
 
 		// Rewind seek position (to beginning of file) and update/flush file header
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: Calling this->rewindUpdateSeekPosition() ...');
 		$this->rewindUpdateSeekPosition();
 
 		// Trace message
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: EXIT!');
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: EXIT!');
 	}
 
 	/**
@@ -597,18 +649,18 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 		self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: Pre-allocating file ...');
 
 		// Calculate minimum length for one entry
-		$minLengthEntry = $this->getBlockInstance()->calculateMinimumBlockLength();
+		$minimumBlockLength = $this->getBlockInstance()->calculateMinimumBlockLength();
 
 		// Calulcate seek position
-		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: minLengthEntry=%s', $minLengthEntry));
-		$seekPosition = $minLengthEntry * FrameworkBootstrap::getConfigurationInstance()->getConfigEntry($type . '_pre_allocate_count');
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: minimumBlockLength=%s', $minimumBlockLength));
+		$seekPosition = $minimumBlockLength * FrameworkBootstrap::getConfigurationInstance()->getConfigEntry($type . '_pre_allocate_count');
 
 		// Now simply write a NUL there. This will pre-allocate the file.
-		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: seekPosition=%d', $seekPosition));
-		$this->writeData($seekPosition, chr(0));
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: Calling this->writeAtPosition(%d,NUL) ...', $seekPosition));
+		$this->writeAtPosition($seekPosition, chr(0));
 
-		// Rewind seek position (to beginning of file) and update/flush file header
-		$this->rewindUpdateSeekPosition();
+		// Rewind seek position
+		$this->rewind();
 
 		// Trace message
 		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: EXIT!');
@@ -631,7 +683,7 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 	 * @param	$whence		Added to offset (default: only use offset to seek to)
 	 * @return	$status		Status of file seek: 0 = success, -1 = failed
 	 */
-	public function seek (int $offset, $whence = SEEK_SET) {
+	public function seek (int $offset, int $whence = SEEK_SET) {
 		// Call pointer instance
 		return $this->getPointerInstance()->seek($offset, $whence);
 	}
@@ -667,7 +719,7 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 	 */
 	public function analyzeFile () {
 		// Make sure the file is initialized
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: CALLED!');
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: CALLED!');
 		if (!$this->isFileInitialized()) {
 			// Bad method call
 			throw new BadMethodCallException('Method called but file is not initialized.');
@@ -725,7 +777,7 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 				$this->doRunDefragmentation();
 			}
 		}
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: EXIT!');
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: EXIT!');
 	}
 
 	/**
@@ -736,16 +788,16 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 	 */
 	public function next () {
 		// Is there nothing to read?
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: CALLED!');
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: CALLED!');
 		if (!$this->valid()) {
 			// Nothing to read
 			return;
 		}
 
 		// First calculate minimum block length
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: key()=%d', $this->key()));
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: key()=%d', $this->key()));
 		$length = $this->getBlockInstance()->calculateMinimumBlockLength();
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: length=%s', $length));
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: length=%d', $length));
 
 		// Read possibly back-buffered bytes from previous call of next().
 		$data = $this->getBackBuffer();
@@ -755,20 +807,21 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 		 * "block" may not fit, so this loop will continue until the EOB or EOF
 		 * has been reached whatever comes first.
 		 */
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: data()=%d', strlen($data)));
-		while ((!$this->isEndOfFileReached()) && (!self::isBlockSeparatorFound($data))) {
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: data()=%d', strlen($data)));
+		while ((!$this->isEndOfFileReached()) && (empty($data) || !self::isBlockSeparatorFound($data))) {
 			// Then read the next possible block
+			/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: Calling this->read(%d) ...', $length));
 			$block = $this->read($length);
 
 			// Is it all empty?
-			//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: block()=%d,length=%s', strlen($block), $length));
-			if (strlen(trim($block)) == 0) {
+			/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: block()=%d,length=%s', strlen($block), $length));
+			if (strlen(trim($block, chr(0))) == 0) {
 				// Mark this block as empty
-				//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: Calling markCurrentBlockAsEmpty(%d) ...', strlen($block)));
+				/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: Calling markCurrentBlockAsEmpty(%d) ...', strlen($block)));
 				$this->markCurrentBlockAsEmpty(strlen($block));
 
 				// Skip to next block
-				//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: CONTINUE!');
+				/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: CONTINUE!');
 				continue;
 			}
 
@@ -776,17 +829,17 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 			$data .= $block;
 
 			// A debug message
-			//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: data()=%d', strlen($data)));
+			/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: data()=%d', strlen($data)));
 		}
 
 		// EOF reached?
 		if ($this->isEndOfFileReached()) {
 			// Set whole data as current read block
-			//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: Calling setCurrentBlock(%d) ...', strlen($data)));
+			/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: Calling setCurrentBlock(%d) ...', strlen($data)));
 			$this->setCurrentBlock($data);
 
 			// Then abort here silently
-			//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: EOF reached - EXIT!');
+			/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: EOF reached - EXIT!');
 			return;
 		}
 
@@ -800,7 +853,8 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 		$dataArray = explode(chr(self::SEPARATOR_ENTRIES), $data);
 
 		// This array must contain two elements
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: dataArray=' . print_r($dataArray, true));
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: dataArray()=%d', count($dataArray)));
+		//* PRINTR-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: dataArray=%s', print_r($dataArray, true)));
 		if (count($dataArray) != 2) {
 			// Bad count
 			throw new UnexpectedValueException(sprintf('dataArray()=%d is not expected, want 2', count($dataArray)));
@@ -811,7 +865,7 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 		$this->setBackBuffer($dataArray[1]);
 
