framework/main/classes/stacker/file/class_BaseFileStack.php

   1 <?php
   2 // Own namespace
   3 namespace CoreFramework\Stack\File;
   4
   5 // Import framework stuff
   6 use CoreFramework\Factory\ObjectFactory;
   7 use CoreFramework\Filesystem\File\BaseBinaryFile;
   8 use CoreFramework\Iterator\Filesystem\SeekableWritableFileIterator;
   9
  10 /**
  11  * A general file-based stack class
  12  *
  13  * @author              Roland Haeder <webmaster@ship-simu.org>
  14  * @version             0.0.0
  15  * @copyright   Copyright (c) 2007, 2008 Roland Haeder, 2009 - 2017 Core Developer Team
  16  * @license             GNU GPL 3.0 or any newer version
  17  * @link                http://www.ship-simu.org
  18  *
  19  * This program is free software: you can redistribute it and/or modify
  20  * it under the terms of the GNU General Public License as published by
  21  * the Free Software Foundation, either version 3 of the License, or
  22  * (at your option) any later version.
  23  *
  24  * This program is distributed in the hope that it will be useful,
  25  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  26  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  27  * GNU General Public License for more details.
  28  *
  29  * You should have received a copy of the GNU General Public License
  30  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  31  */
  32 class BaseFileStack extends BaseStacker {
  33         /**
  34          * Magic for this stack
  35          */
  36         const STACK_MAGIC = 'STACKv0.1';
  37
  38         /**
  39          * Name of array index for gap position
  40          */
  41         const ARRAY_INDEX_GAP_POSITION = 'gap';
  42
  43         /**
  44          * Name of array index for hash
  45          */
  46         const ARRAY_INDEX_HASH = 'hash';
  47
  48         /**
  49          * Name of array index for length of raw data
  50          */
  51         const ARRAY_INDEX_DATA_LENGTH = 'length';
  52
  53         /**
  54          * Protected constructor
  55          *
  56          * @param       $className      Name of the class
  57          * @return      void
  58          */
  59         protected function __construct ($className) {
  60                 // Call parent constructor
  61                 parent::__construct($className);
  62         }
  63
  64         /**
  65          * Reads the file header
  66          *
  67          * @return      void
  68          * @todo        To hard assertions here, better rewrite them to exceptions
  69          */
  70         public function readFileHeader () {
  71                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
  72
  73                 // First rewind to beginning as the header sits at the beginning ...
  74                 $this->getIteratorInstance()->rewind();
  75
  76                 // Then read it (see constructor for calculation)
  77                 $data = $this->getIteratorInstance()->read($this->getIteratorInstance()->getHeaderSize());
  78                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] Read %d bytes (%d wanted).', __METHOD__, __LINE__, strlen($data), $this->getIteratorInstance()->getHeaderSize()));
  79
  80                 // Have all requested bytes been read?
