]> git.mxchange.org Git - core.git/blobdiff - inc/classes/main/file_directories/class_BaseFile.php
Added isFileOnlyGaps() and getFileSize(), both are "basicly finished".
[core.git] / inc / classes / main / file_directories / class_BaseFile.php
index 632cbdcec73bce2dfe7dffaf79711c2de2178988..d7a73372baea2ccc1e949bf7687516f63cc9bfa4 100644 (file)
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 class BaseFile extends BaseFrameworkSystem {
+       /**
+        * Separator for header data
+        */
+       const SEPARATOR_HEADER_DATA = 0x01;
+
+       /**
+        * Separator header->entries
+        */
+       const SEPARATOR_HEADER_ENTRIES = 0x02;
+
+       /**
+        * Separator hash->name
+        */
+       const SEPARATOR_HASH_NAME = 0x03;
+
+       /**
+        * Separator entry->entry
+        */
+       const SEPARATOR_ENTRIES = 0x04;
+
+       /**
+        * Separator type->position
+        */
+       const SEPARATOR_TYPE_POSITION = 0x05;
+
+       /**
+        * Length of count
+        */
+       const LENGTH_COUNT = 20;
+
+       /**
+        * Length of position
+        */
+       const LENGTH_POSITION = 20;
+
+       /**
+        * Length of name
+        */
+       const LENGTH_NAME = 10;
+
+       /**
+        * Maximum length of entry type
+        */
+       const LENGTH_TYPE = 20;
+
+       //***** Array elements for 'gaps' array *****
+
+       /**
+        * Start of gap
+        */
+       const GAPS_INDEX_START = 'start';
+
+       /**
+        * End of gap
+        */
+       const GAPS_INDEX_END = 'end';
+
+       /**
+        * Counter for total entries
+        */
+       private $totalEntries = 0;
+
+       /**
+        * Current seek position
+        */
+       private $seekPosition = 0;
+
+       /**
+        * Size of header
+        */
+       private $headerSize = 0;
+
+       /**
+        * File header
+        */
+       private $header = array();
+
+       /**
+        * Seek positions for gaps ("fragmentation")
+        */
+       private $gaps = array();
+
+       /**
+        * Seek positions for damaged entries (e.g. mismatching hash sum, ...)
+        */
+       private $damagedEntries = array();
+
        /**
         * The current file we are working in
         */
@@ -64,6 +151,230 @@ y   * @return      void
                parent::__destruct();
        }
 
