inc/classes/main/file_directories/class_BaseFile.php

   1 <?php
   2 /**
   3  * A general file class
   4  *
   5  * @author              Roland Haeder <webmaster@ship-simu.org>
   6  * @version             0.0.0
   7  * @copyright   Copyright (c) 2007, 2008 Roland Haeder, 2009 - 2012 Core Developer Team
   8  * @license             GNU GPL 3.0 or any newer version
   9  * @link                http://www.ship-simu.org
  10  *
  11  * This program is free software: you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation, either version 3 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  23  */
  24 class BaseFile extends BaseFrameworkSystem {
  25         /**
  26          * Separator for header data
  27          */
  28         const SEPARATOR_HEADER_DATA = 0x01;
  29
  30         /**
  31          * Separator header->entries
  32          */
  33         const SEPARATOR_HEADER_ENTRIES = 0x02;
  34
  35         /**
  36          * Separator hash->name
  37          */
  38         const SEPARATOR_HASH_NAME = 0x03;
  39
  40         /**
  41          * Separator entry->entry
  42          */
  43         const SEPARATOR_ENTRIES = 0x04;
  44
  45         /**
  46          * Separator type->position
  47          */
  48         const SEPARATOR_TYPE_POSITION = 0x05;
  49
  50         /**
  51          * Length of count
  52          */
  53         const LENGTH_COUNT = 20;
  54
  55         /**
  56          * Length of position
  57          */
  58         const LENGTH_POSITION = 20;
  59
  60         /**
  61          * Length of name
  62          */
  63         const LENGTH_NAME = 10;
  64
  65         /**
  66          * Maximum length of entry type
  67          */
  68         const LENGTH_TYPE = 20;
  69
  70         //***** Array elements for 'gaps' array *****
  71
  72         /**
  73          * Start of gap
  74          */
  75         const GAPS_INDEX_START = 'start';
  76
  77         /**
  78          * End of gap
  79          */
  80         const GAPS_INDEX_END = 'end';
  81
  82         /**
  83          * Length of output from hash()
  84          */
  85         private static $hashLength = NULL;
  86
  87         /**
  88          * Counter for total entries
  89          */
  90         private $totalEntries = 0;
  91
  92         /**
  93          * Current seek position
  94          */
  95         private $seekPosition = 0;
  96
  97         /**
  98          * Size of header
  99          */
 100         private $headerSize = 0;
 101
 102         /**
 103          * File header
 104          */
 105         private $header = array();
 106
 107         /**
 108          * Seek positions for gaps ("fragmentation")
 109          */
 110         private $gaps = array();
 111
 112         /**
 113          * Seek positions for damaged entries (e.g. mismatching hash sum, ...)
 114          */
 115         private $damagedEntries = array();
 116
 117         /**
 118          * The current file we are working in
 119          */
 120         private $fileName = '';
 121
 122         /**
 123          * Back-buffer
 124          */
 125         private $backBuffer = '';
 126
 127         /**
 128          * Currently loaded block (will be returned by current())
 129          */
 130         private $currentBlock = '';
 131
 132         /**
 133          * Protected constructor
 134          *
 135          * @param       $className      Name of the class
 136 y        * @return      void
 137          */
 138         protected function __construct ($className) {
 139                 // Call parent constructor
 140                 parent::__construct($className);
 141
 142                 // Init counters and gaps array
 143                 $this->initCountersGapsArray();
 144         }
 145
 146         /**
 147          * Destructor for cleaning purposes, etc
 148          *
 149          * @return      void
 150          */
 151         public final function __destruct() {
 152                 // Try to close a file
 153                 $this->closeFile();
 154
 155                 // Call the parent destructor
 156                 parent::__destruct();
 157         }
 158
 159         /**
 160          * Initializes counter for valid entries, arrays for damaged entries and
 161          * an array for gap seek positions. If you call this method on your own,
 162          * please re-analyze the file structure. So you are better to call
 163          * analyzeFile() instead of this method.