  81                 assert(strlen($data) == $this->getIteratorInstance()->getHeaderSize());
  82                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
  83
  84                 // Last character must be the separator
  85                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] data(-1)=%s', __METHOD__, __LINE__, dechex(ord(substr($data, -1, 1)))));
  86                 assert(substr($data, -1, 1) == chr(BaseBinaryFile::SEPARATOR_HEADER_ENTRIES));
  87                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
  88
  89                 // Okay, then remove it
  90                 $data = substr($data, 0, -1);
  91
  92                 // And update seek position
  93                 $this->getIteratorInstance()->updateSeekPosition();
  94
  95                 /*
  96                  * Now split it:
  97                  *
  98                  * 0 => magic
  99                  * 1 => total entries
 100                  * 2 => current seek position
 101                  */
 102                 $header = explode(chr(BaseBinaryFile::SEPARATOR_HEADER_DATA), $data);
 103
 104                 // Set header here
 105                 $this->getIteratorInstance()->setHeader($header);
 106
 107                 // Check if the array has only 3 elements
 108                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] header(%d)=%s', __METHOD__, __LINE__, count($header), print_r($header, TRUE)));
 109                 assert(count($header) == 3);
 110                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
 111
 112                 // Check magic
 113                 assert($header[0] == self::STACK_MAGIC);
 114                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
 115
 116                 // Check length of count and seek position
 117                 assert(strlen($header[1]) == BaseBinaryFile::LENGTH_COUNT);
 118                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
 119                 assert(strlen($header[2]) == BaseBinaryFile::LENGTH_POSITION);
 120                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
 121
 122                 // Decode count and seek position
 123                 $header[1] = hex2bin($header[1]);
 124                 $header[2] = hex2bin($header[2]);
 125
 126                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
 127         }
 128
 129         /**
 130          * Flushes the file header
 131          *
 132          * @return      void
 133          */
 134         public function flushFileHeader () {
 135                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
 136
 137                 // Put all informations together
 138                 $header = sprintf('%s%s%s%s%s%s',
 139                         // Magic
 140                         self::STACK_MAGIC,
 141
 142                         // Separator magic<->count
 143                         chr(BaseBinaryFile::SEPARATOR_HEADER_DATA),
 144
 145                         // Total entries (will be zero) and pad it to 20 chars
 146                         str_pad($this->dec2hex($this->getIteratorInstance()->getCounter()), BaseBinaryFile::LENGTH_COUNT, '0', STR_PAD_LEFT),
 147
 148                         // Separator count<->seek position
 149                         chr(BaseBinaryFile::SEPARATOR_HEADER_DATA),
 150
 151                         // Position (will be zero)
 152                         str_pad($this->dec2hex($this->getIteratorInstance()->getSeekPosition(), 2), BaseBinaryFile::LENGTH_POSITION, '0', STR_PAD_LEFT),
 153
 154                         // Separator position<->entries
 155                         chr(BaseBinaryFile::SEPARATOR_HEADER_ENTRIES)
 156                 );
 157
 158                 // Write it to disk (header is always at seek position 0)
 159                 $this->getIteratorInstance()->writeData(0, $header, FALSE);
 160
 161                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
 162         }
 163
 164         /**
 165          * Initializes this file-based stack.
 166          *
 167          * @param       $fileName       File name of this stack
 168          * @param       $type           Type of this stack (e.g. url_source for URL sources)
 169          * @return      void
 170          * @todo        Currently the stack file is not cached, please implement a memory-handling class and if enough RAM is found, cache the whole stack file.
 171          */
 172         protected function initFileStack ($fileName, $type) {
 173                 // Get a stack file instance
 174                 $fileInstance = ObjectFactory::createObjectByConfiguredName('stack_file_class', array($fileName, $this));
 175
 176                 // Get iterator instance
 177                 $iteratorInstance = ObjectFactory::createObjectByConfiguredName('file_iterator_class', array($fileInstance));
 178
 179                 // Is the instance implementing the right interface?
 180                 assert($iteratorInstance instanceof SeekableWritableFileIterator);
 181
 182                 // Set iterator here
 183                 $this->setIteratorInstance($iteratorInstance);
 184
 185                 // Calculate header size
 186                 $this->getIteratorInstance()->setHeaderSize(
 187                         strlen(self::STACK_MAGIC) +
 188                         strlen(chr(BaseBinaryFile::SEPARATOR_HEADER_DATA)) +
 189                         BaseBinaryFile::LENGTH_COUNT +
 190                         strlen(chr(BaseBinaryFile::SEPARATOR_HEADER_DATA)) +
 191                         BaseBinaryFile::LENGTH_POSITION +
 192                         strlen(chr(BaseBinaryFile::SEPARATOR_HEADER_ENTRIES))
 193                 );
 194
 195                 // Init counters and gaps array
 196                 $this->getIteratorInstance()->initCountersGapsArray();
 197
 198                 // Is the file's header initialized?
