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                 // Default is not initialized
 137                 $isInitialized = FALSE;
 138
 139                 // Is the file initialized?
 140                 if ($this->isFileInitialized()) {
 141                         // Some bytes has been written, so rewind to start of it.
 142                         $this->getIteratorInstance()->rewind();
 143
 144                         // Read file header
 145                         $this->readFileHeader();
 146                 } // END - if
 147
 148                 // Return result
 149                 return $isInitialized;
 150         }
 151
 152         /**
 153          * Checks whether the file-based stack has been initialized
 154          *
 155          * @return      $isInitialized          Whether the file's size is zero
 156          */
 157         private function isFileInitialized () {
 158                 // Default is not initialized
 159                 $isInitialized = FALSE;
 160
 161                 // Get it from iterator which holds the pointer instance. If FALSE is returned
 162                 $fileSize = $this->getIteratorInstance()->size();
 163
 164                 /*
 165                  * The returned file size should not be FALSE or NULL as this means
 166                  * that the pointer class does not work correctly.
 167                  */
 168                 assert(is_int($fileSize));
 169
 170                 // Is more than 0 returned?
 171                 if ($fileSize > 0) {
 172                         // So is the header written?
 173                         $isInitialized = $this->getIteratorInstance()->isHeaderInitialized();
 174                 } // END - if
 175
 176                 // Return result
 177                 return $isInitialized;
 178         }
 179
 180         /**
 181          * Creates the file-stack's header
 182          *
 183          * @return      void
 184          */
 185         private function createFileHeader () {
 186                 // The file's header should not be initialized here
 187                 assert(!$this->isFileHeaderInitialized());
 188
 189                 // Flush file header
 190                 $this->flushFileHeader();
 191         }
 192
 193         /**
 194          * Flushes the file header
 195          *
 196          * @return      void
 197          */
 198         private function flushFileHeader () {
 199                 // Put all informations together
 200                 $header = sprintf('%s%s%s%s%s',
 201                         // Magic
 202                         self::STACK_MAGIC,
 203
 204                         // Separator magic<->count
 205                         chr(self::SEPARATOR_MAGIC_COUNT),
 206
 207                         // Total entries (will be zero) and pad it to 20 chars
 208                         str_pad($this->dec2hex($this->getCounter()), self::COUNT_LENGTH, '0', STR_PAD_LEFT),
 209
 210                         // Position (will be zero)
 211                         str_pad($this->dec2hex(0, 2), self::COUNT_POSITION, '0', STR_PAD_LEFT),
 212
 213                         // Separator position<->entries
 214                         chr(self::SEPARATOR_SEEK_POS_ENTRIES)
 215                 );
 216
 217                 // Write it to disk (header is always at seek position 0)
 218                 $this->getIteratorInstance()->writeAtPosition(0, $header);
 219
 220                 // Update seek position
 221                 $this->updateSeekPosition();
 222         }
 223
 224         /**
 225          * Initializes this file-based stack.
 226          *
 227          * @param       $fileName       File name of this stack
 228          * @return      void
 229          */
 230         protected function initFileStack ($fileName) {
 231                 // Get a file i/o pointer instance
 232                 $pointerInstance = ObjectFactory::createObjectByConfiguredName('file_raw_input_output_class', array($fileName));
 233
 234                 // Get iterator instance
 235                 $iteratorInstance = ObjectFactory::createObjectByConfiguredName('file_io_iterator_class', array($pointerInstance));
 236
 237                 // Is the instance implementing the right interface?
 238                 assert($iteratorInstance instanceof SeekableWritableFileIterator);
 239
 240                 // Set iterator here
 241                 $this->setIteratorInstance($iteratorInstance);
 242
 243                 // Is the file's header initialized?
 244                 if ($this->isFileHeaderInitialized()) {
 245                         // Then load it
 246                         $this->loadFileHeader();
 247                 } else {
 248                         // No, then create it (which may pre-allocate the stack)
 249                         $this->createFileHeader();
 250
 251                         // And pre-allocate a bit
 252                         $this->preAllocateFile();
 253                 }
 254         }
 255
 256         /**
 257          * Initializes given stacker
 258          *
 259          * @param       $stackerName    Name of the stack
 260          * @param       $forceReInit    Force re-initialization
 261          * @return      void
 262          * @throws      AlreadyInitializedStackerException      If the stack is already initialized
 263          */
 264         public function initStack ($stackerName, $forceReInit = FALSE) {
 265                 // Is the stack already initialized?
 266                 if (($forceReInit === FALSE) && ($this->isStackInitialized($stackerName))) {
 267                         // Then throw the exception
 268                         throw new AlreadyInitializedStackerException(array($this, $stackerName, $forceReInit), self::EXCEPTION_STACKER_ALREADY_INITIALIZED);
 269                 } // END - if
 270
 271                 // Initialize the given stack
 272                 $this->partialStub('stackerName=' . $stackerName . ',forceReInit=' . intval($forceReInit));
 273         }
 274
 275         /**
 276          * Checks whether the given stack is initialized (set in array $stackers)
 277          *
 278          * @param       $stackerName    Name of the stack
 279          * @return      $isInitialized  Whether the stack is initialized
 280          */
 281         public function isStackInitialized ($stackerName) {
 282                 // Is is there?