 		// Trace message
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: EXIT!');
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: EXIT!');
 	}
 
 	/**
@@ -819,6 +873,7 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 	 * This method will return true if an emptied (nulled) entry has been found.
 	 *
 	 * @return	$isValid	Whether the next entry is valid
+	 * @throws	UnexpectedValueException	If some value is not expected
 	 */
 	public function valid () {
 		// First calculate minimum block length
@@ -826,30 +881,38 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 		$length = $this->getBlockInstance()->calculateMinimumBlockLength();
 
 		// Short be more than zero!
-		assert($length > 0);
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: length=%d', $length));
+		if ($length < 1) {
+			// Throw UVE
+			throw new UnexpectedValueException(sprintf('length=%d is not expected', $length));
+		}
 
 		// Get current seek position
 		$seekPosition = $this->key();
 
 		// Then try to read it
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: seekPosition=%d', $seekPosition));
 		$data = $this->read($length);
 
 		// If some bytes could be read, all is fine
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: data[%s]()=%d', gettype($data), strlen($data)));
 		$isValid = ((is_string($data)) && (strlen($data) > 0));
 
 		// Get header size
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: isValid=%d', intval($isValid)));
 		$headerSize = $this->getHeaderSize();
 
 		// Is the seek position at or beyond the header?
 		if ($seekPosition >= $headerSize) {
 			// Seek back to old position
-			$this->seek($seekPosition);
+			$isValid = ($isValid && $this->seek($seekPosition) === 0);
 		} else {
 			// Seek directly behind the header
-			$this->seek($headerSize);
+			$isValid = ($isValid && $this->seek($headerSize) === 0);
 		}
 
 		// Return result
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: isValid=%d - EXIT!', intval($isValid)));
 		return $isValid;
 	}
 
@@ -860,7 +923,12 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 	 */
 	public function key () {
 		// Call pointer instance
-		return $this->getPointerInstance()->determineSeekPosition();
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: CALLED!');
+		$key = $this->getPointerInstance()->determineSeekPosition();
+
+		// Return key
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-BINARY-FILE: key[%s]=%d - EXIT!', gettype($key), $key));
+		return $key;
 	}
 
 	/**
@@ -870,7 +938,11 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 	 */
 	public function readFileHeader () {
 		// Call block instance
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: CALLED!');
 		$this->getBlockInstance()->readFileHeader();
+
+		// Trace message
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: EXIT!');
 	}
 
 	/**
@@ -880,7 +952,11 @@ abstract class BaseBinaryFile extends BaseAbstractFile {
 	 */
 	public function flushFileHeader () {
 		// Call block instance
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: CALLED!');
 		$this->getBlockInstance()->flushFileHeader();
+
+		// Trace message
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-BINARY-FILE: EXIT!');
 	}
 
 	/**
diff --git a/framework/main/classes/file_directories/class_BaseAbstractFile.php b/framework/main/classes/file_directories/class_BaseAbstractFile.php
index f72d7753..07524bca 100644
--- a/framework/main/classes/file_directories/class_BaseAbstractFile.php
+++ b/framework/main/classes/file_directories/class_BaseAbstractFile.php
@@ -117,6 +117,7 @@ abstract class BaseAbstractFile extends BaseFrameworkSystem implements FilePoint
 	 */
 	public final function getCounter () {
 		// Get it
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-ABSTRACT-FILE: Getting this->totalEntries=%d ... - CALLED!', $this->totalEntries));
 		return $this->totalEntries;
 	}
 
@@ -128,6 +129,7 @@ abstract class BaseAbstractFile extends BaseFrameworkSystem implements FilePoint
 	 */
 	protected final function setCounter (int $counter) {
 		// Set it
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-ABSTRACT-FILE: Setting this->totalEntries=%d ... - CALLED!', $counter));
 		$this->totalEntries = $counter;
 	}
 
@@ -138,7 +140,11 @@ abstract class BaseAbstractFile extends BaseFrameworkSystem implements FilePoint
 	 */
 	protected final function incrementCounter () {
 		// Get it
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-ABSTRACT-FILE: CALLED!');
 		$this->totalEntries++;
+
+		// Trace message
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-ABSTRACT-FILE: EXIT!');
 	}
 
 	/**
diff --git a/framework/main/classes/file_directories/class_BaseFileIo.php b/framework/main/classes/file_directories/class_BaseFileIo.php
index 4a024c8d..71d6d3ba 100644
--- a/framework/main/classes/file_directories/class_BaseFileIo.php
+++ b/framework/main/classes/file_directories/class_BaseFileIo.php
@@ -9,6 +9,7 @@ use Org\Mxchange\CoreFramework\Generic\NullPointerException;
 use Org\Mxchange\CoreFramework\Object\BaseFrameworkSystem;
 
 // Import SPL stuff
+use \InvalidArgumentException;
 use \SplFileObject;
 
 /**
@@ -76,7 +77,7 @@ abstract class BaseFileIo extends BaseFrameworkSystem implements FilePointer, Cl
 	 */
 	public function closeFile () {
 		// Debug message
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d]: fileName=%s - CALLED!', __METHOD__, __LINE__, $this->getFileObject()->getPathname()));
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-IO: fileName=%s - CALLED!', $this->getFileObject()->getPathname()));
 
 		if (is_null($this->getFileObject())) {
 			// Pointer not initialized
@@ -87,13 +88,13 @@ abstract class BaseFileIo extends BaseFrameworkSystem implements FilePointer, Cl
 		}
 
 		// Debug message
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d]: Closing file %s ...', __METHOD__, __LINE__, $this->getFileObject()->getPathname()));
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-IO: Closing file %s ...', $this->getFileObject()->getPathname()));
 