 199                 if (!$this->getIteratorInstance()->isFileHeaderInitialized()) {
 200                         // No, then create it (which may pre-allocate the stack)
 201                         $this->getIteratorInstance()->createFileHeader();
 202
 203                         // And pre-allocate a bit
 204                         $this->getIteratorInstance()->preAllocateFile('file_stack');
 205                 } // END - if
 206
 207                 // Load the file header
 208                 $this->readFileHeader();
 209
 210                 // Count all entries in file
 211                 $this->getIteratorInstance()->analyzeFile();
 212
 213                 /*
 214                  * Get stack index instance. This can be used for faster
 215                  * "defragmentation" and startup.
 216                  */
 217                 $indexInstance = FileStackIndexFactory::createFileStackIndexInstance($fileName, $type);
 218
 219                 // And set it here
 220                 $this->setIndexInstance($indexInstance);
 221         }
 222
 223         /**
 224          * Adds a value to given stack
 225          *
 226          * @param       $stackerName    Name of the stack
 227          * @param       $value                  Value to add to this stacker
 228          * @return      void
 229          * @throws      FullStackerException    If the stack is full
 230          */
 231         protected function addValue ($stackerName, $value) {
 232                 // Do some tests
 233                 if ($this->isStackFull($stackerName)) {
 234                         // Stacker is full
 235                         throw new FullStackerException(array($this, $stackerName, $value), self::EXCEPTION_STACKER_IS_FULL);
 236                 } // END - if
 237
 238                 // Debug message
 239                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput('[' . __METHOD__ . ':' . __LINE__ . '] stackerName=' . $stackerName . ',value[' . gettype($value) . ']=' . print_r($value, TRUE));
 240
 241                 // No objects/resources are allowed as their serialization takes to long
 242                 assert(!is_object($value));
 243                 assert(!is_resource($value));
 244
 245                 /*
 246                  * Now add the value to the file stack which returns gap position, a
 247                  * hash and length of the raw data.
 248                  */
 249                 $data = $this->getIteratorInstance()->writeValueToFile($stackerName, $value);
 250
 251                 // Add the hash and gap position to the index
 252                 $this->getIndexInstance()->addHashToIndex($stackerName, $data);
 253         }
 254
 255         /**
 256          * Get last value from named stacker
 257          *
 258          * @param       $stackerName    Name of the stack
 259          * @return      $value                  Value of last added value
 260          * @throws      EmptyStackerException   If the stack is empty
 261          */
 262         protected function getLastValue ($stackerName) {
 263                 // Is the stack not yet initialized or full?
 264                 if ($this->isStackEmpty($stackerName)) {
 265                         // Throw an exception
 266                         throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
 267                 } // END - if
 268
 269                 // Now get the last value
 270                 /* NOISY-DEBUG: */ $this->partialStub('[' . __METHOD__ . ':' . __LINE__ . '] stackerName=' . $stackerName);
 271                 $value = NULL;
 272
 273                 // Return it
 274                 return $value;
 275         }
 276
 277         /**
 278          * Get first value from named stacker
 279          *
 280          * @param       $stackerName    Name of the stack
 281          * @return      $value                  Value of last added value
 282          * @throws      EmptyStackerException   If the stack is empty
 283          */
 284         protected function getFirstValue ($stackerName) {
 285                 // Is the stack not yet initialized or full?
 286                 if ($this->isStackEmpty($stackerName)) {
 287                         // Throw an exception
 288                         throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
 289                 } // END - if
 290
 291                 // Now get the first value
 292                 /* NOISY-DEBUG: */ $this->partialStub('[' . __METHOD__ . ':' . __LINE__ . '] stackerName=' . $stackerName);
 293                 $value = NULL;
 294
 295                 // Return it
 296                 return $value;
 297         }
 298
 299         /**
 300          * "Pops" last entry from stack
 301          *
 302          * @param       $stackerName    Name of the stack
 303          * @return      $value                  Value "poped" from array
 304          * @throws      EmptyStackerException   If the stack is empty
 305          */
 306         protected function popLast ($stackerName) {
 307                 // Is the stack not yet initialized or full?