+       /**
+        * Checks whether the abstracted file only contains gaps by counting all
+        * gaps' bytes together and compare it to total length.
+        *
+        * @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__)->debugOutput(sprintf('[%s:%d:] this->gaps[0]=%s,this->gaps[%s]=%s', __METHOD__, __LINE__, print_r($this->gaps[0], TRUE), (count($this->gaps) - 1), print_r($this->gaps[count($this->gaps) - 1], TRUE)));
+               } // END - if
+               */
+
+               // Now count every gap
+               $gapsSize = 0;
+               foreach ($this->gaps as $gap) {
+                       // Calculate size of found gap: end-start including both
+                       $gapsSize += ($gap[self::GAPS_INDEX_END] - $gap[self::GAPS_INDEX_START]);
+               } // END - if
+
+               // Debug output
+               //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] gapsSize=%s,this->headerSize=%s', __METHOD__, __LINE__, $gapsSize, $this->getHeaderSize()));
+
+               // Total gap size + header size must be same as file size
+               $isGapsOnly = (($this->getHeaderSize() + $gapsSize) == $this->getFileSize());
+
+               // Return status
+               return $isGapsOnly;
+       }
+
+       /**
+        * Initializes counter for valid entries, arrays for damaged entries and
+        * an array for gap seek positions. If you call this method on your own,
+        * please re-analyze the file structure. So you are better to call
+        * analyzeFile() instead of this method.
+        *
+        * @return      void
+        */
+       public function initCountersGapsArray () {
+               // Init counter and seek position
+               $this->setCounter(0);
+               $this->setSeekPosition(0);
+
+               // Init arrays
+               $this->gaps = array();
+               $this->damagedEntries = array();
+       }
+
+       /**
+        * "Getter" for abstracted file size
+        *
+        * @return      $fileSize       Size of abstracted file
+        */
+       public function getFileSize () {
+               // Call block instanze
+               return $this->getBlockInstance()->getFileSize();
+       }
+
+       /**
+        * Getter for total entries
+        *
+        * @return      $totalEntries   Total entries in this file
+        */
+       public final function getCounter () {
+               // Get it
+               return $this->totalEntries;
+       }
+
+       /**
+        * Setter for total entries
+        *
+        * @param       $totalEntries   Total entries in this file
+        * @return      void
+        */
+       protected final function setCounter ($counter) {
+               // Set it
+               $this->totalEntries = $counter;
+       }
+
+       /**
+        * Increment counter
+        *
+        * @return      void
+        */
+       protected final function incrementCounter () {
+               // Get it
+               $this->totalEntries++;
+       }
+
+       /**
+        * Getter for header size
+        *
+        * @return      $totalEntries   Size of file header
+        */
+       public final function getHeaderSize () {
+               // Get it
+               return $this->headerSize;
+       }
+
+       /**
+        * Setter for header size
+        *
+        * @param       $headerSize             Size of file header
+        * @return      void
+        */
+       public final function setHeaderSize ($headerSize) {
+               // Set it
+               $this->headerSize = $headerSize;
+       }
+
+       /**
+        * Getter for header array
+        *
+        * @return      $totalEntries   Size of file header
+        */
+       public final function getHeader () {
+               // Get it
+               return $this->header;
+       }
+
+       /**
+        * Setter for header
+        *
+        * @param       $header         Array for a file header
+        * @return      void
+        */
+       public final function setHeader (array $header) {
+               // Set it
+               $this->header = $header;
+       }
+
+       /**
+        * Getter for seek position
+        *
+        * @return      $seekPosition   Current seek position (stored here in object)
+        */
+       protected final function getSeekPosition () {
+               // Get it
+               return $this->seekPosition;
+       }
+
+       /**
+        * Setter for seek position
+        *
+        * @param       $seekPosition   Current seek position (stored here in object)
+        * @return      void
+        */
+       protected final function setSeekPosition ($seekPosition) {
+               // And set it
+               $this->seekPosition = $seekPosition;
+       }
+
+       /**
+        * Updates seekPosition attribute from file to avoid to much access on file.
+        *
+        * @return      void
+        */
+       public function updateSeekPosition () {
+               //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
+
+               // Get key (= seek position)
+               $seekPosition = $this->key();
+               //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Setting seekPosition=%s', __METHOD__, __LINE__, $seekPosition));
+
+               // And set it here
+               $this->setSeekPosition($seekPosition);
+
+               //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
+       }
+
+       /**
+        * Seeks to beginning of file, updates seek position in this object and
+        * flushes the header.
+        *
+        * @return      void
+        */
+       protected function rewindUpdateSeekPosition () {
+               //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
+
+               // flushFileHeader must be callable
+               assert(is_callable(array($this, 'flushFileHeader')));
+
+               // Seek to beginning of file
+               $this->rewind();
+
+               // And update seek position ...
+               $this->updateSeekPosition();
+
+               // ... to write it back into the file
+               $this->flushFileHeader();
+
+               //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!!', __METHOD__, __LINE__));
+       }
+
+       /**
+        * Seeks to old position
+        *
+        * @return      void
+        */
+       protected function seekToOldPosition () {
+               //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
+
+               // Seek to currently ("old") saved position
+               $this->seek($this->getSeekPosition());
+
+               //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!!', __METHOD__, __LINE__));
+       }
+
+       /**
+        * Checks whether the block separator has been found
+        *
+        * @param       $str            String to look in
+        * @return      $isFound        Whether the block separator has been found
+        */
+       public static function isBlockSeparatorFound ($str) {
+               // Determine it
+               $isFound = (strpos($str, chr(self::SEPARATOR_ENTRIES)) !== FALSE);
+
+               // Return result
+               return $isFound;
+       }
+
        /**
         * Getter for the file pointer
         *
@@ -141,6 +452,16 @@ y   * @return      void
                $this->currentBlock = $currentBlock;
        }
 
+       /**
+        * Gets currently read data
+        *
+        * @return      $current        Currently read data
+        */
+       public function getCurrentBlock () {
+               // Return it
+               return $this->currentBlock;
+       }
+
        /**
         * Initializes this file class
         *
@@ -155,6 +476,171 @@ y  * @return      void
                $this->setPointerInstance($pointerInstance);
        }
 