 		// Close the file pointer by NULL-ing it
 		$this->resetFileObject();
 
 		// Debug message
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d]: EXIT!', __METHOD__, __LINE__));
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-IO: EXIT!'));
 	}
 
 	/**
@@ -151,11 +152,18 @@ abstract class BaseFileIo extends BaseFrameworkSystem implements FilePointer, Cl
 	 * @return	$status		Status of file seek: 0 = success, -1 = failed
 	 */
 	public function seek (int $offset, int $whence = SEEK_SET) {
+		// Validate parameter
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-IO: offset=%d,whence=%d - CALLED!', $offset, $whence));
+		if ($offset < 0) {
+			// Throw IAE
+			throw new InvalidArgumentException(sprintf('offset=%d is not valid', $offset));
+		}
+
 		// Seek to position
 		$status = $this->getFileObject()->fseek($offset, $whence);
 
 		// Return status
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] status=%d', __METHOD__, __LINE__, $status));
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-IO: status=%d - EXIT!', $status));
 		return $status;
 	}
 
@@ -167,21 +175,21 @@ abstract class BaseFileIo extends BaseFrameworkSystem implements FilePointer, Cl
 	 */
 	public function size () {
 		// Get current seek position
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-FILE-IO: CALLED!');
 		$seekPosition = $this->determineSeekPosition();
 
 		// Seek to end
 		$seekStatus = $this->seek(0, SEEK_END);
 
 		// Get position again (which is the end of the file)
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] seekStatus=%d', __METHOD__, __LINE__, $seekStatus));
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-IO: seekStatus=%d', $seekStatus));
 		$size = $this->determineSeekPosition();
 
 		// Reset seek position to old
 		$this->seek($seekPosition);
 
 		// Return size
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] size=%s - EXIT!', __METHOD__, __LINE__, $size));
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-IO: size=%s - EXIT!', $size));
 		return $size;
 	}
 
diff --git a/framework/main/classes/file_directories/io/class_FrameworkFileInputOutputPointer.php b/framework/main/classes/file_directories/io/class_FrameworkFileInputOutputPointer.php
index 4e79954f..2805546f 100644
--- a/framework/main/classes/file_directories/io/class_FrameworkFileInputOutputPointer.php
+++ b/framework/main/classes/file_directories/io/class_FrameworkFileInputOutputPointer.php
@@ -149,7 +149,7 @@ class FrameworkFileInputOutputPointer extends BaseFileIo implements InputOutputP
 		}
 
 		// First seek to it, if file size is larger than zero
-		if ($this->getFileSize() > 0 && !$this->seek($seekPosition)) {
+		if (($this->getFileSize() > 0 || $seekPosition > 0) && $this->seek($seekPosition) === -1) {
 			// Could not seek
 			throw new InvalidArgumentException(sprintf('Could not seek to seekPosition=%d', $seekPosition));
 		}
@@ -165,12 +165,15 @@ class FrameworkFileInputOutputPointer extends BaseFileIo implements InputOutputP
 	/**
 	 * Rewinds to the beginning of the file
 	 *
-	 * @return	$status		Status of this operation
+	 * @return	void
 	 */
 	public function rewind () {
 		// Rewind the pointer
 		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('FILE-INPUT-OUTPUT-POINTER: CALLED!');
-		return $this->getFileObject()->rewind();
+		$this->getFileObject()->rewind();
+
+		// Trace message
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('FILE-INPUT-OUTPUT-POINTER: EXIT!');
 	}
 
 	/**
@@ -217,7 +220,7 @@ class FrameworkFileInputOutputPointer extends BaseFileIo implements InputOutputP
 	 */
 	public function read (int $bytes = 0) {
 		// Validatre parameter
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILE-INPUT-OUTPUT-POINTER: bytes=%d - CALLED!', $bytes));
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILE-INPUT-OUTPUT-POINTER: bytes=%d - CALLED!', $bytes));
 		if ($bytes < 0) {
 			// Bytes cannot be lesser than zero
 			throw new InvalidArgumentException(sprintf('bytes=%d is not valid', $bytes));
@@ -233,7 +236,7 @@ class FrameworkFileInputOutputPointer extends BaseFileIo implements InputOutputP
 		}
 
 		// Then return it
-		//* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILE-INPUT-OUTPUT-POINTER: data[%s]=%s - EXIT!', gettype($data), $data));
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILE-INPUT-OUTPUT-POINTER: data[%s]=%s - EXIT!', gettype($data), $data));
 		return $data;
 	}
 
diff --git a/framework/main/classes/index/class_BaseIndex.php b/framework/main/classes/index/class_BaseIndex.php
index 21a79b7d..cd9648b9 100644
--- a/framework/main/classes/index/class_BaseIndex.php
+++ b/framework/main/classes/index/class_BaseIndex.php
@@ -80,6 +80,10 @@ abstract class BaseIndex extends BaseFrameworkSystem {
 				$data,
 				$this->getIteratorInstance()->getHeaderSize()
 			));
+		} elseif (empty(trim($data, chr(0)))) {
+			// Empty file header
+			/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-INDEX: File header is empty - EXIT!');
+			return;
 		} elseif (substr($data, -1, 1) != chr(BaseBinaryFile::SEPARATOR_HEADER_ENTRIES)) {
 			// Bad last character
 			throw new UnexpectedValueException(sprintf('data=%s does not end with "%s"',
@@ -92,6 +96,7 @@ abstract class BaseIndex extends BaseFrameworkSystem {
 		$data = substr($data, 0, -1);
 