 308                 if ($this->isStackEmpty($stackerName)) {
 309                         // Throw an exception
 310                         throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
 311                 } // END - if
 312
 313                 // Now, remove the last entry, we don't care about the return value here, see elseif() block above
 314                 /* NOISY-DEBUG: */ $this->partialStub('[' . __METHOD__ . ':' . __LINE__ . '] stackerName=' . $stackerName);
 315                 return NULL;
 316         }
 317
 318         /**
 319          * "Pops" first entry from stack
 320          *
 321          * @param       $stackerName    Name of the stack
 322          * @return      $value                  Value "shifted" from array
 323          * @throws      EmptyStackerException   If the named stacker is empty
 324          */
 325         protected function popFirst ($stackerName) {
 326                 // Is the stack not yet initialized or full?
 327                 if ($this->isStackEmpty($stackerName)) {
 328                         // Throw an exception
 329                         throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
 330                 } // END - if
 331
 332                 // Now, remove the last entry, we don't care about the return value here, see elseif() block above
 333                 /* NOISY-DEBUG: */ $this->partialStub('[' . __METHOD__ . ':' . __LINE__ . '] stackerName=' . $stackerName);
 334                 return NULL;
 335         }
 336
 337         /**
 338          * Checks whether the given stack is full
 339          *
 340          * @param       $stackerName    Name of the stack
 341          * @return      $isFull                 Whether the stack is full
 342          */
 343         protected function isStackFull ($stackerName) {
 344                 // File-based stacks will only run full if the disk space is low.
 345                 // @TODO Please implement this, returning FALSE
 346                 $isFull = FALSE;
 347
 348                 // Return result
 349                 return $isFull;
 350         }
 351
 352         /**
 353          * Checks whether the given stack is empty
 354          *
 355          * @param       $stackerName            Name of the stack
 356          * @return      $isEmpty                        Whether the stack is empty
 357          * @throws      NoStackerException      If given stack is missing
 358          */
 359         public function isStackEmpty ($stackerName) {
 360                 // So, is the stack empty?
 361                 $isEmpty = (($this->getStackCount($stackerName)) == 0);
 362
 363                 // Return result
 364                 return $isEmpty;
 365         }
 366
 367         /**
 368          * Initializes given stacker
 369          *
 370          * @param       $stackerName    Name of the stack
 371          * @param       $forceReInit    Force re-initialization
 372          * @return      void
 373          * @throws      UnsupportedOperationException   This method is not (and maybe never will be) supported
 374          */
 375         public function initStack ($stackerName, $forceReInit = FALSE) {
 376                 throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
 377         }
 378
 379         /**
 380          * Initializes all stacks
 381          *
 382          * @return      void
 383          * @throws      UnsupportedOperationException   This method is not (and maybe never will be) supported
 384          */
 385         public function initStacks (array $stacks, $forceReInit = FALSE) {
 386                 throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
 387         }
 388
 389         /**
 390          * Checks whether the given stack is initialized (set in array $stackers)
 391          *
 392          * @param       $stackerName    Name of the stack
 393          * @return      $isInitialized  Whether the stack is initialized
 394          * @throws      UnsupportedOperationException   This method is not (and maybe never will be) supported
 395          */
 396         public function isStackInitialized ($stackerName) {
 397                 throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
 398         }
 399
 400         /**
 401          * Determines whether the EOF has been reached
 402          *
 403          * @return      $isEndOfFileReached             Whether the EOF has been reached
 404          * @throws      UnsupportedOperationException   This method is not (and maybe never will be) supported
 405          */
 406         public function isEndOfFileReached () {
 407                 throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
 408         }
 409
 410         /**
 411          * Getter for file name
 412          *
 413          * @return      $fileName       The current file name
 414          * @throws      UnsupportedOperationException   This method is not (and maybe never will be) supported
 415          */
 416         public function getFileName () {
 417                 throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
 418         }
 419
 420         /**
 421          * Getter for size of given stack (array count)
 422          *
 423          * @param       $stackerName    Name of the stack
 424          * @return      $count                  Size of stack (array count)
 425          */
 426         public function getStackCount ($stackerName) {
 427                 // Now, simply return the found count value, this must be up-to-date then!