 164          *
 165          * @return      void
 166          */
 167         protected function initCountersGapsArray () {
 168                 // Init counter and seek position
 169                 $this->setCounter(0);
 170                 $this->setSeekPosition(0);
 171
 172                 // Init arrays
 173                 $this->gaps = array();
 174                 $this->damagedEntries = array();
 175         }
 176
 177         /**
 178          * Getter for total entries
 179          *
 180          * @return      $totalEntries   Total entries in this file
 181          */
 182         protected final function getCounter () {
 183                 // Get it
 184                 return $this->totalEntries;
 185         }
 186
 187         /**
 188          * Setter for total entries
 189          *
 190          * @param       $totalEntries   Total entries in this file
 191          * @return      void
 192          */
 193         protected final function setCounter ($counter) {
 194                 // Set it
 195                 $this->totalEntries = $counter;
 196         }
 197
 198         /**
 199          * Increment counter
 200          *
 201          * @return      void
 202          */
 203         protected final function incrementCounter () {
 204                 // Get it
 205                 $this->totalEntries++;
 206         }
 207
 208         /**
 209          * Getter for header size
 210          *
 211          * @return      $totalEntries   Size of file header
 212          */
 213         public final function getHeaderSize () {
 214                 // Get it
 215                 return $this->headerSize;
 216         }
 217
 218         /**
 219          * Setter for header size
 220          *
 221          * @param       $headerSize             Size of file header
 222          * @return      void
 223          */
 224         protected final function setHeaderSize ($headerSize) {
 225                 // Set it
 226                 $this->headerSize = $headerSize;
 227         }
 228
 229         /**
 230          * Getter for header array
 231          *
 232          * @return      $totalEntries   Size of file header
 233          */
 234         protected final function getHeade () {
 235                 // Get it
 236                 return $this->header;
 237         }
 238
 239         /**
 240          * Setter for header
 241          *
 242          * @param       $header         Array for a file header
 243          * @return      void
 244          */
 245         protected final function setHeader (array $header) {
 246                 // Set it
 247                 $this->header = $header;
 248         }
 249
 250         /**
 251          * Getter for seek position
 252          *
 253          * @return      $seekPosition   Current seek position (stored here in object)
 254          */
 255         protected final function getSeekPosition () {
 256                 // Get it
 257                 return $this->seekPosition;
 258         }
 259
 260         /**
 261          * Setter for seek position
 262          *
 263          * @param       $seekPosition   Current seek position (stored here in object)
 264          * @return      void
 265          */
 266         protected final function setSeekPosition ($seekPosition) {
 267                 // And set it
 268                 $this->seekPosition = $seekPosition;
 269         }
 270
 271         /**
 272          * Updates seekPosition attribute from file to avoid to much access on file.
 273          *
 274          * @return      void
 275          */
 276         protected function updateSeekPosition () {
 277                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
 278
 279                 // Get key (= seek position)
 280                 $seekPosition = $this->getIteratorInstance()->key();
 281                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Setting seekPosition=%s', __METHOD__, __LINE__, $seekPosition));
 282
 283                 // And set it here
 284                 $this->setSeekPosition($seekPosition);
 285
 286                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
 287         }
 288
 289         /**
 290          * Seeks to beginning of file, updates seek position in this object and
 291          * flushes the header.
 292          *
 293          * @return      void
 294          */
 295         protected function rewindUpdateSeekPosition () {
 296                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
 297
 298                 // flushFileHeader must be callable
 299                 assert(is_callable(array($this, 'flushFileHeader')));
 300
 301                 // Seek to beginning of file
 302                 $this->getIteratorInstance()->rewind();
 303
 304                 // And update seek position ...
 305                 $this->updateSeekPosition();
 306
 307                 // ... to write it back into the file
 308                 $this->flushFileHeader();
 309
 310                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!!', __METHOD__, __LINE__));
 311         }
 312
 313         /**
 314          * Seeks to old position
 315          *
 316          * @return      void
 317          */
 318         protected function seekToOldPosition () {
 319                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
 320
 321                 // Seek to currently ("old") saved position
 322                 $this->getIteratorInstance()->seek($this->getSeekPosition());
 323
 324                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!!', __METHOD__, __LINE__));
 325         }
 326
 327         /**
 328          * Checks whether the block separator has been found
 329          *
 330          * @param       $str            String to look in
 331          * @return      $isFound        Whether the block separator has been found
 332          */
 333         public static function isBlockSeparatorFound ($str) {
 334                 // Determine it
 335                 $isFound = (strpos($str, chr(self::SEPARATOR_ENTRIES)) !== FALSE);
 336
 337                 // Return result
 338                 return $isFound;
 339         }
 340
 341         /**
 342          * Getter for the file pointer
 343          *
 344          * @return      $filePointer    The file pointer which shall be a valid file resource
 345          * @throws      UnsupportedOperationException   If this method is called
 346          */
 347         public final function getPointer () {
 348                 throw new UnsupportedOperationException(array($this, __FUNCTION__), self::EXCEPTION_UNSPPORTED_OPERATION);
 349         }
 350
 351         /**
 352          * Setter for file name
 353          *
 354          * @param       $fileName       The new file name
 355          * @return      void
 356          */
 357         protected final function setFileName ($fileName) {
 358                 $fileName = (string) $fileName;
 359                 $this->fileName = $fileName;
 360         }
 361
 362         /**
 363          * Getter for file name
 364          *
 365          * @return      $fileName       The current file name
 366          */
 367         public final function getFileName () {
 368                 return $this->fileName;
 369         }
 370
 371         /**
 372          * Initializes the back-buffer by setting it to an empty string.