 		// And update seek position
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-INDEX: Calling this->iteratorInstance->updateSeekPosition() ...');
 		$this->getIteratorInstance()->updateSeekPosition();
 
 		/*
@@ -149,7 +154,8 @@ abstract class BaseIndex extends BaseFrameworkSystem {
 		);
 
 		// Write it to disk (header is always at seek position 0)
-		$this->getIteratorInstance()->writeData(0, $header, false);
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-INDEX: Calling this->iteratorInstance->writeAtPosition(0, header=%s) ...', $header));
+		$this->getIteratorInstance()->writeAtPosition(0, $header);
 
 		// Trace message
 		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-INDEX: EXIT!');
@@ -174,30 +180,49 @@ abstract class BaseIndex extends BaseFrameworkSystem {
 		$this->setIteratorInstance($iteratorInstance);
 
 		// Calculate header size
-		$this->getIteratorInstance()->setHeaderSize(
+		$headerSize = (
 			strlen(Indexable::INDEX_MAGIC) +
 			strlen(chr(BaseBinaryFile::SEPARATOR_HEADER_DATA)) +
 			BaseBinaryFile::LENGTH_COUNT +
 			strlen(chr(BaseBinaryFile::SEPARATOR_HEADER_ENTRIES))
 		);
 
+		// Set it
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-INDEX: Setting headerSize=%d ...', $headerSize));
+		$this->getIteratorInstance()->setHeaderSize($headerSize);
+
 		// Init counters and gaps array
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-INDEX: Calling this->iteratorInstance->initCountersGapsArray() ...');
 		$this->getIteratorInstance()->initCountersGapsArray();
 
+		// Default is not created
+		$created = false;
+
 		// Is the file's header initialized?
 		if (!$this->getIteratorInstance()->isFileHeaderInitialized()) {
-			// No, then create it (which may pre-allocate the index)
+			// First pre-allocate a bit
+			/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-INDEX: Calling this->iteratorInstance->preAllocateFile(index) ...');
+			$this->getIteratorInstance()->preAllocateFile('index');
+
+			// Then write file header
+			/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-INDEX: Calling this->iteratorInstance->createFileHeader() ...');
 			$this->getIteratorInstance()->createFileHeader();
 
-			// And pre-allocate a bit
-			$this->getIteratorInstance()->preAllocateFile('index');
+			// Mark as freshly created
+			$created = true;
 		}
 
 		// Load the file header
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-INDEX: Calling this->readFileHeader() ...');
 		$this->readFileHeader();
 
-		// Count all entries in file
-		$this->getIteratorInstance()->analyzeFile();
+		// Freshly created?
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-INDEX: created=%d', intval($created)));
+		if (!$created) {
+			// Count all entries in file
+			/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-INDEX: Calling this->iteratorInstance->analyzeFile() ...');
+			$this->getIteratorInstance()->analyzeFile();
+		}
 
 		// Trace message
 		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-INDEX: EXIT!');
diff --git a/framework/main/classes/index/file_stack/class_FileStackIndex.php b/framework/main/classes/index/file_stack/class_FileStackIndex.php
index efb563cc..0d169246 100644
--- a/framework/main/classes/index/file_stack/class_FileStackIndex.php
+++ b/framework/main/classes/index/file_stack/class_FileStackIndex.php
@@ -124,4 +124,32 @@ class FileStackIndex extends BaseIndex implements IndexableStack, Registerable {
 		}
 	}
 
+	/**
+	 * Writes at given position by seeking to it.
+	 *
+	 * @param	$seekPosition	Seek position in file
+	 * @param	$dataStream		Data to be written
+	 * @return	mixed			Number of writes bytes or false on error
+	 * @throws	InvalidArgumentException	If a parameter is not valid
+	 */
+	public function writeAtPosition (int $seekPosition, string $dataStream) {
+		// Validate parameter
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILE-STACK-INDEX: seekPosition=%d,dataStream(%d)=%s - CALLED!', $seekPosition, strlen($dataStream), $dataStream));
+		if ($seekPosition < 0) {
+			// Invalid seek position
+			throw new InvalidArgumentException(sprintf('seekPosition=%d is not valid.', $seekPosition));
+		} elseif (empty($dataStream)) {
+			// Empty dataStream
+			throw new InvalidArgumentException('Parameter "dataStream" is empty');
+		}
+
+		// Call iterated object's method
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILE-STACK-INDEX: Calling this->iteratorInstance->writeAtPosition(%d, %s) ...', $seekPosition, $dataStream));
+		$status = $this->getIteratorInstance()->writeAtPosition($seekPosition, $dataStream);
+
+		// Return status
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILE-STACK-INDEX: status[%s]=%d - EXIT!', gettype($status), $status));
+		return $status;
+	}
+
 }
diff --git a/framework/main/classes/iterator/file/class_FileIterator.php b/framework/main/classes/iterator/file/class_FileIterator.php
index a246927c..24fb2780 100644
--- a/framework/main/classes/iterator/file/class_FileIterator.php
+++ b/framework/main/classes/iterator/file/class_FileIterator.php
@@ -153,11 +153,10 @@ class FileIterator extends BaseIterator implements SeekableWritableFileIterator
 	public function rewind () {
 		// Call block instance
 		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('FILE-ITERATOR: CALLED!');
-		$status = $this->getBlockInstance()->rewind();
+		$this->getBlockInstance()->rewind();
 
-		// Return status
-		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILE-ITERATOR: status=%d - EXIT!', intval($status)));
-		return $status;
+		// Trace message
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('FILE-ITERATOR: EXIT!');
 	}
 
