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

   1 <?php
   2 /**
   3  * A general file-based stack class
   4  *
   5  * @author              Roland Haeder <webmaster@ship-simu.org>
   6  * @version             0.0.0
   7  * @copyright   Copyright (c) 2007, 2008 Roland Haeder, 2009 - 2013 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 BaseFileStack extends BaseStacker {
  25         /**
  26          * Magic for this stack
  27          */
  28         const STACK_MAGIC = 'STACKv0.1';
  29
  30         /**
  31          * Separator magic->count
  32          */
  33         const SEPARATOR_MAGIC_COUNT = 0x00;
  34
  35         /**
  36          * Separator position->entries
  37          */
  38         const SEPARATOR_SEEK_POS_ENTRIES = 0xff;
  39
  40         /**
  41          * Separator hash->name
  42          */
  43         const SEPARATOR_HASH_NAME = 0x05;
  44
  45         /**
  46          * Length of count
  47          */
  48         const COUNT_LENGTH = 20;
  49
  50         /**
  51          * Length of position
  52          */
  53         const COUNT_POSITION = 20;
  54
  55         /**
  56          * Counter for total entries
  57          */
  58         private $totalEntries = 0;
  59
  60         /**
  61          * Current seek position
  62          */
  63         private $seekPosition = 0;
  64
  65         /**
  66          * Protected constructor
  67          *
  68          * @param       $className      Name of the class
  69          * @return      void
  70          */
  71         protected function __construct ($className) {
  72                 // Call parent constructor
  73                 parent::__construct($className);
  74         }
  75
  76         /**
  77          * Getter for total entries
  78          *
  79          * @return      $totalEntries   Total entries in this stack
  80          */
  81         private function getCounter () {
  82                 // Get it
  83                 return $this->totalEntries;
  84         }
  85
  86         /**
  87          * Increment counter
  88          *
  89          * @return      void
  90          */
  91         private function incrementCounter () {
  92                 // Get it
  93                 $this->totalEntries++;
  94         }
  95
  96         /**
  97          * Getter for seek position
  98          *
  99          * @return      $seekPosition   Current seek position (stored here in object)
 100          */
 101         private function getSeekPosition () {
 102                 // Get it
 103                 return $this->seekPosition;
 104         }
 105
 106         /**
 107          * Setter for seek position
 108          *
 109          * @param       $seekPosition   Current seek position (stored here in object)
 110          * @return      void
 111          */
 112         private function setSeekPosition ($seekPosition) {
 113                 // And set it
 114                 $this->seekPosition = $seekPosition;
 115         }
 116
 117         /**
 118          * Updates seekPosition attribute from file to avoid to much access on file.
 119          *
 120          * @return      void
 121          */
 122         private function updateSeekPosition () {
 123                 // Get key (= seek position)
 124                 $seekPosition = $this->getIteratorInstance()->key();
 125
 126                 // And set it here
 127                 $this->setSeekPosition($seekPosition);
 128         }
 129
 130         /**
 131          * Checks whether the file header is initialized
 132          *
 133          * @return      $isInitialized  Whether the file header is initialized
 134          */
 135         private function isFileHeaderInitialized () {
 136                 /* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
 137                 // Default is not initialized
 138                 $isInitialized = FALSE;
 139
 140                 // Is the file initialized?
 141                 if ($this->isFileInitialized()) {
 142                         // Some bytes has been written, so rewind to start of it.
 143                         $rewindStatus = $this->getIteratorInstance()->rewind();
 144                         /* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] rewindStatus=%s', __METHOD__, __LINE__, $rewindStatus));
 145
 146                         // Read file header
 147                         $this->readFileHeader();
 148                 } // END - if
 149
 150                 // Return result
 151                 /* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] isInitialized=%d - EXIT!', __METHOD__, __LINE__, intval($isInitialized)));
 152                 return $isInitialized;
 153         }
 154
 155         /**
 156          * Checks whether the file-based stack has been initialized
 157          *
 158          * @return      $isInitialized          Whether the file's size is zero
 159          */
 160         private function isFileInitialized () {
 161                 // Get it from iterator which holds the pointer instance. If FALSE is returned
 162                 $fileSize = $this->getIteratorInstance()->size();
 163                 /* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] fileSize=%s', __METHOD__, __LINE__, $fileSize));
 164
 165                 /*
 166                  * The returned file size should not be FALSE or NULL as this means
 167                  * that the pointer class does not work correctly.
 168                  */
 169                 assert(is_int($fileSize));
 170
 171                 // Is more than 0 returned?