+       /**
+        * Writes data at given position
+        *
+        * @param       $seekPosition   Seek position
+        * @param       $data                   Data to be written
+        * @param       $flushHeader    Whether to flush the header (default: flush)
+        * @return      void
+        */
+       protected function writeData ($seekPosition, $data, $flushHeader = TRUE) {
+               //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] seekPosition=%s,data()=%s - CALLED!', __METHOD__, __LINE__, $seekPosition, strlen($data)));
+
+               // Write data at given position
+               $this->getPointerInstance()->writeAtPosition($seekPosition, $data);
+
+               // Update seek position
+               $this->updateSeekPosition();
+
+               // Flush the header?
+               if ($flushHeader === TRUE) {
+                       // Flush header
+                       $this->flushFileHeader();
+
+                       // Seek to old position
+                       $this->seekToOldPosition();
+               } // END - if
+
+               //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
+       }
+
+       /**
+        * Marks the currently loaded block as empty (with length of the block)
+        *
+        * @param       $length         Length of the block
+        * @return      void
+        */
+       protected function markCurrentBlockAsEmpty ($length) {
+               // Get current seek position
+               $currentPosition = $this->key();
+
+               // Now add it as gap entry
+               array_push($this->gaps, array(
+                       self::GAPS_INDEX_START  => ($currentPosition - $length),
+                       self::GAPS_INDEX_END    => $currentPosition,
+               ));
+       }
+
+       /**
+        * Checks whether the file header is initialized
+        *
+        * @return      $isInitialized  Whether the file header is initialized
+        */
+       public function isFileHeaderInitialized () {
+               //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
+
+               // Default is not initialized
+               $isInitialized = FALSE;
+
+               // Is the file initialized?
+               if ($this->isFileInitialized()) {
+                       // Some bytes has been written, so rewind to start of it.
+                       $rewindStatus = $this->rewind();
+                       //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] rewindStatus=%s', __METHOD__, __LINE__, $rewindStatus));
+
+                       // Is the rewind() call successfull?
+                       if ($rewindStatus != 1) {
+                               // Something bad happened
+                               self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Could not rewind().', __METHOD__, __LINE__));
+                       } // END - if
+
+                       // Read file header
+                       $this->readFileHeader();
+
+                       // The above method does already check the header
+                       $isInitialized = TRUE;
+               } // END - if
+
+               // Return result
+               //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] isInitialized=%d - EXIT!', __METHOD__, __LINE__, intval($isInitialized)));
+               return $isInitialized;
+       }
+
+       /**
+        * Checks whether the assigned file has been initialized
+        *
+        * @return      $isInitialized          Whether the file's size is zero
+        */
+       public function isFileInitialized () {
+               //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
+
+               // Get it from iterator which holds the pointer instance. If FALSE is returned
+               $fileSize = $this->size();
+               //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] fileSize=%s', __METHOD__, __LINE__, $fileSize));
+
+               /*
+                * The returned file size should not be FALSE or NULL as this means
+                * that the pointer class does not work correctly.
+                */
+               assert(is_int($fileSize));
+
+               // Is more than 0 returned?
+               $isInitialized = ($fileSize > 0);
+
+               // Return result
+               //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] isInitialized=%d - EXIT!', __METHOD__, __LINE__, intval($isInitialized)));
+               return $isInitialized;
+       }
+
+       /**
+        * Creates the assigned file
+        *
+        * @return      void
+        */
+       public function createFileHeader () {
+               //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
+
+               // The file's header should not be initialized here
+               assert(!$this->isFileHeaderInitialized());
+
+               // Simple flush file header which will create it.
+               $this->flushFileHeader();
+
+               // Rewind seek position (to beginning of file) and update/flush file header
+               $this->rewindUpdateSeekPosition();
+
+               //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!!', __METHOD__, __LINE__));
+       }
+
+       /**
+        * Pre-allocates file (if enabled) with some space for later faster write access.
+        *
+        * @param       $type   Type of the file
+        * @return      void
+        */
+       public function preAllocateFile ($type) {
+               //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
+
+               // Is it enabled?
+               if ($this->getConfigInstance()->getConfigEntry($type . '_pre_allocate_enabled') != 'Y') {
+                       // Not enabled
+                       self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Not pre-allocating file.', __METHOD__, __LINE__));
+
+                       // Don't continue here.
+                       return;
+               } // END - if
+
+               // Message to user
+               self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Pre-allocating file ...', __METHOD__, __LINE__));
+
+               // Calculate minimum length for one entry
+               $minLengthEntry = $this->getBlockInstance()->calculateMinimumBlockLength();
+               //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] minLengthEntry=%s', __METHOD__, __LINE__, $minLengthEntry));
+
+               // Calulcate seek position
+               $seekPosition = $minLengthEntry * $this->getConfigInstance()->getConfigEntry($type . '_pre_allocate_count');
+               //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] seekPosition=%s', __METHOD__, __LINE__, $seekPosition));
+
+               // Now simply write a NUL there. This will pre-allocate the file.
+               $this->writeData($seekPosition, chr(0));
+
+               // Rewind seek position (to beginning of file) and update/flush file header
+               $this->rewindUpdateSeekPosition();
+
+               //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
+       }
+
        /**
         * Close a file source and set it's instance to null and the file name
         * to empty
@@ -175,6 +661,7 @@ y    * @return      void
         * @return      $seekPosition   Current seek position
         */
        public function determineSeekPosition () {
+               // Call pointer instance
                return $this->getPointerInstance()->determineSeekPosition();
        }
 