 428                 return $this->getIteratorInstance()->getCounter();
 429         }
 430
 431         /**
 432          * Calculates minimum length for one entry/block
 433          *
 434          * @return      $length         Minimum length for one entry/block
 435          */
 436         public function calculateMinimumBlockLength () {
 437                 // Calulcate it
 438                 $length =
 439                         // Length of entry group
 440                         BaseBinaryFile::LENGTH_GROUP + strlen(chr(BaseBinaryFile::SEPARATOR_GROUP_HASH)) +
 441                         // Hash + value
 442                         self::getHashLength() + strlen(chr(BaseBinaryFile::SEPARATOR_HASH_VALUE)) + 1 +
 443                         // Final separator
 444                         strlen(chr(BaseBinaryFile::SEPARATOR_ENTRIES));
 445
 446                 // Return it
 447                 return $length;
 448         }
 449
 450         /**
 451          * Initializes counter for valid entries, arrays for damaged entries and
 452          * an array for gap seek positions. If you call this method on your own,
 453          * please re-analyze the file structure. So you are better to call
 454          * analyzeFile() instead of this method.
 455          *
 456          * @return      void
 457          * @throws      UnsupportedOperationException   This method is not (and maybe never will be) supported
 458          */
 459         public function initCountersGapsArray () {
 460                 throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
 461         }
 462
 463         /**
 464          * Getter for header size
 465          *
 466          * @return      $totalEntries   Size of file header
 467          * @throws      UnsupportedOperationException   This method is not (and maybe never will be) supported
 468          */
 469         public final function getHeaderSize () {
 470                 throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
 471         }
 472
 473         /**
 474          * Setter for header size
 475          *
 476          * @param       $headerSize             Size of file header
 477          * @return      void
 478          * @throws      UnsupportedOperationException   This method is not (and maybe never will be) supported
 479          */
 480         public final function setHeaderSize ($headerSize) {
 481                 throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
 482         }
 483
 484         /**
 485          * Getter for header array
 486          *
 487          * @return      $totalEntries   Size of file header
 488          * @throws      UnsupportedOperationException   This method is not (and maybe never will be) supported
 489          */
 490         public final function getHeader () {
 491                 throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
 492         }
 493
 494         /**
 495          * Setter for header
 496          *
 497          * @param       $header         Array for a file header
 498          * @return      void
 499          * @throws      UnsupportedOperationException   This method is not (and maybe never will be) supported
 500          */
 501         public final function setHeader (array $header) {
 502                 throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
 503         }
 504
 505         /**
 506          * Updates seekPosition attribute from file to avoid to much access on file.