 	/**
@@ -180,19 +179,20 @@ class FileIterator extends BaseIterator implements SeekableWritableFileIterator
 	 * Seeks to given position
 	 *
 	 * @param	$seekPosition	Seek position in file
+	 * @param	$whence			Added to offset (default: only use offset to seek to)
 	 * @return	$status			Status of this operation
 	 * @throws	InvalidArgumentException	If a parameter is not valid
 	 */
-	public function seek (int $seekPosition) {
+	public function seek (int $seekPosition, int $whence = SEEK_SET) {
 		// Validate parameter
-		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILE-ITERATOR: seekPosition=%d - CALLED!', $seekPosition));
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILE-ITERATOR: seekPosition=%d,whence=%d - CALLED!', $seekPosition, $whence));
 		if ($seekPosition < 0) {
 			// Throw IAE
 			throw new InvalidArgumentException(sprintf('seekPosition=%d is not valid', $seekPosition));
 		}
 
 		// Call block instance
-		$status = $this->getBlockInstance()->seek($seekPosition);
+		$status = $this->getBlockInstance()->seek($seekPosition, $whence);
 
 		// Return status
 		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILE-ITERATOR: status=%d - EXIT!', intval($status)));
@@ -445,12 +445,41 @@ class FileIterator extends BaseIterator implements SeekableWritableFileIterator
 		}
 
 		// Call block instance
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILE-ITERATOR: Calling this->blockInstance->writeData(%d,data()=%d,%d) ...', $seekPosition, strlen($data), intval($flushHeader)));
 		$this->getBlockInstance()->writeData($seekPosition, $data, $flushHeader);
 
 		// Trace message
 		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('FILE-ITERATOR: EXIT!');
 	}
 
+	/**
+	 * Writes at given position by seeking to it.
+	 *
+	 * @param	$seekPosition	Seek position in file
+	 * @param	$dataStream		Data to be written
+	 * @return	mixed			Number of writes bytes or false on error
+	 * @throws	InvalidArgumentException	If a parameter is not valid
+	 */
+	public function writeAtPosition (int $seekPosition, string $dataStream) {
+		// Validate parameter
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILE-ITERATOR: seekPosition=%d,dataStream(%d)=%s - CALLED!', $seekPosition, strlen($dataStream), $dataStream));
+		if ($seekPosition < 0) {
+			// Invalid seek position
+			throw new InvalidArgumentException(sprintf('seekPosition=%d is not valid.', $seekPosition));
+		} elseif (empty($dataStream)) {
+			// Empty dataStream
+			throw new InvalidArgumentException('Parameter "dataStream" is empty');
+		}
+
+		// Call iterated object's method
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILE-ITERATOR: Calling this->blockInstance->writeAtPosition(%d, %s) ...', $seekPosition, $dataStream));
+		$status = $this->getBlockInstance()->writeAtPosition($seekPosition, $dataStream);
+
+		// Return status
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILE-ITERATOR: status[%s]=%d - EXIT!', gettype($status), $status));
+		return $status;
+	}
+
 	/**
 	 * Getter for seek position
 	 *
@@ -462,7 +491,7 @@ class FileIterator extends BaseIterator implements SeekableWritableFileIterator
 		$seekPosition = $this->getBlockInstance()->getSeekPosition();
 
 		// Return position
-		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILE-ITERATOR: seekPosition=%d - EXIT!', $seekPosition));
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILE-ITERATOR: seekPosition[%s]=%d - EXIT!', gettype($seekPosition), $seekPosition));
 		return $seekPosition;
 	}
 
@@ -533,7 +562,7 @@ class FileIterator extends BaseIterator implements SeekableWritableFileIterator
 		$seekPosition = $this->getBlockInstance()->searchNextGap($length);
 
 		// Return position
-		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILE-ITERATOR: seekPosition=%d - EXIT!', $seekPosition));
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FILE-ITERATOR: seekPosition[%s]=%d - EXIT!', gettype($seekPosition), $seekPosition));
 		return $seekPosition;
 	}
 
diff --git a/framework/main/classes/output/console/class_ConsoleOutput.php b/framework/main/classes/output/console/class_ConsoleOutput.php
index 3ffff09f..1b11c51a 100644
--- a/framework/main/classes/output/console/class_ConsoleOutput.php
+++ b/framework/main/classes/output/console/class_ConsoleOutput.php
@@ -95,7 +95,7 @@ class ConsoleOutput extends BaseOutput implements OutputStreamer {
 	 * @param	$stripTags	Whether HTML tags shall be stripped out
 	 * @return	void
 	 */
-	public final function output ($outStream = false, $stripTags = false) {
+	public final function output (string $outStream = '', bool $stripTags = false) {
 		print trim($outStream) . PHP_EOL;
 	}
 
diff --git a/framework/main/classes/output/debug/console/class_DebugConsoleOutput.php b/framework/main/classes/output/debug/console/class_DebugConsoleOutput.php
index 7875e001..8f7d19f6 100644
--- a/framework/main/classes/output/debug/console/class_DebugConsoleOutput.php
+++ b/framework/main/classes/output/debug/console/class_DebugConsoleOutput.php
@@ -63,18 +63,18 @@ class DebugConsoleOutput extends BaseDebugOutput implements Debugger, OutputStre
 	 * @param	$stripTags	Whether HTML tags shall be stripped out
 	 * @return	void
 	 */
-	public final function outputStream ($output, $stripTags = false) {
+	public final function outputStream (string $output, bool $stripTags = false) {
 		// Strip HTML tags out?
 		if ($stripTags === true) {
 			// Prepare the output without HTML tags
 			$output = trim(html_entity_decode(strip_tags(stripslashes($output))));
-		} // END - if
+		}
 