 373          *
 374          * @return      void
 375          */
 376         private function initBackBuffer () {
 377                 // Simply call the setter
 378                 $this->setBackBuffer('');
 379         }
 380
 381         /**
 382          * Setter for backBuffer field
 383          *
 384          * @param       $backBuffer             Characters to "store" in back-buffer
 385          * @return      void
 386          */
 387         private function setBackBuffer ($backBuffer) {
 388                 // Cast to string (so no arrays or objects)
 389                 $backBuffer = (string) $backBuffer;
 390
 391                 // ... and set it
 392                 $this->backBuffer = $backBuffer;
 393         }
 394
 395         /**
 396          * Getter for backBuffer field
 397          *
 398          * @return      $backBuffer             Characters "stored" in back-buffer
 399          */
 400         private function getBackBuffer () {
 401                 return $this->backBuffer;
 402         }
 403
 404         /**
 405          * Setter for currentBlock field
 406          *
 407          * @param       $currentBlock           Characters to set a currently loaded block
 408          * @return      void
 409          */
 410         private function setCurrentBlock ($currentBlock) {
 411                 // Cast to string (so no arrays or objects)
 412                 $currentBlock = (string) $currentBlock;
 413
 414                 // ... and set it
 415                 $this->currentBlock = $currentBlock;
 416         }
 417
 418         /**
 419          * Gets currently read data
 420          *
 421          * @return      $current        Currently read data
 422          */
 423         public function getCurrentBlock () {
 424                 // Return it
 425                 return $this->currentBlock;
 426         }
 427
 428         /**
 429          * Initializes this file class
 430          *
 431          * @param       $fileName       Name of this abstract file
 432          * @return      void
 433          */
 434         protected function initFile ($fileName) {
 435                 // Get a file i/o pointer instance
 436                 $pointerInstance = ObjectFactory::createObjectByConfiguredName('file_raw_input_output_class', array($fileName));
 437
 438                 // ... and set it here
 439                 $this->setPointerInstance($pointerInstance);
 440         }
 441
 442         /**
 443          * Writes data at given position
 444          *
 445          * @param       $seekPosition   Seek position
 446          * @param       $data                   Data to be written
 447          * @param       $flushHeader    Whether to flush the header (default: flush)
 448          * @return      void
 449          */
 450         protected function writeData ($seekPosition, $data, $flushHeader = TRUE) {
 451                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] seekPosition=%s,data()=%s - CALLED!', __METHOD__, __LINE__, $seekPosition, strlen($data)));
 452
 453                 // Write data at given position
 454                 $this->getPointerInstance()->writeAtPosition($seekPosition, $data);
 455
 456                 // Update seek position
 457                 $this->updateSeekPosition();
 458
 459                 // Flush the header?
 460                 if ($flushHeader === TRUE) {
 461                         // Flush header
 462                         $this->flushFileHeader();
 463
 464                         // Seek to old position
 465                         $this->seekToOldPosition();
 466                 } // END - if
 467
 468                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
 469         }
 470
 471         /**
 472          * Marks the currently loaded block as empty (with length of the block)
 473          *
 474          * @param       $length         Length of the block
 475          * @return      void
 476          */
 477         protected function markCurrentBlockAsEmpty ($length) {
 478                 // Get current seek position
 479                 $currentPosition = $this->key();
 480
 481                 // Now add it as gap entry
 482                 array_push($this->gaps, array(
 483                         self::GAPS_INDEX_START  => ($currentPosition - $length),
 484                         self::GAPS_INDEX_END    => $currentPosition,
 485                 ));
 486         }
 487
 488         /**
 489          * Checks whether the file header is initialized
 490          *
 491          * @return      $isInitialized  Whether the file header is initialized
 492          */
 493         public function isFileHeaderInitialized () {
 494                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
 495
 496                 // Default is not initialized
 497                 $isInitialized = FALSE;
 498
 499                 // Is the file initialized?