 172                 $isInitialized = ($fileSize > 0);
 173
 174                 // Return result
 175                 /* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] isInitialized=%d - EXIT!', __METHOD__, __LINE__, intval($isInitialized)));
 176                 return $isInitialized;
 177         }
 178
 179         /**
 180          * Creates the file-stack's header
 181          *
 182          * @return      void
 183          */
 184         private function createFileHeader () {
 185                 // The file's header should not be initialized here
 186                 assert(!$this->isFileHeaderInitialized());
 187
 188                 // Flush file header
 189                 $this->flushFileHeader();
 190         }
 191
 192         /**
 193          * Flushes the file header
 194          *
 195          * @return      void
 196          */
 197         private function flushFileHeader () {
 198                 // Put all informations together
 199                 $header = sprintf('%s%s%s%s%s',
 200                         // Magic
 201                         self::STACK_MAGIC,
 202
 203                         // Separator magic<->count
 204                         chr(self::SEPARATOR_MAGIC_COUNT),
 205
 206                         // Total entries (will be zero) and pad it to 20 chars
 207                         str_pad($this->dec2hex($this->getCounter()), self::COUNT_LENGTH, '0', STR_PAD_LEFT),
 208
 209                         // Position (will be zero)
 210                         str_pad($this->dec2hex(0, 2), self::COUNT_POSITION, '0', STR_PAD_LEFT),
 211
 212                         // Separator position<->entries
 213                         chr(self::SEPARATOR_SEEK_POS_ENTRIES)
 214                 );
 215
 216                 // Write it to disk (header is always at seek position 0)
 217                 $this->getIteratorInstance()->writeAtPosition(0, $header);
 218
 219                 // Update seek position
 220                 $this->updateSeekPosition();
 221         }
 222
 223         /**
 224          * Initializes this file-based stack.
 225          *
 226          * @param       $fileName       File name of this stack
 227          * @return      void
 228          */
 229         protected function initFileStack ($fileName) {
 230                 // Get a file i/o pointer instance
 231                 $pointerInstance = ObjectFactory::createObjectByConfiguredName('file_raw_input_output_class', array($fileName));
 232
 233                 // Get iterator instance
 234                 $iteratorInstance = ObjectFactory::createObjectByConfiguredName('file_io_iterator_class', array($pointerInstance));
 235
 236                 // Is the instance implementing the right interface?
 237                 assert($iteratorInstance instanceof SeekableWritableFileIterator);
 238
 239                 // Set iterator here
 240                 $this->setIteratorInstance($iteratorInstance);
 241
 242                 // Is the file's header initialized?
 243                 if ($this->isFileHeaderInitialized()) {
 244                         // Then load it
 245                         $this->loadFileHeader();
 246                 } else {
 247                         // No, then create it (which may pre-allocate the stack)
 248                         $this->createFileHeader();
 249
 250                         // And pre-allocate a bit
 251                         $this->preAllocateFile();
 252                 }
 253         }
 254
 255         /**
 256          * Initializes given stacker
 257          *
 258          * @param       $stackerName    Name of the stack
 259          * @param       $forceReInit    Force re-initialization
 260          * @return      void
 261          * @throws      AlreadyInitializedStackerException      If the stack is already initialized
 262          */
 263         public function initStack ($stackerName, $forceReInit = FALSE) {
 264                 // Is the stack already initialized?
 265                 if (($forceReInit === FALSE) && ($this->isStackInitialized($stackerName))) {
 266                         // Then throw the exception
 267                         throw new AlreadyInitializedStackerException(array($this, $stackerName, $forceReInit), self::EXCEPTION_STACKER_ALREADY_INITIALIZED);
 268                 } // END - if
 269
 270                 // Initialize the given stack
 271                 $this->partialStub('stackerName=' . $stackerName . ',forceReInit=' . intval($forceReInit));
 272         }
 273
 274         /**
 275          * Checks whether the given stack is initialized (set in array $stackers)
 276          *
 277          * @param       $stackerName    Name of the stack
 278          * @return      $isInitialized  Whether the stack is initialized
 279          */
 280         public function isStackInitialized ($stackerName) {
 281                 // Is is there?
 282                 $this->partialStub('stackerName=' . $stackerName);
 283                 $isInitialized = TRUE;
 284
 285                 // Return result
 286                 return $isInitialized;
 287         }
 288
 289         /**
 290          * Getter for size of given stack (array count)
 291          *
 292          * @param       $stackerName    Name of the stack
 293          * @return      $count                  Size of stack (array count)
 294          * @throws      NoStackerException      If given stack is missing
 295          */
 296         public function getStackCount ($stackerName) {
 297                 // Is the stack not yet initialized?