 		// Are debug times enabled?
 		if (FrameworkBootstrap::getConfigurationInstance()->getConfigEntry('debug_' . FrameworkBootstrap::getRequestTypeFromSystem() . '_output_timings') == 'Y') {
 			// Output it first
 			$output = $this->getPrintableExecutionTime() . $output;
-		} // END - if
+		}
 
 		// And print it out...
 		printf('%s%s', str_replace('-&gt;', '->', $output), PHP_EOL);
@@ -87,11 +87,11 @@ class DebugConsoleOutput extends BaseDebugOutput implements Debugger, OutputStre
 	 * @param	$stripTags	Whether HTML tags shall be stripped out
 	 * @return	void
 	 */
-	public final function output ($outStream = false, $stripTags = false) {
+	public final function output (string $outStream = '', bool $stripTags = false) {
 		// Empty output will be silently ignored
-		if ($outStream !== false) {
+		if (!empty($outStream)) {
 			$this->outputStream($outStream, $stripTags);
-		} // END - if
+		}
 	}
 
 	/**
diff --git a/framework/main/classes/output/debug/error/class_DebugErrorLogOutput.php b/framework/main/classes/output/debug/error/class_DebugErrorLogOutput.php
index cdbcf57c..7903b910 100644
--- a/framework/main/classes/output/debug/error/class_DebugErrorLogOutput.php
+++ b/framework/main/classes/output/debug/error/class_DebugErrorLogOutput.php
@@ -61,7 +61,7 @@ class DebugErrorLogOutput extends BaseDebugOutput implements Debugger, OutputStr
 	 * @param	$stripTags	Whether HTML tags shall be stripped out
 	 * @return	void
 	 */
-	public final function outputStream ($output, $stripTags = false) {
+	public final function outputStream (string $output, bool $stripTags = false) {
 		// Split multiple lines into and array to put them out line-by-line
 		$errorLines = explode(chr(10), $output);
 
@@ -85,11 +85,11 @@ class DebugErrorLogOutput extends BaseDebugOutput implements Debugger, OutputStr
 	 * @param	$stripTags	Whether HTML tags shall be stripped out
 	 * @return	void
 	 */
-	public final function output ($outStream = false, $stripTags = false) {
+	public final function output (string $outStream = '', bool $stripTags = false) {
 		// Empty output will be silently ignored
-		if ($outStream !== false) {
+		if (!empty($outStream)) {
 			$this->outputStream($outStream);
-		} // END - if
+		}
 	}
 
 	/**
diff --git a/framework/main/classes/output/debug/web/class_DebugWebOutput.php b/framework/main/classes/output/debug/web/class_DebugWebOutput.php
index 2f87522c..e2656b1d 100644
--- a/framework/main/classes/output/debug/web/class_DebugWebOutput.php
+++ b/framework/main/classes/output/debug/web/class_DebugWebOutput.php
@@ -61,7 +61,7 @@ class DebugWebOutput extends BaseDebugOutput implements Debugger, OutputStreamer
 	 * @param	$stripTags	Whether HTML tags shall be stripped out
 	 * @return	void
 	 */
-	public final function outputStream ($output, $stripTags = false) {
+	public final function outputStream (string $output, bool $stripTags = false) {
 		// Strip out any <br />
 		$output = str_replace('<br />', '', $output);
 		printf('<!-- %s -->' . PHP_EOL, stripslashes($output));
@@ -74,11 +74,11 @@ class DebugWebOutput extends BaseDebugOutput implements Debugger, OutputStreamer
 	 * @param	$stripTags	Whether HTML tags shall be stripped out
 	 * @return	void
 	 */
-	public final function output ($outStream = false, $stripTags = false) {
+	public final function output (string $outStream = '', bool $stripTags = false) {
 		// Empty output will be silently ignored
-		if ($outStream !== false) {
+		if (!empty($outStream)) {
 			$this->outputStream($outStream, $stripTags);
-		} // END - if
+		}
 	}
 
 	/**
diff --git a/framework/main/classes/output/web/class_WebOutput.php b/framework/main/classes/output/web/class_WebOutput.php
index 44e24e01..6abfc10f 100644
--- a/framework/main/classes/output/web/class_WebOutput.php
+++ b/framework/main/classes/output/web/class_WebOutput.php
@@ -82,7 +82,7 @@ class WebOutput extends BaseOutput implements OutputStreamer, Registerable {
 	 * @param	$stripTags	Whether HTML tags shall be stripped out
 	 * @return	void
 	 */
-	public final function output ($outStream = false, $stripTags = false) {
+	public final function output (string $outStream = '', bool $stripTags = false) {
 		print(stripslashes($outStream));
 	}
 
diff --git a/framework/main/classes/stacker/file/class_BaseFileStack.php b/framework/main/classes/stacker/file/class_BaseFileStack.php
index 54205230..859eebd8 100644
--- a/framework/main/classes/stacker/file/class_BaseFileStack.php
+++ b/framework/main/classes/stacker/file/class_BaseFileStack.php
@@ -81,9 +81,9 @@ abstract class BaseFileStack extends BaseStacker implements StackableFile {
 
 		// Then read it (see constructor for calculation)
 		$data = $this->getIteratorInstance()->read($this->getIteratorInstance()->getHeaderSize());
-		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: Read %d bytes (%d wanted).', strlen($data), $this->getIteratorInstance()->getHeaderSize()));
 