 500                 if ($this->isFileInitialized()) {
 501                         // Some bytes has been written, so rewind to start of it.
 502                         $rewindStatus = $this->rewind();
 503                         //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] rewindStatus=%s', __METHOD__, __LINE__, $rewindStatus));
 504
 505                         // Is the rewind() call successfull?
 506                         if ($rewindStatus != 1) {
 507                                 // Something bad happened
 508                                 self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Could not rewind().', __METHOD__, __LINE__));
 509                         } // END - if
 510
 511                         // Read file header
 512                         $this->readFileHeader();
 513
 514                         // The above method does already check the header
 515                         $isInitialized = TRUE;
 516                 } // END - if
 517
 518                 // Return result
 519                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] isInitialized=%d - EXIT!', __METHOD__, __LINE__, intval($isInitialized)));
 520                 return $isInitialized;
 521         }
 522
 523         /**
 524          * Checks whether the assigned file has been initialized
 525          *
 526          * @return      $isInitialized          Whether the file's size is zero
 527          */
 528         public function isFileInitialized () {
 529                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
 530
 531                 // Get it from iterator which holds the pointer instance. If FALSE is returned
 532                 $fileSize = $this->size();
 533                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] fileSize=%s', __METHOD__, __LINE__, $fileSize));
 534
 535                 /*
 536                  * The returned file size should not be FALSE or NULL as this means
 537                  * that the pointer class does not work correctly.
 538                  */
 539                 assert(is_int($fileSize));
 540
 541                 // Is more than 0 returned?
 542                 $isInitialized = ($fileSize > 0);
 543
 544                 // Return result
 545                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] isInitialized=%d - EXIT!', __METHOD__, __LINE__, intval($isInitialized)));
 546                 return $isInitialized;
 547         }
 548
 549         /**
 550          * Creates the assigned file
 551          *
 552          * @return      void
 553          */
 554         public function createFileHeader () {
 555                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
 556
 557                 // The file's header should not be initialized here
 558                 assert(!$this->isFileHeaderInitialized());
 559
 560                 // Simple flush file header which will create it.
 561                 $this->flushFileHeader();
 562
 563                 // Rewind seek position (to beginning of file) and update/flush file header
 564                 $this->rewindUpdateSeekPosition();
 565
 566                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!!', __METHOD__, __LINE__));
 567         }
 568
 569         /**
 570          * Pre-allocates file (if enabled) with some space for later faster write access.
 571          *
 572          * @param       $type   Type of the file
 573          * @return      void
 574          */
 575         public function preAllocateFile ($type) {
 576                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
 577
 578                 // Is it enabled?
 579                 if ($this->getConfigInstance()->getConfigEntry($type . '_pre_allocate_enabled') != 'Y') {
 580                         // Not enabled
 581                         self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Not pre-allocating file.', __METHOD__, __LINE__));
 582
 583                         // Don't continue here.
 584                         return;
 585                 } // END - if
 586
 587                 // Message to user
 588                 self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Pre-allocating file ...', __METHOD__, __LINE__));
 589
 590                 // Calculate minimum length for one entry
 591                 $minLengthEntry = $this->getBlockInstance()->calculateMinimumBlockLength();
 592                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] minLengthEntry=%s', __METHOD__, __LINE__, $minLengthEntry));
 593
 594                 // Calulcate seek position
 595                 $seekPosition = $minLengthEntry * $this->getConfigInstance()->getConfigEntry($type . '_pre_allocate_count');
 596                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] seekPosition=%s', __METHOD__, __LINE__, $seekPosition));
 597
 598                 // Now simply write a NUL there. This will pre-allocate the file.
 599                 $this->writeData($seekPosition, chr(0));
 600
 601                 // Rewind seek position (to beginning of file) and update/flush file header
 602                 $this->rewindUpdateSeekPosition();
 603
 604                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
 605         }
 606
 607         /**
 608          * Close a file source and set it's instance to null and the file name
 609          * to empty
 610          *
 611          * @return      void
 612          * @todo        ~10% done?
 613          */
 614         public function closeFile () {
 615                 $this->partialStub('Unfinished method.');
 616
 617                 // Remove file name
 618                 $this->setFileName('');
 619         }
 620
 621         /**
 622          * Determines seek position
 623          *
 624          * @return      $seekPosition   Current seek position
 625          */
 626         public function determineSeekPosition () {
 627                 // Call pointer instance
 628                 return $this->getPointerInstance()->determineSeekPosition();
 629         }
 630
 631         /**
 632          * Seek to given offset (default) or other possibilities as fseek() gives.