@@ -186,6 +673,7 @@ y    * @return      void
         * @return      $status         Status of file seek: 0 = success, -1 = failed
         */
        public function seek ($offset, $whence = SEEK_SET) {
+               // Call pointer instance
                return $this->getPointerInstance()->seek($offset, $whence);
        }
 
@@ -196,6 +684,7 @@ y    * @return      void
         * @todo        Handle seekStatus
         */
        public function size () {
+               // Call pointer instance
                return $this->getPointerInstance()->size();
        }
 
@@ -208,6 +697,7 @@ y    * @return      void
         * @throws      InvalidResourceException        If there is being set
         */
        public function readFromFile () {
+               // Call pointer instance
                return $this->getPointerInstance()->readFromFile();
        }
 
@@ -218,6 +708,7 @@ y    * @return      void
         * @return      $data   Data read from file
         */
        public function read ($bytes) {
+               // Call pointer instance
                return $this->getPointerInstance()->read($bytes);
        }
 
@@ -232,6 +723,7 @@ y    * @return      void
         *                                                                                      an invalid file resource
         */
        public function writeToFile ($dataStream) {
+               // Call pointer instance
                return $this->getPointerInstance()->writeToFile($dataStream);
        }
 
@@ -241,6 +733,7 @@ y    * @return      void
         * @return      $status         Status of this operation
         */
        public function rewind () {
+               // Call pointer instance
                return $this->getPointerInstance()->rewind();
        }
 
@@ -250,7 +743,8 @@ y    * @return      void
         * @return      $isEndOfFileReached             Whether the EOF has been reached
         */
        public final function isEndOfFileReached () {
-               return $this->isEndOfFileReached();
+               // Call pointer instance
+               return $this->getPointerInstance()->isEndOfFileReached();
        }
 
        /**
@@ -281,12 +775,43 @@ y  * @return      void
                        $this->next();
 
                        // Get current entry
-                       $current = $this->current();
-
-                       // Simply output it
-                       self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] current=%s', __METHOD__, __LINE__, print_r($current, TRUE)));
+                       $current = $this->getCurrentBlock();
+
+                       /*
+                        * If the block is empty, maybe the whole file is? This could mean
+                        * that the file has been pre-allocated.
+                        */
+                       if (empty($current)) {
+                               // Then skip this part
+                               continue;
+                       } // END - if
+
+                       // Debug message
+                       /* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] current()=%s', __METHOD__, __LINE__, strlen($current)));
                } // END - while
 
+               // If the last read block is empty, check gaps
+               if (empty($current)) {
+                       // Output message
+                       self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Found a total of %s gaps.', __METHOD__, __LINE__, count($this->gaps)));
+
+                       // Check gaps, if the whole file is empty.
+                       if ($this->isFileOnlyGaps()) {
+                               // Only gaps, so don't continue here.
+                               return;
+                       } // END - if
+
+                       /*
+                        * The above call has calculated a total size of all gaps. If the
+                        * percentage of gaps passes a "soft" limit and last
+                        * defragmentation is to far in the past, or if a "hard" limit has
+                        * reached, run defragmentation.
+                        */
+                       if ($this->isDefragmentationNeeded()) {
+                               // Run "defragmentation"
+                               $this->doRunDefragmentation();
+                       } // END - if
+               } // END - if
                //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
        }
 
@@ -294,7 +819,6 @@ y    * @return      void
         * Advances to next "block" of bytes
         *
         * @return      void
-        * @todo        This method will load large but empty files in a whole
         */
        public function next () {
                // Is there nothing to read?
@@ -303,26 +827,53 @@ y  * @return      void
                        return;
                } // END - if
 
