+ return fwrite($this->getPointer(), $dataStream, strlen($dataStream));
+ }
+
+ /**
+ * Writes at given position by seeking to it.
+ *
+ * @param $seekPosition Seek position in file
+ * @param $data Data to be written
+ * @return mixed Number of writes bytes or FALSE on error
+ */
+ public function writeAtPosition ($seekPosition, $data) {
+ // First seek to it
+ $this->seek($seekPosition);
+
+ // Then write the data at that position
+ return $this->writeToFile($data);
+ }
+
+ /**
+ * Rewinds to the beginning of the file
+ *
+ * @return $status Status of this operation
+ */
+ public function rewind () {
+ // Validate the pointer
+ $this->validateFilePointer();
+
+ // Rewind the pointer
+ return rewind($this->getPointer());
+ }
+
+ /**
+ * Seeks to given position
+ *
+ * @param $seekPosition Seek position in file
+ * @param $whence "Seek mode" (see http://de.php.net/fseek)
+ * @return $status Status of this operation
+ */
+ public function seek ($seekPosition, $whence = SEEK_SET) {
+ // Validate the pointer
+ $this->validateFilePointer();
+
+ // Move the file pointer
+ return fseek($this->getPointer(), $seekPosition, $whence);
+ }
+
+ /**
+ * Reads a line, maximum 4096 Bytes from current file pointer
+ *
+ * @return $data Read data from file
+ */
+ public function readLine () {
+ // Read whole line
+ return $this->read();
+ }
+
+ /**
+ * Reads given amount of bytes from file.
+ *
+ * @param $bytes Amount of bytes to read
+ * @return $data Data read from file
+ */
+ public function read ($bytes = NULL) {
+ // Validate the pointer
+ $this->validateFilePointer();
+
+ // Is $bytes set?
+ if (is_int($bytes)) {
+ // Try to read given characters
+ $data = fread($this->getPointer(), $bytes);
+ } else {
+ // Try to read whole line
+ $data = fread($this->getPointer());
+ }
+
+ // Then return it
+ return $data;
+ }
+
+ /**
+ * Analyzes entries in index file. This will count all found (and valid)
+ * entries, mark invalid as damaged and count gaps ("fragmentation"). If
+ * only gaps are found, the file is considered as "virgin" (no entries).
+ *
+ * @return void
+ * @throws UnsupportedOperationException If this method is called
+ */
+ public function analyzeFile () {
+ throw new UnsupportedOperationException(array($this, __FUNCTION__), self::EXCEPTION_UNSPPORTED_OPERATION);
+ }
+
+ /**
+ * Advances to next "block" of bytes
+ *
+ * @return void
+ * @throws UnsupportedOperationException If this method is called
+ */
+ public function next () {
+ throw new UnsupportedOperationException(array($this, __FUNCTION__), self::EXCEPTION_UNSPPORTED_OPERATION);
+ }
+
+ /**
+ * Checks wether the current entry is valid (not at the end of the file).
+ * This method will return TRUE if an emptied (nulled) entry has been found.
+ *
+ * @return $isValid Whether the next entry is valid
+ * @throws UnsupportedOperationException If this method is called
+ */
+ public function valid () {
+ throw new UnsupportedOperationException(array($this, __FUNCTION__), self::EXCEPTION_UNSPPORTED_OPERATION);
+ }
+
+ /**
+ * Gets current seek position ("key").
+ *
+ * @return $key Current key in iteration
+ * @throws UnsupportedOperationException If this method is called
+ */
+ public function key () {
+ throw new UnsupportedOperationException(array($this, __FUNCTION__), self::EXCEPTION_UNSPPORTED_OPERATION);
+ }
+
+ /**
+ * "Getter" for file size
+ *
+ * @return $fileSize Size of currently loaded file
+ */
+ public function getFileSize () {
+ // Check if the pointer is still valid
+ $this->validateFilePointer();
+
+ // Get file's data
+ $fileData = fstat($this->getPointer());
+
+ // Make sure the required array key is there
+ assert(isset($fileData['size']));
+
+ // Return size
+ return $fileData['size'];