 633          *
 634          * @param       $offset         Offset to seek to (or used as "base" for other seeks)
 635          * @param       $whence         Added to offset (default: only use offset to seek to)
 636          * @return      $status         Status of file seek: 0 = success, -1 = failed
 637          */
 638         public function seek ($offset, $whence = SEEK_SET) {
 639                 // Call pointer instance
 640                 return $this->getPointerInstance()->seek($offset, $whence);
 641         }
 642
 643         /**
 644          * Size of this file
 645          *
 646          * @return      $size   Size (in bytes) of file
 647          * @todo        Handle seekStatus
 648          */
 649         public function size () {
 650                 // Call pointer instance
 651                 return $this->getPointerInstance()->size();
 652         }
 653
 654         /**
 655          * Read data a file pointer
 656          *
 657          * @return      mixed   The result of fread()
 658          * @throws      NullPointerException    If the file pointer instance
 659          *                                                                      is not set by setPointer()
 660          * @throws      InvalidResourceException        If there is being set
 661          */
 662         public function readFromFile () {
 663                 // Call pointer instance
 664                 return $this->getPointerInstance()->readFromFile();
 665         }
 666
 667         /**
 668          * Reads given amount of bytes from file.
 669          *
 670          * @param       $bytes  Amount of bytes to read
 671          * @return      $data   Data read from file
 672          */
 673         public function read ($bytes) {
 674                 // Call pointer instance
 675                 return $this->getPointerInstance()->read($bytes);
 676         }
 677
 678         /**
 679          * Write data to a file pointer
 680          *
 681          * @param       $dataStream             The data stream we shall write to the file
 682          * @return      mixed                   Number of writes bytes or FALSE on error
 683          * @throws      NullPointerException    If the file pointer instance
 684          *                                                                      is not set by setPointer()
 685          * @throws      InvalidResourceException        If there is being set
 686          *                                                                                      an invalid file resource
 687          */
 688         public function writeToFile ($dataStream) {
 689                 // Call pointer instance
 690                 return $this->getPointerInstance()->writeToFile($dataStream);
 691         }
 692
 693         /**
 694          * Rewinds to the beginning of the file
 695          *
 696          * @return      $status         Status of this operation
 697          */
 698         public function rewind () {
 699                 // Call pointer instance
 700                 return $this->getPointerInstance()->rewind();
 701         }
 702
 703         /**
 704          * Determines whether the EOF has been reached
 705          *
 706          * @return      $isEndOfFileReached             Whether the EOF has been reached
 707          */
 708         public final function isEndOfFileReached () {
 709                 // Call pointer instance
 710                 return $this->getPointerInstance()->isEndOfFileReached();
 711         }
 712
 713         /**
 714          * Analyzes entries in index file. This will count all found (and valid)
 715          * entries, mark invalid as damaged and count gaps ("fragmentation"). If
 716          * only gaps are found, the file is considered as "virgin" (no entries).
 717          *
 718          * @return      void
 719          */
 720         public function analyzeFile () {
 721                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
 722
 723                 // Make sure the file is initialized
 724                 assert($this->isFileInitialized());
 725
 726                 // Init counters and gaps array
 727                 $this->initCountersGapsArray();
 728
 729                 // Output message (as this may take some time)
 730                 self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Analyzing file structure ... (this may take some time)', __METHOD__, __LINE__));
 731
 732                 // First rewind to the begining
 733                 $this->rewind();
 734
 735                 // Then try to load all entries
 736                 while ($this->valid()) {
 737                         // Go to next entry
 738                         $this->next();
 739
 740                         // Get current entry
 741                         $current = $this->getCurrentBlock();
 742
 743                         // Debug message
 744                         /* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] current()=%s', __METHOD__, __LINE__, strlen($current)));
 745                 } // END - while
 746
 747                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
 748         }
 749
 750         /**
 751          * Advances to next "block" of bytes
 752          *
 753          * @return      void
 754          */
 755         public function next () {
 756                 // Is there nothing to read?
 757                 if (!$this->valid()) {
 758                         // Nothing to read
 759                         return;
 760                 } // END - if
 761
 762                 // Make sure the block instance is set
 763                 assert($this->getBlockInstance() instanceof CalculatableBlock);
 764
 765                 // First calculate minimum block length
 766                 $length = $this->getBlockInstance()->calculateMinimumBlockLength();
 767
 768                 // Short be more than zero!