+               // Debug message
+               //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d] key()=%s', __FUNCTION__, __LINE__, $this->key()));
+
                // Make sure the block instance is set
                assert($this->getBlockInstance() instanceof CalculatableBlock);
 
                // First calculate minimum block length
-               $length = $this->getBlockInstance()->caluclateMinimumBlockLength();
+               $length = $this->getBlockInstance()->calculateMinimumBlockLength();
+               //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d] length=%s', __FUNCTION__, __LINE__, $length));
 
                // Short be more than zero!
                assert($length > 0);
 
-               // Wait until a entry/block separator has been found
+               // Read possibly back-buffered bytes from previous call of next().
                $data = $this->getBackBuffer();
-               while ((!$this->isEndOfFileReached()) && (!$this->getBlockInstance()->isBlockSeparatorFound($data))) {
-                       // Then read the block
-                       $data .= $this->read($length);
-                       //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('data()=' . strlen($data));
-               } // END - if
+
+               /*
+                * Read until a entry/block separator has been found. The next read
+                * "block" may not fit, so this loop will continue until the EOB or EOF
+                * has been reached whatever comes first.
+                */
+               while ((!$this->isEndOfFileReached()) && (!self::isBlockSeparatorFound($data))) {
+                       // Then read the next possible block
+                       $block = $this->read($length);
+
+                       // Debug message
+                       //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d] block()=%s,length=%s', __FUNCTION__, __LINE__, strlen($block), $length));
+
+                       // Is it all empty?
+                       if (strlen(trim($block)) == 0) {
+                               // Mark this block as empty
+                               $this->markCurrentBlockAsEmpty(strlen($block));
+
+                               // Skip to next block
+                               continue;
+                       } // END - if
+
+                       // At this block then
+                       $data .= $block;
+
+                       // A debug message
+                       //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d] data()=%s', __FUNCTION__, __LINE__, strlen($data)));
+               } // END - while
 
                // EOF reached?
                if ($this->isEndOfFileReached()) {
-                       // Set whole data as current block
+                       // Set whole data as current read block
                        //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('Calling setCurrentBlock(' . strlen($data) . ') ...');
                        $this->setCurrentBlock($data);
 
@@ -338,7 +889,7 @@ y    * @return      void
                $this->initBackBuffer();
 
                // Separate data
-               $dataArray = explode(self::getBlockSeparator(), $data);
+               $dataArray = explode(chr(self::SEPARATOR_ENTRIES), $data);
 
                // This array must contain two elements
                //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('dataArray=' . print_r($dataArray, TRUE));
@@ -357,10 +908,10 @@ y  * @return      void
         */
        public function valid () {
                // Make sure the block instance is set
-               assert($this->getBlockInstance() instanceof CalculatableBlock);
+               assert($this->getBlockInstance() instanceof Block);
 
                // First calculate minimum block length
-               $length = $this->getBlockInstance()->caluclateMinimumBlockLength();
+               $length = $this->getBlockInstance()->calculateMinimumBlockLength();
 
                // Short be more than zero!
                assert($length > 0);
@@ -375,7 +926,7 @@ y    * @return      void
                $isValid = ((is_string($data)) && (strlen($data) > 0));
 
                // Get header size
-               $headerSize = $this->getBlockInstance()->getHeaderSize();
+               $headerSize = $this->getHeaderSize();
 
                // Is the seek position at or beyond the header?
                if ($seekPosition >= $headerSize) {
@@ -389,6 +940,42 @@ y   * @return      void
                // Return result
                return $isValid;
        }
+
+       /**
+        * Gets current seek position ("key").
+        *
+        * @return      $key    Current key in iteration
+        */
+       public function key () {
+               // Call pointer instance
+               return $this->getPointerInstance()->determineSeekPosition();
+       }
+
+       /**
+        * Reads the file header
+        *
+        * @return      void
+        */
+       public function readFileHeader () {
+               // Make sure the block instance is set
+               assert($this->getBlockInstance() instanceof Block);
+
+               // Call block instance
+               $this->getBlockInstance()->readFileHeader();
+       }
+
+       /**
+        * Flushes the file header
+        *
+        * @return      void
+        */
+       public function flushFileHeader () {
+               // Make sure the block instance is set
+               assert($this->getBlockInstance() instanceof Block);
+
+               // Call block instance
+               $this->getBlockInstance()->flushFileHeader();
+       }
 }
 
 // [EOF]