 		// Have all requested bytes been read?
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: Read %d bytes (%d wanted).', strlen($data), $this->getIteratorInstance()->getHeaderSize()));
 		if (strlen($data) != $this->getIteratorInstance()->getHeaderSize()) {
 			// Bad data length
 			throw new UnexpectedValueException(sprintf('data(%d)=%s does not match iteratorInstance->headerSize=%d',
@@ -91,6 +91,10 @@ abstract class BaseFileStack extends BaseStacker implements StackableFile {
 				$data,
 				$this->getIteratorInstance()->getHeaderSize()
 			));
+		} elseif (empty(trim($data, chr(0)))) {
+			// Empty header, file is freshly pre-allocated
+			/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-FILE-STACK: Empty file header detected - EXIT!');
+			return;
 		}
 
 		// Last character must be the separator
@@ -107,6 +111,7 @@ abstract class BaseFileStack extends BaseStacker implements StackableFile {
 		$data = substr($data, 0, -1);
 
 		// And update seek position
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-FILE-STACK: Calling this->iteratorInstance->updateSeekPosition() ...');
 		$this->getIteratorInstance()->updateSeekPosition();
 
 		/*
@@ -156,7 +161,7 @@ abstract class BaseFileStack extends BaseStacker implements StackableFile {
 		$this->getIteratorInstance()->setHeader($header);
 
 		// Trace message
-		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: EXIT!', __METHOD__, __LINE__));
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-FILE-STACK: EXIT!');
 	}
 
 	/**
@@ -174,13 +179,13 @@ abstract class BaseFileStack extends BaseStacker implements StackableFile {
 			// Separator magic<->count
 			chr(BaseBinaryFile::SEPARATOR_HEADER_DATA),
 
-			// Total entries (will be zero) and pad it to 20 chars
+			// Padded total entries
 			str_pad(StringUtils::dec2hex($this->getIteratorInstance()->getCounter()), BaseBinaryFile::LENGTH_COUNT, '0', STR_PAD_LEFT),
 
 			// Separator count<->seek position
 			chr(BaseBinaryFile::SEPARATOR_HEADER_DATA),
 
-			// Position (will be zero)
+			// Padded seek position
 			str_pad(StringUtils::dec2hex($this->getIteratorInstance()->getSeekPosition(), 2), BaseBinaryFile::LENGTH_POSITION, '0', STR_PAD_LEFT),
 
 			// Separator position<->entries
@@ -188,7 +193,8 @@ abstract class BaseFileStack extends BaseStacker implements StackableFile {
 		);
 
 		// Write it to disk (header is always at seek position 0)
-		$this->getIteratorInstance()->writeData(0, $header, false);
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: Calling this->iteratorInstance->writeAtPosition(0, header=%s) ...', $header));
+		$this->getIteratorInstance()->writeAtPosition(0, $header);
 
 		// Trace message
 		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-FILE-STACK: EXIT!');
@@ -221,7 +227,7 @@ abstract class BaseFileStack extends BaseStacker implements StackableFile {
 		$this->setIteratorInstance($iteratorInstance);
 
 		// Calculate header size
-		$this->getIteratorInstance()->setHeaderSize(
+		$headerSize = (
 			strlen(StackableFile::STACK_MAGIC) +
 			strlen(chr(BaseBinaryFile::SEPARATOR_HEADER_DATA)) +
 			BaseBinaryFile::LENGTH_COUNT +
@@ -230,28 +236,48 @@ abstract class BaseFileStack extends BaseStacker implements StackableFile {
 			strlen(chr(BaseBinaryFile::SEPARATOR_HEADER_ENTRIES))
 		);
 
+		// Setting it
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: Setting headerSize=%d ...', $headerSize));
+		$this->getIteratorInstance()->setHeaderSize($headerSize);
+
 		// Init counters and gaps array
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-FILE-STACK: Calling this->iteratorInstance->initCountersGapsArray() ...');
 		$this->getIteratorInstance()->initCountersGapsArray();
 
+		// Default is not created/already exists
+		$created = false;
+
 		// Is the file's header initialized?
 		if (!$this->getIteratorInstance()->isFileHeaderInitialized()) {
-			// No, then create it (which may pre-allocate the stack)
+			// First pre-allocate a bit
+			/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-FILE-STACK: Calling this->iteratorInstance->preAllocateFile(file_stack) ...');
+			$this->getIteratorInstance()->preAllocateFile('file_stack');
+
+			// Then create file header
+			/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-FILE-STACK: this->iteratorInstance->createFileHeader() ...');
 			$this->getIteratorInstance()->createFileHeader();
 
-			// And pre-allocate a bit
-			$this->getIteratorInstance()->preAllocateFile('file_stack');
+			// Set flag
+			$created = true;
 		}
 
 		// Load the file header
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-FILE-STACK: Calling this->readFileHeader() ...');
 		$this->readFileHeader();
 
-		// Count all entries in file
-		$this->getIteratorInstance()->analyzeFile();
+		// Not created/already exists?
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: created=%d', intval($created)));
+		if (!$created) {
+			// Count all entries in file
+			/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('BASE-FILE-STACK: Calling this->iteratorInstance->analyzeFile() ...');
+			$this->getIteratorInstance()->analyzeFile();
+		}
 
 		/*
 		 * Get stack index instance. This can be used for faster
 		 * "defragmentation" and startup.
 		 */
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: fileInfoInstance[%s]=%s,type=%s', get_class($fileInfoInstance), $fileInfoInstance, $type));
 		$indexInstance = FileStackIndexFactory::createFileStackIndexInstance($fileInfoInstance, $type);
 