 298                 if (!$this->isStackInitialized($stackerName)) {
 299                         // Throw an exception
 300                         throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
 301                 } // END - if
 302
 303                 // Now, count the array of entries
 304                 $this->partialStub('stackerName=' . $stackerName);
 305                 $count = 0;
 306
 307                 // Return result
 308                 return $count;
 309         }
 310
 311         /**
 312          * Adds a value to given stack
 313          *
 314          * @param       $stackerName    Name of the stack
 315          * @param       $value                  Value to add to this stacker
 316          * @return      void
 317          * @throws      FullStackerException    Thrown if the stack is full
 318          */
 319         protected function addValue ($stackerName, $value) {
 320                 // Is the stack not yet initialized or full?
 321                 if (!$this->isStackInitialized($stackerName)) {
 322                         // Then do it here
 323                         $this->initStack($stackerName);
 324                 } elseif ($this->isStackFull($stackerName)) {
 325                         // Stacker is full
 326                         throw new FullStackerException(array($this, $stackerName, $value), self::EXCEPTION_STACKER_IS_FULL);
 327                 }
 328
 329                 // Now add the value to the stack
 330                 $this->partialStub('stackerName=' . $stackerName . ',value[]=' . gettype($value));
 331         }
 332
 333         /**
 334          * Get last value from named stacker
 335          *
 336          * @param       $stackerName    Name of the stack
 337          * @return      $value                  Value of last added value
 338          * @throws      NoStackerException      If the named stacker was not found
 339          * @throws      EmptyStackerException   If the named stacker is empty
 340          */
 341         protected function getLastValue ($stackerName) {
 342                 // Is the stack not yet initialized or full?
 343                 if (!$this->isStackInitialized($stackerName)) {
 344                         // Throw an exception
 345                         throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
 346                 } elseif ($this->isStackEmpty($stackerName)) {
 347                         // Throw an exception
 348                         throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
 349                 }
 350
 351                 // Now get the last value
 352                 $this->partialStub('stackerName=' . $stackerName);
 353                 $value = NULL;
 354
 355                 // Return it
 356                 return $value;
 357         }
 358
 359         /**
 360          * Get first value from named stacker
 361          *
 362          * @param       $stackerName    Name of the stack
 363          * @return      $value                  Value of last added value
 364          * @throws      NoStackerException      If the named stacker was not found
 365          * @throws      EmptyStackerException   If the named stacker is empty
 366          */
 367         protected function getFirstValue ($stackerName) {
 368                 // Is the stack not yet initialized or full?
 369                 if (!$this->isStackInitialized($stackerName)) {
 370                         // Throw an exception
 371                         throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
 372                 } elseif ($this->isStackEmpty($stackerName)) {
 373                         // Throw an exception
 374                         throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
 375                 }
 376
 377                 // Now get the first value
 378                 $this->partialStub('stackerName=' . $stackerName);
 379                 $value = NULL;
 380
 381                 // Return it
 382                 return $value;
 383         }
 384
 385         /**
 386          * "Pops" last entry from stack
 387          *
 388          * @param       $stackerName    Name of the stack
 389          * @return      $value                  Value "poped" from array
 390          * @throws      NoStackerException      If the named stacker was not found
 391          * @throws      EmptyStackerException   If the named stacker is empty
 392          */
 393         protected function popLast ($stackerName) {
 394                 // Is the stack not yet initialized or full?
 395                 if (!$this->isStackInitialized($stackerName)) {
 396                         // Throw an exception
 397                         throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
 398                 } elseif ($this->isStackEmpty($stackerName)) {
 399                         // Throw an exception
 400                         throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
 401                 }
 402
 403                 // Now, remove the last entry, we don't care about the return value here, see elseif() block above
 404                 $this->partialStub('stackerName=' . $stackerName);
 405                 return NULL;
 406         }
 407
 408         /**
 409          * "Pops" first entry from stack
 410          *
 411          * @param       $stackerName    Name of the stack
 412          * @return      $value                  Value "shifted" from array
 413          * @throws      NoStackerException      If the named stacker was not found
 414          * @throws      EmptyStackerException   If the named stacker is empty
 415          */
 416         protected function popFirst ($stackerName) {
 417                 // Is the stack not yet initialized or full?
 418                 if (!$this->isStackInitialized($stackerName)) {
 419                         // Throw an exception
 420                         throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
 421                 } elseif ($this->isStackEmpty($stackerName)) {
 422                         // Throw an exception
 423                         throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
 424                 }
 425
 426                 // Now, remove the last entry, we don't care about the return value here, see elseif() block above
 427                 $this->partialStub('stackerName=' . $stackerName);
 428                 return NULL;
 429         }
 430 }
 431
 432 // [EOF]
 433 ?>