 283                 $this->partialStub('stackerName=' . $stackerName);
 284                 $isInitialized = TRUE;
 285
 286                 // Return result
 287                 return $isInitialized;
 288         }
 289
 290         /**
 291          * Getter for size of given stack (array count)
 292          *
 293          * @param       $stackerName    Name of the stack
 294          * @return      $count                  Size of stack (array count)
 295          * @throws      NoStackerException      If given stack is missing
 296          */
 297         public function getStackCount ($stackerName) {
 298                 // Is the stack not yet initialized?
 299                 if (!$this->isStackInitialized($stackerName)) {
 300                         // Throw an exception
 301                         throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
 302                 } // END - if
 303
 304                 // Now, count the array of entries
 305                 $this->partialStub('stackerName=' . $stackerName);
 306                 $count = 0;
 307
 308                 // Return result
 309                 return $count;
 310         }
 311
 312         /**
 313          * Adds a value to given stack
 314          *
 315          * @param       $stackerName    Name of the stack
 316          * @param       $value                  Value to add to this stacker
 317          * @return      void
 318          * @throws      FullStackerException    Thrown if the stack is full
 319          */
 320         protected function addValue ($stackerName, $value) {
 321                 // Is the stack not yet initialized or full?
 322                 if (!$this->isStackInitialized($stackerName)) {
 323                         // Then do it here
 324                         $this->initStack($stackerName);
 325                 } elseif ($this->isStackFull($stackerName)) {
 326                         // Stacker is full
 327                         throw new FullStackerException(array($this, $stackerName, $value), self::EXCEPTION_STACKER_IS_FULL);
 328                 }
 329
 330                 // Now add the value to the stack
 331                 $this->partialStub('stackerName=' . $stackerName . ',value[]=' . gettype($value));
 332         }
 333
 334         /**
 335          * Get last value from named stacker
 336          *
 337          * @param       $stackerName    Name of the stack
 338          * @return      $value                  Value of last added value
 339          * @throws      NoStackerException      If the named stacker was not found
 340          * @throws      EmptyStackerException   If the named stacker is empty
 341          */
 342         protected function getLastValue ($stackerName) {
 343                 // Is the stack not yet initialized or full?
 344                 if (!$this->isStackInitialized($stackerName)) {
 345                         // Throw an exception
 346                         throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
 347                 } elseif ($this->isStackEmpty($stackerName)) {
 348                         // Throw an exception
 349                         throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
 350                 }
 351
 352                 // Now get the last value
 353                 $this->partialStub('stackerName=' . $stackerName);
 354                 $value = NULL;
 355
 356                 // Return it
 357                 return $value;
 358         }
 359
 360         /**
 361          * Get first value from named stacker
 362          *
 363          * @param       $stackerName    Name of the stack
 364          * @return      $value                  Value of last added value
 365          * @throws      NoStackerException      If the named stacker was not found
 366          * @throws      EmptyStackerException   If the named stacker is empty
 367          */
 368         protected function getFirstValue ($stackerName) {
 369                 // Is the stack not yet initialized or full?
 370                 if (!$this->isStackInitialized($stackerName)) {
 371                         // Throw an exception
 372                         throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
 373                 } elseif ($this->isStackEmpty($stackerName)) {
 374                         // Throw an exception
 375                         throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
 376                 }
 377
 378                 // Now get the first value
 379                 $this->partialStub('stackerName=' . $stackerName);
 380                 $value = NULL;
 381
 382                 // Return it
 383                 return $value;
 384         }
 385
 386         /**
 387          * "Pops" last entry from stack
 388          *
 389          * @param       $stackerName    Name of the stack
 390          * @return      $value                  Value "poped" from array
 391          * @throws      NoStackerException      If the named stacker was not found
 392          * @throws      EmptyStackerException   If the named stacker is empty
 393          */
 394         protected function popLast ($stackerName) {
 395                 // Is the stack not yet initialized or full?
 396                 if (!$this->isStackInitialized($stackerName)) {
 397                         // Throw an exception
 398                         throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
 399                 } elseif ($this->isStackEmpty($stackerName)) {
 400                         // Throw an exception
 401                         throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
 402                 }
 403
 404                 // Now, remove the last entry, we don't care about the return value here, see elseif() block above
 405                 $this->partialStub('stackerName=' . $stackerName);
 406                 return NULL;
 407         }
 408
 409         /**
 410          * "Pops" first entry from stack
 411          *
 412          * @param       $stackerName    Name of the stack
 413          * @return      $value                  Value "shifted" from array
 414          * @throws      NoStackerException      If the named stacker was not found
 415          * @throws      EmptyStackerException   If the named stacker is empty
 416          */
 417         protected function popFirst ($stackerName) {
 418                 // Is the stack not yet initialized or full?
 419                 if (!$this->isStackInitialized($stackerName)) {
 420                         // Throw an exception
 421                         throw new NoStackerException(array($this, $stackerName), self::EXCEPTION_NO_STACKER_FOUND);
 422                 } elseif ($this->isStackEmpty($stackerName)) {
 423                         // Throw an exception
 424                         throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
 425                 }
 426
 427                 // Now, remove the last entry, we don't care about the return value here, see elseif() block above
 428                 $this->partialStub('stackerName=' . $stackerName);
 429                 return NULL;
 430         }
 431 }
 432
 433 // [EOF]
 434 ?>