 507          *
 508          * @return      void
 509          * @throws      UnsupportedOperationException   This method is not (and maybe never will be) supported
 510          */
 511         public function updateSeekPosition () {
 512                 throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
 513         }
 514
 515         /**
 516          * Getter for total entries
 517          *
 518          * @return      $totalEntries   Total entries in this file
 519          * @throws      UnsupportedOperationException   This method is not (and maybe never will be) supported
 520          */
 521         public final function getCounter () {
 522                 throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
 523         }
 524
 525         /**
 526          * Writes data at given position
 527          *
 528          * @param       $seekPosition   Seek position
 529          * @param       $data                   Data to be written
 530          * @param       $flushHeader    Whether to flush the header (default: flush)
 531          * @return      void
 532          * @throws      UnsupportedOperationException   This method is not (and maybe never will be) supported
 533          */
 534         public function writeData ($seekPosition, $data, $flushHeader = TRUE) {
 535                 /* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] seekPosition=%s,data[]=%s,flushHeader=%d', __METHOD__, __LINE__, $seekPosition, gettype($data), intval($flushHeader)));
 536                 throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
 537         }
 538
 539         /**
 540          * Writes given value to the file and returns a hash and gap position for it
 541          *
 542          * @param       $groupId        Group identifier
 543          * @param       $value          Value to be added to the stack
 544          * @return      $data           Hash and gap position
 545          * @throws      UnsupportedOperationException   This method is not (and maybe never will be) supported
 546          */
 547         public function writeValueToFile ($groupId, $value) {
 548                 /* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] groupId=%s,value[%s]=%s', __METHOD__, __LINE__, $groupId, gettype($value), print_r($value, TRUE)));
 549                 throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
 550         }
 551
 552         /**
 553          * Searches for next suitable gap the given length of data can fit in
 554          * including padding bytes.
 555          *
 556          * @param       $length                 Length of raw data
 557          * @return      $seekPosition   Found next gap's seek position
 558          * @throws      UnsupportedOperationException   This method is not (and maybe never will be) supported
 559          */
 560         public function searchNextGap ($length) {
 561                 /* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] length=%s', __METHOD__, __LINE__, $length));
 562                 throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
 563         }
 564
 565         /**
 566          * "Getter" for file size
 567          *
 568          * @return      $fileSize       Size of currently loaded file
 569          */
 570         public function getFileSize () {
 571                 // Call iterator's method
 572                 return $this->getIteratorInstance()->getFileSize();
 573         }
 574
 575         /**
 576          * Writes given raw data to the file and returns a gap position and length
 577          *
 578          * @param       $groupId        Group identifier
 579          * @param       $hash           Hash from encoded value
 580          * @param       $encoded        Encoded value to be written to the file
 581          * @return      $data           Gap position and length of the raw data
 582          */
 583         public function writeDataToFreeGap ($groupId, $hash, $encoded) {
 584                 // Debug message
 585                 /* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] groupId=%s,hash=%s,encoded()=%d - CALLED!', __METHOD__, __LINE__, $groupId, $hash, strlen($encoded)));
 586
 587                 // Raw data been written to the file
 588                 $rawData = sprintf('%s%s%s%s%s',
 589                         $groupId,
 590                         BaseBinaryFile::SEPARATOR_GROUP_HASH,
 591                         hex2bin($hash),
 592                         BaseBinaryFile::SEPARATOR_HASH_VALUE,
 593                         $encoded
 594                 );
 595
 596                 // Debug message
 597                 /* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] groupId=%s,hash=%s,rawData()=%d', __METHOD__, __LINE__, $groupId, $hash, strlen($rawData)));
 598
 599                 // Search for next free gap
 600                 $gapPosition = $this->getIteratorInstance()->searchNextGap(strlen($rawData));
 601
 602                 // Gap position cannot be smaller than header length + 1
 603                 assert($gapPosition > $this->getIteratorInstance()->getHeaderSize());
 604
 605                 // Debug message
 606                 /* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] groupId=%s,hash=%s,gapPosition=%s', __METHOD__, __LINE__, $groupId, $hash, $gapPosition));
 607
 608                 // Then write the data at that gap
 609                 $this->getIteratorInstance()->writeData($gapPosition, $rawData);
 610
 611                 // Debug message
 612                 /* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('[%s:%d:] groupId=%s,hash=%s,rawData()=%d - EXIT!', __METHOD__, __LINE__, $groupId, $hash, strlen($rawData)));
 613
 614                 // Return gap position, hash and length of raw data
 615                 return array(
 616                         self::ARRAY_INDEX_GAP_POSITION => $gapPosition,
 617                         self::ARRAY_INDEX_HASH         => $hash,
 618                         self::ARRAY_INDEX_DATA_LENGTH  => strlen($rawData)
 619                 );
 620         }
 621
 622 }