 769                 assert($length > 0);
 770
 771                 // Read possibly back-buffered bytes from previous call of next().
 772                 $data = $this->getBackBuffer();
 773
 774                 /*
 775                  * Read until a entry/block separator has been found. The next read
 776                  * "block" may not fit, so this loop will continue until the EOB or EOF
 777                  * has been reached whatever comes first.
 778                  */
 779                 while ((!$this->isEndOfFileReached()) && (!self::isBlockSeparatorFound($data))) {
 780                         // Then read the next possible block
 781                         $block = $this->read($length);
 782
 783                         // Is it all empty?
 784                         if (strlen(trim($block)) == 0) {
 785                                 // Mark this block as empty
 786                                 $this->markCurrentBlockAsEmpty($length);
 787
 788                                 // Skip to next block
 789                                 continue;
 790                         } // END - if
 791
 792                         // At this block then
 793                         $data .= $block;
 794
 795                         // A debug message
 796                         //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d] data()=%s', __FUNCTION__, __LINE__, strlen($data)));
 797                 } // END - if
 798
 799                 // EOF reached?
 800                 if ($this->isEndOfFileReached()) {
 801                         // Set whole data as current read block
 802                         //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('Calling setCurrentBlock(' . strlen($data) . ') ...');
 803                         $this->setCurrentBlock($data);
 804
 805                         // Then abort here silently
 806                         //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('EOF reached.');
 807                         return;
 808                 } // END - if
 809
 810                 /*
 811                  * Init back-buffer which is the data that has been found beyond the
 812                  * separator.
 813                  */
 814                 $this->initBackBuffer();
 815
 816                 // Separate data
 817                 $dataArray = explode(chr(self::SEPARATOR_ENTRIES), $data);
 818
 819                 // This array must contain two elements
 820                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('dataArray=' . print_r($dataArray, TRUE));
 821                 assert(count($dataArray) == 2);
 822
 823                 // Left part is the actual block, right one the back-buffer data
 824                 $this->setCurrentBlock($dataArray[0]);
 825                 $this->setBackBuffer($dataArray[1]);
 826         }
 827
 828         /**
 829          * Checks wether the current entry is valid (not at the end of the file).
 830          * This method will return TRUE if an emptied (nulled) entry has been found.
 831          *
 832          * @return      $isValid        Whether the next entry is valid
 833          */
 834         public function valid () {
 835                 // Make sure the block instance is set
 836                 assert($this->getBlockInstance() instanceof Block);
 837
 838                 // First calculate minimum block length
 839                 $length = $this->getBlockInstance()->calculateMinimumBlockLength();
 840
 841                 // Short be more than zero!
 842                 assert($length > 0);
 843
 844                 // Get current seek position
 845                 $seekPosition = $this->key();
 846
 847                 // Then try to read it
 848                 $data = $this->read($length);
 849
 850                 // If some bytes could be read, all is fine
 851                 $isValid = ((is_string($data)) && (strlen($data) > 0));
 852
 853                 // Get header size
 854                 $headerSize = $this->getBlockInstance()->getHeaderSize();
 855
 856                 // Is the seek position at or beyond the header?
 857                 if ($seekPosition >= $headerSize) {
 858                         // Seek back to old position
 859                         $this->seek($seekPosition);
 860                 } else {
 861                         // Seek directly behind the header
 862                         $this->seek($headerSize);
 863                 }
 864
 865                 // Return result
 866                 return $isValid;
 867         }
 868
 869         /**
 870          * Gets current seek position ("key").
 871          *
 872          * @return      $key    Current key in iteration
 873          */
 874         public function key () {
 875                 // Call pointer instance
 876                 return $this->getPointerInstance()->determineSeekPosition();
 877         }
 878
 879         /**
 880          * Reads the file header
 881          *
 882          * @return      void
 883          */
 884         public function readFileHeader () {
 885                 // Make sure the block instance is set
 886                 assert($this->getBlockInstance() instanceof Block);
 887
 888                 // Call block instance
 889                 $this->getBlockInstance()->readFileHeader();
 890         }
 891
 892         /**
 893          * Flushes the file header
 894          *
 895          * @return      void
 896          */
 897         public function flushFileHeader () {
 898                 // Make sure the block instance is set
 899                 assert($this->getBlockInstance() instanceof Block);
 900
 901                 // Call block instance
 902                 $this->getBlockInstance()->flushFileHeader();
 903         }
 904 }
 905
 906 // [EOF]
 907 ?>