 		// And set it here
@@ -618,10 +644,25 @@ abstract class BaseFileStack extends BaseStacker implements StackableFile {
 	 * @throws	UnsupportedOperationException	This method is not (and maybe never will be) supported
 	 */
 	public function writeData (int $seekPosition, string $data, bool $flushHeader = true) {
+		// Not supported
 		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: seekPosition=%s,data[]=%s,flushHeader=%d', $seekPosition, gettype($data), intval($flushHeader)));
 		throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
 	}
 
+	/**
+	 * Writes at given position by seeking to it.
+	 *
+	 * @param	$seekPosition	Seek position in file
+	 * @param	$dataStream		Data to be written
+	 * @return	mixed			Number of writes bytes or false on error
+	 * @throws	UnsupportedOperationException	This method is not (and maybe never will be) supported
+	 */
+	public function writeAtPosition (int $seekPosition, string $dataStream) {
+		// Not supported
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('BASE-FILE-STACK: seekPosition=%d,dataStream(%d)=%s - CALLED!', $seekPosition, strlen($dataStream), $dataStream));
+		throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
+	}
+
 	/**
 	 * Writes given value to the file and returns a hash and gap position for it
 	 *
diff --git a/framework/main/classes/stacker/file/fifo/class_FiFoFileStack.php b/framework/main/classes/stacker/file/fifo/class_FiFoFileStack.php
index f2fce745..42eab523 100644
--- a/framework/main/classes/stacker/file/fifo/class_FiFoFileStack.php
+++ b/framework/main/classes/stacker/file/fifo/class_FiFoFileStack.php
@@ -160,12 +160,13 @@ class FiFoFileStack extends BaseFileStack implements StackableFile, Calculatable
 	 * Seeks to given position
 	 *
 	 * @param	$seekPosition	Seek position in file
+	 * @param	$whence			Added to offset (default: only use offset to seek to)
 	 * @return	$status			Status of this operation
 	 * @throws	InvalidArgumentException	If a parameter is invalid
 	 */
-	public function seek (int $seekPosition) {
+	public function seek (int $seekPosition, int $whence = SEEK_SET) {
 		// Validate parameter
-		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FIFO-FILE-STACK: seekPosition=%d - CALLED!', $seekPosition));
+		/* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FIFO-FILE-STACK: seekPosition=%d,whence=%d - CALLED!', $seekPosition, $whence));
 		if ($seekPosition < 0) {
 			// Invalid seek position
 			throw new InvalidArgumentException(sprintf('seekPosition=%d is not valid', $seekPosition));
diff --git a/framework/main/interfaces/block/class_Block.php b/framework/main/interfaces/block/class_Block.php
index 9f593ecc..5c25324b 100644
--- a/framework/main/interfaces/block/class_Block.php
+++ b/framework/main/interfaces/block/class_Block.php
@@ -139,6 +139,16 @@ interface Block extends FrameworkInterface {
 	 */
 	function writeData (int $seekPosition, string $data, bool $flushHeader = true);
 
+	/**
+	 * Writes at given position by seeking to it.
+	 *
+	 * @param	$seekPosition	Seek position in file
+	 * @param	$dataStream		Data to be written
+	 * @return	mixed			Number of writes bytes or false on error
+	 * @throws	InvalidArgumentException	If a parameter is not valid
+	 */
+	function writeAtPosition (int $seekPosition, string $dataStream);
+
 	/**
 	 * Searches for next suitable gap the given length of data can fit in
 	 * including padding bytes.
diff --git a/framework/main/interfaces/debug/class_Debugger.php b/framework/main/interfaces/debug/class_Debugger.php
index 437a462c..7f2ac43f 100644
--- a/framework/main/interfaces/debug/class_Debugger.php
+++ b/framework/main/interfaces/debug/class_Debugger.php
@@ -35,6 +35,6 @@ interface Debugger extends FrameworkInterface {
 	 * @param	$stripTags	Whether HTML tags shall be stripped out
 	 * @return	void
 	 */
-	function outputStream ($output, $stripTags = false);
+	function outputStream (string $output, bool $stripTags = false);
 
 }
diff --git a/framework/main/interfaces/io/output/class_OutputStreamer.php b/framework/main/interfaces/io/output/class_OutputStreamer.php
index b7b7ae72..1448c698 100644
--- a/framework/main/interfaces/io/output/class_OutputStreamer.php
+++ b/framework/main/interfaces/io/output/class_OutputStreamer.php
@@ -35,6 +35,6 @@ interface OutputStreamer extends StreamableOutput {
 	 * @param	$stripTags	Whether HTML tags shall be stripped out
 	 * @return	void
 	 */
-	function output ($outStream = false, $stripTags = false);
+	function output (string $outStream = '', bool $stripTags = false);
 
 }
diff --git a/framework/main/interfaces/iterator/file/class_SeekableWritableFileIterator.php b/framework/main/interfaces/iterator/file/class_SeekableWritableFileIterator.php
index 4a497bf3..728a3457 100644
--- a/framework/main/interfaces/iterator/file/class_SeekableWritableFileIterator.php
+++ b/framework/main/interfaces/iterator/file/class_SeekableWritableFileIterator.php
@@ -154,6 +154,15 @@ interface SeekableWritableFileIterator extends SeekableIterator {
 	 */
 	function writeData (int $seekPosition, string $data, bool $flushHeader = true);
 
+	/**
+	 * Writes at given position by seeking to it.
+	 *
+	 * @param	$seekPosition	Seek position in file
+	 * @param	$data			Data to be written
+	 * @return	mixed			Number of writes bytes or false on error
+	 */
+	function writeAtPosition (int $seedPosition, string $data);
+
 	/**
 	 * Getter for seek position
 	 *